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Bob's Knobs?

northcanadian

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scarp15

scarp15

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I have fitted Bobs Knobs collimation screws to my 300mm reflector dobsonian and they are very easy to use, in this set up I would not be withour them. They do, in some ways, perhaps make even more sense with an SCT, as otherwise using a screwdriver, say in the dark, at such close proximity to the corrector plate is a bite nerve racking.

However I have not fitted them to my C8, as it seems to hold its collimation extremely well, even after travelling. Replacing the very firm stock screws with Bobs Knobs might mean that it may indeed require more collimation attention, due to the replacement bolts not being quite as locked in.

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faulksy

faulksy

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have thought about them for my sct but scared of loosing the colimation that i have now, whats worse is derek of here changed his and it took him ages to get it back in alignment, yes i am scared.any one know any good tutorials ?

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rowan46

rowan46

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have thought about them for my sct but scared of loosing the colimation that i have now, whats worse is derek of here changed his and it took him ages to get it back in alignment, yes i am scared.any one know any good tutorials ?

If your collimation is fine leave getting knobs till you need them. I only ever needed to collimate my sct once. Full instructions on fitting bobs knobs come with them and collimating an sct is a lot easier than a newt
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E621Keith

E621Keith

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I've got to say the Chinese made Celestrons are really good at holding their collimation. My C925 arrived perfectly collimated over a year ago, and it still is. My C6 has been around for even longer and I only recollimated once after I 'played' with the collimation adjustment. By contrast my US made C8 needed adjustment after a 2 hours drive.

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rowan46

rowan46

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I've got to say the Chinese made Celestrons are really good at holding their collimation. My C925 arrived perfectly collimated over a year ago, and it still is. My C6 has been around for even longer and I only recollimated once after I 'played' with the collimation adjustment. By contrast my US made C8 needed adjustment after a 2 hours drive.

I think we get a little bit nitpicking about it. I think because the weather is so poor we collimate because it gives us something to do. Like keith I have found sct's generally hold their collimation pretty well the small ones even more so. My nexstar 5 vwas collimated once by me and I assume at least once by a previous owner as it had Bob's knobs on when I bought it but then the scope is nearly 20 years old and I carry it around in a backpack usually. If you are getting poor views it's more likely to be cooldown issues than collimation on an sct and even more so on a mak
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faulksy

faulksy

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If your collimation is fine leave getting knobs till you need them. I only ever needed to collimate my sct once. Full instructions on fitting bobs knobs come with them and collimating an sct is a lot easier than a newt

thanks rowan. do you no of any guides to colimate. like you say i think its fine, i do,do star tests and all looks good but you always wonder. thanks
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rory

rory

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just ordered the primary knobs from bobs knobs, if id ordered the secondary too it would have woked out at £30 , which is steep i feel. and i rarely need to mess with the secondary anyway.

has anyone with a 8" skyliner swapped the rubber o rings for springs ?

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Zakalwe

Zakalwe

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My second hand C8 has one fitted and they are very good. Shame they don't have a UK dealer or I'd get it for my other two SCTs.

They only take a few days to get here from the States. I've bought a couple of sets and BK is a great vendor to deal with.

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scarp15

scarp15

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Yes the postage time can be phenomenal. When I ordered Bob's knobs secondary screws and primary springs, I receieved an email to indicate that they would be shipped on a Monday - they were received on the Saturday.

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E621Keith

E621Keith

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They only take a few days to get here from the States. I've bought a couple of sets and BK is a great vendor to deal with.

It's not the shipping that's the problem. It's the post office handling charge that I'm concerned about. Bob's knob + shipping is just expensive enough for Custom to take notice.

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earth titan

earth titan

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are you telling me i might have to pay MORE on top for these knobs ? i hope not ,they are expensive enough as it is without h.m customs getting a bite .

I've never heard of this happening. Wouldn't worry about it.

Typed by me on my fone, using fumms... Excuse eny speling errurs.

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