spots

[mason]

Hi there,

Out today doing some solar imaging with a c9.25 sct and a mono imaging sourse cam and an off axis white badder film over the aperture. When i brought the image into focus with low exposure, there was lots of small black dots with white rings round in view. (not sunspots!)

I could not work out where these were coming from. Could it be dust on the imaging chip or dust from the corrector plate? i rotated the camera and they didnt move, but surley it cant be from the corrector plate. Any ideas?

[Glen]

Sounds like dust motes on the cam chip or there about mason. Was going to mention rotation to find out what part is the issue but you've done that have you got a dust blower[?] they are only a few quid if not.

[mason]

hi glen, yeah i have a blower, gave it a blow, and it didnt go!!

[Glen]

I don't suppose you have a pic?

if not have you tried taking flats?

[mason]

sun0004 14-55-40.bmp

[Glen]

To show on here.

It is a lot of summing, blimey what concerns me is they are not all focused:icon_scratch:

Do you use filters as well?

[mason]

only a badder solar filter. the pic has quickly been processed in registax just to get it on here, but you get my drift! have no idea!

[mason]

just tested my camera, and its coming from my that! must be broken!! if i shine a light into it, it is full of those circles on the screen!

post edited for language, hope you dont mind, nightfisher

[Glen]

Best guess is something on the imaging chip if you rotated the cam and the spots rotated with it. Might be worth getting a dry cotton bud and doing a single (very soft l!) swipe on the lens surfaces ending up on the chip, taking shots after each 'swipe' although not for the feint hearted! And wise to use baader fluid.

Other than that I'm at a bit of a loss.

Edit good to read ^

[David JM]

To me it looks like the image is focused on a pane of glass with something in the background.

Did you get a sharp focus on the edge of the sun before going for the sunspots? Did you replace the eyepiece and not refocus?

[Photosbykev]

Dust bunnies on the sensor sometimes have the halo which seems to be formed by an oil residue. Careful cleaning with proper cleaning fluid and swabs will remove them

[mason]

yep its dust bunnies, full of them. cheers guys.