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Astro Telescopes 102mm f/11 - first light report

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#1 bobfowler

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Posted 14 September 2009 - 09:41 AM

I bought this scope on September 5th at Hands On Optics, which is why the weather was so *BLEEP* until the 13th. :shocked: I had <10 minutes with it the day I bought it before the clouds completely rolled in, so last night was the official first light. My observing session was at Sunnyside Rec Area in Middletown, NJ.

I have the OTA mounted on a brand new Celestron CG4. The OTA weighs in at just about 12 pounds, so combined with the 46 inch length, puts it pretty much at the limit of what the mount can comfortably handle. (see note below)

The scope is a multi-coated achromat doublet. The lens cell is fully adjustable and was dead-nuts on from the factory. The OTA is well baffled and features a rotating dual speed Crayford focuser and sliding dew shield. Dual rings and a 7.5" long Vixen type dovetail round out the package as delivered. I'm using a Telrad for a finder, but will probably add a Stellarvue F50 RACI finderscope soon.

The scope star tests beautifully, both inside and outside focus exhibit expected results from a well designed and adjusted achromat. As one might imagine on an f/11 achromat, false color is non-existant on most targets with only slight, and I mean SLIGHT "achromat blue" on very bright targets. Using a minus V filter completely eliminated that chromatic issue in visual use. Targets included Jupiter, M13, M92, M57 (which was so beautiful through this scope), M31, M22, M29, M39, and M8. EP's used for testing were a Meade Series 4000 20mm (56X), a Celestron 40mm Plossl (28X), and a BO TMB 9mm Planetary (125X). The 40mm EP was used only as finder when my Telrad dewed over! I used my Stellarvue D1031ED 1.25" diagonal. Atmospheric conditions weren't great, so I didn't push the magnification any higher than 125X.

My only gripe with the scope is the focuser. I knew when I bought it that the slow speed section of the Crayford had "issues", and even after a complete disassembly/cleaning/re-lube, it feels a bit "chunky". It's a LOT better than it was, but I have a feeling I'll be spending a lot more time with it apart on the bench. With the slow speed portion of the focuser off, it is smooth as silk, so the problem lies somewhere in the ball bearing mechanism. Gary Hand is working on the problem and I have confidence he'll get it sorted out, but impatient me couldn't wait and I bought the scope even though he said he wasn't happy with the focuser. I suspect that the problem is the profile of the small shaft that engages the 3 ball bearings that transmits the rotational force to the main focus shaft. During the rain this past week, I made some adjustments to the tension inside the slow speed mechanism which resulted in huge improvements, but the mechanic in me wants to play with that shaft some more.

Lessions learned: Balance on the CG4 mount is critical for an OTA of this length. When I first set up, I was a little tail heavy and the mount was very unstable when focusing. Adjusting the position of the OTA on the mount cleared that right up. Last night, I ordered the dual axis drives for the mount, as well as the Orion 16" SkyView Pro Telescope Mount Extension (thanks for the tip Kit!) and the CG4 polar alignment scope. The 16" extension is an absolute must (for me) as I found myself sitting on the ground, hunched over, to look at targets near zenith. The drive motors are also necessary as you need "monkey arms" to operate the RA slow motion controls to track from the eyepiece. I was able to polar align well enough for visual use without the polar scope, but since I was already spending money, what's another $35.00 or so.

All in all, the scope is a winner. I wanted a long focal length 4" refractor for splitting doubles and planet watching, and f/11 fits the bill beautifully. Once the focuser issue is ironed out I'll be even happier. Regardless, it was an excellent buy.

note: The decision to go with a CG4 vs a CG5 was that I wanted a manual EQ mount to which I could add motors, I have no need for goto, and since I'm a visual observer, didn't need auto-guider input capabilities.

#2 Doug76

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Posted 14 September 2009 - 12:56 PM

Nice to see a good NEW achro being talked of here. Sounds like a good one.
I found when I had a CG-4 that it was much more stable when used as an Alt-Az mount. Of course with you getting tracking motors, this isn't an option for you.
A CG-5 would carry it well.

