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Old 01-04-2013, 10:13 AM
Dazzled by the Cosmos.

Dennis is offline
Join Date: May 2005
Location: Brisbane
Posts: 11,339
Hi Lewis

The high-resolution Lunar and Planetary images you see on IIS are generally taken with webcams using Barlow’s (Powermates) with ‘scopes operating at between F16 and F30 at effective focal lengths of 3 to 5+ metres.

High resolution (as opposed to full disc) Lunar, Solar and Planetary imaging normally makes use of relatively inexpensive webcams rather than DSLRs or the traditional deep sky CCDs such as those from SBIG, Apogee, FLI, Starlight, etc.

Webcams are generally 800x600, 1024x768, 1280x960 and 1600x1200 pixel chips which take movies (AVI’s) of between 1000 and 3000 frames. Software then analyses the say, 3000 frames and based on user-set parameters, selects the sharpest, say 300 to 500 frames and then Aligns, Stacks and Finishes the final combined image (usually a .tiff, .bmp, .fit or .png).

An individual frame usually looks quite noisy and ‘thin” but when several hundred are combined, the final image looks cleaner, less noisy and reveals astonishing detail.

With the 4” Vixen you should be able to use an x2 to x2.5 Barlow/Powermate to obtain sufficient image scale although you will be somewhat limited by the modest aperture, compared to the top Planetary imagers on IIS who use instruments in the 11-16” class.


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