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Starbuckets – an UltraLight Experience Tom Trusock – 8/2004

Reviewed: Starbuckets 8” f5 Truss

Features: Ultralight 6 Pole Truss Design 2” Moonlight Focuser (Dual) Royce Primary Antares Secondary Astrosystems Secondary Holder & Spider Rigel QuickFinder Light Shield and Shroud No-tools assembly Eighty millimeters.

That's how big my last travel scope was.

Eight zero mm

Oh sure – it was a great scope - took high and low powers with aplomb, had minimal chromatic aberration, a decent focuser, but….

It was still only 80mm

Camping trips off to the big deep dark up here in Michigan really deserve more, but frankly - with a wife, one kid, and another on the way - there just isn't *that* much room in the SUV anymore. Well, assuming I Starbucket Hots Starbucket Nots want to go along for the ride anyway. A 6-8 inch scope would • Amazingly lightweight and • Stability at 300x + be nice, but how? A Mak, SCT portable • 8” is not airline portable or refractor would require me to • Excellent Service and Support • No furnished case or truss tote along a mount, and a solid • Superb fit, finish and mechanics pole bag tube dob would simply take up • Wonderful, superb, fantastic • Non-captive hardware too much space. To keep optics everything to a minimum • Supplies extra “easily lost (especially the mount) it would components” have to be a truss dob of some • No tools assembly (Allen sort. To this end, I'd been wrench required for collimation) thumbing my way through the • A lot of aperture in a small myriad of ATM sites on the space

internet and even contemplated building my own. At this point my friends staged an intervention to remind me my lack of carpentry skills is legendary. Finally, I was referred to Starbuckets – a small company owned and operated by Neil Carroll. Here at last, was a scope that showed some real promise.

But first - some background.

Fellow dobbers know that it was a monk named John Dobson who showed us the way: How to take nearly any ordinary everyday junk and inexpensively make a telescope - a BIG telescope - out of it.

The Dobsonian revolution has been through two iterations so far – the first was with Dobsons initial creations (somewhat similar to many of the closed tube designs on the market today) - the second came with the publication of Ivar Hamberg’s “[An] Extremely Portable 17.5 inch Dobsonian” in Telescope Making #17 (Autumn 1982). Hamberg was one of the first to construct a scope that fit in the back of a car and could be setup by one person at a remote observing site. You can see the basic design today whenever you look at any truss dobsonian - Obsession, StarSplitter or homemade.

We’re now on the cusp of the third revolution - the ultralight.

Although no one person solely inspired this next leap, innovators such as Mel Bartels, Bruce Sayre, and Albert Highe (among others) built upon the designs of those who preceded them. In particular Highe’s 12” f5.3 ultralight dobsonian took many of the ideas for an ultralight throughout the ATM world and incorporated them in to what’s starting to become a recognizable design. Highe scopes are distinct because of their single ring upper truss assembly, the light shield instead of a shroud, the use of fewer truss poles, their low profile mirror boxes – and most importantly – their small size and weight.

Good Things Come in Small Packages

There are a few commercial manufacturers that currently offer ultralight designs. Neil Carroll – StarBuckets - offers smaller scopes (6”, 8”, 10” and 12.5”). Neil markets his 6” as an airline carry-on scope, and it makes a good competitor – although a bit smaller - to the UTI (another entry in the ultralight dob category, but based on a slightly different design philosophy).

Intrigued by Neil’s products, I gave him a call early this year (2004), and after some discussion placed an order for an 8” F5. I took delivery about 80 days later. My Starbucket came standard with a 8” f5 Royce Primary, Antares Secondary, Astrosystems Secondary support, Rigel Quickfinder, Secondary Baffle, and shroud. I also upgraded the focuser to the Dual Rate Moonlite Crayford (in Blue). I should also add that the fan you see on the back of the scope is my own add on (Courtesy DBA Astronomy), and not Neil’s work. Neil’s integrated fans tend to look a little more – well - *integrated*.

From the very first look, I was immediately smitten – as is everyone else who has seen the scope. At star parties, it draws far more attention than its small size should warrant. The scope is a thing of beauty, and Neil is a craftsman whose attention to detail is obvious from the first glimpse.

Assembled, the scope weighs around 25 lbs, and the UTA is easily carried in one hand. It breaks down into rocker and mirror box, a small bag containing the truss poles/ hardware and the UTA. For storage and protection of the UTA, I elected to go with a Dosko Sport Extra Large case. As you can see above, this case offers enough room for me to store my UTA, several eyepieces, shroud, filters, light shield, and on the bottom level of foam, collimation

Assembly is straightforward, quick and easy – taking about 10 minutes including collimation. Considering you disassemble it every time you pack it up, the scope holds collimation surprisingly well. My only initial concern had to do with the mirror cell. Instead of clips or a sling, Neil uses a time honored method for small scopes - three dollops of RTV. Stemming from an early bad experience, I’ve never been happy with that design. But I’d never seen it done right, either - at least Need a chair with that? before this. Ultimately, my

fears proved groundless. In fact, the more I think about it, the more advantages I’ve found with this method. For one, I never have to worry about the mirror bouncing around in the cell on dirt roads – that’s a rather large piece of mind right there. And with it being spring loaded, collimation is easy as pie.

