SPOT THE DIFFERENCE: RIMAE SOSIGENES (PART 1)

 

                    Here we see the interior of a vent formation on Rimae Sosigenes an interesting Ina-like formation. What differences can you spot here – if any?

 

 

 

Part of Rimae Sosigenes

 

 

 

                    This month we will switch our attention to an Ina like formation. Ina formations are very geologically young areas, often at the bottom of volcanic craters or vents. We are using high sun angle images on this occasion as they seem to bring out some interesting albedo features present which do not show up at shallow sun angle images with shadows. Expect to find a some strong stereo parallax effect, so when blinking between images, you may see some lateral jumps.

 

                    I find it useful to look for differences between images by loading them into an image processing program, e.g. Adobe Photoshop, into layers, and then blinking between layers. You may note a slight amount of image shift and this is due to stereo parallax between the two images.

 

                    Three suggestions I would like to offer. 1) if the jumping effect from stereo parallax is a problem, then break each image down into smaller tiles, re-register each tile with its temporal pair, then try blinking again. 3) Alternatively if you are blinking between layers, then shift layers laterally around slightly to reduce the parallax effect over specific areas. 3) If some areas of the image are low in contrast or texture, then do a high pass filter, followed by a contrast enhancement – this will bring out more detail.

 

 

  M1134074986RCa.jpgM1195298293LCa.jpg

                    The LROC images used for Spot the Difference are: (Left) M1149381600RC taken on 2014 Mar 13 with: Solar Altitude=76.4°, Solar Azimuth=122°, and an image scale originally of 1.1 m/pixel. (Right) M11952983LC taken on 2015 Aug 27 with: Solar Altitude=76.8°, Solar Azimuth=133°, and an image scale originally at 0.9 m/pixel.

 

 

                    When you have finished please email me (atc @ aber.ac.uk) back one of the images with the locations of where you have noted changes and I will report on these in the next Newsletter of the Lunar Sections of the British Astronomical Association, and the Association of Lunar and Planetary Observers. The deadline for doing this will be 15th November 2016.

 

                    P.S. Please do not be surprised if you find no differences between these two images – the Moon is a pretty inactive place, even on some of the more geologically interesting areas.