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.

Mission 21: Nova in Sagittarius

Mission Objective: Nova

Equipment: Binoculars, Magnifying Finder, Telescope

Required Time: 10 minutes

Related Missions: Not Everyone’s Pot of Tea

Just got this via email from Sky & Telescope:

A fairly bright nova has been discovered in Japan by Koichi Nishiyama (from Kurame) and Fujio Kabashima (Miyaki). They made their find on July 7, 2012, using a 105-mm f/4 camera lens and CCD, describing the nova as magnitude 7.8. It is located in Sagittarius roughly between the “lid” and “spout” of the Teapot stars, at right ascension 18^h 20.5^m, declination -27° 44′ (equinox 2000.0). A number of other observers in Japan have made confirming sightings.

The discovery was announced on CBET 3166, issued July 7th by the Central Bureau for Astronomical Telegrams in Cambridge, Massachusetts. This circular assigns the star the official designations Nova Sagittarii 2012 No. 4 and also PNV J18202726-2744263.

The American Association of Variable Star Observers (AAVSO) is requesting observations of this nova. The AAVSO collects magnitude determinations by skilled observers to aid in the study of novae and other variable stars, and their site offers guidance on the techniques involved.

Whether or not you go as far as submitting observations to the AAVSO, the nova should be fun to track down and a relatively easy catch. And, hey, since you’ll be in Sagittarius anyway, you’ll have plenty of other pretty things to look at after you find the nova.

Here’s a widefield finder chart I knocked up in GIMP, using this photo from Wikipedia. The green lines mark out the “teapot” asterism in Sagittarius–if you don’t know how to find this, check here. The box is the field shown in the closeup finder chart below. The nova is indicated by the white cross. The red arrow is not the nova, it’s a magnitude 4.7 field star that will help you orient the closeup finder chart.

And here’s the closeup finder chart, courtesy of the AAVSO’s free oonline chart generator. I added the arrow to indicate the same field star as shown in the above image (the arrow points the same way, too). This is rotated 180 degrees from the sky (for Northern Hemisphere observers looking south) and from the widefield finder chart above, so you can use it as-is in a Newtonian reflector or straight-through finderscope, or flip it around for binoculars or a right-angle correct-image (RACI) finder. If you have a refractor or Cassegrain scope and you’re using a star diagonal, you can use the AAVSO plotter to make a rightside-up but reversed chart to match what you’ll see at the eyepiece. Copy and paste the nova’s designation into the box and select the options you want: PNV J18202726-2744263.

And now I’m going to post this and go look for the nova myself. Happy hunting!

Update the next day (July 8): I found it. I had to do a lot of flipping back and forth between chart and telescope to make sure I had the right object–it looks just like another 7th magnitude star in the eyepiece. And actually I used the finder rather than the scope. A 10×50 finder (or just about any pair of binoculars) collects enough light to show the nova easily, and gives a wide enough field to make it easy to find. I was using the SkyWatcher 90mm Mak, which has a maximum true field of about 1.5 degrees–too narrow to show most of the surrounding stars I needed to use to orient myself (imagine plotting a cross-country trip on Google Maps if you couldn’t zoom out and only saw a 10-mile stretch at a time).

Anyway, in all of the back-and-forthing I figured out a couple of geometric relationships that helped me figure out which 7th magnitude star was the nova. The next two charts are modifications of the AAVSO chart that show these relationships. I stripped out all the stars fainter than 8th magnitude, and all of the clutter of magnitude numbers, and rotated the charts 180 degrees to match the view in binoculars or a RACI finder (from the Northern Hemisphere).

First, the 4th magnitude star (red arrow) that I use as my “anchor” in this stretch of Sagittarius sits at the top of a north-south chain of 6th and 7th magnitude stars, and makes a diagonal with the second-brightest star in the field. The nova is about midway along that diagonal line, just above and to the left.

That helped, but as usual I was nervous about whether the star I thought was the nova actually was, so I used another relationship to double check.

The “anchor” star forms a right triangle with the two closest semi-bright (~6th-7th magnitude) stars, and the nova is almost straight down from the left-hand (eastern) point of the triangle.

If you haven’t yet mastered star-hopping, that’s basically all there is to it–working from the chart to the finder and eyepiece, you notice little geometric patterns and work from big, bright anchors to fainter, dimmer targets. After a while, it gets to be reflexive. You learn to build in double-checks to keep from wasting your time on chance alignments of stars that are close to–but not exactly–what you’re looking. Your internal monologue might run like so:

Looking at chart: Okay, there should be an arc of four stars like an eyebrow about two degrees left of [bright star].