Most nights, the shroud isn’t necessary and the shield is all that’s needed to block ambient light. However given the low Starbuckets also offers an adjustable height Observing Chair with 8 profile mirror box, I’ve found adjustments at 2.5” intervals that yield seat heights from 13” to 29”, the shroud does make a much and served all my needs both with the 8” and my personal TV102 needed dew shield on damp mounted on a Gibralter. Offered in Red Oak or Hickory, it’s evenings. extremely strong for it’s size and was easily able to support all 265(+) lbs of me without flinching, groaning or snapping. My only Fit and finish is quite nice, and complaints: 1) for us big folks viewing targets low to the horizon it Neil’s attention to detail is doesn’t “quite” go low enough, and 2) the chair was prone to closing obvious throughout. Small as you moved it around. Neil’s response to the second complaint was touches like the use of a star to develop a lock mechanism (not shown) – which he immediately for the handle of the mirror shipped off to me, and incorporated into his current line. Overall, at cover, and using a different $135, it’s reasonably priced and highly recommended for a look for the baseboard legs, comfortable observing experience. fill the niches and combine to make a scope that looks as good as it works.

I’ve had two issues after several months of use. The black coating on the metal is starting to chip in some places, and I’ve had to re-stitch the Velcro on the light shield. Both very minor issues.

It would be nice if the hardware was captive. However - Neil’s apparently aware that little bits of hardware - like the truss poll knobs - can be all to easily lost, and supplies several replacement items for you to keep on hand.

Optics The views are wonderful and (to use a cliché) quite refractor-like, showing pinpoint stars and crisp clean images. I had one of the best views I’ve ever had of M57 through this scope at about 75x (and I’ve looked at M57 through a lot of scopes). From a very dark site, I found it to be nearly an emerald green elongated donut that floated in a sea of pinpoint stars. It took my breath away, and I sat and stared for a very long time. The 8” f5 mirror provides a true field of around 2.3 degrees with a 35 panoptic (although as you can imagine, there are some balance issues with extremely heavy eyepieces), yet is long enough that coma is not overly intrusive. If the focal ratio were much faster than this, I’d probably want to use a paracorr.

With a well cooled and collimated mirror, on-axis lunar and planetary views are superb, extremely sharp and contrasty, again – quite refractor-like. The smooth surface of the mirror lends itself to high contrast views of the moon where the most subtle shadings are evident. The only real optical drawback was the presence of secondary spikes on bright planets that are common to most Newtonian telescopes (Starbuckets uses a standard 4 vane design). One of these days, I’m going to get around to trying a curved secondary.

Optically, this scope amazes me every single time I take it out. If this sample is any indication, R.F. Royce is without a doubt one of the master opticians in the business today. I’d have absolutely no hesitation about going with another one of his products in future scopes, and would go so far as to put him on my list of mirror makers to actively seek out. The Starbucket structures do these fine optics justice.

Overall, motions are quite smooth and buttery, and the scope balances fairly well with 1.25 eyepieces. Counterweights are part and parcel with dobs. Each dob is a little different, so I really can't say what another would have to do, especially on a scope this lightweight. This one works fine with most all the 1.25" eyepieces I've used except for the 24 pano - with that one I put another eyepiece on the back end. It's a convenient location to stick an eyepiece actually.

I found the scope to be fairly stable up to around 300x (an excellent magnification for a small scope in the Midwest), with dampening times of only a few seconds.

At f5, the dual speed focuser is highly recommended, and does a very nice job. While the Moonlight isn’t quite as nice as a FeatherTouch, it has the advantage of being much lighter – an important point given Starbuckets design philosophy.

Drawbacks?

I was mildly surprised when the Hardin 12” (w/fan) I demoed earlier this year cooled down before the 8”, but in retrospect, given Neil’s closed (abet well ventilated) mirror box design, I suppose I should have expected that. I wound up adding a fan to the rear of the telescope, and it speeds cool down time greatly. As with any Newtonian telescope, I’d urge you to add a fan – unless you are a very patient person. Talking with Neil on this point, I encouraged him to add a fan as a standard feature on the 8”. While his web page currently does not list it, he thought it was a good idea, and stated he would. Check with him when ordering.

I found the short distance from the secondary to the edge of the UTA to be problematic on early spring evenings as I picked up dew several times, and even frost on occasion. Although I’ve purchased the smallest Astrosystems dew guard, the secondary is too small for it to be installed with out modification.

The lightweight design does not have the mass to absorb shakes and shimmies like larger heavier dobs, but this is a trade off I’m willing to make for extreme portability. Being an 8” f5, the eyepiece height is fairly low, but the easy (yet not quite complete) solution was to purchase one of Starbuckets observing chairs (see box out). It works wonderfully, and it sees use with all my scopes. It’s reasonably priced and highly recommended.

