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Small telescope quest complete

August 10, 2010

When I caught the astronomy bug in the fall of 2007, my first priority was to get a decent scope. I spent about a month doing research in print and online and just about everyone said the same thing: get a cheap 6″-8″ Dob and some serviceable binoculars and start learning the sky.

This I did. My first scope was an Orion XT6 that I named “Shaft”. For two and a half years, Shaft was my workhorse scope.

But Shaft was still getting broken in when I decided that I needed something more portable. An XT6 is about 4 feet tall and weighs 33 lbs. It’s easy enough to  take the tube off the base and stow them both in the car for camping or a trip to the mountains, but I wanted a scope small enough to fly with. My parents live in rural Oklahoma under very dark skies and I knew all too well what I was missing here in the light-polluted swamp of California.

So began my quest for a grab-n-go scope. Not just any grab-n-go scope–some people consider a 6″ Dob to be grab-n-go. What I was really looking for was my “no excuses telescope”: a scope that would be so triflingly small and light, and yet so capable and easy to use, that I would never have an excuse not to have it along, whether I was driving up the mountain for a quick peek or flying to another hemisphere.

I’ve always had a thing for Maksutov-Cassegrains so my first venture was a little Mak, an Orion Starmax 102, that I picked up used. And it was a great scope. But I realized that a StarMax 90 would deliver most of the performance of the 102 but it would be a couple of inches shorter and a couple of pounds lighter (3.5 vs 5.5, if I remember correctly). So I got a Starmax 90, found it delightful, and sold the 102 (that’s my ad photo above).

The Starmax 90 was my small scope for a long time; it’s the scope I waxed lyrical about in this post. But I also thought that the old orange-tube Celestron Cassegrains looked pretty sweet, and I was entranced by the tank-like build and simple operation of the C90. Same aperture as the Starmax 90, but it was another couple of inches shorter. So I found a used one on Cloudy Nights and sold the Starmax 90.

The C90 has been a very fun little scope. It is even more rugged and versatile than I expected, and it fits in an insulated plastic-lined six-pack cooler, to boot. Nothing like getting an armored scope case for $5.99 at Wal-Mart (the black thing laying over the tube in the photo above is the finder, wrapped in one of the soft cloth bags that come over my wife’s favorite shoes).

But on some level I’ve known for a long time that the C90 would be at best a temporary stop on my quest for the smallest reasonably capable telescope. Because a couple  of years ago when I was surfing Cloudy Nights I discovered the Stellarvue SV50.

As I understand it, the SV50 started life as a high-end finder for larger telescopes, and one version is still sold that way today. I fully support that; one of my first upgrades for Shaft was a 9×50 finder that made star-hopping a lot easier. But people started using the SV50 as a telescope in its own right and it developed quite a following. It is now sold as “The Little Rascal”, a stand-alone spotting scope with a clamshell mounting ring, eyepiece, and in the latest guise, a carrying case.

My SV50 was a present to myself for finishing my summer teaching. I bought it from Oceanside Photo & Telescope on the last possible day that I could have done so and still have had the telescope delivered before I left for Uruguay. I was on the phone for maybe 5 minutes tops and in that time the sales guy (whose name I’ve unfortunately forgotten) answered all of my questions instantly and authoritatively, processed my order with admirable efficiency, and even managed to find me a discount I hadn’t known about. If that’s not good customer service, I don’t know what is.

This is a tiny, tiny scope. The aperture is 50mm, the focal length is 205mm, the magnification with the included 23mm eyepiece is 9x. So you could think of it as one half of a pair of 9×50 binoculars. Except that it’s not.

For one thing, it accepts any eyepiece in the standard 1.25″ barrel size, so you can vary the magnification. And it is really, really well made, as one would expect from StellarVue. There are binoculars out there that are made to equal or better specifications, and there are binos that have interchangeable eyepieces, but they’re out of my price range so they don’t come in to this story. And you can put it on a tripod and look at things directly overhead without breaking your neck.

