Phobos sessions

Description

High resolution observation (~0.7 km / pixel) during fly-by. Circular orbit synchronized on Phobos (Phobos quasi-synchroneous orbit), the spacecraft is depointed to follow Phobos.
The telemetry file contains two sessions: first a single-pixel track, then an image-cube. Intermediate calibration sessions include several series of 10 spectra of Phobos, that are not calibrated (see this page for details).

 

Observations

Name Date Spectra   Window size Phase angle Solar Meridian Ls Mars-Sun dist (au)
PHObos window 25/03 600 24 x 25 28°-31.5° ~160° 17.5° 1.599
Phobos track (PhT), uncalibrated 25/03 298 298 x 1 15°-21° ~160° 17.5° 1.599

 

Special corrections

Single-pixel track:

  • The average phase angle is 20°, Phobos distance is about 190 km, with Mars on the background.
  • All spectra are acquired on Phobos.
  • Dark current file: fond1403.dg2
  • Gain = 2
  • Focal plane temperature = -77.4 °C
  • The Phobos track is contamined by Marsshine, and is not calibrated.
  • Location of pixels on Phobos is not accurately determined.

Image-cube:

  • The average phase angle is 30°, Phobos distance is about 220 km.
  • About 400 spectra are acquired on Phobos, the other 200 on the dark sky.
  • Dark current file: fond2103.dg3
  • Gain = 3
  • Focal plane temperature = -76.7 °C
  • A special processing is applied to register spectral channels (spatial convolution applied by program CorPho.for to minimize registration discrepancies). Registered/convolved data are provided in files PHOEVEN.RES and PHOODD.RES.
  • Four different coordinate files are provided for this session, to plot either maps or camera-view of the image cube. See PHO_COOR.LBL.
  • Observations are performed at gain 3, but are recalibrated: the uncertainty on gain 3 coefficients does not affect this session.

Files

  Telemetry file Edited data (track) Edited data (image-cube) Calibrated data (image-cube) Coordinates image-cube)
Data file PHOB2503.DAT PHTEVEN.EDT
PHTODD.EDT
PHOEVEN.EDT
PHOODD.EDT
PHOEVEN.RES
PHOODD.RES
PHOEVEN.CAL
PHOODD.CAL
PHO_COOR.DAT
PHO_SCOR.DAT
PHO_SCRN.DAT
PIXLOC.CTR
Label RAW_DATA.LBL PHT_EDT.LBL PHO_EDT.LBL
PHO_RES.LBL
PHO_CAL.LBL PHO_COOR.LBL

 

 

Back to contents / Retour au sommaire