Trumpler 5, Cr 105, in Monoceros

click the image for a larger view, or HERE for the index


I just love this little obscure, or rather overshadowed, cluster.  It isn't often separated from its famous friends, but I think it worthy.  I suppressed the red background glow a bit as it is mostly without details ... just red, which distracts imho.

TR 5, Collinder 105, is located in the star clouds about one degree west of the cone nebula in Monoceros and is about 7 arc minutes in diameter with visual magnitude of 10.9.   Wide fields of the cone/sMon region often show it.  Consensus is that it is about 3 Gy old, 2.8 kpc distant, and in the thin disk of the milky way, although trailing the majority by a bit... it is one of the most massive clusters in the milky way.  

The best source of data on TR5 (that I could find) comes in an article from 2003, filed in the Cornell library at <>  (that is, if you need some good reading to put you to sleep <G>).   I have attached some pertinent excerpts to the bottom of this page, if you are wont to dig into the tech data ... I got into it when I went looking for the carbon star, identified as V493 Mon, located about 2.5'  below center.  After some time of doubt, it appears to be a member of the cluster... (The earlier papers are dreary to say the least!)  V493 is a variable carbon star about mag 13 or 14.  It stands out in the bigger versions.


Explore Scientific 127mm, f7.5, ED apo with carbon fiber tube. Mounted piggyback on a Meade LX200 classic 12-inch SCT


Canon XT/350d modified with Baader type 1 filter by Hap Griffin


17 five minute sub exposures at iso 800, captured RAW. I used iso 800 in an effort ot retain more range in star color.


Modified 10 x 50 finder scope with Meade DSI pro I controlled by PHD Guiding from Stark Labs


Images acquired, calibrated, stacked, and color corrected in Nebulosity 2.2.7 from Stark Labs. Further processing in Photoshop CS3. November 26, 2011