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Secondary mirror reflection on Reducer


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Hi colleagues!, 

 

Nor sure if this is the right place to put this on but I'll give it a crack.

 

I'm getting this weird reflection of the secondary mirror and spider veins on the focal reducer of my telescope, or filter, don't know where the reflection is honestly, I know that when you aim to a bright star you might get a flare reflected. 

Mi current imaging train is like this: Camera+Filter Drawer+Extension+Reducer+Extension+focuser.

For some reason, it doesn't matter how I configure this set up I always get that reflection on my image, not sure if this can be removed with flats as I haven't tried that yet. has anyone came across with something similar, and, how did you solved it?.

I hope the photos makes sense of what I'm talking about!.

 

Thanks a lot for taking the time to read and help!.

 

Clear skies!.

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Hi @Felipe

Diffraction spikes are 'normal' with 'scopes when the secondary is held in place by a spider, as per your first image. They are a love/hate artifact by some.

As for the rings in the second image, I have only seen them when used with a catadioptric lens or 'scope. I believe/think it is to do with the placement of the camera imaging sensor and focal reducer on the 'scope creating internal reflections. 

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36 minutes ago, Philip R said:

Hi @Felipe

Diffraction spikes are 'normal' with 'scopes when the secondary is held in place by a spider, as per your first image. They are a love/hate artifact by some.

 

I don't think Felipe is talking about the diffraction spikes.  In his second photo he has arrowed what appear to be short dark lines at the 4 cardinal points - exactly where the 4 vanes supporting his secondary would be.  Not seen this myself and no idea how to fix it as I have an SCT.

Graeme

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3 minutes ago, jacko61 said:

I don't think Felipe is talking about the diffraction spikes.  In his second photo he has arrowed what appear to be short dark lines at the 4 cardinal points - exactly where the 4 vanes supporting his secondary would be.  Not seen this myself and no idea how to fix it as I have an SCT.

Graeme

Oh yes!

I have just had a closer look at the first image and I can now see it. :BangHead:

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hey!, yes, so for some reason the spider veins are casting a shadow over the reducer, as soon as I remove the reducer the reflection of the donut disappears along with 4 spider veins shadows, somebody mentioned in other forum that the whole cam+drawer+exten+reducer was too far in the focuser, maybe i'll try to put it a bit further out, funny that I got it now as I used the same configuration previuosly without any issue.

 

Thanks guys!.

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