Wow: (adding material in 2018) I've had this scope for 13 years! So much has changed. The whole wave of Chines scopes for example. I have used it primarily on my C14 because when doing solo refractor work I have used a 5" apo (FS128, then GT130). I have had some great experiences solar viewing with it, using a Daystar Quark h-alpha. It's focal ratio is a little below optimal in that application, but the views of have been excellent (if you buy a refractor *specifically* for dual solar/night time use, get an f/7.5 if you can). When I bought this scope Daystar quark didn't even exist! The light weight of the scope gives it a ticket on top of the C14. My SV4 102 f/6.4 weighs 50% more, counting rings and dovetails on both. Too much mass I'm afraid. These little scopes are very rare on used market because most owners correctly figure the China apos won't let them get for this scope what they're worth. (I have seen it outperform low cost triplet apos). Planet performance is very good, you see details in bands of Jupiter and GRS, etc. I confess though that I mostly use it for wide field, because, sitting on top of a C14, I don't need it for planets. I'm afraid I've aged a good deal more than this little scope. I have no plans on selling it. Greatly pleased with Vixen in general and two years ago acquired the Vixen ED81s (f/7.7).

My original review in 2005:

Note: the price of $1200 is a typical used price; the OTA went for $1650 when new. The f/6.5 ED102SS was pulled from production due to work hazards in the factory related to the glass. Vixen will reintroduce a short fl refractor later. Apparently getting the right glass at reasonable price is not easy and for a while the company has gone back to f/8 and longer fl refractors.

I feel that I am just getting to know this refractor and what it can do after a dozen outings with it. I did replace the focus mechanism--it was very smooth, but the default 2" diagonal adapter used set screws and I prefer brass compression rings. With a Moonlite focuser the scope is a very classy piece of equipment.

I cannot at this time of the year try it on the Antares double which is so low that in my part of the world no one ever splits it anyhow. I have split the triple Iota cass and the four major Trapezium components in M42 were easily visible at 17x. I don't think one can see E and F at that magnification in any scope, at least not in upstate NY.

This scope excels on the famous wide field objects: the Perseus double cluster, both sides of the Veil at once, and my new favorite, the N. America nebula, which shows exquisitely in OIII and very well in white light. I have caught good surface details on Mars. My performance comparisons have included an SDF Genesis and NP101, as well as an AP Traveller. Unlike the other reviewer I find no significant differences between the Vixen and these other well known refractors.

The theoretical field of view is 4.25 degrees versus 4.5 for the traveller and 5.5 for NP101. Even with the Moon Lite focuser, the cost is half these other scopes so I consider it an excellent deal. It is a real treat to cruise Cassiopeia in this scope and I very much enjoyed objects such as IC 1396 (central triple star easily visible at 17x) and the trip from the Veil to the Rosette Nebula, which includes rivers of dark lanes.

My only comment on color correction is that a careful assessment showed that most of the color I was seeing came from eyepieces (such as the 24 Pan) and a cheap barlow. When I borrowed a powermate barlow and a different eyepiece the color wasn't there. I have viewed Mars at 200x or so and in focus there was no color. This is a great short fl scope, and if you want a fancy focuser it can be gotten aftermarket. Be careful when purchasing: be sure you are getting the f/6.5 ED 102SS: there is an ED 102S which is f/9 and a different instrument altogether.

When I set out to buy a used apo I originally sought an SDF Genesis but due to the vagaries of the used market ended up with this instead. I think it's a great deal, but after looking through the Traveller and the NP101 and the Genesis SDF in my club, I am glad to say that there are a number of fine choices out there. The ED 102SS delivers a very high quality wide field experience and will take magnification too.

Overall Rating: 10
Optics:10 Value:10
Weight: 10
Date: 05/07/2018 08:29:35 pm PST

Replies: 0

Very lightweight for this aperture. Excellent optics. I used this jewel for about seven years, visual use, while waiting for the GT130 from Astro-Physics. I did replace the four inch focuser with a Moonlite, the OEM focuser had issues. Very sharp views up to 300x on planets which is as high as I cared to push it.

