Arp10
Galaxy in Cetus
About
UGC 1775, a ring galaxy in Cetus about 395 million light-years away, seen nearly face-on. Arp listed it among spiral galaxies with split arms. Its nucleus sits off-centre inside a ring of star-forming regions, thought to be the scar of another galaxy passing through its disk.
Imaging tips
- Only about 1.5–2′ across, so it is too small to frame: use a long focal length and a fine pixel scale.
- Faint for its size at 23.6 mag/arcsec², so plan many hours of broadband data.
- The ring is made of star-forming regions, and a fainter outer shell with its own arc of HII regions has been reported, so deep data may show more than the ring.
- Best around October and November; it stays below 46° altitude from 50°N.
Facts
- Size
- 2′ × 2′
- Magnitude
- 13.5
- Coordinates
- RA 2h 18.4m, Dec +5° 39′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Oct, Nov
- Peak altitude
- 46° from 50°N, 61° from 35°N