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"The JMST" — a quest to restore a 1974 C8 by a telescope newbie

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#1 CartoonOwl

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Posted 07 December 2020 - 01:46 PM

Some of you guys may have seen my post to the C8 registry thread, but I was encouraged to post a new thread to tell you guys about what I've got and ask ALL THE QUESTIONS about what I need.

 

Let me introduce you to the John Mayer Sky Telescope, so named after the friend who left it to me, and as a wink to the James Webb Space Telescope, a project of which I also have a personal connection (a story for another time):

 

I have no idea what this is
the tube
secondary mirror
forks
the plate
The back end of the scope, view 2
The back end of the scope, view 1
 
So, this is not my first restoration rodeo, but it is my first telescope. I am doing a lot of reading right now, and slowly and carefully cleaning the dirt and grime off the outside of the scope (I'm not touching anything glass yet. I have supplies around to clean my camera equipment, but I want to de-gunk as much as I can before I start on the actual optical parts of the scope. Not that the optics seem to need much- he kept it covered, and there are a few specks of dust that need to be brushed away, and little else). Some helpful folks suggested that the weird wiring situation around the corrector plate housing was a DIY dew heater, and based on what I know about my friend John, this seems terribly likely. All the same, I'm going to endeavor to remove all of the tape residue and hot glue.
 
I do not have any accessories, no eyepiece, and no tripod. What you see here is all I've got; in my reading I'm thinking I'm going to need a visual back (unless the threading *is* the visual back? I'm not sure), a diagonal and some eyepieces, but I am new to this world and I'm not sure specifically what is compatible with this model (Q3 1974- in my reading I'm getting the impression that modern fittings aren't compatible? Is that true?)
 
Can you guys help me on my quest? What part numbers am I looking for? What do I need? What can I use that's being made now? What questions should I be asking? Am I crazy for imagining I might be ready to be able to haul this beast out to look at the Conjunction this month?

Edited by CartoonOwl, 07 December 2020 - 01:51 PM.


#2 Defenderslideguitar

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Posted 07 December 2020 - 02:07 PM

Hello welcome aboard and you have come to the right place

Folks more experienced than I will chime on what to do  and I benefitted from their advice on what not to do..

 

You will need a screw on visual back diagonal eyepiece holder. I still have my 1979 C-8  but my 1973 Sandcast model did well with a couple of screw on VB diagonals    I have two of the Celestron 2 inch VB's which have the adapter for 1.25 eyepieces which for me was the best of both worlds..

Eyepieces..   I have had good luck with good inexpensive used ones right here in the classifieds

 

Good luck and keep looking up


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#3 JosephATL

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Posted 07 December 2020 - 02:08 PM

Bare minimum, you need a visual back and an eyepiece.  A mirror diagonal will allow you to look at your targets without having to contort your body to weird angle, so it is very high up on the list.

 

Before the conjunction, take it out and get used to using it.  Make sure your finder scope is aligned.

 

Part of a tune up with these scopes is a process call collimation.  In short, it aligns the two mirrors inside your telescope by adjusting the three bolts in the front-center of the objective.  There are a number of how-to articles on this forum and elswere on the internet.  My best tip is to use a fold-out multi-tool like this one to turn the hex bolts at the front of the scope.  I keep this one in my bag and it has saved me a number of times.

 

https://www.parktool...ompatible Tools

 

PS, I also have one of these old C8 "orange tubes" as they are called.


Edited by JosephATL, 07 December 2020 - 02:09 PM.

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#4 ccwemyss

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Posted 07 December 2020 - 03:52 PM

The holes in the fork arms indicate that this is one of the earlier "sand cast" models. The later "die cast" ones lack those holes. Generally, people here feel that the sand cast C8s were better, in part because Celestron's quality control went downhill during the Halley's Comet craze. Others will note that Celestron's quality varied somewhat even with the earlier ones. But there seems to be a better chance of good quality with this vintage. It's well worth the effort to restore. Other than the modifications, it looks like it was kept in excellent condition. 

 

Chip W. 


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#5 Kasmos

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Posted 07 December 2020 - 04:40 PM

Here's a age appropriate instruction manual and for starters it should show and explain most everything

 

http://www.company7....8manual1971.pdf

 

and here's one for slightly newer models. It's pretty much the same but you might cross reference the two

 

https://wiki.telesco...ting_Manual.pdf

 

 


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#6 CartoonOwl

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Posted 07 December 2020 - 05:07 PM

Here's a age appropriate instruction manual and for starters it should show and explain most everything

 

http://www.company7....8manual1971.pdf

 

and here's one for slightly newer models. It's pretty much the same but you might cross reference the two

 

https://wiki.telesco...ting_Manual.pdf

Thank you for the manual link! I think I saw you post this in another thread (your name looks familiar- I have been lurking for a few days). So I have that downloaded to my iPad already.

