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

July 16, 2012

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.

UPDATE: the TS70 performs MUCH better after having been disassembled and reassembled (details in this post). It’s not hard, all it takes is a screwdriver. Blackening the lens edges with a Sharpie improves the scope’s already decent contrast, and shaking the lens cell a little while the objective lenses are loose will improve the collimation. After doing only that, I can now take this scope up to at least 133x without the image falling apart. It’s like a whole new scope. That said, there are still better choices out there – see my astronomy wish-list for beginning stargazers for some suggestions.

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.

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30 comments

  1. Hi Matt.

    Great to have you back and posting Big Time! Between your posts and Terry’s, 10MA has become a virtual online classroom for me.

    I, too, have the Orion Expanse 6mm and have found it an exemplary high mag lens made even more useful with the wide AFOV.

    I was intrigued (and somewhat relieved!) by your comments that you detected no really significant difference, re FOV, when moving back and forth between the 66-degree field of the Expanse and the 82+ of some of the ultra wide angles. Kind of surprising. But good to read as I have been debating whether to pony up the money for one of the UWAs. Now I am a bit less inclined to do so. With 32, 25, and 10 Plossls, a 15 SWA from Agena (an outstanding EP), and the Expanse 6 plus Barlow Shorty, I am probably as well stocked as I need to be right now.

    I have tried ordering EPs from Owl several times over the past few months and they are always out of stock one everything. Usually there is no indication of this, so I place the order only to receive an email informing me of the out of stock status and asking me if I want to keep the order in or cancel. Another guy up here has had the same experience. Good gear from everything I read. If you can get it. I will maybe try again today or tomorrow.

    Man, you and Terry had a Messier orgy up there! I experienced an observer’s high just reading your account.

    How long a drive is that for you guys?

    I ended up buying a TS70 (from Amazon via your site link, of course) and haven’t really used it yet, so i was buoyed by your glowing report of its optics. The lack of high mag performance isn’t that big an issue for me as I bought it mainly for wide field viewing, sort of like I currently do with my SkyMaster 15 x 70s but with the option of having the ability to double or triple the mag with the same aperture. We’ll see how well this pans out. I took it out last night but by the time it was dark it had completely clouded over, so no first light run.

    I really don’t know I bought the TS70 other than the above rationale, this and that I thought it just looked kinda cool and I loved the whole backpack observatory thing. So good to hear that it served your well, albeit in a limited capacity, during your Night on Mt Baldy.

    Like you, I use the PSA almost exclusively and find it by far the most easy to use as a navigation tool but, as Terry says, sometimes I wish it had more stars so I could figure out where some particularly interesting star grouping I sketched was located. I do have Will Tirion’s SA2K on what amounts to permanent loan from out library and then the PSA isn’t quite enough, I usually find what I need in there. At this point, fewer stars is most often a plus for me.

    Great blog, superb posts. Keep them coming.

    Doug


  2. I have tried ordering EPs from Owl several times over the past few months and they are always out of stock on everything.

    I hear you. I’m having the same problem getting a filter. But the price is so good I have just resigned myself to waiting.

    Man, you and Terry had a Messier orgy up there! I experienced an observer’s high just reading your account.

    🙂 It’s funny–it took me more than two years to get through all the Messiers the first time, and now I think of knocking off a third of the list in a couple of hours as an entertaining diversion. So why keep doing it? Well, even now it helps build my navigating and observing skills, it’s a fun challenge with a small scope or binoculars, and many of the Messiers are not only beautiful themselves but are set in beautiful starfields. I just love them.

    How long a drive is that for you guys?

    Ha! This may not make you happy. It’s 15 miles from my front door to the observing site. Takes about half an hour since it’s city streets for the first 5 miles and windy mountain roads for the next 10.

    I am coming to the realization that I just haven’t taken enough advantage of being so close to reasonably dark skies. I’ve probably been to the Salton Sea (125 miles from my front door) more often than I’ve been up Baldy. That’s just crazy.

    I ended up buying a TS70 (from Amazon via your site link, of course) and haven’t really used it yet, so i was buoyed by your glowing report of its optics. The lack of high mag performance isn’t that big an issue for me as I bought it mainly for wide field viewing, sort of like I currently do with my SkyMaster 15 x 70s but with the option of having the ability to double or triple the mag with the same aperture.

    Quality control on inexpensive scopes is often quite variable, and it may be that I got an inferior sample and that yours will handle magnification better. Give it a shot and see what you find.

    I really don’t know I bought the TS70 other than the above rationale, this and that I thought it just looked kinda cool and I loved the whole backpack observatory thing. So good to hear that it served your well, albeit in a limited capacity, during your Night on Mt Baldy.

    Oh, I’m plenty happy with mine, and I’m sorry if the report made it sound otherwise. But it is a limited tool, whereas a 6″ Dob is really a good all-purpose scope.

