Emission Nebula in Cygnus
The Crescent Nebula is a peculiar one, because it is typically listed as an emission nebula, but it has several characteristics that are similar to those of planetary nebulae. In long exposures where its dimmer portions can be seen, the crescent fills out and becomes an oval. The nebula consists of illuminated gases that have come from the bright star in its center (an old star classified as a Wolf-Rayet star), and they are being illuminated by energy from that star.
| Magnitude | 7.4 |
| Apparent Size | 18' x 12' |
| Distance (light yrs) | 5,000 |
| Right Ascension | 20:12.7 |
| Declination | +38 21 |
| Field of View | 29' x 22' |
Image details: Exposure times of 48 minutes luminance and 15 minutes each of red, green, and blue, taken with an SBIG ST-8300M imager and a 14" Meade LX850 telescope at f/6.
July 2015