 

 

Bare minimum, you need a visual back and an eyepiece.  A mirror diagonal will allow you to look at your targets without having to contort your body to weird angle, so it is very high up on the list.

 

Before the conjunction, take it out and get used to using it.  Make sure your finder scope is aligned.

 

Part of a tune up with these scopes is a process call collimation.  In short, it aligns the two mirrors inside your telescope by adjusting the three bolts in the front-center of the objective.  There are a number of how-to articles on this forum and elswere on the internet.  My best tip is to use a fold-out multi-tool like this one to turn the hex bolts at the front of the scope.  I keep this one in my bag and it has saved me a number of times.

 

https://www.parktool...ompatible Tools

 

PS, I also have one of these old C8 "orange tubes" as they are called.

Oh THIS, about the hex wrenches is something I knew I needed to ask but kept forgetting to! Thanks. I have dozens of allen wrenches and hex drivers for projects and not a single one fits any of the screws here! 

 

Before I do collimation, I still need to take the tube off the fork to really get in there and detail clean it before I start just grinding all this dirt and grit into the works playing with it. 

 

This is part of why I'm like "is it nuts for me to think I'll be able to have this in working shape before the 21st?" There's a lot to do yet, just giving it some love, calibrating the spotting scope, figuring out how it all goes together without doing damage to it. I'm more determined to do it right than fast. 


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#7 B 26354

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Posted 08 December 2020 - 03:38 AM

and here's one for slightly newer models. It's pretty much the same but you might cross reference the two

 

https://wiki.telesco...ting_Manual.pdf

Thank you so much for posting this. I still have my own original copy, but I've never been able to locate a PDF of it. waytogo.gif


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#8 AlessiR

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Posted 15 December 2020 - 06:50 PM

Thank you so much for posting this. I still have my own original copy, but I've never been able to locate a PDF of it. waytogo.gif

Is this what you’re referring to? Tried to post here, but 500kb limit....

 

https://stargazerslo...ad-for-manuals/



#9 B 26354

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Posted 15 December 2020 - 08:52 PM

No... but thanks anyway!  waytogo.gif

 

The one I've never been able to find online, is the one that Kasmos provided the link for.  grin.gif



#10 AlessiR

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Posted 19 December 2020 - 02:01 AM

This looks fantastic!  I recently found an old orange tube c5 at a thrift store.... I was curious about this coating and how to properly clean the exterior.. I’m not quite sure of what this original finish is, and as I’ve taken firm nylon brushes to it, I haven’t been able to get the strange buildup off but have been afraid to go the more abrasive rout.. any assistance would be greatly appreciated! Thanks 

 

Rick 


Edited by AlessiR, 19 December 2020 - 02:02 AM.


#11 B 26354

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Posted 19 December 2020 - 02:39 AM

I recently found an old orange tube c5 at a thrift store.... I was curious about this coating and how to properly clean the exterior.

Never use anything "firm" to clean an optical surface. Search this website and read everything you can find. Post a thread of your own in the "Cats and Casses" forum, titled something like "How do I clean my C5's corrector-plate?"

 

grin.gif



#12 AlessiR

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Posted 19 December 2020 - 08:36 AM

Never use anything "firm" to clean an optical surface. Search this website and read everything you can find. Post a thread of your own in the "Cats and Casses" forum, titled something like "How do I clean my C5's corrector-plate?"

No way would I! You misunderstood, sorry... I was referring to the outside/exterior of the tube and fork mount/base...


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#13 CartoonOwl

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Posted 22 December 2020 - 06:26 PM

Update on my first three days out with the JMST:

 

Thanks to some very kind assistance by a few C-N members, I got all of of the bits and pieces I needed to catch the conjunction and show my mom and my covid-pod. Also got a pretty killer view of the moon, and then Mars, just for funsies. 

 

Right now, since I had a bit of a deadline, I've been using the "swing it around and swear a lot" method of finding objects in the sky. Figured out how to align the spotting scope and the main scope on the first night; haven't tried to collimate the mirrors yet because the focus was good enough with a 40mm lens, but it might need more work now that I have more time. 

 

It's a learning process!

