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How to locate the Dust Bunnies

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Starry Jack
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How to locate the Dust Bunnies

Post by Starry Jack » Sun Nov 03, 2019 5:31 pm

Where are these vicious little creatures? I have cleaned every optical surface I can think of and tried rotating every element in the optical train I can and I can't find the little beasties.

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2019-10-26_8-51-04 Dust Bunnies.png
2019-10-26_8-51-04 Dust Bunnies.png (1 MiB) Viewed 207 times
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Re: How to locate the Dust Bunnies

Post by bart1805 » Sun Nov 03, 2019 6:20 pm

Most of the time it is the camera. So check what you see if you aim just the camera to a light source.
Did you check the sensor or cleaned only the protective window?

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eroel
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Re: How to locate the Dust Bunnies

Post by eroel » Sun Nov 03, 2019 8:00 pm

Jack:
Check the camera (the chip protecting window) those dust motes are from near the chip.
Regards,
Eric.

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Re: How to locate the Dust Bunnies

Post by Carbon60 » Mon Nov 04, 2019 4:04 am

Jack,

Many of these should be able to be removed from the sensor with a few blasts of compressed ‘air’ from a can. However, static charge can hold some stubborn ones back in which case a few squirts from an anti static gun (as for vinyl records) and then air blasts should remove these. Really stubborn ones may require a wipe with a lint-free cloth and treatment as above. My sensors are absolutely spotless following these procedures, although often it takes quite a few rounds to remove them all. BTW, I enclose my camera sensors by attaching a clear neutral filter to the nosepiece to keep them as clean as possible.

Good luck.

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Re: How to locate the Dust Bunnies

Post by marktownley » Mon Nov 04, 2019 6:03 am

Those bunnies are on the chip Jack
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Re: How to locate the Dust Bunnies

Post by Merlin66 » Mon Nov 04, 2019 9:52 pm

I've just spent the best part of three days removing dust motes from my ASI 1600!!! A real pain, and very frustrating.
I found after cleaning all three surfaces (front/ rear protective glass + CCD chip cover plate) -they were still there!
I also found during testing that the results would change??! There's complete cloud down here with no Sun to test the camera in Ha.

I set up an ST80 with the translucent bag cover and the camera with nose piece...looking at a "bright" clouded sky.
First test showed the small bunnies....after couple of cleaning sessions, it actually looked pretty good - no obvious spots.
I then added the x2.5 PM (as per usual imaging arrangement) and.....horror, sinking feeling....the small bunnies were back.
Nothing to do with the PM, but I assume the f12.5 light cone (v's f5 for the ST80) made the difference.

I then tested the CCD chip without the protective cover glass, sure enough still some small motes - cleaned two, three times ( I think the comment above about static is correct) before I could finally say the CCD was clean.....(When you blow the CCD where does the dust motes go? To the side and below the electronics? There are no seals within the body.)

Then added the front cover glass, and found some remaining motes, removed, re-cleaned x 3 before finally I had a clear mote free screen to look at.

Why there should be dust motes on the surface of the CCD is a worry....
(I've had the ASI 174 for a few years now, and never had similar issues - any dust was easily removed from the front of the protective glass by air blow)
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Starry Jack
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Re: How to locate the Dust Bunnies

Post by Starry Jack » Tue Nov 05, 2019 1:36 am

I can't wait to attack the bunnies! Thanks all for the suggestions. Merlin, thanks for the extended narrative. You've pointed out several experiences I have very similar.
Explore Scientific 152mm f6.5 achromat
Aeries D-ERF
Quark Chromosphere f27 native, (f14 when focal reduced)
Mallincam .5x focal reducer (large format)
ZWO174 (IMX249 chip 5um)
Huge Sense of Adventure Viewing Creation

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