Comet PanSTARRS, and other targets of opportunity

I had a short but very fun stargazing session tonight. I went to the top of the parking garage in downtown Claremont to look for Comet PanSTARRS. I knew that it would be horizonwards and a little right of the moon. I took the Apex 127/SV50 combo and my 15×70 binoculars. I got set up a little after 7:15 PM and started scanning the western sky, using the 15x70s and SV50 in alternation.

At 7:25 I spotted the comet in binoculars. It was down in the bright twilight glow, but it was surprisingly bright itself. Like a lot of things that you spot just as they’re coming out in the evening, once I’d found it I thought, “Dang, that’s bright, how did I miss it before now?”

Binoculars are pretty much guaranteed to be the best instrument for first picking up the comet, but it is big and bright enough to be a very rewarding telescopic target, and if you only see it in binoculars, you will definitely be missing out. Here’s a little trick for getting it in the scope: once you have it in the binoculars, scan straight down to the horizon–which ain’t far–and find a landmark. Go back up and relocate the comet, then back down again to make sure you’ve got the right landmark (I didn’t, the first time–I’d let the bins drift too much to the right on the way down). Anyway, once you’ve got the landmark, you’re golden: point the scope at the landmark and scan up to find the comet.

At 64x in the Apex 127, the nucleus seemed to be an extended object, not just a point of light. The tail swept straight up. I thought it was a little brighter and a little crisper on the north (right side in the sky, but left side in the scope). I wish I had sketched it–I’ll do that next time out.

Just a few minutes after I got the comet in my sights, a young couple pulled up and parked nearby, and invited them over to see the comet and the thin crescent moon. When the young woman saw the moon in the scope, she jerked back from the eyepiece, shook her hands, and said that the view had given her the chills. When people ask why I do sidewalk astronomy, I tell them about things like that.

Later on a family of five pulled up and I showed all of them the comet and the moon. So I had an astronomy outreach to a total of seven guests tonight. My favorite part: helping a 6-year-old kid get the 15x70s balanced on the side rail of the parking garage so he could see the moon.

If you’d like to see the comet, your best chances are in the next week or two. It will probably be bright enough to see with a telescope for weeks after that, maybe even months, but it isn’t going to get any brighter. Get over to Sky&Tel or just google “comet PanSTARRS”–the internet is falling over itself giving out instructions on how to find the comet right now.

By 7:50 all my visitors had moved on and so had the comet, lost in the hazy clouds over Los Angeles. I wasn’t done, though.

Urban decay

As I’m sure I’ve mentioned here before, I’m closing in on finishing two of the Astronomical League’s observing programs, the Urban Observing Club and the Double Star Club. If I’d gotten my rear in gear a month ago I could have finished them both easily by now, but my head was stuck in the Jurassic and I let too much time slip by. As of a couple of days ago, I only needed two more objects for each club: M77 and Algol for the Urban Club, and Alpha Piscium and 8 Lacertae for the Double Star Club. The trouble is, they’re all low in the western sky now, and in a month or  two they’ll be right behind the sun. So if I don’t get them pronto, I’ll have to wait a while before I’ll get another crack at them.

I got M77 Monday night from my driveway. I’d also seen it Saturday night on my Messier Marathon, of course, but that didn’t count; to be eligible for the Urban Club, the observations  have to made from someplace sufficiently light-polluted that the Milky Way is not naked-eye visible. Fortunately this galaxy has a crazy-bright core and I caught it with averted vision from the driveway even though it wasn’t fully dark yet. My time limit was set less by the sky and more by local geography: when I saw it, it was already in between the leafless branches of one of the trees in my back yard.

Algol is up in Perseus, still a good 25 or 30 degrees above the horizon at sunset, so it’s easy enough to see. That ain’t the problem. It’s the only variable star on the Urban Observing list, so I reckon I haven’t fulfilled the spirit of the thing until I’ve seen it go through one of its periodic brightness variations. These happen about every three days, which sounds great, except that they’re offset so most of them happen during the day, or when the constellation has already set. I need one of those minima to hit between about 7:00 and 9:00 PM, which is a pretty darned narrow window (why oh why didn’t I just see this thing a month ago?). I just missed one on March 7, when my head was still only in the Jurassic. The next one that is in my time window is on the evening of March 27, when I’m scheduled to be on an airplane between Texas and SoCal. The next good one after that isn’t until April 16. That one may just be doable–Perseus is far enough north that it sets pretty late from my latitude (from 40 degrees and points farther north, it doesn’t set at all).

Doing the splits can be painful

I have been kicking and kicking myself for not getting Alpha Piscium and 8 Lacertae in the past few months when they were dead overhead. I actually got Alpha Piscium in they eyepiece one night a week or two ago, but I couldn’t split it before it got lost in the trees. I found out why tonight: it’s a darned hard split.

After the comet and all my visitors had departed, I went straight to Alpha Piscium. It was already down into the near-horizon murk, which makes stars take on interesting shapes and colors that often have nothing to do with their normal night-sky appearances. At 64x it was just a dot. Same thing at 128x. Same thing at 257x, at least at first glance. But then the seeing steadied for a crucial moment and I was able to get the focus dialed in, and there it was: a double star. At high magnification in the Mak, each star is  surrounded by a neat little diffraction ring. At 257x, Alpha Piscium’s secondary component was sitting on the diffraction ring of the brighter primary, as if the primary  was sitting in the middle of a diamond ring. Like this, only I couldn’t see the diffraction ring around the secondary star so clearly. Anyway, it was a pretty sight and a righteous split.

That left me in the same place in the Double Star Club that I am in the Urban Club: 99 down, one to go. I thought that 8 Lacertae might just be possible, so I started star-hopping over that way. I almost got there, too, but just in time to see the lizard’s tail dip below the local horizon. I am pretty sure that if I try again in the next couple of nights, and go to 8 Lacertae before I  do anything else, I’ll be able to get it. It’s a nice wide multiple star, so it shouldn’t be a tough split, if I can just get on target before it sets.

Another crazy good scope deal

Finally, I’d be remiss if I didn’t point this out: Orion has put their 20×50 compact spotting scope on clearance for $29.99. You can get it through the Orion site or this Amazon link. I am familiar with this scope–London and I gave it a test drive at the Orion store in Watsonville last summer, and on the strength of that encounter London asked for and received one for his birthday last November. We’ve had it out to the Salton Sea a couple of times now, so we’ve gotten to use it for daytime spotting and out under the stars.

How does it do? Well, it’s a 50mm spotting scope, and like most such devices, it basically is a finderscope and has no other finder or provision for one. Also, you’re stuck at 20x. So for nighttime use, you’re going to get binocular-esque views of the moon, planets, and a handful of the brighter DSOs (think Pleiades, Orion, Andromeda) and that’s about it. Also, it’s a short, fast refractor, so there is some false color on bright objects. To be fair, though, almost all spotting scopes are short, fast refractors (‘cept for the Maks), and other than the ED models that cost hundreds to thousands, they all show chromatic aberration. Even my beloved SV50 throws up some false color, and I don’t think the Orion spotter is noticeably worse in this regard.

