Joe Bergeron's Astronomy Equipment Reviews

Televue Pronto
Questar 3.5"
Starsplitter 10" Compact
Coronado PST

Denkmeier II Binoviewer
Losmandy G-11 Mount
Desert Sky Astro DSV-1 Mount
Telrad
Rigel Quikfinder
Televue Quickpoint
Televue Starbeam
Astro-Physics Maxbright Diagonal
Televue Radian Eyepieces
Televue Nagler Type 6 Eyepieces
Stellarvue F50 Finder
VERNONscope Brandon 94mm Refractor
78mm f/6.5 Jaegers Refractor
14.5" Sky Designs Dobsonian


The TeleVue Pronto, now discontinued, was a sweet, beautiful little telescope. I owned and sold two of them. They suited me well, being very solid and well-made. The lenses gave some of the finest star images I've ever seen. However, it should be noted that by no means was the Pronto an apochromat. They showed plenty of color on the moon, bright stars and planets, and also daylight objects (despite Sky & Telescope's review of the optically identical Ranger, which claimed otherwise). TeleVue didn't represent the scope as an apochromat, and I considered it a simple achromat. The false color on the planets was the only thing about these scopes that diminished my enjoyment of them. If I were to get something similar again I would prefer the new apochromatic TV 76.

I used my first Pronto on a TeleVue Gibraltar mount, which was certainly up to the task, but was not overkill in my opinion. The second one sat on a Manfrotto tripod and a TeleVue Telepod head. The Pronto balance plate accessory was a necessity in both cases. The scopes didn't balance worth a darn without it.

The best way of describing my results is to quote from a letter I wrote to Al Nagler about the older scope:

"I recently had my first chance at extended use of the Pronto beneath truly clear, dark, summer skies, with the Milky Way arching high overhead. With a 35mm Panoptic and UHC filter in place, I went hunting for the huge nebulae that don't fit in the field of my larger scopes. I was very pleased by the results. The entire field of Gamma Cygni was a bright intermix of complex light and dark nebulae. These very faint IC objects formed a stark mottling of darkness and light.

I then moved a bit to the north for the finest view of the North America nebula I've ever had. At 14x, it and the Pelican were perfectly framed. The North America was very stark and bright and looked like a ghostly map of the continent, albeit mirror reversed. The Pelican was much fainter, but still obviously there, and quite detailed. Even more impressively, the whole surrounding area was filled with large star clouds and masses of nebulosity, stuff not even plotted in Uranometria. These are things you normally see in deep wide-field photographs of this region, but you don't expect to see them visually. Peering around at all this faint, glowing stuff gave me a curious feeling of intimacy with the Galaxy, of seeing things that are supposed to be hidden or invisible.

I was able to spot the planetary nebula IC 1295 in Scutum, next to the bright globular NGC 6712. M33 was an easy, forthright oval using the 22mm Panoptic, scarcely living up to its reputation of being a challenging object. I also found that I could partially resolve the brightest globulars like M13 and M22 at high powers.

When you combine the Pronto's ability to provide crisp planetary views with its excellent wide-field performance, it becomes a very versatile little package which would be hard to match with any other portable instrument. For an astronomer who needs both extreme portability and pleasing views of all major classes of objects, Pronto is an great choice. The mechanical qualities are also outstanding. Every time I tweak or focus mine I'm reminded that I'm dealing with a high-quality piece of hardware. I'm happy to own one."

Besides that memorable session, I had a lot of fun looking at comets Hyakutake and Hale-Bopp with the Pronto. They were magnificent for scanning the southern Milky Way from dark sites. When I compared the Pronto to the Questar, I found that although the image was somewhat dimmer in the Pronto, planetary detail was about the same, presumably because of the Pronto's greater contrast. Overall, it was a more versatile scope than the Q for visual use because of its potential for very wide fields. It was also one of the prettiest scopes I've ever owned. In its simple, clean, functional way, I found it the aesthetic equal of the Questar. The Pronto was also the perfect companion for the 40mm or 60mm Coronado SolarMax H-Alpha filters, as I discovered while I was caretaker of my former astronomy club's 40mm SolarMax.


