# SkyViewClass¶

class astroquery.skyview.SkyViewClass[source]

Attributes Summary

Methods Summary

 get_image_list(position, survey[, …]) Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files. get_images(position, survey[, coordinates, …]) Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files. get_images_async(position, survey[, …]) Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files. Print out a formatted version of the survey dict

Attributes Documentation

URL = 'http://skyview.gsfc.nasa.gov/current/cgi/basicform.pl'
survey_dict

Methods Documentation

get_image_list(position, survey, coordinates=None, projection=None, pixels=None, scaling=None, sampler=None, resolver=None, deedger=None, lut=None, grid=None, gridlabels=None, radius=None, width=None, height=None, cache=True)[source]

Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files.

Note that the files will be downloaded when the generator will be exhausted, i.e. just calling this method alone without iterating over the result won’t issue a connection to the SkyView server.

Parameters
positionstr

Determines the center of the field to be retrieved. Both coordinates (also equatorial ones) and object names are supported. Object names are converted to coordinates via the SIMBAD or NED name resolver. See the reference for more info on the supported syntax for coordinates.

surveystr or list of str

Select data from one or more surveys. The number of surveys determines the number of resulting file downloads. Passing a list with just one string has the same effect as passing this string directly.

coordinatesstr

Choose among common equatorial, galactic and ecliptic coordinate systems ("J2000", "B1950", "Galactic", "E2000", "ICRS") or pass a custom string.

projectionstr

Choose among the map projections (the value in parentheses denotes the string to be passed):

Gnomonic (Tan), default value

good for small regions

Rectangular (Car)

simplest projection

Aitoff (Ait)

Hammer-Aitoff, equal area projection good for all sky maps

Orthographic (Sin)

Projection often used in interferometry

Zenith Equal Area (Zea)

equal area, azimuthal projection

COBE Spherical Cube (Csc)

Used in COBE data

Arc (Arc)

Similar to Zea but not equal-area

pixelsstr

Selects the pixel dimensions of the image to be produced. A scalar value or a pair of values separated by comma may be given. If the value is a scalar the number of width and height of the image will be the same. By default a 300x300 image is produced.

scalingstr

Selects the transformation between pixel intensity and intensity on the displayed image. The supported values are: "Log", "Sqrt", "Linear", "HistEq", "LogLog".

samplerstr

The sampling algorithm determines how the data requested will be resampled so that it can be displayed.

resolverstr

The name resolver allows to choose a name resolver to use when looking up a name which was passed in the position parameter (as opposed to a numeric coordinate value). The default choice is to call the SIMBAD name resolver first and then the NED name resolver if the SIMBAD search fails.

deedgerstr

When multiple input images with different backgrounds are resampled the edges between the images may be apparent because of the background shift. This parameter makes it possible to attempt to minimize these edges by applying a de-edging algorithm. The user can elect to choose the default given for that survey, to turn de-edging off, or to use the default de-edging algorithm. The supported values are: "_skip_" to use the survey default, "skyview.process.Deedger" (for enabling de-edging), and "null" to disable.

lutstr

Choose from the color table selections to display the data in false color.

gridbool

overlay a coordinate grid on the image if True

gridlabelsbool

annotate the grid with coordinates positions if True

radiusQuantity or None

The radius of the specified field. Overrides width and height.

widthQuantity or None

The width of the specified field. Must be specified with height.

heightQuantity or None

The height of the specified field. Must be specified with width.

Returns
list of image urls

References

1

http://skyview.gsfc.nasa.gov/current/help/fields.html

Examples

>>> SkyView().get_image_list(position='Eta Carinae',
...                          survey=['Fermi 5', 'HRI', 'DSS'])
[u'http://skyview.gsfc.nasa.gov/tempspace/fits/skv6183161285798_1.fits',
u'http://skyview.gsfc.nasa.gov/tempspace/fits/skv6183161285798_2.fits',
u'http://skyview.gsfc.nasa.gov/tempspace/fits/skv6183161285798_3.fits']

get_images(position, survey, coordinates=None, projection=None, pixels=None, scaling=None, sampler=None, resolver=None, deedger=None, lut=None, grid=None, gridlabels=None, radius=None, height=None, width=None, cache=True, show_progress=True)[source]

Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files.

Note that the files will be downloaded when the generator will be exhausted, i.e. just calling this method alone without iterating over the result won’t issue a connection to the SkyView server.

Parameters
positionstr

Determines the center of the field to be retrieved. Both coordinates (also equatorial ones) and object names are supported. Object names are converted to coordinates via the SIMBAD or NED name resolver. See the reference for more info on the supported syntax for coordinates.

surveystr or list of str

Select data from one or more surveys. The number of surveys determines the number of resulting file downloads. Passing a list with just one string has the same effect as passing this string directly.

coordinatesstr

Choose among common equatorial, galactic and ecliptic coordinate systems ("J2000", "B1950", "Galactic", "E2000", "ICRS") or pass a custom string.

projectionstr

Choose among the map projections (the value in parentheses denotes the string to be passed):

Gnomonic (Tan), default value

good for small regions

Rectangular (Car)

simplest projection

Aitoff (Ait)

Hammer-Aitoff, equal area projection good for all sky maps

Orthographic (Sin)

Projection often used in interferometry

Zenith Equal Area (Zea)

equal area, azimuthal projection

COBE Spherical Cube (Csc)

