scratch on secondary

[irishbloke]

Ok I'm an ijit! I was playing about with my scopes collimation (twas cloudy, twas bored, thought to myself "what can I mess with?" and had read thread on barlow colimating. (Very good by the way, just need to improve my tools)) when disaster struck!

Ok bit OTT, but i managed to scratch my secondary mirror with... (dare I admit it?)... my watch! It's about 1cm on the thin plane from the edge towards middle. I'll try to take a picture tomorrow and post.

• I'm wondering how much effect it will have of my viewing.
  

I had it out last night but moon was on full beam so things were very bright. I did however have a great view of the moon for a while between clouds.

• Is this going to mean a secondary mirror should go on shopping list? If so where would you get one?
  

On plus side I did learn a lot from session and had aligned the secondary in the tube better by adjusting spider vanes. I was probably losing a cm or 2 of edge of primary. Then with the barlow collimation I think I got that nailed. Bright stars still seemed a little a little of points of light but thats probably my eyepeices.

Overall, I don't have that sick feeling you get when you know you've really . I actually feel if I had to change mirrors I could!

[GazOC]

It won't have much of an impact on the views you are getting, but IF you think you can get some black ink (say from a marker pen) into the scratch to cover it over without getting it on the mirror itself then it wouldn't go amiss and would help stop any wayward reflections.

[barkis]

Forget it, it won't degrade the system one iota, I know it will irritate you for a while, but time is a great healer. There is nothing short of coating removal and/or polishing it out that will correct it, so

try to put it out of youir mind. Gaz. is right though, try to black it out as finely as you can, but if you are loathe to do that, then don't.

Ron.

[Merlin66]

If you can post a photo...

Might help us allay your fears....

[Astro_Baby]

If its on the mirror edge - the bit that faces the side of the tube you could always paint out the edge oif the secondary with blackboard paint. Like this...

You need a very steady hand for this.

[dweller25]

It will have no effect at all on the performance of your scope. I would just leave it alone.

[irishbloke]

Hi got a photo.

I was also wondering if now that I have bravely taken it out once, would it be worth blackening the sides of the mirror. If so would a black permanent marker do it?

Thanks

Brian

[dweller25]

Yes permanent marker will do it - I did mine a couple of months ago - I also flocked opposite the focuser and contrast is now improved.

[Astro_Baby]

Thats as good a reason as any I have seen to always remove jewellry when messing with optics and always wear cotton gloves (£1.99 from Boots).

[irishbloke]

Thanks Astro Baby,

I feel a bit of a tool already!

Also I'm wondering about your collimation guide. The link no longer works and I was wondering if you had a copy you could email me? It was great and I really should have saved it when I read it!

Thanks

[ollypenrice]

I think one should always look THROUGH telescopes rather than AT them. Like the others, I strongly suspect that your view will be unaffected. Totally, that is. Get out there and get looking!

Olly

[Astro_Baby]

Doh ! Soz I didn't mean to make you feel bad there sowwy - the guide is moved onto my own site now.

Its here Astro Babys Guide to Collimation

Hope thats some help.