I'm pleased (and surprised) to find myself owning a 3.5" Questar. It's a miniature optical and mechanical marvel, the equivalent of a driven, fully mounted long-focus 3" refractor in a case just a bit bigger than a lunch box. I've admired these little jewels since I was a kid, though I overestimated their potential, encouraged to do so by Questar's extremely optimistic advertising. For example, my first serious telescope was an 80mm f/15 Jaegers refractor. I always assumed a Questar would be a step up, since not only did it have a bit more aperture, it was a Questar, not some $150 home-assembled scope. Now I'm not so sure.

In 1976 my mother shocked me by actually buying one of the expensive little things, mostly for use as a birding scope. But she never used it all that much, leading her to give it to in 1993. I've never gotten a cooler gift. This is certainly the only way I, a perennially starving artist, would ever have owned one!

I once did a limiting magnitude test on the Q, coming up with a respectable figure of 12.6. Although I wouldn't use it to probe the dimmer reaches of the NGC, it gives surprisingly good views of brighter deep sky objects, resolving M13 and a few other globulars fairly well at high powers. The hoods of Comet Hale-Bopp showed up well. Besides its limited light grasp, its main drawback as a deep sky scope is its inability to give a wide field of view. You can't get much more than a degree out of it, due primarily to the narrow main baffle and the tiny opening in the mirror, which produces vignetting in any long focus eyepiece. It's a nice scope for quick looks at the moon, sun, and planets, though this can be hindered by the long cool-down time (mine has a Pyrex mirror). As a quick moon-viewer on a bright evening it's a good companion. Lunar images hold up well at over 200X. Planetary detail is abundant enough to give some idea of what's going on, though I doubt many serious planetary observers rely on them. My 92mm Astro-Physics Stowaway refractor completely outclasses it on the planets.

I splurged and added the Questar Powerguide, which replaces the old synchronous motor and AC electrical cord with a DC servo motor powered by an internal 9-volt battery. This greatly enhances the handiness and portability of the telescope.

Nice as it is, I wouldn't recommend a Questar to anyone to whom money means much of anything. If you can afford the price without wincing, it's the best extremely portable complete telescope available. But at over $4000 for a new one, its capabilities are limited for the price. The one attribute which might make it worth part of that premium is its portability. It might be the best eclipse travel scope in the world, a complete system in one small case (if you can count on finding a place to use the tabletop tripod legs).

The TeleVue 76 refractor, or even a used Pronto, is a good substitute if the Q is too expensive. Used Questars are not hard to find, and good ones can be found for around $2,000. Even a somewhat battered one can be restored to new condition by Questar, though this isn't cheap, and may not be worth it if the optics are damaged.


 



I love my 155mm Astro-Physics EDT! But it's not the most portable thing in the world. It takes about twenty minutes to set it up or take it down.

About fourteen years ago I saw the then-new Starsplitter Compact two-pole truss Dob design and thought it might be just what I was looking for: a highly compact, quick to set up scope, ideal for car travel and camping, yet big enough that I need not feel deprived by the absence of the big refractor. I ordered a 10" f/6. It has turned out to be a good choice, though it's not the simple delight my other scopes are. Once everything is working right, the views are really excellent. The Nova mirror was originally a bit astigmatic and had to be sent back. Steve Dodds at Nova did a great job of fixing it. Now it's probably the best mirror I've ever owned. With a small 1.8" diagonal mirror, the deep-sky views easily surpass those of the 155 EDT, while planetary views are comparable, or even superior when conditions are very good.

Alas, getting everything to that sublime state of perfection isn't as easy as I'd like. For one thing, the full-thickness Pyrex mirror takes a long time to cool down, exacerbated by the unventilated design of the mirror box.

The curved diagonal holder is prone to vibration, though if you move the scope gently it isn't an issue. The shroud is well-made, but not well-fitted. It's a bit baggy, quick to sag into the optical path if it gets wet, or blown into it by a breeze. I've modified the shroud to create a tauter fit. The eyepiece unavoidably sticks straight out from the side of the scope, which is uncomfortable when viewing objects at low altitudes. Dew on the secondary mirror can be an issue, but I resolved that by installing a heater. Finally, the scope is too short for me at my awesome height of 6'2". I have to bend down to look through it even when it's at the zenith, and when pointed low I have to practically sit on the ground. I usually stand it on a couple of cinder blocks, which helps a lot.

