Question from Roy Tucker, forwarded to TASS

[Chris Albertson <chris@topdog.pas1.logicon.com>]

I got some e-mail from Roy Tucker last week.  Many of you may 
know him.  Rather then forward I'll summarize it.

It seems he has a very tass-like project he has been running
my himself for quite some time.  It it's present form he
operates a 1K x 1K CCD in drift scan mode.  Having only one
camera, he collects one hour of data then "rewinds" the system
and scans the same part of the sky again.  He does two "rewinds"
to collect data like a TASS triplet, one hour apart.  He is also
looking at the same part of the sky as TASS for the same reason.
Drift scan simply works best at the equator.  One major difference
is that he is using a C14, not a 135 mm camera lens.  His images
are about 4 or 5 magnitude deeper than TASS Mk III images.  They
are still fairly wide as his CCD has bigger and more pixels than 
the KAF400.  I have seen some samples of his data and by eye they
look just like TASS images when viewed by ximtool.  I see similar
artifacts.

Roy is interested in N.E. Asteroids and has in fact discovered a 
couple of them with his system.  He "processes" his data by eye
by blinking the images.

His question (paraphrased) to me and to the TASS list in general 
is this:  
  "Blinking is very time consuming with many images 
   per night it takes a lot of time and energy.  Is there 
   any software used by TASS that could automate the search?"

I looked at a set on three images he took and used to discover
a N.E. Asteroid so I knew beforehand that there was something
of interest.  I tried blinking them.  What a lot of work!  Even
knowing that there is an asteroid there, it takes a lot of effort
and skill to pick it out.  Maybe one learns over time but I 
never would have found anything on these images.  He takes about 
60 per night and he lives in a place where there are many clear 
nights.  So I can see that automation could help.

If he were to run an object extractor on his images.  He would
have starlists that look just like TASS starlists.  Asteroid search
software would then work on either data source Tucker's or TASS's.

It has been said many times now that TASS (even Mk IV) is unlikely
to discover any new asteroids.  Maybe true, but it may still see
many known asteroids.  Could we measure rotation periods photometrically?
Has this too "been done" and every known asteroid has been measured?
How about if a rotation rate changed? _That_ would be a discovery.
I assume such indirect observation of a collision would be worth
writing a paper about.  Does it happen often enough to be observed?
Has anyone tried looking? 

I had thought that TASS may see some nova.  Most may be to dim but
Mk IV may catch a few.

Our current data processing system will ignore these evens.  I think
we need a "discovery pipeline".  It could run along side the "stellar
photometry pipeline" now taking shape.  If TASS wants to do this and
Roy wants to automate his data reduction it may make sense to work
together or at the least to keep software generalized enough that it
can be shared between the two projects.

For those who want to try their eye at blinking images.  His set of
three FITS images with which he discovered a N. E. Asteroid is at
his home page (see below)   He will be at the San Diego
AAS meeting and has offered to give me a larger sample of data on
CD-ROM.  We can talk about how TASS and his drift scan project may or
may not fit together possibly Sunday or Saturday afternoon. Perhaps
some others would like to meet with him also.

Here is a quote:
> Image scale is
> about 2.56 arcseconds per pixel. The data consists of sets of three scans
> of twenty 512x564 images for a total of about 60 MBytes. As a sample, you
> can download the discovery images of 1998 FG2 from my web site at
> "http://www.azstarnet.com/~gpobs/gpobs.htm". It was a nice, bright 18th
> magnitude at the time of discovery.

-- 
--Chris Albertson

  chris@topdog.logicon.com                Voice:  626-351-0089  X127
  Logicon RDA, Pasadena California          Fax:  626-351-0699