M37 Open cluster--- sensor clean test

[menardre]

My last few imaging sessions I noticed a couple of blurry 'blobs' on the far right of my flats. I was hoping it was only 'dust bunnies' on the optics, but It turned out to be real 'blobs' on the actual imaging sensor...not good.

So I took the ZWO ASI2600 apart (remove the front window), and found that it appeared to be some kind of leakage. I have sensor cleaning equipment that I have used on my Nikon camera, so I gave sensor cleaning a try. This involves simply putting a few drops of sensor cleaning fluid on a special tab/swipe. Then carefully drag the swipe across the sensor in one continuous motion. While this sounds easy, you usually leave behind some streaks, so you have to carefully work at it. I was able to clean the sensor and could not see any obvious defects. While I had the camera apart, I re-charged the desiccant tablets by microwaving them for 2 minutes. I then re-connected the camera to the scope and took some flats to verify. I did notice some very faint irregularities, but I did not think they would show up in a final image.

So, in order to test the sensor cleaning I decided to image an easy object, the open cluster M37. I picked this since I knew I would only have an hour or two of imaging due to clouds. I took 60 images at 1minute exposure, binned 1x1, at -10C using SVX130 refractor. I also took 50 flats 0.1 seconds.

Then image processed using PixInsight was very straight forward since there is no nebulosity to try and bring out. Result did not show any signs of sensor 'irregularities'... I even tried to push the stretching to see if I could detect anything. So far so good.

M37 (NGC 2099) is actually an interesting open cluster. It is the brightest and richest open cluster in Auriga.

Just thought I would share my sensor cleaning task

Roger

M37 Open Cluster1.jpg (10.4 MiB) Viewed 2034 times

[Pete]

Hi Rog, the ASI 2600 series cameras have had frequent reports of oil migrating onto the sensor. This can be visually detected simply be inspecting. Sounds like what you've encountered??? The fix is simply to do what you've done. It's pretty accessible.

[menardre]

Pete

Thanks... I did a google search and found the reports you were talking about. I am going to contact ZWO to see if they will clean/repair the sensor.

ZWO also indicates they have changed their manufacturing processes to eliminate the problem.

Thanks,,,

Roger

[menardre]

Pete

Thanks for telling me about the reports of oil leaking onto the sensor of ZWO cameras. It turns out that some ZWO cameras have an excess of thermal grease between the back of the sensor and the thermal pad. If the camera gets hot enough the thermal grease can 'melt' and sometimes end up on the sensor. This is apparently what happened to mine.

ZWO will replace the camera if it is less than 2 years old, or otherwise they will have it repaired. Repairing simply means taking the camera apart and using a q-tip, remove any excess thermal grease, along with cleaning the sensor.

ZWO has indicated they have changed their procedures to minimize thermal grease.

Roger

[Pete]

My ASI2600MC-P is almost 3 years old. And some oil/grease is starting to migrate from the edges of the chip toward the working part of the sensor. This has been going on for a while now and I've not been keeping close track of it. If it does get onto the working part of the chip I plan on simply taking things apart and cleaning. The procedure's quite straightforward. If you'd like for me to clean your camera Rog, I'm at your disposal. Sending it back to China involves a long turnaround.

[menardre]

Pete

I took the ASI2600 apart again and this time spent some time cleaning the sensor per ZWO instructions.

I then attached to my scope and took some flats. Looks much better and clean.

Thanks for offering.

Roger

[Pete]

Didn't know that ZWO had a "fix" out on the grease problem. Could you please provide a link?

[menardre]

Highpoint Scientific posted a video showing how to clean the sensor.

Here is the link

https://www.youtube.com/watch?v=3VbTEcL5qcY


Roger

[Pete]

Thank you Roger. This may come in handy should my grease migrate onto the working part of the chip.

By the way, I didn't agree with removing the grease from the back of the chip. Removal completely defeats the purpose for which it was applied in the first place.

[menardre]

Pete

I agree with you regarding removing the thermal grease. I simply cleaned the sensor... if more grease gets onto the sensor, I will clean it again.

Roger