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: http://www.naic.edu/~emuller/EALFA/pix1.html
Дата изменения: Mon May 17 20:07:00 2004 Дата индексирования: Tue Oct 2 02:45:53 2012 Кодировка: Поисковые слова: рер р р р р р р р р р р р р р |
ALFA - 'dishspot' (pre-cursor for 'leapfrog' mode - we've called it 'dishspot' because it observes a constant range of positions on the dish, we will re-name this eventually....). This mode: 1) Moves to the requested RA and Dec, and remembers the AZ and EL. 2) The telescope tracks a source at sidereal rate, for the user-requested length of time. 3) The telescope moves back to the original AZ and EL, calculates the new RA, and loops back to 2) For proper operation, the current mode needs to predict the slew time to the next point. In theory, this should be accurate to less than 10 seconds Data taken at around midday on the 16th May (the sun generated some problems) 10 positions measured, 300 s each pointing. 4096 channels, 100MHz Bandwidth, centred on 4120 MHz. These data here are for the first polarisation on the first pixel. (there are no real reasons why any other polarisations on any other pixels would be much more or less stable.) For Dishspot: Start time (lst hrs):1.6805090 Finish time (lst hrs):2.6052562 Number of tracks: 10 Time per track (min):5 Total observing time (mins): 55.4848 Total integration time (mins): 50 Mean Slew time for between each step (sec)=32.9088 observing efficiency for dishspot:90% NB: For Regular ononff, Wait 1 min at each new 'off' Total observing time=55.4848+Ntracks observing efficiency for onoff:76% Estimates for leapfrog (expected wait at each new 'on' is MAX 10 sec) total observing time=55.4848+Ntracks*0.6 observing efficiency for leapfrog:81% Efficiency will improve for longer integration times.More info on dishspot: 10 positions measured, 300 s each pointing.
RA (hrs) | Dec(deg) |
1.38993 | 34.4629 |
1.47482 | 34.4674 |
1.55956 | 34.4707 |
1.64392 | 34.4740 |
1.72857 | 34.4767 |
1.81321 | 34.4789 |
1.89806 | 34.4803 |
1.98258 | 34.4808 |
2.06706 | 34.4805 |
2.15136 | 34.4802 |
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