Doc Greiner Research Observatory Minor Planet Astrometry Procedure

By Matt Mills

POINTS TO BE COVERED:

• About the Minor Planet Project
• Our Mission Statement
• Main Goals of the Minor Planet Project
• Software Used by the Minor Planet Project
• Choosing Targets for Minor Planet Astrometry
• Filtering Minor Planet Data
• Extended Minor Planet Command in TheSky
• Filtering the MPCORB database file using MPCorb
• Creating Plans for Minor Planet Runs
• Developing a Night’s Plan using the Select_Asteroid_Planner
• Developing a night’s plan using a mosaic plan
• Length of Run and Number of Minor Planets to Image per Plan
• Time Sync with Dimension4
• Minor Planet Astrometry
• Using PinPoint to Find and Measure Minor Planets
• FITS format, WCS World Coordinate System (WCS) and Astrometry
• Catalogue Selection
• Minor Planet Settings in PinPoint
• Plate Solving
• Automatic Detections
• Manual Detections
• Known Object Overlay in Astrometrica
• Find Determination
• Checking your finds with Find_Orb
• Submitting astrometry to the Minor Planet Center
• Interpretation of the reply from the Minor Planet Center
• The best way to follow-up a new discovery
• If you are unable to follow-up a new discovery
• Quick reference guide to submissions to the MPC
• Fast Moving Object (FMO)
• Track & Stack Technique
• NEOCP Uncertainty Maps & Variant Orbits
• Explanation of Uncertainty Map
• Difficulties using Uncertainty Maps
• Big Surveys

About the Minor Planet Project (MPP):

The MPP was begun in 2000 by Greg Sellek and Matt Mills under the guidance of Doc Greiner. The MPP Team used the DocG and DocG2 observatories at the Yanna Research Station of the Madison Astronomical Society to perform minor planet astrometry. During the first four years measurements were submitted to the Minor Planet Center (MPC) by the Team. In 2004, Doc Greiner began discussions with a select group of the observers at YRS to build a private observatory. In 2005, the Greiner Research Observatory (GRO) was built near Middleton, WI. In 2008, The Doc Greiner Research Observatory was built near Evansville, WI.

The mission of the Minor Planet Project is to gather astrometric observations of Small Solar-System Bodies and submit those measurements to the Minor Planet Center. Our goal is to obtain follow up observations, on One-Opposition Unnumbered Objects, so their orbits can be better defined.

Main Goals of the Minor Planet Project:

1. Confirmation and early follow-up of NEOs

It will involve confirmatory observations and follow-up astrometry of newly discovered bright NEOs with a limiting magnitude of mV =18.7.

2. Recoveries of minor planets in the second opposition

Our objective is to improve the orbit of the object. If the Current Ephemeris Uncertainty (CEU) is larger than the RMS of our standard measurements, we can generally improve the orbit. But if your RMS is larger than the CEU, we are definitely not helping the orbit. As a rule, objects with uncertainties < 0.7" never need additional observations. We generally select > 2.0", and filter for second-opposition objects.

3. Follow-up astrometry of newly discovered One-Opposition Unnumbered Objects.
4. Search for new minor planets

Our primary goal is astrometric follow-up of One-Opposition Unnumbered Objects. If observations are planned effectively, there will be also time for searching new minor planets using the mosaic technique. All CCD images are processed not only for target objects, but also blinked for possible new objects.

Software Used by the Minor Planet Project:

• Astronomer’s Control Panel
• TheSky
• MaxIm DL
• Astrometrica
• MPCorb
• FocusMax
• Find_Orb
• Orbitas
• PinPoint
• Select_Asteroid _Planner

The following methods and techniques are used routinely by the Minor Planet Project Team to successfully perform minor planet astrometry and photometry for submission to the Minor Planet Center.

Choosing Targets for Minor Planet Astrometry:

Every minor planet imaging sessions begins with choosing the night’s targets. It should be understood that minor planets can be found everywhere in the sky, but they are highly concentrated along the ecliptic plane. The best choice for new discoveries would be areas of the sky which have not recently been swept for minor planets by the Big Surveys (See: “Notes regarding professional programs”.) Observations within the Doc Greiner Research Observatory’s Minor Planet Project are done on any (at least partly) clear night throughout each lunation.

Selection of targets

We apply two kinds of criteria for selecting minor planet astrometry targets. Observability of particular objects depends on its brightness, motion and position on the sky (especially its solar elongation). Then we deliberate the ephemeris uncertainty depending especially on the length of observing arc in the discovery apparition. A special case is selecting targets for confirmatory observations of newly discovered NEO candidates. They are listed on the NEO Confirmation Page (NEOCP) maintained by the Minor Planet Center. The NEOCP gives very preliminary ephemerides for newly discovered NEO candidates, uncertainty maps are computed and presented on the NEOCP especially for NEO candidates observed for one night only. We check this page nightly just after its updates.

