M46


Click Image for full size view
Warning: Full size images can be very large
By
Catalog
Obj Type
Location
Date Taken:
Smoot
Messier 46
Star cluster
Mayhill, NM
12-07-2007
Description

Messier 46 (M46, NGC 2437) 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 cluster's 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.

Note that a colorful planetary nebula (NGC 2438, also FC 87) appears within the apparent borders of M46

Technical Details
Exposure Time:
RGB with 30 minutes per color
Camera:
SBIG STL-11000M
Telescope:
RCOS 16 inch f/8.7 Ritchey-Chretien
Mount:
Software Bisque Paramount ME
© 2019 Smoot
Used with permission, No reproduction of these images are permitted without written approval from Smoot.