Arp91
Galaxy in Serpens
About
Two spiral galaxies in Serpens, NGC 5953 and NGC 5954, lie about 78 million light-years away and interact; Arp filed them under spirals that have big, bright companions. NGC 5953 has an active nucleus and a ring of intense star formation around its core, and the encounter has distorted NGC 5954.
Imaging tips
- NGC 5953 measures only about 1.35′ × 1.16′, so the pair is too small to frame: use a long focal length and a fine pixel scale.
- Faint at 22.9 mag/arcsec², so plan many hours of broadband data.
- One imager spent 3 h in LRGB (90 min of luminance, 30 min per colour) in a 40′ field that also held NGC 5951.
- Another imager's short run of 4 × 10 min luminance and 2 × 10 min per colour was held back by 3.5″ seeing, and the framing had clipped NGC 5951.
- Best in May; it peaks near 55° altitude from 50°N.
Facts
- Size
- 3′ × 2′
- Magnitude
- 12.3
- Coordinates
- RA 15h 34.6m, Dec +15° 12′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- May
- Peak altitude
- 55° from 50°N, 70° from 35°N