10 YEARS OF VISUAL AND CCD PHOTOMETRY OF ASTEROIDS FOR THE MAP

SUMMARY

INTRODUCTION

HISTORY OF THE MAP

RESULTS OF THE MAP ON OCTOBER 30,2006

ANALYSES OF THE MAP RESULTS

THE TOOLS OF THE MAP

METHODS AND DEVELOPMENT

VISUAL METHOD
USE OF THE CCD MEASURES UP TO 2005
DEVELOPMENTS FOR THE INCREASE OF ACCURATE CCD MEASURES

CONCLUSIONS

INTRODUCTION

Since 1801, more than 362500 asteroids have been discovered and 145705 of them are numbered at mid-
December 2006

The observed magnitudes of the minor planets are useful for :
the computation of the absolute magnitudes
the constitution of the ephemerides
the estimation of  the rough diameters of the asteroids

Evolution of the magnitude types for the asteroids and their absolute magnitudes

Up to 1985, the absolute magnitude B(1,0) was based on the photographic B band of the UBV system
The photographic plates were at that time the tool of the observatories
The magnitudes B(1,0) used then were issued from published lists officialized in 1978

After 1985, there was a change of band for the absolute magnitude renamed H and passing to the V band
The standard conversion from the B magnitude to V had been made by H = B(1,0) -1,0 mag

Actual Formula for the computation of the V magnitudes of the ephemerides :
Based on the absolute magnitude of an asteroid located at 1 astronomical unit to the Sun and Earth
Formula adoptes by the IAU commission 20 in November 1985 :

magnitude = H + 5 * log(r*delta) - 2,5 * log [ (1-G)*phi1 + G*phi2 ]
with
phi1 = exp[ -3,33*(tan (bęta/2) )0,63]
phi2 = exp[ -1,87*(tan (bęta/2) )1,22]

H is the averaged absolute magnitude in the V band, with the solar phase angle = 0°
G is the slope parameter ( standardized to 0,15 if the G parameter is unknown )
r and Delta respectively are the heliocentric and geocentric distances
Phi 1 and Phi 2 are two phase functions
beta is the angle phase

NB : The formula predicts the observed opposition surge and the non-linear drop off in brightness at large phase
angles and is valid from 0 <= beta <= 120 degrees

Various remarks :
The H magnitudes of the numbered asteroids have been used for the first time in the "Ephemerides
of Minor Planets" of 1988

Some modifications of these H magnitudes have been made mostly in 1992 and other revisions for the
last time in 1998

The asteroids with problems of magnitude are numerous : about 1 on 10 observed objects
(estimation based on the total of MAP or pre-MAP objects with regard to the 4500 different objects seen by Harvey)

Various differences of absolute magnitude have been reported by the visual observers before 1996.
The most part of the high discrepancies seen before 1998 have been taken in account by the MPC :

TABLE OF OBJECTS WITH A HIGH DISCREPANCY OF ABSOLUTE MAGNITUDE - 1980 TO 1996
NAME AND NUMBER  DIFF.   NAME MAG. MAG. MAG. MAG.
ASTEROID MAG. DATES OBSER- B(1,0) H H H        REMARKS
SEEN   VER EMP87 88-91 92-97 1998 to
( F= fainter or B= brighter than predicted in the annual EMP )   2006

316 Goberta   1,2 +B 88/11/11 Pilcher 11,5 11,5 9,8 9,8 Correction on EMP92
473 Nolli   1,0 +F 88/02/10 Harvey - 10,0 12,3 12,3 Correction on EMP92
1206 Numerowia   1,6 +F 89/10/22 Harvey 12,4 9,5 11,2 11,8 Correction on EMP92
1212 Francette   2,0 +F 80/02/12 Pilcher 8,0 9,4 9,5 9,54 Correction on EMP87
0,8 +F 83/08/09 Fabre
2,2 +F 85/10/10 Harvey
1293 Sonja   1,8 +F 92/11/08 Harvey 15,4 14,0 12,0 12,0 Error on EMP92
1,3-1,6 +F 96/08/09 Faure
1656 Suomi   1,0 +F 87/11/21 Harvey 15,4 13,1 12,4 12,4 Error on EMP87-92
1,1 +F 96/02/24 Faure
1663 Van Den Bos 1,5 +B 90/11/12 Harvey 14,9 13,7 12,2 12,2 Correction on EMP92
1890 Konoshenkova 1,0 +F 95/12/21 Harvey 12,6 11,2 10,8 10,8 Error on EMP92 ?
2143 Jimarnold   2,5 +F 97/08/31 Faure 15,3 14,1 11,2 14,3 Correction on EMP98
2183 Neufang   1,0 +F 90/06/20 Harvey 12,6 11,4 11,5 11,5
2491 Tvashtri   1,5 +F 87/01/03 Harvey 14,6 13,7 13,7 13,68
2791 Paradise   1,3 +F 88/01/24 Harvey 13,0 11,5 12,2 11,5
3578 Carestia   1,8 +F 91/10/04 Faure - 10,5 8,1 11,6 Error on EMP 89/92
1,9 +F 91/10/13 Harvey
3,0 +F 96/07/22 Garrett         Correction on EMP98
3,1 +F 96/09/04 Garrett
3873 Roddy   1,4 +F 92/12/03 Harvey - 13,1 11,8 12,0 Error on EMP92
1,3-1,6 +F 96/06/11 Faure
4116 Elachi   1,2 +F 94/03/16 Harvey - 13,3 13,0 13,2
4729 1980 RO2   1,3 +B 90/10/17 Harvey - - 13,1 13,0
4744 1988 RF5   1,2 +F 91/01/26 Harvey - 11,6 10,9 11,1 Error on EMP92 ?
5641 Mc Cleese   1,7 +F 95/03/25 Harvey - - 12,7 12,7
5905 Johnson             1,1-1,4 +F 95/08/02 Harvey - - 13,0 13,2

Causes of the high discrepancies of H magnitude

Eventual errors of the photographic magnitude measures which served as basis for the calculation of
the absolute magnitudes B(1,0) modified after in H magnitudes

New inaccuracies relating to the standard conversion from B(1,0) to H by H = B(1.0) + 1.0 mag, for
some of the first thousand of numbered asteroids

The H Magnitudes of the new numbered minor planets often computed from magnitudes of different
color bands, and/or sometimes with a small number of photometric measures, the actual main goal of
the MPC being to do accurate orbital elements for the legions of new discovered asteroďds

HISTORY OF THE MAP

Late in the year 1996, creation of the "Magnitude Alert Project" ( MAP ) by Lawrence GARRETT from the
ALPO Minor Planet Section ( Association of Lunar and Planetory Observers ) to do messages of alerts on the
asteroids suspected to have a real magnitude different from the predicted magnitudes of the ephemerides.
He was helped by Dr. Richard Binzel in getting the start of the Magnitude Program

As I also had the same wish for the asteroids with magnitude discrepancies, I joined immediately the MAP.
Soon, we completed the MAP by a program of follow-up of the MAP objects, for the estimation of their true H
magnitude.
As a member of AUDE ( Association des Utilisateurs de Détecteurs Electroniques, managed by Dr François COLAS
as the Chairperson ), I proposed to do measures for the MAP to the other AUDE members

This Observation project then is run by the Minor planet Section ( Prof. Frederick PILCHER as the coordinator
and Lawrence GARRETT as the acting assistant coordinator ) and by the French AUDE association.

