C23 — Silver Sliver Galaxy
Galaxy in Andromeda
About
The Silver Sliver Galaxy, Caldwell 23: an edge-on spiral galaxy in Andromeda, about 27 million light-years away and roughly 130,000 light-years across. A dark dust lane runs along its length, and fainter dust filaments reach into the halo. A supernova, SN 1986J, appeared in it in 1986.
Imaging tips
- About 13′ long and only 3′ thick: 1,860–3,110 mm on APS-C frames it, with the long axis along the frame.
- Faint at 22.3 mag/arcsec², so plan many hours of broadband data. One imager took 15.75 hours of luminance plus one-shot colour; another took 12.5 hours of LRGB.
- Dust filaments extend into the halo, and faint stellar streams surround the disk, so deep, gently stretched data may show more than the lane.
- One imager placed the galaxy in a corner of the frame to include dozens of distant background galaxies.
- Best around October and November; it peaks near 82° altitude from 50°N.
Facts
- Size
- 13′ × 3′
- Magnitude
- 9.7
- Coordinates
- RA 2h 22.6m, Dec +42° 21′
- Framing, APS-C
- 1860–3110 mm
- Framing, full frame
- 2860–4760 mm
- Best months
- Oct, Nov
- Peak altitude
- 82° from 50°N, 83° from 35°N