Hi,
Most of the really fast moving stars are so bright that they will be
completely unobservable by LSST, so my guess is we won't see anything
faster than maybe 1 arcsec/yr. But even if you figure that we might
pick up some faint nearby star with fast proper motion like Barnard's
star, there is a pretty clean gap between 10 arcsec/yr and 60
arcsec/day. It's of course true that a solar system object can
briefly be completely stationary, but MOPS should sort this out without
much trouble.
I think splitting the groups is not a big issue. But, as we have
mentioned a time or two at past meetings, care is needed when doing
difference imaging with high-PM objects.
Tim
Chris Smith wrote:
Soooo...
I think it's true to say that it is oversimplification to say "fast
movers" and "slow movers". Isn't this really a continuum, albeit
possibly not equally populated in "velocity" space?
So if we're going to split this continuum into two groups, has the
dividing point been explicitly identified?
Cheers,
Chris
On Nov 22, 2006, at 10:22 AM, Tim Axelrod wrote:
Right, but these will be picked up by MOPS as solar system objects
and handled with the others.
Tim
Kem Cook wrote:
Well, there are TNOs which move at apparent rates (reflex of
Earth's motion)
of about an arcmin per day. They also really move about a degree a
year.
Cheers,
Kem
Hi,
Yes, the rapid movers will be kept track of in the orbits
catalog. The
slow movers are all nearby stars, and move *very* slowly. The
fastest
is Barnard's star at 10.3 arcsec per year. So I think we're safe.
Tim
Jacek Becla wrote:
Yes, I think the fast moving objects will be kept in a separate
catalog (called Orbit Catalog I think), and the issue I am raising
is for slow moving objects. So the question is whether slowly moving
object can move more than one chunk per night?
thanks,
Jacek
Serge Monkewitz wrote:
Kem - I just assumed there was a seperate table for moving
objects so
this is good to hear, but ... what about really slow movers? Will
the MOP be able to detect and track an object that crosses a chunk
over the course of 6 months? 1yr? Put another way, do we need to
assume some kind of small but still significant (over the course
of a
release cycle) velocity for objects in the main object table
(especially leading up to DR1 since the deep/moving pipelines won't
have had very much time to discover/tell eachother about such
objects)?
Thanks,
Serge
On Tue, 21 Nov 2006 16:43:06 -0800, Kem Cook
<[EMAIL PROTECTED]>
wrote:
Hi Jacek,
Your partitioning makes perfect sense, but there will be a few
objects
which move more than quite a bit more than 1 chunk per night.
But, I
think we were going to be keeping the moving obectsd in a separate
table,
for this, as well as other, reasons.
cheers,
Kem
Keywords: DataAccWG
Hello,
Here is a brand new suggestion how to partition Object table
for the nightly processing use case:
http://www.slac.stanford.edu/~becla/tmp/
objectTablePartitioningAtBase.doc
Hope we will have time to talk about it during the telecon
tomorrow.
Jacek
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Dr. R. Chris Smith EMAIL: [EMAIL PROTECTED]
National Optical Astronomy Observatory
Cerro Tololo Inter-American Observatory
950 N. Cherry Ave. Casilla 603
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Office: 520-318-8555 FAX: 520-318-8170
WWW: http://www.ctio.noao.edu/~chris
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=
begin:vcard
fn:Tim Axelrod
n:Axelrod;Tim
org:;Large Synoptic Survey Telescope
email;internet:[EMAIL PROTECTED]
title:Data Management Project Scientist
tel;work:520-322-8735
version:2.1
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