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Lawrence Saturn Occultation - labeled

Identification of Features in LPOD Saturn Occultation Image


This image is posted in response to a question about the identification of the features in a photo of the Moon's southeastern limb as it appeared on the Lunar Photo of the Day for March 5, 2007:




The underlying image was taken by Peter Lawrence of Selsey, UK. This is a composite of two LTVT frames labeled with the official IAU names of all features exceeding 75 km in diameter. The faint gray circles indicate the official diameters.


This image of identical scale to the LPOD image, and can be placed over it in any photo processing software that permits "layers" (some cropping/alignment will be required to make it match). Saturn is not visible because LTVT reconstructs the image using only those pixels in the original image that correspond to the lunar longitudes and latitudes appearing in the scene. Since LTVT is not concerned with intensities in the sky it does not look up any image information at those points.


The calibration data used was:


Photo Date/time : 2007 March 02 at 03:00 UT

Observer Location : Lon = -0.8 Lat = + 50.7 Elev : 20 m

Ref. Pt. 1 : Lon=4.337/Lat=-69.341 (Curtius C) at pixel (766, 254)

Ref. Pt. 2 : Lon=56.030/Lat=-51.512 (Watt K) at pixel (106, 673)


Using these data, the observed features appear quite close to the positions expected from the 1994 ULCN. The feature positions plotted here are of somewhat lower precision, and taken from the IAU list maintained by the United States Geological Survey at:




The freeware LTVT software is available from:




Those using that software and the above calibration can zoom in and identify any of the smaller features that have official IAU designations. Showing them here would have resulted in too much clutter.




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Uploaded on March 5, 2007