Saturday, October 29, 2011


M103 from VAO, Webster, NY
© Billy Vazquez 2011
A young open cluster in the constellation Cassiopeia. But how young is young, that is the question?  The age of this open cluster was estimated to be around 16 million years at a distance of 2900 parsec (Sanner et al., 1999).    The Solar System is roughly 4.5 billion years old.  If we use the age of our solar system and compare it to the stars in this cluster we come to the conclusion that the cluster is younger by 3 orders of magnitude.

M103 from VAO, Webster, NY
© Billy Vazquez 2011
How do we know which stars in the field of view are part of the cluster?    For that, we study the proper motion of the stars, which is the angular displacement over time with respect to the barycenter of the solar system.  All stars that belong to the cluster will have roughly the same proper motion. This indicates that the stars are gravitationally bound and traverse the Galaxy as a unit.

The images of M103 shown were taken using a Johnson V band filter with VAO's 12" SCT @ f/6.3.  They are 36x60 sec exposures co-added in Maxim DL for a total exposure time of 36 minutes.  The imgages were dark and flat subtracted but no further image processing performed other than the color inversion of the second image.

Tuesday, October 11, 2011

Horsehead Nebula

The Horsehead Nebula also known as Barnard 33 is a dark nebula in the constellation Orion and it is located just south of Alnitak.  This dark nebula is located about 1500 light years away from Earth. The red glow is imparted by ionized hydrogen from nearby star Sigma Orionis.

The image shown was taken at VAO with broadband Johnson BVR filters.  Total exposure time is 55 minutes ( 4x300s on B and V, 3x300s on R filters).   It was further processed in PixInsight for dark subtraction and flat field division.  A median noise reduction algorithm was used with a 3x3 kernel to eliminate most of the chrominance noise.   The telescope used was the 12" inch SCT at f/6.3.   Guiding was done with Metaguide with an 80mm APO refractor and Lumenera Skynix. 

In addition I present to you the unedited out of the telescope combined image of 55 minutes on a single grey channel.  You can see the vignetting of the smaller filters over the larger CCD chip area.  As you would imagine this nebula would look much better over narrowband filters to expose more of the filamentary structure at the edges of the dark nebula.