Arp222
Galaxy in Aquarius
About
NGC 7727, a peculiar galaxy in Aquarius about 76 million light-years away. It is the product of two spirals that merged roughly a billion years ago, and its centre holds two nuclei, each with a supermassive black hole, about 1,600 light-years apart. Arp listed it under "Galaxies with amorphous spiral arms".
Imaging tips
- Sources give 4.7 × 3.5′, too small to frame by focal length alone: use a long focal length and a fine pixel scale.
- Faint at 22.9 mag/arcsec². In one imager's 10 shots totalling 6 minutes from a 25 cm scope, a loop on the far eastern side, extending north, was barely visible.
- One imager used 20 luminance frames of 1200 s and 7 frames of 1200 s in each of red, green and blue.
- The small galaxy NGC 7724 lies about 12′ west, nearby rather than in the same field.
- Best around August to October, but it stays below 28° from 50°N and reaches 43° from 35°N.
Facts
- Size
- 4′ × 3′
- Magnitude
- 11.6
- Coordinates
- RA 23h 39.9m, Dec −12° 18′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Aug, Sep, Oct
- Peak altitude
- 28° from 50°N, 43° from 35°N