The International Astronomical Union Minor Planet Center

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Guide to Minor Body Astrometry

This guide is intended for those observers interested in observing minor planets, comets or natural satellites of planets, and reporting those observations to the Minor Planet Center.
Please use Jira for any questions or feedback.

How do I begin?

How do I report observations to the MPC?

The observation format requires an observatory code. If don't have it, you should apply for one.

What are some common mistakes?

How many nights should I report?

What about new discoveries, discovery credits and naming?

MPC processing

Others

What equipment do I need?

Almost any type of telescope will do (reflector or refractor).You will need to know the focal length of your telescope and the physicalsize of your CCD's pixels to calculate the pixel scale. Your setup shouldbe such that the pixel scale is no greater than 2"/pixel (preferably) or3"/pixel (at worst). In practice, your optimal pixel scale is somethingthat you will have to determine for yourself, taking into considerationthe capabilities of your telescope and CCD and the seeing at your site.If your pixel scale is much larger than the values quoted above, then thequality of the astrometry will suffer. If your pixel scale is too low foryour local setup, then the signal-to-noise of the images may be low aseach image is spread over a large number of pixels.

You will also need a computer to capture the images and software toperform the reductions. Various software packages are available toprocess the images. We suggest you consult theMinor Planet Mailing Listfor information about the lastest popular software.

An accurate clock/watch set to Coordinated Universal Time (UTC)is a must and this must be checked regularly (as a minimum, at the start ofeach observing session) against areliable standard.

Access to e-mail is also important, both for reporting observations toand receiving designations from theMinor PlanetCenter (MPC).

What sort of CCD should I use?

It is not our place to recommend specific brands of CCDs. A look throughany popular astronomy magazine shows that there are a variety of CCDsavailable. The CCD that is right for you depends on your computersystem and on how much you want to spend. CMOS sensors are also now available and their performances seem to be very good especially for fast moving objects.

How do I make measurements?

The exact details of how you will make measurements on your images andperform the reductions will depend on the software package you are using.In broad terms, you will determine pixel x,y for the centers of a numberof comparison stars of known position (at least three comparison stars,preferably as many as are on the image) and the minor bodies in each image.Using these x,y measurements (determined to a fraction of a pixel) and thecomparison star coordinates (taken from a suitable reference catalogue[see below]), the program should thendo a least-squares plate-constants (LSPC) solution to derive the unknowncoordinates of the minor bodies. Be suspicious of any package that doesnot do a proper LSPC solution!

You must not attempt to derive positions by overlaying charts on yourimages or by estimating positions by eye. The accuracy of these positionswill not be sufficient.

The MPC also encourages submitters, especially those searching through archival astrometry, to carefully examine any marginal detections. Astrometry should be reported only for detections with a sufficiently high signal-to-noise ratio to withstand external independent review of the images. We note that synthetic tracking software, such as Tycho Tracker, often requires significant experience to avoid submitting stacked noise in sky location of the expected position of an object.

Where should I obtain my comparison star coordinates?

Most CCD fields tend to be rather small (a few tens of arcminutes wide) andthis has in the past precluded the use of traditional standard astrometriccatalogues. Fortunately, the situation is now much improved and mostastrometric software allows suitable catalogues to be queried over thenetwork (e.g., from sources such as Vizier) or from a local copy.

It is the recommendation of the Minor Planet Center that observers should migrate to using theGaia catalogues (DR2, DR3 and future ones). Other acceptable catalogues include UCAC4 and UCAC5.

The following sources MUST NOT be used for comparison-star coordinates:

The World Coordinate System information in the FITS headers for images in the Digital Sky Survey (whether accessed via the Web or via the highly-compressed CD-ROM version).
Any B1950.0 star catalogue (e.g., SAO Catalogue).

What corrections should I apply to the derived positions?

None!
No corrections should be made by the observer for parallax and noattempt should be made to correct the UTC times of observation to TerrestrialTime (TT), the uniform timescale used in orbit computations.

How do I obtain an accurate time?

Getting an accurate time when measuring astronomical images is extremely important(see the paper by Farnocchia et al (2022) containing the results of the firstIAWN campaign).
Note that the determination of an accurate time for an observation depends not only onhaving access to a reliable standard, but also by understanding the delays in the observingsystem.

The first step consists in obtaining the current UTC from theU.S. Naval Observatory's Time Service Department
Then we suggest observers to regularly check their estimated observation times against GPS satellites. For more information about how to do it, please see the page'Calibrating timing of astronomical images using navigation satellites' on the Project Pluto website.

What objects should I be observing?

Those observers who wish some guidance on what objects to observeare advised to check out the MPCNEA Planning Aid,Observer Target List orObservable-Object List Customizer.
Other services are also available, such asNEOfixeror thePriority List from ESA.
Some observers have set up their own web pages, generally to encouragefollow-up of their own discoveries. We havecollected together some of these sites, but if you wish to be added to the list, please let us know throughJira.

Ephemerides for minor planets can be generated using theMinor Planet Ephemeris Service.

How do I get an observatory code?