#3 Rat

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Posted 14 September 2009 - 03:43 PM

Any pics of the OTA?

#4 Doug76

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Posted 14 September 2009 - 05:56 PM

Yeah, pictures please.

#5 m9x18

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Posted 14 September 2009 - 06:05 PM

Nice report Bob. Thanks for posting this. I hope you have many nights of pleasure and enjoyment with that scope.

#6 wprince

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Posted 14 September 2009 - 09:19 PM

Hmm... I don't see an F11 102mm achro on the Hands On Optics website. Is Gary Hand planning to sell any more?

#7 bobfowler

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Posted 14 September 2009 - 10:13 PM

Hmm... I don't see an F11 102mm achro on the Hands On Optics website. Is Gary Hand planning to sell any more?


He has a few more (3 I think) at the moment. AFAIK, he's still working out the bugs in the focuser. If you go to the Astro Telescopes web page , they are listed as a "coming soon" item. Vic Maris (Stellarvue) had a major hand in the design of the scope, but since he no longer sells achromats, his involvement is pretty much over. The scopes are made in the far east and distributed in the US only by Hands On Optics. Vic did get a few samples of the scopes which he sold to Stellarvue "All-Stars" members, the rest of the initial run went to Gary. Joe Martin got one from Gary about a week before I got mine. I don't know if any of the others are still available, but I do know that as of a week ago, Gary was still working out the kinks in the crayford. The picture I'm posting is one that Vic sent out when he announced the scope to the All-Stars members. I haven't shot any of mine yet...

Attached Thumbnails

  • 3334340-102achro 100.jpg


#8 Clive Gibbons

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Posted 14 September 2009 - 10:38 PM

Hmm... I don't see an F11 102mm achro on the Hands On Optics website. Is Gary Hand planning to sell any more?


He has a few more (3 I think) at the moment. AFAIK, he's still working out the bugs in the focuser. If you go to the Astro Telescopes web page , they are listed as a "coming soon" item. Vic Maris (Stellarvue) had a major hand in the design of the scope, but since he no longer sells achromats, his involvement is pretty much over. The scopes are made in the far east and distributed in the US only by Hands On Optics.


The 4" f/11 achro was designed and manufactured by Kunming United Optics for quite a while before any US vendor decided to carry it.
Link.

#9 o1d_dude

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Posted 15 September 2009 - 01:05 AM

What kind of focuser "issues", Bob?

#10 Trever

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Posted 15 September 2009 - 01:22 AM

Very nice lookin scope. We need more quality Achros out there.

#11 bobfowler

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Posted 15 September 2009 - 01:52 AM

What kind of focuser "issues", Bob?


Apparently, some of them (like the one I bought) came in with very rough, almost grinding sounding Crayfords. The problem is in the slow speed mechanism because with it removed, the focuser is silky smooth - or at least as silky smooth as a single speed can be. I took mine home knowing full well that I had to work on the focuser to make it right. When I called HOO the day before I drove down from NJ, Sherry warned me of the problem, but I decided to go pick one up anyway - how tough can a Crayford be to fix, right? I spent some time working on mine, and while it's still not quite perfect, it's 2000% better than when I started. I've been in touch with HOO about the steps I've taken to fix mine and am keeping them in the loop. I just don't want people to think that Gary tricked me into buying a scope with a bad focuser, quite the contrary, I was a persistent PITA and was willing to buy it with that problem knowing it could be resolved in my shop.

#12 o1d_dude

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Posted 15 September 2009 - 07:27 PM

Interesting to hear, Bob.

The slow/fine motion control is awfully smooth on mine but I have on occasion felt a grittiness on the coarse focusing. Not a regular occurrence but something I have felt a few times. If it were in the fine focusing area, I'd be a bit more concerned but at this point, it's still just a "hmmmmm...." kind of thing.

#13 bobfowler

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Posted 16 September 2009 - 11:02 AM

I'm giving serious consideration to adding the Orion electronic focus controller which would eliminate the whole slow speed thing on the Crayford. The speed control varies from 7 seconds per revolution to 28 seconds per revolution, much finer than my fat old fingers can do...

