Instrument

Celestron C11 @  F/6.1 (1705 mm)  1.087 arcsec / pixel

Mount

Losmandy G11

Camera

SBIG ST-7 with CFW-8A color wheel

Acquisition Date

8/15/05 & 8/17/05  Near downtown Seattle

Exposure

Lum   180 min  (12 X 15 min)
Red     80 min  (8 x 10, bin 2 x 2)
Green  50 min  (5 x 10, bin 2 x 2)
Blue    45 min  (3 x 15, bin 2  x 2)

Software

CCDSoft, FocusMax, CCDOPS, Sigma Clip (pre beta 11) and PhotoShop CS. The DitherMat was used to dither the luminance layer.

Comment

North is to the top.

Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. This planetary nebula's simple, graceful appearance is thought to be due to perspective -- our view from planet Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star.

The Ring Nebula is about one light-year across and 2,000 light-years away in the northern constellation Lyra.