starplot.MapPlot

Map plots are general purpose maps of the sky. They're not dependent on an observer's location, but they are dependent on time if you want to include the planets and/or the moon in the plot.

There are four supported projections for map plots:

• Mercator (the default)
• Stereographic North
• Stereographic South
• Mollweide

starplot.MapPlot(projection, ra_min, ra_max, dec_min, dec_max, dt=None, limiting_magnitude=6.0, limiting_magnitude_labels=6.0, ephemeris='de421_2001.bsp', style=MAP_BASE, resolution=2048, hide_colliding_labels=True, adjust_text=False, rasterize_stars=False, star_catalog=stars.StarCatalog.HIPPARCOS, dso_types=dsos.DEFAULT_DSO_TYPES, *args, **kwargs)

Creates a new map plot.

Parameters:

• projection (Projection) –

  Projection of the map

• ra_min (float) –

  Minimum right ascension (hours) of the map

• ra_max (float) –

  Maximum right ascension (hours) of the map

• dec_min (float) –

  Minimum declination (degrees) of the map

• dec_max (float) –

  Maximum declination (degrees) of the map

• dt (datetime, default: None ) –

  Date/time to use for star/planet positions, (must be timezone-aware). Default = current UTC time.

• limiting_magnitude (float, default: 6.0 ) –

  Limiting magnitude of stars to plot

• limiting_magnitude_labels (float, default: 6.0 ) –

  Limiting magnitude of stars to label on the plot

• ephemeris (str, default: 'de421_2001.bsp' ) –

  Ephemeris to use for calculating planet positions (see Skyfield's documentation for details)

• style (PlotStyle, default: MAP_BASE ) –

  Styling for the plot (colors, sizes, fonts, etc)

• resolution (int, default: 2048 ) –

  Size (in pixels) of largest dimension of the map

• hide_colliding_labels (bool, default: True ) –

  If True, then labels will not be plotted if they collide with another existing label

• adjust_text (bool, default: False ) –

  If True, then the labels will be adjusted to avoid overlapping

• rasterize_stars (bool, default: False ) –

  If True, then the stars will be rasterized when plotted, which can speed up exporting to SVG and reduce the file size but with a loss of image quality

• star_catalog (StarCatalog, default: HIPPARCOS ) –

  The catalog of stars to use: "hipparcos" or "tycho-1" -- Hipparcos is the default and has about 10x less stars than Tycho-1 but will also plot much faster

• dso_types (list[DsoType], default: DEFAULT_DSO_TYPES ) –

  List of Deep Sky Objects (DSOs) types that will be plotted

Returns:

• MapPlot –

  A new instance of a MapPlot

adjust_labels()

Adjust all the labels to avoid overlapping.

close_fig()

Closes the underlying matplotlib figure.

draw_reticle(ra, dec, size=6, color='red')

Plots a basic reticle on the map.

Parameters:

• ra (float) –

  Right ascension of the reticle's center

• dec (float) –

  Declination of the reticle's center

• size (int, default: 6 ) –

  Relative size of the reticle

• color (str, default: 'red' ) –

  Color of the reticle (Matplotlib format)

export(filename, format='png', padding=0, **kwargs)

Exports the plot to an image file.

Parameters:

• filename (str) –

  Filename of exported file

• format (str, default: 'png' ) –

  Format of file: "png" or "svg"

• padding (float, default: 0 ) –

  Padding (in inches) around the image

• **kwargs –

  Any keyword arguments to pass through to matplotlib's savefig method

in_bounds(ra, dec)

Determine if a coordinate is within the bounds of the plot.

Parameters:

• ra (float) –

  Right ascension

• dec (float) –

  Declination

Returns:

• bool –

  True if the coordinate is in bounds, otherwise False

plot_bino_fov(ra, dec, fov, magnification, style=DEFAULT_FOV_STYLE)

Draws a circle representing the field of view for binoculars.

Parameters:

• ra (float) –

  Right ascension of the center of view

• dec (float) –

  Declination of the center of view

• fov (float) –

  field of view (degrees) of the binoculars

• magnification (float) –

  magnification of the binoculars

• style (PolygonStyle, default: DEFAULT_FOV_STYLE ) –

  style of the polygon

plot_circle(center, radius_degrees, style, num_pts=100)

Plots a circle

Parameters:

• center (tuple) –

  Center of circle (ra, dec)

• radius_degrees (float) –

  Radius of circle (degrees)

• style (PolygonStyle) –

  Style of circle

• num_pts (int, default: 100 ) –

  Number of points to calculate for the circle polygon

plot_ellipse(center, height_degrees, width_degrees, style, angle=0, num_pts=100)

Plots an ellipse

Parameters:

• center (tuple) –

  Center of ellipse (ra, dec)

• height_degrees (float) –

  Height of ellipse (degrees)

• width_degrees (float) –

  Width of ellipse (degrees)

• style (PolygonStyle) –

  Style of ellipse

• angle (float, default: 0 ) –

  Angle of rotation clockwise (degrees)

• num_pts (int, default: 100 ) –

  Number of points to calculate for the ellipse polygon

plot_object(obj)

Plots an object (see SkyObject for details).

Parameters:

• obj (SkyObject) –

  The object to plot

plot_polygon(points, style)

Plots a polygon of points

Parameters:

• points (list) –

  List of polygon points [(ra, dec), ...]

• style (PolygonStyle) –

  Style of polygon

plot_rectangle(center, height_degrees, width_degrees, style, angle=0, *args, **kwargs)

Plots a rectangle

Parameters:

• center (tuple) –

  Center of rectangle (ra, dec)

• height_degrees (float) –

  Height of rectangle (degrees)

• width_degrees (float) –

  Width of rectangle (degrees)

• angle (float, default: 0 ) –

  Angle of rotation clockwise (degrees)

• style (PolygonStyle) –

  Style of rectangle

plot_scope_fov(ra, dec, scope_focal_length, eyepiece_focal_length, eyepiece_fov, style=DEFAULT_FOV_STYLE)

Draws a circle representing the field of view for a telescope and eyepiece.

Parameters:

• ra (float) –

  Right ascension of the center of view

• dec (float) –

  Declination of the center of view

• scope_focal_length (float) –

  focal length (mm) of the scope

• eyepiece_focal_length (float) –

  focal length (mm) of the eyepiece

• eyepiece_fov (float) –

  field of view (degrees) of the eyepiece

• style (PolygonStyle, default: DEFAULT_FOV_STYLE ) –

  style of the polygon

refresh_legend()

Redraws the legend.

This is useful if you want to include objects in the legend that were plotted AFTER creating the plot (via plot_object)

starplot.Projection

Supported projections for MapPlots

MERCATOR = 'mercator' class-attribute instance-attribute

Good for declinations between -70 and 70, but distorts objects near the poles

MOLLWEIDE = 'mollweide' class-attribute instance-attribute

Good for showing the entire celestial sphere in one plot

STEREO_NORTH = 'stereo_north' class-attribute instance-attribute

Good for objects near the north celestial pole, but distorts objects near the mid declinations

STEREO_SOUTH = 'stereo_south' class-attribute instance-attribute

Good for objects near the south celestial pole, but distorts objects near the mid declinations

starplot.map.DEFAULT_FOV_STYLE = PolygonStyle(fill=False, edge_color='red', line_style='dashed', edge_width=4, zorder=1000) module-attribute

Default style for plotting scope and bino views