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Celestar C8 and the Celestron 8" CGE dovetail

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#1 Electronchuck

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Posted 22 February 2021 - 05:37 PM

Looking to upgrade the mount for a circa 1999-2000 Celestar C8 OTA.  Does anyone know if the current Celestron dovetail fits the hole pattern?  Mirror-end holes are approx. 1.75" apart and the corrector-end hole is exactly 12.25" from those.



#2 jgillis99

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Posted 22 February 2021 - 06:06 PM

Hi electronchuck, I have a celestar 8 (circa 2001) with the original wedgepod. However, I threw the original tripod legs away, and attached the wedge to a much taller and beefier tripod so that I would no longer be sitting on the ground/crouched down to look at anything at altitude 60 deg or higher.

 

I'm confused by your question because the optical tube assembly (OTA)  for the celestar 8 has no "holes." Rather, it has side rails that attach to a fork mount that also includes the clock drive. You typically keep the OTA and fork mount attached as an assembly, and you attach / detach the assembly to/from the wedge.

 

I also responded because it is good to be able to contact another celestar 8 owner. I want to make the most of the equipment I have.

 

Best

 

John Gillis

Arlington, MA



#3 B 26354

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Posted 22 February 2021 - 07:24 PM

High Point Scientific carries many different types of these dovetails. Call their tech support, and ask them to point out the correct one for your model of C8.



#4 jgillis99

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Posted 22 February 2021 - 08:35 PM

B_26354's answer was much more helpful than mine. In a similar vein, I also suggest that you go to farpointastro.com and search for "dovetail." This is the company that bought jim's mobile (jmi.com) a few years ago. 



#5 Electronchuck

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Posted 22 February 2021 - 10:15 PM

I want to get rid of the fork and mount it on a German eq mount. I should have said in the post that there are mounting screws on the upper and lower sides of the the tube. Those are where rails go if desired. Thats where the rails for the current production Celestrons that are on GEMs are mounted.

#6 Electronchuck

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Posted 22 February 2021 - 10:18 PM

Also replying to John Gillis, have you ever done any lubrication of the fork drive gears? Is there any maintenance that should be done after 20 years?

Thanks all for the earlier replies.

#7 jgillis99

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Posted 23 February 2021 - 11:40 AM

I suspect that the clock drive is factory sealed with strong grease. I've never opened the cover to look and have only used the manual controls. After 20 years, it most likely does need some lubricant. When the weather is a little better, I will power it up using the Celestron "power tank" lithium ion battery pack I just bought and let you know.

 

I just looked at the instruction manual. There is a maintenance section, but it says nothing about lubricating the clock drive.



#8 Electronchuck

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Posted 23 February 2021 - 03:07 PM

Thanks. Pls post anything you figure out.

#9 telesonic

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Posted 23 February 2021 - 06:36 PM

While I can't confirm this, I suspect that the mounting hole specs haven't changed much over the years. I believe I have seen the older Orange Tube through late 1980's / 1990's Black tubed C8 all using similar dovetails on here, so I would think it would work just fine.

 

Keep in mind that if you do de-fork your C8 - be very careful the length of screws that you use to attatch your dovetail bar!

Using too long of a screw can possibly hit / damage your primary mirror. This is easily seen by looking down the front of the tube. I'm sure most vendors provide the proper length screws for use, this also goes for adding finders / etc to your C8.

 

I have a Celestar C8 that I mounted on a EQ mount. On mine, I used the ADM dovetail bar with radius blocks  - seen here:

And yes, ADM is good quality stuff! It's a little pricier than most, but well worth it. (not affiliated - BTW)

 

C8 pier test

 

(I used the V-series first, but later went with the wider Losmandy D-series on mine when I upgraded the saddle on my ASGT)

 

 

Best of luck,

And yes, the Celestars are darn good scopes - optically!

 

T



#10 Electronchuck

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Posted 23 February 2021 - 07:49 PM

Thanks very much. Yes, Highpoint had recommended that dovetail. Thinking of getting an AVX mount later in the year to start astrophotography. Your pic looks great. I agree that the Celestar is a great tube.

#11 telesonic

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Posted 23 February 2021 - 09:28 PM

Thanks very much. Yes, Highpoint had recommended that dovetail. Thinking of getting an AVX mount later in the year to start astrophotography. Your pic looks great. I agree that the Celestar is a great tube.

No problem! I used the Celestar on it's standard fork and Wedgepod for some time.... then it went through a series of upgrades over a few years. The mount pictured on my pier there is an older Vixen Super Polaris.... good mount, not very good when you start hanging a bunch of extra weight on it. Still love it for other scopes though.

 

The AVX will handle the C8 with plenty to spare for acessories - like 2" eyepieces, cameras - filter wheels, bigger finderscopes... etc. I believe it is similar in capacity to the CG-5 ASGT, which is it's older brother, with some updates. My ASGT handles the C8 with other stuff easily, and it was a nice upgrade that I don't regret one bit.

 

 

John / Electronchuck:

 

I've never dissasembled the Celestar drive base to check it's inner workings - so I really have no advice there, but I still have my drive base that I can check if needed.

By the way, there are two versions of the Celestar drive base - one is the "Basic Model" and the second one was named the "Deluxe" which had some different features / design improvements. 

 

 

Cheers,

T


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