Target Asteroids!


Prerequisites for participation.

  • An interest in astronomy.
  • An interest in observing and providing data to the scientific community.
  • An interest in learning more about asteroids and near-Earth objects.
  • Appropriate observing equipment or access to equipment.

Register on the website

  • Complete the Target Asteroids! Registration Form.
  • Press the submit button to register your interest in the project.
  • Within one week of registering, you will receive confirmation of your registration.
  • After confirmation you will have access to communication with other observers via the Target Asteroids! email list.
  • Periodically you will receive updated information about the program.

Obtain instrumentation.

The minimum instrumentation recommended to participate in this project is:

  • Telescope 8” or larger;
  • CCD Camera, Computer with internet connection; and
  • astrometry software.

If you have an appropriate telescope and CCD camera, you will be able to observe asteroids on the Target Asteroids! list. The asteroids that can be observed depend on the telescope’s aperture (diameter of the mirror or lens), light pollution, and geographic location.

If you do not have a telescope, you can still participate in the program by obtaining access to observing equipment:

  • You may team up and use a telescope owned by a friend, astronomy club, local college or planetarium observatory.
  • Several private telescope services from which you may purchase telescope time provide good observing locations all over the world. Examples are Sierra Stars Observatory Network, or LightBuckets. (Note: The Target Asteroids! program does not endorse any specific vendor).
  • There are organizations that partner with large private and public observatories, which provide images for schools and students. They measure the computer images for astrometry (position with respect to back ground stars) and submit the data to designated organizations such as OSIRIS-REx’s Target Asteroids!, Astronomical League, Association of Lunar & Planetary Observers, Collaborative Asteroid Light curve Link, and the Minor Planet Center. Registrants using this option will need to make their own connections and arrangements for these submittals.
  • Local astronomy clubs provide connections and opportunities for observations. Are you a member of a local astronomy club? If not, we recommend it! You will meet friendly members who will be happy to help you. Check out our partners, NASA Night Sky Network and The Astronomical League, to locate a club near you.

Review the Target Asteroids! list on the website for objects for which we need data.

Check the list for new additions. The program will update the list as needed but at least annually. When updates occur, we will send out a notification to the Target Asteroids! listserv (members include those participating in the Astronomical League’s Target NEOs!).


Plan your observing session(s) for a particular object or objects accessible from your location with your telescope.

Because not all asteroids are visible at the same time or in the same part of the sky, observers determine their own observing schedules. Many sky calendar software programs download the latest asteroid ephemerides (astronomical positions) from the IAU Minor Planet Center (MPC). These allow the observer to plan each evening’s observing session.


Observe an asteroid and collect data.

An observation consists of at least 3 digital or photographic images of the asteroid (centered) acquired over a ½ hour or more and corresponding electronic files processed for one or more of the following:

  • astrometry (precise, accurate positions against a star field);
  • photometry to 0.1 magnitude accuracy; V or R is best; and
  • spectroscopy while difficult for these faint objects is welcome.

(Contact Carl Hergenrother if you would like instructions on how to produce these observations, including the use of digital SLR cameras).

The ideal observation documentation consists of three images corrected for flat field and dark subtraction, along with corresponding astrometry in standard IAU Minor Planet Center format (used by the most popular astrometry programs). Refer to the excellent NASA Amateur Observing Program here: and Brian Warner’s Guide to Photometry:

Make sure:

  • You are observing the correct asteroid and that it is a real object (not an image defect);
  • There are 12 or more reference stars in the field of view for astrometry and/or photometry;
  • You use the proper order fit correction; and
  • You place the asteroid of interest near the center of the field.

There are many excellent software packages available that allow the observer to locate asteroids, capture images, and “track-and-stack” many images to capture faint asteroids.

Collect the following information:

Basic information
  • Date (universal time or local time)
  • Time (accurate to the nearest second; universal time or local time)
  • Target Asteroids! object observed
  • Latitude of observer or telescope, if remote (nearest 10th of a second)
  • Longitude of observer or telescope, if remote (nearest 10th of a second)
Observer Information
  • Name
  • Email
  • Minor Planet Center Code (if any)
  • Names of additional observers or measurers
  • Submitter’s contact information if different from observer
Special requirements for each observation
  • CCD flat field
  • Dark or bias subtraction
  • Accurate computer time +/- second
  • Type of telescope (reflector, Schmidt-Cassegrain, etc.)
  • Aperture
  • Type or brand/model of CCD
  • Filters used (V or R?)
  • For photometric observations, standard star catalogue used
  • Minor Planet Center (MPC) code for the observer (if the observer has one)
  • Anti-blooming (ABG) correction OFF

Submit observations (images and astrometry, and/or photometry or spectroscopy).

Upload images to the Target Asteroids!

ftp site at

Connecting to the ftp site for the first time:

  • Click Start
  • My Network Places
  • In Network task pane click “Add network place” (Add network place wizard will begin)
  • Click next to continue
  • Chose “another network location”
  • Next
  • Type or copy in the network address box
  • Next
  • Chose “log on anonymously”
  • Next
  • Type a name of your choice for this ftp site
  • Next
  • Finish

This will set up an icon in “My network places” from which you may connect directly to the public ftp site in the future and take you to the ftp site.

Copy image files from your local computer and paste into the ftp site window. Click “X”to exit. After this, you will only have to click on the icon in “My Network Places” to connect.

The suggested image file name is in the format: Observer_Object_YYYYMMDD_HHMMSS_Flag(TA or TNEOs).FITS

For example: Hergenrother_1999RQ36_20120318_041510_TA.FITS

TA or TNEOs flag lets us know if you are a general or Astronomical League Target NEOs! observer. Astrometry data should be submitted also to the MPC in the appropriate format.

(Images are transferred immediately to folders for Target Asteroids! Co-leads. So don’t worry if they seem to “disappear” after uploading.)

Email astrometry or photometry data to

Use the Minor Planet Center format for your reports. Some software packages automatically output in this format.

For example:

	COD H06
	CON M. Nissinen, Kauppakatu 70 A 10
	CON 78200 Varkaus, Finland []
	OBS M. Nissinen
	MEA M. Nissinen
	TEL 0.43-m f/4.5 astrograph + CCD
	NET GSC 1.1 (corrected)
	ACK measurements of E1018 141018 2001 WC47.
	NUM 3
	E1018 C2012 04 21.16863 11 48 12.72 +32 20 12.0 H06
	E1018 C2012 04 21.17934 11 48 15.36 +32 19 42.3 H06
	E1018 C2012 04 21.20296 11 48 21.18 +32 18 35.5 H06

Obtain additional Information as needed.

Refer to the Target Asteroids! Frequently Asked Questions (FAQs) page for more detailed assistance and helpful links to additional information about observing asteroids.

To contact the Target Asteroids! Co-leads: Dolores Hill or Carl Hergenrother, email

For more information about the mission, visit the OSIRIS-REx mission website:

Target Asteroids! Partners

  • Association of Lunar & Planetary Observers
  • Astronomical League
  • Catalina Sky Survey
  • International Astronomical Search Collaboration
  • Mt. Lemmon SkyCenter
  • NASA Night Sky Network
  • Oceanside Photo & Telescope
  • Sierra Stars Observatory Network