The MPC Orbit (MPCORB) database contains the orbital elements of minor planets that have been published in the Minor Planet Electronic Circulars (MPEC). It gives orbits for all numbered and observable unnumbered minor planets. MPCORB is available for downloading from the anon-ftp link:

http://www.minorplanetcenter.org/iau/MPCORB.html

Filtering Minor Planet Data:

Extended Minor Planets command (Data menu in TheSky)
Use this command to select a Minor Planet data file to plot the positions of all known minor planets on the Virtual Sky. Each time this command is selected, the positions of all minor planets in the selected minor planet file are computed and updated.

To obtain the minor planet file that contains information about the most recent minor planet discovered go to:

http://www.minorplanetcenter.org/iau/Ephemerides/Unusual/Soft06Unusual.txt

to retrieve the list of unusual minor planets and Import into TheSky.

Filtering the MPCORB database file using MPCOrb

Using the MPCOrb program and the MPCORBcr.DAT file you can quickly filter for Minor Planets.

A useful text file is also created called AstPos.txt:

Posiciones para Lat: +43 07 13 Lon: +089 35 59 Alt: 0350 Día 03/10/2006 a las 0 horas TU.

Asteroide A.R. Dec. Mag. "/min

------------ ----------- ------------ ---- -----

2006 NM 20h 27m 38s +36° 28' 58" 16.2 3.4

2006 QL39 01h 11m 44s -01° 27' 41" 16.8 0.5

2006 QW57 00h 03m 43s +13° 56' 39" 17.5 0.6

2006 RZ 20h 46m 53s +34° 56' 54" 14.4 17.3

2006 SS134 00h 49m 21s +16° 17' 47" 16.7 11.4

2005 LC18 03h 06m 18s +17° 39' 38" 17.8 0.3

NEOs can be easily determined.

Creating Plans for Minor Planet Runs:

Developing a night’s plan using the Select_Asteroid_Planner

Obtain Greg Sellek’s visual basic Select_asteroid_planner_ACP2.1vbs for use with ACP in TheSky.

This simple script allows for selecting the number of sets, how long the exposure (in seconds) and how many objects you have to image. A plan is then generated which is used in Astronomer’s Control Panel (ACP). ACP provides an interface for scripting automatic control of telescope mounts and CCD cameras.

First, open TheSky and click on Data, set the Site Information to the run mid-point or use the time skip function to approximate the run mid-point Date and Time.

Populate the minor planets from the mpcorb.dat or Unusual Minor Planets databases to choose your target asteroids.

Next, open the Select_asteroid_planner_ACP2.1vbs program. The script is designed to use the information found in TheSky to create the minor planet run.

You will be asked three questions in the asteroid planner script:

1. How Many Sets? ENTER 4
2. How long Exposure? ENTER 240
3. How Many Objects do you have? ENTER the number of targets you wish to image between 5-12 per run

After the three questions have been answered the remaining fields are entered using data from TheSky by clicking on the object and using the Object Information under the General Tab.

Asteroid Planner Procedure:

Highlight the minor planet name 2006 AR2 and copy it in the field for Object Name #1

Highlight the (only use Epoch 2000 coordinates) and copy it into the field for What are the coordinates for 2006 AR2?

Continue entering the fields until the plan is finished. Here is what the finished visual basic output form Select_asteroid_planner_ACP2.1vbs looks like:

#SETS 3

#INTERVAL 180

1994 RM1 19h 46m 07s -02º 48' 58"

2000 LS34 20h 04m 40s -05º 58' 58"

1999 JO98 20h 10m 23s -07º 14' 36"

2001 UO121 20h 27m 34s -00º 34' 05"

1991 BE 20h 26m 51s +01º 13' 41"

Note: Once the plan has been created it will be found the same folder where the Select_asteroid_planner_ACP2.1vbs is located. The following commands (directives) may be added to your asteroid plan to customize the night’s runs:

#DIR D:\images\2006\MPP\01-01-2006 in the mm-dd-yyyy format

(THIS COMMAND IS MANDATORY) Indicate the location of the file which you created on the drive D:\images\ for your nights run. By convention we name the file for the night/morning run MM-DD-YYYY.

#waituntil 1, 25-Nov-2005 06:00:30 ; UTC

If the run does not need to begin until a specific time add this line. Be sure to use UT.

#CHAIN D:\plans\11-24-2005planB.txt

Runs may be linked together so imaging can be performed over the entire night. Be sure to use different plan names for each run.

#AUTOFOCUS

Use the auto focus command line to add a FocusMax routine at the beginning of your run.

#afinterval 30

Use this command line to add a FocusMax routine at a specific time interval, 30 minutes in this instance.

Here is an example of a typical DGRO run, note the ‘chain’ to a second run at the end of the plan:

#DIR D:\images\2007\MPP\05-19-2007 ;begin 1:20 AM

#SETS 3

#INTERVAL 180

#AUTOFOCUS

1994 PX 15h 26m 35s +01º 14' 31"

1998 RE2 15h 27m 03s -03º 21' 47"

1999 YF5 15h 34m 20s -02º 18' 37"

2002 CN108 15h 42m 02s -04º 42' 45"

1998 FY11 15h 55m 03s -05º 16' 41"

2002 FF22 16h 09m 29s -07º 13' 26"

1997 CR 16h 14m 27s -00º 22' 05"

#CHAIN D:\plans\2007FK1plan.txt

Developing a night’s plan using a mosaic plan

While there are many times when you may want to specifically select certain objects for observation, there are other times when you may just want to 'cast the net' and see what you find. Use TheSky’s Mosaic Tool to cover an imaging area.