It’s much more rewarding to use during the daytime. I don’t know why Orion is closing them out, but it probably isn’t image quality, because the two I’ve looked through have been nice and sharp. In addition to the zippered soft-side storage case, the scope comes with a velcro-tabbed, padded fabric wrap-around, similar to the weather-resistant ‘view-through’ cases on some high-end spotters (but offering less than total coverage). This has a padded hand-strap so you can take the scope off a tripod (not included, nor would you want any tripod they could include at this price point–trust me) and use it handheld. This is surprisingly effective, and London and I have taken to carrying his scope along on our morning hikes when we’re camping.

Any downsides, aside from the aforementioned false color? The helical focuser was a little stiff for the first few uses. The usual solution with sticky focusers is to twist them all the way in and out a few times to get the lubricant evenly distributed over all the surfaces. I did that with London’s spotting scope and sure enough, the problem went away. Focusing is a breeze now.

Raw, unmodified photo of some gulls at about 50 yards, taken afocally through the Orion 20×50 compact spotting scope using my Nikon Coolpix 4500.

So, long story short, I dunno why Orion is closing these out, because I think they’re fine little scopes. I haven’t noticed any lasting problems in several days and nights of field use, and if I didn’t already have a 50mm scope of my own, I’d be all over this. It’s a decent buy at $50 and a steal at $30. If you need a small spotting scope, period, or something to keep in the car for impromptu scenery- or wildlife-watching sessions, or something for that kid you know who is interested in nature and science, this thing ought to fill the bill. I’m tempted to get another one myself, to keep in the storage compartment under the back seat of the Mazda. But if you’re interested, don’t tarry–Orion is already out of the spotting-scope-plus-tripod packages, and I don’t imagine the scopes themselves will last long at this price.

Mt Wilson 60-inch telescope model by Barry Crist

I bought a new telescope–my smallest yet.

The 60-inch telescope at Mount Wilson not only played a big role in the history of astronomy, it also played a big role in my history in astronomy (see this and this). So I was happy to get one of the last models of the grand machine made by miniature telescope maker extraordinaire, Barry Crist.

Yes, there’s a mirror down there. Two, in fact–a primary mirror and a tertiary to send the light out the side of the scope to the eyepiece.

There’s the tertiary mirror lurking amidst the faux ironwork. There’s also a secondary mirror up at the front end, but I couldn’t get a clean shot of it. The mirrors aren’t image-forming and the eyepiece is just a painted plug, but still–little mirrors! So cool. And as the photos show, the little equatorial fork turns in both right ascension and declination.

And there’s the maker’s serial number cleverly hidden away at the back of the fork.

Unfortunately, these aren’t available anymore. I got one of the last three, and apparently Mr. Crist has no plans to make any more. There are still a few models of the 100-inch Hooker telescope available, which is made to the same scale as the 60-inch. Details here, while they last.

The miniature 60-inch and 100-inch telescopes by Barry Crist. Photo from the Mount Wilson Observatory website.

Gear reports: Explore Scientific eyepieces, Orion Apex 127 Mak, Celestron Travel Scope 70

Apex 127 (left) and Travel Scope 70 (right) under dark skies on Mount Baldy. The Apex is on a SkyWatcher AZ4 mount, and the TS70 is on a Manfrotto CXPRO4 with a Universal Astronomics DwarfStar alt-az head. Photo by Terry Nakazono.

As promised in the last post, here are my thoughts on the scopes and charts I used up on Mount Baldy Saturday night. I haven’t had half of this stuff long enough for these to be considered true reviews, so I’m calling them “gear reports”.

Explore Scientific eyepieces–For  a long time my workhorse eyepieces have been 32mm and 12mm Plossls and the 6mm Expanse. The 24mm ES68 gives the same true field as the 32mm Plossl but with higher magnification and a larger apparent field–68 degrees versus 52. The 14mm and 8.8mm ES82s give me a nice pair of mid-to-high power options, without taking business away from the 6mm Expanse.

How important is all that apparent field of view? I’ve also had the opportunity recently to look through a few TeleVue Ethos 100-degree eyepieces, and here are my impressions.

• Ethos: I could not quite see all of the field of view at once. I had to actually move my head around to see the field stop. It was nice–when I first looked in the eyepiece, at what was in the middle of the field, I could not immediately see the field stop in any direction. It actually was like looking through a window into space. I can see why people shell out big bucks for this experience (think $600 and up for the TeleVue Ethos models and $400 and up for the other brands).
• ES82: I can see all of the field and the field stop at once, but it is so far out to the edge of my field of view that I am not really aware of it. Very comfortable, too, in terms of eye placement and eye relief.
• ES68 and Orion Expanse (66-degree apparent field): ditto. For me, the jump from 52 degrees to 66 or 68 degrees is much more noticeable than the jump from the sixties up to 82–or back. I never went from one of the 82s to one of the sixties and thought, “oh, hey, where did my extra field go?”, which definitely does happen when I go directly from a widefield to a Plossl. My only explanation is that, at least for me, 66-68 degrees is over a threshold where additional apparent field makes little difference, until the I-can’t-see-it-all-at-once threshold I get with the Ethos.
• Plossls (52-degree apparent field): I like Plossls. They’re good, solid workhorse eyepieces, that can handle a wide range of focal ratios and tend to be sharp and have good light throughput. They were my go-to eyepieces for years. But, like many, many stargazers before me, I am spoiled now. The fact is, after using 66-82 degree eyepieces (I’ve had a pair of 68-degree Orion Stratuses for a couple of years, and just not used them much), going back to the Plossls is like being struck with tunnel vision: I am acutely aware that a lot of my visual real estate is occupied by non-sky inside-of-eyepiece black nothingness. That said, the effect really only jumps out at me when I swap a widefield for a Plossl back to back in the same scope. Saturday night I would be observing with widefields in the Apex and then wander over to the TS70 with the 32mm Plossl and not notice the sudden decrease in field. So I’m not getting rid of my Plossls anytime soon. For one thing, they all weigh much less than their widefield counterparts, and so play better in small scopes and travel kits.

By the way, if you’re in the market for budget Plossls and Expanse clones, check out the Black Knight Super Plossls and Enhanced Super-Wides at OWL Astronomy.