This is not to say that the telescope is lacking in good qualities! The JMI 2" Crayford focuser is nice. The Astro Systems diagonal holder works well. Overall construction quality is high. The original mirror cell was very poor, but then Starsplitter upgraded them to a metal design, and Jim Brunkella was kind enough to give me one. The scope moves very smoothly. Its portability cannot be faulted. It's impressive to be able to pick up and carry an entire 10" telescope. It only weighs about 50 pounds and sets up in just a few minutes.

All in all, I'd call the scope a worthwhile compromise. It's easy to get it where I'm going. Once it's cooled down and collimated, it gives some of the finest views I've ever had.


The tiny, relatively inexpensive Coronado 40mm SolarMax hydrogen alpha filter is a thing of surpassing splendor. It turns any good small refractor into a portal on the fascinating, dynamic world of H-alpha observing. It could hardly be easier to use, requiring no heater and making no special demands on the telescope's focal ratio. Despite the small aperture, the views are detailed enough to watch for hours as prominences rise and fall. In early 2004 I broke down and bought a used 40mm SolarMax for use on my A-P Stowaway. I also ordered a Coronado Personal Solar Telescope which arrived that summer and which I used for double-stacking the SolarMax, a very powerful yet relatively cheap combination. H-alpha views of the sun are about the most hypnotic thing you can see through a telescope without violating anyone's privacy.

The PST is truly the most sublime $500 an astronomer can spend (well, as long as he already has a good nighttime telescope). Right out of the box it shows bright, detailed views of solar prominences as well as surprisingly fine views of filaments, plages, and other surface features. With the added 40mm etalon it delivers views of even higher contrast, with very dark filaments, luminous active regions, and swirly "spiculation" that looks like iron filings arranged by a magnet. It could hardly be more compact, and its design is elegant and easy to use, especially its ingenious built-in solar finder. What a totally cool thing. Note that even Sun Boy of the Legion of Super-Heroes approves of this instrument.

I eventually sold the SolarMax and now use the PST by itself. Although the views through the stacked instrument were clearly superior, to me the improvement was not worth tripling the cost of the system. Maybe someday when money means nothing to me I will get a more capable Ha system.

"Rust": Earlier PSTs have suffered from objective lenses which develop corroded lens coatings, giving the appearance of greenish or reddish "rust." My unit was no exception. I returned it to Coronado in the spring of 2006 for a replacement lens, which had the same sort of reflective bluish coating as the first. In the fall I noticed the new lens was already showing signs of the same affliction. I sent it to Meade, Coronado's new owner, and received it a month later with a third lens, this one having a transparent blue coating.

I do not consider the PST to be a substitute for a white light solar view, but rather a complement. Several times while using an H-alpha telescope I have also looked through a properly filtered white light scope and found the extremely intricate sunspot groups, delicate faculae, and very fine granulation to be as impressive in their own way as what the PST can show.


Denkmeier II Binoviewer

Having admired the views available though binoviewered scopes for several years, in the spring of 2005 I finally spent the big bucks needed to get into this type of observing. After considering the Baader viewer sold by Astro-Physics, I settled on the Denkmeier II with its three-position Power X Switch because of the flexibility, convenience, and lesser cost of the system.

My chief selection criterion was to preserve the planetary performance of my various telescopes, which immediately led me to the more expensive Denk II rather than the Standard with its less precise prisms. I have seen nothing to indicate I made a mistake. With my 6" refractor, binoed lunar views are hypnotically sublime. Cruising in comfort over the lunar surface at 250X or so, I notice subtle features that escaped me before. Domes, fine rilles, crater chains, wrinkle ridges, and even color variations call for attention from my fascinated eyes. Slewing reveals one strange alien landscape after another, all appearing more real and psychologically convincing than ever before. Lunar maria are covered with wispy streaks and patterns.

Jupiter hangs in space as an intricately-inscribed little ball surrounded by the tiny pearls of moons. Mars can be studied in comfort while waiting for the brief moments that reveal the most detail on its small disk.