Looking through finder: Got it.

Back to chart: Hmm, if I follow that arc to right, I should find a triangle of faint stars that points to [target].

Looking through finder: Sweeping right…hmm. There’s a triangle of faint stars, but is it the right one? I should find [target] right over here, but…nothing there.

Back to chart: Okay, now I see that the triangle of faint stars I want is not just right of the “eyebrow”, but right and a bit down, and it has a pair of stars like eyes just to the south.

Looking through finder: Here’s the triangle I thought was the right one, but–nope, no pair of stars like eyes. Let me back up to the “eyebrow” and try again. Now this time I go right and a bit down…yep, all right, there’s another triangle of stars, there’s the pair of stars like eyes. Hmm. Still don’t see the target, but it’s a small galaxy, so maybe it’s just not showing up in the finder. It should be right about…here. [put finder cross-hairs where target should be]

Looking through eyepiece: Well, hello beautiful!

See the transit of Venus in Claremont

If no clouds come to spoil the fun, I will be in downtown Claremont this afternoon (Tuesday, June 5) with a scope set up for free public viewing of the transit of Venus. The transit starts at 3:06 PM, PDT, and will still be in progress when the sun sets at 7:59. I plan to be there for all of it. If all goes well, from about 2:50 onward I will be in the public square in front of the theater, on the northeast corner of First Street and Indian Hill Boulevard. Whenever the sun gets low enough to go behind the theater, I’ll head up to the top of the parking garage across the street, to watch the sun set with Venus still crossing the solar disk. You, whoever you are, are welcome to join me.

If by some freak chance it is cloudy this afternoon, I’m going to throw my gear in the car and run up to Big Bear, which gets more sunny days than almost anywhere else in SoCal (that’s why the solar observatory is there). In which case, you’re still welcome to join me, if you can find me. Try the Discovery Center on the north shore, if it’s sunny…or the nearest pub if it’s not.

Fingers firmly crossed for clear, sunny skies!

Awesome Venus transit simulator

In an earlier post I linked to a Venus transit calculator, which is pretty sweet, but now there’s an even better one. Here’s a screenshot:

You put in your location (latitude and longitude, or click the map) and it shows you a movie of the transit from your location with contact times and places (on the limb of the sun) and sunrise or sunset if those interfere. Very slick, and takes a lot of the guesswork out of setting up for the transit. It will even spit out screenshots with a button-click, which is how I got this one. Check it out.

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.

Yet another target of opportunity: Deep Sky Companions: Hidden Treasures by Stephen James O’Meara

I do have bigger ambitions for this blog than just collecting deals on astronomy gear from around the web, but this one might not be around for long, so here goes.

The short version, if you’re in a hurry: Stephen James O’Meara’s Hidden Treasures, the third volume in his Deep Sky Companions series from Cambridge, usually $46, is currently on closeout for $18.40 at Amazon. As of this writing, there are only seven copies left at the reduced price.

The long version: Stephen James O’Meara is probably the most respected visual observer of astronomical phenomena of anyone alive. His achievements are legendary. As a teenager, he saw and sketched spokes in the rings of Saturn. Professional astronomers dismissed the spokes as an optical illusion, because the differing rotation speeds of the rings would disrupt and smear out any radial linear features. Then the Voyager probes got to Saturn and, lo and behold, the rings did have spokes–probably electrostatically charged dust floating above the rings and rotating at the same speed as the planet. For most of us the planet Uranus is a dim blue-green dot if we manage to track it down at all; O’Meara saw white clouds on Uranus and mapped their progress to make the first-ever determination of the planet’s rotational period, which was unknown at the time as no space probes had yet made it to Uranus. Voyager II later confirmed O’Meara’s estimate. The list goes on–there’s a pretty good mini-biography of O’Meara in Timothy Ferris’s Seeing in the Dark that describes more of his exploits and achievements.

O’Meara might just have the best vision of anyone alive–at least, when his vision has been tested, it has been sharper and more sensitive than that of any other person who has ever been tested. These tests, by the way, have included having O’Meara sketch faint stars and then comparing his sketches to long-exposure photographs taken with giant telescopes; frequently O’Meara has been able to see things at the eyepiece that no one else can confirm, even when he tells them exactly where to look. (That must be frustrating!)

