This series of blogs, which I proposed to write frequently late last year fell by the wayside sometime in Oct. Since it is the new year, I figured I should resurrect this sleeping project of mine. The problem I have had with this blog was the poor quality images I was getting (i.e. grainy with heaps of electronic noise). This came from mostly imaging with my Meade DSI I C, which has no active cooling and has a much smaller chip than my new CCD cam, the Orion StarShoot Deep Space Imager II. I am hoping to get a series of test shots this coming weekend (i.e. tomorrow) and see how we go from there. Should this camera work well, I am planning to do more suburban imaging as that is where I spend most of my time observing anyways when I cannot get out to the darker Malibu or Pinos skies, which during good months is a measly two times.
So yes starting this week, look out for this new series of blogs. This will alternate with my "Blast from the Past" blogs (only two more to go). This new "Imaging from the Burbs" series will be short update blogs to showcase what I have accomplished with my meager astro-imaging setup (Celestron NexStar 102GT {or with the Celestron Travelscope 70}, Orion StarShoot Deep Space Imager II {in place of my most used Meade DSI I C}, 0.5x focal reducer and Orion Sky Glow light pollution filter) from the suburbs of west Los Angeles and to show what can be accomplished with minimal equipment and light polluted skies. My immediate plans are to improve my astrophotography by shooting heaps more and getting even more intimately familliar with the software, post processing and image stacking. I may also try imaging with different different filters, such as the DGM Optic's NPB (Narrow Pass Band) filter or even the Celestron/Baader OIII filter to stack with images taken with just the broadband filters.
Due to the sky conditions (mostly still from where I live as opposed to slightly windy to super windy conditions at Malibu and Pinos), I found that I could push the exposures as long as 30 seconds without having the stars trail in my images using the 102 GT on alt az GOTO NexStar Mount. Most times I stick between 15 and 21 seconds and this seems to be the sweet spot. For brighter starlike objects such as stars and smaller planetary nebulae, I tend to go even lower and use between 8 and 11 seconds exposure, and then take multiple images to stack. Exposing it for too long washes out the nice colors of these smaller planetaries. For the wider field Celestron 70 Travelscope, I find I can go as high as 45 seconds, so that is even better.
Also for now, I find myself taking anywhere between just three to six images. I know this is not ideal for fainter fare, but Autostar Envisage seems to start making weird calls with anything above that. With the new CCD cam, I hope to take more stacks and see if that improves the signal to noise ratio, since it uses a different capture software, the much used MaxIm DL.
Someday I hope to image with a larger scope and possibly with a GOTO EQ mount, but for now this is the best I can do with what equipment I have. I have shot quite a number of objects of all classes, open clusters, globular clusters, planetaries, emission and reflection nebulae, supernova remnants and galaxies, so I am slowly coming to terms with what works best for different classes of objects.
One of the most important steps in getting the most out of your images is in post-processing. Photoshop is a very powerful tool and I am also still learning the intricacies of getting the most data out of my images. I generally used levels to determine the darkest and lightest points in the images, then use curves to stretch the histogram, before using the dropper tool to darken the background. Also with most of the longer exposures, I find I generally have to use an averaged dark frames for dark subtraction to remove electronic noise. Still having issues with hot colored pixels (hopefully this gets solved with the Orion CCD....if this is the case, I will try to use the Orion for suburban imaging).
So till I get some preliminary data...this is it from me for this blog...
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