 

AlessiR, I took a damp rag to the exterior of mine, after years in storage made the orange body look brown. I wiped everything down while all of the optics were covered. That might be enough. As for the paint, it looks like a matte enamel to me. There a few scratches that I may or may not eventually fill, but right now I kind of think it gives it character. I haven't gone looking to see if there's a Pantone number associated with Celestron's orange yet, but I'd bet a dollar there is.


Edited by CartoonOwl, 22 December 2020 - 06:27 PM.

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#14 CartoonOwl

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Posted 03 January 2021 - 04:01 PM

Welp, the word on the street is that the power cable for this beast is nigh-impossible to find; I'm going to have to make one. I do not like soldering wires, mostly because I'm sure I'm going to end up doing something wrong and electrocuting myself. I can see the obituary now: "She died as she lived; in the middle of a half-dozen mad projects, frizzy-haired from either the shock or the humidity."

 

In the meantime, I don't mind following objects around by hand using the fine controls while I'm mostly alone. It's just a bit awkward if I'm showing things off to people, having to butt in and adjust the view every 30 seconds. I don't even know if the clock motor even works, but there's only one way to find out. 



#15 B 26354

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Posted 03 January 2021 - 07:30 PM

Might not need to solder anything. If you can find the correct plug, it'll be a simple connection. Finding the plug is the problem. A person on eBay is selling chords that he/she made. and the photos show the plug.

 

https://www.ebay.com...SQAAOSwIFBf1VL-

 

https://www.ebay.com...M0AAOSwzttdv6OG

 

They look an awful lot like these:

 

https://www.ebay.com...5.c101196.m2219

 

Anyone out there able to verify??

 

grin.gif



#16 davidmcgo

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Posted 03 January 2021 - 08:04 PM

That is it but you will need to strip the ends of both leads and solder to the connectors that go inside that housing.  Pretty easy to do on lamp cord gage wire, not anything hard like surface mount stuff.  And the motors go off the phase so polarity does not matter. Give it a go.

 

Dave


Edited by davidmcgo, 03 January 2021 - 08:05 PM.

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#17 CartoonOwl

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Posted 03 January 2021 - 09:24 PM

Might not need to solder anything. If you can find the correct plug, it'll be a simple connection. Finding the plug is the problem. A person on eBay is selling chords that he/she made. and the photos show the plug.

 

https://www.ebay.com...SQAAOSwIFBf1VL-

 

https://www.ebay.com...M0AAOSwzttdv6OG

 

They look an awful lot like these:

 

https://www.ebay.com...5.c101196.m2219

 

Anyone out there able to verify??

 

grin.gif

I did some deep reading here on the forum and got confirmation that that's the plug I'm looking for. It's on its way already (thanks ebay!). Those pictures of the homespun cords that that guy is selling on ebay are basically what I'd be able to do myself (I made a lamp as a Girl Scout but it's been...a while since then, hence the trepidation. The thing about having a lot of hobbies is that one successful attempt twenty-cough-cough years ago does not make for a confident expert). Fingers crossed!


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#18 RSX11M+

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Posted 12 February 2021 - 12:58 PM

Sorry I haven't looked for this thread until now. You seem to be getting all the help you can use.

 

I'm wondering about the present JMST project status -

 

  • Did the power chord work? (eg - did it plug in without releasing any magic blue smoke?)
  • Do the motors work? Were they noisy?
  • How's the "feel" as the base is moved manually in RA? (Smooth and free, slow and stiff... etc)
  • Did you inherit any tools or other bits with it? (bolts, screws, whatnot)

 

Let us know what we can help with. 

 

Your image gallery helps alot.



#19 RichA

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Posted 16 February 2021 - 12:55 PM

 

Some of you guys may have seen my post to the C8 registry thread, but I was encouraged to post a new thread to tell you guys about what I've got and ask ALL THE QUESTIONS about what I need.

 

Let me introduce you to the John Mayer Sky Telescope, so named after the friend who left it to me, and as a wink to the James Webb Space Telescope, a project of which I also have a personal connection (a story for another time):

 

 
 
So, this is not my first restoration rodeo, but it is my first telescope. I am doing a lot of reading right now, and slowly and carefully cleaning the dirt and grime off the outside of the scope (I'm not touching anything glass yet. I have supplies around to clean my camera equipment, but I want to de-gunk as much as I can before I start on the actual optical parts of the scope. Not that the optics seem to need much- he kept it covered, and there are a few specks of dust that need to be brushed away, and little else). Some helpful folks suggested that the weird wiring situation around the corrector plate housing was a DIY dew heater, and based on what I know about my friend John, this seems terribly likely. All the same, I'm going to endeavor to remove all of the tape residue and hot glue.
 