By all accounts, O’Meara is not only a tremendously accomplished observer but also a darned nice guy. In addition to the Deep Sky Companions series and his other books, he has written observing columns for both Sky & Telescope and Astronomy (and probably others I don’t know about), and his writing is always full of wonder at the night sky and encouragement for his readers to get out and see these things for themselves. One might expect the world’s best visual observer to put on airs and tell the rest of us lesser mortals what deep sky objects really look like. But O’Meara takes the opposite course. He always emphasizes that visual observation of the night sky is an intensely personal experience, presents his impressions of deep sky objects as just that, his impressions, and encourages his readers to get outside, see for themselves, and form their own impressions.

The Deep Sky Companions series now includes four books: The Messier Objects (1998, 318 pages), The Caldwell Objects (2003, 500 pages), Hidden Treasures (2007, 602 pages), and The Secret Deep (2011, 498 pages). The Messier and Caldwell volumes cover the 109 objects on each of those lists in detail. The newer volumes also cover 109 deep sky objects apiece, in homage to the Messier and Caldwell lists, but don’t represent formal observing lists. Instead, the objects are chosen by O’Meara to help observers find and explore some of the lesser-known gems of the night sky.

I haven’t yet seen The Secret Deep, but of the first three volumes, each is better than the last. The Messier Objects introduces the basic format for the series: each of the 109 objects in the book is the subject a multi-page essay that includes its observational history, mythological history (if any), current astrophysical understanding, and visual telescopic appearance, plus a black-and-white astrophoto and an eyepiece sketch by O’Meara. I can’t remember if this is true of the Messier volume–I don’t own it but have only borrowed it from the public library–but the later volumes all have star maps that show the location of each object. The Calwell Objects follows the same format, but the essay for each object is longer and more complete and there is a nice series of appendices, including 20 additional objects readers are suggested to track down and a mini-biography of William Herschel. The Messier volume is a fine book on its own terms, but seems almost skimpy in comparison to its longer sequels.

Hidden Treasures is better still. The star charts are larger and more detailed, the essays are longer and more absorbing, and there is more reference material at the back, including a multi-page table that shows the overlap between the objects included in the book and those on several popular deep sky observing lists, like the Saguaro Astronomy Club’s 110 Best of the NGC.  The mini-biography at the back is of Caroline Herschel, whose formidable achievements in astronomy have been overshadowed by those of her brother William and nephew John. Once again there is a list of 20 bonus objects for readers who want to go beyond the 109 objects covered in detail. The book is a beast, 600 pages long and about 4 pounds. The paper is glossy and the reproduction of the photos, drawings, and maps is very good.

One point of particular interest is an introductory essay in which O’Meara explains how he chose the 109 objects to cover in the book. There were three main sources: O’Meara’s own list of personal favorites, objects combed from several popular “best of” observing lists, and–most interestingly to me–historical lists from the 1700s. There weren’t that many deep sky objects known before William Herschel started his all-sky survey in 1782, and all of them are relatively bright and easy to see in small scopes (otherwise they would not have been discovered in the scopes available at the time), so O’Meara included all of them that aren’t on the Messier and Caldwell lists in Hidden Treasures. Therefore, if you have those three books, you have eyepiece descriptions, up-to-date astrophysical data, charts, sketches, and photos for every deep sky object in the northern skies (i.e., above -10 degrees) known before 1782. That’s pretty cool.

One more point of continuity among the books: O’Meara used a 4-inch refractor from the slopes of Kilauea in Hawaii to observe, sketch, and describe the visual appearance of all of the objects in at least the first three books (except for a few Caldwell objects in the deep southern skies). So observations and sketches among books are directly comparable, having been generated by the same person using the same scope under the same conditions.

I find it interesting and encouraging that O’Meara chose a small telescope to make his observations. Now, O’Meara has the best eyesight of anyone ever tested; his scope, a TeleVue Genesis, is one of the finest refractors ever made; and Kilauea has some of the darkest skies left on Earth. Nevertheless, there are hard physical limits to what a 4-inch telescope can show. O’Meara is humble and forthright in reporting his observations, and when he couldn’t see something–a dark lane in a galaxy, known gas filaments in a planetary nebula–he says so. Anyway, if objects are visible and detailed in O’Meara’s Genesis from Kilauea, they should be observable in commonly available 6- to 10-inch scopes in the more average viewing conditions experienced by most amateur astronomers. So the books are not reports of observations impossible for average stargazers, but guidebooks to help average stargazers make exceptional observations.

