MINOR PLANET FAQ's

Minor Planet Center Code 740
SFA Observatory

Answers to Frequently Asked Questions


The following are some questions and answers from the Minor Planet Mailing List {MPML}.

What proportion of asteroids found each year are found by an amateur astronomer versus a full-time professional astronomer?

Some statistics from the past few years:
Year  #Disc  #Prof   #Amat    % Amat
1996   8745   6680    1322     15.1
1997   9974   9050    1973     19.8
1998  28427  26769    1811      6.4
1999  19698  19674    1572      8.0
Overall, amateurs have 13177 out of 159167 discoveries (8.3 percent).

The value for 1999, currently 8.0%, is comparable to the long-term average. As promised last month, here are counts on the total number of professional and amateur discoveries, with a break down by year (since 1980) and by country (indicated by two-letter codes). The statistics for 1999 are complete through the 1999 May 4 MPCs. Apologies for the width of the output, but I wanted to show the totals for a wide range of countries.

Year # Pro #Amat    US    IT    JP    UK    AU    FR    DE    CA    PT    SI    SK    MX    ES    AT    CH 
1980  2095    11     0     7     4     0     0     0     0     0     0     0     0     0     0     0     0
1981  3474   288     0   286     2     0     0     0     0     0     0     0     0     0     0     0     0
1982  2316   344     0   339     5     0     0     0     0     0     0     0     0     0     0     0     0
1983  1401   166     0   164     2     0     0     0     0     0     0     0     0     0     0     0     0
1984  1469    35     1    33     1     0     0     0     0     0     0     0     0     0     0     0     0
1985  1772    23     0    22     1     0     0     0     0     0     0     0     0     0     0     0     0
1986  2593   131     0   123     8     0     0     0     0     0     0     0     0     0     0     0     0
1987  2585   132     0   126     6     0     0     0     0     0     0     0     0     0     0     0     0
1988  2029   441     0   426    15     0     0     0     0     0     0     0     0     0     0     0     0
1989  2723   600     1   576     7    16     0     0     0     0     0     0     0     0     0     0     0
1990  4185   645     0   640     2     3     0     0     0     0     0     0     0     0     0     0     0
1991  4550   723     0   714     4     5     0     0     0     0     0     0     0     0     0     0     0
1992  3837   885     0   883     2     0     0     0     0     0     0     0     0     0     0     0     0
1993  6195   670     0   622    48     0     0     0     0     0     0     0     0     0     0     0     0
1994  5299   948     6   800   140     2     0     0     0     0     0     0     0     0     0     0     0
1995  7356  1187    28   960   156    25     0     0     2     2     0     0     0     0     0     0     0
1996  8699  1329   271   801   165    26    11     0     2     4     1     0    18     0     4     0     0
1997  9940  1994   365  1157   225    20    40    53    35     0     0    11    36     0    45     0     0
1998 28338  1850   285   586   215     4   203    49    52     0     0     1    48     6    21     1     1
1999  7461   972   140   311    62     0    71     2    14     5     0    11     9     8     6     0    12

          Total   1231 10490  1074   102   325   104   105    11     1    23   121   14    76     1    13

Total number of professional discoveries = 144901
Total number of amateur discoveries =  14427
Some remarks: Overall, the percentage of amateur discoveries is 9.1 percent. The rate obviously varies from year to year (from a low of 0.5 percent in 1980 to a high of 18.7 percent in 1992), but since 1988 the percentage has rather consistently been above 10 percent. Since 1988 the total number of amateur discoveries has increased five times, to 1997/1998 totals nearing 2000/year. This is comparable to the professional discovery rates through the late 1980s. For much of the 1980s the principal amateur effort was in Japan. The number of Japanese discoveries peaked in 1997. Amateurs in other countries got involved generally following the introduction of affordable CCD technology, although the U.K. did manage 24 photographic discoveries in 1989-1991. Italian amateurs, although discovering at a low rate in the 1980s, really got going in 1993. The U.S. followed suit in 1994, with Canada, Germany and Slovakia starting in 1995 and Australia (principally) in 1996. Overall, Japanese amateurs account for almost 77 percent of the amateur discoveries since 1980. This percentage is falling as the Japanese activity slackens and the activity in other countries rises. If 1999 continues at the rate of the first 4.something months, the number of amateur discoveries this year may approach 3000.
Gareth V. Williams, Associate Director, IAU Minor Planet Center