Apex 127–Under dark skies, a potent deep-sky instrument. Its maximum true field of just a bit over a degree will frame almost all deep sky objects, except for the very closest open clusters (like the Pleiades and Hyades). Everything I tried for, I found–my problems with the two open clusters were not that I could not see them, but that I could tell exactly what parts of the rich Milky Way starfields were supposed to be the clusters–more on this farther down. It’s also a planet-killer and excellent double-star scope. One night this spring I was trying to split a particularly tough double with this scope. It refused to budge at 257x, so I Barlowed my 6mm expanse to give 514x, and finally saw that stripe of black sky between the two stars. That’s about 100x per inch of aperture, or twice the rule-of-thumb “maximum effective magnification” of 50x per inch. Which means it’s a damn fine scope.

Travel Scope 70–Four things about this scope, three good, and one not so good. The good stuff first.

• It costs next to nothing. As I’ve pointed out in other posts, you can’t buy a 9×50 right-angle correct-image finder for what they’re charging for this scope.
• It’s small and light. I think it would ride on the same tripod as my SV50 and the scope itself takes up hardly any more room, but 70mm gathers roughly twice as much light as 50mm (5*5=25, 7*7=49). It has the same focal length as the venerable Short Tube 80 but weighs about half as much. You could think of it as a Short Tube 70, but its focal ratio of 5.7 is a hair more forgiving. That combined with the slightly smaller aperture should knock down the chromatic aberration a bit, compared to the ST80, and indeed I’ve found the CA unnoticeable in casual use, even on the moon and  planets (that is, I’m sure it’s there if one goes hunting, but it’s never risen to the level of attracting my attention at the eyepiece).
• The optics are wonderfully clear. The low-power views are really bright and contrasty. I noticed this the first night I had the scope. I was cruising the summer Milky Way from my driveway, trying the 12.5x view with the 32mm Plossl for the first time. Now, Lyra was dead overhead, and atmospheric problems are almost always minimized at the zenith, but still, the view was bright, and I found the Ring Nebula, M57, right away. I thought “No way, there’s just no way the Ring is that easy at 12.5x. Must be an out-of-focus star.” So I started working my way up in magnification, and sure enough, it was the Ring after all. I noticed the same thing again Saturday night. I couldn’t see much detail on most of the Messier objects at that magnification, but they just jumped out of the background starfields, even the smaller ones. If you like low-power scanning, this scope is a blast under dark skies and still a fun ride even under so-so skies.

Now, the not-so-hot:

• It’s hard to push the magnification, and I don’t like the result when I do. A 12mm eyepiece gives 128x in the Apex 127, 108x in the 90mm Mak, and 100x in the XT10, but only 33x in this  scope. A 6mm eyepiece gets you to 67x, but it ain’t worf it. The scope starts to pant around 40x and anything north of 60x is just bad. I noticed this the first night out, looking at Saturn and the moon, and it was still true this weekend. I don’t know if its astigmatism or poor collimation or what, but trying to achieve focus on planets is maddening. Jupiter goes from a vertical fan of red light on one side of focus to a horizontal fan of blue light on the other, and only sort of flirts with being a clean disk in between those extremes, at an infinitesimally tiny point that the rack-and-pinion focuser tends to shoot right past. It’s actually really puzzling to me that a scope that gives such clear, contrasty images at low power goes to crap so fast as the magnification goes up. (In case you’re wondering, we used exclusively low-power eyepieces with this scope for the Venus transit.)

So in the end the TS70 is kind of a one-trick pony. It is awesome for scanning around at low power and surfing the Milky Way. That’s the one thing it can do that neither of my Maks can. But unless you get a much better sample than I did, forget about doing any serious work at even moderate magnifications. The 90mm Mak is a much more versatile tool–it can do almost everything except widefield scanning. So at least the two small scopes complement each other.

Actually the awesome low-power views of the TS70 have inspired me. A small ED refractor like the Astro-Tech AT72ED ought to give equally good low-power views and be able to take magnification well, and could potentially put both the TS70 and the 90mm Mak out of business. I don’t know if it actually will, but I aim to find out. So I think one of those will be my next big astro purchase–once I save up for it.

In the meantime, since the TS70 performs like a superfinder anyway, I’m going to keep scheming on how to turn it into one. I’d love to have it mounted side-by-side with the Apex 127, so I’d have a rich-field scope and a planet-killer on the same mount.

Pocket Sky Atlas–Since I started out in astronomy, the PSA has been essentially the only atlas I’ve used. It has stars down to magnitude 7.6 and about 1600 deep-sky objects. That includes all the Messiers, all the Caldwells, and all the Herschel 400s, plus another thousand or so, so it’s covered my needs and then some. The only time I’ve printed up my own finder charts has been for hunting quasars. I haven’t felt the need to move up to a “deeper” atlas until very recently.

I started thinking about a deeper atlas after observing with Terry Nakazono last month. His most-used atlas is the Observer’s Sky Atlas, which covers the whole sky to mag 6 but also has enlarged charts to mag 9 for finding 250 deep sky objects, including all the Messiers. He also prints out detailed finder charts from the Tri-Atlas (a huge free atlas in three versions: mag 9, 11, and 13). He was surprised that I’ve gotten along as well as I have with just the PSA.

Part of the difference in preference probably has to do with the instruments that we use and how we get on target. Terry’s most-used scope is the SkyScanner 100, which has a red-dot finder. So he gets in the neighborhood–or closer, sometimes you can really bullseye things with an RDF–with the dot finder and then star-hops to his targets at the eyepiece. In contrast, I use a 9×50 RACI finder on whatever scope I am observing with (I only have one, and just move it around among scopes), and do almost all of my star-hopping with the finder alone. The 50mm finder does not go nearly as deep as the 100mm reflector–it simply shows fewer stars–so I often use the geometrical method of centering the finder on an unseen target (this is detailed by Harvard Pennington in The Year-Round Messier Marathon Field Guide and by Stephen Saber in his post on “sharpshooting” deep-sky objects–search for it here). I hadn’t given this much thought before Terry brought it up, but my less-deep atlas suits my finder-driven navigation, whereas eyepiece starhopping really requires that you be able to see as many charted stars as possible to keep from getting lost. So we have each gravitated toward the atlas that best suits our observing style–or rather, I started with PSA and never had a reason to gravitate away.

Until now, that is. The problem is not that the PSA doesn’t show enough deep-sky objects. I’ve only seen about a fifth of its 1600 plotted DSOs. The problem, as Terry pointed out, is that it just doesn’t show enough stars, at least for some problems. In trying to track down some of those small open clusters in Cygnus and Cassiopeia, I found that the plotted symbol in the PSA covered a good-sized field that was striped and mottled with star chains and asterisms of the summer Milky Way. The geometrical relationships shown in the PSA just weren’t enough. I couldn’t go to “the” cluster of stars that made an equilateral triangle (or whatever) with the nearest guide stars, because there half a dozen plausible candidates (actually, this might be a not-enough-DSOs plotted problem as well as a not-enough-stars problem). I need to see some of the fainter stars in between plotted on the chart, to break up those rich starfields into manageable–and interpretable–chunks.