Also, having had the opportunity to compare the performance of the SV50 with that of my admittedly low-end 50mm binoculars, the image in the SV50 seems brighter.  Possibly because it has fewer internal reflections to steal light from the path, possibly because it’s just a better made instrument, possibly because my binoculars are cheap. Whatever. I’m deliriously happy with the SV50.

The SV50 is 9.5″ long and weighs 1.5 lbs. By comparison, the C90 weighs 3.9 lbs fully loaded (i.e., with diagonal, eyepiece, and finder), and the Starmax 90 weighed 4.6 (the less said about the positively Brobdingnagian Starmax 102, the better). Crucially, this means the scope is light enough to ride comfortably on my little Manfrotto 785 tripod, which only weighs a couple of pounds itself.

And that’s good because the folded tripod is the same length as the scope, so it fits into a roughly equal space. I found a little travel shaving kit at Target that holds the scope, doubly wrapped in bubble wrap; the tripod; three eyepieces; the handle for the alt-az head that goes atop the tripod; my mini red flashlight (a mini Maglite painted over with red nail polish); and a small notebook and pen for recording observations. The only thing that doesn’t fit in the bag is the alt-az head itself, a DwarfStar from Universal Astronomics. Close enough, says me.

By comparison, the ~4 lb C90 and StarMax 90 require the beefier Manfrotto 190CXPRO4, which weighs 3 pounds and folds down to 21″. Which, okay, means you can still get away with scope, accessories, DwarfStar, and tripod for just under 9 lbs. But why settle for 9 when you can have 4.5? More importantly, I have not had the courage to put the bigger (and much more expensive) tripod in my carry-on luggage. For the love of Pete, I use a netbook as my primary computer because I hate carrying heavy stuff through airports. Anything that gives me adequate functionality at half the volume and mass, I will be on in a heartbeat.

For eyepieces I’ve been using the included 23mm eyepiece, yielding 9x; a 10mm Orion Plossl giving 20.5x; and a 6mm Orion Expanse giving 34x. At 9x the SV50 functions as its own finder and requires no other. At 20.5x the scope just gets out of the way and lets me observe. It is honestly one of the most hassle-free setups I’ve ever used. At 34x the optical train is starting to pant a bit. A focal ratio of f/4.1 is hard on eyepieces, especially widefields. The view is still acceptable but focus gets to be very touchy. Fortunately the built-in helical focuser is super-smooth, with no backlash, and is a real joy to use. At the end of the day the three eyepieces get rolled up in a Ziploc bag to fit into the small empty space between the scope and tripod.


So far my SV50 has only seen serious use away from home. In Uruguay I used it to do all of the observations for the Southern Sky Telescopic Club, and this weekend in Big Bear Lake I spent a pleasant hour chasing some Messiers. In fact, I’ve decided to re-observe all of the Messier objects with this scope. I don’t know how long it will take because it will absolutely require dark skies, which I don’t get to as often as I’d like, but I’ll just chip away at it as opportunities present themselves. In any case, I think my quest for the “no excuses telescope” has finally come to a happy end.

I don’t know what I’ll obsess about next, but if you stick around you’ll probably find out. Clear skies!

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18 comments

  1. I enjoyed this post because I have been shopping online for about a year now, trying to decide what is more important to me in a telescope: aperture or portability. Seemingly easy question to decide on, but one that has me see-sawing back and forth between Dobs and catadioptric telescopes.

    Portability for me is key, but I would hate to have a smaller scope if it resulted in a big reduction in the scope’s versatility. I’d like the scope to last a little while before I upgrade.

    So my question to you is, what can you see well at 20.5x and 34x with this little scope AND what celestial sights does this scope leave to be desired?

    FYI, I do binocular astronomy right now, so I have experience with 10x magnification and virtually no other magnifications higher than that. I’m not in an area where I have access to star parties or “loaner scopes” (Peace Corps Volunteer in a rural town in Morocco).

    Nice site by the way, I enjoy reading it!