The goals of the MAP are then to find the asteroids with errors of H magnitude equal to 0,3 magnitude and
more, and to follow the MAP objects on many oppositions for a better estimation of the true H magnitude

For this goal, we must obtain many measures in V or similar to V and made on several oppositions,
by several observers, to permit STATISTICALLY the elimination of the sources of errors (variability,
personal deviation and various causes of random errors ).

For that, some measures made during a night on one or some MAP objects always are useful.
It's an easy task, feasible on a part of nightor between two other types of observations.

THE ACTUAL NICHE OF THE MAP ( AMONG THE AMATEURS )

ASTEROIDS < 6 UA OCCULTATIONS     LIGHTCURVES   MAP

DIAM. >  75 KM   Known accurate orbit
Sure occult. Sites
sűre H mag to 0.1 mag     => out of MAP goals

Diameter    very accurate   no
0.01 mag H accuracy with help lightcurve Adjustment on    no
albedo   with help lightcurve the V band to do.   no
taxonomical type   with help lightcurve   no
period of rotation     no   yes        sometimes possible
Light variability     no   yes     seen if high
visible shapes of object   yes   yes   no

DIAM. <  75 KM   Orbit less accurate
Narrow width of occ.line

0.1 mag H accuracy   not easy difficult adjustment on V band possible
estimation of diameter   not easy ( faint stars + filters )   possible
period of rotation   no   yes        sometimes possible
Light variability   no   yes   seen if high
visible shapes of object   not easy   fairly good   no

OBLIGATION TO OBSERVE AGAIN THE OBJECT AT SEVERAL OPPOSITIONS

From 1997 to 2002, the observers of 2 associations formed the hard core of the MAP observers :
The visual observers of the ALPO Minor Planet Section
The AUDE  observers using CCD cameras

All the 6 most active visual observers are members of the virtual club named "Millenium Club", which contains,
with Paul COMBA and Tom LASKOWSKY, the eight observers who observed visually MORE THAN 1000
DIFFERENT ASTEROIDS ... and even several thousands as Roger HARVEY, unmatched world record
holder with more than 4400 minor planets !

The CCD observers, mainly AUDE members, discovered since 1996 many asteroids , supernovae and
made numerous lightcurves which permitted the discovery of several binary asteroids, but also many
variable stars in the images of the followed asteroids ( group "CDR-CDL" managed by Raoul BEHREND )

Some other active CCD observers, notably Americans ( Brian WARNER from the CALL,... ) or Italians ( Sergio
FOGLIA et al ) also made measures for the MAP, directly or indirectly during their lightcurve work.

Since 2003, the activity mainly continued visually
The difficulties to obtain accurate CCD magnitudes by the amateurs were the causes of the retirement by
a majority of the CCD observers
Reorientation from a part of the CCD observers toward the asteroid lightcurves, more easy feasible and
more desired by the professional astronomers.

TABLE OF THE MORE ACTIVE MAP OBSERVERS
In blue, the visual observers  In gold, the CCD observers ( measures often linked to lightcurves )

OBSERVER  NAME     TOTAL OF MEASURES visual CCD CCD  CCD
( on December 31,2006 ) estimations  Tycho USNO GSC

Gérard FAURE     France 715   667 44 4
René ROY     France 474     402 72
Andrew SALTHOUSE     USA 295   295
Roger HARVEY     USA 293   293
Jean-Marie LLAPASSET     France 200     132 68
Pierre ANTONINI     France 174     92 82
Bernard CHRISTOPHE     France 138     138
Lawrence GARRETT     USA 122   122
Claude BOIVIN     Canada 110     78 32
Stefano SPOSETTI     Swiss 102     26 60 42
Robin CHASSAGNE     France 91     39 52
Stephane MORATA/Didier MORATA France 68     43 25
Raoul BEHREND ( +6 MOWLAVI + REVAZ) Swiss 64     54 10
Frederick PILCHER     USA 62   62
Bruno  CHARDONNENS     Swiss 43     43
Olivier THIZY     France 42     1 41
Serafino Zani Observatory   Italy 41     41
(FOGLIA,CREMASHINI, MARINELLO, PIZETTI)
Emmanuel BROCHARD     France 34     17 17
Raymond PONCY     France 33     18   15
Fernand VAN DEN ABBEEL   Belgium 29     14 15
Dennis CHESNEY     USA 27     27
Ben HUDGENS     USA 26   26
Philippe MARTINOLE     France 24     24
Jean-Gabriel BOSCH     Swiss 23     23

CHARACTERISTICS OF THE VISUAL OBSERVERS OF THE MAP, ON DECEMBER 31,2006
(by chronological order of entrance in the Millenium Club)

visual Visual Actual   Obser- Local Total  Total    Honoured
Observers activity teles- Country vation limit obser- different by the
since cope   site mag. vations asteroids asteroid
......

PILCHER 1968 35 cm USA Illinois 14,9 > 4500 1816   (1990) Pilcher

HARVEY 1974 73 cm USA North 16 > 9500 4493   (4278) Harvey
Carolina

FAURE 1975 20 cm France Isere 16,5 ~ 4600 1974   (8297) Gerardfaure

SALTHOUSE 1965 44 cm USA New  14,5 18600 1728 not yet
Jersey

HUDGENS 1972 40 cm USA Texas 15,5 > 4500 1980 not yet

GARRETT 1974 32 cm USA Vermont 15,9 > 2500 1223 not yet

THE SIX MORE ACTIVE VISUAL OBSERVERS IN THE MAP

Frederick PILCHER             Roger HARVEY               Gérard FAURE

Andrew SALTHOUSE              Ben HUDGENS         Lawrence GARRETT

THE ASTRONOMICAL EQUIPMENTS USED BY THE VISUAL OBSERVERS

C 14  PILCHER

Type of Celestron 14 used by Frederick PILCHER   Dome and 29 inch Telescope from Roger HARVEY

Celestron 8 and movable panels used by Gerard FAURE     Andrew SALTHOUSE and his 17 inch telescope

Ben HUDGENS and one of his telescopes ( Meade 16 )     Lawrence GARRETT near his 13 inch telescope

The five American observers use big telescopes but are hindered by the light pollution of the nearest cities.
Contrary to all expectations, the small telescope of 20 cm, used under a pure mountain sky, has
one of the highest limit magnitudes.
The theoritical limit of magnitude for a telescope is soon exceeded, when the observer can see through an
eyepiece, under a pure and quiet sky, at more than 20° over the horizon and by high magnification.