#14 mathteacher

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Posted 20 September 2009 - 09:20 PM

I looked through Old Dude's model yesterday. Very nice optics on Jupiter and smooth focuser. I liked it :)

#15 GShaffer

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Posted 21 September 2009 - 12:34 PM

HI Bob

This focuser issue sounds identical to the one experienced by so many (including myself) with the GSO crayford....Likely it is a GSO given the scope it is on.....

There is a fix which was put out there by Pollux Chung that will do one of two things.....totally cure it or make it considerably better....In my case it helped a LOT but didnt completely eliminate it.....Even if it is not a GSO branded focuser it sounds so much like the same problem I am betting it would help.....See link below:

http://www.agenaastr...cles.asp?ID=179

While it didnt totally cure the issue in my case it has for others and it did make a drastic difference for me.

What kind of focuser "issues", Bob?


Apparently, some of them (like the one I bought) came in with very rough, almost grinding sounding Crayfords. The problem is in the slow speed mechanism because with it removed, the focuser is silky smooth - or at least as silky smooth as a single speed can be. I took mine home knowing full well that I had to work on the focuser to make it right. When I called HOO the day before I drove down from NJ, Sherry warned me of the problem, but I decided to go pick one up anyway - how tough can a Crayford be to fix, right? I spent some time working on mine, and while it's still not quite perfect, it's 2000% better than when I started. I've been in touch with HOO about the steps I've taken to fix mine and am keeping them in the loop. I just don't want people to think that Gary tricked me into buying a scope with a bad focuser, quite the contrary, I was a persistent PITA and was willing to buy it with that problem knowing it could be resolved in my shop.



#16 GaryM

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Posted 04 October 2009 - 06:43 PM

Anyone know how to get the dew shield off of one of these things? Mine was damaged and I hope to exchange it for a new dew shield...

Best,
Gary

P.S. What a beautifully made scope!

#17 bobfowler

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Posted 05 October 2009 - 12:08 AM

Anyone know how to get the dew shield off of one of these things? Mine was damaged and I hope to exchange it for a new dew shield...

Best,
Gary

P.S. What a beautifully made scope!


The dew shield should unscrew from the ring at the base of the shield. I haven't had to remove mine (yet) but that's the way they are usually connected.

BTW - I adapted an Orion electronic focuser to mine. What an improvement! I took the focus knob off on the slow speed side and mounted it there. It wasn't a direct bolt-on, but the mods didn't take long and it works like a champ.

#18 Trever

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Posted 05 October 2009 - 01:04 AM

I received mine on wednesday but they shorted me the losmandy dovetail I needed for my mount. I am still waiting and it may be mid week before I will get it. It is a shame too as I had great skies that night.

#19 peleuba

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Posted 05 October 2009 - 04:40 PM

The scope star tests beautifully, both inside and outside focus exhibit expected results from a well designed and adjusted achromat. As one might imagine on an f/11 achromat, false color is non-existant on most targets with only slight, and I mean SLIGHT "achromat blue" on very bright targets.


Scope looks like a winner. Gary Hand is my local dealer. Though I have not purchased much from him, he's an interesting guy to meet and talk with. I recall reading about this telescope few months back (maybe longer). KUO will even customize the paint job if enough are ordered.

When you star tested, did you use a green filter? If not give it a try as these achromats are nulled in green light - it will clean up your Fresnal pattern nicely.

I do not mean to pick a nit, but what does a "well designed and adjusted achromat" really mean? Color correction, spherical, smoothness etc? I've heard this phrase for years, but have never heard a satisfactory explanation. If its color, there is no range of color correction in telescopes that use normal crown and flint type glasses (Achromats) regardless of manufacturer. Focal ratio will be the determining factor vis-a-vis color correction and not glass type etc.

You mention Vic's "All-Star List", what is that? I am interested in a SV finderscope... Do I need to be part of the All-Star List to purchase? You madeit seem like members get the best deals...