Finally, you should also be aware that you will need to find a source for a UTA case and truss pole bag as neither are offered.

Comparisons and some conventional wisdom debunked…

I’ve been asked over and over again how this 8” f5 (~$2100) stacks up to my 4” f8.6 Apo (~$2600). Well – it’s not a pretty story – from the apo lovers standpoint.

Aperture rules.

It’s a cliché, but it’s also a fact. Comparing 8” of quality aperture to 4” of quality aperture isn’t even fair. Consider the following: With my Pan 35, the TV102 yields a 2 degree, 43 minute true field of view. With

7 Copyright © 2004 CloudyNights Telescope Reviews the same eyepiece, the Starbucket yields a 2 degree 21 minute true field of view. Dawes limit for the 4” is 1.14 arc seconds, compared to .57 arc seconds for the 8” scope. Light gathering? Consider: 12.56 sq inches for the 4” scope vs 50.24 sq inches for the 8” scope. The 8” scope has 4x the light gathering capability of the 4” scope. That works out to a full 2.5 magnitudes. Obviously, they aren’t even in the same class on deep sky objects.

“Ok, I’ll yield the DSO’s,” you say, “but surely the apo will do better on the moon and planets due to it’s lack of central obstruction and correspondingly higher contrast.”

Ummm – nope. 8” vs 4” is just too much of a difference. Often there’s enough new detail on the lunar tableau to make me think I’m looking at a totally different moon. Planets, I’m sorry, but it’s the same story. 8” of cooled down and well collimated Royce mirror just visually beats the pants off my 4” apo Don’t get me wrong, the 4” APO is an exceptional scope in it’s own right, but 8” vs 4”? Sorry – there are laws of physics here...

“But f5 is too fast for a planetary scope…”

Ok, there’s a point here – kinda sorta mebbe. The one drawback with this scope is that due to the fact that the mirror is an f5, you need to keep the object d’interest fairly well centered. Image degrading coma does begin to show up off axis. Just how much you’ve got to play with depends on the magnification you are using and your personal tolerances – but it can still be an extremely effective planetary scope.

“But the apo is far more portable…”

Nope. One thing many folks forget to consider is the mount. When you consider the mount you have to pack along with a 4” apo, the StarBucket takes up about ½ the room.

“But diffraction spikes! Diffraction spikes!”

Visually, some dislike diffraction rings you get with a 4 vane spider, but personally I’ve never had much of an issue with them.

“Ok Mr. Smarty Pants Reviewer – is there anywhere in your opinion a 4” APO beats the 8” StarBucket?”

Well, actually – yes. And I’d like to make it clear that I, for one, hope to never be without an APO.

• One advantage of the refractor is cool down time. While this was plainly evident in the spring, it was much less so in the summer. In fact, I attempted several times this summer to obtain temperature charts, but due to the distinct lack of a temperature differential was unable to do so. ANYWAY – while apo’s do require some cool down time, it’s not usually much – dobs on the other hand, do.

• Fuss factor is another. It takes about 15 minutes to setup and collimate the StarBucket, and while this isn’t very much time, it only takes about 2 minutes to slap an APO on an alt/az mount and be good to go.

• Comfort may be a third area. An 8” f5 is a SHORT scope. Often I had my posterior on the concrete, or propped just a couple of inches off. The Starbucket Observing Chair, while an excellent piece of work, sometimes isn’t quite low enough. When in the field, I tend to keep an eye out for short rock walls. I’m also thinking of bringing along a milk crate – great place to store charts and misc items as well. With the 4” apo, I’m able to keep comfortably seated.

• Finally, it would be easier and cheaper to get a driven mount for the APO than to pop for a Dob Driver or Servocat for the Starbucket.

But, if you are looking for the most aperture in the smallest package you can get – then the Starbucket wins – because that’s what it’s designed to do.

Final Words… One of the nice things about ordering a custom scope like this is the folks you get to “meet”. I found Neil accommodating, helpful and very personable. Excellent to work with, he delivered his product in a reasonable amount of time, and I’ve enjoyed my exchanges with him – before, during and after purchase.

Starbuckets 8” f5 is a wonderful travel scope for someone who does not need an airline carry-on capable package. It packs into about ½ the space of my already portable TV102, and yet its light grasp is nearly 650% of my old 80mm travel scope (50.24 inches vs 7.79 inches of area). It can be set up in a moments notice, and provides absolutely wonderful views of lunar, planetary and deep space objects. It’s an amazing scope.

Neil Carroll and StarBuckets are to be commended for being one of the first vendors / manufacturers to bring the next dobsonian revolution to the consumer.

If you’re in the market for an extremely portable premium dobsonian, Starbuckets comes highly recommended. Heck - I’d buy one. Oh wait… I already did. Now if I can just get it away from my daughter…