Saturday, September 24, 2011

The Dark Horse and The Pipe Nebula

Click HERE to see it at its highest resolution

Astronomers have given the dark areas in the above image two familiar names:  "Dark Horse Nebula" and "Pipe Nebula".  The first one is a side view of a "Dark Horse" with the darkest part being the rump and back leg with the fainter head and forelegs to the right.  Can you see that it has one foreleg raised as if it is prancing among the stars?  The Pipe Nebula consists of the rump of the horse as the bowl of the pipe and the rear leg makes up the pipe stem.  Click HERE to see it in high resolution.

The image below is an annotated version outlining the horse and many labels of various "dark nebulae" in and around the horse. Click HERE to see it in high resolution.  The labels starting with the letter "B" are from the Edward E. Barnard catalog of dark nebulae.  Most of the NGC numbered objects are globular clusters (NGC stands for New General Catalog).  I have also outlined some very faint red emission nebulae.  It is best to view it at high resolution on a large monitor as this is the full resolution of my CCD camera.
Click HERE to see it at its highest resolution

The image was taken with my 70-200mm f/2.8 Canon zoom lens set at 70mm and f/5.  A total of 8 images were taken with each image being 15 minutes of exposure.

Monday, September 12, 2011

Green Comet and Globular Cluster

Click on the image for a larger view
The image above is of Comet Garradd as it went by the globular cluster M71 in the constellation Sagitta back on August 26, 2011.  This is the brightest comet in the sky right now, easily visible with a pair of binoculars, but with a couple of provisions.  You need to view it away from the city lights and you need to know exactly where to look.  Because comets are constantly on the move, you will need a star chart for the evening that you go out into the countryside.  Click here to get some printable star charts for the next 6 months (courtesy of Sky and Telescope magazine) as it heads closer to the sun.  Comet Garradd will be visible for quite a long time, so there should be no excuse of not having enough time to see it.

Are you wondering why the comet is green?  One of the few green objects in the night sky, the color is caused by the Sun's ultraviolet light striking the cyanogen gas surrounding the star-like nucleus of the comet making it glow.  The tail is composed of gas and dust, pushed away from the nucleus, by the pressure of light particles from the sun.

The globular cluster, M71, looks to be fairly close to the comet, but not really.  At the time of the picture, the comet was about 130 million miles away from Earth.  M71 is 13,000 light years away.  To make it easier to compare the difference in distances, lets convert the comets distance in miles to light years.  Light travels 186,000 miles per second.  Dividing 130 million by 186,000 gives about 700 seconds.  Now you can really see the difference:  Light takes about 11.6 minutes to get from the comet to our eyes, but from where M71 is located, it takes light 13,000 years to travel from where it is located.

Technical Data:
  • Date Taken: Aug 26, 2011
  • Location: ASKC Dark Sky Site
  • Telescope: 190mm, f/5.3 Maksutov Newtonian
  • Camera:  Q453 CCD (similar to QHY8)
  • Exposure: 30 minutes (consisting of 15 - 2 minute shots)
  • Calibration: 20 Bias, 20 Flats, 1 Dark
  • AutoGuider: Q-Guider with 50mm Finderscope
  • Mount: Parallax Instruments HD 150C
  • Capture Software: Nebulosity
  • Calibration Software: Nebulosity
  • Final Processing Software: Photoshop CS3

Friday, September 2, 2011

Supernova Erupts in the Pinwheel Galaxy

Click on the Image for a large view
On August 24, the Palomar Observatory discovered a supernova in M101, the Pinwheel Galaxy.  The supernova has been getting brighter every day since its discovery.  I took this picture on the evening of August 30.  The star is brighter than the nucleus of the galaxy, which is composed of millions of stars.  M101 is a large face-on spiral near the Big Dipper with an apparent size of the Moon.  It can just barely be seen with a pair of binoculars from a very dark sky, but now the supernova will be brighter than the galaxy, at least until the explosion dies away in a few days.

Click on the image below to show you a labeled picture pointing out the location of the supernova and a few supergiant star forming areas in the galaxy. Three galaxies near M101 are also labeled.  They are NGC5471, NGC5473 and one that almost looks like a star, PGC49919.  They look smaller than M101 only because they are much further away from us.  M101 is 23 million light years away and 170,000 light years across.  This supernova, designated 2011fe, is being studied by the scientific community.  The early detection, combined with the relative closeness of M101, makes this a spectacular find for professional researchers.  Here's a light curve of magnitude measurements (visual, R, V, and B) that the America Association Variable Star Observers has received.