Then use the, Sky6MosaicToPlan.vbs, script to generate a mosaic plan from the Mosaic Tool’s advance “Copy to Clipboard” function.

#DIR D:\images\2008\MPP\2-24-2008

#SETS 3

#INTERVAL 180

#AUTOFOCUS

STACKALIGN 3

Mosaic_0 10.57802392 18.73864312

STACKALIGN 3

Mosaic_1 10.60154277 18.73960883

STACKALIGN 3

Mosaic_2 10.625061 18.73993072

STACKALIGN 3

Mosaic_3 10.64857923 18.73960883

STACKALIGN 3

Mosaic_4 10.67209808 18.73864312

STACKALIGN 3

Mosaic_5 10.57811598 18.40456931

STACKALIGN 3

Mosaic_6 10.6015888 18.40553309

STACKALIGN 3

Mosaic_7 10.625061 18.40585435

STACKALIGN 3

Mosaic_8 10.6485332 18.40553309

STACKALIGN 3

Mosaic_9 10.67200602 18.40456931

STACKALIGN 3

Mosaic_10 10.57820609 18.07050108

STACKALIGN 3

Mosaic_11 10.60163386 18.07146301

STACKALIGN 3

Mosaic_12 10.625061 18.07178365

So the images are stacked and aligned in MaxIM and ACP.

Length of run and number of asteroids to image per plan

Our minimum number of asteroid targets in a run is 6. Three images per set is the minimum, four is better. The exposure duration can be 180 seconds to reach magnitude 18.7 on an average Wisconsin moonless night.

[Run Time for 6 objects x 180 second exposure + 1 focus and syncing = 1.5 hours]

The maximum number of targets per run before a second run would need to be ‘chained’ is 12. Be sure not to begin such a long run past the meridian in the West or the targets will surely set before the run has completed.

Time Sync

This may be one of the most IMPORTANT steps in performing astrometry. Since the object’s location is constantly moving, time is an equally important an element as location is for measurement. So syncing the computer’s clock to Atomic Time is essential in providing sub-arcsecond determinations for the MPC.

Dimension4 software is used to time sync the DGRO computer prior to beginning a night’s session.

Routine procedure:

· In ACP choose Browse and select AcquireImages.vbs

· Next choose Main and select the plan you have created and save in D:\images\2007\MPP\

· Once the plan is opened the run will begin slewing to the first object’s position and continue till all images have been acquired.

Minor Planet Astrometry

The Minor Planet Project uses many different programs in its minor planet search routine. TheSky, ACP, MaxIM and FocusMax software are used to point the telescope, take images and focus the optics. PinPoint is used to measure the minor planets position and perform plate solving. MPCOrb is used to filter the MPCORB.dat database. Astrometrica is used to overlay known objects in an image. Orbitas is used to determine the best window of time for peak magnitude and opposition. Find_Orb is the orbital software which gives us the residual used to determine if our astrometry is acceptable.

Using PinPoint to find and measure minor planets

PinPoint is an astrometric tool than can identify star fields. This can be used to adjust telescope pointing and re-sync a telescope mount with the sky. PinPoint uses the ASCOM Platform. PinPoint is an image analysis program which pattern matches reference stars, plate solves the image, and saves WCS World Coordinate System (WCS) information to the FITS header. PinPoint also analyzes sets of three images and finds moving objects, providing astrometric and photometric information on each, and formatting a report for submission to the MPC.

FITS format, WCS World Coordinate System (WCS) and Astrometry

Astrometry is the precise measurement of the position of celestial objects, such as stars, minor planets (asteroids), supernovae, and comets. In the case of new discoveries, this can be extremely important for orbit determination and for planning follow-up observations. Each image you take and save to a FITS format has additional information imbedded in the image too. The most important information for astrometry is the WCS information.

Once PinPoint is set up for the star catalog and the general characteristics of your images, the analysis is fully automatic. The program finds all the stars in the image, matches against catalog positions for stars in that vicinity, and then calculates a mapping between the catalog and the image. This mapping is stored as WCS values in the FITS Header of the image. The WCS header information is standardized, so it is compatible with many other software applications.

Note, since this PinPoint version utilized in MaxIM is using the GSC (a limited catalog) a second plate solve is required with a larger and more accurate catalog to submit to measurements to the MPC.

Catalogue Selection

The most important factor in success of plate solving is the selection of the reference catalog. PinPoint requires a certain number of stars to match, depending on the number of image and catalog stars available. The absolute minimum is 6 stars. As the number of stars detected in the image increases, and/or the number of catalogue stars in the field increases, that minimum number is dynamically adjusted upward to 50. If there are many catalog stars in the area, yet few image stars, the chances of a false match are increased. Thus, you need to expose down to the faintest stars in the catalog, usually a 30 second exposure will do.

