Aug 152016
 

NGC 6791 is an open star cluster in the constellation Lyra. Discovered in 1853, it is unusual in that there are three distinct populations of stars in the group. Along with a group of 8 billion year old normal stars there is a group of white dwarfs with a 6 billion year age and a group of white dwarfs with a 4 billion year age. This is contrary to the classic definition of open star clusters such that the stars of such a group are all born from the same molecular cloud and all have the same general age. Needless to say, this cluster has astronomers questioning their understanding of cluster formation and is heavily studied.
 
NGC 6791 was one of the few deep sky objects included in the field of view (FOV) of the Kepler spacecraft during its primary science mission.

(NGC 6791) [C: 56x60s]

(NGC 6791) [C: 56x60s]


Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

 Posted by at 23:59
Jan 022016
 

The observatory upgrade proceeds, but the outside temperature has delayed cutting new floor panels. The current plan is to try again over the next couple of days. If the conditions don’t improve I will restore the previous floor/wiring configuration to bring the PTO back online as soon as possible and watch for the next favorable opportunity to resume the floor task. I am anxious to observe the shadow of minor planet (1424) Sundmania as it passes across the panhandle on the 12th of January.

In the meantime I am processing a backlog of imagery.

This image was taken on the 14th of December. NGC 2266 is a compact open cluster discovered by William Herschel in 1785 in the constellation of Gemini. It is relatively old for an open cluster and has an estimated age of 1 billion years. The cluster’s distance has been estimated as 2.6 kpc (8485 ly).

NGC 2266 [C:58x30s]

NGC 2266 [C:58x30s]

Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

 Posted by at 15:01
Dec 202014
 

 
Once again the PTO archive provides this image. Often misidentified as the Little Dipper, The Pleiades (M-45) is an asterism in the constellation Taurus.

M 45
Since this cluster of stars is very bright and a very prominent group in the sky, it is featured in many of the world’s cultures’ literature and folklore.

  • To the Greeks the stars represent the ‘Seven Sisters’. These were the seven daughters of Atlas (a Titan) and Pleione (a sea-nymph).
  • To several Native American tribes the cluster was seven wives who husbands rejected them because they constantly ate onions. The wives ran away but once they were gone, the husbands relented. So now, the husbands (the Hyades cluster) forever chase after their wives (the Pleiades cluster).
  • The Japanese word for the cluster is “Subaru” and a stylized representation of the cluster is used as the emblem on the cars of the company of the same name.
  • The Bible mentions them 3 times in Amos 5:8; Job 9:9; and Job 38:31; for example:

Amos 5:8 – Seek him that maketh the seven stars and Orion…

This open star cluster is ‘only’ 100 million years old or so. But, compared to the estimated 4.5 billion year old Sun, this cluster is just an youngster. Analysis of the cluster shows an estimated 1,000 stars as members and it has an estimated distance of 444 Ly. The group does not have enough mass to remain gravitationally bound for long and is destined to slowly drift apart. At one time the nebulosity that is apparent in the image was thought to be the remains of the cloud of gas and dust that the stars were born in, but it is now known that the cloud is unrelated and the stars just happen to be passing through it.

Although the cluster is a small group, it is larger than my camera/telescope field of view. The image above is a mosaic of 4 different exposures combined to capture the entire asterism.

 Posted by at 09:17
Dec 282012
 

Located only 26′ southwest of its bigger, brighter neighbor, M 35, this open star cluster is often overlooked by observers.  First discovered by William Herschel in 1784 and originally thought to be a globular cluster, several studies have shown it to be an old open star cluster some 11,750 LY distant.  It is located on the extreme western edge of the constellation Gemini.

(NGC 2158) [C:41x30s]

This image is a stack of 41 thirty second images taken on the evening of the 21st of December. The short bright vertical streak on the right side of the image is the asteroid (21) Lutetia.  The minor planet is traveling from top to bottom (E to W).

 Posted by at 22:17