Observatory codes are intended for "permanent" (repeated usage) observing sites. It is not necessary that your telescope is associated with any existing building in order to apply for an observatory code; setting up your portable telescope in your backyard is permanent enough to obtain an observatory code from the MPC. We encourage all observers to apply for an observatory code. The"Roving Observers" format should only be used in very specific cases by observers at temporary sites, preferably only by people with prior experience submitting measurements to the MPC.We always encourage observers to apply for an observatory code and not to use the Roving Observers format.

When you apply for an observatory code, you must complete the following tasks, preferably on the same day:

Complete and submit thenew Observatory Code Request Form.
Submit in a single submission astrometric measurements meeting the requirements listed below.

Your observatory code request will not be processed untilboth the request form and qualifying measurements are received.Please submit your request and the necessary astrometric measurements close in time; do not submit one if you are not ready to submit the other.

Your astrometry measurements must meet the following requirements:

You need to submit measurements of at leastten numbered Near-Earth Asteroids; theObserving Target List can be used to identify NEAs visible from your location.
Youmust not include measurements of comets, natural satellites or objects that have yet to be numbered.
Every object included must befainter than 16th magnitude.
Every object must be observed ontwo distinct nights, preferably less than a week apart.If weather interferes, the two nights can be some weeks apart. However, do not submit partial astrometry (or your request form) until you have obtained everything you need; submit everything at the same time.Note: The ten objects do not need to all be measured on the same two nights.
Three to five observations of each object from each night should be included.Do not report single positions per night; single positions will cause your entire submission to be rejected.Reporting more than five measurements in a single night is generally not useful for constraining an orbit.
At least one measurement of each object in each nightmust include a photometric measurement of the object's brightness, i.e. the apparent magnitude.
Use observatory code XXX in the observation header and measurement lines when submitting measurements towards an observatory code request.Donot use any other code, as doing so may cause your submission to be processed incorrectly or be rejected.The observatory code XXX is specifically for measurements supporting an observatory code request; please do not use XXX once you have been assigned a real observatory code.
The header of your submission must include a comment line with content formatted like this example:
```
 Long. 123 45 67.8 E, Lat. 12 34 56.7 N, Alt. 123m, Google Earth
```
Where the longitude, latitude, altitude and source should be the same values as you provide in the observatory code request form.
Observations can be submitted in either ADES or MPC1992 80-column format.The older MPC1992 format is obsolete and being replaced by ADES.We therefore encourage all observers to get used to submitting measurements in the ADES format before support for the 80-column format ends. Please follow the instructions documented on theADES Data Submission page for details on how to prepare and submit your measurements in ADES format.

Note that if your astrometry submission has severe problems (such as formatting errors, duplicate lines, single positions within a night, missing mandatory header fields, etc.) the entire submission gets automatically rejected and you may not get an e-mail about it. If you did not receive an acknowledgement email and you cannot find your measurements using theWhere Are My Observations (WAMO) service, then your submission must have failed. In such case, please review your submission file to identify the problems, reviewthe submission instructions and try again.If you cannot identify the problem, you can ask for assistance in the helpdesk ticket tied to your observatory code request; simply reply to the email that you received when you submitted the observatory code request form (it will be from "General Support" and will have "MPCHLP" in the subject line).

The new observatory code request form requires you to provide the following information:

A contact name.
A contact email address. It is important that youuse the same email address for both the request form and the astrometry submission, so that they are automatically linked. Using different emails will result in longer processing times.
An observatory name. Optional, but if not given, the city/town name will be used.The observatory name must not contain the name of a living person.
The observatory site. Name of nearest city, village, neighborhood, mountain, forest, etc.
The country the observatory is located in.
Latitude, indegrees, arc-minutes and arc-seconds (including one or two decimals) (not decimal degrees) N or S of the equator, in the WGS-84 system, eg.42 22 53.31 N or42°22'53.31"N.
Longitude, indegrees, arc-minutes and arc-seconds (including one or two decimals) (not decimal degrees) E or W of the Greenwich meridian, in the WGS-84 system.Do not use negative longitudes. Give a longitude as either:
- a specific number of degrees, arc-minutes and arc-seconds E or W (being sure to state which direction) of the Greenwich meridian, eg.71 07 42.15 W or71°07'42.15"W;
- a specific number of degrees, arc-minutes and arc-seconds E of Greenwich (according to the IAU convention).If a site is just west of the Greenwich meridian, give the longitude as a quantity near 360°, not as a negative quantity, eg.288 52 17.85 E or288°52'17.85"E.
The latitude and longitude must be given with a precision better than one arc-second, ie. the arc-second values must have a decimal.Do not report coordinates with integer arc-seconds; that corresponds to a precision of several tens of meters on the surface, which is insufficient. Here are 3 possible ways (others exist) to obtain precise coordinates:
- Google Maps: find your observatory, and right click on it.Click on the decimal degrees numbers (usually at the top of the menu), paste that into the search bar and hit return.Google Maps now converts that to the desired degrees, arc-min, arc-sec format, with one decimal on the arc-seconds.Simply copy the-reformatted value from the search-bar.
- Google Earth: find your observatory on the map, and right click on it.Click "Copy coordinates", and paste them into the search bar; unfortunately, this gives coordinates of insufficient precision (no decimal on the arc-seconds).Manually add decimal values (.1, .2, etc.) and click return, and repeat using trial and error until the search pin lands exactly on top of your observatory.
- GPS unit/app: Record several measurements, preferably over the course of several days, and take the average value.If possible, hold the GPS unit as close as possible to the location where the telescope's two axes intersect.
Altitude, which must be measured inmeters above mean sea-level (unless measured with a GPS). Google Earth gives altitudes relative to mean sea level. GPS units vary, but typically have an option to display altitude above mean sea-level (if not, see below).
The height of the telescope above ground (or wherever else 'altitude' is measured), in meters to the nearest whole meter. Leave this as 0 if the altitude provided corresponds to the height of the telescope, otherwise fill this value with the difference between the location where the telescope's two axes intersect and the location the 'altitude' refers to (typically ground level).
The source for the specified coordinates and altitude (e.g., Google Earth, GPS, named map, etc.). If you measured your altitude using a GPS (or GPS app), you must select "GPS" and the correct option from the "Reference frame for altitude" drop-down box, where "EGM-96" corresponds to an altitude above mean sea-level and "WGS-84" corresponds to an altitude above the reference ellipsoid.

