Celestron Travel Scope 70 won't focus

[Matt888]

Hello,

I have owned a Celestron Travel Scope 70 for a few years, although I haven't used it much apart from going out to watch some events. Last month I went to see the eclipse and it worked fine as usual.... Just when the eclipse was at its apex I could not focus any more.  I don't know if I was nervous and moved the wheel too much in either direction because it was a very dark eclipse at its apex and I had lost the moon for a sec and fidgeted around with the wheels. I thought this was the case, but I was not able to focus it again.... not that night, and not when I went home.

I don't know what to do now. I tried to rotate the wheel all the way in both directions, but it won't focus any more. Any advice please? I know it is not a professional telescope, but it is really light and nice and I love it...

Thank you!

Matt

[Matt888]

I hadn't touched my scope since the eclipse because I was almost afraid to realize that it was really dead.

Today is the first day I looked at it and I have just noticed that for some unknown reason the big screw at the top (connected to the focusing wheels) was very tight, although I had not touched it, and that the wheels rotated, but the length of the scope didn't really change (I know this is not the right expression, but I guess you know what I mean, it did not go in and out and was stuck when rotating the wheels. I loosened it a bit and now I can focus! I am so relieved.   

[Knighty2112]

Did you project the image of the eclipse throught the scope onto paper, or did you use a solar filter? If the former it may have proved to hot for the focuser end which is mostly plastic I believe from memory on that scope, so may have warped the plastic possibly causing the problem perhaps with the focuser not been able to move because of this.

Edited June 22, 2021 by Knighty2112

[Knighty2112]

You should be able to unscrew the focuser end off the scope and check it internally for any damage if it was the heat of the sun causing the issue with the focuser.

[Matt888]

Thank you, I actually meant the moon eclipse...

[Knighty2112]

2 minutes ago, Matt888 said:

Thank you, I actually meant the moon eclipse...

OK. Well you can still take the focuser off and check to see what the issue may be. Its held in by just 3 screws. 

[Matt888]

I tried and it looks fine to me...

Is there something in particular I should look at to see if there is any damage? 

 

Edited June 22, 2021 by Matt888

[Knighty2112]

The rack and pinion area would be the place I would look at. The gear (the pinion part) that drives the pinion on the focuser out or in could have an issue causing the gear not to move, so if its held in the axle with a pin then check the pin is ok, and the gear part fits on the pin OK.

Check the gear under the cover in area 1. Should be similar on your scope I believe. Also when you have the gear and axle off the focuser you should be able to pull the focuser tube with the rack on to check as well to make sure no part has broken off it causing it not to move in the rack area 2.

Edited June 22, 2021 by Knighty2112

[Knighty2112]

Sorry the gear part is the pinion. 

[Matt888]

Thank you, I will have a better look. It seems to move now, but not really perfectly, so I will have a better look. Would a tiny drop of the kind of oil that is used for machinery or musical instruments be fine to ensure a smoother movement?

[Louis D]

2 hours ago, Matt888 said:

Thank you, I will have a better look. It seems to move now, but not really perfectly, so I will have a better look. Would a tiny drop of the kind of oil that is used for machinery or musical instruments be fine to ensure a smoother movement?

If you must, use a small amount of light grease on only the rack to help ensure it stays in place.  Wipe off any excess.  Oil tends to migrate everywhere.  You could also disassemble the pinion support and put a small amount on the axle inside and then reassemble it.

Edited June 23, 2021 by Louis D

[Matt888]

I will definitely try that, thank you.

[EntropyTango]

I recommend silicone grease for rack and pinion focusers

[Matt888]

It seems to be much better now...