Image degradation on Raspberry PI HQ Camera

Published on 4 December 2023 at 19:43

lately I noticed strange deformations on my Raspberry PI HQ Camera IR filter that looked like little cracks. I start to investigate what could be the cause of this and found this article. My case was a little diferent though. There were no boubles but deformation looked more like cracks.

Firstly I thought that this is somekind of dust, so I tried to clean it off with isopropyl alcohol and cotton sticks. After cleaning, filter visually looked a little better, but another imaging test revealed, same problem. So I continued the investigation. I already knew that IR filter can be removed, so I searched for instructions how to do that.

In the past I have already consider removing IR filter, because it's not suitable for astrophotography, but I have never realy decided to do it. So this was perfect time to rid of it once and for all. Instructions are well writen and filter was removed in no time. But now imaging sensor was exposed to outer world, and that's a bad thing! So I decided to cut a little cover from transparent plastic to replace the filter. But I soon realised that that was a very bad idea. Quick imaging test showed horrible image degradation caused by that clear plastic.

My next thought was that I should buy some eyepiece filter and mount it on c-mount, to protect imaging sensor. So I started to search and soon found what I needed. Svbony 1.25'' / 2" UHC+CLS+Moon+UV/IR Filters Set.

When filters arrived, I removed protective clear plastic anr reasembled HQ camera with attached c-mount to 1.25" converter on it. C-mount to 1.25" converter enables me to attach standard 1.25" filters to my HQ Camera. Final assembly look like this.

Next step was to attach HQ Camera to Svbony helical focuser. For that I'm using custom designed and 3D printed HQ Camera housing available here.

Now I'm ready for some astrophotography session. I'm hoping for clear skies soon.

Here are examples of images before IR filter removal and after.