SBN

NEAR Data Archive
 
Multi-Spectral Imager (MSI)

This page provides direct links to volumes containing final versions of PDS-formatted data.

The following topics will aid your search through the NEAR Data Archive:

A note from SBN about dark frames and 0-ms exposures for MSI

For the Eros orbital phase of the archive, image frames as well as dark frames and 0-ms exposures have TARGET_NAME set to EROS in the raw data labels; processed dark exposures are also included in the calibrated data sets. This can cause confusion because the dark and 0-ms exposures are identified as Eros images yet appear to be ''bad'' exposures because of the idiosyncrasies of the MSI camera.

Many MSI sequences were designed such that each image taken by the MSI camera was immediately followed by a 0-ms exposure to correct MSI camera idiosyncrasies. Also the camera was operated near room temperature so there was a significant amount of dark current generated during typical exposure durations. For this reason dark exposures of a duration equal to the usual exposure durations were often taken as a usual component of a sequence and, when viewed, appear to be nearly identical to the 0-ms exposures. Two methods of obtaining dark exposures were often used: (1) closing the shutter during the dark exposure or (2) opening the shutter during the exposure while pointing to ''dark sky''.

It appears both techinques were used on several MSI sequences, such as ''seq9_30_xreg'' which was performed on day of year 2000-205. In this particular sequence, the first eight exposures (m0139720804f4 through m0139723433f4, including their associated 0-ms exposures) appear to have been done with the shutter closed, and then the next six exposures (m0139723596f4 through m0139724413f4) appear to have been done with the shutter opened, but with the MSI camera pointed away from the illuminated part of Eros by some small angle. The fifteenth exposure (m0139724574f4) appears to be the first exposure that picked up a small amount of the illuminated surface of Eros.

Level 1b

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Level 2 Calibrated Data

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Level 3 Data Products

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