  2. […] quest complete Telescope tradeoff: aperture vs portability August 14, 2010 In a comment on the last post, Jon Lindberg brought up some good points about the aperture/portability tradeoff […]


  3. Hi Jon, thanks for the kind words. I kinda-sorta tackled these questions in the next post, but in case I didn’t sufficiently answer your question: the SV50 excels at sweeping the Milky Way and does a surprisingly respectable job on the brighter clusters, nebulae, and galaxies. That said, a lot of DSOs don’t look like much in it, just little patches of fuzz. I think of the SV50 as a sort of sturdily-mounted superbinocular, in that my observing with it tends to the same sort of best-and-brightest targets, and just cruising around the sky. I haven’t used it much on planets, and I’m not expecting much. Jupiter and Saturn are recognizable but that’s about it. For the moon and planets, the C90 is another league and a 5″-6″ scope is in another league beyond that.

    Since you already have binoculars, I think something this small would duplicate a lot of your existing capability without adding much. On the CAT vs Dob question, I’d go for a CAT in 3″-4″ range and a Dob at larger sizes, mainly because I don’t dig on figuring out how to mount big telescopes. Dobs come mounted so the work is already done for me. But there is no question that big CATs are a lot more portable than big Dobs (in apertures under 12″, anyway), even with the mount taken into consideration.

    That’s about all I can say without knowing more about your constraints and desires (i.e., does the scope have to fit into the trunk of your car or the overhead compartment on an airplane, what is the most weight you’re willing to handle, do you do more planetary observing, more deep sky, or both about equally, etc.). Feel free to write back, and good luck with your quest!


  4. […] catch at least one through binoculars. Brian had along his 10x50s and I had my 10x50s, 15x70s, and SV50. We looked at just about every good target with all three instruments. Usually we’d find […]


  5. […] a 10″ dob is as much big iron as I need for at least the near future. I found my ultimate no-excuses travel telescope. And I got a couple of nice mid-sized telescopes, both of which turn in good images without […]


  6. […] So I’ve been on a quest not only to find the perfect small scope for myself (a quest that is complete…for now), but also the perfect small scope to recommend to other […]


  7. […] a closeup of Venus and the moon, shot through my SV-50 and a 32mm Plossl (7x), […]


  8. […] 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 […]


  9. […] 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 rich-field scope mounted […]


  10. […] 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 […]


  11. I’m a college astronomy major who’s been shopping for a telescope for my studies for about a month now and I have a pretty good idea of whats out there, but I’m not sure exactly what scope is going to best meet my needs. I’ve yet to see anyone with as much hands on experience with small telescopes as you, and I’m hoping you can advise me on the matter so that I can finally get rid of this headache and settle on something to buy. My situation is that I live in the inner city of a moderately light polluted metropolis (Saint Paul, MN) and my best observing site is a semi-dark (still lined by street lights) public park about 3 blocks away. Since I don’t have a car I’m looking for a scope that I can comfortably carry, preferably in a backpack, the 3 blocks to the nearby park then set up and take down quickly. 20lbs or less would be ideal for the weight of the telescope & tripod together but I can go a little heavier if needed. The things I would like to be able to observe wiht my telescope are Mars, Saturn, Jupiter, and all 110 of the Messier objects. My budget is somewhat limited being a college student, I’m looking at being able to spend up to $650 or so for the telescope, tripod, and any accessories like additional eye peices or a upgraded finder.

    So, given your extensive experience with small telescopes, what backpack-able telescope and tripod / accessory combo would you recommend to give me the best views of the planets and Messier Catalogue? I’ve been thinking about the Orion SkyQuest XT4.5 with the addition of a 2x barlow and a 9×50 RACI finder but 17 lbs is still a lot to lug 3 blocks each way when you have to carry it by hand (beccause theres no way that thing is fitting in a backpack), and after reading your blog I can’t help but wonder if maybe there was something smaller and more portable that might still be able to cut through the moderate light pollution of the inner city and show me all the Messier objects and planets. Any suggestions?


  12. It depends on how dark your semi-dark site is at the park. I define semi-dark as a suburban sky, which is coded orange on the Bortle scale (may want to look this up online if not familiar with this scale). If you are just able to see the Milky Way band across the sky (cutting through Cygnus and Lyra) with your eyes, then I would consider the sky semi-dark.

