This example demonstrates the orbit calculation for a coronagraphic observation. We want to obtain coronagraphic images of a star in two filters, F250W and F606W. The ETC
has shown that the exposure times adequate for our scientific goals are 5 minutes. in F606W and 30 minutes. in F250W. From the orbit visibility table (see the HST Primer
) we find that at the target declination of 15º the target visibility time is 52 minutes. With CR-SPLIT=2, we thus have to accommodate in that period 35 minutes. of four science exposures grouped in two series. The orbit calculation goes like this:
The derived total used time in the orbit shows that our target can indeed be imaged in the selected filters in one orbit. Since there remains 3 minutes of unused time, we can adjust our exposure times to make full use of the available time.
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