For each useable image, the magnitude of the SN was determined using AstroArt 5.0 and differential ensemble photometry based on 10 nearby comparison stars with V magnitudes derived from the Guide Star Catalog
The USNO B1.0 database includes about a billion stars, and the Guide Star Catalog
II will contain about two billion stars and galaxies when it is done.
The main package comes with a subset of the Smithsonian Astrophysical Observatory (SAO) Catalog with stars down to about magnitude 8 but there are also options to use the full SAO, the Hubble Guide Star Catalog
(GSC), and the complete Hipparcos, Tycho, Tycho-2, and US Naval Observatory UCAC2 databases.
The program includes corrections for atmospheric refraction, the ability to switch between 2000.0 and 1950.0 coordinates, and the 18 million stars from the Hubble Guide Star Catalog
. On the other hand, setting magnitude limits--a standard feature of most planetarium software--is maddeningly imprecise.
The advanced edition of version 5 of STAR Atlas:PRO for Windows 95 and higher (AU$191.50) now accesses the Hubble Guide Star Catalog
2 and the USNO A2.0 databases via the Internet to provide more than 500 million stars.
For starters, Lite doesn't have the Hubble Guide Star Catalog
; but this omission is acceptable given the target audience of beginner and casual observers.
This new release now incorporates the Hipparcos and Tycho-2 star catalogs, and it has version 1.3 of the Hubble Guide Star Catalog
. As a result, positional and duplication errors are much reduced.
The program incorporates the Hipparcos and Tycho star catalogs, as well as the larger Hubble Guide Star Catalog
, and allows the user to manipulate the data in interesting ways.
In addition, Sky Simulator does not support faint-star catalogs such as the Hubble Guide Star Catalog
and the USNO A2.0.
In these days of the Hubble Guide Star Catalog
, the use of the Bright Star Catalog might sound restrictive, but the latter provides valuable background information about each entry, and the choice is a sensible one in view of the target audience for the software.
(Leaving the Hubble Guide Star catalog
on the CD saves another 390 megabytes.) Updating the orbit databases used up 20 megabytes on the local drive, but this is still a drop in the bucket, considering the multi-gigabyte drives in modern computers.