When you submit your observatory request form, you will receive two emails:

one from "new_obscode_request" with subject line "New obscode request by Your Name"; this simply contains a copy of the information that you entered in the form.Do not reply to this email.
one from "General Support" with subject line "MPCHLP-???? New obscode request by Your Name" (where ???? is a number).Do not delete this email andmake sure it is not in your spam folder. This email thread is tied to your observatory code request. If we need to contact you about your request, we will reply to this email thread. Once your observatory code is assigned, we will let you know through this email thread. If you want to contact us about your request, you can reply to this email thread as well, simply reply above the dashed line and without altering the subject line.

A few additional notes:

The longitude and latitude must be specified to a precision of 0.1 arcsecond or better.A useful tool for determining your site's coordinates isGoogle Earth.Note that we now use Google Earth to verify the given coordinates. If we have a query as to the location, we may ask for clarification/confirmation.
If you do not use Google Earth, it is important to note that the longitude and latitude that you supply must be geographic coordinates, not geocentric coordinates.
An observatory code will typically not be assigned if your astrometry shows large post-fit residuals (in coordinates, time or magnitude) or in other ways indicate poor quality. Such observations will be rejected and new, better, measurements will have to be provided in order to obtain an observatory code.
The assignment of new codes is done manually in batches, usually once per week.If more than two weeks have passed since your submission, please contact us by replying to the "MPCHLP" email that you received when you submitted your request form.
If you fail to supply sufficient measurements in your initial submission, fail to supply all required information, or your initial measurements are not of sufficient quality, an observatory code will not be assigned and we may contact you for additional information/measurements.We will only contact you if you have submitted the observatory code request form; we will not contact you if you have only submitted measurements.
Even if you are only interested in comets, it is required that you follow these guidelines and not submit comet astrometry until you have successfully obtained an observatory code.
For new observatory code requests with coordinates very close to an existing code, we may ask for additional information, or we may require additional evidence that separate observatory codes are necessary (we may, for example, request that you submit additional NEO measurements).

If any of the previous conditions are not met, the obscode will not be assigned.

If something is not clear or you don't know why your data have been rejected, please open aHelpdesk ticket (or reply to the existing one tied to your observatory code request, subject line includes "MPCHLP") before trying to send more data to us.

Does my observatory code move with me?

No, your observatory code does not move with you. Observatory codes are tied to a specificlocation relative to the center of the Earth (exceptions apply to "Roving Observer" and artificial satellite codes).If you move your observatory to a new site, you have to apply for a new code. If you go and observe at a friend's observatory, you must use their observatory code (applying for one if necessary) rather than using your own.

I built a new telescope near my old one; do they need separate observatory codes?

Maybe. It depends on the distance, the resolution of your telescope and what type of objects you observe.Telescopes using the same observatory code should never be more than 100 meters apart.However, if you intend to ever observe objects onthe Near-Earth Object confirmation page (NEOCP), or intend to observe GPS satellites to calibrate your system clock, or for other reasons hope to observe objects very close to the Earth, closely spaced telescopes are more likely to require separate observatory codes.Telescopes can typically use the same obscode if they are less than X meters apart, where:

 X [meters] = Y / D [meters]

where D is the diameter of the largest telescope, in meters, and Y varies as follows:
Use Y=6 if you intend to observe GPS satellites in order to calibrate your system clock and know the time of your measurements to the best possible accuracy.
Use Y=6 as well if your setup is able to routinely observe high-priority NEOCP objects, including potential impactors,within hours of the object being posted to the NEOCP.
Use Y=15 if you will only occasionally observe NEOCP objects.
Use Y=30 if you are not interested in observing NEOs and will primarily observe distant objects like Centaurs and Trans-Neptunian Objects.

Telescopes smaller than 50 cm (0.5 m) in diameter thus typically do not need separate observatory codes if they are all within 30 meters of each other, due to the limitations of their resolution.Telescope hosting facilities (where many privately owned small telescopes are hosted mere meters apart) can therefore consider applying for a single observatory code that all users of the facility can use; such a shared code should use a coordinate close to the center of the cluster of telescopes.

For new observatory code requests very close to an existing code, we may ask for additional information, or we may require additional evidence that separate observatory codes are necessary (we may, for example, request that you submit additional NEO measurements).

How do I update the information associated with my observatory code?

