LROC Experiment Data Record Narrow Angle Camera (EDRNAC)

EDRNAC – Experiment Data Record Narrow Angle Camera

Instrument:

Lunar Reconnaissance Orbiter Camera

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