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Some questions about a Celestar 8(?)

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#1 saitch

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Posted 04 August 2020 - 11:20 PM

I have a few questions about a scope I just purchased, if any of you good people would be willing to help a beginner out here.  My first scope was a 4se so the mount etc. are all pretty unfamiliar to me.  My first question is what are the following handles for?  Are they just for moving the tripod?

 

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My second question is about the slow motion control knob on the R.A. axis.  Mine is not attached...is glue a reasonable way to get it back on or is there a better method?
 
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Finally, I was trying to check the collimation via a guide I found.  When doing so I noticed that part of the secondary is obscured by what appears to be part of a gasket or something that has squished into its baffle...whatever it is, it's ribbony and shiny.  It appears from about 5:00 to 9:00 on the secondary below.
 
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You can also see a bit of haze on the mirror close to it.  What is it likely to be?  How much will it affect the scope optically, and can it be reasonably fixed?  Thanks very much for any information you can give!

 



#2 Thomas Marshall

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Posted 05 August 2020 - 01:10 AM

I don't have that scope mount, but concerning the knob you want to glue, - you can see the set screw in your pic, - just slip it on and tighten with allen wrench.  I hope 1 out of 3 ain't bad.?     The shaft probably has a flat side, - tighten the set screw on that. 


Edited by Thomas Marshall, 05 August 2020 - 01:17 AM.

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#3 saitch

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Posted 05 August 2020 - 01:26 AM

you can see the set screw in your pic, - just slip it on and tighten with allen wrench.

Thanks Thomas, I don't know why I didn't realize that it was a screw!  I feel a little silly for asking that one now haha  Much appreciated.


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#4 Redbetter

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Posted 05 August 2020 - 01:33 AM

Back the grub screw out a little before you try to put it on the shaft, just to make sure it doesn't prevent the knob from seating down properly on the shaft.  Then tighten the grub screw.  

 

I don't have any experience with the deluxe version of the equatorial mount.

 

The haze you mention is a concern.  It looks like it is on the secondary and in a line which could mean that it had condensation pooling there at some point in storage.  Might just be cosmetic, or it could be damage to the coatings of the secondary.  I don't know how much it will impact the image.


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#5 davidmcgo

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Posted 05 August 2020 - 07:48 AM

The handles on the wedge allow for azimuth adjustment of the wedge when the 3 screws on the top plate are a bit loose.  Something for casual use you don’t really need to worry about.

 

Regards the secondary, can’t tell from the picture if it is a blob of grease that dropped off the baffle tube and collected there or not.  There should not be any gasket material that could get there.

 

google for one of the sites on removal of the corrector and try to clean it with dish liquid and warm water.  Normally I would suggest acetone but the baffle is plastic  and they used a double sided adhesive to attach the small mirror to its aluminum backing plate.

 

Dave


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#6 saitch

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Posted 05 August 2020 - 11:42 PM

Thanks for the information Dave and Redbetter!



#7 saitch

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Posted 07 August 2020 - 11:23 AM

Well, I removed the corrector to see exactly what was going on in there and it turns out that the plastic on the secondary holder next to the mirror had melted somehow.  Maybe someone was looking at the sun for too long?  Anyway, thanks again for the help, guess I'm off to see if I can find an old secondary holder somewhere.

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#8 Redbetter

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Posted 07 August 2020 - 06:11 PM

Wow!   It does make you wonder if someone had a near solar accident.  Maybe a scope left out, cap got knocked off, solar filter knocked askew, etc.  Might have even been some sort of daylight inspection or cleaning accident by the original owner when they weren't paying careful attention to Sun angles, or even a reflection from elsewhere into the uncapped OTA.  




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