I keep hearing and reading this: "More people work in a single McDonald's restaurant that are employed worldwide to monitor asteroids." Is this really accurate?

I don't know how many people work in a typical McDonald's. I avoid getting to such place if I don't have to. For the number who work on asteroid searches, as usual it depends on how you count. It can be made relatively quickly, and hopefully accurately.
If we take into account the people who are paid to discover asteroids, i.e. not follow up, just run the machine at night, hoping I do not forget too many people:
Spacewatch : At the last count, there were 12 people on payroll for the whole program (including stellar program), but maybe 4 observers
LINEAR : There are 5 people counted as observers, 3 more as measurers
LONEOS : 5 people maybe (Koehn, Skiff, Ferris, Levi, ???)
NEAT does not seem to observe currently
ODAS does not observe currently
Catalina : 4 if I am right (Larson, Hergenrother, Spahr, and ... ?)
SCAT (Beijing) 4 persons if I am right, but asteroid program is only a small part of the telescope use. So one person full time is maybe right. So we are talking about 20 persons. Good nights, Alain
LONEOS has two full time equivalent positions. Spacewatch, LINEAR, CATALINA, and NEAT are the other "professional" US NEO searches. They have slightly more full time positions. But even if we average 5 FTE positions, that is only 25 people in the US. It is harder for me to quantify the international effort but I bet it is less. A single Mickey D's has how many? Of course, lots of others do this job for no pay. Very few people work at Mickey D's for no pay. Regards, Bruce
I have a feeling that I am the only person in full time employment in the southern hemisphere directly for NEO work. So it is certainly true for the southern hemisphere! Regarding multiple observations in Vaisala, this query was probably the result of my comment in comparing extrapolation vs Vaisala. If a "best fit" to several observations is made by linear interpolation in order to extrapolate the path, then the Vaisala orbit will only be comparable if (two) observations are used that are in exact agreement with the interpolation. One must thus create the two input observations for the Vaisala orbit from the interpolation, preferably at the times of the extreme observations. Cheers, Rob Robert H. McNaught rmn@aaocbn.aao.gov.au
Because of repeatedly hearing this, last time I was in the McDonald's in Sierra Vista, I asked the manager how many employees the store had. (Sierra Vista is a town of 40k people.) The answer was 155, much larger than I expected. Now, as Alain said, I suppose it depends how you count asteroid folks. -- Jeff Medkeff , Hereford, AZ ,

Where can I find information on the method of Vaisala for orbit calculations?

"The Determination of Orbits" by A. D. Dubyago, The Macmillan Company, New York, 1961.

MPC's New Object Ephemeris Generator uses Vaisala's method.

Check out this Vaisala Method of Orbit Determination Excel Worksheet.


Brian Marsden descirbed a variation of the Vaisala method mentioned in Dubyago in an article in Asteroids I (edited by Tom Gehrels). In effect, you try, as David Tholen suggested, various combinations of eccentricities and mean anomalies. The combination needs to give results within certain parameters (I've forgotten them). For each solution, you check the residuals against the observations at hand and take the one that gives the best agreement. I've done some code along these lines but don't claim it to be the most accurate in the world. However, it has served to find targets a few days later and fairly close to where predicted. Clear Skies, Brian Warner 716 Palmer Divide Observatory Colorado Springs, CO

Online References


Dan Bruton
astro@sfasu.edu
Minor Planet Research