Hi,

Yes, UCAC3 is available now but I suggest you not rush to ask a DVD, the USNO 
as probably better thing to do than sending DVD to every amateur astronomer on 
earth.

I not want to add direct access to this DVD from CdC for the many reason 
invoked when I choice to use Catgen for any future catalog in CdC V3.
But I plan to make smaller downloadable version for use with CdC. This will be 
probably more useful for most people here.

This catalog is big, 100 millions stars, it is probably the most useful ever 
produced for the amateur astronomer, so its use on CdC need to be carefully 
planned. 
I want to ask your opinion before to start and provide some small test file to 
be sure all work fine before to upload the big chunks. 

Use this tread to discuss about what you want to be include in this catalog or 
what you not want to save space. 
We can also use other tread for specific issues, I start two after this message 
about stars identifiers and photometry.

You can get all the information about the catalog content on this page, please 
read carefully:
http://ad.usno.navy.mil/ucac/readme_u3.html

My first idea is to produce two version, one the most compact as possible to 
produce nice field map. The other more complete with identifier and search 
index but also a bigger download. 
Remember that each character of information we add increase the download of 100 
MB!

UCAC3 compact : 

Include fields:
RA, DEC, pmRA, pmDEC, Mag : 1.5 GB
or
RA, DEC, pmRA, pmDEC, Mag, B-V : 1.7 GB

So it can be tree files of about 500 MB each with South, Equator and North 
downloadable and installable separately.


UCAC3 with ID , index and maybe other need informations :

Include fields:
ID, RA, DEC, pmRA, pmDEC, Mag, B-V : 2.6 GB 
+
100 MB / char, 400 MB / numeric value, 
+
index size is nbrec * (8 + keylength) : 1.7 GB

Except the index the download can be split in 500 MB to 1 GB parts.


Any idea on this ?

Patrick

Reply via email to