The two Narrow Angle Cameras (NACs) provide high-resolution (0.5 to 2.0 m/pixel) panchromatic images over a combined 5 km swath. While not designed to image within the Permanently Shadowed Regions (PSR) near the lunar poles, the LROC NACs can obtain useful images with long exposure observations of PSRs at time of maximum secondary illumination. The increased exposure time (20x to 80x) leads to pixel smear and elongated pixels in the along track direction, and thus reduced image resolution compared to typical NAC images (10-40 m/pixel vs. 0.5-2 m/pixel). This may also result in bright saturated pixels outside the PSR. For more information about PSRs and PSR products, refer to [1] or the PSR Atlas. NAC images acquired on consecutive orbits, or occasionally over non-consecutive orbits under very similar lighting conditions (e.g. less than 5 degrees difference in incidence angle and the same sun direction), can be combined to create controlled mosaics. A control network is generated to tie the images to the most accurate ground truth available and a bundle adjustment is performed to correct for pointing errors and image alignment. The images are then map-projected using the GLD100 (WAC derived 100 m/pixel DTM) and LOLA derived crossover corrected ephemeris and mosaicked together into an almost seamless mosaic of the region. A manual linear stretch is performed on images for the final mosaic and it is cropped to the PSR region using a PSR boundary shapefile to create an additional mosaic product. The PSR boundary shapefile is derived from PSR maps modeled from LOLA [2].

PSR Atlas
North PSR Pole Mosaic

[1] Cisneros, E., et al. "Lunar Reconnaissance Orbiter Camera Permanently Shadowed Region Imaging - Atlas and Controlled Mosaics." Lunar and Planetary Science Conference. Vol. 48. 2017. Abstract #2469.

[2] Mazarico, E., et al. "Illumination conditions of the lunar polar regions using LOLA topography." Icarus 211.2 (2011): 1066-1081.

RDR Name NAC_ROI_PSRSYLVNLOA_P823N2917
Site Name Permanently Shadowed Region in Sylvester N
PSR ID NP_823380_2913430
Center Lat 82.3
Center Lon 291.7
Pixel Scale 6.00 m/px
# Images 2
Incidence Low Sun

Images used, in order of layering from front to back:
Image ID Center Lat Center Lon Incidence Pixel Scale
M1119450011L 82.31 292.60 81° 5.99 m/px
M1119450011R 82.38 290.72 81° 5.98 m/px

Permanently Shadowed Region in Sylvester N low-Sun controlled NAC mosaic (A)

Cropped and stretched mosaic (6.00 m/px) (click for more information)