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Old 27-04-2010, 03:18 PM
TrevorW
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QHY 8 Dust Motes

I followed the instructions in the manual but notice only after 4 uses there are still quite a few dust motes appearing in images

Anyone else experienced a similar problem and how best to remove

Also noticed my most recent image shows a band along the bottom of the image what would cause this ??

Cheers
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Old 27-04-2010, 04:36 PM
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multiweb (Marc)
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Flat fielding and dithering will get rid of that you know. Are there that big on the sensor that it's becoming a problem?
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Old 27-04-2010, 05:06 PM
TrevorW
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Marc not big just a number of small ones but I would have thought for a new camera there would be a lot less dust motes

Could the line be because I imaged with the Ed80 and probably wouldn't fully illuminate the CCD

Also I assume with flats I'd need to take new ones every imaging session

Cheers
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Old 27-04-2010, 05:16 PM
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multiweb (Marc)
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Quote:
Originally Posted by TrevorW View Post
Marc not big just a number of small ones but I would have thought for a new camera there would be a lot less dust motes

Could the line be because I imaged with the Ed80 and probably wouldn't fully illuminate the CCD

Also I assume with flats I'd need to take new ones every imaging session

Cheers
Doesn't matter how well you clean the stuff, even new, you'll always get a bit of dust somewhere in your imaging train. I wouldn't freak out about the sensor. Dust on the sensor would look very sharp in your pics. Almost black. Ask Theo what product is safe to use on the glass surface. Maybe acetone with a cotton bud?

For the line I'm not sure. Can you post a pic?
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Old 27-04-2010, 05:58 PM
TrevorW
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Hey marc

here is a stacked frame no flats or bias frames

auto levels, colour and contrast only resized and converted to jpeg

and one unprocessed unstacked grayscale single sub converted to a jpeg

line at bottom
Attached Thumbnails
Click for full-size image (1hr 48min stack 18f 3d.jpg)
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Click for full-size image (acetneb-017 single frame.jpg)
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Old 27-04-2010, 06:40 PM
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multiweb (Marc)
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Ha yeah ok... I can see it now. What program are you using to capture? Did this suddenly happen or has it been like that for a while? Maybe it's a readout issue. I don't think it's a problem with the CCD because you can see stars in the line. Defects lines are usually vertical. Have you showed this to Theo?
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Old 27-04-2010, 07:17 PM
TrevorW
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First time didn't happen when using the RC with the same capture software

ie: Maxim

No haven't referred to Theo

Cheers
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Old 27-04-2010, 10:48 PM
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removing dust: flats. But yeah, you need to take new flats whenever you have moved the camera with respect to the OTA. If you image at home, you could just keep the camera attached to the OTA and not have to re-do the flats too often.
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Old 28-04-2010, 09:02 AM
TrevorW
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Thanks Roger no permanent set up that's why I've never nailed drift alignment everything gets put back in their cases after every use
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