is my mirror screwed ?

[Somnium (Aidan)]

Recently i was taking a picture and could not achieve focus, it was frustrating me and i tried everything to resolve it. eventually i thought it might be my secondary mirror covered in dew. i took a microfibre cloth and wiped it. i since worked out that the issue was that one of the collimation bolts was too tight and it was actually distorting the mirror (a big concern). anyway, i loosened the bolt and it cleared up the issue. However, on my next image i noticed streaks seen here
http://www.iceinspace.com.au/forum/a...e.php?a=171728

located in the top right of the galaxy.

so i thought that i might have put some dirt on my secondary mirror and decided to clean it properly. i used water and damp cotton wool as per the instructions in a recent Sky and telescope magazine. the result ...

https://www.facebook.com/61868816154...type=1&theater

it is much worse

my question is, do i bother purchasing a cleaning kit and try to fix it or is the mirror completely stuffed up? given that it is less than $50 to get a new one i might as well do that.

[glend (Glen)]

Water alone is not going to remove much, including the notorious gum sap. Try cleaning it with warm soapy water and rinse with distilled water, or acetone ( on the mirror surface only). How old is this secondary?

[Somnium (Aidan)]

it is only about 6 months old

Originally Posted by glend

Water alone is not going to remove much, including the notorious gum sap. Try cleaning it with warm soapy water and rinse with distilled water, or acetone ( on the mirror surface only). How old is this secondary?

[bojan]

Those streaks has nothing to do with mirror.
It is readout noise, generated in camera.
Check your USB cable!

We discussed those streaks earlier on this forum.. I will post a link when I find it

[Somnium (Aidan)]

Really ?? i would love to see that thread

Originally Posted by bojan

Those streaks has nothing to do with mirror.
It is readout noise, generated in camera.
Check your USB cable!

We discussed those streaks earlier on this forum.. I will post a link when I find it

[doppler (Rick)]

I had an old scope and the coating on the secondary had cracks and was starting to peel, but it never showed up in the images. A dirty mirror just makes the image duller.
But thats a nice shot of Ngc 253
Rick

[Somnium (Aidan)]

Thanks for that

i will try replacing the cable and see if that helps

Originally Posted by doppler

I had an old scope and the coating on the secondary had cracks and was starting to peel, but it never showed up in the images. A dirty mirror just makes the image duller.
But thats a nice shot of Ngc 253
Rick

[bojan]

Originally Posted by Somnium

Really ?? i would love to see that thread

I cant find this discussion any more, it took place some time ago.
However, have a look here:
http://www.cloudynights.com/topic/47...ntial-banding/
The effect is called "banding", and it becomes visible after applying excessive stretching.
Nothing to do with optics.
Dirty mirror will only (somewhat) reduce the contrast, and add some haze (your stars would look bigger.. )

EDIT:
For some reason, searching is working now :-) (I swear it did nor work yesterday)

So, have a look here:
http://www.iceinspace.com.au/forum/s...hlight=banding