Recently I took a picture of the Hercules Galaxy Cluster (Abell 2151).
Full Frame:
http://www.astrovox.gr/forum/album_pic.php?pic_id=18032
Telescope: Celestron CGE & C9.25" f/6.3 @ 1480mm
CCD : SBIG ST-2000XCM @ -10 Celsius.
Exposure: 17 x 900 sec with AO-8 @ 10Hz.
Image Scale : 1 arcsec / pixel
When you compare the above photo with the one from the STScI Digitized Sky Survey you can clearly see the proper
motion of a couple of stars (which is quite interesting by itself) but in the STScI frame, galaxy PGC57073 has a peculiar
structure that its completely missing in my photo. Could this be some kind of artifact in the STScI frame?
Have you ever seen anything similar?
Below is an animated GIF of the cropped region. The red arrow points to the structure in question.
![Image](http://s5.postimg.org/wk2q8dg2v/Abell_2151_anim_cropped_750.gif)
PGC57073
Animation in Full Resolution:
http://s5.postimg.org/wk2q8dg2v/Abell_2 ... ed_750.gif
Thank you.
George.