Thank you for the report and hope you get the focuser issue fixed. I think this focuser is used on several different OTA's so there should be some info you could dig up on it.

#20 bobfowler

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Posted 08 October 2009 - 10:35 AM

<snip>
When you star tested, did you use a green filter? If not give it a try as these achromats are nulled in green light - it will clean up your Fresnal pattern nicely.

I do not mean to pick a nit, but what does a "well designed and adjusted achromat" really mean? Color correction, spherical, smoothness etc? I've heard this phrase for years, but have never heard a satisfactory explanation. If its color, there is no range of color correction in telescopes that use normal crown and flint type glasses (Achromats) regardless of manufacturer. Focal ratio will be the determining factor vis-a-vis color correction and not glass type etc.

You mention Vic's "All-Star List", what is that? I am interested in a SV finderscope... Do I need to be part of the All-Star List to purchase? You madeit seem like members get the best deals...

Thank you for the report and hope you get the focuser issue fixed. I think this focuser is used on several different OTA's so there should be some info you could dig up on it.


I didn't use a green filter during the star test, but I have since you've posted this. You were right, there was a marked difference! Regardless, the scope is still well corrected.

By "well designed and adjusted achromat" I was refering to the design of the lens cell. The lens shows no noticable defects is alignment and is as well corrected for abberations as any quality achro I've used. I know that is a rather subjective statement, but this is a first light report, not an optical bench analysis. ;)

The Stellarvue All Stars is a brand specific club that Vic started earlier this year. In addition to the newsletters, we get advance word on new products and special offers from "the mother ship". Info on the All Stars is on the Stelarvue web page. You don't have to be the owner of a Stellarvue scope to be a member, nor do you have to be a member to buy from Stellarvue. BTW - The Stellarvue F50 finder scope is EXCELLENT!

I did resolve my focuser issue with the 102 f/11. As it turned out, the slow speed shaft was not machined smoothly which made the feel focuser "bumpy". I turned it on my lathe with some very fine sandpaper to smooth out the lumps and it worked fine. Shortly after doing that, I adapted an Orion Electronic Focuser to the Crayford which made the whole issue moot as the slow speed assembly had to come off anyway. Oh well, it was fun to fix! :D

#21 Trever

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Posted 08 October 2009 - 03:40 PM

I hope to be able to use mine soon. I love the construction of the scope. It is a good match for my tall DM6.

Seems the trend nowadays is to produce scopes with no easy way to mount a finder so I purchased a Rigel quickfinder for this one and my A80EDTA. Both do not have a finder bracket but that is no big deal to me.

#22 Binojunky

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Posted 24 January 2013 - 05:29 PM

This scope is available from Canadian Telescopes,$500 with free shipping,DA.

#23 Lane

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Posted 24 January 2013 - 06:04 PM

These come with the Stellarvue Rack and Pinion focuser now and that is a really sweet focuser.

#24 Mike W

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Posted 24 January 2013 - 06:52 PM

50mm monting bracket for a Schmidt cass mounts right on the top of the ring w/ MINOR mods.

I hope to be able to use mine soon. I love the construction of the scope. It is a good match for my tall DM6.

Seems the trend nowadays is to produce scopes with no easy way to mount a finder so I purchased a Rigel quickfinder for this one and my A80EDTA. Both do not have a finder bracket but that is no big deal to me.

Attached Thumbnails

  • 5641252-IMG_0925.JPG


#25 Mike W

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Posted 25 January 2013 - 06:42 PM

Here's a photo with finder attached

50mm monting bracket for a Schmidt cass mounts right on the top of the ring w/ MINOR mods.

I hope to be able to use mine soon. I love the construction of the scope. It is a good match for my tall DM6.

Seems the trend nowadays is to produce scopes with no easy way to mount a finder so I purchased a Rigel quickfinder for this one and my A80EDTA. Both do not have a finder bracket but that is no big deal to me.

Attached Thumbnails

  • 5643132-IMG_0927.JPG



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