Occuttau'mgNewsteuer Volume II, Number 7 December, 1979 Occultation Newsletter is published by the International Occultation Timing Association. Editor and Compositor: H. F. DaBo11; 6 N 106 White Oak Lane; St. Charles, IL 60174; U.S.A. Please send editorial matters to the above, but send address changes, requests, matters of circulation, and other IOTA business to IOTA; P.0. Box 596; Tinley Park; IL 60477; U.S.A. FROM THE PUBLISHER tions for monitoring small variations in the solar radius. Prospects currently look good that Alan Fla- For subscription purposes, this is the first issue la, USNO, and I will receive support to travel to of 1980. India to observe the eclipse from both limits, and to organize efforts by local observers to supplement o.n.'s price is $1/issue, or $4/year (4 issues) in- our observations. I have received quarter-time sup- cluding first class surface mailing, and air mail to port from Sabatino Sofio, Goddard Space Flight Cen- Mexico. Air mail is extra outside the U.S.A., Cana- ter, to pursue work with eclipse-edge observations, da, and Mexico: $1.20/year in the Americas as far especially to search the literature and various ar- south as Colombia; $1.68/year elsewhere. Back is- chives for possibly useful observations of previous sues also are priced at $1/issue. Please see the eclipses. masthead for the correct Mering address. I already have received a number of responses to the IOTA membership, subscription included, is $7/year article about Royal Greenwich Observatory's planned for residents of North America (including Mexico) discontinuance of most lunar occultation work in o. and $9/year for others, to cover costs of overseas n. 2 (S) 42. Reports of lunar occultations observed air mail. European (excluding Spain and Portugal) during at least the first half of 1980 should still and U. K. observers should join iota/es, sending be sent to the Royal Greenwich Observatory (RGO). DM 12.-- to Hans J. Bode, Bartold-knaust Str. 6, Hopefully, another institution will be available to 3000 Hannover 91, German Federal Republic (but see collect the 1980 year-end reports. the first paragraph of IOTA NEWS for change of ad- dress effective 1980 January I). Spanish, Portu- Any institution seriously interested in assuming guese, and Latin American occultation observers may many of RGO'S current lunar occultation responsibil- have free membership in IOTA/LAS, including Occulta- ities should send the person who will direct the tion Newsletter en EspaMl; contact Sr. Francisco work to RGO for a few weeks to become intimately fa- Diego Q., Ixpantenco 26-bis, Real dc Ids Reyes, miliar with the current system and obtain copies of Coyoacdn, Mexico, D.F., Mexico. computer programs which might be converted from use with RGO's to the new institution's computer. Dr. IOTA NEWS Wayne Osborn, Physics Department, Central Michigan University, has volunteered his department for the David W. Dunham collection and preliminary reduction of the observa- tions, if there would not be too much difficulty in European Section members should note that, starting converting the appropriate part of RGO's software to 1980 january 1, Hans-joachim Bode's address will be: run on their new large CDC computer. He says that Bartold-knaust Str. 8, 3000 Hannover 91, German Fed- they will not be able to produce graze maps, a job eral Republic. Only the street number has changed with which IOTA probably can help. The question also (from 6); his telephone remains 0511-42 46 96. was asked as to to who is leading an effort to find a replacement for RGO'S work. I suppose, by default, It has been mentioned in an earlier issue that Hans- that would be RGO; if any other institute volun- Joachim Bode will attempt to observe the 1980 Febru- teered to lead a search effort, it would become a ary 16 total solar eclipse from a location near the prime candidate for (even obligated to) taking on southern limit in Kenya, and encourages others to all of the work. I think that RGO would prefer that join him in this effort. At last August's I.A.U. a government organization with 1ong-tem support, Genera] Assembly, Dr. A. M. Sinzi told me that Jap- such as one of the Nautical almanac offices, take on anese astronomers plan to obtain cinematography of the work. But if that is not possible, a university the flash spectrum from three locations in Kenya, would be better than a largely amateur organization, one near the central line, and the others just in- such as IOTA. Note that Yale University was the . side the predicted limits. I plan to compute accur- world center for occultation work for many years, ate offsets of the actual limits, based on the lunar but at a time when there