The passage of 2002 MN and TASS

[Tony Beresford <aberesford@iprimus.com.au>]

As most list members would have heard  a small asteroid 2002 MN
was first observed on June 17, having passed earth at only 120,000Km
on June 14.1 UT. Courtesy of Bill Gray ( of Guide fame) ,here is an approximate
ephemeris for the time of closeest approach. The Speed column
is in arcseconds/hour. 
Date (UT)     RA       declination   delta mag  Elong Speed  PA
---------     --       -----------   ----- ---  ----- -----  --

13 Jun 18:00  6h54m53s N46 16' 43"   0.002 19.0  29   10352  335 Aur
13 Jun 20:00  6h37m04s N52 06' 26"   0.002 18.0  31   16918  331 Aur
13 Jun 22:00  5h54m04s N61 18' 59"   0.001 16.3  38   30012  322 Cam
14 Jun  0:00  3h03m05s N72 38' 59"   0.001 14.0  53   51963  282 Cas
14 Jun  2:00 22h06m51s N58 18' 39"   0.001 11.9  80   59873  213 Cep
14 Jun  4:00 20h50m12s N30 30' 47"   0.001 11.2 107   39102  199 Cyg
14 Jun  6:00 20h24m26s N12 31' 56"   0.001 11.3 124   21684  197 Del
14 Jun  8:00 20h11m52s N 2 24' 19"   0.002 11.7 132   12760  196 Aql
14 Jun 10:00 20h04m29s S 3 40' 26"   0.002 12.0 137    8177  196 Aql

Note that as it crossed TOM1's declination strip , between 6 and 8 houurs UT
on June 14, it was moving something like 5 arcseconds/second or 1.5 seconds
per Mark IV pixel. Thus its apparent brightness on an 100 second image would
be something like mag 16. and would be a streak 500 arcseconds or 8 arc minutes
long. I suspect this is below the detectable limit on Mark IV images.
Bigger and brighter objects, say the 1km size objects on the same track 
would be 5 magnitudes brighter at mag 11 apparent. However I am sure it would
be dismissed as an earth satellite streak, given its angular velocity.
It would certainly be very hard to follow, as a delay of an hour in noticing the
object would have had it move out of even the Mark IV FOV.

Tony Beresford ( 5682)