    In any case, I would recommend the Astronomy Without Borders 5.1″ F/5 collapsible tabletop dobsonian:

    http://shop.astronomerswithoutborders.org/products/astronomers-without-borders-telescope

    5.1 inches (130mm) with 650mm focal length (F/5) is plenty of aperture to see all the Messiers in a semi-dark/suburban sky (and plenty of non-Messier deep sky objects as well). This is a good planetary/deep-sky instrument.

    Only problem is that it’s a tabletop, you’ll need to find something like a picnic bench to set it on. Also it’s an open tube design, so if you have stray light coming at you from your location, may need to create a shroud for it.

    But the collapsed tube easily fits in any standard school backpack, and you can easily carry the tabletop by hand (there’s a handle on the mount). Hope this helps.


  13. Hi Matthew,

    Sorry to take so long getting back to you, I have been absolutely slammed with teaching lately and it’s not over yet.

    Terry is the real small-scope-meister and his advice is already very solid.

    First thing is, with small scopes, aperture definitely wins, especially in town. It comes down to being able to increase image scale AND maintain image brightness, relative to smaller scopes.

    On your budget, and given the distance you want to walk, that nicely narrows down the possibilities. You can immediately abandon refractors–a cheap, backpackable 5″ reflector can be had for well under your budget (leaving some money for a stand and accessories), but a cheap, backpackable 5″ refractor barely exists. The Orion 120ST, I suppose, although it might be pushing the boundaries of “backpackable”, especially with a sturdy mount.

    I think Terry nailed it with that 5″ collapsible Dob. You could put the scope in a backpack and a collapsible table and folding chair in your hands and be set. Or maybe two folding chairs, and just set the scope on one of them.

    I can think of one other possibility worthy of serious consideration: a 6″ SCT on something like a Vixen Porta mount or Orion VersaGo. I have walked blocks and blocks with my Orion VersaGo II over my shoulder and it was no hardship. And the Celestron C6 OTA is pretty well-regarded, from everything I can find out. I have seriously considered one myself, and only went for a 5″ Mak because I wanted at least one reasonably capable scope that I would not have to collimate. On your budget, you might have to find a used C6, but they turn up on Cloudy Nights and elsewhere with fair regularity. Flipping back through the older ads will give you an idea of a fair street price. And OPT puts that OTA on sale from time to time.

    Good luck with your quest–please report back sometime and let us know how things are working out!


  14. Hi Matthew,

    One more possibility is the Viixen R130sf 5″ Newtonian that OPT now has packaged with the VIxen Porta II mount for $399 w/free shipping.

    http://optcorp.reachlocal.net/vx-39954-r130sf-130mm-newtonian-reflector-w-porta-ii-mount.html

    I bought this about 2 months ago and it’s an exemplary package. Razor sharp optics, good light gathering, lightweight, smooth focuser, and the Porta II provides a rock solid base with smooth and precise slo-mo controls, a real asset. I don’t see a much better bang for the buck.

    I also bought on ebay a well-padded carry case for the OTA that is a near perfect fit and has a pair of large zippered side pockets to hold your finder and accessories along with a wide mouth dual-zip top opening for easy in-and-out. If you want to the link, I can find it for you. Cost is $34 w/free shipping.

    The case has both wide shoulder strap and dual handles, so you could carry it on one shoulder, the Porta II on the other, as Matt does, and have a free hand for a small, collapsible chair. Three blocks should be a snap. And you’d no longer require a table or park bench.

    Best of success in your quest.

    Doug


  15. […] a very convenient carry handle opposite the dovetail bar. With the rings in place I could mount my StellarVue SV50 as a finder, and I was ready to […]


  16. Excellent Work! Keep it up!


  17. […] of enjoyment out of smaller telescopes, and some of us have a possibly unhealthy fascination with tiny telescopes. But if you’re just starting out, you need some early wins, and a 4- to 8-inch scope will […]


  18. […] about small scopes, and after getting the little SV50 refractor nearly six years ago, I declared my small telescope quest complete. But the SV50 turns out to be a more satisfying finder than stand-alone scope, even for air travel. […]



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