Double stars are exquisite with the binoviewer, their perfect images razor sharp, looking almost startlingly real as they float in the field of view.

With the 6", binoed deep sky views are impressive, but are fainter than a single-eyed view, leading me to prefer the one-eyed view with this smallish scope. Star clusters suffer in particular, as the individual stars are clearly dimmer in the binoviewer. With a scope having more light to spare I would probably feel otherwise. Using the binoviewer under truly dark skies makes the dimming considerably less obvious.

Using the scope with the heavy viewer in place is somewhat awkward. It will rotate the diagonal in the focuser if the viewer isn't sticking straight up, unless the compression ring holding the 2" diagonal is firmly locked down. These issues arise mainly when switching from target to target, so a prolonged period of moon or planet watching is less affected. The tall viewer and eyepieces often block the view through my Telrad.

The Power X Switch is very convenient and has a lot to do with making this viewer as practical as it is.

As for eyepieces, I have used only two pairs: a set of 12mm Radians, which were on the short side for the 6" but about right for my Stowaway refractor, and 25mm TeleVue Plossls, which provide a more useful set of magnifications for the 6" with its 1400mm focal length. Both pairs are satisfactory, though much of the eye relief of the Plossls is wasted by the way the eye lenses are recessed in the barrel and the eyecups. This is an issue for me and my glasses. The nicest binoviewer eyepieces I've tried are the 21mm Denkmeiers. I'd like to buy a pair someday.

Losmandy G-11 Mount

This is one of the best astronomical purchases I ever made. My eyes lit up as soon as I saw the G-11 in Celestron's first ads about it. I instantly felt it was for me, an ideal replacement for my solid but unsophisticated Astro-Physics 706 mount. I got an excellent deal from the sadly departed Pocono Mountain Optics on one of the first production G-11s. The current mounts are almost unchanged except for a few details. My mount arrived with a few defective parts, but Losmandy was quick about sending replacements, and has provided good service ever since.

The G-11 has an impressive feeling of solidity. One knuckle rap on its smoothly-machined black anodized aluminum conveys an instant impression of bulletproof strength. Every detail throughout the mount is executed with elegance and precision. The drives are accurate and responsive. With its original RA worm, mine had a periodic error of around 25 arc seconds, which isn't all that great. I understand the later ones are more likely to run in the 7 second range. I have since replaced my worm with a newer "precision" worm, but haven't yet measured the periodic error.

Some people complain about the mount's lack of manual slow motion controls, but I have never found it to be a problem. Some even claim that the mount would be useless without power, but I think that's nonsense. I can push it around by hand well enough for visual use if need be. Note that mine is a manual "Digital Drive" mount, lacking either digital circles or the Gemini goto system. The tripod is very simple yet immensely strong. The polar alignment scope works well.

I did eventually find it necessary to clean out the original grease and replace it with a synthetic, a fairly easy task that makes a big difference. One big advantage of this mount is the ease with which it can be disassembled and worked on by anyone with a reasonable understanding of how it works.

The mount's main Achilles heel was the exposed position of the motors and their wiring, which were protected only by vinyl covers. It was possible to wipe out the RA motor by turning the telescope too far in one direction or by letting the unbalanced head flop over. I installed optional metal motor covers which eliminate that flaw.

I use my G-11 with a 6" f/9 refractor, which is pushing the limits of the mount. Still, it's perfectly satisfactory for visual use. I would be surprised if it could adequately hold a C-14 tube. I've seen this combination in use, but I find it more wiggly than I would want to put up with, especially in any wind.

I upgraded some of the bearings in my G-11 to the current standard, a process which uncovered some weaknesses in the design. I had to remove the worms, a simple enough process, but upon reassembly the drives had a lot of backlash. Adjusting the worms against the gears was a trial-and-error process involving making random changes and then testing the results by looking through the telescope. Luckily that was an adjustment that did not need to be made often. I've also replaced the original RA stepper motor with a new one. The old motors tended to chatter as they operate, pulsing hard enough to possibly introduce some vibration into the image, though I never noticed that myself. The new motor is much quieter and smoother.