RESULTS OF THE MAP ON OCTOBER 30,2006

MAP asteroid by group :
Near Earth Asteroids   42
Mars-crossers   27
Hungarias   8
Cisjovian Belt   332
Jupiter-trojans and jupiter-crossers   7

asteroids in the MAP Database on October 27,2006 416

Distribution of the MAP objects by thousand of numbered asteroids

Groups of numbers Total

1 to 999     43
1000 to 1999   91 included 3 Mars-crossers
2000 to 2999   38
3000 to 3999   20 included 1 NEA and 3 Mars-crossers
4000 to 4999   37 included 1 NEA and 3 Mars-crossers
5000 to 5999   43 included 2 NEAs and 5 Mars-crossers
6000 to 6999   40 included 3 NEAs and 3 Mars-crossers
7000 to 7999   23 included 1 NEA and 2 Mars-crossers
8000 to 8999   4 included 1 NEA
9000 to 9999   6 included 1 NEA

10000 to 19999   28 included 3 NEAs
20000 to 29999   7 included 3 NEAs and 1 Mars-crossers
30000 to 39999   4 included 2 NEAs
40000 to 49999   5 included 3 Mars-crossers
50000 to 135000   7 included 4 NEAs and 3 Mars-crossers
Unnumbered   20 included 20 NEAs
416

The "bright" objects of the seven first thousands are more accessible by the amateur observers of the MAP
Beyond the N°10000, NEA and Mars-crossers often are the objects which are possibily visible by the amateurs

Distribution of the MAP Asteroids by official H magnitudes :

absolute Total       NEA Mars-         Hungaria Cisjovian   Jupiter-
Magnitude       crosser     belt   trojans

mag H = 8 9           5   4
mag H = 9 15           14   1
mag H = 10 53           52   1
mag H = 11 111     1   1 109
mag H = 12 113     12   3 98
mag H = 13 64   1 7   4 51   1
mag H = 14 11   2 6     3
mag H = 15 6   5 1
mag H = 16 9   9
mag H = 17 5   5
mag H = 18 8   8
mag H = 19 3   3
mag H = 20 7   7
mag H = 21 2   2
416   42 27   8 332   7
% on Total     10% 6%   2% 80%   2%

The size of the smallest object of each group decreases with the increasing distance to the Earth

Averaged difference of absolute H magnitude in the MAP, by tenth of magnitude :

Averaged.Diff. B/x,x F/x,x Total  %  cumul %   Legend
V band Objects Objects    Objects   B/x,x = x,x mag brighter than predicted
F/x,x = x,x mag fainter than predicted
0 mag 5 5 10 2,43% 2,43%   Total = Total objects by averaged diff.
0,1 mag 15 15 30 7,28% 9,71%   % =   % of the total of MAP objects
0,2 mag 23 25 48 11,65% 21,36%
0,3 mag 17 46 63 15,29% 36,65%
0,4 mag 14 41 55 13,35% 50,00%
0,5 mag 7 62 69 16,75% 66,75%
0,6 mag 4 36 40 9,71% 76,46%
0,7 mag 1 33 34 8,25% 84,71%
0,8 mag 3 17 20 4,85% 89,56%
0,9 mag 4 15 19 4,61% 94,17%
1,0 mag   4 4 0,97% 95,15%
1,1 mag   4 4 0,97% 96,12%
1,2 mag   3 3 0,73% 96,84%
1,3 mag   4 4 0,97% 97,82%
1,4 mag   3 3 0,73% 98,54%
1,5 mag   1 1 0,24% 98,79%
1,6 mag   4 4 0,97% 99,76%
1,7 mag     0,00% 99,76%
1,8 mag     0,00% 99,76%
1,9 mag     0,00% 99,76%
2 mag     0,00% 99,76%
2,6 mag   1 1 0,24% 100%
93 319 412
Undefined     4
Grand Total 416

A majority of MAP objects are fainter than predicted.
The discrepancy of light is below 0.5 magnitude for 50% of the MAP objects.
Nevertheless, 5% of the MAP objects have a discrepancy of H magnitude H superior or equal to 1.0
magnitude and more  !

Actual state of the MAP objects :

Objects put in the MAP because observed with at least 0,3 mag of difference between predicted and
observed magnitudes

Total of oppositions followed for the MAP objects :

29 MAP objects seen at 3 oppositions and more
74 MAP objects seen at 2 oppositions
313 MAP objects seen at 1 opposition

On October 17,2006, are noted as without possible H magnitude discrepancy in the MAP :

53 objects with difference < half-variability, following the accumulation of measures
6 unnumbered NEA, for which the MPC rectified its H mag to a value similar to the MAP H mag
13 objects for which the successive measures brought back the difference < 0,2 or even 0,1 mag

72 MAP objects, then 17,3% of the total

Like this, this is the indirect proof of the efficiency of the statistical processing of the measures.
( minoration of the impact of the natural variability of the asteroids and of the errors of measures )

344 other MAP asteroids need more measures !
The most urgent goals are the objects with a high discrepancy of magnitude and those
observed at less than 3 oppositions

The 29 MAP objects observed at least during 3 oppositions :

Oppositions Mea- Obser- H MPC # MAP H MAP
sures vers

(921) Jovita   6 30 5 10,6 -0,9 9,7
(1444) Pannonia   5 457 8 9,1 2,6 11,7
(9117) Aude   5 36 9 12,4 0,7 13,1
(3904) Honda   4 42 8 11,3 0,7 12,0
(4483) Petofi (Hungaria) 4 19 6 11,9 1,1 13,0
(1166) Sakuntala   4 18 4 8,8 1,1 9,9
(881) Athene   4 12 3 10,3 1,3 11,6
(1353) Maartje   4 12 2 10,4 -0,4 10,0 new measures to do
(927) Ratisbona   3 194 8 9,54 -0,1 9,4 out of MAP; diff.H very small
(1384) Kniertje   3 121 6 9,7 1,7 11,4
(2829) Bobhope   3 75 2 10,3 -0,3 10,0 out of MAP; diff.H < half-variab.
(552) Sigelinde   3 39 11 9,4 0,2 9,6 out of MAP; diff.H < half-variab.
(775) Lumiere   3 33 2 10,4 -0,2 10,2 out of MAP; diff.H < half-variab.
(5641) Mc Cleese (Mars-cr) 3 15 5 12,7 1,4 14,1
(612) Veronika   3 15 3 11,2 -0,4 10,8
(1178) Irmela   3 14 5 11,81 -0,1 11,7 out of MAP; diff.H < half-variab.
(1388) Aphrodite   3 12 4 8,9 1,6 10,5
(6354) Vangelis   3 12 3 11,8 0,5 12,3
(4628) Laplace   3 10 4 11,0 0,3 11,3
(1239) Queteleta   3 10 4 12,5 -0,6 11,9
(453) Tea   3 10 2 10,6 -0,3 10,3 out of MAP; diff.H < half-variab.
(1296) Andree   3 9 3 10,9 0,4 11,3 all measures of the same value
(1656) Suomi (Mars-cr) 3 9 3 12,4 0,5 12,9
(5518) Mariobotta 3 9 4 12,8 0,3 13,1 new measures to do
(4378) Voigt   3 9 3 11,7 0,1 11,8 out of MAP; diff.H very small
(3401) Vanphilos (Mars-cr) 3 9 3 12,6 -0,3 12,3 new measures to do
(3455) Kristensen 3 5 4 12,7 0,8 13,5
(1909) Alekhin   3 5 2 12,3 0,6 12,9 new measures to do
(3873) Roddy (Mars-cr) 3 3 3 12,0 1,1 13,1 new measures to do

The objects marked in orange are those for which the discrepancy decreades under 0.3 mag or about equal to the half-variability

A visual evidence of the reality of high discrepancies of magnitude : (921) Jovita !!
( 0,06 mag of highest half-amplitude for the known lightcurve )

The 20 MAP Objects with the highest discrepancy of magnitude ( difference > 1,0 magnitude ) :

