I cleaned my primary mirror successfully!

[mbaddah (Mo)]

Well I was extremely hesitant in cleaning my primary mirror for the 10" LB, but it was looking so filthy I couldn't bare to look at it anymore and took the plunge of cleaning it (for first time).

Printed out Mike Salways guide (a big thank you to you Mike) and followed it step by step. Whilst its not 100% clean (should have left it to soak a little longer) it's far cleaner than it was before.

The only time I side tracked from Mike's guide was when removing the primary, I simply unscrewed the 3 clamps inside the tube holding the mirror and simply lifted it straight up (ofcourse been careful). I didn't want to undo the collimation screws and anything as I'm quite clumsy with these things

Thanks again Mike

[iceman (Mike)]

Well done! I'm glad you found the article useful!

Don't forget you will still need to re-collimate when you put the mirror back in.

I love using a clean mirror for the first time after a wash.

[supernova1965 (Warren)]

From that last photo it looks like you left a spider in the tube

[mbaddah (Mo)]

Originally Posted by iceman

Well done! I'm glad you found the article useful!

Don't forget you will still need to re-collimate when you put the mirror back in.

I love using a clean mirror for the first time after a wash.

Very useful indeed looking forward to it's first light after this rain disappears

Originally Posted by supernova1965

From that last photo it looks like you left a spider in the tube

LOL!

[astronut (John)]

Looks great Moh,
Don't worry too much about the couple of spots left over.
Here is my mirror ..........but the views are still brilliant!!

[mbaddah (Mo)]

lol looks like it good do with a good clean John

Originally Posted by astronut

Looks great Moh,
Don't worry too much about the couple of spots left over.
Here is my mirror ..........but the views are still brilliant!!

[Sarge (Rod)]

I was thinking about cleaning my 12" mirror, but after seeing yours John, I think I'll leave it for a while yet.

Rod

[mbaddah (Mo)]

After having cleaned my mirror and taking the scope out a few times, I've noticed a ghosting/flaring effect around bright objects (e.g. Saturn, Sirius etc...) which I hadn't noticed prior to the cleaning.

Could this be due to the tightening of the clamps on the primary or some other reason?

[Starkler (Geoff)]

That or collimation maybe.

Do a check with a defocused star and see that the rings are nice and round blah blah blah.

[mbaddah (Mo)]

Originally Posted by Starkler

That or collimation maybe.

Do a check with a defocused star and see that the rings are nice and round blah blah blah.

Collimation is dead on as confirmed by my Astrosystems laser collimator and Orion chesshire. Stars were nice round rings

[Starkler (Geoff)]

Originally Posted by mbaddah

. Stars were nice round rings

When looking for signs of pinched optics it might not show up unless you're focused down to a small number of rings. Watch the shape as they collapse down as you rack through focus and out the other side. If they stay round all the way then thats fine. Any distortion of shape that flips orientation on the other side of focus may be indicative of pinched optics or astigmatism.

[astronut (John)]

Moh,
Did you rinse it properly?
When you placed the primary back on the cell did you overtighten the primary clips, if yes, back them off so that you can fit a business card under the clips.
Check that all e/p's and secondary are free of marks.
If all else fails, bring it to the next observing night at Stargard.

[barx1963 (Malcolm)]

When I cleaned my primary a few weeks back I overtightened the clamps. Found when I just defocused a fairly bright star the shape was like a clover leaf. Even in focus, evrything looks weird and stars anywhere ouside the dead centre of the FOV looked bloated. Backed off clamsp about 1 turn and it fixed it.

[mbaddah (Mo)]

I unscrewed the clamps a little on the primary, re-checked the collimation and gave it another go a few days ago. It seemed to have improved, although not sure if it's 100% the same as it was before or not.

I'll show you how it looks John at our next meeting and you can tell me what you think Although I'm starting to think I may also have a not-so great primary mirror from Meade now when comparing the image of M42 against my previous 6" dob. If my memory serves me correct the image in the 6" showed more detail (not brighter) than my current 10", which clearly shouldn't be the case. I'll have to compare it against your 12" John too

[Starkler (Geoff)]

Originally Posted by astronut

did you overtighten the primary clips, if yes, back them off so that you can fit a business card under the clips.

Egh I cringe everytime I see that often repeated bad advice posted
Its one of those telescope forum quotes thats been going around for years and just wont die.

Encouraging people to test a gap by attempting to jam a business card into it is NOT a good idea and is likely to scratch or scuff the mirror. This is not like setting a spark plug gap!

Suffice to say the clips should not be tightened down to clamp the mirror and that they only exist to prevent the mirror from falling out of the cell so no pressure is required or desired.

[astronut (John)]

Originally Posted by Starkler

Egh I cringe everytime I see that often repeated bad advice posted
Its one of those telescope forum quotes thats been going around for years and just wont die.

Encouraging people to test a gap by attempting to jam a business card into it is NOT a good idea and is likely to scratch or scuff the mirror. This is not like setting a spark plug gap!

Suffice to say the clips should not be tightened down to clamp the mirror and that they only exist to prevent the mirror from falling out of the cell so no pressure is required or desired.

Geoff ,
I give people more credit than this, not to "jam" anything in or around their mirror.
I and many others have used this method for many years without damaging their optics.