If the information relating to an observatory code needs to be updated/corrected, simply raise aHelpdesk ticket about it.Please note that if your observatory has been moved to a different site, youcannot simply change the associated coordinates to the new location; you must apply for a new observatory code for the new site.However, many obscodes were assigned based on low-precision coordinates; many have recently been found to be wrong by tens or even a hundred meters.If you have measured, either using Google Earth or a GPS, the location of your observatory more accurately and precisely than the coordinates the MPC currently use, we highly encourage you to contact us with such updates. Additionally, if you wish to change the name of your observatory, or change the contact person/email address, this can also be changed by opening a Jira ticket.

When reporting a change/update, please use the following format, to make our lives easier (a few lines have comments starting with a #; don't include that part):

observatory_code: ???  # The observatory code that you want to updatecontact_name: New Contact Nameemail_adr: new_contact@email.comobservatory_name: New Observatory Nameobservatory_site: Updated Site Nameobservatory_country: Updated Country Namewebsite_url: https://newobservatoryname.urlamateur: True/Falseobservatory_lat: ?? ?? ??.?? N/Sobservatory_long: ??? ?? ??.?? E/Wreference: Google Earth/Google Maps/GPSobservatory_alt: 0  # Integer metres altitude of ground leveltelescope_height: 0  # Integer metres above ground levelreference: Google Earth/GPSgps_ref_frame: WGS-84/EGM1996/EGM2006/Mean sea level

You only need to report the fields that you think need to be changed. You do not need to guess at values for fields you do not want to change; simply do not include those lines.

Are there any restrictions on my observatory's name?

Yes and No.
No, in the sense that we cannot dictate what you choose to call your observatory.
Yes, in the sense that we don't have to use your observatory's name in theMPCs if we don't think it is appropriate.Proper names or names of living people should not be chosen as site names.If your observatory's name is longer than 35 characters, please also suggest an abbreviated version, as long names cannot be used in all contexts.

Please be careful when you select your site name.

How do I begin?

Please follow these rules:

If your site does not have an observatory code,ask for it!
If possible, report at least three observations of each object from each night: do not report single positions per night. As a general rule, batches that contain single positions will be returned in their entirety to the submitter.
You should not start by observing fast-moving objects. It is important that you gain experience by observing "routine" objects before attempting to observe "unusual" objects. We also expect you to prove that you can produce good astrometry of known objects before you begin to discover new objects.
In general, comets are harder to measure than minor planets. If we have a new observer reporting comet observations of bad or indifferent quality we do not know if it is simply a problem due to the comet (big, bright difficult-to-measure image) or a problem with the measurement/reduction process.
The MPC encourages submitters, especially those searching through archival astrometry, to carefullyexamine any marginal detections. Astrometry should be reported only for detections with a sufficientlyhigh signal-to-noise ratio to withstand external independent review of the images. We note that synthetictracking software, such as Tycho Tracker, often requires significant experience to avoid submittingstacked noise in sky location of the expected position of an object.
Reporting magnitudes is optional, but highly desirable. Please try to report magnitudes if you are submitting archival astrometry.
MPC encourages observers to use the correct keywords in the observational header, particularly when itcomes to rapid processing of NEOs or comets. Without the correct keyword, tracklets could end up in awrong or slower queue. In addition, please submit new NEOs separately from NEOCP followup and/orincidental astrometry. Lastly, please follow the instructions on how to format other elements of the header. Issuessuch as omitting space between initial and last name slows down the process of the submitted astrometrysince the automated program code assignment will not be possible (follow the istructions reported on the how to specify observational details page).
In particular:
- Batches containing observations of new NEO candidates must have "NEO CANDIDATE" in the subject line.
- Batches containing observations of objects already on the NEOCP must have "NEOCP" in the subject line.
- Batches containing observations of new comet candidates must have "NEW COMET" in the subject line.
- Batches containing observations of new TNO candidates must have "NEW TNO" in the subject line.
See'How do I report my astrometry?' to understand what format you need to use to report your observations.
See also'What quality of measurements should I aim to produce?'.

How do I report my astrometry?

Astrometric observations can be reported in two different formats:

The longstanding 80-character MPC1992 format (also informally called obs80)
The more recentIAU Astrometric Data Exchange Standard (ADES).

Observations reported in the MPC1992 format needs to follow the rules detailed on thepage describing the format.Please read this document carefully and report the observations in the correct format.
Observations reported in ADES format needs to follow the rules described in theADES documentationsand on the MPCMPC ADES Data Submission page.

Observations of minor planets, comets and natural satellites, formatted as specified in thelink above, can be reported via:

E-mail toobs@cfa.harvard.edu (MPC1992 only)
Observation Submission Forms (ADES only):
- ADES XML Submission Form
- ADES PSV Submission Form
MPC1992 cURL instructions

In addition to the above points, please also check the following notes:

Do not report more than one position for each time of observations. Observationsof objects that contain multiple positions for a single time of observation will bereturned to the submitter for correction.
When there is no trailing of the minor planet image (or you are measuring the middle of a trail) the time of observation is the mid-exposure time. If you are measuring both ends of a trail, then one end is associated with the start of the exposure, the other with the end. Alternatively, if the trail is very short, you can simply report the mid-point. However, you must not report both a trail-end and mid-point measures from the same trail.
Note that reported magnitudes must be derived from the individual frames: do not obtain a magnitude from one frame and then copy it on all the other observations. Also, ensure that you report the magnitudes with the astrometry: do not say "Photometry to follow".
Always report positions for every moving object in your images. Do notassume that just because an object is numbered that continuingobservations are not important. The inclusion of well-known objects,particularly when there are also observations of unidentified objects,serves as a useful check of the quality of your measurements.

