Planning the usage of Solar System bodies as calibrators in ALMA Cycle 0

There are two things to consider when choosing a Solar System body as a calibrator:

1. its location on the sky with respect to the science target(s)
2. its visibility amplitude for the desired antenna configuration.

To assess item 1, you can use buildMinorPlanetPlot in casa to generate a Gildas script that will plot the elevation vs. LST for Solar System objects and your science target. To assess item 2, you can use my script called au.planetPlots() which calls the predictcomp task available in casa >= 3.4.

Plots for end of Cycle 0

Here are the results for the final 3 months of Cycle 0 observing for Venus, Mars, Ceres, Vesta, Pallas, Juno, Ganymede, Callisto, Titan, Uranus, Neptune:

• October 20, 2012
• November 20, 2012
• December 20, 2012

Plots for Cycle 1

Here are results for the 10 official Solar System calibrators for Cycle 1: Venus, Mars, Ceres, Pallas, Jupiter, Ganymede, Callisto, Titan, Uranus, Neptune. Note that Jupiter is so large that it can only ever be used in Band 3 ACA observations:

• April 1, 2013 (Mars is small, 3.9")
• April 1, 2014 (Mars is near opposition, 15")

Simulated visibility amplitudes of selected planets and minor planets in ALMA Cycle 0

The simulations in the table below are a mixture of plots created by simdata/plotms (which was the only method in the beginning) and predictcomp (which only became available in November 2011). The simdata plots are for a duration of 15 minutes centered on transit (unless otherwise noted), while the predictcomp plots are only 1 second duration at a location somewhere close to transit, but not exactly there.

• 16-page plot of Neptune amplitude at 691 GHz by antenna
• Al's asteroid Excel spreadsheet
• statistics of baseline lengths in ALMA configurations
• As of casa r17017 (beyond the current 3.3 release), the predictcomp task can create these kind of plots, so you no longer have to run simdata and plotms. Just run casapy-test!

mydict = predictcomp(objname='Callisto', epoch='2011-12-01/01:40:00', minfreq='345e9', symb='o', antennalist='alma.cycle0.extended.cfg')

Note: if you get an error: "SEVERE predictcomp coercing to Unicode: need string or buffer, dict found", then exit casa, rm ~/.matplotlib/fontList.cache, and restart casa.

If all you want to know is the object's RA and Dec on a specific date, you can use the planet function of analysisUtils.

Body	Compact configuration				Body	Extended configuration				Body
	Band 9	Band 7	Band 6	Band 3		Band 9	Band 7	Band 6	Band 3
Callisto					Callisto					Callisto
Ceres					Ceres					Ceres
Juno					Juno					Juno
Mars					Mars					Mars
Neptune	at transit, and at hour angle = -4 hours				Neptune					Neptune
Pallas					Pallas					Pallas
Titan					Titan					Titan
Uranus					Uranus					Uranus
Vesta					Vesta					Vesta

Elevation vs. LST and UT

15-Oct-2011
01-Nov-2011
15-Nov-2011

Test

Body	alma.cycle0.extended.cfg
	100GHz	230GHz	345GHz	690GHz
Callisto

-- ToddHunter - 2011-09-19