So, to make a long story short, I ordered the first volume of Uranometria 2000.0, a mag 9 atlas, and I’ll get the other two volumes as funds allow. Stay tuned.

Observing report: All-nighter on Mount Baldy

Whew! Last night rocked. Terry Nakazono was out from LA, and we had been planning for about two weeks to spend the night observing up on Mount Baldy. We had made a shorter, half-night run up the mountain back in June, Terry to chase faint galaxies with his SkyScanner and me to log a few Herschel 400 objects with the XT10. Last night was basically the same plan, but on steroids–the moon was rising later, and neither of us had anywhere to be today. My wife and son were both out of town, she on work and he on a sleepover, so I was released on my own recognizance.

We got up there about 8:45 and met fellow PVAA member Craig Matthews setting up his 8″ Dob. Former PVAA president Ron Hoekwater joined us a little later on.

Terry was rolling with his SkyScanner again, and aiming for galaxies in Ursa Major and Bootes. I decided to leave the XT10 at home and take the Apex 127 Mak instead. I’ve had that scope for about a year, but before last night I had not really tried it out under dark skies. It did go to the Salton Sea in February, but we were mostly clouded out that night. Five inches is a lot of aperture under dark skies, and I was anxious to see what the Mak could do. Mount Baldy is not stupid-dark like Afton Canyon or western Arizona, but it’s not bad at all. The Milky Way was prominent and showed a fair amount of detail, especially after midnight when a strong marine layer at lower altitudes effectively halved the light pollution to the south (Inland Empire) and southwest (Los Angeles). On light pollution maps Baldy shows as being in the Orange zone, Bortle Class 5, but between the altitude and the marine layer it is sometimes effectively Green (Bortle 4). Last night was such a night.

I also took along the Celestron Travel Scope 70, which I had otherwise only used for quick peeks from my driveway. I’ve been meaning to blog about that scope. Right now you can get the scope, finder, two eyepieces, a tripod, and a backpack carrying case from Amazon for about $70 shipped. The finder is a travesty–an all-plastic “5×20″ unit that is in fact stopped down to 10mm right behind the objective. I stripped the so-called optics out of mine and use it as a naked-eye sight tube, in which role it performs admirably, and a heck of a lot better than it ever did as a magnifying finder. The tripod is a joke, the sort of thing that gives other flimsy tripods a bad name. It struggles to hold a point-and-shoot digital camera steady, let alone a telescope, so I donated it to a museum. But the eyepieces are serviceable, the carry bag is fine, and the telescope itself is okay–more on this in the next post–so for $70 it is a screaming deal. As with the Apex 127, I was anxious to see what it could do under dark skies.

It was not yet fully dark when we arrived so I spent some time jawing with Craig. It was cloudless and clear where we were, but we could tell it was raining in the Mojave Desert, because the northeastern sky flickered with distant lightning. And we knew it was far off because we never heard even a hint of thunder. The lightning was not reflecting off clouds but off of the sky itself. It was as if the sky was on the fritz, like a bad florescent bulb. It was a profoundly weird and unearthly effect.

I started my observing run by putting the Apex 127 on Saturn. In addition to observing with “new” scopes, I was also rolling with genuinely new eyepieces. Explore Scientific has been having a CUH-RAY-ZEE sale on their well-reviewed 68, 82, and 100-degree eyepieces, so I sold some unused gear and bought a few: the 24mm ES68, which delivers the widest possible true field in a 1.25″ eyepiece, and the 14mm and 8.8mm ES82s. The Apex 127 is my longest focal length scope at 1540mm, so those eyepieces yielded 64x (24mm), 110x (14mm), and 175x (8.8mm). I also have a 6mm Orion Expanse that gives 257x–that is my default high-mag eyepiece in any scope. The ES eyepieces had just arrived in the mail last week so last night was my first time to try  them out.

Anyway, the seeing was limiting, with the view shaky at 175x and downright ugly at 257x, but Saturn was crisp and jewel-like at 110x and I could see four moons even at 64x. I haven’t checked the charts to see for sure which ones they were, but Titan certainly, and Dione, Rhea, and Tethys probably. I have seen up to five moons of Saturn at once before, but that requires steadier skies than we had last night.

After Saturn I hit a few favorite Messiers, including the globs M13, M5, and M4, all of which were impressively resolved for a 5″ scope. My favorite view of the evening through the Apex 127 was of the galaxies M81/M82 in the same field at 64x, with tantalizing hints of detail visible in both.

Then I got to work, finding and logging Herschel 400 objects. I was chasing mostly open clusters in Cygnus and Cassiopeia. I logged NGCs 6866, 7062, 7086, 7128, 7008 (a planetary nebula) and 7790. I also tried for open clusters NGC 7044 in Cygnus and 136 in Cassiopeia, but could not locate anything I felt comfortable calling a definitive open cluster at the charted locations amid the rich Milky Way starfields. This was also an issue with several of the Cygnus clusters I did log—at high magnification they tended to disappear into the surrounding star chains and asterisms.

Getting skunked is no fun, and by that time I’d been working on H400s for about two hours. For a change of pace, I switched over to the Travel Scope 70 and started plinking at Messiers. With a 32mm Plossl eyepiece I got 12.5x magnification and a stunning 4-degree true field–more like a finder on steroids than a telescope. I started with the Double Cluster as soon as I saw it was over the horizon, then hit M31, but didn’t immediately see its satellite galaxies. Then it was on to the “steam” rising from the teapot of Sagittarius: M8, M20, M22, M24, M25, M23, M18, M17, M16—these last three all nicely framed in the same field—M26, and M11 up in Scutum. Then back to the “bottom” of Scorpio and Sagittarius to catch M6 (M7 had already set behind a hill to the south—bummer), M69, M70, and M54, then all across the sky for M51, M101, M102, M13, M92, M15, back to Andromeda for a nice view of M31, M32, and M110 all prominent in the same field, M52, M103, M33, M76, and M34. I’d seen all these things before, but for most of them this was the lowest magnification I had seen them at, given that my binocular observations of them had mostly been with 15x70s. One of my favorite views of the night was M103 in Cassiopeia with NGCs 654, 663, and 659 in an arc below in the same field.

A little after 3:00 AM it was time for another goal: tracking down the outer giants. I had looked up the finder charts for Uranus and Neptune on Sky & Telescope’s website and logged their positions in my atlas. I found Neptune first, in Aquarius, using the Apex 127. Neptune was a very blue spark, and required 257x to appear non-stellar. Uranus, farther east in Pisces, was obviously non-stellar even at 64x. I also ran up to 257x on it, but the most pleasing view was at 175x. I had seen both planets before, but never as well, nor spent as much time on them as I did last night. Very strange to see giant Neptune as a tiny point of light in the mind-boggling darkness and immensity of space.

