astroplan.plots.plot_airmass(targets, observer, time, ax=None, style_kwargs=None, style_sheet=None, brightness_shading=False, altitude_yaxis=False, min_airmass=1.0, min_region=None, max_airmass=3.0, max_region=None, use_local_tz=False)[source]#

Plots airmass as a function of time for a given target.

If a Axes object already exists, an additional airmass plot will be “stacked” on it. Otherwise, creates a new Axes object and plots airmass on top of that.

When a scalar Time object is passed in (e.g., Time('2000-1-1')), the resulting plot will use a 24-hour window centered on the time indicated, with airmass sampled at regular intervals throughout. However, the user can control the exact number and frequency of airmass calculations used by passing in a non-scalar Time object. For instance, Time(['2000-1-1 23:00:00', '2000-1-1 23:30:00']) will result in a plot with only two airmass measurements.

For examples with plots, visit the documentation of Time Dependent Plots.

targetslist of FixedTarget objects

The celestial bodies of interest. If a single object is passed it will be converted to a list.


The person, telescope, observatory, etc. doing the observing.


If scalar (e.g., Time('2000-1-1')), will result in plotting target airmasses once an hour over a 24-hour window. If non-scalar (e.g., Time(['2000-1-1']), [Time('2000-1-1')], Time(['2000-1-1', '2000-1-2'])), will result in plotting data at the exact times specified.

axAxes or None, optional.

The Axes object to be drawn on. If None, uses the current Axes.

style_kwargsdict or None, optional.

A dictionary of keywords passed into plot_date to set plotting styles.

style_sheetdict or None (optional)

matplotlib style sheet to use. To see available style sheets in astroplan, print astroplan.plots.available_style_sheets. Defaults to the light theme.


Shade background of plot to scale roughly with sky brightness. Dark shading signifies times when the sun is below the horizon. Default is False.


Add alternative y-axis on the right side of the figure with target altitude. Default is False.


Lower limit of y-axis airmass range in the plot. Default is 1.0.


Upper limit of y-axis airmass range in the plot. Default is 3.0.


If set, defines an interval between min_airmass and min_region that will be shaded. Default is None.


If set, defines an interval between max_airmass and max_region that will be shaded. Default is None.


If the time is specified in a local timezone, the time will be plotted in that timezone.


An Axes object with added airmass vs. time plot.


y-axis is inverted and shows airmasses between 1.0 and 3.0 by default. If user wishes to change these, use ax.<set attribute> before drawing or saving plot: