Saturday, April 21, 2007

re: Markarian's Chain and Autoguiding


Will miracles never cease? After a long run of cloudy and blustery nights, including a 9" snow and several rainshowers, April 19 offered a calm and clear night.
Several "advances" (relatively speaking) were made. For one, I was finally able to field test the autoguiding setup (PHD Guiding + Meade DSI). With a minimal amount of tweaking the CG5 mount was tracking like never before! My compliments to Craig Stark, who distributes PHD Guiding as freeware. (Click on the photo for a larger image.)
The second step ahead was tweaking the focus using ImagesPlus rather than my own eye. Eric Jacob and Mike Reid had noted that the focus was soft in the previous images. And finally I increased the exposure from 60 seconds to 180 seconds. (Acquisition and processing details below.)
The photo has a good bit but not all of Markarian's chain included. The two bright galaxies near the middle of the photo are M84 (on the right) and M86. M87 is in the lower left. Altogether I can count 22 galaxies in the image -- all part of the Virgo Supercluster. If the opportunity presents itself I plan on capturing the missing Messier objects (M88-M91, M99, and M58) and then taking a shot at my first mosaic image.
Abundant information on Markarian's chain can be found online. Here's a link to a fabulous astroimage by Karel Teuwen of Markarian's Chain.
Clear skies.
Max
Image Acquisition and Processing Data
Camera control with ImagesPlus 2.82 using the Xti and Borg f/4 astrograph on the CG5 mount
Autoguiding with C102, PHD and Meade DSI
18 subs at 3 min/ISO1600
(54 total minutes)
Eight darks at 1 min/ISO 1600
No bias or flats
Converted, calibrated, aligned, stacked, digitally developed (settings 0, 1.05, 4500, soft sharpen) in IP
Resized in PS CS2
Astronomy Tools star reduction action, enhance deep sky object action, and increase star color action
Converted for the web in PS CS2

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