Catalogs

The USNO-B catalog is the successor of the USNO-A2.0 and presents positions, proper motions and magnitudes for more than a billion objects. Due to the enormous size (80 Gigabytes), this catalog is not distributed by the USNO, but it is available online through the Internet.

The full USNO-A2.0 catalog contains entries for more than 526 million stars.

The Tycho 2 catalog contains 2.5 million entries over the whole sky.

The ACT Reference Catalog contains entries for 988758 stars over the entire sky.

The UCAC 2 (second U.S.N.O. CCD Astrograph Catalog) contains positions and proper motions for 48 million stars down to R = 16, covering the sky from the south celestial pole to mid-northern declinations.

The Guide Star Catalog 1.1 (GSC) is the most commonly used catalog, and is suitable for most images. It contains stars down to about 17th magnitude, so any fainter stars in the image cannot be used for matching and solution. The GSC is used in our MaxIM/PinPoint LE version to speed up the search process since it is a much smaller catalog.

It is the recommendation of the Minor Planet Center that observers not submit measurements using the GSC as their reference catalog. Instead observers should submit using astrometry from the UCAC 2 catalog or USNO-B catalog.

Use these minor planet settings in PinPoint

Plate Solving

Plate solving is the process matching stars in the image to known stars in a reference catalog and writing transformation info to the FITS Header. This transformation info the World Coordinate System (WCS) data allows a FITS image to be used for direct astrometric measurements since the image scale, projection geometry, and center-point coordinates are accurately known. This also allows use of the image for astrometric purposes at later times without re-matching to a catalog and re-solving the plate.

Find Asteroids

PinPoint can handle multiple sets of two or more images for blinking. If you have three or more images in a set, you can also use PinPoint's automatic detection capability. If you use more than three images in a set, the minor planet must be detected on all plates. While using four images in a set will reduce false detections.

Use these solve settings in PinPoint

Find Asteroid Sequence

1. In the Find Asteroids tab of Visual PinPoint, use the Add Files button or drag-and-drop to put a few sets of your images into the list window. They will automatically organize themselves into sets in a tree display. You can also use the Get Solved button to automatically transfer any images listed in the Solve Plates list into the Find Asteroids list.
2. Select Blink All Image Sets.
3. Click Find Asteroids. All sets containing three or more images will be scanned for minor planets, and those that are found automatically will be entered into a database.
4. After a while a blink display will appear. If there are automatically detected asteroids, they will be indicated by crosshairs. The yellow/green marked one is the one you are verifying. If you think it's real, click Accept, otherwise click Reject.
5. Eventually the blink display will switch to manual mode. You can tell this by the appearance of the Report button in place of the Accept button. You will see all of the automatic detections and previously reported manual detections marked by blue cross hairs.
6. If you see an unmarked asteroid, click anywhere once to stop the blinking. Use the mouse or F6-F7 keys to step between the frames and mark the asteroid. Click Report to add it to the MPC report (Find.txt).
7. Repeat for each manual detection. When you have reported everything you found manually, click the “Done” button.
8. The report contains astrometry on the moving object detections and the MPC report header lines.

Automatic Detections in PinPoint (DO NOT RELY ON AUTOMATIC DETECTION TO FIND ALL MINOR PLANETS PRESENT IN YOUR IMAGES. EXAMINE EACH SET MANUALLY FOR MINOR PLANETS THAT WERE MISSED BY AUTOMATED DETECTION)

If any objects were detected automatically, the blink window first appears with the three buttons shown on the image to the right and the first automatically detected object is marked in each frame by yellow reticules. The other (as yet un-reviewed) automatic detections are marked with blue reticules.

To accept a detection (and have it included in the MPC report), click Accept.

To reject a detection and go on to the next (e.g., it is a false detection), click Reject. If you want to skip all remaining automatic detections and proceed to manual marking, click Manual.

Once all automatic detections have been reviewed and either accepted or rejected, or if the Manual button is clicked, the blink window switches to the manual detection mode (see the next section). If you want to stop blinking completely, click the [X] box in the upper right corner of the blink window.

Manual Detections in PinPoint

Once in manual mode, the three buttons change to those shown in the image to the right. Click on the object to be marked on a frame and a yellow reticule will appear at its astrometric position. If the reticule appears on a nearby object, the one you tried to mark was not detected by PinPoint. Adjust your detection sensitivity settings to go deeper (at the possible cost of more false detections).

Mark an object on at least one frame (usually on all frames). Then click Report to add the marked/reported positions for this object to the MPC report. Once you report a manual detection, the window will again start blinking and the just-reported positions will appear with blue reticules (so you can avoid re-reporting them). Repeat this cycle for each object that you want to report manually.

When you have finished marking and reporting objects manually, click Done. The MPC report will appear in Notepad as your Find.txt.

Known Object Overlay

Not all Minor Planets can be easily seen in the blinked images in PinPoint. Astrometrica has a command which will mark the nominal position of all known minor planets and comets on the currently loaded CCD images. Besides the packed designation of these objects, the predicted magnitude is also displayed. Note that the nominal position is calculated from the orbital elements in the MPCOrb database, without taking account for planetary perurbations, so this command is useful for identifying of locating a minor planet on the frames, but should not be used to judge the quality of a measurement. The Known Object Overlay command can also be enabled with the blinking feature on.

