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Use Cases
ejeschke edited this page Jun 13, 2015
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Observation exercise with Skyfield.
This use case is for the casual or amateur astronomer, who is simply interested in where certain objects will be in the sky (alt/az) over the course of the night.
- Local longitude/latitude.
- Lists of target names and RA/Dec if applicable.
- Local start/end times (assumes that user wants positions updated once an hour).
- Alt/az coordinates during time window for each object.
- Would be nice to have: skychart showing path of objects over course of night.
- targets--large arrays of targets, culled from observation blocks of dozens to low hundreds of proposals
- times for nights spanning a semester, scheduling all nights--only one target will be observed at a time, and targets may be repeated
- Each OB also specifies an exposure time, PA, minimum acceptable air mass, target-moon separation (in deg), moon phase, (other constraints such as seeing, sky transparency, filter, etc. are also present, but assumed checked by added constraints objects)
- Observatory parameters
- Target positions in az/el at the checked times, along with additional info such as parallactic angle, separation from moon
- Assume scheduling is customized, built on top of constraints checks
- Scheduling main goal is to complete observation of top-ranked programs, secondarily to maximize the efficiency of observation by minimizing excessive filter exchanges, long slews
- (Like Brett) Super extra bonus points if instrument rotator angle can be tracked/limited and also dome rotation +/- deg
- Desirable: plots and charts of target vs. airmass/moon altitude, slew map
- A particular sky PA that fits two (or more) stars in a long slit
- Accepts ephemerides for transiting planets including an epoch, period and transit duration
- Extra bonus points if instrument delta rotator angle can be tracked/limited (if I stay on this star for 6 hours, how far has my instrument rotated?)
- A list of targets that need to be observed one at a time.
- A particular sky PA, different for each target.
- A particular exposure time (might be different for each target) - can be interpreted as a minimum time, allowing for longer observations if it makes sense.
- Minimum useful observable airmass
- Observatory parameters (minimum altitude, location, time, etc.)
- A particular date (or multiple dates) for the observing run.
- Order and time of observation for each target.
- Should be at the lowest airmass possible.
- Bonus for getting them to be observed such that their sky PA is as close as possible to the parallactic angle.
- Extra bonus points if slew time from target-to-target is minimized.
- Ideally, could be re-calculated on the fly during the night to adapt for changing conditions.
This is very similar to Erik T.'s, with the added annoyance that the stars are pulsating:
- A list of targets that need to be observed one at a time.
- A particular exposure time (might be different for each target) - can be interpreted as a minimum time, allowing for longer observations if it makes sense.
- Minimum useful observable airmass
- Time of maximum amplitude and period for each source
- A range of allowed phases to observe any given star (e.g., 0.1-0.8)
- Observatory parameters (minimum altitude, location, time, etc.)
- A particular date (or multiple dates) for the observing run.
- A catalog of RV standard stars, and the number of RV standards that I would like to observe
- Order and time of observation for each target.
- Should be at the lowest airmass possible.
- Extra bonus points if slew time from target-to-target is minimized.
- RV standards should be spread out over the night and should be close to other targets.