----- Original Message ---- > From: Sander Pool <[email protected]> > > I trust the USNO is a mature organization that can throttle the number > of discs it sends out or put usage restrictions on what people can ask > them for.
(Well I misread that as "put restrictions on which people can ask for them", so my first paragraph isn't directly applicable, but I'll leave it in since it helps explain the situation) The problem with restrictions is that many amateurs use catalogs from the USNO for many various "real science" uses, but they often have no formal affiliation with established science/educational organizations, so there's no practical way to "regulate" distribution of discs from the USNO that would still allow these amateurs to get them. But the USNO also has limited resources for this. Much USNO activities, especially producing astrometric catalogs like this, is a throwback to the days when accurate navigation was much more directly related to star positions. These days, for an admiral in the Navy's budget office in the pentagon (or wherever it is), it probably looks like a low priority- interesting to geeks but of limited practical value to the military. There are perhaps a few hundred users who have a legitimate scientific need for these catalogs, and the impression I get is that there are only a few people at the USNO involved in produing them. In other words, it's a very low budget operation. So they're forced to rely on individuals to be reasonable in making requests for discs. For earlier catalogs, it has been common for them to run out of discs and have no funding for further distribution. But by then it's usually available online through CDS/Vizier, although downloads of the full catalog would require a very fast connection. If you're planning to convert the catalog for use by CdC users, that sounds like a reasonable reason to request a disc. But it would be bad if every CdC user requested his own disc from the USNO. -John > I said I planned to integrate the catalog into CdC but it's > quite possible they didn't even read that, who knows. Besides, my tax > dollars help pay for it all so I don't feel bad that I received a disk > :) And neither do I feel bad if they send out a few hundred disks to > other interested parties around the world. This is an excellent use of a > few DOD (department of defense) budget dollars. The more this catalog > spreads, the better. > > Thanks, > > Sander > > Patrick Chevalley wrote: > > > > > > 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 > > > > > > > ------------------------------------ > > Yahoo! Groups Links > > >
