Smart Basketweaving

Smart basketweaving

A new smart basketweave observing mode that can start and stop anywhere in a lambda depending on a given RA range of the map has been implemented. This mode also keeps a record of which tracks have been observed and can select one that hasn't been done. The new mode eliminates the need to allocate extra observing time to allow for complete lambdas covering areas outside the intended map area. It also eliminates the need for complicated command files to determine start positions and the problem of not being able to restart a basketweave session in case a problem aborted the on-going observation. The new mode has been implemented in CIMA version 3.1 and it is expected that all users of basketweaving will switch to this mode as soon as they have completed any field started with the old basketweaving mode.

The observing menu for the smart basketweaving currently looks like this:

The observer should specify a box on the sky in right ascension and declination and provide a start LST. The start LST should be the LST time when the basketweaving is supposed to start at the start RA. For basketweaving at the meridian, the start LST should be the same as the start RA. It is not necessary to specify a start LST if the basketweave mode is 'True Az/ZA' since this mode only observes at the meridian.

Once the observing parameters have been set up, You should generate a track file by pressing the 'Create one' button and supply a name for the track file as well as a one-line description (which will be shown together with the filename when browsing for track files). The track file contains all the smart basketweaving parameters as well as a list of all the tracks to be observed. When using an already created track file, You should click on the button with the 'Track file' name which will open a browser window. When a file has been selected from the track file browser all the parameter values will be read in from that track file.

The only parameter that is not stored in the track file is the 'Track number'. This can either be set to a specific track to observe or to 'Automatic' in which case, CIMA is free to choose any track that has not yet been observed. The track file is updated by CIMA when a smart basketweave track is observed. It is thus possible to observe a complete map without the need to make any modifications to observing parameters or command files from day to day.

Smart basketweaving can be run either interactively or from a command file. For command file observing, it is necessary to have a pregenerated track file, since that one is going to be used both to provide the observing parameters as well as the list of which tracks have been observed. A typical command file may look like the following example. This example will do the following: automatically select a track that hasn't been observed from the track file baboon.track, make a smart frequency calibration before the smart basketweaving if there is time for it, run the smart basketweaving from the start RA or from the first possible RA if started too late, update the track file and finish with a smart frequency calibration if it wasn't done before the smart basketweaving.

SETUP SMARTFREQ loops=2 secs=10 caltype=hcorcal adjpwr=first newfile=continuous
SETUP SMARTFREQ freqs={1375 1390 1405 1420}
SELECTBASKETTRACK file=baboon.track track=auto mins=5
SMARTBASKET file=baboon.track track=selected
The new commands have the following options:
   file  = name of track file
   track = track number to observe or "auto"
   mins  = time in minutes that SMARTFREQ needs
           (excluding slew time)

   file  = name of track file
   track = track number to observe or "auto" or "selected"
The conditional test RUNPRESFS is true if a SELECTBASKETTRACK has been executed and there is enough time to slew to the start position and perform a smart frequency observation before the start LST of the smart basketweaving is reached. If this is the case, the conditional test RUNPOSTSFS will be false, otherwise it will be true.

The smart basketweave will start observing at the start RA at the start LST. If the start LST has already passed or the start position can't be reached by the telescope in time for the start LST, CIMA will calculate a new LST where it can catch up, and start from there instead. A track can thus be aborted and restarted anywhere.

The source name will be set to 'Track-N' where 'N' is the track number used. The automatically selected track is exported to the CIMA frontend during command file observations, so when opening the observing menu, the 'Track number' menu will not show 'Automatic' but the actual track being observed. Restarting the smart basketweaving either from the observing menu or by restarting it in the command file will force CIMA to continue observing the same track. The latter works if the SMARTBASKET command has been called with track=N or track=selected --- however, if the SMARTBASKET command is called with track=auto, then a new, unobserved track will be selected each time the command file is restarted.

The typical way to select a track is with the SELECTBASKETTRACK command, but track can be set to "selected" even if SELECTBASKETTRACK is not used. In that case, SMARTBASKET will select a track that hasn't been observed so far just like "auto" --- the difference appears if You restart the command file: "selected" will then continue on the already selected track, while "auto" will choose another track that hasn't been observed.

Note though that CIMA will only remember an automatically selected track for as long as CIMA is running. If You have to exit and restart CIMA in the middle of a smart basketweaving session, then that information will be lost and You should manually select the track that CIMA had chosen earlier and run the smart basketweaving interactively from the observing menu --- otherwise CIMA will start on a new track!

The following is an example of a track file created by the options shown in the observing menu figure above:

# CIMA smart basketweave track file   ---   version 1.00
# Description: Test of smart basketweaving
# This is a computer-generated file --- do NOT edit!!!

# Parameters:
#   Start RA         = 230000
#   Stop RA          = 010000
#   Start Dec        = 100000
#   Stop Dec         = 150000
#   Start LST        = 230000
#   Number of tracks = 6
#   Scan time        = 587
#   Turn around time = 13
#   Basketweave mode = traditional
#   Calibration type = hcorcal
#   Calibration time = 3
#   Calibrate when   = twice
#   Winking cal      = off
#   Winking cal type = lcorcal
#   Adjust power     = never
#   Loops per file   = 1

# Tracks:

1 1 -OK----   2008-Sep-08: 23:00:00-00:59:47  (00:19:04-02:18:51)
2 1 -LATE--   2008-Sep-12: 23:12:15-01:00:01  (00:15:16-02:02:59)
3 1 -EARLY-   2008-Sep-11: 23:00:00-00:29:39  (00:07:01-01:36:03)
4 0
5 0
6 1 -OK----   2008-Sep-09: 23:00:00-01:00:00  (00:15:08-02:14:47)

The track lines contains the following information:

The track file is computer generated and should not edited --- with one possible exception: if CIMA has observed a track and You want to redo that track. You can, of course, run smart basketweaving and explicitly specify that track as the one to use, but You can also modify the track file so that the track again will be considered when CIMA is choosing a track automatically. CIMA is only checking the second column (the number of observations) when determining if a track has been observed or not. It is thus enough to reset that number to '0', if You want an already observed track to be available for automatic selection again. You do not need to remove the status flag and the observation data, if You don't want to.

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This page is administered by Prakash Atreya ( patreya (a) naic . edu ) and was last updated on 11 December 2008.