Celestial hemisphere:  Northern  ·  Constellation: Camelopardalis (Cam)  ·  Contains:  NGC 1961  ·  PGC 138826  ·  PGC 17642  ·  PGC 17659  ·  PGC 17675  ·  PGC 17692  ·  TYC4344-1007-1  ·  TYC4344-1026-1  ·  TYC4344-1698-1  ·  TYC4344-1961-1  ·  TYC4344-767-1  ·  TYC4344-801-1  ·  TYC4344-803-1  ·  TYC4344-839-1  ·  TYC4344-879-1  ·  TYC4348-1880-1  ·  TYC4348-25-1  ·  TYC4348-51-1
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NGC 1961 (Arp 184), lowenthalm
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NGC 1961 (Arp 184)

Getting plate-solving status, please wait...
NGC 1961 (Arp 184), lowenthalm
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NGC 1961 (Arp 184)

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Description

This is a fascinating object. Arp 1961 is an 11th magnitude galaxy with a lot of action going on. Two tidal tails, lots of star formation regions an stellar associations, a doubled wide looping arm, and interesting dust cloud features can all be seen here. I captured the wider field with several UGC and PGC galaxies that are all at the same distance, making we wonder which one made a close pass to NGC1961 in the distant past and caused all this disturbance in its structure. I vote for little PGC 17659 just below it, which appears bright and disturbed as well. The other brighter galaxies are 15th magnitude UGC 3342 at bottom center-right, 15th magnitude UGC 3344 at bottom right, and PGC 17642 in the upper right. Besides the tiny 17.7 magnitude blue edge on, PGC 138826, just to the right of PGC 17642, none of the other galaxies in the field are SkySafari 6 Pro's expanded galaxy database.

The quarter moon was raising the sky background brightness level, so I couldn't bring out the two tidal tails very well that you can detect in this image. I had to use a wavelet filter to suppress some of the moon worst induced sky noise. The seeing held well for enough time to capture 18 total minutes worth of data over three 6 minute live-stacks of 3 second exposures, which took more than half an hour because of occasional tracking errors and lots of periods when seeing got worse. I had the FWHM star diameter filter set around 5.5 for of the images I captured, and 6.0 for the third. I lost the fourth image I had intended to take to seeing causing FWHM star diameters to rise above 7 suddenly and never coming back, so there was no point in including its data, since the other images were much crisper.

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NGC 1961 (Arp 184), lowenthalm

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Astrophotography with Dobson