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Poor images after cleaning primary mirror


rodgerK
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Hi

After 4 years of use, it seem time to give my Skywatcher PDS200 mirror a cleanup. 

First issue -  I could not get the primary mirror housing to come away from the tube after releasing the 6 screws. So I resorted to a "quick" washed with the mirror sitting loose in the tube using first soapy water and then de-ionised water applying it with cotton wool pads (changing frequently).

It looked better, although I could see spotting still which I took to be just an age thing.

I then recolimated with a lazer and tried again.  After poor results I did the whole thing again a second time.  However, I am still not happy with the results.  I attach a B/W of the Cocoon Nebula done ~ 2 years ago and one of the Flame Nebula in LRGB last night (with a strong moon).  Both cases used an Atik314L+ as the camera and I use PHD Guiding with a QHy5 on my finder so the tracking was good.  In fact the latest picture only used 30 sec subs.  I also used a bartinnov mask to ensure a good focus.

The stars in the latest picture do not appear pinpoint enough and seem too broad and "lumpy".

Is this a sign of a damaged surface caused by the cleaning or something else -  or am I just being neurotic :huh: ?

Rodger

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Looks like just slightly off collimation of the scope and slightly off guiding as mentioned above. Check your mount's leveling, alignment and balance. I see nothing in the picture that would indicate damage to the primary mirror. Next time i would really try to carefully remove it all the way out to clean it though.

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