I sold it to my best friend when the GT130 arrived because neither of us wanted to see it leave the area. He put a Feathertouch focuser on it and uses it for imaging.

I was attracted to the GT130 because at f/6.3 I figured it would be wide field king, and it is. But I find I use the GT130 with a 30mm eyepiece that gives 27x, whereas I used to use the Tak with a 40mm eyepiece that gets 26x. In other words, I some how got accustomed to the f/8.1 views. And of course my own personal astigmatism makes the 20x offered by the GT130 a bit hard to use.

At 300x on planets, you can get there comfortably in the FS128 with an XW 3.5 mm eyepiece. To get to 300x in the GT130 you have to use a 2.5 mm XO or similar. That's a bit more eye strain.

These days when you pay a lot of money for an apo the tendency is to "go short." You may find however that you are happier at f/7.5 or f/8 overall. It's hard to resist pumping the power on planets when they are optimally placed. That said, the tube is longer. Weighing the OTA as I configured it with a Moonlite, and comparing the GT130: they were the same! Leastaways on my scale. The GT130 feels heavier in part because it is dense, much shorter.

Anyhow this is probably the classic fluorite visual observer's scope and you will enjoy it a great deal. The guy who sold me mine said he sometimes missed it but was doing OK....with his TEC 140. The fluorites from TEC and Agema that are coming out (2018) may well bring fluorite back into relative popularity so we'll see. Anyhow it was a great privilege to own and use an FS128.

Overall Rating: 10
Optics:10 Ease of Use:10 Value:10
Weight: 10
Date: 05/07/2018 08:12:23 pm PST

Replies: 0

Recently in Montreal and took a trip to the Maison de l'Astronomie. There were several people there and the guy that I talked to at first was all hustle: he knows how to move newbies into an inexpensive equipment configuration. He kept throwing different configurations and price points at me whereas I was just trying to get some information about a mount. Still, I let him do his salesmanship because I rarely get a chance to be inside a brick and mortar astronomy shop. After we chatted a bit and he understood what kind of rigs I already have he
slowed down a bit and showed more technical expertise. I have in fact flirting in slow motion with the idea of getting an ASGT go-to mount for portable applications. I was
assured that it worked fine in the cold, and Montreal is a good place to ask that question. On further discussion he contended that the tolerances on a mount like the G11 are too tight for extreme cold and that the ASGT did better without needing adjustment or supplementary heating. I can think of G11 users who would not agree but there was at least a logical presentation there.

Downstairs the Maison has a lot of Skywatch, Celestron, and a row of Vixens. Sales rep said that Vixen was "losing" some of its quality as it became more Chinese (I hope not). The upstairs was for used scopes. That place
was fun, you have to imagine a room just stuffed through with telescopes and even a four or five inch OTA on the floor where it might get stepped on, sort of casually strewn about in the expectation that you know what you're doing walking around in an astro shop. Sales rep said (this is 2008) they had stopped carrying Meades because of too many complaints from customers. There were however two LX200 used units for sale upstairs.

Aside from the Celestron CGE there were no "higher end" mounts on the floor that I could see. Sales rep said Losmandies were ordered for customers as needed, and there were no really fancy pants Tak mounts. There was not even a Vixen Atlux, but there was a smaller go-to
Vixen unit.

Unfortunately I was pressed for time; I could have spent several hours there looking at the offerings. The selection of books and charts was well put together.

I think if I lived in Montreal the Maison de l'Astronomie would be a resource I would use. I have met a few amateurs from the area and they have indicated that the company is an active part of the local astronomy community. It must be nice to have a real astro shop in
one's locale. The Maison supports star parties in the region. As with most situations in Quebec our conversations were all in French but the shop functions in English too. It would be unusual for a U.S. citizen to need to order from the Maison but I believe they are serious about offering products that work at a good price.

Overall Rating: 10
Price:10 Service:10
Weight: 10
Date: 07/22/2008 01:09:09 pm PST

Replies: 0

Excellent eyepiece with superb correction. Very bright with light transmission at 96%. No pincushion. A capable eyepiece for deep sky and planets.