As I've grown more interested in imaging I've also become more aware of the limitations of the G-11. My particular mount was problematic for that purpose. I experienced some erratic tracking which I reduced by fiddling with the way the worm, motor, and coupler were installed, aligned, and meshed with the worm gear. Results were inconsistent even with a small, short telescope like my Stowaway on the mount. Even with an autoguider, stars tended to be a bit elongated, even when the PHD Guiding software indicates that it wasn't not doing much work.

I recently solved these problems by adding the Losmandy One Piece Worm Block (OPWB) and brass "precision worm". After some initial difficulty the mount now tracks and guides very well. The RA RMS error tends to be around 0.75", while the total RMS hovers around 1". This performance is good enough to render round stars with my 6" refractor with its 1400mm focal length. This is a 35 pound imaging load that's about five feet long. The G-11 has turned into a surprisingly good imaging mount for this large payload, as long as there isn't any wind to speak of. The G-11 is a fine, relatively inexpensive mount for a wide variety of telescopes.

Desert Sky Astro DSV-1 Mount

I normally prefer German equatorial mounts, but sometimes it's not practical to bring one along on a trip. Sometimes I'm just too lazy to set one up for a quick look. On those occasions I normally used my TeleVue Telepod head, but I decided I wanted something a little bigger and smoother to handle my AP Stowaway refractor. On Cloudy Nights I learned of the DSV-1 altazimuth mount being made by Raul Medina in Phoenix, available at a good introductory price of $160. I ordered one; it took a few months to arrive.

The mount turned out to be nicely made and very solid. Its design is essentially that of a German head with the polar axis sticking straight up and no counterweight. With its standard dovetail clamp, I can now freely use my scope on either the DSV-1 or on my Skyview Pro equatorial without swapping out the dovetail bar, as I had to do when using the Televue head. In use, the mount is pretty stable with this seven pound scope. Any jiggles can be attributed to my tripod, which is on the light side for this combination. I'm able to use it successfully for planetary viewing at powers up to 200X. One convenient feature of an altaz vs. a German mount is that the eyepiece and finder orientation remain the same at all times.

With the scope hanging off the side of the mount and no counterweights, the mount is quite sensitive to being level. If off even a little, the mount will rotate in azimuth. This is the only mount I have which is sensitive to being level. I've also tried the mount with a binoviewer in place on my scope, but this doesn't work very well. I can't push the scope forward far enough to balance it properly, and because of the weight of the bino sticking up at a right angle, any altitude balance is lost as you raise or lower the scope.

The tension of the mount can be adjusted over a fairly wide range using large hand knobs. The mount also comes with a pair of Allen wrenches, though I'm not sure why. As far as I can tell, the Allen screws only hold the mount together rather than adjusting anything.

Other altazimuth mounts of similar design exist. I haven't tried any of them. The DSV-1 seems perfectly fine to me, and is much cheaper than those competing mounts (or at least it was when I bought mine). Many users of small refractors would need nothing else for quick looks and convenient low-power scanning.

Raul also sells dovetail plates, plus accessories for mounting specialized scopes such as the PST.

Telrad

Even though it's big, clunky, and made out of polystyrene, I like the venerable Telrad better than the other available 1-power LED sighters. It's easier to align than most of its competitors, and is among the easiest to look through. Its size makes it most appropriate for scopes of 6 inches and bigger. I use one on my 155mm EDT (sorry, Roland).

Rigel Quikfinder

I use these on my 10" Starsplitter Compact and my 92mm Stowaway because they both need something small and light. The compact base is convenient and solid. Collimation adjustments are predictable. I consider the Quikfinder a very good alternative to the Telrad, and the best choice for very small telescopes, or those with balance issues. It does exhibit more parallax than the Telrad because of its smaller size.

TeleVue Quickpoint

My first Pronto carried one of these, and it did the job perfectly well. It stayed on the scope at all times, and the alignment never budged. Some people complain that the small tinted window makes it too hard to see faint stars, but you're not supposed to use it that way. You look through it with both eyes open and see the dot superimposed against the sky. The tiny exposed circuit board which holds the dimmer control is kinda goofy, but I had no real problem with it. To me the biggest annoyance was the huge green billboard-like logo on the side, right above where it says "Daisy"...