I’m happy to recommend all of the books in the Deep Sky Companions series (although I haven’t seen The Secret Deep yet, given the quality of the others I’m prepared to recommend it on faith). If you’re interested in the books, getting Hidden Treasures for less than twenty bucks is an opportunity to test the waters without stressing your wallet. It’s an engaging read on a cloudy night, an enlightening look at how scientific and popular knowledge of celestial objects has changed over the last three centuries, and a genuinely useful guide to finding and observing a host of bright deep sky objects beyond the Messier and Caldwell lists. I ordered a copy when I saw the discounted price, and I’m very, very happy to have it.

Don’t miss the moon and planets at sunset this weekend

From bottom to top: the moon, Venus, and Jupiter, on Feb. 24, 2012.

Venus and Jupiter are both high in the evening sky at sunset right now. Just look west right when it gets dark and they’ll be the two brightest stars in the west. Venus is the brighter and lower of the two.

For the next couple of nights they’ll be joined by the waxing crescent moon. Tonight the moon was just below Venus, so the three bodies were stacked up the sky from lowest and brightest to highest and dimmest.

Early next week the moon will pull away from the planets as it continues on its monthly eastward trek around the sky, but Venus and Jupiter will still be there and looking good.

A close-up of the moon at the same time as the photo at top.

Venus is slightly gibbous right now (between 4 and 5 in the diagram below). On March 26 it will achieve its greatest eastern elongation from the sun, 46 degrees, meaning that at sunset it will be halfway between the horizon and the zenith. At that point it will be half-lit as seen from Earth (5). From then on into April and May, Venus will get lower and larger as it goes into its crescent phase (6) and gets ready to pass between the Sun and the Earth. Venus makes that passage all the time as it transitions from being the evening star (east of the sun as seen from Earth = above the western horizon at sunset, 6 in the diagram) to the morning star (west of the sun as seen from Earth = above the eastern horizon at sunrise, 1 in the diagram).

Phases of Venus as seen from Earth

Because the orbits of Earth and Venus are not precisely in the same plane, Venus does not usually pass directly between the sun and the Earth but passes above or below the sun as seen from Earth. This time will be different; as happens only a couple of times per century at most, the orbits are lined up just so and Venus will pass across the face of the sun as seen from Earth. That’s the transit of Venus I’ve been so het up about. Stay tuned for more on that, and keep looking up at sunset for the next few weeks to see Jupiter and Venus continue their tango.

More crazy scope deals at Amazon

I honestly can’t figure out why I haven’t blogged about this sooner. As happens from time to time, right now there are some screaming deals on scopes at Amazon. The two best are 90mm Maksutov-Cassegrains, a rugged, portable design that has been popular for decades.

The first is the Celestron C90. This scope has been around under the same name since the 1970s, but with three different designs. The first incarnation was a short, all-metal job sold in orange or black livery–you can see the orange-tube version I used to own on the left-hand tripod in this photo–that you focused by rotating the barrel, like a camera lens. The second incarnation was a longer, rubber-armored version more obviously intended to be used as a spotting scope, still with the rotating-barrel focusing mechanism. That one seems to have been discontinued just a few years ago in favor of the current version, which is a very attractive near-clone of the 90mm Synta Maks sold by Orion and SkyWatcher, with a more typical focusing knob at the back. There are differences among the models but they are mostly cosmetic, and the optics for all three brands are made by Synta.

This latest version is the one currently on sale at Amazon. I’ve been watching it for a while and prices have been all over the map, from a low around $140 to a high around $200. For reference, Orion’s StarMax 90 TableTop has an undiscounted retail price of $200 ($210 shipped) so for the sake of this post I’ll define a good deal as anything under $200. As of this writing the C90 is going for $172 with free shipping, which is a steal. UPDATE: OPT has this scope for $179.95 with free shipping right now (Feb. 26, 2012), so if Amazon is out or the price has gone up, check OPT. I’ve bought three scopes from OPT and the customer service has been outstanding, so I’m always happy to send them business. I know the scope is also on sale at other places around the web, but so far I haven’t found any deals as good as Amazon and OPT have on this scope–please let me know if you find a better one!

Most importantly, the C90 has gotten very good reviews, both at Ed Ting’s telescope review site and on Cloudy Nights. Some of the photos of Jupiter taken with these scopes are just astonishing–see this and this (NB: I think both of these are not single exposures but stacks of multiple frames, which brings out more detail).

The other crazy good deal right now is the Sky Watcher 90 mm Backpacker, which is the same tube as Orion’s Apex/StarMax 90 on a tabletop tracking mount. The mount can be put on top of a tripod to function as an alt-az head, just like the unmotorized mount on Orion’s StarMax 90 Tabletop, or you can pull the tube off and put it on the mount of your choice.