Number, name and group    Diff.H mag  half- Oppo- mea- Obser-   History of Magnitude H
variability sitions sures vers 88-91 92-97 98 and +
(maximum)
(1444) Pannonia 2,6 F 0.29 5 457 8 11.7 11.2 9.7
(1388) Aphrodite 1,6 F 0.25 3 12 4 12.23 11.7 11.7
(6823) 1988 ED1 1,6 F? ? 2 5 3 - 10.7 10.7
(44227) 1998 QP14 1,6 F? ? 1 10 1 - - 17.3
(6911) Nancygreen (Hunga 1,6 F 0.26 2 4 3 - - 13.0
(1384) Kniertje 1,5 F 0.26 3 121 6 11.29 11.25 11.25
(5641) Mc Cleese (Mars-cr) 1,4 F 0.06 3 15 5 - 12.0 12.6
(4440) Tchantches (Hunga 1,4 F 0.16 2 141 5 13.20 12.8 12.9
(5749) 1991 FV 1,4 F ? 2 4 3 - 12.5 12.1
(881) Athene 1,3 F 0.27 4 12 3 10.27 10.29 10.29
(5738) Billpickering (Mars- 1,3 F? 0.23 1 7 4 - 11.1 11.3
(5785) Fulton 1,3 F? ? 1 9 4 - 12.8 12.7
(8021) Walter 1,3 F? 0.04 1 36 3 - - 12.5
(4860) Gubbio 1,2 F? 0.43 1 4 2 - 12.0 12.0
(10772) 1990 YM 1,2 F? 0.65 1 4 1 - - 11.4
(1166) Sakuntala 1,2 F 0.20 4 18 4 14.2 13.0 13.0
(3873) Roddy (Mars-cr.) 1,1 F 0.05 3 3 3 11.8 11.7 11.8
(5026) Martes 1,1 F? ? 1? 3 2 - 11.6 11.6
(4483) Petofi (Hungaria) 1,1 F 0.49 4 19 6 - 10.8 11.7
(7663) 1994 RX1 1,1 F? 0.20 1 91 3 - - 12.7

In the table, one can see that the known half-variabilities are nearly all small with regard to the highest
differences of H magnitudes. These discrepancies of magnitude certainly are mainly due to wrong H magnitudes.

The asteroids only observed at one opposition may be would be have a modification of their discrepancy of H
magnitude.

THE BEST RESULTS OF THE MAP

estimated DIAMETER
Oppositions Mea- Obser- H MPC # MAP H MAP MPC MAP
sures vers in Km in Km

(921) Jovita 6 30 5 10,6 -0,9 9,7 33,4 50
(1444) Pannonia 5 457 8 9,1 2,6 11,7 65 19,9
(9117) Aude 5 36 9 12,4 0,7 13,1 14,3 10,4
(3904) Honda 4 42 8 11,3 0,7 12,0 23,7 17,5
(4483) Petofi (Hungaria) 4 19 6 11,9 1,1 13,0 18,3 11
(1166) Sakuntala 4 18 4 8,8 1,1 9,9 74,5 45
(881) Athene 4 12 3 10,3 1,3 11,6 38 20,7
(1384) Kniertje 3 121 6 9,7 1,7 11,4 50 22,6
(5641) Mc Cleese (Mars-cr. 3 15 5 12,7 1,4 14,1 12,5 6,2
(612) Veronika 3 15 3 11,2 -0,4 10,8 24,8 30,2
(1388) Aphrodite 3 12 4 8,9 1,6 10,5 71 35
(6354) Vangelis 3 12 3 11,8 0,5 12,3 19,1 15,1
(4628) Laplace 3 10 4 11,0 0,3 11,3 27 23,7
(1239) Queteleta 3 10 4 12,5 -0,6 11,9 13,5 18,3
(1296) Andree 3 9 3 10,9 0,4 11,3 28,6 23,7
(1656) Suomi (Mars-cros.) 3 9 3 12,4 0,5 12,9 14,3 11,5
(3455) Kristensen 3 5 4 12,7 0,8 13,5 12,5 8,5

In this list, 4 objects with an estimated size divided by 2 and 1 object increasing its size by 50 % !!
A good result acquired by some amateurs !!
All these asteroids were been observed at 3 oppositions and more and all have a half-variability smaller than
the H discrepancy.

ANALYSES OF THE MAP RESULTS

analysis N°1 : Comparative analysis between the most used observational means from 1997 to 2006

Types of measures

AMv   Visual observations with comparative measures of asteroids
TMx   CCD Observations made with photometric stars of Loneos, Tycho, Hipparcos
UMx   CCD Observations made with USNO stars
GMx   CCD Observations made with stars GSC

NB: Some visual measures made with the USNO or the GSC catalogs are not taken in account

Analysis
1) Computation of the averaged difference on H magnitude for each type of measures and each asteroid
2) Difference by asteroid between the averaged differences of CCD types of measures and the visual ones
taken as basis.
3) Global averaged difference of the 3 types of CCD observations with regard to the visual one
4) Computation of the global averaged absolute value of each type ( no sign + or - ) with regard to the visual
type.

The results of the phases 3 and 4 are summarized in the table below :

MAP Objects taken in account :

The 179 objects ( 2158 measures ) observed at once visually and by one of the CDD types

Results             AMv TMx UMx GMx

Global averaged difference of H mag for the 179 asteroids    0,32 0,27 0,43 0,51
Global averaged difference with regard to AMv ( phase 3 )     0,01 0,14 0,17
Global averaged difference (absolute value) with regard to AMv ( ph.4 ) 0,30 0,27 0,34
Highest individual difference found with regard to AMv   mag 0,82 1,95 1,53

Conclusions

The small difference between the visual observations and those TMx show the acceptable quality of the
visual measures

The increasing global difference of the AMv and TMx measures toward the UMx and the GMx measures
show the increasing inaccuracy of the used stellar catalogs.

The individual analysis of the averaged differences of the TMx show that the errors of magnitude may be
sometimes high (errors on CCD processing), up to 0,8 magnitude

With the experience, yet now, the visual observation is the quickest mean and the less hazardous to
estimate a magnitude in the V band, for an amateur.
Visually, an inacurracy of +/-0,2 mag implicate 5 tenths of magnitude, fan already rather large for a
trained eye
A result at +/- 0,3 mag is rare for an experienced visual observer

Analysis N°2 : Some comparative results betwen the MAP, the Minor Planet Center and Astdys

The website "Asteroids - Dynamic Site (AstTDys)" is specialized in the in the development of proper orbital
of minor planets ( except orbits too chaotic )

The revised H magnitudes of the numbered asteroids of the file "allnum_pro,htm" from Astdys are updated
quarterly, thank's to the new astrometrical measures published by the MPC

Only Astdys and the MAP have lists of revised H magnitudes; It's not the case for the MPC
The 3 entities use the statistical effect to appreciate the averaged H magnitude and to reduce the
inaccuracies ( measures and variability ).