TeleVue Star Beam

One of these high-end toys came with my second Pronto. Though certainly the classiest of all red-dot sighters, and the only one made of metal, I might not pay $200 for a new one. I did enjoy owning and using one, and miss it.

Astro-Physics Maxbright 2" Diagonal

Oh-la-la! You wouldn't think that something doing so unglamorous a job as reflecting light through a ninety-degree angle could be sexy, but this thing is. It is beautifully designed, carefully thought out, immensely solid, and with its advanced high-efficiency dielectric coating should last for decades. The TeleVue unit is nice too, but this is the one to get. It might be the only chance for a lot of people to own any Astro-Physics optical equipment at all!

TeleVue Radian Eyepieces

I consider the Radians to be the overall best line of eyepieces I've seen. The balance of field size, eye relief, sharpness, and contrast is excellent. With the consistent 20mm eye relief across the line, the shorter Radians offer phenomenal comfort for planetary observation. I own the 12mm, 8mm, and 5mm, and they are cornerstones of my eyepiece set. They perform well at objective focal ratios as fast as f/4.

TeleVue Type 6 Nagler Eyepieces

I have two of these, the 7mm and the 3.5mm, and they are vying with the Radians for my affection. They're small and compact, and their immense field of view is gorgeous. They don't produce the "kidney bean" or blackout problems that keep me away from the other Nagler designs.  The 12mm eye relief is not overly generous, but is usable even with my glasses on (which are thin).

Stellarvue F50 Finder

I bought one of these highly regarded 50mm finders because it offered the features I wanted: good optics, a right-angle correct image Amici prism, interchangeable eyepieces, good focusing mechanism, and a rotating eyepiece position. Since Stellarvue's many fans encourage treating the F50 more like a small telescope than a mere finder, I decided to test it as such. This involved using it with a variety of eyepieces. I don't expect to be using the included 23mm eyepiece very much. Not that it's a bad eyepiece, but at 8.7X in the 200mm focal length scope, it gives an exit pupil of 5.75mm, which is more than my eyes can accomodate. Consequently, when viewing through this eyepiece, stars look noticably dimmer than they should, since some of their light is falling on my iris, not passing through my pupil. I also removed the reticle from this eyepiece, for a number of reasons. For one, it's not necessary. I can already tell when something is in the center of the circular field. Secondly, as the instructions state, you can barely see it in the dark anyway, unless it's illuminated, and mine isn't. Third, since it's useless, there's no sense in letting the plastic disk gobble up any light.

My tests mostly involved a 3.5mm Nagler for 57X, and a 12mm Radian for 16.7X. The Radian gives a true field of 3.6 degrees and a 3mm exit pupil. This results (for me) in brighter stars, a darker background, and deeper penetration than the stock eyepiece. The field is smaller than the original 6 degrees, but is still big enough for a finder, especially when used in conjunction with a Telrad. If I felt like spending $200 or more on an eyepiece for a $120 finder, my first choices would be the 14mm or 18mm Radian.

I examined Sirius at 57X. Yes, I saw some violet color error at this power, hardly a surprise for an f/4 objective. I could also see a faint spike radiating from both sides of the star, an artifact of the Amici prism. This was quite subdued and not obtrusive, much better controlled than I've seen from some other Amici diagonals. I might not notice it at all on a star which was much fainter. I performed a quick star test using Polaris. The Fresnel pattern was neat, round, and well-defined on one side of focus. On the other side I could see a vague dark line crossing the pattern, again an artifact of the angle of the Amici prism. This star test was much better than any I ever got from the 60mm "Baby Brandon" refractor which I also use as a finder, and which has some serious optical issues.

I looked at Saturn, which revealed a tiny ringed image. When focused for the best sharpness, a small disk of spurious light expanded out of the planet, compromising the view. I suspect this too is due to the presence of the Amici prism, which are really not well suited to high power astronomical use. Luckily, I don't intend to do much planetary observing with the F50! Titan was dimly visible. Finally, I could barely split Gamma Leonis, or Algieba, at this power.

