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| Joint Astronomy Centre |
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During the RxH3 maps of 1 January 2002, used for the adjustment of 1 February, the air temperature was about -0.5C. In the movie , made by Fred Baas, there seems to be a correlation between the presence of strong sidelobes (similar to the ones at 17 and 18 February) and relatively high ambient temperatures. The sidelobes disappear again at higher temperatures. We hope that the system of temperature sensors in the dish can be reactivated soon again, and to make series of surface maps with RxH3 to see if we see systematic changes in the dish. I calculated the fraction of the power in the different areas of the beam are for two of these maps. The beam at 450 micron is about 8.5 arcsec (is bit elliptical and is not constant). Mars' size of 2.6 arcsec broadens this to 9.0 arcsec. The power (arbitrary units) within radii of 4.5" (HPBW), 9.0" (main beam), 18" (main beam plus extended wings), 36" (everything including rings) for a 'good' day (11 February) and a 'bad' day (17 February). The values are:
SCUBA Beammaps of Mars at 450 micron. | |||||||||||||||||||||||||||||||||||||
