Monthly Archives November 2013

The Evolution of the Andromeda Galaxy

Evolution of Andomeda

While the Andromeda Galaxy (M31) has been evolving for the last 9 Billion years, my tenure as an Astrophotographer has only been evolving for the last 1.5 years.  I got the Astrophotography bug when I first snapped a photo of the Moon back on April 7, 2012.  Fast forward to August 2012 where I took my first deep sky image of the Andromeda Galaxy with my Nikon D7000 DSLR through a Takahahshi Sky90 telescope.  I remember being blown away by being able to “see” light from galaxies millions of light years away.  Ever since then, I possessed the desire to learn everything I can about astro imaging.  After shooting deep sky objects (DSO’s) with a digital camera for a few months, I wanted to learn how to shoot with a CCD (Charge-Couple Device), which is a specialized camera for Astrophotography.  I purchased a used SBIG ST-2000XM CCD with a 5 position filter wheel that had Luminance, Red, Green, Blue, and a Hydrogen Alpha filter in it so I could teach myself techniques to get even more detail out of the DSO’s I was shooting.  After I got over a steep learning curve, I was able to work on one very important principle, which was quality over quantity.  With Astrophotography, you need to invest a great deal of time taking multiple exposures to bring out the detail in the amazing objects that are out in space.  This principle is evident in the 4 images of the Andromeda Galaxy that span 1.25 years of learning how to image objects I can’t see with my own eyes...

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Giving CCD Blooms the One-Two Punch with MaximDL and the NewAstro DeBloomer Plugin

When imaging with a CCD camera with a high quantum efficiency (QE), such as the SBIG ST-10XME with the KAF 3200ME chip, you sometimes have to deal with some very nasty blooms.  Due to the ST-10XME lack of antiblooming gate, light from bright stars overwhelm the full well capacity (electron holding capacity) of the pixels on which they are being collected, resulting in excess electrons spilling over into adjacent pixels.  In other words, the light-gathering pixel exceeds its capacity to hold captured photons which yields stars that have irregular diffraction spikes, as seen in the image below.

Blooming Example Pelican Nebula

Sometimes, the blooming can get so bad that you must take special care to preserve the stars and the detail.  During bloom removal, sometimes the excess electrons can spill over onto other stars and destroy them, ruining your star field.  I use MaximDL’s bloom removal tool but sometimes that tool removes more than just the blooms.  There is also an DeBloomer Plugin for MaximDL created by Ron Wodaski, which contains both automatic and manual tools that remove blooms.  The nice aspect of the DeBloomer plugin is that it performs a batch process on all your images.  I recently learned, while processing subs from M31, that the MaximDL bloom removal tool was not sufficient enough to preserve the stars when the blooms from an adjacent star spilled over onto it.  Here is an example:

Here is a two step process for dealing with these types of blooms while preserving adjacent stars using ...

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