M102 — Spindle Galaxy
Galaxy in Draco
About
A galaxy whose identity is disputed. Two years after publication its discoverer Méchain withdrew it as a repeat sighting of M101; Wikipedia favours NGC 5866, a lenticular galaxy in Draco nicknamed the Spindle Galaxy, and NASA treats the two as the same. Seen edge-on, it has a thin dark band of dust running through its glowing nucleus.
Imaging tips
- About 5′ × 2′, so it is too small to frame: use a long focal length and a fine pixel scale.
- One 13.8-hour LRGB image from Germany (175 × 2 min luminance) records the thin dust band crossing the nucleus and subtle detail in the dim outskirts.
- A dark-site LRGB set used 10-minute subs (8 each of L, G and B, 12 of R), while 42 × 3 min of luminance alone was taken from a Bortle 8 city to test whether it was possible.
- Surface brightness is 21 mag/arcsec². Best around April and May.
Facts
- Size
- 5′ × 2′
- Magnitude
- 9.9
- Coordinates
- RA 15h 6.5m, Dec +55° 46′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Apr, May
- Peak altitude
- 84° from 50°N, 69° from 35°N