Arp319 — Stephan's Quintet
Galaxy in Pegasus
About
Stephan's Quintet, five galaxies in Pegasus, first noticed in 1877 by Édouard Stephan. Four form a real group, lying between about 210 and 340 million light-years out; the fifth, NGC 7320, is a foreground galaxy about 39 million light-years away. Arp listed it as Arp 319, under "Groups of galaxies".
Imaging tips
- Too small to frame: use a long focal length and a fine pixel scale.
- Very faint at 24.3 mag/arcsec², so plan long broadband integration; one imager logged 8 hours 30 minutes on a C11, another 380 minutes of luminance plus 930 minutes of colour.
- NGC 7320 sits in the frame but is a foreground galaxy, not part of the physical group.
- Best around August and September; it peaks near 74° altitude from 50°N.
Facts
- Size
- 4′ × 3′
- Magnitude
- 13.0
- Coordinates
- RA 22h 35.9m, Dec +33° 57′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Aug, Sep
- Peak altitude
- 74° from 50°N, 89° from 35°N