# Reference/API¶

## astroplan Package¶

astroplan is an open source (BSD licensed) observation planning package for astronomers that can help you plan for everything but the clouds.

It is an in-development Astropy affiliated package that seeks to make your life as an observational astronomer a little less infuriating.

### Functions¶

 add_site(site_name, location) Add a site to the list of available observatories. download_IERS_A([show_progress]) Download and cache the IERS Bulletin A table. get_IERS_A_or_workaround() Get the cached IERS Bulletin A table if one exists. get_moon(time, location[, pressure]) Position of the Earth’s moon. get_site(site_name) Return an EarthLocation object for known observatory. get_site_names([full_list]) Get list of names of observatories for use with get_site. is_always_observable(constraints, observer, ...) Are the targets always observable throughout time_range given is_observable(constraints, observer, targets) Are the targets observable during time_range given constraints in observability_table(constraints, observer, ...) Creates a table with information about observablity for all the targets over the requeisted time_range, given the constraints in constraints_list for observer. test([package, test_path, args, plugins, ...]) Run the tests using py.test. time_grid_from_range(time_range[, ...]) Get linearly-spaced sequence of times.

### Classes¶

 AirmassConstraint([max, min]) Constrain the airmass of a target. AltitudeConstraint([min, max]) Constrain the altitude of the target. AstroplanWarning Superclass for warnings used by astroplan AtNightConstraint([max_solar_altitude, ...]) Constrain the Sun to be below horizon. Constraint Abstract class for objects defining observational constraints. FixedTarget(coord[, name]) Coordinates and metadata for an object that is “fixed” with respect to the celestial sphere. LocalTimeConstraint([min, max]) Constrain the observable hours. MoonIlluminationConstraint([min, max]) Constrain the fractional illumination of the Earth’s moon. MoonSeparationConstraint([min, max]) Constrain the distance between the Earth’s moon and some targets. NonFixedTarget([name, ra, dec, marker]) Placeholder for future function. Observer([location, timezone, name, ...]) A container class for information about an observer’s location and environment. OldEarthOrientationDataWarning Using old Earth rotation data from IERS PlotBelowHorizonWarning Warning for when something is hidden on a plot because it’s below the horizon PlotWarning Warnings dealing with the plotting aspects of astroplan SunSeparationConstraint([min, max]) Constrain the distance between the Sun and some targets. Target([name, ra, dec, marker]) Abstract base class for target objects. TargetAlwaysUpWarning Target is circumpolar TargetNeverUpWarning Target never rises above horizon

## astroplan.plots Package¶

astroplan.plots contains functions for making plots of commonly-used quantities in observation planning (e.g., airmass vs. time), using astroplan and Matplotlib.

### Functions¶

 plot_airmass(target, observer, time[, ax, ...]) Plots airmass as a function of time for a given target. plot_parallactic(target, observer, time[, ...]) Plots parallactic angle as a function of time for a given target. plot_sky(target, observer, time[, ax, ...]) Plots target positions in the sky with respect to the observer’s location.