Hemisphere:  Southern  ·  Constellation: Antlia (Ant)  ·  Contains:  NGC 3095  ·  NGC 3100  ·  NGC3095  ·  NGC3100  ·  NGC3103
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NGC 3100 and NGC 3095—Galaxy Pair in  Antlia, 


            Russ Carpenter
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NGC 3100 and NGC 3095—Galaxy Pair in Antlia

Technical card

Dates:Feb. 18, 2021

Frames: 14x600"

Integration: 2.3 hours

Avg. Moon age: 6.24 days

Avg. Moon phase: 38.01%

Astrometry.net job: 4251712

RA center: 10h 0' 21"

DEC center: -31° 35' 37"

Pixel scale: 0.956 arcsec/pixel

Orientation: 89.456 degrees

Field radius: 0.250 degrees

Resolution: 1397x1261

Data source: Amateur hosting facility

Remote source: ChileScope


I believe this is the is the first time this pair has been imaged and published by an amateur.

NGC 3100 and NGC 3095 are actually part of a four-part arc of peculiar galaxies. These two are generally categorized as a non-interacting pair. It is not known whether they are a physical pair or are merely optically paired.

NGC 3100 (upper left) is classified as a weakly barred lenticular galaxy. However, careful study has shown that the galaxy has weak asymmetric spiral arms in the outer disk, which might make it analogous to “late-type” spiral galaxies. You can faintly detect the spiral arms in this image. The image also shows dust lanes and a tiny companion galaxy. All in all, a complex and interesting example of a galaxy midway between the ellipticals and spirals.

NGC 3095 (lower right) is classified as an (Sc) spiral, in which a galaxy is relatively bulgeless and the arms are patchy. In this image you can faintly see HII regions.

The Catalog of Southern Peculiar Galaxies and Associations, by Halton Arp and Barry Madore classifies NGC 3100 and 3095 as a peculiar galaxies, because they meet the requirements of category 24 (close pairs and triples).

This pair is difficult to image, because the angular sizes are small. NGC 3100 is only 1.9 arcmin and NGC 2097 is 1.6 arcmin.

Tech Notes for ASA 500/3.6:
ASA Newtonian, 500 mm aperture, 1900mm focal length, F3.6
FLI Proline 16803, 9 mm pixel, 4096 X 4096
ASA DDM85 equatorial mount
Processing with PixInsight, StarTools, and Affinity Photo


Sky plot

Sky plot


NGC 3100 and NGC 3095—Galaxy Pair in  Antlia, 


            Russ Carpenter