Calibrated Data Record (CDR)













Calibrated Data Record (CDR)

These data cover a wavelength range from the far ultraviolet (115-180 nm) (FUV) through the middle ultraviolet (160-320 nm) (MUV) to visible (250-600 nm) (VIS) wavelengths, with an average spectral resolution of 0.6 nm. The UVVS Calibrated Data Records (CDRs) consist of calibrated data derived from mascs uvvs Experimental Data Records (EDR)

Before the data can be used for scientific analysis, the EDR count rates must be converted to physical units and the data must be transformed into meaningful physical reference systems. Wavelength range and sensitivity of each grating step vary, as documented in the MASCS Calibration Report.

Although the data span Earth, Venus and Mercury fly-bys, UVVS began routine orbital observations of both the dayside and nightside exosphere on March 29, 2011. Altitude profiles for all previously detected neutrals (H, He, Na, K, and Ca ) except for He and K have been measured. The former has no emission features within the UVVS wavelength range (115 - 600 nm), and the latter has only one relatively weak feature.

UVVS also scans for species that are known or are predicted to be present in the surface materials (e.g., Si, Al, S, Mn, Fe, and OH). Targeted sequences during the third through fifth years have been designed to measure the average exosphere content of species that are detected and substantially reduce the detection limits for the rest.


Access to the Calibrated Data

The CDR archive is arranged according to mission phase: Launch (lau), Earth Cruise (eac), Earth Flyby (eaf), Venus 1 & 2 Cruise (vc 1 & 2), Venus 2 Flyby (vf2), Mercury Cruise 1-4 (mc1-4) , Mercury flyby 1-3 (mf1-3) , Mercury Orbit 1-5 (orb, orb2-5). Then by day, which includes UVVS (UV to visible) and VIRS (visible to IR). Within UVVS the data are subdivided according to far UV, mid UV and visible and, within each category, a science and housekeeping file compose an individual data product.


Useful Documents

Useful documents located in the documents directory
UVVS_CDR_DDR_SIS.PDF: The MASCS UVVS CDR/DDR SIS: "MESSENGER MASCS UVVS Calibrated and Derived Data Record Software Interface Specification"

UVVS_VIRS_COMBINED_DDR_SPEC.PDF: The MASCS UVVS/VIRS COMBINED DDR Specification: "MESSENGER MASCS UVVS+VIRS Combined Derived Data Record Specification"

UVVS_EDR2CDR.TXT: Detailed procedures and tables for EDR to CDR calibration.

UVVS_CDR2DDR.TXT: Detailed procedures and tables for CDR to Atmosphere DDR data reduction.

UVVS_CDR2DDR_SUR.TXT: Detailed procedures and tables for CDR to Surface DDR data reduction.

UVVSVIRS_DDR2DDR_COMBINED.TXT: Detailed procedures for UVVS-VIRS DDR to Combined DDR data reduction.

MASCS_CAL_RPT.PDF: The MESSENGER instrument calibration report for MASCS

UVVS_CALIBRATION_CHANGES_PDS7.PDF: "UVVS Calibration Changes for PDS Delivery 7". Describes the need for and method of removing solar background signal in several emission wavelength regions.

UVVS_CALIBRATION_CHANGES_PDS11.PDF: "MESSENGER MASCS UVVS Calibration Update - PDS 11". Describes the UVVS FUV CDR calibration sensitivity update.

UVVS_PROCESSING_UPDATES_PDS16.PDF: "MESSENGER MASCS UVVS Processing Updates - PDS 16". Describes the UVVS CDR and DDR processing updates for PDS delivery 16.

CALCIUM_CHAMBERLAIN_MODELS.PDF: Description of the calcium Chamberlain models in Adobe Acrobat format.



Access to the Calibrated Data

The CDRs are in binary format and each is described by a detached PDS label . Detailed descriptions of the parameters in the label can be found in the label directory.

See the UVVS Calibrated and Derived Data Record Software Interface Specification Document for a detailed description of the instrument and the calibrated data. Also see uvvs_cdr_ds.cat, which provides further information.


Quick Look Indices

Indices for Calibrated data for the Ultraviolet date Specific Mission Phases – Individual files can be selected based on observational parameters and the corresponding URNs submitted below to retrieve the files.



Accessing Binary Files

An IDL tool which translates the CDR binary files is available (See side bar)