Table of the 520 MAP asteroids by tenth of H magnitude brighter or fainter than the H MPC magnitude :

H mag # (MAP-MPC) Total MAP objects Total MAP objects 12/2008 (483)
-----------------------------------------------------------------------
0,9 mag brighter ______ 3 asteroids ______________ 3
0,8 mag brighter ______ 2 asteroids ______________ 5
0,7 mag brighter ______ 3 asteroids ______________ 2
0,6 mag brighter ______ 2 asteroids ______________ 3
0,5 mag brighter _____ 10 asteroids ______________ 6
0,4 mag brighter _____ 10 asteroids _____________ 10
0,3 mag brighter _____ 24 asteroids _____________ 17
0,2 mag brighter _____ 17 asteroids _____________ 17
0,1 mag brighter _____ 30 asteroids _____________ 22
difference <0.1 mag __ 50 asteroids _____________ 33
0,1 mag fainter ______ 30 asteroids _____________ 16
0,2 mag fainter ______ 52 asteroids _____________ 36
0,3 mag fainter ______ 57 asteroids _____________ 46
0,4 mag fainter ______ 62 asteroids _____________ 54
0,5 mag fainter ______ 56 asteroids _____________ 61
0,6 mag fainter ______ 42 asteroids _____________ 48
0,7 mag fainter ______ 33 asteroids _____________ 36
0,8 mag fainter ______ 15 asteroids _____________ 23
0,9 mag fainter _______ 8 asteroids _____________ 16
1,0 mag fainter _______ 2 asteroids ______________ 7
1,1 mag fainter _______ 2 asteroids ______________ 4
1,2 mag fainter _______ 3 asteroids ______________ 5
> 1,2 mag fainter _____ 1 asteroids ______________ 8
undefined mag.# _______ 6 asteroids ______________ 5

The comparison between the results of the actual MAP objects and the same in late 2008 MAP show the increase of accuracy of the MPC H magnitudes.

Independently of the increasing total of the MAP objects, the total number
of H MAP differences < 0.2 mag highly increases. For 288 of them (55,4% of the total), the active lightcurve makers have permitted the knowledge of the asteroid lightcurve amplitudes.

A part of the 520 objects of the MAP already have been observed on some
oppositions :

Observed oppositions --2010/02/28--- 2009/05/31
-----------------------------------------------
0 opposition(s) for 004 asteroids______002
1 opposition(s) for 358 asteroids______347
2 opposition(s) for 096 asteroids______089
3 opposition(s) for 044 asteroids______042
4 opposition(s) for 012 asteroids______009
5 opposition(s) for 004 asteroids______004
6 opposition(s) for 002 asteroids______002

Since September 2008, the Minor Planet Center changed the H magnitude of 53922 numbered asteroids, up to January 31,2010
The continual changes of the official H magnitudes also need the necessity
to modify the averaged differences of H magnitudes of the MAP objects.

All the modifications of the changed H magnitudes of the 53922 numbered
asteroids are included in a zipped Excel file down loadable at :
http://astrosurf.com/map/MAP_H_COMP.zip

For the MAP objects concerned by a change of H magnitude, we continue to calculate the difference of H magnitude with the H magnitude of the first MAP measure(s), but a final correction is made to take in account the
change of the H magnitude by the MPC.

The MAP has 520 asteroids in its database. Among them, 141 objects already have their H mag concerned by the recent MPC corrections, at least partially.

Total of resulting new differences of H magnitude ( MAP - MPC ) by tenths of magnitude :
All Asteroids (141) -//- Only asteroids observed 3 oppositions and more (24)
----------------------------------------------------------------------------

New H MPC = H MAP _____ 13 ___ 9,15% __/_ New H MPC = H MAP _____ 5 _ 20,00%
Difference of 0.1 mag _ 34 __ 23,94% __/_ Difference of 0.1 mag _ 7 _ 28,00%
Difference of 0.2 mag _ 21 __ 14,79% __/_ Difference of 0.2 mag _ 1 __ 4,00%
Difference of 0.3 mag _ 24 __ 16,90% __/_ Difference of 0.3 mag _ 4 _ 16,00%
Difference of 0.4 mag _ 13 ___ 9,15% __/_ Difference of 0.4 mag _ 2 __ 8,00%
Difference of 0.5 mag _ 12 ___ 8,45% __/_ Difference of 0.5 mag _ 3 _ 12,00%
Difference of 0.6 mag _ 13 ___ 9,15% __/_ Difference of 0.6 mag _ 2 __ 8,00%
Difference of 0.7 mag __ 7 ___ 4,93% __/_ Difference of 0.7 mag
Difference of 0.8 mag __ 2 ___ 1,41% __/_ Difference of 0.8 mag
Difference of 0.9 mag __ 2 ___ 1,41% __/_ Difference of 0.9 mag _

