GSC-II positions were computed by means of astrometric calibrations based on reference stars extracted from the. Tycho-2 catalogue (Hog et al ). The GSC-ACT is a recalibration of the Hubble Guide Star Catalog (GSC), version , using the ACT (Astrographic Catalog/Tycho) from the US Naval. Like its predecessor (GSC-I), the GSC-II was primarily created to provide guide star information and observation planning support for HST.


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So you need to turn this feature off in Windows Explorer options, advanced. See note above C: Unzip the files retrieved in step 4 with folders preserved!!!

The HST Guide Star Catalog

Adding the bright star data from this catalog to the GSC produced a complete all-sky catalog down to the GSC limiting magnitude. In addition, many of the false objects due to artifacts around the halos and diffraction spikes of the bright stars were identified and corrected as well as a number of reported gsc star catalog.


The catalog serves as a database which supports the automated scheduling of observations and telescope operation without direct or "realtime" control from the gsc star catalog.

A digital map of the entire sky, the GSC is 60 times larger than any existing catalog and contains almost 19 million celestial objects, including 15 million stars between 9th and 15th magnitude.

Installing the Guide Star Catalog via Download

The plates were digitized into square rasters at 25 um sample intervals using modified PDS microdensitometers. The sky-background was modeled with a bi-dimensional cubic spline approximation to the modal level. Then an object finder, based on locating connected pixels at a certain threshold above the background, was used to obtain, for each plate, a list of positions, sizes, intensities, and related descriptive parameters.

Images with multiple peaks were deblended by an algorithm based on correlations gsc star catalog a library of gsc star catalog images.

Installing the Guide Star Catalog via Download

The identified objects were classified as stars or non-stars by an interactive multivariate Bayesian classifier that used image features from the object-detection steps and gsc star catalog started from a small set of objects visually identified on each plate.

Comparison of classifications from multiply catalogued objects in the plate overlap areas shows that the purity of objects classified as stars is typically 97 percent. Photometric and Astrometric Calibrations: The GSC calibrations were obtained on a plate-by-plate basis by polynomial modeling against the photometric and astrometric reference catalogs.

In Paper II the overall quality of the photometry near the standard stars was estimated from the fits and other tests to be 0.

Additionally, Ratnatunga's comparison gsc star catalog the GSC against totally independent J-band photographic photometry for three southern fields 20 sq deg area for Astrometry, at equinox J, is available at the epochs of the individual plates used in the GSC; and the reductions to the reference catalogs AGK3, SAOC, or CPC, depending on the declination zone use third order expansions of the modeled plate and telescope effects.

The fits to the reference catalogs lie in the range 0. Paper II reported estimates of the overall external astrometric error, produced by comparisons of independently measured positions, in the range 0.


Then from a more extensive analysis gsc star catalog the Carlsberg Automatic Meridian Circle data, Taff et al. In addition, many of the false objects due to artifacts around the halos and diffraction spikes of the bright stars were identified and corrected as well as a number of reported errors.

In reality, the drop in RMS error was probably even greater than indicated in this table. When comparing GSC 1.

[] The Second-Generation Guide Star Catalog: Description and Properties

Note also that some plates gsc star catalog uncalibrated; only the plates listed in the original GSC 1. How to use this data: For a long time, GSC 1.


However, I understand they've ceased doing this. These disks have the same format as the "original" GSC 1. There's an alternative to getting the new CDs.