Thursday, August 7, 2014

The next thing

So first light was a success, I was able to get a pretty good polar alignment and take some out of focus star images to run through WinRodder. For perspective here is a 1second black and white image of a star field from first light.

The bright star at the bottom of the frame is Vega.

I know what you're asking why would you want to take an image of an out of focus star. Well WinRoddier is software which attempts to reconstruct the wavefront of light coming through the telescope optics from Vega, the result is a reconstruction of the optical aberrations, or optical imperfections, of the mirror. In short this software will tell you if your optics are good, bad or mediocre.

Unfortunately I took images in TIFF format when I needed them in FITS format, the problem is that the software I used to operate the camera saves TIFF images in RBG (Red, Blue, Green) channel format, this results in the exact same data being written into all three channels.  Which lead me to have to go through a round of extracting the color channel data and then running it through WinRoddier.

Only to find that my aberrations were huge, not necessarily because the optics that were sent to me are bad but because I forgot about the first element in my optical system, the sky itself. Air pockets of different density refract light differently, and thus as you take an image the first lenses that light pass through are these air pockets in the sky, now from the above image I was able to measure the seeing, or the ammout of distortion caused by the atmosphere, its 2.68 arcseconds, which is not aweful (>5 arcseconds) but it sure as heck isn't good. (<1.5 arcseconds) The humidity on Monday night was high which probably contributed to the seeing. So now I need an artificial star to test my optics in doors.

Finally the software that I used with my camera is both old, and poorly designed, so I have now taken to working on a piece of software to replace it. But since have always claimed I wanted to write a Open Astronomical Image Processing software solution, now is as good a time as any to start. The code can be found at GitHub (in the Warp_Core1 directory) if anyone is interested in my next steps. It currently uses Visual Studio 2013 to compile.  

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