Quick Tips for Replanning

Contact iso@ipac.caltech.edu to gain access to you observing program, the PGA, and the time estimators, and information on how to get started.

For LWS, you may use either the PGA or the time estimator to get integration times. To use the time estimator type "lws-te" when logged into your ipac sparc account. The lws-te gives accurate integration times for LWS01 and LWS02 AOTS. Add 180 seconds for source acquisition and 40 seconds for other overheads to the lws-te times. The PGA dedicated time (TDT) and the lws-te times will agree closely and the PGA time is always the more correct total time.

When completing your LWS AOTs in the PGA, enter the AOTs specifying integration times (per wavelength step) and not S/N. If needed, the lws-te will give you the S/N noise you will reach with this integration time. This is more work for the observer, and contradicts former recommendations, we realise. The reason for this advice as followsi: LWS sensitivities are still not very well known. If they are eventually measured to be different ESA does not want to have to ask users to replan their program once again, but instead asks users to live with the new sensitivities within their current planned AOTs.

Input times per grating position that are greater than or equal to 1.2 seconds. The LWS instrument is no longer operated with times less than or equal to 1.2 seconds per grating position and the time estimator will give extremely high S/N when such times are input. Do not use times less than 1.2 seconds per step for programs entered into the PGA or time estimator.

Including off-positions in your program is recommended.

All observations should be conducted with Fast Mode On (Fast = YES)

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Last update: August 1998

Steve Lord -- lord@heaven.ipac.caltech.edu