HET Observability & Feasibility in the Era of HETDEX

Version 1 (circa 2017)

This program enables a PI to determine the calendar dates, and the times on those nights, when the PI's targets can be observed. This program takes into consideration lunar position (up or down) when the track is available, track length, and the type of twilight cutoff to use (18 deg for dark, 12 deg for bright). It also has some knowledge of when HETDEX targets can be observed and thus takes this into consideration when the moon is down, even for targets that have no Lunar Preference.

It does not output nights when no track is available, nor does it output tracks when the moon interferes with (being present in excess of the constraint) enough of the track that the requested visit cannot be completed. If the moon interferes part-time but the requested visit can be completed, then the track will be output but showing the constrained track length. It does, however, output nights (labeled in green) when the object could be observed but when it likely will not due to HETDEX observing.

Enter the RA, Dec, exposure time, setup time, lunar phase, requested period, your host institution, seeing and transparency limits below and hit the submit button. Note: dark time is considered to be moon below the horizon and after 18 degree twilight.

If you are not familiar with these criteria try looking at the HET Phase II Criteria or The General HET performance pages.

NOTE: Round your RA and Dec values to the nearest second (i.e., do not give decimal values on seconds) to improve accuracy

RA DEC Exposure Time   Setup Time   Lunar Preference   Observing Period   Institution   Seeing Limit   Transparency
h:m:s or h m s d:m:s or d m s seconds seconds YY-P arc seconds