For the asteroids seen at least during 3 oppositions, the new H MPC are
similar to about 48% ( 0.0 to 0.1 mag of difference ) to the H MAP magnitudes.
The causes of the differences may be : erroneous observed magnitudes, R MPC magnitudes marked V, impact of high light variability
Nevertheless, only 26 averaged differences of H magnitudes increased after
the MPC modifications ( 18.4% of the 141 H modifications by the MPC )
See : http://astrosurf.com/map/COMP_H_MAP-MPC_100131.htm

Among the 520 astéroides of the database, 132 of them - 25,4% of the total
- are no need of a follow-up due to :
- the similarity between their H magnitude of the MAP and a new H from the MPC
- or the averaged discrepancy of the H magnitude of the MAP reduced to
nearly 0, after new complementary measures.
- or by the existence of a half-amplitude of light variability higher than
the averaged discrepancy of the H MAP magnitude and probably responsible of the first differences of H magnitudes. Some of these concerned objects may be have a discrepancy of H magnitude, but it would be difficult to extract the difference of H magnitude from the light-variability. Then these objects are not priority....

The priority objects are about 90 other MAP asteroids which already have
been observed during at least 2 oppositions.
For 36 of them, the MAP already has a good estimation of the difference of the H magnitude. They have a "status" marked in blue in the MAP Database.

These MAP asteroids already observed during two oppositions wait their
third observed opposition to obtain probably the definitive confirmation of their H magnitude difference and the publication of the results !
... then we shall be very interested by your new measures of the MAP
objects in the future ! ;-)

Best wishes
Gerard Faure> end report

Updates at the MAP alert homepage have been completed. Thanks to a headache of a text editor and loss of many page functions, uploading  files is no longer possible. This might indeed be possible but I do know that creating links to the files is not possible, leaving no ways to pass them along. How nice.  So our new attachment page now asks anyone who might want a file to contact me  by e-mail. You will notice the file name at the head of this message contains its  alert number, so as to mate these together at the webpages. I plan to add this  Gerard's files for my book keeping at the attachment  page.  

And last, despite my much growling and knocking about bad weather here, a review of last years observations has resulted in seeing this was not such a bad year at all, now to get started with this years sight's!

Clear Skies!
Lawrence Garrett
ALPO Minor Planet Section Assistant Coordinator
mapalerts@myfairpoint.net
MAP Alert homepage
http://home.myfairpoint.net/lgasteroid1/map/

Gerard Faure
(8297) Gerardfaure
http://www.astrosurf.com/map

m

Hi to all,

As Lawrence is busy, I send this MAP Alert #336.

Lastly, I finished to analyze all the new data since the last update of the
MAP Database since May 31,2009.

This file of the new measures of the MAP Database contains 490 measures for 19 old MAP asteroids and 24 new MAP objects.
This total of 490 measures is consisted of 407 CCD measures and 83 visual
measures.

I join the HTML file to this email.

Among these objects, some seem to show different parts of them, from an
opposition to another. The measures of (1330) Spiridonia for the fourth
observed MAP opposition seem to show two cases of discrepancies for this
object : two low in 2005 and 2008 (slightly fainter than predicted) and two
big in 1999 and 2010 (more bright than predicted) !

Apparently, we have an object which is not observed similarly at each
opposition !

(914) Palisana seems to be similar.
It will be interesting to observe again (914) Palisana and (1330)
Spiridonia during this actual opposition !

Other asteroids were followed by Roger Dymock, for their lightcurve and for their revision of H magnitude : (1176) Lucidor, (2093) Genichesk and (4080)
Galinskij. A very good work !

I yet have to do the lightcurve for (12867) Joeloic.

9 NEA with possible discrepancies of H magnitudes were "found" mainly by John Fletcher, but also by Roger Harvey and Andrew Salthouse.

With all these new measures, the MAP Database will reach more than 6000
measures and more than 500 MAP objects !!

Thank you for all the active measurers !
Best regards
Gerard Faure

Lawrence Garrett
ALPO Minor Planet Section Assistant Coordinator
mapalerts@myfairpoint.net
http://home.myfairpoint.net/lgasteroid1/map/

Gerard Faure
(8297) Gerardfaure
http://www.astrosurf.com/map