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Black spot in centre of my planet image

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Black spot in centre of my planet image

Postby andy will on Sat Feb 04, 2012 2:54 pm

I am a complete beginner and have acquired a Celestron Nextstar 8 SE TELESCOPE. It is in excellentcondition. when I view through it I seem to get a black spot in the centre of the image. This has happened when I see Venus and Jupiter and the moon. My starting point.

I dont know why it is there or how to remedy it. Its as though the central cap on the class is blocking the image.
Please can someone help me with some advice to try and solve the issue?

Thanks in anticipation of your advice.
andy will
 

Re: Black spot in centre of my planet image

Postby andy will on Sun Feb 05, 2012 3:02 pm

Sorry no offence meant. I did n't realise. I'll get to learn as I meet other beginners needing advice.
andy will
 

Re: Black spot in centre of my planet image

Postby Jne_K on Mon Feb 06, 2012 7:58 am

Hi Andy

Glad to help.

Yes, that is a shadow being cast by the secondary mirror (under the black cap). It can happen on very bright objects or if using very low magnifications with high exit pupils. It is completely normal and nothing to worry about. It can happen on any telescope that uses a secondary mirror - SCT, Mak, or reflector. If it annoys you, just move the shadow off to the side when viewing an object.
Thanks for posting with us
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