>Hi,does anyone know what astrosoftware can take the AC2000 CD from USNO = >? >AC=3D The Astrographic Catalogue on the System of the Hipparcos = >Catalogue. >Regards >Hans-Goran Guide by project pluto at www.projectpluto.com (currently version 7): once there see under extra datasets or similar link. There are foreign language capabilities too, though mostly German, French, Italian and possibly Dutch Europe-wise. It plots the data in a star charting manner, along with all the other catalogues it plots, and AC2000 info can be found for individual objects via a two tier help dialogue. If you want to manipulate masses of AC2000 data then you've got to go to the old fashioned route of programming or at least using a relational database. Alternatively, AC2000 is part of Vizier, as per the CDS Strasbourg http://cdsweb.u-strasbg.fr/CDS.html . Now, using the graphical interface called Aladin which you can access there, you can plot up a survey plate of a field and then use the Vizier option to overlay numerous objects from many surveys, including stuff from AC2000 and USNO An.0 etc [and now even 2MASS!!!!], each object allowing data to be displayed on a status line at bottom when selected. Using the SIMBAD option you can also overplot objects from a multitude of less massive catalogues, some mind-numbingly obscure. It works online via a java interface, but you can download a dedicated standalone engine [ie browser free] if you also download the SUN java virtual machine. Aladin should be very useful to people making charts of small fields for themselves due to the plethora of capabilities and catalogues, and you soon get the hang of it as it is fairly straightforward. Cheers John PS in fact, you can go mad in Guide (or Aladin) and have all the data plotted up for a star from GSC, AC2000, UCAC1, USNO An.0, Tycho1 [Tycho2 also when Guide 8 comes out], HIP etc... ...which is a good way to check how incredibly inconsistent magnitudes are between one catalogue and another, even if some sort of conversion trick is used to "transfer" 'em to "V". After all, these catalogues ain't meant to be primarily photometric, but folk will forget that ;)