Dropping down to 16.7X, I viewed a number of deep sky targets to assess the F50's usefulness as an actual finder. I was quite pleased by what it could reveal. Sky conditions were only fair that night. My site is somewhat dark, but the sky had large areas of thin gauzy clouds which muted the stars if they snuck up on me. Nevertheless, the F50 showed crisp fields full of sharp stars. I had a surprisingly extensive view of M42 which included the full loop of the curving outer arms. M1, the Crab Nebula, was easily visible as a little smudge. The Double Cluster was a pleasingly sparkly assemblage of stars, as was M35. Most surprisingly, I could even see NGC 2158 as a tiny blur just to the side of the big cluster. Naturally I also had nice views of big clusters like the Pleaides and Beehive.

As I sat there looking through this tiny telescope, contemplating all it was capable of showing, it occured to me that people who claim you can't really see anything through relatively gigantic 3" or 4" telescopes may be a tiny bit spoiled and jaded.

Mechanically, the F50 is pretty nice, with a couple of caveats. One is the main lens cap: it's lame. Very loose, it easily falls off. The helical focuser is nice to have, but overly stiff. At 32 degrees Fahrenheit, it became so hard to turn that I had to hold on with both hands, lest I unscrew the whole assembly from the diagonal.

Since this test I bought a used 15mm Orion Expanse widefield eyepiece, looking for an economical way to get a higher power from this finder. It turned out to be a poor choice, showing highly astigmatic stars in the outer parts of the field. Even in my long-focus Questar telescope this eyepiece shows astigmatism. It's a good example of what you get when you try to go cheap on a wide-field eyepiece: not much. While usable in the finder, the view is quite ugly, and does not properly represent the views which are possible through this little scope. I find it unfortunate that these finders are made with objectives of f/4 or even faster. It keeps them short and light, but it means they need eyepieces twice as expensive as the finders themselves to perform at their best. I vote for f/6.

Overall, the F50 is the most sophisticated, best working 50mm finder I've seen.

VERNONscope "Brandon" 94mm Refractor

I owned one of these from 1989 to 1991. It was a handsome thing, with its baby blue tube, wooden tripod, and classic Unitron equatorial mount, but ultimately the only thing I really liked about it was the Christen triplet objective. In other respects I found that it wasn't well designed for actual use. Permit me to enumerate its deficiencies:

The scope came with an impressive grey graphite case which nevertheless was too short to hold the fully assembled tube. To store the scope you had to unscrew the dewcap, remove the drawtube, and stick them in separate compartments in the case.

The 2" Unitron focuser looked better than it worked. The clamps were not very positive and weren't strong enough to lock down the focuser for any kind of photography. The drawtube was not blackened internally, but chromed, making the telescope useless when used straight through, since the shiny tube bounced all manner of stray light around.

The finder was the worst I have seen. Stars were horrid astigmatic messes, so poor that the finder was nearly useless.

The mount charmed me as someone who still has a Unitron catalog from the 70s, and it supported the scope adequately, but I still found it poorly designed. The multiple clamps and slow motion controls were a confusing forest of stalks to navigate by feel. The declination control was far too coarse to be of any use for photography. The clock drive had to take up a lot of slack before it actually began to move the scope. The mount head came in a cool wooden case though.

This scope would have made a great ornament, and it could certainly be used for successful viewing, but too many deficient details and instances of poor ergonomics led me to sell the instrument with only mild regret. The nice lens was similar in design to the original Christen triplet, and showed some color, but was good enough for all but the pickiest user.

78mm f/6.5 Jaegers Refractor

Short-focus achromatic refractors have been a bit of a fad for the past few years, largely due to the popularity of the cheap imports from China. Since I am wise beyond other men, I have been using small short refractors for the past 30 years. They all came from those curious, modest, pumpkin-patch sincere A. Jaegers catalogs, through which newer amateur astronomers have not been privileged to pore. Jaegers refractors could not be purchased complete, but only as parts to be assembled. My first was a 1972 3.25" f/15, my first serious telescope. The telescope, complete with an Edmund equatorial mount and two Brandon eyepieces, cost $180 (I would have gotten a 4" if I hadn't splurged $36 for the pair of Brandons).