I do not have any accessories, no eyepiece, and no tripod. What you see here is all I've got; in my reading I'm thinking I'm going to need a visual back (unless the threading *is* the visual back? I'm not sure), a diagonal and some eyepieces, but I am new to this world and I'm not sure specifically what is compatible with this model (Q3 1974- in my reading I'm getting the impression that modern fittings aren't compatible? Is that true?)
 
Can you guys help me on my quest? What part numbers am I looking for? What do I need? What can I use that's being made now? What questions should I be asking? Am I crazy for imagining I might be ready to be able to haul this beast out to look at the Conjunction this month?

 

Kendrick should use that first image in his ads for dew heaters.  "What not to do to your scope!"  Though when that was done to the C8, nothing commercial was out there.


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#20 RSX11M+

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Posted 16 February 2021 - 01:35 PM

Kendrick should use that first image in his ads for dew heaters.  "What not to do to your scope!"  Though when that was done to the C8, nothing commercial was out there.

I bet it looked just fine for the first 20 years or so. 45+ years on - none of us look the same without our covering.



#21 Kasmos

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Posted 16 February 2021 - 10:37 PM

Might not need to solder anything. If you can find the correct plug, it'll be a simple connection. Finding the plug is the problem. A person on eBay is selling chords that he/she made. and the photos show the plug.

 

https://www.ebay.com...SQAAOSwIFBf1VL-

 

https://www.ebay.com...M0AAOSwzttdv6OG

 

They look an awful lot like these:

 

https://www.ebay.com...5.c101196.m2219

 

Anyone out there able to verify??

 

grin.gif

Who would pay $61-$65 for a $3 extension cord attached to a $5-$10 plug?



#22 B 26354

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Posted 17 February 2021 - 12:48 AM

Who would pay $61-$65 for a $3 extension cord attached to a $5-$10 plug?

Which, of course, is why I put the third link in my post. grin.gif



#23 CartoonOwl

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Posted 17 February 2021 - 01:09 PM

Sorry I haven't looked for this thread until now. You seem to be getting all the help you can use.

 

I'm wondering about the present JMST project status -

 

  • Did the power chord work? (eg - did it plug in without releasing any magic blue smoke?)
  • Do the motors work? Were they noisy?
  • How's the "feel" as the base is moved manually in RA? (Smooth and free, slow and stiff... etc)
  • Did you inherit any tools or other bits with it? (bolts, screws, whatnot)

 

Let us know what we can help with. 

 

Your image gallery helps alot.

I haven't done it yet, but I have the parts. The holidays got busy and the new year left me a bit burnt out. I haven't abandoned the project, though! It's just going to take me a minute. These are great questions to think about as I see what happens the first time I plug it in.

 

There's another consideration- I live in an apartment building with no balcony and the courtyard is in the center of the 3-story complex. I have to take it out in my car to get any sky that isn't more-or-less straight up. How do you guys manage this situation? Is there some kind of car battery adapter I should also be acquiring or constructing?



#24 CartoonOwl

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Posted 17 February 2021 - 01:10 PM

Kendrick should use that first image in his ads for dew heaters.  "What not to do to your scope!"  Though when that was done to the C8, nothing commercial was out there.

It's ugly, to be sure lol.gif



#25 RSX11M+

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Posted 17 February 2021 - 01:30 PM

... I live in an apartment building with no balcony and the courtyard is in the center of the 3-story complex. I have to take it out in my car to get any sky that isn't more-or-less straight up. How do you guys manage this situation? Is there some kind of car battery adapter I should also be acquiring or constructing?

Responding to this in a meaningful way requires me to know, or assume, where you live on the planet - generally.

 

I'll take a stab at "North America" or USA.

 

In this locality, the most important view for astronomy purposes is Polaris (North Star), and an unobstructed view South.

 

All the Planets appear in an east-to-west arc across the sky to the South.

 

A view straight up, while useful, is not as important. Is this a small courtyard? Can you get a Polaris view at all by moving to one end or the other? What about the South?

 

Lets see if your equipment works before we get into all that deeply. - But it is coming.

 

Update:

 

Do you have a small computer UPS handy? I've been meaning to try one out with my Sand cast C8 - maybe I'll do that for giggles.


Edited by RSX11M+, 17 February 2021 - 01:40 PM.



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