After observing planets I went back to the TS70 to continue the Messier survey. Logged M57, M56, M27, M45—absolutely stunning in the center of the field at low power—M72, M73, M2, M30, M75, M71—and old adversary from my early days with the XT6, but dead easy at low mag under dark skies—and M77. I tried for the faint face-on spiral galaxy M74 and suspected something there but couldn’t be sure. For a few these objects, including M72 and M77, I had to go up in magnification to pull them out of the skyglow or make sure they were not stars, using the 25mm (16x) and 17mm (23.5x) Plossls. I tried the 24mm ES68 but it was too heavy for the long cantilever from the mid-tube dovetail to the extended focuser tube of the TS70.

The last big show of the night was an upside-down kite shape rising in the east, with Jupiter at the top, Venus at the bottom, the thin crescent moon on the left, and Aldebaran on the right. I looked at the planets with the Apex 127 at 64x—the near-horizon seeing was bad but Venus’s crescent shape was well-defined, and Jupiter showed a couple of cloud bands and of course the four Galilean moons. Update: Pictures of this conjunction are posted here.

And that was it. The sky was rapidly getting brighter in the east, so we didn’t need artificial light to pack up. We pulled out at 5:25, went to Norm’s diner for breakfast, and I dropped Terry off at his hotel and went home for some badly-needed rack.

My final tally for the night was 8 new H400s, including NGCs 654 and 659; 44 Messiers, 42 of which I saw in the TS70; and 5 planets, including all four gas giants and Venus. Favorite observations were the flashing sky from over-the-horizon lightning, M81 and M82 in the same field in the Apex 127, M31 and both satellite galaxies in TS70, my best-yet views of Neptune and Uranus, and the dawn conjunction of planets, moon, and stars. Between dusk and dawn I observed five of the seven planets visible in a 5-inch scope, missing only Mars and Mercury (both were achievable, it turns out, I just didn’t try for them). It was a heck of a good night.

How did all the equipment perform? Stay tuned for the next post!

Guest post: A few thoughts about the Orion SkyScanner and other scopes, including the Bushnell Ares 5

Here’s the first guest post by frequent commenter and dedicated deep-sky observer Terry Nakazono. Actually “dedicated” is an appalling understatement, since Terry regularly challenges himself and his scopes by (1) observing faint deep-sky objects, mostly galaxies, (2) with small scopes he can carry on public transportation and by foot, (3) from light-polluted skies in and around Los Angeles. I’ve been looking forward to reading about Terry’s scopes and his observing techniques, so this guest post is most welcome–hopefully there will be more to follow.

I’ve been using the Orion SkyScanner the past 2 years for nearly all of my deep-sky observing needs because it’s so easy to transport and set up – crucial if you rely on public transport and your own two feet to get to darker sky sites. For a package weighing in at 6.2 lbs with scope and mount combined, 100mm of mirror is a lot of aperture.

Both scope and mount fits snugly in this Adidas Schmidt backpack. All that’s needed is a tripod to attach the mount to, and a solid Manfrotto weighing in at only 4.5 lbs. (but with a 15.5 lb. weight load capacity) provides a strong, stable support.

Factor in the eyepieces, star charts and other accessories, and you’re only transporting about 12-13 lbs. of equipment on your body. By comparison, the Orion StarBlast 4.5 weighs 13 lbs, while the Orion SkyQuest XT4.5 is 17.6 lbs. Both cost about twice as much ($199.99 and $239.99, respectively) as the SkyScanner ($109.99) and both add only 14mm of additional aperture to the mirror. As Joe Roberts says, you will not likely find a scope that will show more for the cost.

For deep-sky work, superb optics isn’t as critical compared to planetary and double star work, so a 100mm Newtonian reflector works well (for me). Despite not having a collimatable primary mirror, collimation can be achieved by center spotting the primary mirror and adjusting the tilt on the secondary with the help of a collimation cap, significantly improving the views of the planets and double stars as well as deep-sky objects.

Here, you can just see the notebook reinforcement ring I put on the center of the primary mirror; the secondary mirror is collimated by adjusting the three allen screws surrounding the main screw in the center of the secondary holder with an allen-head screwdriver.

Having said all that, I’m no longer wedded to the SkyScanner as my sole dark-sky instrument.

I now have an Orion shoulder bag that I can carry my Orion VersaGo II mount and Bushnell Ares 5 in.

I also have a Vixen Mini-Porta mount which will support my Celestron C90 Maksutov-Cassegrain (C90Mak, top) and Orion ShortTube 80-A (ST80A, bottom) telescopes. I just ordered a smaller Orion shoulder bag that will carry the aforementioned mount and one of these two scopes. These Orion bags are ergonomically well-designed and make it easy to carry both scope and mount over your shoulder without causing major strain.

I suspect that despite their better optics, both the C90Mak and the ST80A will not allow me to see “deeper” into space (i.e. detect fainter objects) than the SkyScanner. But I’ll need to perform a “shoot-out” between these scopes outside of light-polluted urban skies to confirm.

Right now, I see the collapsible tube Bushnell Ares 5 (BA5) as the scope that will eventually replace the SkyScanner as my deep-sky instrument once I’ve gone as far as I can with the latter. This is an F/5 130mm Newtonian which thanks to its unusual design, weighs only about 6.5 lbs. for the OTA. At only $164.99 (with no shipping or sales tax) from Optics Planet, this is probably the best scope deal in the country right now.

Here is the scope with the tube collapsed, mounted on an Orion VersaGo II (because of its bulkiness, I’ve discarded the 6.5 lb. tabletop mount that came with this scope).

And here is the scope with the tube extended all the way out.

I’ve created a light shroud made out of black felt to cover the open tube and protect it from the elements while observing.

In the limited amount of time I’ve used this scope in both light-polluted and semi-dark skies, I’ve had a tantalizing taste of what 130 mm. of light gathering power can show. In my light-polluted front driveway with direct vision, I was able to see the ring shape of M57 for the very first time, using only 65X magnification. With the 100mm SkyScanner, I can barely make out shading within the interior of the oval-shaped disk at 80X or more using averted vision in darker skies. Less than two months ago, I took my BA5 out to a semi-dark (orange-zone) site for the first time. M13 looked nothing like the views I saw through the SkyScanner – at 130X, this globular was just exploding with stars all over the place. Ditto for M5.

As Matt has shown us through his reports on using “Stubby Fats” in the desert, you can do some serious deep-sky observing with a 130 mm F/5 Newtonian in semi-dark or dark skies.

But the BA5 has to wait until I’ve exhausted all the possibilities of the 100mm F/4 SkyScanner.

SkyWatcher 90mm Maks sold out?

Seems to be the case. Amazon has no more, and neither do Adorama and OPT.

