HET Observability & Feasibility in the Era of HETDEX

Version 4 (circa 2024, post-HETDEX)

Please note that a bug has been reported in the Track calculator, such that for some coordinates the track-length is incorrectly shortened. If the reported track length seems unreasonably short, change your coordinates by a few arcmin to see if the results change. A list of nominal track lengths as a function of Declination is available at https://hydra.as.utexas.edu/?a=help&h=20. If you encounter this issue, please contact us for further assistance.

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 no longer considers possible conflicts with the HETDEX fields because those Priority 0 GTO programs have been completed.

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.

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