Odyssey THEMIS VIS Apparent Brightness Record (VISABR)

VISABR – Visible Apparent Brightness Record

Instrument: Thermal Emission Imaging System

PDS Data Set ID: ODY-M-THM-3-VISABR-V1.0 (in data directories odtvb1_****) DOI: 10.17189/1520297

For more information about THEMIS VISABR products, see the Data Set Catalog File.

For more information about all THEMIS products, see the THEMIS Product SIS.

The Thermal Emission Imaging System (THEMIS) Visible Apparent Brightness Record (VISABR) data products contain the apparent brightness data derived from the calibrated visible observations (VISRDRs) as one-band IMAGE files. VISABRs are usually derived from band V-3 (see the table below). If the default band is not available, or significantly corrupt, another band may be used. VISABRs are not projected into any coordinate system, however they do contain some basic geometric parameters in the attached header. The VISABR data values are an 8-bit version of the calibrated radiance, scaled to the minimum and maximum radiance values of each source image.

THEMIS VIS images are acquired in framelets of size 1024 pixels crosstrack by 192 lines downtrack. The number of framelets is determined by the number of bands selected (five available, enumerated in the table below) and the spatial resolution selected (three summing modes available). If spatial summing is not applied, either a single-band, 19-framelet (65.6 km) image or a 5-band, 3-framelet (10.3 km) image can be collected.

THEMIS available visible bands:

Band Numbers	Center (μm)	FWHM* (μm)
V-1	0.425	0.049
V-2	0.540	0.051
V-3	0.654	0.053
V-4	0.749	0.053
V-5	0.860	0.045

*Full-width, Half-maximum

THEMIS VISABR products have the following file names:

VnnnnnsssABR.IMG

where:

nnnnn = 5-digit mission orbit when the image was collected

sss = 3-digit image sequence number indicating the order that images were collected each orbit (001 = first image collected in the nnnnn orbit)

In ODE, VISABR products have the following Product IDs:

VNNNNNSSSABR