The H magnitudes from the MPC and Astdys are issued from approximate measures joined to the
astrometric data from astrometrists. The measures without indication of color band are assimilated to V
measures. As numerous measures come from R band, some of them are brighter than predicted if they
are assimilated to V
In the MAP, we try to take in account only the "sure" measures or eventually corrected by a standard
deviation ( V-R = + 0.4 by example )

A) Comparisons MPC - MAP :
The corrections of H magnitudes on the NEA by the MPC on the unnumbered asteroids converged on
the same results than the MAP for 8 cases :

H MPC / observations   H MAP   H MPC after adjustment   number Group

1999 RH27 16,5   16,9   16,9     16064 Amor 3
1998 FX2 18,0   18,3   18,2     20255 Amor 3
1998 PG 17,0   17,4   17,3     31345 Amor 2
1998 WS 12,1   12,5   12,5     47035 Mars-crosser
1998 SS49 16,5   15,8   15,8     85713 Apollo 2
1998 QR15 18,5   18,1   18,1     - Amor 3
2000 DO1 20,3   20,4   20,4     - Apollo 1
2001 SG276 17,4   17,8   17,7   - Amor 1

NB: on 28 other objects for which have been used MPC magnitudes for unnumbered objects during the MAP observations :
13 obtained modifications of their MPC H magnitude going towards the MAP H magnitude
15 had no modification of their MPC H or moving away from the H MAP
( NB : For the majority of them briefly bright, the MAP obtained only few measures )

Then there are 21 NEA which constitute 58,3% of the total of 41 MAP objects and for which the MPC
magnitudes joined or approached the H magnitudes from the MAP

B) Comparisons of the MAP with the MPC and Astdys :

Global average of the differences between the H magnitudes
MAP-Astdys 378 asteroids F/0,20
MAP-MPC 416 asteroids F/0,34 higher, because no update by the MPC

Probable reason of the faintness of the MAP magnitudes :
Lack of color bande type for many R measures joined to the astrometric measures received by the MPC, which after didn't revise
the H magnitudes of the objects numbered since 1998 !
The difference with Astdys is fainter, because Astdys periodically rectify the H magnitudes of the MPC

analysis N°3 : Some comparative results between the MAP and the professional or efficient observers

During the last 10 years, few H magnitudes of MAP objects processed independently by the specialists in
photometry.

Some results have been published in 2006, thank's to works on lightcurves :

Oppos. Measur. # MAP H MPC H MAP revis.H Observatory

(4440) Tchantches (Hungaria) 2 141 1,4/F 12,3 13,7 14,0 Simeis MPB 2006-2
(4860) Gubbio   1 3 1,2/F 11,8 13,3 13,3 Warner MAP Message 30/10
(5641) Mc Cleese (Mars-crosser) 3 15 1,4/F 12,7 14,1 14,4  Ondrejov MPB 2006-1

Due to the lack of accurate V-R indexes for these asteroids, the V-R indexes have been estimated to  0.4
magnitude by the concerned observatories
The real V-R index may differ for the majority of the cisjovian belt members of +/- 0,2 mag

The discrepancy of Gubbio seen at v mag 16.0-16.1 was visually detected in October 2006 with a T20cm,
then confirmed with a CCD camera by Brian Warner (CALL) !

analysis N°4 : Impact of the natural variability of the minor planets :

Distribution of 2658 maximum amplitudes of lightcurves on October 15,2006
(photometric database G.FAURE of  October 15,2006)

highest   total of   % on cumul. cumulative %  highest half-amplitude
Amplitude  asteroids    total Total

Less than 0.1 ma 202   8% 202 8%   less than 0.05 mag
0.1x mag 609   23% 811 31%   about 0.05 mag
0.2x mag 571   21% 1382 52%   about 0.1 mag
0.3x mag 423   16% 1805 68%   about 0.15 mag
0.4x mag 286   11% 2091 79%   about 0.2 mag
0.5x mag 177   7% 2268 85%   about 0.25 mag
0.6x mag 118   4% 2386 90%   about 0.3 mag
0.7x mag 62   2% 2448 92%   about 0.35 mag
0.8x mag 61   2% 2509 94%   about 0.4 mag
0.9x mag 53   2% 2562 96%   about 0.45 mag
1.0x mag 23   1% 2585 97%   about 0.5 mag
1.1x mag 29   1% 2614 98%   about 0.55 mag
1.2x mag 13   0% 2627 99%   about 0.6 mag
1.3x mag 9   0% 2636 99%   about 0.65 mag
1.4x mag 9   0% 2645 100%   about 0.7 mag
1.5x mag 3   0% 2648 100%   about 0.75 mag   1 NEA on 3
1.6x mag 2   0% 2650 100%   about 0.8 mag   1 NEA on 2
1.7x mag 3   0% 2653 100%   about 0.85 mag   2 NEA on 3
1.8x mag 0   0% 2653 100%   about 0.9 mag
1.9x mag 0   0% 2653 100%   about 0.95 mag
2.0 mag and mor 5   0% 2658 100%   1 mag and more             all are NEA
Total   2658   100%

The natural variability of the asteroids is not a crucial problem for the MAP because :

1) An asteroid doesn't reach its maximum amplitude of light at each opposition, due to the different
vision angle of this body from Earth, from an opposition to the next one..

2) When it's the case, they are at the maximum or the minimum just during a short time, one time by
entire rotation, the average of the rotation period of the minor planets being about 9 hours

3) It's only the half-amplitude of light which has a possible impact for the MAP
90% of the asteroids with known lightcurves have at most or less than 0.3 magnitude of maximum
half-amplitude !

4) For the 10% of asteroids more variable, the maximum half-amplitude of light is problematic only
during some oppositions, at the moments of maximums and minimums of light...then in average
less than 1 observation made on 6 to 8 !

5) With the computation of the average of all the measures made for an asteroid, the statistical effect
reduces or eiminates the impact of mesures made near a maximum or a minimum of light

Then, the natural variability of the asteroids has generally only a small repercussion on the MAP objects !

The 200 MAP objects for which a lightcurve is known gives un cumulative percentage of 87% for a maximum
half-amplitude of 0.3 magnitude. As the very variable objects often are more easy to detect then the others, the
percentage of half-amplitudes < 0.3 mag is less important for the MAP

THE TOOLS OF THE MAP

MAP ALERTS Published on e-mails by Lawrence GARRETT for 47 actual receivers who are amateur or
professional astronomers
They include news on the last MAP measures and calls for observations for the interesting and
new MAP objects

Registration to :   LSGasteroid@msn.com
or :   gpmfaure@club-Internet.fr

Archives loadable to : http://mysite.verizon.net/lgasteroid/

MAP DATABASE

It contains all the measures made for the MAP, asteroid by asteroid, with a difference of magnitude
averaged by night for all the measures made during the concerned night
Even the rejected measures are present in the database ( waiting for the possible corrections ) but do not contribute
to the results

The minimum to ensure a difference of H magnitude : 3 observed oppositions with at least the contribution
by 3 observers, to permit the average of the possible different averaged H magnitudes of the asteroid from Earth,
during successive oppositions, and to smooth out the personal standard deviations from the visual CCD observers.

