I Occuttau'ongNewsteter Volume V, Number 6 Decedjer, 1991 ISBN 0737-6766 Occultation Newsletter is published by the International Occultation Timing Association. Editor and compositor: Jom Bixby Dunham; 7006 Megan Lane; Greenbelt, MD 20770-3012; U. S. A. Ple8se send editork1 matters to the above, Send new and renewal memberships and subscriptions, back issue requests, address cknges, graze prediction requests, reimbursement requests, special requests, and other IOTA business, but not observation reports, to: Craig and Terri McManus; 1117 Collins; Topeka, KS 66604-1524; U.S.A. FROM THE PUBLISHER IOTA NEWS For subscription purposes, this is the fourth David VI. Dunham issue of 1991. It is the sixth issue of Volume 5. This Issue and 1992 Pknetary Occultations: The min purpose for this issue is to distribute my , IOTA annual membership dues, including On. and sup- plements for U.S.A., Canad8, and Mexico $25.00 predictions for planetuy, 8$teroid&1, and cometary for all others 30.00 occdtations that will occur during 1992. Unfortu- Annud IOTA membership dues my be paid by check nately, my many prediction oblimtions and the drawn on an American bank, money order, cash, or by holidays will make distribution of this issue late, charge to Visa or MasterCard. If you use visa or sothu most subscribers will receive this dter the MasterCard, include your account number , the expim- first few events occurred. Most, but not all, of tion date, 8nd your signature. these early events were covered in E. Coffin's ON, subscr iption (I year ' 4 issues) predictions distributed earlier, or in my article for U.S. 4., Canada, and Mexico 20.00 starting on 9. 72 of the 1992 jzujary issue of Skv- for all others 25.00 and Telescope (S&T). It was not possible to assem- Single issues are 1/4 of the price shown. ble this issue before departure for our 2-week Altlloull they are available to IOTA mbers without ¢haue, holiday vacation, which will include trying to Dmed)erg wGt pay for tliue items: observe the annular eclipse in California. So the Local cireustaoee (uteroidal appuhe) predicti006 (for your issue will either be 8ssembled and printed while we loutioo) " 1.00 8re 8w8y, in which case it My look a little unusuM Graze liuit ad profile predictim (per µue) 1,50 since it Yi]] not be possible to reprint p89es to Papers explaioiu the UbC of the predictioas 2,50 make figures 8nd text fit well. Or it will be Asteroidal occultatioo npplaeots will be available at extra ¢OGt: assembled, printed, and finally mailed mmy days after we return on jan. 6, in which use you will _ ¶eoeujeia),for South Aoericafor hropethroughthrough[gnacioRolaodFerriobooiuuu(Apartado(Rue700;dcKeridahriabourg,5101"A; get it we]] after the middle of january, dter many 33; 8"6381 DOURBLS; BeibiUH) or IOTA/IS (6cc below), for southero good events have passed. Africa throuth K. D, Overbeek (Box 2]2; Bdeovale 1610; Republic of South Africa), for Australia aod Kev Ieahod throuh Craha6 Blow (LO. Don Stockbauer 8nd Tony Murmy have not suNittod Box 2241; Felliuton, Ku Ieahod), aod for Japao through 7oshio articles on grazing occultations 8nd new double Bime (1"13 Shimaruko 1"chne; 0ta"ku, Tokyo 146, japu). Supple" stars for this issue, since too few reports have neats for all other areu will be available fm jiw Stm (117891 K. been received since the last issue. Robert Xndy joi Drive; hem, AI 85731; ILSA.) for $2.50. notes grj error in the graze list on p. 108 of the 0bnrvm frn lurope ud the kitiU i6le8 should joia m/is, last issue; his expedition for the june 17th graze mdiu OIl 40,-- to the aceouot I07A|LS; Bartold"kiut Straue g; us 8t Peculiu, IK) (not KS). 3000 Bmover 91; PoGtkir0 hooover $55 $29 - 303; baok"code"nUer (Baokleitzahl) 250 100 30. IOTA Meeting: The next (10th) annuM meeting of the International Occultation Timing Association will probably be held Saturday, 1992 October 3, in the 129 . 130 Houston, Tcx8$, area. This will give those who reported. If a definite occultation is seen th8t arrive early a chance to observe two good grazing could use some analysis for comparison with others, occu1tations that will occur in the area Thursday also send copies of the report to inc at 7006 Megan evening, October 1st (U.T. October 2). The Moon Lane; Greenbelt, MD 20770; U.S.A., and to the viii be 35% sunlit w8xiM, and the grazes 8re d8rk- chairmn of the Intermtioml AstronomicM Union's 1i±southern-limit events. Thestars are 6.3-mag. (I.A.U.) Comnission 20Working Group on Predictions ZC 2510 and 4.3mnag. 44 Ophiuchi. The p8ths 8re ofOccu1t8tion$ by S8te11ite$ andMinor Pknets, who shown as numbers 284 and 285 on p. 124 of the RASC is LawrenceWasserman; Lowell Observatory; Mars Hill Observer's Handbook, and the 44 Ophiuchi event is Road, 1400 West; Flagstaff, AZ 