I haven’t used this mount so I can’t speak for it, but I’ve heard that it’s popular with daytime photographers because it can remember several pre-programmed points and slew to them on command, which helps people make panoramic photos and such. The tube I can speak for, because I used to own the Orion version, and it is a wonderful little machine, solidly built and typically with very good optics. (If you’re wondering why I don’t own that scope anymore, I sold it to buy a vintage orange-tube C90, sold that because the rotating barrel focuser was a pain to use at high magnifications, and since then I’ve been without a small Mak–until now!)

The SkyWatcher package is apparently on closeout. At least here in the States, SkyWatcher has been absorbed by Celestron (both are owned by Synta, who makes the gear) and the SkyWatcher-branded stuff is being phased out (as I predicted a couple of years ago). So this package might not be around for long. Right now it’s $179 plus $20 shipping, so for slightly less than the StarMax 90 Tabletop you get the same tube and a similar tabletop alt-az mount, only motorized and with tracking (not GoTo; the mount won’t find things in the sky for you, but if properly leveled and aligned it will track things once you find them), and 3 eyepieces instead of 2.

There’s one more scope I should mention: the Backpacker 80R has the same tracking mount with a wide-field 80mm refractor instead of a 90mm Mak. It’s a little lighter and a little cheaper at $155 plus $15 shipping. The refractor tube appears to be the same as Orion’s GoScope 80, which has gotten good reviews both on Amazon and at Sky & Telescope. Be aware of the significant design and performance differences between the 80mm refractor, which is specialized for low-power, wide-field views, and the 90mm Mak, which has a narrower field of view but much more capacity for magnification, especially on bright targets like the moon and planets.

Which of these scopes would I choose? Well, I ordered a SkyWatcher 90mm Backpacker earlier today, so there’s your answer. I’ll let you know how it works out. UPDATE: see these subsequent posts for the unboxing, first light, and some additional observations.

What if you read this post after all these deals are gone? Get one of the Orion tabletop scopes–the GoScope 80 (80mm refractor, $110 right now), SkyScanner 100 (100mm reflector, $110 right now), or StarMax 90 TableTop (90mm Mak, $200 right now). They’ve all gotten good reviews, the Mak isn’t that much more expensive than either of the Maks featured above, and the refractor is significantly cheaper (but lacks the tracking mount of the 80R).

One last thing: if you get a C90, don’t just slap it on a cheap photo tripod. It’s too heavy, and at the relatively high magnifications the scope’s long focal length delivers, the shakes will drive you crazy. Trust me, I hated my first Mak until I got a decent mount and tripod for it. You’ll need something like the Orion VersaGo II, Astro-Tech Voyager, Vixen Mini-Porta, or one of the nicer Bogen/Manfrotto units at a minimum, and these can easily set you back as much as the scope did in the first place. If you’ve already got a cheap tripod and two hundred bucks to spend, I’d go with the SkyWatcher unit or the StarMax 90 Tabletop. With their integrated mounts either one might work on top of your existing tripod, which only has to hold the unit up off the ground, and if it didn’t, you could still use it in tabletop mode while you save for a better tripod or whip up a homebrew (like this one).

Thanks to the folks in the Cats & Casses forum at Cloudy Nights for bringing these deals to my attention, and for the astrophoto links used above. The CN thread on these deals is here.

Something new under the stars

Virtual star parties.

Google+ allows multiple video streams at once. The number of amateur astronomers across the continent with video cameras is probably in the low thousands. Get several astronomers steaming live video of celestial objects, a few knowledgeable people answering questions, and a few dozen to a few hundred enthusiasts following along, and you’ve got a virtual star party.

It’s not my idea, and I’m not speaking hypothetically. This is happening, right now (well, maybe not right at this minute, but in the larger present). Fraser Cain, who runs Universe Today, seems to be the nucleating center. There have been several virtual star parties to date, with pro astronomers Phil Platt (Bad Astronomy) and Pamela Gaye (Star Stryder) participating and answering people’s questions. If you’d like to get in on it, join Google+ and add Fraser Cain to one of your circles. You’ll get updates when virtual star parties are coming up. Apparently there  is no set schedule, as this is still a new thing and sort of experimental, but from what I hear the response has been great and there will be more.

I say “from what I hear” because I haven’t been to one of these shindigs. I heard about them from a fellow PVAA member, and I’m just passing the word along. You can tell from my posting rate these past few months how much time I have. (And yes, the irony of me complaining about too little time, given this blog’s subtitle, is not lost on me.)