LROC Experiment Data Record Narrow Angle Camera (EDRNAC)
EDRNAC – Experiment Data Record Narrow Angle Camera
Instrument:PDS Data Set ID: LRO-L-LROC-2-EDR-V1.0
For more information about LROC EDR products, see the EDR Product SIS.
For more information about all LROC products, see the LROC Archive Volume SIS.
The Lunar Reconnaissance Orbiter Camera (LROC) Experiment Data Record Narrow Angle Camera (EDRNAC) data product is a NAC panchromatic image corresponding to a single observation (either full resolution or summed), with Digital Number (DN) counts in 8-bit format, companded from 12-bit in the instrument. The image data consists of one series of contiguous lines up to 52,224 lines with 5,000 samples in full resolution mode, or 104,448 lines with 5,000 samples in 2x cross-track summation mode.
The image file is composed first of the even pixels from each line (with a 20 byte CTX heritage header every 1 MB) and padded to a 1 MB boundary, followed by the odd pixels in the same style. The EDR file generation process extracts the odd and even pixels, interleaving them to reconstruct original scan lines. If compression was enabled at image acquisition, the data stream is first de-compressed before the interleaving is performed. Information from the meta-file, housekeeping, and the SOC database are combined to generate the PDS label with the binary data to compose the EDR file.
Specifications for the Color WAC are in the table below.
| NAC-L | NAC-R |
FOV | 2.8502° | 2.8412° |
IFOV | 10.0042 μrad | 9.9764 μrad |
Image scale at 50 km altitude | 0.5 m/pixel | |
Maximum image size at 50 km altitude | 2.49 x 26 km | 2.48 x 26.1 km |
f/# (Ritchey-Chretien) | 3.577 | 3.590 |
Effective focal length | 699.62 ± 0.08 mm | 701.57 ± 0.09 mm |
Distortion coefficient | 0.0000181 ± 0.0000005 | 0.0000183 ± 0.0000005 |
Optical center location | sample 2548 ± 8 | sample 2568 ± 8 |
Primary mirror diameter | 198 mm | |
MTF (Nyquist) | 0.23 | |
Gain | 90.5 ± 2.6 e-/DN | 92.5 ± 1.5 e-/DN |
Noise | 101 ± 7 e- | 97 ± 2 e- |
Detector fullwell | 334,000 ± 31,000 e- | 352,000 ± 4100 e- |
SNR (400-750 nm) | > 52 | > 49 |
Detector digitization | 12-bit, encoded to 8-bits | |
Lossless compression ratio | 1.7:1 | |
Structure + baffle | Graphite-cyanate composite | |
Detector | Kodak KLI-5001G | |
Pixel format | 1 x 5,064* | |
Analog/digital converter | Honeywell ADC9225 | |
FPGA | Actel RT54SX32-S | |
Voltage | 28 ± 7V DC | |
Peak power | 9.3 W | |
Orbit average power | 6.4 W | |
Mass (both NACs) | 16.4 kg | |
Volume (length x diameter) | 118 cm x 27 cm (incl. radiator) |
*Of the 5064 pixels, 39 masked pixels on the right and 21 masked pixels on the left are used for dark reference.
LROC EDRNAC products have the following file names:
tnnnnnnnnnaE.IMG
where:
t = target
M = Moon
E = Earth
C = calibration
S = star
nnnnnnnnn = 9-digit Mission Elapsed Time of acquisition (with a single digit for partition which denotes a reset of the MET)
a = single character denoting the instrument
R = right NAC
L = left NAC
In ODE, EDRNAC products have the following product IDs:
TNNNNNNNNNAE