The following settings are used in Astrometrica:

Find Determination:

Checking your finds with Find Orb

Click here to download the 32-bit version of Find Orb the ‘Find’ checking and orbit determination software. This program is a useful tool in determining your measurement residuals. When you attempt to determine an orbit for an object, you will always find some difference between the "observed" positions (measured from a CCD image), and the "computed" positions (computed using the orbit you have determined). These differences are known variously as "residual errors", or "residuals". The measurement is in "RMS" = "Root mean square"; it's a modified version of the average of the residuals. It is the square root of the average value of the square of the residuals. If you took the squares of all the residuals, averaged them, and took the square root of the result, you would have the RMS error.

Your Find.txt from the night’s asteroid run is checked for residual error in the Find Orb program. Be sure to save your Finds in a separate file and name it.

Open Find Orb to check the residual error in your finds.

Click Open in Find Orb. Highlight the Find.txt file and click Open.

Now click on each designation and make sure the RMS error is < 0.7 to accept (our criteria of submission to the MPC). Delete those designations which have RMS error > 0.7 from your find text before submission unless the CEU can be improved upon. Most of the residual error we find will be <0.2. If the residual error is between 0.7 and 0.5 use the Minor Planet Checker to verify the find, as below. If the MPChecker indicates,” No known minor planets” or offset different from ‘0.0E’ RA and ‘0.0S’ DEC, you may have discovered a new minor planet.

The "Further observations?" column will contain a range of dates when additional astrometry would be useful. If all the objects show today's date in the "Further observations?" column, it means that the area hasn't been scanned yet by the Big Surveys. Note that if the minor planets were observed on more than one night over an interval of less than 10 days, then any potential discoveries have probably already been linked. You can confirm this by checking the "Orbit" column in the MPChecker output. Any object showing a “V” is classified as a Vaisala computation, which means it has been observed already on two nights during the present opposition.

Submitting astrometry to the Minor Planet Center (MPC)

The detection capability in PinPoint produces the format for reporting astrometic observations automatically, the Find.txt. Be sure to use the PinPoint derived provisional (Temporary) designation when submitting to the MPC. PinPoint assigns each astrometric observation its own provisional designation. Observations that are not submitted in the proper format are subject to delay or rejection of your submission by the MPC.

Note: Check your measurements in Find_Orb prior to submission to the MPC, see ‘Checking your finds with Find_Orb’ above.

Observations of both minor planets and comets are reported via e-mail to mpc@cfa.harvard.edu. Copy and paste your find data into the body of the e-mail. Email the submission in Plain ASCII Text format.

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.

Always report the position for every moving object in your image. Do not assume that just because an object is numbered that continuing observations are not important. The inclusion of named and numbered objects, particularly when there are also observations of unidentified objects, serves as a useful check of the quality of the measurements.

If you have set up PinPoint correctly the observer details will be included in your submission:

COD XXX

CON Matt Mills, Minor Planet Project Greiner Research ObservatoryI

CON [XXX@XXX.net]

OBS M. Mills

MEA M. Mills

TEL 0.4-m f/8 Ritchey-Chretien + CCD

NET UCAC2

ACK Submission by Matt Mills

T00162 C2005 12 02.36429 09 35 27.18 +29 32 29.7 18.8 R xxx

T00162 C2005 12 02.40391 09 35 28.95 +29 32 27.3 19.1 R xxx

T00162 C2005 12 02.44358 09 35 30.07 +29 32 19.5 19.3 R xxx

Interpretation of the reply from the Minor Planet Center

Upon receipt of a batch of observations, MPC sends an automatic acknowledgement ‘ACK’ back to you. If you do not receive the acknowledgement within 24 hours you should resend the original message, noting in the subject line that the message is a retransmission (ensuring your subject line contains `RESEND' is a good way). Information on how to personalize the acknowledgement is available.

The acknowledgement ‘ACK’ contains a 'junk' rating for the message that was submitted. The junk rating is the percentage of the submitted message that was not useful (i.e., material that was not observational records, observational header or e-mail header). Note also that the acknowledgement is automatic and simply informs you that we have received your message. It says nothing about the formatting of the observations contained therein or their quality.

New provisional designations are assigned to newly-reported objects that cannot be identified with a known numbered, multi-opposition unnumbered or recently-discovered one-opposition minor planet. The provisional and permanent designations not prefaced with `(' are your discoveries. Provisional and permanent designations will be in the packed form, as used on the observation record.

New designations are assigned upon the receipt of observations from two nights. The two nights should be fairly close together, certainly within a week of each other. You may use the on-line New Object Ephemeris Generator to generate ephemerides to enable you to find the object after the first night. This tool uses the Vaisala calculation to generate an ephemeris. Objects traveling less than 2.5”/minute have been successfully found by the DGRO using the New Object Ephemeris Generator.

If the new object (observed on two or more nights) can be matched to an earlier undesignated one-night stand, that 1-night stand does not have priority and you will receive the credit for the discovery. If your new object can be matched to an earlier designated 1-night stand (generally this will be a re-designation from a published 2-night object), your new object will also have priority.

