14 replies to this topic

[blackgalactic]

This is my first time (technically second) ever posting on CloudyNights forums. So, hello everybody!

I need advice. Recently, I saw an ad go up for a Celestron C8 orange tube, supposedly vintage (that's what I've heard, at least) and it's going for around 450 dollars, tripod included. As someone who owns a telescope with a GEM mount (my first telescope is an Orion Starblast ii 4.5 in.) I don't know what to do because it's a fork mount!! While I have nothing against fork mounts, I'm a bit scared to get it because I don't know anything about them and I am wanting to start astrophotography sometime in the future, and I heard fork mounts aren't good for that! I heard of de-forking before, but I'm not sure if this specific model is capable of it?

If there's any tips I could get, it would be really appreciated. Thank you [:

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[mpsteidle]

If your end-goal is astrophotography, I wouldn't purchase this.  THAT SAID, this is an excellent example of a vintage C8, with what looks like very clean paint and the original very sturdy tripod.  $450 is a fine price for what looks to be a very clean instrument which will give some nice views.

[lee14]

Fork mounted SCT's are perfectly capable of high quality astrophotography, as is consistently confirmed by the plethora of fine images right here on CN. However...this scope will need some additions to facilitate anything beyond the most basic short exposure pics. First, it appears to lack a declination motor, making any sort of guiding a non-starter. These were an add-on, they were not supplied with the basic scope. Additionally, a hand controller is required to enable manual guiding. It's a very nice scope, a true classic, but to set it up for astrophotography is going to take some doing. And cash.

 

Lee

[lee14]

Yes, it can successfully be de-forked, but it's probably a bit much for your Orion GEM. In any case, you'd have to add a dovetail plate to the lower portion of the tube. The good news is that the the tube already has predrilled and tapped holes for a standard [like losmandy] rail.

 

Lee

[shooze]

I'd buy that in a heart beat for $450.00

[blackgalactic]

Fork mounted SCT's are perfectly capable of high quality astrophotography, as is consistently confirmed by the plethora of fine images right here on CN. However...this scope will need some additions to facilitate anything beyond the most basic short exposure pics. First, it appears to lack a declination motor, making any sort of guiding a non-starter. These were an add-on, they were not supplied with the basic scope. Additionally, a hand controller is required to enable manual guiding. It's a very nice scope, a true classic, but to set it up for astrophotography is going to take some doing. And cash.

 

Lee

This might be a bit of a dumb question, but just to make sure, what exactly is a hand controller? Are you talking about the hand knobs similar to those on manual GEMs? Could you perhaps also link some examples that would work with this scope too? Thanks!   

[lee14]

This might be a bit of a dumb question, but just to make sure, what exactly is a hand controller? Are you talking about the hand knobs similar to those on manual GEMs? Could you perhaps also link some examples that would work with this scope too? Thanks!   

It's a perfectly reasonable question. A hand controller operates the two motors electronically, by activating buttons contained in a small box that is connected to the mount by a cable. The primary use in a scope like this one is to enable small corrections necessary during manual guiding. The scope as pictured will run without one, the Right Ascension drive is integral to the base and should operate when the cord is plugged in and switched on. Modern controllers are more complicated, they'll access the 'GOTO' functions, perhaps display object coordinates, etc.

 

Again, a hand controller isn't necessary to operate this scope, both axes can be moved manually, similarly to the knobs on your GEM. 

 

The pic here is basically what was used on a C8, whether or not they're still available new, I'm uncertain. 

 

Lee

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[davidmcgo]

The hand controllers were for the later Powerstars and Celestars.  What you would use to guide a AC drive like the scope posted is a drive corrector which took 12v DC and created a variable frequency AC from it so the motor could be sped up or slowed down.

 

And with highly sensitive digital cameras, you can get decent result without that since the individual exposures are around 30 seconds or so.  Just discard the ones where the drive gears jump.

 

Dave

[Tenacious]

If your end-goal is astrophotography, I wouldn't purchase this.  THAT SAID, this is an excellent example of a vintage C8, with what looks like very clean paint and the original very sturdy tripod.  $450 is a fine price for what looks to be a very clean instrument which will give some nice views.

+1. 

 

I wonder how many C8s on their original mounts are left.

[1Al]

These vintage Celestron are so beautiful

[Isaac M.]

This is an example of a drive corrector for the c8, it can allow you to change the speed of the mount and you can use it to make sure your target is centered. These are a bit hard to come by though.

 

Isaac

[RichA]

This is my first time (technically second) ever posting on CloudyNights forums. So, hello everybody!

I need advice. Recently, I saw an ad go up for a Celestron C8 orange tube, supposedly vintage (that's what I've heard, at least) and it's going for around 450 dollars, tripod included. As someone who owns a telescope with a GEM mount (my first telescope is an Orion Starblast ii 4.5 in.) I don't know what to do because it's a fork mount!! While I have nothing against fork mounts, I'm a bit scared to get it because I don't know anything about them and I am wanting to start astrophotography sometime in the future, and I heard fork mounts aren't good for that! I heard of de-forking before, but I'm not sure if this specific model is capable of it?

If there's any tips I could get, it would be really appreciated. Thank you [:

1978

[Paul Sweeney]

Buy it. It is a great visual scope.

For photography you need a camera and a computer. Motors help, buy are not absolutely necessary. My friend took a photo of the Horsehead nebula with a Canon camera on a standard 8" dob.

The fork mount used to be an issue when cameras used film and exposures were long. Stars would turn to streaks because the fork couldn't track properly. This scope has a wedge, which eliminates the problem.

With a modern camera, you take a bunch of short exposures and stack them. There is software that does this automatically.

Before investing in astrophotography, find your local club. There will be people there who will help you avoid a lot of pitfalls and save you a lot of frustration.

Edited by Paul Sweeney, 01 November 2024 - 03:56 PM.

[Artanoon]

 

This is an example of a drive corrector for the c8, it can allow you to change the speed of the mount and you can use it to make sure your target is centered. These are a bit hard to come by though.

 

Isaac

 

I used this C8 when I was a lad (first year physics student in 2000), in Iran. It is a good scope and I took several good moon and sun photos with it with my Minolta film camera.

 

Back then, my professor told me that he used a "drive controller" with this C8 when he taught astronomy in the US in the 80s I never used one of these controllers. Of course later the uni bought some more modern Meade and Vixen scopes with two axis motorised mounts, so I missed the opportunity to learn about these analogue drive controllers.

 

Being a kind of guy who still listens to audio cassettes and taking photos with film, I am now thinking to buy one of these vintage C8s - one is available locally in the UK. I am planning to build a controller for it. Does the controller work based on changing the frequency of the AC you think? I could build a circuit that changes the frequency of the AC and then upscale it to 220V assuming that is the voltage with which the motor works? for forward or backward perhaps >50Hz and <50Hz temporarily and for Moon or sun tracking adding a permanent offset to the 50Hz using a knob (or digitally, using Arduino or something). Not sure if any of my nonsense makes sense?  

 

Appreciate having your thoughts

Arta

[Orion68]

Looks like one I bought on Ebay back in the early 2000's. I still have the OTA and it has excellent optics. Took me forever to learn to collimate it.

 

A well collimated C8 can give superb views. You did well. This is mine...