NGC 1961

[alan4908]

NGC 1961 (aka Arp 184, IC2133) is situated close to the celestial pole and so is visible for most parts of the year from the northern hemisphere. It’s an intermediate spiral galaxy about 200 million light years away with an angular size of 4.6 arc minutes, representing a diameter of 240,000 light years. The galaxy is the central member of a group of nine galaxies known as the NGC 1961 group.

The image of NGC 1961 below shows regions of hot blue stars and large HII regions indicating active star formation. Three faint outward pointing arm structures can also be seen. Although the galaxy appears distorted, there is no obvious evidence of past interactions. However, it is speculated that the galaxy is an intruder into the region, perhaps encountering an object in the distant past, which compressed the gas and dust on one side of the galaxy, leading to the observed distortions. Three supernovae have been observed, the latest in 2021. The image does not show the latest event, (discovered on 5^th August 2021) since the sub-frames where acquired before this time.

Some smaller galaxies are also visible in the image and I’ve annotated these via Pixinsight. I was pleased that some details of these smaller galaxies are visible, in particular PCG17675 (bottom left).

This LRGB image was taken with my Esprit 150 and represents approx 11 hours integration time.

Alan

NGC 1961

NGC 1961 (annotated)

LIGHTS: L:21, R:14, G:16, B:14 x 600s all at -20C.

[MartinB]

Excellent.  There is something very special about seeing small galaxies like this against a large starfield.  I love the 2 faint trails coming from the galaxy

[alan4908]

On 10/11/2021 at 14:21, MartinB said:

Excellent.  There is something very special about seeing small galaxies like this against a large starfield.  I love the 2 faint trails coming from the galaxy

Thanks for the comment Martin.  

I normally go for a cropped images on galaxies to create a greater impact. This time, I opted for a much wider field of view with the starfield processed separately in order to make the stars less distracting.

Alan