    Great blog, superb posts. Keep them coming.

    Thanks for the kind words–glad you’re finding them useful.


  3. A little industrial velcro and some pvc pipe fittings do wonders for building and mounting finder scopes and it’s easy on and easy off.. Just a thought


  4. Many thanks, once again, for the detail you include in your reports. It’s dang interesting, and I appreciate the pointers to budget options.

    How would you say the Owl Super-Wides compare to the Orion Expanse?


  5. Can’t say for sure, since I only have one Expanse and no Owls. But I haven’t heard anything bad about them. They look identical to the Expanses and come in the same focal lengths. Those things by themselves don’t guarantee the same optical quality, I just bring them up to point out that, as far as I know, they’re the same eyepieces except for the branding.


  6. Regarding your 70mm refractor, you might want to check your scope for miscollimation or pinched optics by doing the star test – slightly defocusing a very bright star at high power. Nevertheless, its a cool-looking scope with the black exterior, as was the Celestron version of the Short Tube 80 (seen in Rod Mollise’s pics).

    The Tri-Atlas is a wonderful resource – I use Set B (shows stars up to 11th mag.) on the field. On occasion though, I’ve had to rely on the higher resolution charts of Set C (stars up to mag. 12.6) to know exactly where to look for the really faint galaxies.


  7. I’m thinking of getting an Apex 102mm and putting it on the SkyWatcher AZ4, but am concerned about the lack of slow motion controls. How do you find it? Is it difficult to make small position changes, especially at high power?


  8. Hi Russel,

    Others may have different experiences, but I’ve found the SkyWatcher AZ4 to be an exceptionally smooth mount. The adjustable tension on both axes really works. I usually tighten in down for storage, so when I set up I spend a few minutes tweaking the tension to get it just right. After that, no problems. I use the AZ4 with my Maks and I routinely run the power up between 200x and 300x with no problems. I’ve had the power up to 500x with the Apex 127 and the mount was still tracking smoothly. I have used other alt-az mounts that had differing degrees of slip going up and down–for example, you get backlash tracking up so it’s always best to aim above the target and gently adjust downward. Not so with the AZ4. Mine just goes where it’s supposed to and then stays put, assuming I got the tension correct.

    I’d be interested to hear from other AZ4 users. With a lot of astro gear there is some variation from unit to unit. I don’t know if my particular AZ4 is good, bad, or average among its siblings. I’m guessing pretty darned good, but maybe they’re all this good. So if you’ve got one, don’t keep quiet!


  9. Thanks! That is very helpful.


  10. I have the Orion version which is exactly identical to the Skywatcher AZ4, called the VersaGo II. The altitude and azimuth movements on it are not smooth, but herky-jerky. Greasing up the mount head might help. The panning handle is long and can get in the way when viewing through a star diagonal, so I attach it on the back of the mount head when using a refractor or Cas-Mak on this mount.

    The Vixen Mini-Porta mount (with slow motion controls) might be stable enough for the Apex 102mm. It retails for the same price as the AZ4/VersaGoII and weighs only 6 lbs. Maximum load capacity is about 6.6 lbs.


  11. Yes, I’ve been looking pretty seriously at the mini-porta as well.


  12. […] […]


  13. travel scope 70 es un monstruo con oculares de focal 32 a 25.gran campo de vision,muy luminoso y contrastado con el de 25.ami skymaster 15×70 le gana por mucho en claridad y nitided.necesita cielos oscuros,en canbio en planetaria es muy justito.En verano e recorrido sagitario andromeda y el doble cluster de perseo es una maravilla.he visto m81 y 82,claro sin detalles y mas objetos mesier.El secreto esta en buscar una pupila de salida mayor de 4mm para espacio profundo.Con una diagonal de 90 grados de mi astromaster.


  14. […] time I used my new tandem rig: my Apex 127 Mak with my SV50 refractor mounted alongside as a deluxe finder. This idea, of having a small […]


  15. Hi Matt,

    Just re-read this post as last night, finally, we had some patches of clear sky that gradually became larger. But with a near full moon hovering in the east, I didn’t want to set up anything elaborate, so I just took out my little Travel Scope 70 which I’ve not used since early last fall.

    Yes, the skies (never actually, you know, DARK) from my patio were predictably washed out, but at least a darker charcoal gray, and an east wind had kicked out some of the pollution so the seeing was . . . not bad at all.

    I had forgotten just how crisp the optics are in this modest little scope. I got smashing views of The Hyades and, especially, the Pleiades, maybe the best look at M45 I have ever had in terms of both getting the whole thing in coupled with astonishing brightness and contrasty clarity, and I picked up a good 40 stars (at 20x) including that delicate little string that extends down from the handle area. I drank this in for a good 15 minutes. Has to be the most gorgeous star grouping up there.

