This product is an uncontrolled mosaic of LROC NAC images of the North pole of 
the Moon, projected in Polar Stereographic with a scale of 1 m/px at the pole. 
The mosaic has a latitude range of 85.5 degrees to 90 degrees and is stored as 
40 map tiles.

The tiles are in latitudinal bands of 1 degrees, except for the polar tiles, 
which cover 1.5 degrees of latitude. There are four tiles in the first band 
(88.5 degrees to 90 degrees latitude), eight in the second (87.5 degrees to 
88.5 degrees latitude), twelve in the third (86.5 degrees to 87.5 degrees 
latitude), and sixteen in the fourth (85.5 degrees to 86.5 degrees latitude).

Due to the tilt of the Moon's spin axis (1.54 degrees), some regions near the 
poles are in permanent shadow while other nearby regions remain illuminated for 
the majority of the year. This subtle tilt causes lighting changes from 
lunation to lunation. The poles are most illuminated at their respective summer 
solstice. Thus images for this NAC north pole mosaic were acquired during the 
northern solstice (2010-01-18 through 2010-06-07), and layered in order of the 
greatest incidence angle and sub-solar latitude closest to the pole.

All NAC images were map projected onto the LOLA polar DEM, sampled at 100 m/px,
using the LOLA crossover-corrected ephemeris. All tiles use the same polar 
stereographic projection so they can be combined into a seamless mosaic without 
reprojection. The images were not registered to one another.

Each file is named with the following pattern:
 NAC_POLE_NORTH_P###N????
where:
 P indicates the map projection (P=Polar Stereographic)
 ###N indicates the center latitude in 1/10th degrees North (N)
 ???? indicates the center longitude in 1/10th degrees East

When citing this product, use the following reference:
Wagner, R. V., Speyerer, E. J., Robinson, M. S., & LROC Team. (2015). 
    New Mosaicked Data Products from the LROC Team. In Lunar and Planetary 
    Science Conference (Vol. 46, abstract #1473).
    https://www.hou.usra.edu/meetings/lpsc2015/pdf/1473.pdf

Low-resolution 8-bit browse products in PNG format for this product, along with
full-resolution 8-bit GeoTIFFs, are available at the following location, with
names matching those of the full-resolution IMG files:
http://lroc.sese.asu.edu/data/LRO-L-LROC-5-RDR-V1.0/LROLRC_2001/EXTRAS/BROWSE/NAC_POLE/NAC_POLE_NORTH/

For more information on LROC Reduced Data Records (RDRs), please refer to the
Software Interface Specification (SIS):
http://lroc.sese.asu.edu/data/LRO-L-LROC-5-RDR-V1.0/LROLRC_2001/DOCUMENT/RDRSIS.PDF