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Help needed! What is this artefact on my image?


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1 hour ago, AlanP_ said:

difficult

No. It's easy. Once you've the bits and bobs, it takes around 20 minutes, if that.

(I updated the post. Please check the other stuff you'll need to do).

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Looks to me like your focus is way off & the scope is out of collimation? Here's the first image stretched... Cheers Ivor

The first image looks like very out of focus stars.  Not sure why the circle is flattened at the top, have you got a wind shield on that might be flopping over the light path? Carole  

Hi Your first two images are out of focus and with the telescope out of collimation. The last image shows only hot pixels. Maybe start by collimating the telescope; the secondary mirror is n

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So I got setup today again for around 40 minutes total (between setting up and imaging). No proper photos yet, but I sorted out the focusing issue somewhat. I had round(ish) stars! I did a rough polar alignment due to the time constraint and quickly approaching clouds. With the coma corrector, im having to be extremely precise with the focusing. It needs to be absolutely precise to get round stars and I cant use the focus knobs due to the weight of the camera on it - I need to manually move it as slow as possible. Is there a better way around this such as a spacer or something I can use to fill the gap to the perfect focus for the coma corrector? It would make it a lot easier.

Another thing, How balanced does the scope need to be on the mount? Thats another thing ive been having a couple of issues with. 

Much better than the last day and im definitely making some progress. Got setup with platesolver in APT too which I was having trouble with before! The next clear night will hopefully provide my first proper images.

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5 minutes ago, AlanP_ said:

I cant use the focus knobs due to the weight of the camera on it

?

You set the coma corrector at 58mm (which you have already done) from the sensor and leave it screwed tightly into your t-adapter. Then you leave it. 

Focus is always by using the knobs. The coma corrector makes no difference to the method of focusing.

Cheers

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1 minute ago, alacant said:

?

You set the coma corrector at 58mm (which you have already done) from the sensor and leave it screwed tightly into your t-adapter. Then you leave it. 

Focus is always by using the knobs. The coma corrector makes no difference to the method of focusing.

Cheers

Do the focusers not just change the distance from the lens to the mirror?

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I figured it out now. I had the screws too tight on the focuser and I couldnt adjust. Then I loosened them and the camera just fell to the bottom of the focuser. I need to loosen them just a bit and then I can adjust focus with the camera in place. My mistake! That'll make it a lot easier now :) 

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11 minutes ago, AlanP_ said:

need to loosen them just a bit

The screw nearest the telescope tube adjusts the tension of the focuser, the other locks the focuser in position.

Loosen the latter fully until you have reached focus with a tension sufficient to hold your camera but at the same time being able to focus with a little resistence. 

HTH

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2 minutes ago, alacant said:

The screw nearest the telescope tube adjusts the tension of the focuser, the other locks the focuser in position.

Loosen the latter fully until you have reached focus with a tension sufficient to hold your camera but at the same time being able to focus with a little resistence. 

HTH

That makes it a lot easier! Great to know. Thanks again for that :) 

 

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