B103
Dark Nebula in Scutum
About
A dark nebula in Scutum, about 3° west-northwest of the open cluster M11. It carries the Lynds number LDN 497 and the top opacity class, 6. Sources disagree on its size, from a few arcminutes to about a degree.
Imaging tips
- Dark nebulae call for broadband imaging, since the cloud is recorded as a gap in the star field.
- Lynds gives it opacity class 6, the darkest on his scale, and one imager found the background still read zero in every frame after a normal stretch.
- Sources give very different sizes, so check the whole field before choosing a focal length; a small round dark cloud, LDN 495, lies to one side of it.
- One imager used 4 × 10 min of luminance and 2 × 10 min per colour channel on a 14-inch f/10 scope.
- Best around June and July; it peaks near 33° altitude from 50°N.
Facts
- Size
- 5′ × 4′
- Magnitude
- —
- Coordinates
- RA 18h 39.2m, Dec −6° 37′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jun, Jul
- Peak altitude
- 33° from 50°N, 48° from 35°N