Sunday, September 25, 2011

Double Cluster - NGC 869

NGC 869 in Perseus
©Billy Vazquez @ VAO Webster, NY  9/18/2011
NGC 869 in BW
©Billy Vazquez @ VAO Webster, NY  9/18/2011
The Double Cluster are two open clusters in the constellation Perseus.  The one in the images is NGC 869 at a distance of 7600 light years.   It is believed it is about 13 million years old and it is also known as Cadwell 14.

The images were taken with the 12" SCT at f/6.3 with Astrodon Johnson VBR filters.   Total exposure time was 2.5 hours.  I am still using the Orion Parsec camera.  In this instance I binned the image 2x2.

The mass of NGC 869 is estimated at 3700 solar masses with a color excess B-V of 0.56.  Both clusters are near identical in age, distance and  redenning.  Whether the double cluster is the core of the Per OB1 association is still in debate according to Slesnick et al. 2002.

Thursday, September 15, 2011

M36 - An Open Cluster in Auriga

©Billy Vazquez @ VAO Webster, NY  9/11/2011
The open cluster M36 was discovered by Giovanni Batista Hodierna, an Italian astronomer of the 17th century. Rediscovered by Charles Messier as entry number 36 in his catalog.

©Billy Vazquez @ VAO Webster, NY  9/11/2011
The cluster is rather young with an approximate age of 25 million years and it is roughly at a distance at 4,000 light years.  The brightest stars on the image are of spectral type B.

This means these stars have temperatures that reach up to 33,000 K.  These stars are also very fast spinners.   You might ask how do we know they are fast rotators?   The key is on a technique called spectroscopy which breaks the light of the stars into its different emission and absorption lines and from the width of these lines we can tell the rotation speed.  

The image was taken from my observatory and it is a LRGB color combined image.  3 x 5 minutes exposures over each Johnson filter and 15 minutes exposure over a luminance (IR Blocking) filter. 

Sunday, September 4, 2011

Orion's Nebula - M42

M42 - Orion's Nebula
©Billy Vazquez @ VAO (Webster, NY) 9/4/2011

I remember when I did my first "Big Upgrade" to a Dobsonian 10" reflector and I took the "Little Monster", that is how I playfully called it, outside for a first light.  It was a cold winter night but that is no deter for an avid astronomer.   Orion's Belt was clearly visible to the naked eye and I remember the beautiful images of Orion Nebula's  from my old dusty books.  Not to mention all the beautiful Hubble images on the Internet.

Well, some years have gone by since that day  outside where Orion's Nebula was a fuzzy blob on the eye piece. Both technology and my equipment have advanced quite a bit since then. I present to you last night's Orion's Nebula.  An RGB composite of 7x20 sec exposures over each filter (Bessel V, Bessel B and H-Alpha).  Post processed with MaximDL.   The scope is my 12" LX200 ACF SCT at  f/6.3.

Orion's Nebula is a stellar nursery 1,344 light years away.  It is the closest star formation region to our Sun. And its span is about 24 light years across. The 4 stars at the center that are barely resolved are part of the Trapezium open cluster.  M42 is an astrophotogpaher challenging target as its stars are much brighter than the surrounding nebulosity.