So what to do if you’re in the market for a little Mak? Get a C90, stat! As Ed Ting said in his 3-way Mak comparo, “An embarrassingly good telescope package for almost no money. As of this writing they’re practically giving them away. If you’ve been thinking about getting one of these, I urge you to do so immediately before they run out, or before Celestron stops making them.”

On one hand, there is probably little danger that Celestron will stop making them; they’ve had a 90mm Mak in their product lineup for almost as long as I’ve been alive. Now that the SkyWatcher brand has been subsumed into Celestron (both are owned by Synta), it’s likely that the SkyWatcher-branded stuff is being allowed to die off to strengthen the Celestron brand.

On the other hand, C90s have been around for ages in multiple guises, but they haven’t always been this inexpensive. I wouldn’t get one just because they’re cheap–that way leads to a garage full of telescopes–but if you already want a little Mak and you’re bummed that the SkyWatchers are gone, the well-reviewed C90 should be a more than acceptable substitute.

I haven’t posted any new observations with my little Mak in a while because it’s been raining here. Next weekend I’m out of town, so I was hoping to get out to the desert for a Messier Marathon this weekend. Naturally it rained all weekend and today dawned sunny and clear. So it goes.

The King of Planets courts the Goddess of Love

For the next few nights, Jupiter and Venus are going to be as close together in the sky as they’ll get this year. I took this picture this evening from my driveway with my old Nikon Coolpix 45oo, about a 1 second exposure. Jupiter is on the left.

If you have optics, even small ones, you should be able to see the moons of Jupiter and see that Venus is a half-lit D-shape instead of a round ball of light.

I was out for a bit this afternoon and again this evening with the 90mm Sky Watcher Mak. I am learning to live with the finder, and the scope itself continues to impress. This is one of the sharpest bird photos I have ever taken:

The seeing was better tonight than it has been in a long time. I put the little scope on Jupiter and dropped in a 6mm eyepiece for 208x. Jupiter was razor-sharp and zebra-striped with cloud bands. In the steadiest moments, the South Equatorial Belt showed a ragged edge, and a small white storm notched its southern border. It was one of the most mesmerizing things I have ever seen with a small telescope.

As always, I am amazed that a little hunk of metal and glass the size of a 2-liter bottle can do so much. I have really missed having a little Mak around, and I don’t intend to be without one again.

Sidewalk astronomy with SkyWatcher Mak 90

I took the little SkyWatcher Mak downtown tonight to do some sidewalk astronomy. I haven’t blogged about sidewalk astronomy in a long time because I haven’t done any in a long time. And that’s been bumming me out. I was away from it for too long.

I got started doing sidewalk astronomy back in 2009, as part of the global 100 Hours of Astronomy event during the International Year of Astronomy. It’s a pretty straightforward gig: take a telescope to a public space and give passersby free looks at stuff in the sky. The moon and planets are good targets, because people are familiar with them (not everyone knows what the Pleiades are), they’re naked-eye visible so you can point them out to folks, they punch through city light pollution just fine, and they look great in small telescopes. I know some sidewalk astronomers take big telescopes, and more power to ‘em, but I have found that my inclination to go do it is proportional to the size of telescope I have to lug downtown (about five blocks from my house).

For the first long while, my sidewalk scope was my original 90mm Mak, the Orion Apex. It was perfect for the job: compact, lightweight, able to be set up and torn down in about one minute on either end, sharp optics, easy for newbies to focus… Then one night at an astronomy club outreach I reach out in the dark and turned the wrong knob on the mount, and dropped the telescope. On the way down it hit a tripod leg and my foot, but neither absorbed enough energy to keep it from hitting the ground pretty hard. The impact spalled a bit of coating (at least, and possibly some glass underneath it) off the primary mirror. I sold it cheap to a fellow amateur who thought it was salvageable.

My next sidewalk scope was another 90mm Mak, an old orange-tube Celestron C90. I had always wanted one, ever since I saw my  first telescope catalog back at age 12. They are sweet little scopes, build like tanks, and since they focus with a rotating barrel like a camera lens there is not much that can go wrong with them; if the focuser ever gums up you just unscrew the front part of the tube, re-lube the threads, and screw it back together.

It turned out, though, that I liked the idea of the C90 better than the actual thing (this was a far different beast from the modern C90 that is on sale at Amazon and elsewhere). The rotating barrel sounded good in theory, but in practice it was a huge pain to focus the scope while keeping it pointed at an object, especially at moderate to high powers, and especially for people with no experience. I used the C90 for sidewalk astro once or twice and then sold it.

(Aside: one of these days I’ll blog about the joys of buying and selling used telescopes. The bottom line is, scopes hold their value pretty well. If you are judicious and buy used you can usually sell them for what you paid for them, so once you’ve ponied up the initial investment you can essentially try out new [to you] gear for free.)

Then I went through a phase of doing sidewalk astro with bigger scopes: a 5″ f/7 reflector on a homemade mount, a 5″ f/5 reflector (Stubby Fats), and an 80mm f/11 refractor (Shorty Long). These are all fine scopes for showing people stuff in the sky, but not so hot for having to lug five blocks. I needed a dinky scope, something bigger than my 50mm refractor (which is too small for that kind of work) but smaller than my other scopes. Frankly, what I needed was a 90mm Mak, I’d just put myself in the position of not having one.

Until now. Suitably armed with the SkyWatcher Mak, I went forth into the warm spring night, and between 7:35 and 8:45 I showed 48 people the moons of Jupiter. The seeing was godawful, as bad as I have ever seen it. Jupiter was a visibly waving ball of fire, when normally I can see at least half a dozen cloud bands (as shown in the previous post). But the Galilean moons were all visible, strung out in a ragged line to the west of king of planets, and everyone who stopped to look seemed bowled over by the views, so who am I to complain?

I didn’t take the multi-mount that came with the scope, just the little Universal Astronomics DwarfStar alt-az mount that I used to use with the old 90mm Maks (shown in the picture at the top of this post). I left the finder and diagonal on the scope, put it nose down in the included backpack, put spare eyepieces in the side pockets, put all that on my back and carried the folded tripod and mount in one hand. It was great, just like old times.

John Dobson argues that the only measure of a telescope’s value that is worth a damn is the number of people who have looked through it. By that metric, I reckon this little Mak may end up becoming my most valuable scope. I’ll keep you posted!

SkyWatcher Mak 90–more pictures, and using the mount in manual mode

More pictures of the SkyWatcher 90mm Backpacker Mak-Cass. Yesterday I took the multi-mount off its tabletop base and put it on my Manfrotto tripod for some digiscoping. I was using it without the power on, as a manually-aimed alt-az mount.

Another of those down-the-tube shots showing the optics. The point of this photo is different, though. Check out the knurled knob on the left that tightens the dovetail. Usually these just have a fat set-screw that goes straight onto the scope’s dovetail bar, and tightening that screw puts a tiny dent or ‘bite’ into the dovetail bar. On this mount, though, the set-screw bypasses the scope’s dovetail bar, and turning the hand knob tightens a broad metal clamp (the silver bit just underneath the hand knob in the above photo) that grips the dovetail bar along its entire length. So the scope is held more securely, and there’s no bite mark on the dovetail bar. Very nifty–I wish more mounts had this.

