Old 23-04-2012, 01:41 PM
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Rod Burgess

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Question Wierd Shot

I took this shot of M8 ealy Sunday morning between the hours of 02:20 & 03:27 AEST. The shot is compiled of 40 x 30 second LRGB exposures.
I was using a 150mm f/5 Reflector with a Meade DSI II Colour CCD camera. Is this space junk? or what, definately not a meteor shower?
Anybody with any ideas as to what I have captured here.
The below shot is a sum of all shots, it also appears in a Sigma Clip combine but not a SD Mask combine.
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Old 24-04-2012, 07:35 PM
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Rod Burgess

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OOPS again

Looks like I found the cause of the funny shot. Dust on the secondary mirror.......I made the entire capture into an AVI and what was happening was very obvious. The Scope must have been knocked of alignment slightly and I was getting drift as respect to M8 (top right to bottom left)
It was how Maxim DL stacked the images to align them that caused the dust particles to streak across the field of view, a lttle bit of wind hitting the scope to cause the wiggles.
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Old 24-04-2012, 11:18 PM
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Moon (James)
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That's one very psychedelic shot!

Dust on the secondary would be really out of focus, so it's probably something else.
You should manually look at each sub image. To me it looks like one sub has trailing, probably caused by a bump - You said it only happens with 2/3 stacking algorithms and this is a good hint - some stacking methods can mask this type of problem by rejecting bad data, which is the same way you can get rid of satellites trails too btw.

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Old 24-04-2012, 11:23 PM
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Tandum (Robin)
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Looks like a sub wasn't tracking properly and it's showing perodic error
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Old 25-04-2012, 12:55 AM
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ballaratdragons (Ken)

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Yep, I've had this lovely result before.

It is a capture of the scope moving. All the wiggly lines are stars.
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Old 25-04-2012, 12:28 PM
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Rod Burgess

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Yes it seems like stars but unsure, I checked the camera and the scope optics and both are spotless. I made an avi of just the Luminous frames, bit hard to tell what has happened.
Here is the link below that I uploaded to my site so you can check out what is going on. all LRGB frames have this.
http://www.rodroger.com/images/astronomy/M8 clip.avi

If these are stars, which they probably are, where are the bright ones that are in the shot? Why are they in every exposure, you can see them in every seperate LRGB exposure. I was using Meades Auotstar Envisage to capture the shots, maybe it had a hicup some how when grabbing or subtracting the darks.....?

Last edited by rodroger; 25-04-2012 at 12:38 PM. Reason: More info needed to be added
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Old 25-04-2012, 06:21 PM
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scagman (John)
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Hi Rod, could it be caused by dead/stuck/faulty pixels. I had the same cam and got similar but a lot short things in my image which I think are stuck pixels.
10 x 5min exp.
NG 127mm refractor.

Just another thought.

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Old 26-04-2012, 05:07 PM
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bmitchell82 (Brendan)
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Ill put my hand up for they are stars, and the squiggles are your PE wind or the like. Why do i think this, you have pure blue stars in spots purple lines in others.
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