Telescope Reviews: C9.25 Edge collimation screws

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Equipment Discussions >> Cats & Casses

Pages: 1

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

C9.25 Edge collimation screws
#5274394 - 06/16/12 01:49 PM

Anyone know what size to use for both length and width? I am hoping to use an allen head type. One reason why length is also important is so that it doesn't dig into the back of the secondary housing. Many thanks!

Post Extras:

Peter in Reno
Post Laureate

Reged: 07/15/08

Loc: Reno, NV

Re: C9.25 Edge collimation screws new

[Re: ewave]
#5274423 - 06/16/12 02:10 PM

They are M3 metric screws. Since you are going to replace the screws, you will have to re-collimate the scope anyway, so remove one of the screws to measure the length. If local hardware stores do not have the screws you are looking for, you can easily get them from http://www.mcmaster.com/#socket-head-cap-screws/=i06jzl . They deliver incredibly fast. For stainless steel socket head type, this is what they have:

M3—Pitch: 0.5 mm

Length Qty Part # Price

4 25 92290A108* 12.80
5 50 92290A110* 11.62
6 50 92290A111* 9.44
8 50 92290A113* 9.63
10 50 92290A115* 9.99
12 50 92290A117* 9.99
14 50 92290A118* 6.57
16 50 92290A120* 10.90
20 50 92290A122* 11.44
25 50 92290A124 13.44
30 25 92290A126 10.17
40 25 92290A128 11.17
50 25 92290A130 11.66

I am willing to bet the length of screws for EdgeHD is different than regular SCT so I would measure yours to be sure.

Peter

Post Extras:

Tanveer Gani
scholastic sledgehammer

Reged: 11/02/06

Loc: Washington State

Re: C9.25 Edge collimation screws new

[Re: ewave]
#5274485 - 06/16/12 03:18 PM

The c11 HD ones were 12mm m3 iirc.

Tanveer

Post Extras:

Peter in Reno
Post Laureate

Reged: 07/15/08

Loc: Reno, NV

Re: C9.25 Edge collimation screws new

[Re: Tanveer Gani]
#5274544 - 06/16/12 04:03 PM

I have Bob's Knobs for my C-8 EdgeHD but I have not yet installed them. They are M3 and 12mm long like Tanveer's C-11 EdgeHD. There's a good chance yours are M3 and 12mm long.

Peter

Post Extras:

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

Re: C9.25 Edge collimation screws new

[Re: Peter in Reno]
#5274650 - 06/16/12 05:33 PM

Thanks for your comments Peter & Tanveer.
Funny thing is I have a pair of Bobs knobs for my ex C11 somewhere but don't think they will be a fit, even if they are metric. I will take one screw out at a time while replacing each one as I go, or I could simply remove (unscrew) the secondary fastar assembly to be safe.

Post Extras:

RAKing
Postmaster

Reged: 12/28/07

Loc: West of the D.C. Nebula

Re: C9.25 Edge collimation screws new

[Re: ewave]
#5274657 - 06/16/12 05:41 PM

Quote:

Thanks for your comments Peter & Tanveer.
Funny thing is I have a pair of Bobs knobs for my ex C11 somewhere but don't think they will be a fit, even if they are metric. I will take one screw out at a time while replacing each one as I go, or I could simply remove (unscrew) the secondary fastar assembly to be safe.

You could do that - but the other reason to replace one screw at a time is it's so much easier to keep everything in order doing one at a time.

Remove and replace one screw and tighten it up until the scope is back in collimation. Repeat with the others until done. It's much simpler that way.

Cheers,

Ron

Post Extras:

PhilCo126
Carpal Tunnel

Reged: 01/14/05

Loc: coastline of Belgium

Re: C9.25 Edge collimation screws new

[Re: RAKing]
#5280836 - 06/20/12 02:43 PM

I've seen observers remove the (FastStar system) secondary mirror on a C 9.25 EDge HD by just unscrewing it, placing it back correctly and no collimation was needed...

Post Extras:

Eric Gage
scholastic sledgehammer

Reged: 12/13/05

Re: C9.25 Edge collimation screws new

[Re: PhilCo126]
#5281662 - 06/21/12 01:07 AM

Quote:

I've seen observers remove the (FastStar system) secondary mirror on a C 9.25 EDge HD by just unscrewing it, placing it back correctly and no collimation was needed...