What's the ADES format?

The Astrometric Data Exchange Standard (ADES) format was quite recently adopted by the IAU (August 2015). It was introduced with the goal of standardize the exchange and the storage of astrometric data (observations and uncertainties) and their associated data description between observers and orbit computing centers. The MPC not only accepts and internally uses observations in this format.
Details are available on theADES GitHub repository and on theMPC ADES webpage.

The use of the ADES format is not mandatory at the moment, but the MPC strongly encourage users to familiarize themselveswith the format and the repository.

How many observations should I make of each object?

As a general rule, when pursuing high precision astrometry, it is preferable to obtain small quantities ofdeep, high SNR data.

The MPC typically recommends taking a few observations over a period ofan hour or so per object, per night. Additional astrometric positions are typically not helpful for thedetermination of the orbit.
Observations of specific objects are best made on pairs of nearby nights as the accuracy of isolated single-night observations can be difficult to judge. By observing on pairs of nights any ambiguity is removed.
Please try to not make only one observations of each object per night. Without specific appropriate reasons, if a batch contains any single positions, the entire batch will not be accepted and it will be returned to the sender.
Observations of a potentially new object in groups many hoursapart on a single nightcan be useful in particular in the case ofa newly-discovered object that may be close to the earth.

However, we recognize that there might be cases in which more observationsare needed, e.g. for photometric purposes, or for an object during a close encounter with the Earth. Eventhough the MPC always encourages the acquisition of high quality astrometry, we emphasize that it is notour place to discard large numbers of observations when they get sent to us. There will be cases inwhich objects are going to have hundreds of published astrometric and photometricmeasurements. While the MPC already de-weights these measurements for our orbit fits, it is upto the end user to decide what they want to do with them.

What quality of measurements should I aim to produce?

Astrometry is a field where bad measures are generally of littleor no use. It is important that observers can consistently produceobservations with a consistency of <1" for observations using thesame comparison stars, and a night-to-night consistency limitedonly by the comparison star catalogue.
A few additional notes:

Please check if you have any timing errors before submitting observations (see the'How do I obtain an accurate time?' point.)
Please note that if you are using theADES format, you are also able to report your astrometric uncertainties. Be sure you have read how to compute and submit your uncertainties in theADES documentation.

Can I report approximate or preliminary measures?

No.
Approximate measurements will be ignored.Only report final astrometry.
Don't report preliminary measures andthen improve them. It is very time-consuming to replace preliminarymeasures.

Do I need to identify objects?

You do not need to identify objects, but we suggest you do it if you can.All the observations will be validated anyway through orbit fitting.
If you do not identify the object, the MPC checking procedures will first check if the object can be linked to any known solary system objects before processing it.
However, every reported observation must have a designation. If you don'tknow the designation of a particular object, or are not bothering to identifyobjects, use an observer-assigned temporary designation. Observer-assigned temporary designations should be unique--don't calleverything `X'!
Observer-assigned temporary designations should be seven characters orless long, and begin in column 6 of the observational record.The designations must not be of the form of the packed (e.g. K23A00B, 00001, ~0023)or unpacked designations (e.g. 2023AB, 1, 620127) used by the MPC.Also:

Observations of NEOCP objects must always be tagged with their NEOCP designations. as well the initial observations made in support of an observatory code request.
Observations reported for the first time when asking for a new observatory code need to include the provisional designation or the number that identifies the object.
Observations of the same object on different nights must be given the same temporary designation only if they are reported in the same message and you are absolutely positive that all the nights refer to the same object. Correspondences of observer-assigned temporary and MPC-assigned provisional designations will be reported back to the observer via e-mail (see also 'How do I understand the designations the MPC sends me?')
Do not continue to use your observer-assigned designations once official provisional or permanent designations have been assigned.

Should I separate my comet and minor-planet observations when submitting them?

The assignment of different types of objects to variousqueues for processing is automatic and based on the orbit correspondingto the designation assignedto each observation. Observations of different types of objects may nowbe freely mixed.

What about batches containing observations from two or more observatory codes?

If you want to submit observations from two or more observatory codes inthe same message, you must group each site's observations under anobservational header appropriate for the site. A representation of anexample follows:

COD 608OBS ...MEA ...... Rest of header ...Observations from code 608COD 644OBS ...MEA ...... Rest of header ...Observations from code 644

Failure to format the message as shown above will result in the batchbeing rejected by the automated routines. Note that later headersdo not inherit anything from earlier headers. So you must include,at a minimum, OBS/MEA/TEL/NET lines on later headers.
Note that this scheme must be followed if there are two (or more) headersfrom the same observatory code in the same message.

Are there any recommendations regarding e-mail?

If you can, please use thecURL submission methodto submit the observations. If you submit ADES observations, the cURL method and website submission forms are also the only methods allowed; you cannot submit ADES by email.

