I have an old C90 or similar Celestron spotting/astronomical scope. The focus with the big ring is very sticky and stiff. How can I fix this?

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	I have an old C90 or similar Celestron spotting/astronomical scope. The focus with the big ring is very sticky and stiff. How can I fix this?

Answer Your vintage C90 needs the damping grease replaced.

You can do this yourself. Carefully remove the tripod adapter foot (for spotters) to find a screw or pair of screws that when removed that will let you unscrew the front end of the optics of your Maksutov. Use care to remove the old grease with a lint-free cloth. Caution is needed so as not to contaminate the optics. You may need to dig out old caked deposits with a toothpick. Replace the grease with a quality high-temperature grease (such as Mobil One Premium). Sparingly place a few dots of the new grease at 2-4 places on the treads and work the threads back and forth to evenly distribute the new lubricant. Wipe off any excess. Replace the screw(s) that limit the front optics motion.

If you don’t want to do this yourself, contact Celestron factory service.

Article Details

Article ID:

2126

Created On:

Nov 26 2008 11:13 AM