There is a hyperstar video that states that collimation will not be necessary before and after removal of the primary. I'd be interested to see if this is the case. Did you look through such a scope after the secondary was manipulated?

Post Extras:

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

Re: C9.25 Edge collimation screws new

[Re: Eric Gage]
#5281738 - 06/21/12 02:17 AM

Quote:

Quote:

I've seen observers remove the (FastStar system) secondary mirror on a C 9.25 EDge HD by just unscrewing it, placing it back correctly and no collimation was needed...

There is a hyperstar video that states that collimation will not be necessary before and after removal of the primary. I'd be interested to see if this is the case. Did you look through such a scope after the secondary was manipulated?

Yes, it's true. The secondary assembly simply unscrews. It remains collimated as long as you handle with care and don't bump the secondary into something. A very nice feature indeed.

Post Extras:

PhilCo126
Carpal Tunnel

Reged: 01/14/05

Loc: coastline of Belgium

Re: C9.25 Edge collimation screws new

[Re: ewave]
#5282330 - 06/21/12 01:54 PM

Indeed it works with a marker setting so You put the secondary assembly correct in its place before turning the ringholder in place... Will look through one next time I get the chance

Post Extras:

wolfman_4_ever
Pooh-Bah

Reged: 07/15/11

Loc: El Segundo, Ca, So. Cal

Re: C9.25 Edge collimation screws new

[Re: PhilCo126]
#5284027 - 06/22/12 03:08 PM

Humm.. How come Bob says they are only 9.5mm long? The HD8 and 11 show 12mm screws but the HD9.25 says 9.5mm..

http://www.bobsknobs.com/Celestron/SCT/C925edg.htm

Post Extras:

Peter in Reno
Post Laureate

Reged: 07/15/08

Loc: Reno, NV

Re: C9.25 Edge collimation screws new

[Re: wolfman_4_ever]
#5284081 - 06/22/12 03:58 PM

I believe that's diameter of the knobs, not length of screws.

Peter

Post Extras:

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

Re: C9.25 Edge collimation screws new

[Re: Peter in Reno]
#5284362 - 06/22/12 07:24 PM

Quote:

I believe that's diameter of the knobs, not length of screws.

Peter

Nope I took mine out just to see and they are less than 1/2 inch long (I think it was exactly 3/8") so that may be correct....9.5mm stinks.
I still have to order but tried a couple of stores with no luck yet.

Edited by ewave (06/22/12 07:26 PM)

Post Extras:

Peter in Reno
Post Laureate

Reged: 07/15/08

Loc: Reno, NV

Re: C9.25 Edge collimation screws new

[Re: ewave]
#5284370 - 06/22/12 07:35 PM

OK. I saw the link to the web site Dave provided and it said "diameter". Is the web site incorrect?

Peter

Post Extras:

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

Re: C9.25 Edge collimation screws new

[Re: Peter in Reno]
#5284452 - 06/22/12 09:09 PM

Quote:

OK. I saw the link to the web site Dave provided and it said "diameter". Is the web site incorrect?

Peter

Peter
I dont have Bob's knobs for my C9 edge but it wouldnt surprise me that the width of its head is 9mm. But my guess is the Bob's knobs are longer in length because the head part must protrude outside the screw's housing.

Edited by ewave (06/22/12 09:12 PM)

Post Extras:

wolfman_4_ever
Pooh-Bah

Reged: 07/15/11

Loc: El Segundo, Ca, So. Cal

Re: C9.25 Edge collimation screws new

[Re: ewave]
#5284831 - 06/23/12 06:00 AM

Ya. Diameter. Sorry about that.

Post Extras:

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

Re: C9.25 Edge collimation screws new

[Re: wolfman_4_ever]
#5285918 - 06/23/12 09:10 PM

OK I found a True Value hardware store that has SS Metric M3 (0.5mm pitch) at 10mm length (a hair longer than the factory ones) and yes, they are allen heads. Only cost me 42cents each. Only thing that concerns me is they went in pretty easy which may suggest that they wont hold collimation for too long. Perhaps I can add a touch of silicone to tighten up that hold a bit. The only way to find out if it holds is time. I'll keep you posted.

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