Re: "new" objects are just ordinary stars ...

["Shawn Dvorak" <sdvorak@bright.net>]

A search using "Guide" from Project Pluto showed that there were no *known*
asteroids brighter than mag 14 anywhere near any of the 13 mystery objects,
including the "moving" star.

Shawn

----------
> From: Stupendous Man <richmond@a188-l009.rit.edu>
> To: tass@wwa.com
> Subject: "new" objects are just ordinary stars ...
> Date: Friday, May 22, 1998 4:02 PM
> 
> 
>   I've checked the objects Chris mentioned in a message earlier this
> week: he found 13 objects in the TASS scans which did not appear in the
> USNO catalog.  
> 
>   I looked at the Digitized Palomar Sky Survey via Skyview
> 
>           http://skview.gsfc.nasa.gov/cgi-bin/skvadvanced.pl
> 
> at the position of each object, and found that each one matches
> a star in the plates.  Each star is also in the Hubble Guide Star
> Catalog.  Specifically,
> 
>         Chris object ID         GSC ID            star mag
>         --------------------------------------------------------
>          10003825              0002_00649         10    (double?) 
>          10006686              0002_01141         11.3
>          10006736              0003_00509          9.8
>          10006856              0003_00708         11.2
>          10006898              0003_00579         10.8
>          10153905              5242_00466
>          10154628              5242_01077         11.9
>          10155146              5242_00530         10.5
>          10162983              5251_00790         11.2
>          10171104              0587_00592         10.5
>          10171200              5253_00394         11.4
>          10171277              0587_00461         10.5
>          10171878              5253_00249         10.2 (close double)
> 
>   Some of these stars were bright enough to have diffraction spikes and
> a halo in the photographic image; others weren't.  I saw no common
> feature to them.
> 
>   I don't know why these objects didn't appear in the "tassm16" list.
> If I look at the full USNO A1.0 catalog, I find some.  For example,
> the second object above (the "moving" one) has this entry:
> 
> >    RA            Decl.           Mag.      Radius     Angle
> >  hr mn sec     dec mn sec      Red  Blue    arcsec      deg
> >  
> >  00 19 52.577  +01 08 57.01   11.7   0.0m     2.7      222.9
> 
> 
>   The TASS position quoted by Chris was usually about 3 arcsec north of
> the GSC position; since only a few scans were combined in his analysis,
> this isn't too bad.
> 
>   I looked at the special case of the "moving object".  This corresponds
> to the position of a fixed star.  It's possible that an asteroid might
have
> been moving past the star on the nights in question, since this area is
> right in the middle of the ecliptic.  I guess we just won't know.  
> It's also possible that he picked a star with small random variations
> in position which just happened to increase in RA for the first 5 out of
> 6 detections.
> 
>   Now, I don't want to discourage anyone.  It looks to me like these
> particular objects aren't "new"; they're just missing from a catalog
> against which we matched.  But Chris' exercise shows how easy it is
> to look for and find _something_ of interest -- now we can ask,
> "why are these stars missing from the tassm16 catalog?", and that
> may itself lead to some interesting results.  
> 
>   By the way, the "JD" reported in Chris' E-mail message is the encoded
> value from the database.  The real RA is
> 
>                real RA = [ (database RA)/1,000,000 ]  + 2,540,000
> 
> So the first entry, "JD" = 696720180, corresponds to a true
> Julian Date of 2450696.72, or Sep 5, 1997 UT 5:16:48.  The next two
> entries are at intervals of about 0.04 days = about 1 hour.
> 
>   I have placed the new version of Chris' DBMS code onto the TASS home
> page's "software" site.  
> 
>   The quarter has ended here at RIT.  I am now almost free to work on
TASS
> stuff.  Rah rah!
> 
>                                       Michael Richmond
> 
>