Pentax is rigorous with dealers about listing price discounts. Most XWs will sell for about 10 to 12% less than the price you see on the web site. In other words there's the list price, the dealer price, and the real price if you call. Don't order by "clicking through" because you'll be charged the web site dealer price. Call a few vendors first.

Overall Rating: 10
Optics:10 Value:10
Weight: 10
Date: 07/21/2008 04:18:20 pm PST

Replies: 0

This is AP quality and the best of the best in terms of carrying your mount with engineering precision and style. They typically sell used for about $3,300, and are not easy to find, but occasionally out there. The downside is that by the time you do the azimuth adjustment upgrade, the Dec worm upgrade, buy some counterweights, a mounting plate, and a pier, you'll be out at least double the used price. But even so with all the accessories a contemporary AP900 GTO will cost substantially more, you'll need the accessories for it too, and be north of $10k. These are excellent mounts fully capable of photography.

Although the mount is definitely a big step up from the Losmandy G11, it has several downsides. First, the altitude adjustment handle is a nightmare compared to Losmandy systems. Difficult to get torque on the adjustment handle from behind the mount while polar aligning: AP even makes a little handle to be used as a lever, a real pain to use because it can't go all the way around forcing short turns. AP's latest mount, the Mach 1, wisely decided to imitate the Losmandy format for altitude adjustment.

The second defect is that the digital setting circle system is poorly designed. It has to be completely removed in R.A. in order to polar align. That's OK, but the process of removing and re-insertion puts contradictory demands on the engagement of the encoders with the mount. The aluminum wheel AP uses to make a pressure fit around the encoder shaft is a poor solution. After not much use, the ductility of the aluminum stretches the aluminum and causes slippage of perhaps twenty to thirty arc minutes. If you're using a wide field refractor it's not such a big deal, but in other applications, like a C11 or C14, or a long focal length Mak, it is a big deal indeed.

It is possible to fix this problem but too detailed to recount here. A complete photo essay is on the Argo_Navis Yahoo groups. The sum of it is that after using a variety of systems I have found that, as a digital setting circle guy, the Losmandy G11 is actually better designed.

I use this mount, I love this mount, but it took quite a bit of doing and some money to get it to meet my requirements. If you do get this mount, fix the encoder wheel problem (which requires a user modification of the OEM part), and combine it with Argo Navis you'll get pointing accuracy superior to the AP go-to systems, which at this writing still do not include mount modeling. You might also consider upgrading to 10,000 tic encoders since the 900QMD series was all 4,000 tics.

AP has not had as much customer demand for pointing accuracy as one might think because the clientele favors wide field refractors and relatively bright objects that don't put a demand on pointing accuracy. The people that DO want pointing accuracy are typically imagers and they invariably have worked around the problem by putting T-point or similar software on their laptops.

So, at least of this writing, you are actually better positioned to get pointing accuracy with the older mounts if you don't want to use a laptop in the field. The AP paddle system in the go-to mounts does not (yet) rival the capabilities in Argo Navis and in PC based systems like T-point.

The mount is very steady under high load and does something my G11 could not do: carry a C14+102mm refractor.

It's a wonderful system but I can't quite bring myself to give it an "overall" rating of 10 because of the flawed digital setting circle design, which put a premium of looks at the expense of functional accuracy. On this limited dimension, and the altitude adjustment, the AP takes a back seat to Losmandy (superior on steppers and worm, which are more critical). And the AP digital setting circle design is certainly better than some of the improvisations made in the 90s, such as the JMI hardware for Vixen. (Never get JMI digital setting circle hardware for Losmandy mounts). It's just that on this point the AP design is a very definite second best and that's somewhat surprising. In addition, it is a chore, every time one sets up, to screw the polar scope in and then take it out again.

On the other hand, with Argo Navis and 10,000 tic encoders you will get pointing accuracy of 3 to 5 arc minutes, and that's about as good as it gets.

Overall Rating: 9
Performance:10 Ease of Use:8 Value:10
Weight: 5
Date: 05/27/2008 06:34:07 am PST

Replies: 0