Object Description: (Thanks to SEDS): M46 was the first object Charles Messier discovered after he had published the first edition of his list (M1-M45). He added this one to his catalog on February 19, 1771, three days after presenting it to the academy, together with three more Messier objects, M47, M48, and M49. The cluster is very rich, with 150 stars of mag 10-13 and probably a total population of over 500. The brightest of these stars are of spectral type A0, and each about 100 times more luminous than the Sun (the brightest is of apparent magnitude 8.7). This indicates an age of about 300 million years. The members are scattered over an angular diameter of about 27, corresponding to a linear extension of 30 light years at the clusters distance of 5,400 light years, and are receding from us at 41.4 km/sec, according to Baade. M46 is classified as of Trumpler type II,2,r. As a special and famous feature which is also obvious in the photograph, a planetary nebula (NGC 2438, also FC 87) appears within the apparent borders of M46. This object appears to lie near the northern fringes of the cluster. However, this nebula is most probably not a true member but is superimposed, or perhaps a passing guest. In this picture, you see M46, NGC2438, and another planetary nebula - PK 231 4.1 Equipment Used: - TAK FSQ - ST-2000XM, CFW-10 - FLI-PDF - TAK EM-400 Exposures: - L 4 x 3mins - R 4 x 3mins - G 5 x 3mins - B 3 x 3mins This was a quick opportunity target, plagued by needing a DEC gear adjustment in my mount. Processing: - Initial calibration, registration, and channel combine in CCDStack - I added in synthetic luminance info from the color channels for a 4/3rds push - Photoshop: - final gradient removal - Noise reduction with NeatImage - star trail reduction - increased star core color saturation