A Maximum of measures is needed by asteroid to eliminate statistically the variability and the possible various
errors of the observers

The measures must be made with one of the stellar catalogues and in one light band allowed by the MAP

On December 31,2006, the MAP Database contains 430 asteroids, 4927 individual measures on 3411
lines of averaged measures

Recapitulative list on HTML page loadable at :
http://www.astrosurf.com/map/MAP_DATABASE_recap.htm
http://mysite.verizon.net/lgasteroid/
http://astrosurf.com/aude/map/MAP_DATABASE_recap.htm
Entire Database on zipped Excel file loadable at :
http://www.astrosurf.com/map//MAP_DATABASE_measures.zip
http://mysite.verizon.net/lgasteroid/
http://astrosurf.com/aude/map/MAP_DATABASE_measures.zip

PART OF THE MAP DATABASE ON OCTOBER 17,2006 FOR ONE ASTEROID

TYPES OF MAGNITUDES PRESENT IN THE MAP DATABASE

Magnitude type: The most recommended types of measures are in bold type
AMv  Visual magnitude with asteroid comparison
GMv  Visual magnitude with GSC comparison [Not used for H revision]
UMv  Visual magnitude with GUIDE USNO-A (mag V GUIDE comparison)
UMr  Unfiltered CCD magnitude with USNO A (mag.R comp.) [used for H revision with R-V = + 0.4 mag]
SMr  Unfiltered CCD mag with USNO-SA (mag R comp.)  [used for H revision with R-V = + 0.4 mag]
GMu  Unfiltered CCD magnitude with GSC comparison [Not used for H revision]
LMu  Unfiltered CCD magnitude with LONEOS (notably PGSC) or LANDOLT comparison (mag V comparison)
SMu  Unfiltered CCD magnitude with GUIDE USNO-SA (mag V GUIDE comparison)
UMu  Unfiltered CCD magnitude with USNO-A (mag V GUIDE comparison)
TMu  Unfiltered CCD magnitude with Tycho 2 (mag V comparison) or HIPPARCOS (mag V comparison)
GMR  CCD magnitude with Red filter and GSC (Mag GSC comparison) [Not used for H revision]
UMB  CCD magnitude with Blue filter and USNO-A (mag B comparison) [Not used for H revision]
UMR  CCD mag with Red filter and USNO-A (mag R compar.) [used for H revision with R-V = + 0.4 mag]
LMV  CCD magnitude with V filter and LONEOS ( notably PGSC) or LANDOLT (mag V comparison)
SMV  CCD magnitude with V filter and USNO-SA comparison (Mag.V GUIDE)
TMV  CCD magnitude with V filter and TYCHO 2 comparison or HIPPARCOS (mag V comparison)
UMV  CCD magnitude with V filter and USNO-A comparison (mag V Guide comparison)

Actual total of measures : visual AMv + UMv 1442 measures
CCD Tycho 2 + Loneos 129 measures
CCD USNO 1283 measures
CCD GSC 490 measures

MONTHLY MAP PROGRAM

It includes all the MAP objects visible at more than 4 hours in R.A. from the Sun and at predicted magnitude < V 16,5
Order of the objects by Right Ascension, from + 4 hours East up to 4 hours west to the Sun
Useful for the visual Observers who may plan an observational program for all the night

Example visible at : http://astrosurf.com/map/MAPast.htm
http://astrosurf.com/aude/map/MAPast04-05.htm
Discontinuous update; To ask for : gpmfaure@club-Internet.fr

LISTS OF CONJUNCTIONS LONEOS-MAP

Made by Bernard GUILLAUD-SAUMUR o the AAAA (Association des Astronomes Amateurs d'Auvergne),

Conjunction lists at less than 15' between the numbered asteroids or those of MAP with one of the
34000 stars of the LONEOS catalog ( managed by Brian SKIFF)

1) List by chronological order : list of asteroids in conjonction "Loneos", night after night

2) List by increasing N° of asteroid : list of monthly conjunctions to locate the best nights for the following of a
chosen asteroid

Advantages mainly for the CCD Observers who will do image together asteroids and reference stars
The conjunctions between LONEOS stars and MAP asteroids already are rare. Those between stars and minor
planets of the same magnitude are more rare, hence the exceptional use by the visual observers

Possibilities to predict in advance for a precise night the following of an asteroid lightcurve and/or the obtaining of
measures of accurate measures permitting the verification or the modification of a possible erroneous H magnitude

Lists loadable at : http://www.astrobgs.dyndns.org/astro/MAP/index.htm
or by link on : http://astrosurf.com/map
http://astrosurf.com/aude/map/index.htm

NB: The conjunctions beyond some months are subject to increasing inaccuracies, due to the use of the orbital
elements of the files "MPCORB" from the MPC and then only are indicative

EXAMPLE OF CONJUNCTIONS "LONEOS - MAP" LISTS BY CHRONOLOGICAL ORDER

METHODS AND DEVELOPMENT

VISUAL METHOD

VERY FEW stellar references => Obligation to compare the asteroid magnitudes between them

Basic conditions :

Observations through a sky acceptable, without Moon and not too polluted by human lights
or compensate by a big diameter

Always the use of the same telescope   Minimum 150mm, under a pure and black sky
At least real instrumental limit +14.5-15.0

Always the use of the same powerful eyepiece to obtain always the same light power
for a maximum darkening of the sky
NB: but let Keep a sufficient field and sharp stars

Acquire a good experience in the brightness comparison of asteroids distant the ones from the others

Learn to "gauge the weight" of the light for the 3 last limit magnitudes of the telescope
These are those for which the difficulty of observation increases from tenth to tenth of magnitude.
Learn to estimate a magnitude by its averaged difficulty of visual observation with his telescope and
the useful eyepiece used continuously

Observation method
Préparation :
Choose asteroids if possible successive in R.A. and spreading in predicted V magnitudes, for more
easily comparisons of magnitude
NB: Avoid to choose objects too different in altitude over the horizon, or take in account a difference of
magnitude for the estimation of the observed magnitude

Choose asteroids enclosed by stars nor too bright ( glare ), nor too faint ( difficulties to locate and to plot
both the faint stars and the asteroid )

Prepare star charts for the location of the asteroid and eventually note the known accurate magnitudes
of the neighbouring stars ( rare...)

See, if possible, at the beginning of the observations, an area of faint stars with accurate V magnitudes
to estimate the limit magnitude limite for the night

Observations :
Note the difficulty of observation for the object : "visible directly", "visible slightly indirectly", "rather
indirectly", "well enough indirectly", "well indirectly", "very indirectly","fugitive", "very fugitive, etc...

Estimate the magnitude of the object by the estimate brightness
Indispensable experience with always the same telescope and with the same powerful eyepiece

Indicate the eventual uncertainty of magnitude ( +/- 0,1 in general, +/- 0,2 mag for the contentious cases )

Note the comparisons of brightness between the objects : "asteroid x < asteroid y   of 0,x mag"
or    "asteroid x = asteroid z", etc...

Verify imperatively the motion of the object ( ~ 1 hour later for a cisjovian object ) and do if possible a
second measure of magnitude

Subsequent analysis :
In the report of observations, used also as Analysis table, classify the asteroids by increasing V
magnitude predicted by the ephemerides

Recopy for each asteroid all the "photometric data" noted during the observations :
- precise hours of observations
- estimated magnitude or range of estimation
- level of difficulties to see the object
- comparisons of brightness with other asteroids

Compare all the data and determinate the final visual magnitude(s) of each asteroid,
- by beginning by the objects observed at the predicted magnitude
- by determining at the end the more contentious cases

NB: eventually take in account the great difference of elevation on the horizon for an object
The eventual incertainty must be given ( +/- 0,1 mag in general, +/- 0,2 mag for the contentious cases )

The discrepancies between the observed magnitudes and the magnitudes of ephemerides indicate the
MAP difference ( x,xx mag brighter "B/x.xx" or fainter "F/x.xx" than predicted )

REPORT OF VISUAL OBSERVATIONS DURING THE NIGHT OF OCTOBER 26-27, 2006

USE OF THE CCD MEASURES UP TO 2005

Few accurate reference stars
Calibration on the V band not easy...