If you report "New"(in the subject line) objects as two nights of observation in a single message, those observations are passed straight to the designating routines once it has been determined that they do not belong to some already-known object. Your submission should include an ‘*’ after your temporary designation to indicate which observations you wish to claim as a “new” discovery. Your submission should look like this:

COD xxx

CON Matt Mills, Minor Planet Project

CON [XXX@XXX.net]

OBS M. Mills

MEA M. Mills

TEL 0.4-m f/8 Ritchey-Chretien + CCD

NET UCAC2

ACK Submission by Matt Mills

T00066* C2007 04 17.16050 13 36 48.01 +11 28 57.3 18.8 R xxx

T00066* C2007 04 17.18488 13 36 46.66 +11 28 55.9 19.0 R xxx

T00066* C2007 04 17.20917 13 36 45.35 +11 28 55.5 18.6 R xxx

T00066* C2007 04 21.09808 13 33 18.48 +11 24 32.4 17.7 V xxx

T00066* C2007 04 21.12249 13 33 17.25 +11 24 30.9 18.3 V xxx

T00066* C2007 04 21.14694 13 33 15.93 +11 24 28.4 18.5 V xxx

If you report a "New" object as a 1-nighter, once it is has been determined that they do not belong to some already-known object, the observations are passed to routines that try to link the observations to other recent 1-nighter objects. Only if a link is found do the observations get passed to the designating routines (although they first again go through the checking routines).

Note that if the automatic processing routines ‘APRs’ determine that the two nights attributed by an observer to a presumed single object do not in fact appear to belong to the same object, the observations of that object will be returned to the observer and will not get processed further. This splitting of nights may occur if the APR determined that the two nights do not belong to the same object or if the observations are of such low-quality that the validity of the night-to-night linkage cannot be guaranteed.

If one of your 1-nighter is linked to someone else's 1-nighter, the credit for the discovery is given to the chronologically earliest observation. If earlier undesignated observations are subsequently located (these will often be isolated observations), the discovery credit does not change.

Note that this linking process requires the earlier observations to be of good quality (the automated routines currently reject linkages where one or more observations appear to be off by RMS 1.5” or more).

If it turns out that an NEOCP object is identical to an object that has already received a provisional designation that has been published in the MPCs and the MPSs (i.e., the permanent publications), the observations that have already been published are not republished on the MPEC announcing the object (i.e., a temporary publication). Such cases are indicated by the lack of a discovery asterisk amongst the listed observations and the use of 'Additional observations' as a heading, rather than 'Observations'.

New designations are not assigned to objects observed on only one night, although you may receive designations if such objects can be identified with already-known objects. Observers with at least one discovery credit may request the (roughly) monthly receipt of a DISCSTATUS report, which lists their discoveries, as well the current disposition of each object. Requests to be added to the mailing list for DISCSTATUS reports should be made to the normal submission address (subject line should be "DISCSTATUS" and the message should indicate to which e-mail address the report is to be mailed).

The time delay between your submission of "New" objects and your receipt of the designations corresponding or newly-assigned to your objects is variable. If things are relatively quiet at the MPC, you may receive designations back within a matter of minutes. In other cases, it may be more than 24 hours or more before you receive anything.

Note that objects that are placed on the NEO Confirmation Page will not be assigned designations until they are removed from the page. Objects will remain on this page until there is sufficient material to allow the preparation of an MPEC. If an object remains unconfirmed, it will normally be removed (and noted as being lost) five days after the initial posting. When a removed object is flagged as `does not exist', it means that the object was retracted by the observer. If flagged as `lost', it means that either the object exists but was not confirmed, or that it does not exist. Presumably some sizeable fractions of the objects flagged as `lost’ are really 'does not exist' cases.

The best way to follow-up a new discovery

After the initial two nights, wait for a week or ten days, then obtain another pair of nights a day or two apart. Ephemerides can be generated using the Minor Planet Ephemeris Service. There really is no point in following a new object night after night. Further observations can then be made between fifteen and twenty days after discovery (if the Moon permits). You should always supply at least three measurements of each object on each night. Otherwise, take the list of minor planet and put it into MPES. Check the "Show residuals blocks" to determine when the minor planets were last observed. If it was less than ten days ago, chances are that the MPC will link your 1-night discovery with any 1-nighters from the earlier date. You will need at least a two-night discovery to take priority over any earlier 1-nighters.

If you are unable to follow-up a new discovery

If you observe an object on one night and are not able to obtain a second night within a week or so, you should report these "1-Night Stands".

The observations will be subject to the normal checking procedures of the Minor Planet Center but will be published only if they can be identified with some already-designated object. They are then checked against recent 1-night stands. If a match is found then the object can receive a designation. The discovery will be credited to the earlier observation: if earlier undesignated observations are then identified, the discovery credit does not change. If no match is forthcoming, the 1-night stand observations are filed. These files are checked regularly against new orbits and matches are extracted and published under the already-assigned designation.

If you wish someone else on the MPP team to follow-up your new discovery, you should use the New Object Ephemeris Generator to generate ephemerides to enable them to find the object after the first night.

