Size of Philips screw driver for collimating a c11

[5ash (Philip)]

Hi can any one help tell me the best size Philips screw driver for collimating a celestron 11. I’m not interested in bobs knobs and am happy to stick with the Philips screws .
Regards philip

[astro744]

Likely Phillips #1 maybe #2. You could replace with socket head if not with Bob’s knobs. Some users report stripping the Phillips and prefer socket head screws but you will then have to match the thread, pitch and length. Not sure if it makes collimation any more or less sensitive.

Phillips #0, #1, #2, #3, #4, #5 are useful for many other applications. You can get shorter or longer handle versions. Note there are also Pozidriv that looks like Phillips. Search online for images and you’ll see the difference.

[JA]

Originally Posted by 5ash

Hi can any one help tell me the best size Philips screw driver for collimating a celestron 11. I’m not interested in bobs knobs and am happy to stick with the Philips screws .
Regards philip

Hi Philip,

If I had to guess, I would say that there's a 95% chance it would be a Phillips #2 screw head given that it's likely to be an M3 or M4 thread used for "regular" adjustment on a not too small object.

BTW, even though you don't want to change to a knurled thumbscrew, like a Bob's Knob, you could try using a socket head capscrew as a sort of half way house, as it would allow some hand adjustment like a thumbscrew as well as adjustment with a suitably sized Hex/Allen key for about 50 cents.

Best
JA

[Dennis]

This is a link to a Celestron webpage titled "What are the sizes of collimation screws on Current-production Celestron optical tubes"?

https://www.celestron.com/blogs/know...-optical-tubes

Cheers

Dennis