No particular method given by the MAP, due to the existence of a great number of softwares and CCD
cameras

Responsibility of each observer to give :
The precise date and hour of observation ( hour and tenths of hour on 5 positions )
The magnitude type, among those used by the MAP
The measure of magnitude itself, with a precision of one tenth of magnitude
The eventual incertainty of the magnitude

Stellar References to use :
In first :  the LONEOS catalog ( including the Landolt, the GSPC and various photometric data )
In second :   the TYCHO 2 catalog ( by using the stars nor too bright, nor too faint, under the mag V10,5 )
Otherwise : the USNO SA2 including yellow stars of magnitudes 11 to 16 (inaccuracy ~0,25 mag)
the USNO A-2 less sure, but the less inaccurate catalog among those covering all the sky

NB : The GSC catalog was quickly rejected, because more inaccurate than the USNO ( about 0,5 mag )
The MAP database contains many GSC measures which sometimes are near GPSC stars. Then, some of
them certainly would be correct for the computation of the H magnitudes of the asteroids. Nevertheless,
the analysis of each case should be made

Catalogues of stellar magnitudes actually used :

Nam   Year of Total of  Limit photometric       Remarks
Catalog issue   included stars mag stellar mag. inaccuracy

Landolt 1982 526 11,5 to 16 BVRI references    also included in Loneos
GSPC 1988 and + ~8900 V 9 to 15 0,05 to 0,1 mag (faint stars also included in Loneos
GSC 2.1 1989 and + 19 millions V 14 to 16 >0,5 mag, to 1 mag and +
USNO-A2 1996/1998 526 millions B and R 19 >0,25 mag, up to -20°  >0,5 mag, more on south
USNO-SA 1996/1998 55 millions B and R 19 <0,25 magnitude   stars of solar type selection
GUIDE + USNO 1996 et + 526 millions B,V,R 19 <0,25 to > 0,5 mag, mag V calculated by Guide
LONEOS 1998/2003 33924 11 to 22 BVRI references
UCAC 1 2000 27 millions R 16 > 0,3 mag   Southern stars
TYCHO 2  2000 2,5 millions V 11 to 12 0,013 to 0,1 mag (faint star
USNO-B 2003 1,04 billion V 21    0,3 mag   downlable on internet
Calsberg Merid.C 2005 95,9 millions r  9 to 17 0,025 to 0,18 mag (faint st.) - 30 to + 50° of declination

In 2001, a great number of unfiltered CCD measures made near the R band were rectified by treating
their averaged difference of H mag with the standard deviation of V-R = +0,4 mag  usually admitted in the
astronomical community
Concurrently, the use of the Tycho catalog increased slowly, with CCD measures more accurate.

DEVELOPMENTS FOR THE INCREASE OF ACCURATE CCD MEASURES

Development N°1

At the beginning of 2006, thanks to the efficient computer help from Bernard GUILLAUD-SAUMUR of
the AAAA association, creation of the :
"lists of conjunctions between LONEOS stars and the MAP objects",
including also many "standard asteroids" ( very faint variability and sure H mag )

Important advantages of these lists :
Possibility to take images including both MAP asteroids and LONEOS stars rather than to do
separately images of asteroids and Loneos stars

Chronological lists :
possibility to know for a precise night what will be the numbered asteroids or the MAP objects which
will be in conjunction with Loneos stars, at less than 15'

Lists by increasing number of asteroids
possibility to search an eventual conjunction between a specific object and LONEOS stars in a month
or the next ones.

Evolution N°2

Statement of failure for the methods of V measures proposed since 10 years ( methods nevertheless
efficient for the professional astronomers and their equipment ), by the small number of measures
generated by the amateurs.

1) Great difficulties with the amateur equipment to obtain many V measures :
"Admited" methods too purist, too much and difficult to implement them for an amateur
Obligation to use fillters absorbing too light
Very few reference stars in the asteroid images made by observers
Possible failuie causes are numerous ( instrument, calibration of CCD cameras, softwares, etc.. )
Lack of time to do numerous and delicate handlings for an amateur during the starry nights which
frequently are rare

2) Too high requirements by the astronomical community for the level of accuracy and for methods
often restrictive :
Due to the emergence of the amateur CCD camera judged wrongly too suited to obtain an easy accuracy
Due to the rejection of the intermediary methods, less acurate, but more effective in results

3)  During these last ten years, the fashion was not the reliability of the asteroid H magnitudes :
The possible discoveries of asteroids and SN by the the amateurs were more exciting
There was a desire to steer the amateurs towards the astrometry, before the start of the automatic
observatories, as LINEAR, LONEOS, etc...
A later reorientation since 2000 was made towards the making of lightcurves, domain judged more
interesting by the professional astronomers and more easy to do only by differential magnitude measures.

4) The MPC was very occupied in doing the increasing number of orbital elements of discovered comet
and asteroids
The computation of orbits rightly is the main goal of the MPC. The accuracy of magnitudes then has a
secondary importance
The interest on the accuracy of the H magnitudes then had no real craze among the observers

In conclusion, the professional observatories with their expensive material have no time to do this type
of basic but important task. Then, it is necessary to permit the amateurs to do this task with methods
adapted to their real possibilities

POSSIBLE ORIENTATIONS FOR THE MAP OBSERVERS

After 10 years of inefficiency of the purist methods "imposed" on the amateurs, it is necessary to test
other alternative methods which would permit more results, with an accuracy approaching the tenth of
magnitude

For the visual observers, the increase of the personal observations by the CCD imagery

Numerous MAP objects with a high discrepancy of magnitude need new observations on successive
oppositions. Then it is necessary to find simple methods getting closer to the visual ones

The possibility to compensate the departure of the first CCD observers in the MAP by doing the two
types of measures

IMPLEMENTATION OF THESE ORIENTATIONS

1) Use the amateur means : economy softwares, sure catalogues and material without filters

2) Loss a minimum of time for the imagery procedures, apart from those strictly necessary, notably
to increase the number of MAP targets during a night of observations

3) Find simple methods of measures and of processes getting closer to the visual ones ( 1 to 2 hours
after observations, and computerizable )

4) Do not go to an academic method, nor to go to a too high accuracy which would reduce the number of
the obtained measures

5) Find tactics permitting to ELIMINATE some causes of difficulties for the obtaining of magnitude
measures :

a) by searching what are the asteroids close to sure reference stars, rather than the inverse
(elimination of the complementary imaging of distant reference stars)

b) by imaging together the asteroids and the reference stars
(elimination of various problems of type airmass, different extinction )

c) by doing preliminary tests on some objects with sure H magnitudes and half-amplitude of
variability < 0,08 mag
(utilisation of a standard adjustement characteristic of the used CCD camera for the inde
for the index R-"r")

d) by finding simple analyses of measures, which would be after computerized
( use of conversion tables for the stellar indexes B-V to V-R )
( building up of a list of real V-R indexes of minor planets from professional
articles and reviews )

Main elements which normally permit to obtain an unfiltered CCD measure equivalent to V
(for stars and asteroids present in the same image)

