M67: This is a nicely aging open cluster in the constellation Cancer, and one of the most widely studied. Since the stars in an open cluster typically all form at the same time, the massive blue stars will evolve and leave the main sequence first. This leaves a majority of dimmer, redder, main sequence stars, and a few red giants from the more massive stars as they end their lives. Interestingly, this cluster also contains numerous, anomalous "blue stragglers", whose origins are not fully understood. More info: http://en.wikipedia.org/wiki/Messier_67
Right Ascension: 8 h 51.4m
Declination: 11° 49'
Apparent Magnitude: 6.1
Date: April 2010
Telescope: Meade 16" Schmidt Cassegrain with f6.3 reducer
Camera: SBIG ST-10XE
Guiding: Meade 5" refractor/DSI Pro/PHD
Exposure: 15x2 minutes RVB.
The camera was at -30C
Processing Notes: Image reduction and alignment was done using CCDStack. Subframes were stacked in Sigma Beta, and the three color channels were combined with a ratio of (1:2:4) and saved as a TIFF(data) file in AstroArt. Photoshop was used to stretch and sharpen the image, and Carboni actions "Enhance Star Color" and "Make Stars Smaller" were applied.
Links to images of this object on other sites:
Additional Comments: This was the second try in a week for M67. The first image, here http://www.fortlewis.edu/observatory/image_detail.asp?ID=183 was just a target if opportunity used to focus RGB filters. This image was taken using the RVB filters in order to get photometric filter transfer functions and measure atmospheric extinction. This time guiding was turned on. Data taken by Chris Hardrick and Bill Fellman. Image processing by Charles Hakes.