If someone does follow-up for your new object, you will get credit for the discovery even if you have obtained only one night's observations. However, there is nothing preventing them from getting two nights on your new object and then reporting it to us as a new object. In such a case, credit will be given to your team member. In reality, if you find a new object on one night and submit it, all you've done is follow-up a discovery for LINEAR. If you want to keep your 1-night discovery, don't submit it right away. Wait and get a second night. Submit both at the same time and with a bit of luck, you'll get the discovery credit and LINEAR provides a bonus third night. In the case when you are imaging prior to moonrise, it's a good idea to send in a 1-nighter. The Big Surveys will be passing through in days and they will provide the second-night confirmation.

If there is no one in the team able to follow-up on the 1-nighter due to weather or time constraints the new object can be posted to the NEO Confirmation Page NEOCP. You need to put "NEO candidate" (or something similar containing "NEO") in the subject line. If you do that and it can't be identified, it gets moved to a queue for inspection for possible NEOCP posting. If you don't include "NEO" in the subject line, it'll get dumped in the MBA queue.

Quick reference guide for submissions to the MPC

New Discovery	"New" in the subject line	Use the same temporary designation for both nights followed by an ‘*’
NEOCP “1-Night Stand”	"NEOCP" in the subject line or "NEO" in the subject line	Create a temporary designation using ###### to make a combination of 7 digits or letters followed by an ‘*’. This will allow for a quick reference to our submissions on the NEOCP page.
NEOCP Follow-up	"NEOCP Confirmation" in the subject line	Use the NEOCP designation
New Comet	"COMET" in the subject line	Use out same temporary designation for both nights followed by an ‘*’
Routine	“Submission (Observatory Code)” in the subject line	Use our temporary designation

Fast Moving Object (FMO)

Acquiring images of Near Earth Objects (NEOs) is complicated by the fact that the target moves rapidly relative to our position on the Earth. This means that the coordinates change with time and thus, to center the target in the image frame, the coordinates must be calculated for the time of the exposure. By using orbital elements, you provide ACP with the formula for calculating the position of the target at the time you actually start the exposure. ACP accepts minor planet orbital elements in the Minor Planet Center "1-line" format. A typical NEO rate of motion might be 2 arc seconds per minute giving an optimal exposure of 2 minutes. However many objects travel faster than this and in some cases the optimal exposure is just 15 seconds. Currently, our system’s limits are 15 second exposures unbinned for a magnitude 18.7 NEO traveling at 30”/minute. The following commands (directives) are used in conjunction with the MPC 1-line format to center the object in the image:

#TRACKON

Initiates orbital tracking of small solar system bodies. This remains in effect until cancelled by #TRACKOFF. Orbital tracking will not be done except for solar system bodies, so non-solar-system targets may be intermixed without harm. Autoguiding will not be done if orbital tracking is active. Note that orbital tracking requires orbital elements as the target specification (major planet targets will also be tracked). For example: #TRACKON

#TRACKOFF

Cancels orbital tracking. This remains in effect until re-enabled with #TRACKON. For example: #TRACKOFF

These commands (directives) control ACP's orbital tracking feature, where the motion of the minor planet is fed into the telescope and its tracking is adjusted to match the motion. An orbitally tracked image will show trailed stars and a stationary minor planet.

Track and Stack Technique

This technique is called Track and Stack. The 'Track' part of Track and Stack technique relies on knowing the motion of the object (i.e. the speed and direction it is moving in) reasonably precisely, even when the actual position of the object may not be that well known. This is almost always the case, even with newly discovered objects with only preliminary orbits calculated from just a few precise astrometric positions, the general speed most commonly, “/min is used and the position angle (P.A.) direction of travel is often well determined even when the predicted RA & DEC coordinates may have large uncertainties.

Track and Stack allows many individual images of a moving object to be aligned so that each image is offset from the last by the precise motion of the moving object (Speed and P.A.), this makes the background stars appear to trail and keeps the object as a point source. The more images that are stacked together the fainter the target object that can be imaged. For Fast Moving Objects (FMO), often the object is not visible at all on individual frames and is only revealed when many images are stacked together.

Here is a sample ACP plan:

#DIR D:\images\2007\MPP\06-19-2007

#INTERVAL 20

#BINNED 2

#SETS 10

#STACK 5

#TRACKON

K07M00Q 23.7 0.15 K074A 329.73819 238.60272 112.60110 1.67459 0.7396642 0.25687616 2.4508695 7 E2007-M15 31 1 1 days 0.42 M-v 3Eh MPC 0000 2007 MQ

#TRACKOFF

Plates solve all images prior to stacking.

For best results star trails should be kept to a minimum. In order to calculate the minimum exposure time for the speed of an object use this calculator based on the following equation:

(Arcseconds/pixel) * 2 / (speed of object in Seconds) = Total Exposure Time in Seconds

NEO Exposure Time Calculator

Use the “Stack” image to locate the object but measure from each individual image for submission. Take multiple exposures and stack them at a typical asteroid velocity (speed and P.A.). The stacking will build up signal and reduce random noise.

