Help please! Some circle is messing with my images [Deep Sky] Acquisition techniques · Fernando · ... · 28 · 1335 · 4

andreatax 7.46
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Do not worry about the size of your secondary. Mine is 36 mm and I don't have any issue with it using the same sensor of yours. I think the issue is more on right processing with the right software than anything else. In other words, even if the problem persists you know there is a way to deal with it.
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andymw 11.01
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I also agree with Andrea ... I think the secondary mirror size thing is misleading.  I would re-take your flats and darks and see if that helps though.
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Padraic_M 1.20
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I have recently started using a 150PDS and had light leak issues. The primary end certainly lets light in but you seem to have sealed that adequately. I had no issues with the front cap when shooting darks.

The main issue for me was the focuser drawtube - it leaks light when taking flats especially if you use a LED panel.
A likely solution is to wrap tin-foil around the drawtube joint when taking flats. Another PDS owner uses a velcro strip, which could potentially be left on when taking lights as well, allowing some flexibility for autofocusing. I have to assume that if a lot of light leaks in with taking flats, a small amount can leak in when imaging (especially if there are street lights or ambient lighting around).

The focuser light leak looked very similar to that blue streak in Andrea's processed version but a little softer. The key point is that it was not a circle, it was an off-centre line or streak.

To test everything, loop 1 second exposures in e.g. NINA. Take a bright flashlight and shine it on every joint on your OTA and camera. You will see the light damage in the looped image.
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Juiancasal 0.00
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Esta colimado? Los reflejos de las estrellas son raros
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