Used in COBE data

Arc (Arc)

Similar to Zea but not equal-area

pixelsstr

Selects the pixel dimensions of the image to be produced. A scalar value or a pair of values separated by comma may be given. If the value is a scalar the number of width and height of the image will be the same. By default a 300x300 image is produced.

scalingstr

Selects the transformation between pixel intensity and intensity on the displayed image. The supported values are: "Log", "Sqrt", "Linear", "HistEq", "LogLog".

samplerstr

The sampling algorithm determines how the data requested will be resampled so that it can be displayed.

resolverstr

The name resolver allows to choose a name resolver to use when looking up a name which was passed in the position parameter (as opposed to a numeric coordinate value). The default choice is to call the SIMBAD name resolver first and then the NED name resolver if the SIMBAD search fails.

deedgerstr

When multiple input images with different backgrounds are resampled the edges between the images may be apparent because of the background shift. This parameter makes it possible to attempt to minimize these edges by applying a de-edging algorithm. The user can elect to choose the default given for that survey, to turn de-edging off, or to use the default de-edging algorithm. The supported values are: "_skip_" to use the survey default, "skyview.process.Deedger" (for enabling de-edging), and "null" to disable.

lutstr

Choose from the color table selections to display the data in false color.

gridbool

overlay a coordinate grid on the image if True

gridlabelsbool

annotate the grid with coordinates positions if True

radiusQuantity or None

The radius of the specified field. Overrides width and height.

widthQuantity or None

The width of the specified field. Must be specified with height.

heightQuantity or None

The height of the specified field. Must be specified with width.

Returns
A list of ~astropy.io.fits.HDUList objects.

References

1

http://skyview.gsfc.nasa.gov/current/help/fields.html

Examples

>>> sv = SkyView()
>>> paths = sv.get_images(position='Eta Carinae',
...                       survey=['Fermi 5', 'HRI', 'DSS'])
>>> for path in paths:
...     print(' new file:', path)

get_images_async(position, survey, coordinates=None, projection=None, pixels=None, scaling=None, sampler=None, resolver=None, deedger=None, lut=None, grid=None, gridlabels=None, radius=None, height=None, width=None, cache=True, show_progress=True)[source]

Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files.

Note that the files will be downloaded when the generator will be exhausted, i.e. just calling this method alone without iterating over the result won’t issue a connection to the SkyView server.

Parameters
positionstr

Determines the center of the field to be retrieved. Both coordinates (also equatorial ones) and object names are supported. Object names are converted to coordinates via the SIMBAD or NED name resolver. See the reference for more info on the supported syntax for coordinates.

surveystr or list of str

Select data from one or more surveys. The number of surveys determines the number of resulting file downloads. Passing a list with just one string has the same effect as passing this string directly.

coordinatesstr

Choose among common equatorial, galactic and ecliptic coordinate systems ("J2000", "B1950", "Galactic", "E2000", "ICRS") or pass a custom string.

projectionstr

Choose among the map projections (the value in parentheses denotes the string to be passed):

Gnomonic (Tan), default value

good for small regions

Rectangular (Car)

simplest projection

Aitoff (Ait)

Hammer-Aitoff, equal area projection good for all sky maps

Orthographic (Sin)

Projection often used in interferometry

Zenith Equal Area (Zea)

equal area, azimuthal projection

COBE Spherical Cube (Csc)

Used in COBE data

Arc (Arc)

Similar to Zea but not equal-area

pixelsstr

Selects the pixel dimensions of the image to be produced. A scalar value or a pair of values separated by comma may be given. If the value is a scalar the number of width and height of the image will be the same. By default a 300x300 image is produced.

scalingstr

Selects the transformation between pixel intensity and intensity on the displayed image. The supported values are: "Log", "Sqrt", "Linear", "HistEq", "LogLog".

samplerstr

The sampling algorithm determines how the data requested will be resampled so that it can be displayed.

resolverstr

The name resolver allows to choose a name resolver to use when looking up a name which was passed in the position parameter (as opposed to a numeric coordinate value). The default choice is to call the SIMBAD name resolver first and then the NED name resolver if the SIMBAD search fails.

deedgerstr

When multiple input images with different backgrounds are resampled the edges between the images may be apparent because of the background shift. This parameter makes it possible to attempt to minimize these edges by applying a de-edging algorithm. The user can elect to choose the default given for that survey, to turn de-edging off, or to use the default de-edging algorithm. The supported values are: "_skip_" to use the survey default, "skyview.process.Deedger" (for enabling de-edging), and "null" to disable.

lutstr

Choose from the color table selections to display the data in false color.

gridbool

overlay a coordinate grid on the image if True

gridlabelsbool

annotate the grid with coordinates positions if True

radiusQuantity or None

The radius of the specified field. Overrides width and height.

widthQuantity or None

The width of the specified field. Must be specified with height.

heightQuantity or None

The height of the specified field. Must be specified with width.

Returns
A list of context-managers that yield readable file-like objects

References

1

http://skyview.gsfc.nasa.gov/current/help/fields.html

Examples

>>> sv = SkyView()
>>> paths = sv.get_images(position='Eta Carinae',
...                       survey=['Fermi 5', 'HRI', 'DSS'])
>>> for path in paths:
...     print(' new file:', path)

list_surveys()[source]

Print out a formatted version of the survey dict