NEO Plan Generator and the NEOCP Orbit Plan Generator

These programs are a web based tools designed by John Mills to quickly generating plans utilized by the AcquireImages.vsb script in ACP. They can be accessed from the home page of the Minor Planet Project.

NEO Plan Generator

The NEO Plan Generator is a dynamic webpage created by John Mills to quickly make NEO plans using the Minor Planet Center’s 1-line elements format. The text file plans generated in the webpage utilize default setting for the directives used by the ACP AcquireImages.vsb script. Here is a sample ACP plan:

#DIR D:\images\2007\MPP\06-03-2007
#INTERVAL 120
#SETS 10
#TRACKON
K07K07H 16.2 0.15 K074A 338.78292 350.65092 299.07499 22.42821 0.5067767 0.21632437 2.7483102 8 E2007-K67 12 1 2 days 0.22 M-v 38h MPC 0000 2007 KH7
#TRACKOFF
#CHAIN D:\plans\

NEOCP Uncertainty Maps & Variant Orbits

Explanation of Uncertainty Map

The above plot gives an indication of the expected sky-plane uncertainty of the specified object at the specified date and time. The uncertainty is shown as offsets (in seconds of arc) in both RA and DEC from a nominal prediction. The NEOCP prediction is the nominal prediction and, by definition, has offsets of zero in both RA and DEC.

Use the first line to begin the search on the “orbits” page; it has the word “nominal” at the end as the 1-line element in your plan. Most new objects will be found near nominal in follow up observation of NEOCP objects. Choose the “orbits” link and copy the 1-line element to your NEOCP plan. Be sure to check the “observations” link to see other observations and read the submitted comments too.

The locations of the object according to other predicted variant orbits computed from the initial observations are shown by the colored triangles at the appropriate offsets. If a lot of these predictions cover only a small amount of sky, you may see a solid area of color, rather than the individual triangles.

With this map you can try finding the object, often by starting at the most likely place where the RA and DEC offsets are both zero (the nominal position) and then working outwards until the object is found.

The ephemeris provided directly from the NEO Confirmation Page are calculated for the nominal position only and the rate of motion at the extremities of the uncertainty map can be significantly different (faster or slower motion) and can make the detection very difficult or even impossible if the object is far from the nominal position.

The uncertainty maps include an indication of objects that are close to the earth. Three colors are used to indicate objects at various distances:

o green, for objects that are more then 0.05 AU from the earth at the time used for the uncertainty map;

o orange (supposedly) for objects between 0.05 and 0.01 AU from the earth

o red, for objects within 0.01 AU.

On the list of offset coordinates, variant ephemeris positions that are orange on the map are flagged by "!" and positions that are red on the map are flagged by "!!".
In addition, the NEOCP now flags those variant orbits that will be coming within 0.0027 AU (roughly one lunar distance) sometime in the next 100 hours. Such objects will be shown in black on the uncertainty maps and flagged with "***" on the lists of offset coordinates.

Difficulties using Uncertainty Maps

An observer searching for an object using an uncertainty map faces a number of issues:

• The area to be searched may be much larger than a single field of view of the CCD camera, careful planning of the search area may be needed.
• The object may be moving fast, making it difficult to ensure accurate coverage of the whole area. Offsetting from the nominal position can be prone to mistakes, especially as the distance away from the nominal position increases.
• The uncertainty area expands with time, sometimes appreciably in just a few hours 
• The difference in apparent speed from one side of the uncertainty area to the other may be significant; ideally the imager needs to take this into account when stacking if searching for faint fast moving objects.
• Most NEOCP objects are relatively slow moving and often close to their predicted positions while others are fast moving with correspondingly larger uncertainties. Generally, only those with uncertainties larger than your field of view require observation.

Note: A position at coordinates 0,0 on the map is regarded as the most likely place to find the object (the nominal position), but there is a possibility that the object could be found anywhere on the map. Sometimes objects with unusual motion or with uncharacteristically poor discovery positions lie completely outside the uncertainty map.

Big Surveys

The big professional surveys such as LINEAR, LONEOS, NEAT, Spacewatch, CSS, and others sweep large areas of the sky and are very successful at discovering minor planets. LINEAR takes FIVE (5) images of each field, total spacing about 1 hour. Linear is capable of taking 7,000 images in a night. CSS, E12, and LONEOS all take FOUR (4) images of each field, with intervals varying from 20-60 minutes from first to last image. SPACEWATCH and NEAT take only 3 images, spaced by 20-60 minutes, but they both have SMALL (~1 arcsecond) PIXELS. Each and every of the aforementioned professional survey programs submits all objects as new objects. Meaning, each object observed on a given night has its own, observer-assigned unique temporary designation. These observations pass through their automatic processing code. The remaining 1-night objects that might be NEOs are left for further examination and are posted on the NEOCP.

Click here to see a time-lapse daily Sky Coverage Map.

Click here to get a map showing current MPC observatory locations in the US and Canada.

Note: The Big Surveys are mainly concerned with NEOs and FMOs. They typically do not return to the surveyed area for a second-night observation. It is possible for the amateur to provide two linked nights of astrometry on one of their ONS and receive credit for the discovery.