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Something odd in M51 image

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#1 mdavister

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Posted 07 June 2020 - 02:04 AM

So I was getting some data on M51 for Goofi's monthly challenge and noticed an odd artifact on one of the stars. It is on the top of the image, it appears that there is a blue material being ejected from the star. I checked some other images people have taken, and it does not show up there at all. I thought it might be something to do with the micro lenses on the camera, but it is not symmetric. Is this an optical aberration, or something real?

 

Camera is a QHY294C, scope is a Meade 130mm APO.

 

Forgive the brevity of the message its 3am and I'm tired. smile.gif

Attached Thumbnails

  • M51_G2400_N10_300S_1_300s_2_CFW0_RGB_VNG_SMALL.jpg
  • StarZoomed.jpg

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#2 Huangdi

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Posted 07 June 2020 - 02:40 AM

Looks like a reflection to me..
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#3 Tapio

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Posted 07 June 2020 - 03:18 AM

Agree, reflection.

Do you have a reducer or a filter in use ?


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#4 WadeH237

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Posted 07 June 2020 - 09:19 AM

Are you using Hyperstar by chance?  This looks like a Schmidt ghost, which is a specific kind of reflection artifact.  They are common when shooting at F/2 with an SCT and a bright star in or near the field.

 

If that's the case, then you should consider a strong dither between subs.  That will move the reflection around from sub to sub, and then you can use stacking to reject them.



#5 elmiko

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Posted 07 June 2020 - 10:01 AM

Looks almost like a drop of dew or something on one of the elements in the imaging train.



#6 mdavister

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Posted 07 June 2020 - 08:38 PM

With regards to the oddity, I was leaning towards reflection, but I'm not sure what the source would be. Of course there is the optical window of the camera, but my filter was about 4" away from the sensor (long nose piece extension). I am running dew heaters on the main scope, and it was a dry for Pennsylvania night. Only saw some dew on the power cable running in the grass when I went to tear everything down for the night.

 

I'm still learning the ropes with the CMOS camera. The previous CCD camera behaved a bit different.




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