were many fewer observers, profile and other refinements, from the U. S. Naval and when computers were not as ubiquitous as today. Observatory's circular-moon published predicted lim- I think it probable that any institution taking on its, within a few weeks, and will provide the data the work would appreciate the help of regional coor- to anyone who might be interested in observing near dinators, for which we already have some volunteers. the edge of the path. Solar physicists have become Victor Slabinski has suggested that observers be en- very interested in using eclipse path-edge observa- couraged to submit their observations in keypunched W V 62 form, when possible, the reward being that such ob- vice and simultaneously time occultations visually, servers would receive residuals of their observa- to study reaction times and observers' ability to tions quickly with the need for institutional key- estimate them. I can think of a couple of useful punching eliminated. This may have some merit, but I modifications of the device: I) Allow it to record feel that, in addition, a paper report on the adopt- two times at two different levels, one just below ed report forms must also be supplied in every case. the full star intensity and the other slightly above RGO always has resisted the idea of observers key- the background level, to detect close double stars; punching their own observations, due to the variable 2) Allow it to record two (or several) times at the quality of the keypunching job that would result, same level, so that it might be used for asteroidal and a consequent possible large expenditure of time and lunar grazing occultations. Mr. Hansen now is to identify and correct keypunch errors. In short, testing the system on lunar occultations, and plans they feel that they would lose control if such a to publish more details and results in a future is- step were taken. But some economies probably will be sue of Occultation Newsletter. necessary in the future, and as keypunch machines become more ubiquitous, observers increasingly may During the night of October 26, when the waxing be asked to look at their computed residuals and crescent moon passed through a rich southern Milky correct their own keypunch errors. Way field, Graham Blow reports that he timed 66 dis- appearances, a record for one night, as far as I I recently have written a computer program which know. Many of the stars weren't even in the j-cata- computes local circumstances for asteroidal and log. Mr. Blow also reports that members of the Oc- planetary occultations. For each input event, the cultation Section of the Royal Astronomical Society time (U.T.) and distance (in arc seconds, kilome- of New Zealand are working on an occultation manual ters, and occulting object diameters) of closest ap- which they plan to publish in sections in various proach are computed, along with the altitude and az- issues of their circular during ]980. IOTA might imuth of the occulted star, the sun, and the moon. adopt some of this work for its own manual. No data are printed if the star is below the horizon more than an amount which is proportional to an es- Now that we are approximately on schedule (actually timate of the occulting object's along-track (time) ahead of schedule, for the first time, I believe) error, or if the star is fainter than 6th magnitude with the publication of o..v., perhaps we can estab- for a daytime prediction. These local lists are lish, and stick to, a schedule for future issues. meant to supplement the general lists of all events The next issue should be distributed in late March, published in o.n. (such as on pp. 63-65). Although to give the latest information about the April 6th I've created it, I don't want to use it (at least occultation by Pluto. To do this, information on new not very much), and would like a volunteer to adapt double stars, grazes, and erroneous star positions the program to a local computer, to offer this serv- should be sent to Dunham and to Herald by February ice to all IOTA members, and to others on a request 25th, and articles should be received by the editor basis for a fee (probably SI per year). iy March 5th. In the most recent issue of Telescope Making, Rus- PLANETARY OCCULTATION PREDICTIONS sell M. Genet has published a good article entitled "Fairborn Observatory: It's Equipped for Photoelec- David KL Dunham tric photometry." First, Genet discusses the basic requirements for a photoelectric telescope system, Predictions of occultations of stars by major and then goes into the design of his telescope, observa- minor planets, and one of the former's satellites, tory, photometer, and supporting equipment.