Arp157
Galaxy in Pisces
About
In Pisces, about 105 million light-years away, two spiral galaxies are merging as NGC 520. Arp listed it among disturbed galaxies with interior absorption. Its brightness in infrared and radio matches the Antennae, and it is sometimes called the Flying Ghost.
Imaging tips
- Roughly 4′ long, so it is too small to frame by focal length alone: use a long focal length and a fine pixel scale.
- A dark dust lane separates the two components, and the main one is seen edge-on, so broadband data will be needed to show the lane.
- Faint for its size at 23 mag/arcsec²; one imager used 8 frames of 6 minutes at 1600 mm with a sky-glow filter.
- Best in September and October; it peaks near 44° altitude from 50°N.
Facts
- Size
- 4′ × 3′
- Magnitude
- 11.7
- Coordinates
- RA 1h 24.6m, Dec +3° 48′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Sep, Oct
- Peak altitude
- 44° from 50°N, 59° from 35°N