In case you are submitting observations in the MPC1992 format and you want to use the e-mail, the following guidelines should be noted with regard to any e-mail submissionof observations:

Observations must be reported as plain ASCII files. Do not send, e.g., UUENCODE'd or BINHEX'ed files. This is important if you are using e-mail attachements.
Please ensure that your mailer does not split the 80-column observation records--many mailers, such as PINE, will automatically break a line at about 72 characters. In PINE you can avoid this problem if the observations you wish to send are in a separate file by including the file using CTRL-R, rather than by using cut and paste.
If you are using a mailer that can send HTML mail, please disable the inclusion of the HTML version. Inclusion of the HTML version more than doubles the length of the e-mail and the repetition of material is completely useless. In addition, the inclusion of HTML text may trigger the MPC's antispam e-mail filters, causing your message to be flagged as spam.

here

Never send any kind of word-processor/DTP file. If you use a word processor or DTP package to prepare your observations, ensure that you use the package's `Save as ASCII' option.

If you cannot send unencoded attachments and the batches are not more thanfew KB in size, you can use theObservation Submission Form.
Or you can use thecURL submission method to submit batches of any size.

What if I use spam-blocking systems?

If you use any sort of spam-blocking system to sift your incoming e-mail,you are warned that it is your responsibility to ensure that e-mail fromthe MPC is passed unimpeded. The list of e-mail addresses that must beallowed through are autoack/mpc/autodes/des/(initial.surname) atcfa.harvard.edu. If e-mail from any of these addresses is blocked, youmay not get ACKs or designation files. Bounced messages will not be resent.

Note that "Allowed Sender" systems will not work with our automated routinesthat send out information as e-mail returned to certain addresses will bounce.

How do I know that the Minor Planet Center has received my observations?

Upon receipt of a batch of observations, we send an automatic acknowledgement backto you. E-mail is not perfect and messages do sometimes get lost.
If you have not received any acknowledgement from us or if you want to know whathappened to your observations, please use ourWAMO service.

Please also check that you have correctly used all the fields in the header. SeeInformation on how to personalizethe acknowledgement is available.

If something is not clear or you still have questions about your observations, please submit aJira ticket.
Note that the acknowledgement is automatic and simply informs youthat we have received your message. It says nothing about the formattingof the observations contained therein or their quality.

A message to the MPC bounced. Do I need to resend it?

It depends on the source of the bounceback message. obs@cfa.harvard.edu is an e-mailalias (google-group) that forwards incoming messages to various different internal email accounts.
You should only resend your message if the bounceback indicates that obs@cfa is the source of the failure.
You do not need to resend your message if the bounceback comes from any other e-mail address.

What is the purpose of the contact details?

The contact details as published in theMPCsfor each observatory code are intended as a contact point for persons withqueries regarding a specific program. The contact address does not haveto be the street address of the observatory. For professional programs itshould be noted that the contact details are NOT intended to be a list ofP.I.s on the project.
The contact details MUST include:

the name of a person connected with the program (who is willing to answer queries about the presented observations)
a snail-mail address for that person (this can be a P.O. Box)
an e-mail address for that person

Information on how to specifythe contact address (as well as names of observers and measurers)is available.

What are some common mistakes?

Incorrectly-Identified Objects.
If you try to identify objects, ensure that the identifications are correct and that you used the packed forms of the designations in the appropriate columns of the observational records. If in doubt, use temporary designations.
Incorrect Times of Observations
Ensure that the mid-points of your exposures are timed and reported correctly! The most common error by observers (and one of the trickiest to correct if the observation has already been published) is incorrect observation times (or occasionally evendates).
Non-ASCII Submissions.
Ensure that you send only plain ASCII e-mails. Encoded attachments will be ignored by the automated processing routines.
Incorrectly-Specified Observer Details.
If you do not include anobservational header before the observations, the e-mail message will not be recognized as containing observations.
Some observers specify observer details in the form used in theMPCs. These details are usually nicely formatted, but the observation processing routines will ignore them. Observer details must be formatted inthe proper format.

What about coverage on a single night?

You should always supply at least two observations of each object on eachnight. If you are observing objects in dense starfields, you should plan yourobserving session with this recommendation in mind.
If you are stacking images, try and ensure that you produce at least twostacks, remembering that the stacks have to be independent, so an imagecannot be used in more than one stack. If you can produce only one stack,ensure that the observation is marked as a stack ("K" in column 14). Ifyou produce more than one stack, mark the observations as stacked unlessthere is another note you wish to use. If you areobserving at a site that uses codes to distinguish between differentprograms, the "K" should appear on the submitted observation, but will bereplaced by the program code during processing.

What is the difference between reporting two-nighter and single-nighter new objects?

There is no difference between submitting single night or multiple nightsof observation of a "new" object. It is therefore recommended that youreport observations of potential new objects nightly, ensuring that eachobject has a unique designation on each night.

What if I can't follow-up a new discovery?