In 1974 I built a 3" f/6.5 for targets like the Pleiades nebulosity, the Veil, and the North America Nebula, objects which amateurs were just then realizing could actually be seen. It was a fine little scope which I would probably still have save for a shameful mishap. I managed to fracture the objective while trying to remove the cell from the tube (I will say no more). I eventually sold the poor thing as a finder on a larger scope.

In 1981 I decided to try a longer version of this sort of scope, an f/8.6, hoping for better performance. It was a decent enough scope but didn't really suit my purposes, being physically too long to ride comfortably on the cheap camera tripod I was using as a mount. So in 1983 I sold that lens and adapted the tube assembly to hold another 3" f/6.5. I still have this scope, my only relic of the days when all my scopes were assembled by me (since then I've realized that other people are equipped to do a better job than I am).

The lens is okay, but not as good as the original, showing a bit of astigmatism at high powers. I have steadily refined the tube assembly over the years. I recently flocked it and added tube rings and a dovetail bar. At this point its biggest weakness is the clunky 2" focuser, which is similar to the old red-knobbed Jaegers focusers, but came instead from a strange long-defunct company in the Philadelphia area. I have improved it by adding Teflon tape to take out some of the slop.

In comparing the scope to a TeleVue Pronto, the Jaegers shows a noticeably brighter image, color correction which is only barely worse, and similar levels of planetary detail. This venerable scope's shining moment came when I used it to stare at the phenomenal beauty of the solar corona during the 1991 eclipse in La Paz, Mexico. It has also played a role at various partial and annular eclipses, and served as a finder on my old 14.5" Dobsonian.

It's too bad today's observers don't have the option of assembling refractors from Jaegers.

14.5" Sky Designs Dobsonian with Galaxy Mirror

In 1989 I read an ad for an unused 14.5" f/5.5 Galaxy mirror in "The Starry Messenger", that quaint newsprint relic of an earlier time. The ad inflamed me with aperture fever, compelling me to rush off and buy it. With this massive full-thickness slab of Pyrex in my possession, the next thing was to obtain a structure in which to put it. I selected Sky Designs in Texas, a very small shop specializing in plywood truss Dobs. Bob Combs, the owner, agreed to take on the task. Several months later I had the completed telescope in my hands.

The structure looked decent and was quite functional, albeit crude in certain ways. For example, it didn't really have a mirror cell. The mirror rested on nine little wooden hemispheres which were in turn attached to a round sheet of some flexible material. Allen screws set into the back of the mirror box bore against this sheet and tilted the mirror. Cheap, simple, and reasonably effective. The diagonal holder was only slightly more sophisticated. The diagonal mirror was glued to a wooden dowel which was passed through a cylinder which was attached to the spider vanes. Six screws in this hollow cylinder bore against the dowel in a finderscope ring sort of arrangement and were responsible for alignment of the diagonal. It was a more workable arrangement than it sounds. The focuser was a large 2" helical made by Kevin Medlock.

The most disappointing thing about this structure was that the mirror box contained a large quantity of lead to balance the nose. This meant that the mirror box weighed around eighty pounds...near the limit of my willowy frame to pick up and place into the hatch of a Toyota Celica. Overall, the scope lacked the sophistication and the optimization which is typical of today's higher end Dobs.

The telescope gave me the best views I've ever had using a telescope of my own. At the Winter Star Party, its planetary performance was equal to any and better than most. Jupiter at 500X was a breathtaking maze of detail, overwhelming the view in any 6" refractor. The moons showed disks which looked as substantial as a distant Mars looks in a lesser telescope, with Ganymede showing definite detail. The performance of the f/5.5 mirror was very pleasing (I'm not fond of very short focus mirrors). Deep sky views were everything you'd expect from a scope of this size.

Back home in upstate New York, under lesser conditions, the reflector's supremacy was less apparent. Seeing had to be very good indeed for planets to be seen at their best. The mass of lead and the closed-back mirror box made cooling difficult. With these issues and the sheer difficulty of transport, the big scope did not supersede my 6" refractor.

So, although this was the biggest telescope I've ever owned, and the most powerful, I sold it after a couple of years. Every now and then I miss it a little bit. Maybe someday when the time is right I'll get something that will equal or surpass it.



Words copyright by Joe Bergeron.