Mag r  + +/- +/- + + +/- +/- =known +/- = Real
CCD Index V-R differ. Diff.  Extinc- Airmass no Flat various  Mag V Diff. V Mag
star star R-r USNO tion     differ. Tycho 2  Tycho 2 star

sure V mag of asteroid = Mag r   + +/- +/- = sure +/- = Real
CCD Index V-R differ. various mag V Diff. V Mag
asteroid asteroid R-r differ. base Tycho 2 asteroid
asteroid star  Tycho 2

POSSIBLE METHOD IN PROGRESS

Image an asteroid near a star HIPPARCOS, TYCHO ou LONEOS with a sure magnitude, if possible yellow, then
after the observation :

1) measure the unfiltered "r" magnitude of the sure reference star, with the Astrometrica software anf the USNO-A2
catalog     ( important choice of the "Aperture radius" surrounding the star )

2) measure the "r" magnitude of the asteroid, with the Astrometrica software and the USNO-A2 catalog
( same Aperture radius than the star )

3) calculate for the star the difference between R magnitude of Tycho 2 and the unfiltered "r" magnitude obtained by Astrometric
by Astrometrica

4) apply the same difference found to rectify the "r" magnitude of the star

5) apply the standard deviation "R - r CCD camera" of the spectral type of the star, to the asteroid

6) apply the standard type "R - r CCD camera" of the asteroid to rectify its "R"

7) Apply the V-R index of the asteroid (or the standard V-R = 0.4) to obtain the pseudo-"V" final magnitude of the
asteroid

FIRST TESTS MADE (Differences R-r of stars and asteroids not yet processed)

Images made on the "standard" asteroids with very low variability and with a sure H magnitude
( substracted blacks and flats on images of ordinary quality )

AVERAGE OF THE DIFFERENCES "REAL - EPHEMERIDES" MAGNITUDE MEASURES BY ASTEROID

For each imaged asteroid, the average of the differences "Real  - Ephemerides" of V magnitude ( all
measures taken in account ), resulting by the comparison with each star (sure in magnitude) is put in the
column of the spectral type of the star

Legend :
differences of asteroid measures < or ~ 0,1 mag
differences of asteroid measures < or ~ 0,2 mag
differences of asteroid measures > 0,2 mag

ASTEROID 1/2 VAR. real STARS A F G K  R
STANDARD MAX. V-R V-R min = -0,030 0,181 0,345 0,538 0,910
(sure H / var < 0.16)     V-R max = 0,168 0,338 0,507 0,893 2,31
(1) Ceres   0,02 0,41 moyenne     0,08
moyenne     -0,02
moyenne     -0,07
(2) Pallas   0,08 0,36 moyenne   0,11 -0,12 -0,18
moyenne   -0,01
(14) Irene   0,06 0,55 moyenne     0,10 -0,65
(14) Irene N°2 0,06 0,55 moyenne     0,17
(57) Mnemosyne 0,06 0,54 moyenne   0,14 -0,19 -0,05
(75) Eurydike 0,08 0,43 moyenne       0,04
(91) Aegina 0,08 0,45 moyenne       -0,85 -1,26
(96) Aegle   0,06 0,51 moyenne   0,05   -0,24
(101) Helena 0,07 0,57 moyenne   0,03 0,14 -0,84
moyenne   0,11
(105) Artemis 0,08 0,40 moyenne       -0,08
(109) Felicitas 0,03 0,41 moyenne   -0,06
(142) Polana 0,06 0,36 moyenne   -0,39   -0,42
(409) Aspasia 0,07 0,44 moyenne   -0,02
(409) Aspasia N°2 0,07 0,44 moyenne -0,16   -0,38
Average by stellar type = -0,16 0,00 -0,03 -0,36 -1,26

Results
diff. of measure < ou ~ 0,1 mag = 17 59% of good measures
diff. of measure < ou ~ 0,2 mag = 5
diff. of measure > 0,2 mag   7 24% of bad measures

Remarks :
The effect of the difference "R-r" ( not yet treated ) according to the stellar spectral type is visible,
because the big differences especially are on the K and R stars
The measure for the A stellar type is isolated and then is not conclusive
With the exceptions for the asteroids N°57 and N°101, the individual or global "Real-Ephemeride
differences strech for the faintest to the brightest ones, the CCD camera SBIG ST6 being more focused
on the red band
More work is needed on the accuracy of the measures, on the choice of the reference stars and on the
used data to increase the vision in the detail

The Celestron 8 Fastar and the Sbig ST6 camera used for the tests

TESTS AND FUTURE IMPROVEMENTS

Current contacts with Richard MILES, the Chairperson of the British Astronomical Association and a
specialist in CCD photometry for the amateur equipments

Find the standard deviation by spectral type of star for the SBIG ST6, in the R band

Apply the difference "R-r" to the stars and to the asteroids

Collect sure data concerning the real V-R color indexes of the asteroids and the conversions B-V and V-R

Image again standard asteroids to do better measures and to reduce the differences

Continue to analyse the acquired CCD measures for the detection of the frequent causes of errors

CONCLUSIONS

It is necessary to observe the objects with magnitude discrepancies x times on x oppositions to reach
the sufficient number of oppositions and measures ( through the individual measures or the lightcurves ) pour
permitting the validity of an averaged H magnitude. Then the task is gigantic !

The visual observers actually are too little numerous and those using CCD cameras almost non-existant
Then, the MAP needs new volunteers for the increase the number of the visual and CCD measures !

For these future goals, the actions seem to be :

- make the visual observation and its creditable results known

- finalize a simple method to obtain amateur unfiltered CCD measures permitting the obtaining of results
similar to the V band and reliable to at least 0,1 mag

- find the response deviation of the CCD cameras in relation to the V and R bands

- Find volunteers with a different CCD equipment to do tests and measures

- Collect sure data on the real V-R color indexes of the asteroids and the conversions B-V and V-R

- Continue to analyze the CCD measures to increase their accuracy

- Publish the MAP results and analyzes with the hope that one day the MPC may include our data and
rectify the erroneous H magnitudes of the numbered minor planets

Thank you for the interest in this article and in the MAP.
Thank you also for all the eventual good ideas and the futures willingnesses !
Thank you at last to Lawrence GARRETT for his revision of this article and to Richard MILES for his
advices on the CCD tests made in the MAP

SEE YOU SOON MAY BE AMONG THE MAP MEMBERS ....

Gérard FAURE

Gérard FAURE     mail adress gpmfaure@club-Internet.fr
Files of analyses

Lawrence GARRETT   mail adress LSGasteroid@msn.com

AUDE - MAP Page on the website   http://astrosurf.com/map/
MAP Database, Photometric Base (data December 2006) + various records on asteroids
http://astrosurf.com/aude/map/index.htm

MAP site web         http://mysite.verizon.net/lgasteroid/
MAP Database and photometric list (data December 2006)

ALPO Minor Planet Section site web   http://www.lpl.arizona.edu/~rhill/alpo/minplan.html
MAP Database and photometric list (data December 2006)

Bernard GUILLAUD-SAUMUR    http://www.astrobgs.dyndns.org/astro/MAP/index.htm
Conjunctions "numbered asteroids - LONEOS stars"

Asteroids - Dynamic Site (AstTDys)   http://hamilton.dm.unipi.it/cgi-bin/astdys/astibo

Minor Planet Center