86001; U.S.A. Usd shown on p. 68 of the january issue of S&T. Alternatively, observers may send their reports to The 1omtion of the meeting has not yet been deter- their 10¢81 or regional coordimtors, who cm then mined, since our usual meeting place, the Lunar and sendthe resultstoStamn, and, when appropriate, to Planetary Institute, will probably not be availab1e Lovell Observatory. The addresses of the regional during weekends in their new location. More specif- coordinators are given in "From the Publisher" on p. ic informtion will be given in either the next 129 of this issue. Forms for reporting the observa- issue, or the one following it. tions can be obtained fromStamnor fromthe region- al coordimtors. Ple8se indicate on the forms to ._ Graze Supplements and Next Issue: i had planned on whom copies are being sent. These forms are pre- distributing the hemispheric grazing occultation ferred, but the forms of the lnternatiom] Lunar supplements for 1992 with this issue, but this will Occu1tation Centre (ILOC), or the equivalent not be possible; it was more important that I spend 10TA/ILOC graze report forms, c8n be used for my limited time on distribution of the detailed IOTA reporting timed occultations or appulses. The main grue predictions for early 1992, and related data difference from reporting lumr events is that the for others helping with this effort. We plan to name of the occulting body should be written promi- distribute the grue supplements in a separate nently 8t the top of the form, and the report should nailing in january. We hope to produce the next be sent to neither ILOC in japan nor to Don issue of ON. in mrch. If you have a contribution Stockbauer. Also, if the 8steroid is visible, the for that issue, we should receive it by March 7. timetkt it merged with the star to formone 8pp&r- ent object, and the time the two were again notice- ably separated, should bereported, with an estimde SOLAR SYSTEM OCCULTATIONS DURING 1992 of whether the asteroid passed north or south of the star, if possible. Copies of the ILOC forms c8n be David W. Dunham obtained from ILOC, the IOTA secretary-treasurer (the MCM8MjSCS in Topek8, KS), or from Don g,n,e,r,a.1,: My predictions of occultations of stars by Stockbauer; 2846 Mayflower Landing; Webster, TX major andminor planets, and by onecomet, are given 77598; U.S.A. — in two tables whose contents are described in ON, S, No. 2, and in subsequent sections of this article. Event Selection: I made computer comparisons of my Kost of the asteroih1 occu1tation prediction combined caU1og with ephemerides of all of the m8teria1 distributed by IOTA was prepared by Edwin major planets, the gi8nt comet P/Schwassmann- Coffin in Belgium and is discussed in the third Wachtnann 1 (P/SnrWm"1), and all minor planets for section, Sources of the predictions, other informr which Edwin Goffin predicted (see section below) 8t tion, including stellar diameters (when significant) least one event under the selection conditions that 8nd 8 priority list, and notes 8bout individual we used for the min put of the North Amerian events, are given in the last sections. Asteroidal Occultation Supplement for 1992: The star must be brighter thm mag. 12.6; the magnitude ReportinA Observations: Reports of observations of dropmust be at 1mt 0.5; and for angular diameters any of these events should be sent to jim Stamn; smaller than 0:021, the star must be brighter than 11781 N. joi Drive; Tucson, AZ 85737; U.S.A. mag. 5.1; 0:021 to O:OSO, brighter than mag. 6.1; Report O:'OSi to 0:060, brighter than mag. 7.1; 0:061 to positive or negative observations made under good o:on, brighter than mag. 8.1; and (1'071 to (1'079, conditions, but clouded-out 8ttcmots need not be brighter than mg. 9.1. In a few cases, these 131 conditions were violated, such as for interesting this issue. objects like 44 Nysa, 624 Hektor, and 2060 Chiron. The numbers of the minor planets includod in iny Ccmpuison with the True Visual Magnitude Atlas cmbined cata1og searches included 1-4, 6, 10, 13, (TVMA) often shows that some FAC st81% are brighter, 15, 17, 18, 20, 21, 24, 27, 29, 30, 34, 36, 38, 40, fainter, or very faint relative to their plotted 41, 44, 47-49, 51, 52, 54, 58, 68, 70, 80, 84, 86-8, mgnitudes, indicated with B, F, or VF, respective- 92, 94, 103, 105, 115, 117, 121, 137, 139, 144, 145, ly. "N" indicates that the star is not shown in 154, 164, 165, 175, 184, 192, 194, 212, 216 (unfor- TVKA, tunately, noevents were found), 230, 248, 276, 308, 324, 334, 344, 349, 409, 410, 429, 451, 455, 469, For mny asteroids, Goffin used orbital elements 490, 511, 524, 532, 584, 596, 624, 626, 654, 704, published in the Minor Planet Circulars (MPC'S) 804, 805, 914, 2060, 3123, and 3148.