GeminiFocus 2016 Year in Review | Page 41

2016B Observing Tool
The 2016B Gemini Observing Tool ( OT ) was released on June 3 , 2016 . Installers for Mac , Linux , and Windows may be downloaded from the OT webpage . This version of the OT has several significant improvements to make preparing Gemini observations easier .
The first big change is the removal of the button to trigger the Automatic Guide Star ( AGS ) search . Guide star queries are now performed automatically in the background whenever users create or modify observations . This new feature works with all instruments and will update the guide star whenever an observation , or observing conditions , are updated . It will also automatically select the best guide star when the nighttime observer updates the time of non-sidereal or parallactic angle observations . If you don ’ t like the automatically chosen guide star you may use the Catalog Query Tool ( new in 2016A ) to manually select your preferred one . Manually selected guide stars ( and guide stars from previous semesters ) are displayed in a “ Manual ” target group , and the auto-guide star system will not modify them .
The second big change is an overhaul of non-sidereal target support , which is fundamentally different in the 2016B OT . The 2016A OT handled non-sidereal targets using a mix of data — Minor Planet Center and Jet Propulsion Laboratory ( JPL ) minor planet orbital elements , a selectable list of the eight major planets , and manually generated ephemerides — which can be confusing and cause errors when preparing observations .
The 2016B OT supports all non-sidereal targets using automatically generated and updated ephemerides from JPL HORIZONS . When a user creates an observation the OT will download a low (~ 6-hour sampling ) resolution ephemeris covering the entire semester for planning purposes . For accurate visualization in the Position Editor and optimal guide star selection , this is augmented by ~ 5-minute resolution data for the scheduled night observation . The Observing Database independently keeps track of active non-sidereal observations and downloads high ( 1-minute sampling ) resolution ephemerides the day before an observation might be scheduled .
New plotting capabilities in the Position Editor accompany these infrastructure changes , displaying the path of non-sidereal targets throughout the semester . The red line in Figure 16 shows the orbit of Titan as seen from Maunakea in March-April 2016 . The yellow circle in the center marks the start of an observation , and the green line segment shows the position of Titan during the scheduled observation .
There were many smaller improvements and bug-fixes too numerous to mention . Please see the OT Release Notes for more details , and for more news on upcoming software changes please follow the Gemini Science Software Blog .
Figure 16 . Position Editor showing the position of Saturn ’ s moon Titan ( green line ) with the start of the observation indicated by the yellow circle .
January 2017 | 2016 Year in Review GeminiFocus
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