If you have observed a new NEO, please submit the observations to the MPC(see alsoHow do I report my astrometry?).
If you have observed a new MBO on one night and you are not able to obtain a secondnight within a week or so, you should report the tracklet anyway.
The observations will be subject to the normal checking procedures of theMinor Planet Center (see'Do I need to identify objects?'):

If the object is confirmed as a new NEO, it will go on the NEO Confirmation Page and it may get follow-up for other telescopes.
If the object is not an NEO, but it is identified with a known MBO, then the observations will be published.
If the object is not an NEO and it cannot be identified with any known objects, then the observations are sent to the Isolated Tracklet File (ITF). ITF is regularly checked against new orbits and matches are extracted and published under the assigned designations.

If you wish someone else to follow-up your new discovery, you mayuse theNewObject Ephemeris Generator to generate ephemerides to enable yourcolleague to find the object after the first night.
If someone does follow-up for your new objects, you will get credit for thediscovery even if you have obtained only one night's observations. However,there is nothing preventing your colleague from getting two nights on yournew object and then reporting it to us as a new object. In such a case,credit will be given to your colleague. For this reason, you should notdistribute observations of the new object and you should only send ephemeridesto colleagues that you trust (see also'Who gets credit when single nighters are linked?').

When should I use a discovery asterisk?

Discovery asterisks are placed in column 13 of the observation recordto indicate the discovery observations of an unidentified object. It ispremissable for there to be no discovery asterisk, in which case the MPCwill assume that the chronologically earliest observation is to be treatedas the discovery observation. There must not be more than one discoveryobservation per object (a common error is put a discovery asterisk onevery observation on the discovery night).
Discovery asterisks on submitted observations must only appear onobservations with observer-assigned temporary designations. They mustnever appear on submitted observations with MPC-assigned designations.
There can be more than one discovery asterisks for objects that have not yet been numbered.The MPC will assign the final asterisk when the number and the discovery credits are assigned.See also thisEditorial Note for a more extensive explanation.
The information is published in the monthlyMinor Planet Circulars (MPCs)

I think I have something new. How do I get a provisional designation assigned to it?

New provisional designations are assigned to newly-reported objects thatcannot be identified with a known numbered, multi-opposition unnumbered orrecently-discovered one-opposition (with or without a general orbit) minorplanet.

Note that following the Editorial Note onMPEC2010-U20 the assigmment of a new provisional designation does not mean that you willbe credited with the discovery of the object when it is numbered. The afore-mentionedMPEC should be read to see the new rules regarding discovery credit and thegrandfathering of old multiple-opposition objects. The use of the terms "discoverer" and"discovery" in this document are to be interpreted according to those rules.
New designations are assigned when we have enought observations to compute a reliable orbit.You may use the on-lineNew ObjectEphemeris Generator to generate ephemerides to enable you to find theobject after the first night.

Who gets credit when single nighters are linked?

The credit for the assignment of a new designation is given to the chronologically earliestobservation that is identifiable at the time the designation is to beassigned. If earlier undesignated observations are subsequently located(these will often be isolated observations), the assignment credit does notchange.
Note that this linking process requires the earlier observations be ona different night (at least 12 hours separation) and to beof good quality.

What's the best way to get my discovery numbered?

The first requirement for getting your discovery numbered is to ensure thatthe observations at your discovery opposition cover a sufficient arc to enablerecovery at a subsequent or previous opposition. Note that "your discovery" doesnot imply that this will be the discovery apparition when the object isnumber, if previously-reported observations satisfying the requirements listed inMPEC 2010-U20 are located.
Once identified (or recovered as a result of a direct search), observationsshould be made on pairs on nights in each of two dark runs at eachopposition until the object is numbered. For main-belt objects this canoccur after the object has been observed at four oppositions (although thisdepends on the number and distribution [preferably two nights in each of twodark runs in at least three of the oppositions] of theobservations as well as their quality); NEOs can receive a number after twoor three well-observed oppositions. In addition, objects to be numberedrequire theuncertainty parameter, U, must beless than or equal to two. Note that newly-identified multiple-oppositionobjects are not eligible for numbering: numbering of such objects can onlytake place after the first multiple-opposition orbit has appeared in theMPCs and after further observations have been reported (these canbe at the latest opposition, or at an earlier or subsequent opposition).
The selection of objects for numbering is an automatic process performed justbefore the preparation of each batch ofMPCs. There is no need to ask us "What do I need to doto get such-and-such numbered?". Simply follow the guidelines above andthe object will be numbered when it is ready.

When can I name my discovery?

Asteroid naming is handled by IAU Working Group on Small Body Nomenclature (WGSBN) and not bythe MPC. We encourage users to visit theWGSBN websitefor all matters related to the naming (and associated citation) forall minor planets and comets.
The MPC is not responsible for naming the natural satellites of planets. Naming is handled by the IAUWorking Group Planetary System Nomenclature.

Just for sake of clarity, we report the main information about the asteroid naming process:

Names for minor planets are proposed by the discoverer of a specific object after the object is numbered. Proposals are accompanied by abrief citation explaining the reasons for the naming.
Names and citations proposed by discoverers are judged by the WorkingGroup Small Body Nomenclature(WGSBN) oftheInternational AstronomicalUnion. The WGSBN has publishedtherulesand guidelines relating to the naming of minor planets, as well asthe special naming rules for objects in certain orbital classes. Thedocument also includes information on the procedures used to accept orreject proposals.
Names become official when they appear in theWGSBN Bulletin, published by theWGSBN.
When several provisional designations belong to the same numbered minorplanet, one of these provisional designations is defined as theprincipal designations (this is decided when the object is firstidentified) and it is the discoverer of this principally-designated objectthat is defined as the discoverer of the numbered object.
An alphabetical list of current minor planet names is available. Alist of the discovery circumstances of the numbered minor planets is available.

