All-Sky Optical catalogue now available for download

[Eric Flesch]

My publications are coming to an end, methinks, but throughout I was
using a homegrown version of an all-sky optical catalogue, the likes
of which seem strangely missing from availability nowadays. Once upon
a time the USNO-B was distributed in Linux, so it was said -- no
evidence of that today, and you can't download the USNO-B today. In
the late 1990's the USNO-A was distributed on 10-12 CDs in a limited
edition -- I've still got mine, but it's vanished elsewhere. And the
APM was "distributed" on tape -- how old does that sound -- but
occasionally parts of it would pop up on web sites -- and I said
"pretty please" to AAO to put some of it on theirs -- and so I got the
whole thing 16 years ago. Today we have SDSS and SuperCosmos which
are terabytes large -- good luck with that.

So I detected a need, and have built an all-sky optical catalogue from
USNO-B, USNO-A, APM and SDSS optical data, it is 1.16 billion objects
in a sparse format which is stored at a mere 9Gb. It's been accepted
by PASA and is now on arXiv at

https://arxiv.org/abs/1705.05434

So if you would like to have your very own all-sky optical catalogue
on your own computer, you can now have one. Hope you like it. As for
me, I think I'm done now but you never know for sure. It seems likely
that I'll be issuing a new Milliquas ("million quasars") catalogue on
NASA HEASARC in July when SDSS DR14 comes out, so I may be around for
a while yet.

cheers,
Eric Flesch
Whakatane, New Zealand
17-May-17

[Steve Willner]

... you can't download the USNO-B today.

I'm surprised it's not at VizieR. What is
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/284 ?

So I detected a need, and have built an all-sky optical catalogue from
USNO-B, USNO-A, APM and SDSS optical data, it is 1.16 billion objects
in a sparse format which is stored at a mere 9Gb. It's been accepted
by PASA and is now on arXiv at
https://arxiv.org/abs/1705.05434

That's still quite a useful catalog.

[Eric Flesch]

Post by Steve Willner

... you can't download the USNO-B today.

I'm surprised it's not at VizieR. What is
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/284 ?

That's an on-line query form for USNO-B data. My statement pertains
to obtaining the entire 80Gb catalog. You're welcome to try that
using the Vizier query but I expect you'd run afoul of some system
limit.

[Steve Willner]

Post by Eric Flesch

Post by Steve Willner
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/284 ?

That's an on-line query form for USNO-B data. My statement pertains
to obtaining the entire 80Gb catalog. You're welcome to try that
using the Vizier query but I expect you'd run afoul of some system
limit.

I'm not aware of any Vizier query limits. Disk space and bandwidth
may be practical limits in some cases, but I wouldn't expect them to
be a problem for 80 GB. (You meant GB, not Gb, didn't you?)

[Eric Flesch]

Post by Steve Willner

My statement pertains to obtaining the entire 80Gb catalog. ...using
the Vizier query but I expect you'd run afoul of some system limit.

I'm not aware of any Vizier query limits. Disk space and bandwidth
may be practical limits in some cases, but I wouldn't expect them to
be a problem for 80 GB. (You meant GB, not Gb, didn't you?)

I've recently downloaded Simbad quasars using the Vizier query and
there was a 20,000 row download limit per each query. Given that
USNO-B has over a billion rows, that comes to 50,000 queries required.
I suspect that even you would find that to be a limit, Steve. :-)