I have a PST (40mm)... Need to clean scope

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RonDzen
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I have a PST (40mm)... Need to clean scope

Post by RonDzen » Sat Aug 29, 2015 3:13 pm

I am new to solar H-Alpha viewing. I have a Coronado PST (40mm).

The backend of the scope requires cleaning. I have used "air in the can" and a lens cloth. But the spots still display in my CCD images. What should I use to clean the lens? I don't want to remove any of the coating.

Any help is very much appreciated.

Thank you!!!

DavidG
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Re: I have a PST (40mm)... Need to clean scope

Post by DavidG » Mon Aug 31, 2015 8:25 pm

A Q-tip that is only slight damp with isopropyl alcohol can be used to clean the surface of the filters without any damage.
It is possible that the spot your seeing are on the ITF filter and the coating are known to go bad. The ITF filter is not the small 5mm that you see when you remove the eyepiece and look into the eyepiece tube. The ITF filter is located below this top filter and about 12mm in diameter. You either have to unscrew the eyepiece tube from the body of the scope or remove the side cover to see the filter. If the filter looks cloudy or blotchy the coatings have gone bad and it should be replaced. If you can get the eyepiece tube to unscrew from the body of the scope and also unscrew the top section that contains the small 5mm filter from the bottom section that contains the ITF filter, you can take an image and then rotate the top section and see if the spot moves with it. Then you'll be able to tell which filter the black spots are coming from.

- Dave
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marktownley
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Re: I have a PST (40mm)... Need to clean scope

Post by marktownley » Mon Aug 31, 2015 8:25 pm

The spots are more likely to be dust on the CCD chip rather than on the PST. Do you have an image you have taken that shows the dust spots?
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

RonDzen
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Re: I have a PST (40mm)... Need to clean scope

Post by RonDzen » Mon Aug 31, 2015 9:28 pm

DavidG and marktownley,

Thank you both for your reply to my query. I have just received an quick education as to the workings of the PST. Thank you DavidG. I will take a shot at cleaning the 5mm lens first, I think this is where the problem resides - as the scope in not more than a few months old. Given its still under warranty, I'll send it to Meade to check the 12 mm lens. If the issue resides there.

marktownley: The CCD camera, I don't believe, contains the spots. I originally thought it was the CCD at first as well. I have turned the CCD camera 90 to 180 degrees and the spots remained on the sun disc in the same area. Also, the spots do not display when using my visual scope - taking pics of moon.

I attached an image of the sun (taken on a very hazy day). I think that "can of air" caused my problem.

You guys are the best and I really appreciate your finding the time to quickly respond to my post.

Thank you again,
RonDzen
Attachments
Spots.jpg
Spots.jpg

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marktownley
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Re: I have a PST (40mm)... Need to clean scope

Post by marktownley » Tue Sep 01, 2015 5:44 am

Are you using a barlow?
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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