Impurities on the ccd sensor?

[Mr Giovanni Di Giovanni]

Hello everyone
Today I tried to photograph the solar disk with my Sky Watcher mak90, from the balcony of my house. Very clear day, exceptionally blue sky. At direct focus (no other optics interposed) a good old nikon D3000 (only 12000 shots). Because my equipment is really unsuitable, or perhaps very bad, but also because I am not an expert in photographic shots, I obtained frames of fairly poor quality. One of them and two enlargements are attached. What I would like to ask is if anyone can give me any indication as to the presence of all those rings that appear scattered over the photosphere. I thought they were caused by dust on the sensor; but they appear in all the other frames in the same positions in relation to the spots (distinguishable though poorly photographed), on the solar disk positioned differently from the sides of the sensor.
Thanks

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Attachments:

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   DSC02819A.jpg
   

2. 

   DSC02817A.jpg
   

3. 

   DSC02817B.jpg
   

[Dawson]

It is dust and dirt in the optical path somewhere. Things directly on the sensor can appear nearly focussed, things on the lens of a refractor can appear grossly out of focus. These things look to be between the two. Are you using any filters near the sensor?

[Mr Giovanni Di Giovanni]

Yes, I have thought about that. However, the question arises from the fact that those spots are also on other frames with the sun disc shifted inside the frame. The enlargements DSC02817A B, are from a different frame from the attached DSC02819.

[David Arditti]

Yes it is dirt somewhere in the optics near, but not on, the sensor. It seems to shift with the solar disk because it is casting a shadow on the sensor.

[Robin Leadbeater]

Hi Giovani,

The dust donuts are almost in focus so if they are not on the sensor I think they must be on a surface close to another focal plane in the system. Can you post full frames (not cropped) of both DSC02817 and DSC02819 please ?

Cheers
Robin

• This reply was modified 4 days, 3 hours ago by Robin Leadbeater.

[Mr Giovanni Di Giovanni]

Dear fellow astrophiles, you are right. I let my impatience betray me. I did not evaluate the other frames well. In the frame attached here (and also in the others) the solar disc is shifted but the spots remain on the same points of the frame.
I thank all of you for your attention and apologise for my carelessness.
The great Napoleon was right when he told his servants: dress me calmly because I am in a great hurry.

Attachments:

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   DSC02812A-scaled.jpg
   

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