This is from a session with the 105mm AP Traveler and SBIG STL11000M CCD, taken on 09-July-2004 and is from a single image taken at 0.002 seconds.
The June 8th 2004 Venus transit is now behind us and was a real hoot (see MPEG or WMV movie), but one additional obstacle has yet to be overcome... Newton's Rings (sigh!). This is an interference pattern optical equipment may fall victim to when presented with an extreme narrow-band signal.
Interestingly, this camera does not exhibit the problem unless the image covers a sufficiently large enough portion of the detector array, making "clean" medium resolution images (as the one above) possible. Unfortunately, flat-fielding (a technique commonly used to remove gradients or other signal anomalies), does not seem to be a viable solution for correcting the problem, so high-res images are problematic.
The rings are very dynamic in nature: Subtle changes in position, focus, or even the surface features that vary from "seeing" conditions, create changes in the patterns. Moreover, the "seed" signals used to spawn the pattern become smeared as harmonics overlap and splay apart. The animation below is comprise of two diffused images taken moments apart with the focus changed. Note the shifting rings, and the "dust mote" at the pattern's 3 o'clock position (used as a reference point). |
