Gliese catalogue implementation

[ajtribick]

Some thoughts on implementing the Gliese catalogue:

First off, the numbers are all below 10000, which means a two-byte integer would be sufficient to store them. This leaves the issue of the fractional Gliese numbers - what range do the fractional parts span? Provided it is a small range (which probably is the case), the high bytes of a four-byte integer could be used to store the part after the decimal point (if zero, then don't use the point).

Then there's the issue of Gliese vs GJ. What seems to be the case is that numbers below 1000 (including fractional numbers) go in the Gliese catalogue (abbreviation Gl), numbers 9000 and above go in the Woolley extension (abbreviation Wo), numbers between 1000 and 2999 are Gliese-Jahreiss (GJ) and the rest are unnamed (NN = No Name).

However GJ seems to be interchangeable with the other designations, and Woolley doesn't seem to get used much. As far as I can tell, NN is never used and these numbers are referred to using GJ.

What I would suggest is display numbers below 1000 as Gliese #, above 1000 as GJ # (maybe use Wo for Woolley, but use GJ for the NN stars). However input should allow any of the catalogue names, so you could refer to Gliese 876 by either Gliese (Gl) or GJ.

I'm not entirely sure if there are some stars which have both fractional Gliese numbers and also integer GJ/NN numbers.

Also, where would a cross-reference between Gliese/GJ/NN/Wo and Hipparcos be available?

[t00fri]

You don't touch at all the quality issues.

The original Gliese catalog is almost 50 years (!) old with the latest update being from 1991. It uses 1950 coordinates, which is awkward. No idea what quality level the listed parallax values have...

Before discussing catalog numbering, did you do some research as to those crucial precision issues in relation to the HIP data base?

Bye Fridger

[ajtribick]

Sorry, I should have made it clear I am talking about making a cross-reference file, similar to the HD and SAO cross-references we already have.

[t00fri]

Some thoughts on implementing the Gliese catalogue:
...

Sorry, I should have made it clear I am talking about making a cross-reference file, similar to the HD and SAO cross-references we already have.

Oh...indeed I think that was not so clear

Anyway, then I am not worried.

Bye Fridger