If you need more information about how to write the citation and submit the name, what names are acceptable, how long it takes for the name to be approved, please contact directlyWGSBN, using their contact email addresscontact@wgsbn-iau.org.

What happens to accepted observations?

Observations are published with different cadences depending on the type of object that has been reported.

Observations of NEOs are published daily in the Daily Orbit Update (DOU, e.g. seeMPEC 2023-Q03). The DOU is available online from the Recent MPECs page.
All the other observations are published in the monthlyMinor Planet Circulars (MPCs) orSupplements.
Minor Planet Electronic Circulars are published for newly discovered NEOs, TNOs and natural satellites.
Observations and orbits of comets and A/ objects are also published (~weekly). (e.g. seeMPEC 2023-P65)

As ofMPEC 2023-D40 (February 21, 2023), Datacite DOIs are available for all new MPECs. The firstpublished DOI is now availablehttps://commons.datacite.org/doi.org/10.48377/mpec/2023-d40.NASA ADS, based here in Cambridge (MA) at the Center for Astrophysics, is in the process of mining therelevant data from Datacite, so that MPECs will be available on their system soon. This will allow all ourusers to cite their observations in scientific articles or proposals. The MPC is also in the process of creating DOIs for all the MPECs that havebeen released before February 21.

What objects go on to the NEOCP?

The objects that go on to theNEO Confirmation Page are those objects which,on the basis of their motion or orbit, appear to be NEOs and that have a digest2 score larger than 65. Objects that are suspected of being comets also appear.
When removed from the NEOCP, the inner-solar-system objects that get put ontoMPECs are as follows:

Any object with perihelion distance less than 1.3 AU
Any object with an perihelion distance beyond 5.5 AU (Centaurs/SDO and TNOs are not listed in only one-opposition)
"Main-belt" objects with eccentricities above 0.5
Comets

In the past, objects with perihelia beyond 1.3 AU and eccentricities between0.4 and 0.5 and/or inclinations above 40 degreesmight appear on anMPEC if there was not much activity.This was deemed to be somewhat arbitrary (particularly in light of the factthat the major surveys were counting how many discoveryMPECs theyhad!).

How do I understand the designations the MPC sends me?

If you have `new' objects you will receive a list matching your temporarydesignations to official provisional or permanent designations. Here isa (ficticious) sample assumed to have been sent in Feb. 1999, showing most ofthe probable forms:

   By0001   (03244   ByLa01    J99A18T   ByLa02   (J81U78A   By0004   (By0003   By0003   (J99A08H

This may be interpreted as follows: By0001 is the numbered object (3244);ByLa01 is a new object 1999 AT₁₈ that is credited to Byers and Langly;ByLa02 is the known unnumbered object 1981 UA₇₈; By0003 and By0004 refer to thesame object, now designated 1999 AH₈, which is a recent discoveryby another team.
In short, provisional and permanent designationsnot prefaced with`(' are your discoveries. Provisional and permanentdesignations will be in thepackedform, as used on the observation record.
New designations are not assigned to objects observed on only one night,although you may receive designations if such objects can be identifiedwith already-known objects.

How quickly are observations processed by the MPC?

In general, observation batches are processed by the MPC as soon as resourcesare available, in the order in which the observation batches were received. Inorder to utilise the resources of the MPC in the most efficient manner,different priorities are attached to the processing of different classes ofobservation. Processing priority is in the following order:

Potential new NEOs/unusual objects and comets, suitable for posting on theNEO Confirmation Page.
Follow-up observations ofNEOCP objects.
Other NEO observations.
Survey observations from last night and recent non-survey material.
Older non-survey material.
Survey observations from before last night.

Observations that are not submitted in the proper format are subject todelay.
Note that the different processing classes are dealt with at different rates.This does not affect the order in which "new" objects are processed.
TheMPC Processing times page reports the current MPC processing status for some of our pipelines with highest priorities.

What (p)recovered objects getMPECs?

In order to qualify for a specialMPEC, (p)recovered NEAs must havebeen observed on two or more nights. When needed, e.g. in the case of virtual impactors,single-night (p)recoveries will simplyappear on the next DOUMPEC (assuming that the observations actuallyfit).
Precovery refers to the identification of images of a single-apparitionobject at an earlier opposition.
TheRecovery Page provides new unpublished observations of NEOs and TNOs that are extending the arc from one opposition to multiple-oppositions and for which additional observations are highly-desiderable. Once new observations provide at least two distinct nights on the second apparition, a recovery MPEC will be issues and the published observations will be removedfrom the page.

Should I check my observations before reporting them to the MPC?

Observer checking does not need to be anything more than checking thatwhat you actually send is what you meant to send. Checking of designations,observation dates and times, positions and theformat is advisable.

I'm interested in photometry.

A goodguide to minor planet photometry is available from Brian Warner.

Movatterモバイル変換

Guide to Minor Body Astrometry

How do I begin?

How do I report observations to the MPC?

How many nights should I report?

What about new discoveries, discovery credits and naming?

MPC processing

Others