The big news about using the mount manually is simply that it can be used that way. You don’t want to manually aim the scope once the power is on, or you risk damaging the gears inside the mount, but as long as the power is off you can just grab the tube and point.

A close-up of the back end showing, from left to right, the Astro-Tech dielectric diagonal and 32mm Plossl I was using for birding, the six-screw  mount for the little 8×20 optical finder, and the dovetail clamp and adjacent latitude/altitude scale on the mount.

Getting lined up on a distant bird using the optical finderscope. Imagine that the mount was sitting on its tabletop base and that you were trying to find something high in the sky–eventually there is just no room to get your head behind the eyepiece of the finder. That’s why I strongly prefer RACI–right angle, correct image–finders, which orient the finder eyepiece in the same direction as the telescope eyepiece, so you can look down and in from above.

Waiting for the fall of night.

My two best shots of Jupiter with the little Mak. I could see about half a dozen distinct cloud bands at the eyepiece, and for once the photos bear that out. As usual, however, I could still see more detail at the eyepiece than the camera captured. The views are not as good as through the Apex 127–compare to the Jupiter photo here–but they’re not that far behind.

The waxing gibbous moon, again with the little Mak. This is probably the sharpest moon photo I’ve ever gotten with a 90mm Mak. This SkyWatcher scope is at least as good, optically, as the Orion Apex 90 I used to have. I don’t know yet if it’s as good as the Celestron C90, which has gotten stupid-good reviews, but I don’t think it will disappoint anyone. Last night the sky was still enough that I could run it up to 200x and the view was still razor-sharp. That’s 57x per inch of aperture, compared to the rough rule of thumb of 50x/inch in a good scope, so this little scope is punching above its weight. I haven’t tried to max out the magnification to see where it breaks down, but I think it will probably be quite a bit higher.

The fact that the meniscus is merely coated instead of multi-coated has not impaired the scope’s performance as far as I can tell. Possibly the few percent difference in light transmission will be noticeable when one can switch back and forth between this scope and one with a multi-coated meniscus; it is certainly not noticeable when using the scope on its own.

I still haven’t had time to try out the tracking function on the mount, but this afternoon I did put batteries in and slewed it around and didn’t have any problems. I’ll report back when I’ve had it out tracking under the stars.

The SkyWatcher 90 Backpacker on the moon and some birds

Fate smiled on me yesterday and early this morning, and I was able to get some pictures with the SkyWatcher 90 mm Backpacker. If you’re impatient you can scroll to the bottom of the post for the photos.

I should stop here and say that I ultimately intend to test the whole kit–scope, mount, and accessories–as a system, because whether you use it as-is or mix-and-match components, it is sold as a system and is at least theoretically supposed to function as one. However, between teaching, taking a statistics class, and wrangling ostriches, I just haven’t had time to mess with the mount. My primary concern has been to assess the optical quality of the scope–and now I actually have some information.

I got in a brief observing session between responsibilities yesterday afternoon. I was plinking around the yard, looking at birds. For these observations I started out using the included 90-degree prism diagonal and 25mm Plossl eyepiece. I first looked at a couple of obvious birds silhouetted against the sky in treetops, and they looked fine. Then I went after one hidden in the leaves and branches of one of my neighbor’s trees, and in those dimmer conditions I noticed something unnerving: the eyepiece view was very soft and didn’t snap to focus, as if I was observing with a very short focal ratio scope like an Astroscan. Also, there was some ghosting of the image in the eyepiece, and the edge of the image was poorly defined. In short, it was very, very different from the crisp, sharp, detailed images that Maks are renowned for, and not in a good way. I was just having a “Hey, what the–!” moment when I remembered where I had seen these kinds of problems before: in scopes using cheap prism diagonals instead of mirrors.

Without moving the scope, I went to the garage and pulled the Astro-Tech dielectric diagonal off my Apex 127, and swapped that out for the prism diagonal. I held my breath as I put my eye back to the eyepiece–were the problems all in the diagonal, or had I gotten a lemon of a scope?

Sweet relief–even in the dim light amongst the leaves and branches, the view was razor-sharp and contrasty. It was like someone had run a very good image-sharpening algorithm on the eyepiece view. Suddenly details that were invisible before were popping out all over the place. Leaves that had been too fuzzy to invite close inspection were etched with delicate networks of veins. The whole view just looked more real.

I decided then that I would try to find out just how good or bad the prism diagonal is, and under what conditions.

After that quick peek I didn’t get another chance to use the scope until about 10:00 last night. The first quarter moon was still fairly high in the west, but the seeing was not good. The air just roiled over the moon, and every star I looked at scintillated with fast-moving rays of light. Not good conditions for testing a new telescope, because it’s hard to push the magnification up and tell if the results you’re getting are because of the scope, the seeing, or both. But I went ahead and put the scope through it’s paces anyway. The thing about seeing is that from time to time it does settle down a bit, at least momentarily, and in those instants the amount of additional detail that is visible is sometimes shocking. So the longer you look and the more patiently you observe, the more likely you are to catch those rare moments of steadier air and see something really remarkable.

For eyepieces I used a 32mm Sirius Plossl from Orion and the 12.5mm and 6.3mm SkyWatcher Plossls that came with the scope. I took all of the pictures in this post afocally with a Nikon Coolpix 4500 hand-held to the 32mm Plossl, and with the camera optically zoomed enough to eliminate any vignetting.

The moon looked surprisingly good with the Astro-Tech diagonal in place. It was fairly swimming in the turbulent air, as if being viewed under a thin stream of moving water. But if I focused on a particular crater or feature for the space of a minute or two I would catch a patch of calmer air and see perhaps double the detail in those brief glimpses. Small craters that were otherwise just spots would pop into focus with dark rims and bright floors. The 12.5mm eyepiece had tighter eye relief than I am used to in that focal length; I have long-ish eyelashes and they were occasionally brushing the eye lens, something I don’t remember ever happening with the 12mm SkyWatcher Plossl that I got with Shorty Long, my 80mm f/11 achromat. That 12mm looks identical to the Orion Sirius line, whereas the eyepieces that came with the Backpacker have smooth silver barrels and no rubber eyecups, so even though they are both branded SkyWatcher they might have somewhat different guts. Also, I’ll have to look more closely the next time I’m out, but the 12mm felt like it had a narrower apparent field of view than the 32mm, which shouldn’t be possible if they are both Plossls, which typically yield a 52-degree apparent field. Could be that the short eye relief was playing tricks on my perceptions. Anyway, with the 12.5mm EP in the scope was working at 100x and I was still seeing plenty of few detail in the still moments.

