WO ZS81 Handlebar Sliding Overnight William Optics ZenithStar 81 / ZS81 · Martin Hébert · ... · 7 · 276 · 0

Martin1415 0.00
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Hello!

This morning, I went to take down my setup and I notice that the telescope was shorter than at the start of the night. I quickly realized that it slid from the handlebar sometime during the night, I checked to see if everything was tight and it was. I think my issue that the telescope is bottom heavy as I have a lot of attachments (angle rotator, ZWO focuser, Flat 3, ASI294MC, ASIAIR).

Did you ever encounter this? Do you have any suggestions on how to avoid the telescope from sliding?

Thanks,

Martin
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Siriusdwarf77 2.41
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Hmm, this is a tricky one. However, after reviewing all the options, I have come to the stunning conclusion that the best way to solve this problem, would be to make sure you tighten everything up correctly and with reasonable force before leaving the scope outside. It could not have been as tight as you thought. Hope this helps. K.
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JanHeremans 0.00
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Strange it was tight when you checked again after your session.
When I put my gear outside I tighten everything. I only start imaging after one or two hours to get the scope acclimatized.
Before the polar alignment I make sure I tighten everything again.
You could put some electrical tape on the sides of the dovetail, this might help.

CS,
Jan
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apo20232 0.00
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Martin,

A similar thing happened to me with my Zenithstar 81, but my issue was that I did not check prior to the session to see if the rings were tight. As I was imaging near the zenith, the OTA started to slide in the rings. I couldn't figure out why my guiding was steadily getting worse until I came outside and noticed the OTA had noticeably slipped through the rings to make my rig bottom heavy and out of balance. It could have been a disaster, but I learned to check everything for tightness before each session.

Jim
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apo20232 0.00
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Once other thought came to mind. As the OTA cooled down overnight could it have shrunk in diameter ever so slightly, but expanded as the temperature rose in the morning to create the illusion of a tight fit?

Just a random thought.

Jim
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Martin1415 0.00
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Those are some great ideas! Thanks everyone! Next time out I will make sure to tighten the scope a couple of hours after the rig is set-up.  I think it was related to the temperature (it was really cold in Canada that night, around -12).  Worst case scenario, I will try the tape.

CS

Martin
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ivanrmcc 3.31
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Martin, I have similar issues in very cold temperatures.  I have concluded that it is down to metal shrinking in below freezing temperatures.  In the summer time I don't have to worry about retightening everything during a session, but in Western Canadian winters everything seems to get loose as the night goes on (even my AM5 mount needs to be retightened to the tripod).  Hope this helps.
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ChuckNovice 6.42
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My WO FLT120 had this slipping problem in cold temperatures when pointing up to take flats. Didn't bother to find the right material to add to the rings and instead opted to apply a single strip of 3M adhesive velcro under the tube just in front of the ring to block it. 8 months later and I haven't had this problem ever again. You don't need a lot of force to hold it in place as it's barely slipping, just a little something to block it.
Edited ...
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