    Then I found M46 and M47, neither with a large number of stars, but what I could see were jewel-like. What really was delightful was that whole area north of Sirius that includes IC 2177, Gum 1, four NGCs and M50 (the latter barely visible but still very much there). Also found Cr 121 to the south and spent some time stargazing in and around the Aludra-Adhara area. I was only out just over an hour as the clouds eventually moved in, but a good night, and one that renewed my earlier positive impressions of this $50 wonder.

    I just discovered a (often) green-blue site only 20 minutes from my house (the Tualatin River National Wildlife Refuge) and will probably take this scope and my 15 x 70s there for my first test run. All I need now is a clear night.

    Based on last night, I am looking at the 120mm/f5 OTA refractor on the Orion Web site as a possible Drive-To scope. I’d like to hear your thoughts on this baby, a true one-hander, put it on a tripod and be observing in under a minute but with vastly superior light-gathering and optics to the TS 70. Great user reviews and it does have a 2″ focuser. Terry, you and David can jump in here, too.

    The weather is finally warming up here, and some clear nights are not far away.

    Best,

    Doug


  16. I’m glad that you managed to get a good sample of the Celestron short-tube 70. A while back, I picked up a longer focal length 70mm Celestron Powerseeker AZ, but the scope was really off collimation, giving poor views. I just recently tweaked it the best that I could and will test it once the skies clear up here in SoCal.

    I heard that the 120mm f/5 makes a good DSO scope, but not good for solar system objects (and really bright stars)!


  17. Hi Terry.

    I erred. The Orion is actually a 120, NOT a 102, so a pretty big refractor and weight may be an issue. The price for this 120/f5 is $329.99 and you need to add mounting rings and a dovetail mount, and diagonal so the total would be closing in on $400-450. I already have a finder I can use.

    However, I came across what looks like an amazing 102, this by Explore Scientific, for $449 and that covers everything, including an 8 x 50 finder AND a Crayford-style 2-speed 10:1 2″ focuser AND 99% diagonal (the Orion 120 does not include any diagonal) along with a carry handle built into the rings, a la the Orion XT 4.5. I read some reviews on the forums, all of which say Great Scope, even greater dollar value.

    Here is the link. I’d really like to hear your thoughts.

    Doug

    http://www.telescope.com/Telescopes/Refractor-Telescopes/Refractor-Optical-Tube-Assemblies/Orion-120mm-f50-Refractor-Telescope-Optical-Tube-Assembly/pc/1/c/10/sc/346/p/9836.uts


  18. Ooops. Sent the wrong link, Here is the one for the Explore Scientific AR 102.


  19. I am an idiot. I sent the message without the link, Finally, at last, here it is:

    http://www.adorama.com/ESAR102.html


  20. Wow, looks awesome, especially with all the accessories that come with it! Really nice compromise between a short F/5 and long F9.8 focal length scope that me and David own.


  21. My thoughts exactly, Terry, especiaily the halfway f/lk. Amazing scope, even more amazing deal. I am going to order one tomorrow and will try to sell my ETX-80 and Sky0Watcher Mak 90, the latter having the motorized mount for tracking should be the easier sell.


  22. Great! Sorry that your ETX-80 didn’t work out well. I’ll need to start learning how to unload scopes in the future…


  23. Damn. Adorama is closed until next Sunday for Passover, and they are out of stock. With a deal like this, hardly surprising, I may just go ahead and place the order and wait a reasonable time.

    As for selling scopes, craigslist is by far the better option (vs ebay). It’s free, you get 4 photos in your listing, and in a population base the size of L.A. you should be able to sell anything in a week. ebay has some fees, not all that much so no big deal, but boxing up a scope any larger than the SkyScanner plus the high costs of shipping something that big and heavy can be prohibitive. Craigslist is the way to do it.


  24. Thanks for the info, Doug!


  25. […] 50mm spotting scope, and 7×35 binoculars, and he used them all. He was also curious about the Travel Scope 70 so I tossed it in the car on a whim–this proved to be a fateful decision. As for myself, my […]


  26. […] feelings at the time–explained here–were that the scope was great a low-power scanning but useless at anything over 50x. Terry […]


  27. […] got this scope because it filled a hole in my lineup. My Maks have sharp optics but can’t do wide fields. The TravelScope 70 can do wide fields but still has limitations, […]


  28. […] my most-used atlas, not my only one.). For a dissenting view and an alternative recommendation, see this post and its comment thread for a discussion of Eric Karkoschka’s Observer’s Sky Atlas […]


  29. […] brought the Apex 127/SV50 combo – I’m sighting on the moon here, to align the finder with the scope – and the […]


  30. […] decided to finish with M57, which was fitting since it was a chance observation of that nebula with the TravelScope 70 a few years ago that got me hooked on refractors. I wanted to recreate the […]



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