I put the 6.3mm EP in just for the heck of it. I wasn’t expecting much, both because of the punk seeing and because that magnification–200x–ought to be pushing on the edge of what this scope can do. A commonly used rule of thumb is that a good scope should be able to handle 50x per inch of aperture. At 3.5 inches, any of these 90mm Maks ought to be good up to at least 175x. But I have to point out that the 50x/inch “rule” is often broken and not only by premium scopes. David DeLano has had his 114mm reflector up to 400x (89x per inch), and the other night I took my Apex 127 to 514x (103x) to split a close double star that was not split at 257x. I’ll just note that those are both relatively long focal ratio scopes, about f/8 for David’s reflector and f/12 for the Apex, and maybe that has something to do with it; such gently-tapering light cones are certainly easier on eyepieces and so on. Anyway, at 200x with the 6.3mm EP I was still getting glimpses of considerable detail. I can’t say for certain because of the lousy seeing, but I think this scope can handle 200x. I hope I get a still night soon to test that.

Okay, so far so good with the Astro-Tech diagonal. I swapped it out for the stock prism diagonal and went back to the 32mm Plossl. YUCK! I almost could not focus my eye on the moon, because there was a moon-sized ghost image floating around in the field of view that looked like it was probably some kind of reflection of the primary mirror or maybe even the corrector. It was a big white donut with a dark hole in the middle, anyway. I’ll stress that this ghost image or whatever it was was not there with the Astro-Tech diagonal. I have never seen anything quite like it before, and given the controlled conditions of time, place, observer, scope, and eyepiece, I feel confident blaming the prism diagonal.

I tried the two other eyepieces. The ghost didn’t show up in either of them. The 12.5mm was merely okay, producing a slightly softer view in the prism diagonal than in the Astro-Tech. The 6.3mm was very noticeably softer; this time going from 100x to 200x looked and felt like empty magnification.

I also looked at Belelgeuse and Mars with all combinations of diagonals and eyepieces. Betelgeuse was sparkling in the Astro-Tech diagonal, but at least the scintillating rays of light were sharp. In the prism diagonal it was a fuzzy mess. Betelgeuse was down near the horizon, though, and Mars was very high, so I hoped to see at least some detail on good old Barsoom.

Mars really required the 12.5mm EP; at 39x it was a bright orange BB, too small to see detail on, and at 200x it was a big orange smudge. At 100x with the prism diagonal I could only suspect the polar cap, and that might have been because I knew it was there to be seen. I had started that run with the Astro-Tech, and in steadier moments the polar cap was a well-defined white patch with a hair-fine black border. In brief flashes I also saw dark markings on the face of the planet’s disk. So despite the lousy seeing, the little scope lived up to the Maksutov reputation as a fine planetary instrument.

I did see some off-axis glare from Betelgeuse and Mars, but only in the 32mm Plossl. I am going to do some more testing to see if that is a scope issue or, as I suspect, an eyepiece issue. Also, getting the scope on target using the 8×20 straight-through finder was not difficult but it was uncomfortable, and usually required me to move my chair, squat behind the scope, and go back and forth between sighting down the tube and squinting through the finder. It’s doable, it’s just not fun, and something like a 6×30 RACI should be a high-priority upgrade if you get one of these.

This morning before work I got some photos of neighborhood birds, using both the Astro-Tech dielectric diagonal and the prism diagonal that came with the scope. Be aware that that both my camera and my photographic method are primitive. The camera is a 4-megapixel job more than a decade old now, and while its rotating barrel design is convenient for digiscoping, it just can’t keep up with the better modern cameras. Also, hand-holding the camera to the eyepiece means that I’m usually the most mobile link in the system, so any fuzz or blurring in the photos is possibly caused by my minuscule shakes rather than by the optics. To try to eliminate that factor as best I could, I took several exposures of each target and picked the sharpest from each set for the comparison images. In all of the comparisons between diagonals, the photo through the prism is on the left, and the dielectric photo is on the right. Other than having been put into the same image for comparative purposes, the photos are completely unprocessed: no sharpening, no levels or curves, no rotation, and I didn’t even flip the photos through the star diagonal, which are reversed left-to-right. Click each image for the original, full-resolution version.

The moon last night. The view through the dielectric diagonal was markedly sharper and more contrasty, and these unprocessed photos, taken just minutes apart, bear that out. The full-resolution dielectric photo shows a very thin line of purple chromatic aberration around the limb of the moon, but I couldn’t see it at the eyepiece despite being on the lookout for it.

This fellow was sitting a tree that I have paced out at about 70 yards from my driveway. Again, the dielectric photo (right) has better contrast, and look at the difference in the color of the background sky. This is the same bird and I took the photos about 2 minutes apart.

This dove was quite a bit farther way. I haven’t paced it out, but this powerline must be well over 100 yards from my driveway. Notice the scale of the bird in the photos and the pronounced drop-off in detail compared to the little songbird above. Detail is probably a wash here, but the dielectric photo has better contrast and again the background sky is more blue.

One more point to make is that I hardly ever post raw images. Almost every photo can benefit from a little processing with Unsharp Mask and Curves (I use GIMP, which is free–see details on what I do to each photo in this post). Here are the best dielectric photos of the moon and the songbird, with the unprocessed photo on the left and the lightly processed version on the right (this time I did rotate the moon and flip it to its correct side).

So, what did I learn from all of this? The SkyWatcher 90 Backpacker is a decent little scope. I couldn’t see any optical problems, and I was impressed to see details on Mars at 100x with the included 12.mm Plossl and the Astro-Tech diagonal. Views of birds are as good as those I used to get with my Orion Apex 90. But the supplied diagonal is not good, and really limits the views the telescope is capable of providing. If you get one, replacing the diagonal with even an inexpensive mirror diagonal should be a top priority. Let me put in a plug here for the Astro-Tech dielectric diagonal. It consistently throws up a great image–it’s the diagonal I used when taking the Apex 127 to 514x for that double star split–but at $69.95 for the 1.25″ version it is no more expensive than some ‘entry-level’ mirror diagonals.

The supplied prism diagonal does have one potential use: if you have an old binocular laying around, you can disassemble it and use one of the objective lenses to make a proper finderscope, and if you include the diagonal it could even be a RACI. Mounting a bigger homemade finder to the scope will take some ingenuity, but I figure anyone who likes to tinker enough to build a finder in the first place can be trusted to come up with a mount as well.

So I now feel confident enough to recommend the scope, at least, although the mount is still a question mark and the diagonal and finder are troublesome (as expected). I don’t know how the scope performs compared to the Celestron C90, which is also on sale, because I haven’t had the chance to test them side-by-side. But with a little luck I may get that chance soon.

Hopefully this weekend I’ll have time to get the mount up and running. Stay tuned.