In the 1920s, the International Astronomical Union established the Central Bureau for Astronomical Telegrams as an announcement center for new astronomical discoveries of objects such as comets, novae, supernovae, etc. Since the 1960s, the Bureau has been operated by the Smithsonian Institution's Astrophysical Observatory at the Harvard/Smithsonian Observatories in Cambridge, Massachussets.
Today, the main publication of the CBAT is called the IAU Circulars, available in both printed form (via postal mail) or electronic form (via e-mail or the CBAT computer service). IAUCs are published irregularly, as required, typically 200 or so per year. A number of other publications deal with minor planets and cometary orbits. Further information about these publications can be obtained from the CBAT at SAO, 60 Garden Street, Cambridge, MA 02138. Contrary to the Bureau's name, they no longer issue announcements via telegram.
Before You Report
If you think you have found a new comet, nova or other object, there are certain steps you should take before reporting your discovery:
Be absolutely certain the image is real.
This may sound trivial, but reflections off optical surfaces, photographic film defects, defective pixels in CCD arrays and electronic noise have all been reported over the years. Move the object around within the field of view. Change eyepieces and observing positions. Make multiple photographic or electronic exposures. In each case, slight changes in the optical system or exposure should leave the object fixed against the background field stars.
Examine the object at high power.
A fuzzy object at low power may resolve itself into a faint grouping of stars at higher magnification.
Check a good star atlas for any galaxy, nebula or cluster near the object's position.
Check several different sources. Even the best single atlas may contain omissions or mis-plotted objects. Find and identify any known objects that are nearby to confirm that they are not the suspect.
Check the field for motion.
Carefully sketch the field of view, noting in particular the suspect's position relative to identifiable stars. Note the time and date (UT only, please) of the sketch. Sketch the field again after at least an hour. Note, again, the time and date. Did the suspect move? Be skeptical if no motion is detected. Try to find the object a night later and sketch it a third time to detect motion. Better yet, get a few of your colleagues to confirm your object by independent observation.
Estimate the total brightness and any detectible size and orientation.
Do this each time you make a field sketch.
Check published lists of any known comets or minor planets.
This is a good way to pass the time between observations. Astronomy's Sky Almanac or Sky & Telescope's Calendar Notes and Observer's Page are probably the most readily available sources. The IAU Circulars and ALPO's Minor Planet Bulletin and the annual Handbook of the British Astronomical Association are other good sources.
Making the Report
If your discovery passes all the tests above, it may well be a new object. Report your find by telegram to CBAT: TWX 710-320-6842 (answerback ASTROGRAM CAM). Include your full name, street address and phone number where you can be reached. List the date, time, right ascension and declination (including equinox used -- they prefer 2000.0), magnitude and appearance for each observation. (That's why you noted all those things when you were trying to confirm its existence.) Then give the details of your equipment (telescope, aperture, magnification, film or CCD type and exposure times), observing location and any other observers who may have confirmed the object with you. Airmail the same information to the address given earlier as a backup.
A sample telegram below shows the preferred way to make a report. It uses the official IAU code which has long been used for a variety of astronomical discoveries. This fictitious case reports a sighting of a new comet by Amanda Jones on March 23, 1995. She saw a short tail, but no sign of condensation around a nucleus.
JONES COMET JONES SMITH20001 50323 25000 09589 20022 01115 45550 3072620001 50324 12500 10018 10201 01115 23659 21334VISUAL OBSERVATIONS WITH 20CM REFLECTOR AT GALAXY MOUNTAINNEAR COMET WEATHERBEEDISCOVERER AMANDA JONESGEORGE SMITH, 23 SKYVIEW LANE, ANYTOWN, FUNNYSIDE ISLANDPHONE 111-222-3456
The first line gives the discoverer's name, type of object and names of all observers (Jones and Smith in this case). Next, two observations of the comet are given, each represented by a line of 5-digit numbers. The first line is deciphered as follows:
20001 gives the equinox (2000) with a single digit to indicate the accuracy ( 1 = rough, 2 = precise).
50323 gives the date in year-month-day format. Only the final digit of the year is given. 25000 is the time of observation given as decimal of a day to five digits.
09589 is the right ascension in hours, minutes and tenths of minute. 20022 is the declination in degrees and minutes of arc. The initial digit is always either 1, meaning - or south, or 2, meaning + or north.
01115 reports how the comet looked. 01 indicates total magnitude (02 = nucleus only); 11 is the magnitude rounded to nearest whole number; 5 indicates the degree of tail and condensation.
The last two groups are check digits to determine if any of the data was garbled in transmission. 45550 are the last five digits of the sum of the first 6 groups; 30726 is the sum of groups 4, 5, and 6 alone.
Further details of reporting formats for comets, novae, minor planets and others are available from CBAT at the address given above.
