Optical and UV Spectrophotometric Standard Stars

Contact Jack Dembicky for web page errors, corrections, ommisions, and/or additions.

This page last updated: June 8, 2005 - JMD
This page last checked: November 7, 2004 - JMD

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Welcome to a tool for finding suitable optical and ultra-violet spectrophotometric standard stars on the sky most appropriate to reduction of astronomical spectroscopic observations.These pages are a based on the original pages develped by J. R. Walsh at ESO. Apache Point expresses its thanks to J. R. Walsh and to ESO for allowing us to place a copy of these pages at Apache Point.

This resource consists of a set of WWW pages each devoted to a single spectrophotometric standard star and containing positional information, magnitude, a finding chart and plots of the magnitude and flux against wavelength, as shown on an (example page). The Right Ascension and Declination are in the HST Guide Star Catalogue coordinates (equinox 2000).

The finding charts have the conventional orientation, north at the top and east to the left and the image dimensions are indicated. If not arrowed, the standard star is the one in the centre of the field.

Access to the standards is either through:
an RA ordered list;
an RA-Dec sky map with star positions (to enable the closest standard star to your observed source to be quickly identified).

The data for the standard stars come from four sources:

• HST UV spectrophotometric standards. Data for 23 stars based on IUE and optical spectra and calibrated by the primary WD standards. Also data on 6 more stars with IUE and model spectra.
• Optical spectrophotometric standards from Oke (1990). Data for 25 stars (7 to 16 mag.) from 3200 to 10200A based on Hale 5m observations.
• Optical spectrophotometric standards from Hamuy (1992, 1994). Data for 10 bright secondary standards and 19 fainter (10 to 14 mag.) tertiary standards over the wavelength range 3300 to about 10300A, mostly in the southern hemisphere, taken with CTIO telescopes.
• White Dwarf primary spectrophotometric standards. Data for 4 stars (11 to 13 mag.) from 10A to 3 microns based on White Dwarf model atmospheres and HST FOS observations, from the CALSPEC data base at STScI.

The data from which the plots were produced are also available by ftp access from the standard star pages.

A.U. Landolt's standards are available from his paper 1992 AJ 104,340.

Some of the finding charts were produced from the Digitized Sky Survey produced by STScI and based on plate material from the UK Schmidt Telescope and the Oschin Schmidt Telescope.

Suggestions for further standard stars to include are welcome.