This sequence was undertaken as part of an experiment to determine if there would be any benefit in working with a larger image size. The camera was direct-coupled to a 3mm Radian eyepiece, which itself yields 400X when used visually with this 1200mm fl, 8" Mak-Newt'. With the afocally mounted camera zoomed to its optical max of 4X, Jupiter's disk is a whopping 680 pixels wide in a 2048 X 1536 field.
81 individual images were made, but the majority (which were done @ 1 second) had a washed-out, low definition appearance. 8 images were shot @ 2seconds, with more intense coloration and improved contrast, but the added time gave the atmosphere more opportunity to smear things around. Only one of the 8 was a "keeper".
The 20 best shots were culled from the 1 second batch and processed with AstroStack, using weighted assignments (bad, average, or good) for each. The resulting image was then itself re-stacked with the single good bright image, the former assigned as an "average" quality and the latter as "good". Io was obtained via PhotoShop by "Apply Image/Blend/Adding" of two images, doubling the signal strength.
The results seem to bear out the wisdom of matching the image scale so as to minimize the exposure time. Also, taking many images and discarding most but reaping a few real gems! My next attempt will be with a more modest image scale and comparably reduced exposure times. Focusing with the InterAct LCD screen is now part of my normal procedure. |
