Mounting an old C8

[Tenor Viol]

I am currently waiting for a nice shiny 100mm refractor to arrive... to put on my new HEQ5 PRO. 

Meanwhile, lurking in the garage in a case that hasn't been opened in over 20 years is a 40 years old this year Celestron C8 - the original fork mounted type in orange.... I'm suspecting that in order to get say a long dovetail plate to fit to it will require some modifications? At 2,000mm f/10 it will be good for lunar and Jupiter and Saturn. 

Has anyone any experience of doing this with the old style C8? It's fair to say I either lack the requisite skills or equipment to do anything more complex than screw/bolt things together, is if it is more than that, suggestions as to who could carry out any necessary modifications would be welcome. I realise DEC balance will be an issue on a GEM with an SCT...

(In case you're wondering... back in 1980 when I bought it, there were no such things as dew straps, or much of anything else and I just found it not easy to use, eyepieces were ferociously expensive and I was a lowly bank clerk at the time, then I bought a house....).

Ron. 

 

[Laurin Dave]

Take a look at these Ron..  https://www.firstlightoptics.com/adm-losmandy-type-d-series/adm-losmandy-dovetail-for-optical-tubes.html  there's one for a Celestron 8", FLO should be able to be able to find out if it's the correct one  ..  If its similar to my Meade then just a few allen screws to undo (which no doubt will be imperial) to take it off the forks then remove four of the screws that hold the mirror and corrector plate assemblies on and screw the dovetail on using use the same holes and new screws (which should be supplied)..   

HTH 

Dave

[RT65CB-SWL]

I have just been looking at that page too!

[johninderby]

According to Celestron you just need a dovetail bar.

https://www.celestron.com/blogs/knowledgebase/i-have-an-old-fork-mounted-celestron-schmidt-cassegrain-telescope-sct-can-i-convert-this-to-a-goto-mount

[Tenor Viol]

21 minutes ago, Laurin Dave said:

Take a look at these Ron..  https://www.firstlightoptics.com/adm-losmandy-type-d-series/adm-losmandy-dovetail-for-optical-tubes.html  there's one for a Celestron 8", FLO should be able to be able to find out if it's the correct one  ..  If its similar to my Meade then just a few allen screws to undo (which no doubt will be imperial) to take it off the forks then remove four of the screws that hold the mirror and corrector plate assemblies on and screw the dovetail on using use the same holes and new screws (which should be supplied)..   

HTH 

Dave

Dave - thanks for that. I will ask FLO as it looks like it's exactly what is needed. 

[Cosmic Geoff]

The later C8's have dedicated dome-headed screws front and back for fixing dovetail bars, finders, etc.  With luck, the old ones will have similar.  The hardest part of using them is figuring out the thread sizes so you can buy bolts of the right length - probably UNF or UNC in this case.

What are you going to mount it on - the HEQ5 Pro?

[Tenor Viol]

58 minutes ago, Cosmic Geoff said:

The later C8's have dedicated dome-headed screws front and back for fixing dovetail bars, finders, etc.  With luck, the old ones will have similar.  The hardest part of using them is figuring out the thread sizes so you can buy bolts of the right length - probably UNF or UNC in this case.

What are you going to mount it on - the HEQ5 Pro?

Hi - yes, the plan was to put it on the HEQ5. I'll dig it out of the garage tomorrow and have a look. It's been locked in its case, so hopefully the optics are all OK. I suspect when the fork mount and motor base is removed, the OTA is not too heavy. 

[Tenor Viol]

Following an e-mail chat with FLO, going for the dovetail bar... so in a week or two I should be able to get the C8 out of its box for the first time since somewhen in the 1990s....

[jonathan]

If nothing else works, surely a pair of 200mm tube rings would do the trick?

[Tenor Viol]

Ok. Went for a bit of kit from ADM bought from FLO. It as an easy thing to swap over. Get case out of the garage where it has been untouched for 20+ years. Four screws to remove fork mount and motor base. Bolt on shaped piece then attach Vixen dovetail, bolt on the other piece and bolt other end of dovetail. Sorted. 

 

Have a ferret for box of telescope bits which have not been seen since I moved to current house 21 years ago... I find the Pentax K mount adaptor... and after some further digging find the Nikon F mount one. Need to do some research as the C mount just seems to be 'Japanese inch' which seems a little small... 

 

[Tenor Viol]

PS - thank you to everyone for their assistance in helping me to resolve this. 💫

[PaulSR]

Hi Ron - just wondering how easy the job turned out to be. You make it look/sound really simple - did you find the holes in the tube corresponded to holes available on the dovetail bar, and did you use screws supplied with the bar? 

I have the same model C8, and have just purchased a second hand HEQ5. 

Thanks! 

Paul