g . T Occutmion@Newstetter Volume III, Number 8 August, 1984 Occultation Newsletter is published by the International Occultation Timing Association. Editor and compos- itor: H. F. DaBo11; 6 N 106 White Oak Lane; St. Charles, IL 60174; U. S. A. Please send editorial matters, renewals, address changes, and reimbursement requests to the above, but for new memberships, new subscrip- tions, back issues, and any special requests, write to IOTA; P. 0. Box 3392; Columbus, OH 43210-0392; U.S.A. FROM THE PUBLISHER ufacturer will be sought for the system after the changes have been tested. Chen also hopes that the For subscription purposes, this is the second issue reduction software can be converted to run on micro- of 1984. computers, so that this work also can be done inde- pendently. Those planning to attend the IOTA meet- When renewing, please give your name and address ex- ing should contact Paul Maley, 15807 Brookvi11a, Y .~ actly as it appears on your mailing label, so that Houston, TX 77059, U.S.A., telephone 713,488-6871, we can locate your file; if the label should be re- vised, tell us how it should be changed. Some problems with last year's graze predictions were described in o.n. 3 (4), p. 81 & 89. The prob- o.n.'s price is $].40/issue, or $5.50/year (4 is- lems have not been corrected, and the differences sues) including first class surface mailing. Back between the 80F (or BOG) and 78A USNO prediction issues through vol.2, No. 13 still are priced at versions are even greater this year. , For waning- only $1.00/issue; later issues @ $1.40. Please see phase northern-limit grazes with latitude 1ibration the masthead for the ordering address. Air mail greater than zero, you should apply (to the ACLPPP shipment of o.n. back issues and subscriptions, if profile, which is based on version 78A) the correc- desired, is 45¢/issue ($1.80/year) extra, outside tion om x (lat. 1ibration in degrees), as des- the U.S.A., Canada, and Mexico. cribed in o.n. 3 (S), p. 100 (observations of two grazes this July seem to indicate this is the best IOTA membership, subscription included, is $11.00/ way to proceed so far this year). The 1983 observa- year for residents of North America (incltiding Mexi- tions were not numerous enough to solve the problem co) and $16.00/year for others, to cover costs of definitively, and things could happen a little dif- overseas air mail. Observers from Europe and the ferently this year, so preliminary information about British Isles should join I0TA?ES, sending DM 20.-- observations of any waning northern-limit grazes to Hans-j. Bode, Bartold-knaust Str. 8, 3000 Hanno- with large HEIGHT values during the next two months ver 91, German Federal Republic. will be valuable for deciding how to deploy for events during the following months and next year. IOTA NEWS If you plan a large expedition, get the latest in- formation about the shifts from me; around full David W. Dunham moon, I will leave a message giving reconnendations on our answering machine at 301,585-0989. - This year's meeting of the International Occultation Timing Association will be held at the Lunar and Other important news that might ordinarily be found Planetary Institute, 3303 NASA Road One, Houston, here is covered in two other articles of this issue, Texas 77058, on Saturday, October 20th. The loca- entitled "IOTA/ES News" and "Asteroidal Occultation tion is the same as last year's meeting. The meet- News." You should read both, whether you are a mem- ing will begin at 10 am Central Daylight Time, and ber of IOTA/ES or not, since the first article has will last most of the day. The following topics are some information which may be of interest to all on the agenda: Observations of the May 30th annular IOTA members. eclipse; final plans for the November 22nd total so- lar eclipse; plans to observe occultations during Also, residents of the U.S.A. should notice the dis- the 1985 May 4th total lunar eclipse from or near cussion about deducting travel costs from their in- Africa, including the simultaneous north-south graz- come when calculating their 1984 taxes, near the end es of 2.9-mag. Zubenelgenubi (Alpha Librae) during of the article about the May 30th solar eclipse. totality; other interesting occultations, especially That discussion also applies for travel to observe by asteroids, during 1985; and preliminary plans to grazing occultations or asteroidal occultations. observe Halley's Comet from southern Africa in 1986. Ne also will have some discussion about photoelec- IOTA Special Bulletin Number 8, containing informa- trica11y recording occultations, perhaps including a tion about asteroidal occultations in July and Aug- WolfgangcomparisonBeisker,of the Germanis in thephotometerU.S.A. for(thea year?desi ner,with ust, was distributed as a stopgap measure when un- foreseen difficulties prevented preparation of this the Chen photometer. Peter Chen tells me that his issue in time. 1Ae plan to distribute the next issue system is being redesigned somewhat to include more in 3 to 4 weeks, to include the material which would off-the-shelf components, to improve the reliability not fit in this or previous issues, and more infor- and decrease the need for repairs in Austin. A man- mation about grazing occultations, including some ""U 158 I ¢, more reduction profiles by Robert Sandy, Independ- servatory, TX. There was a gap in the laser obser- i ence, MO. o.n. 3 (IQ) is scheduled tentatively for vations when problems were encountered with the ded- late November. icated ranging facility at Haleakala, HI, and a new smaller system at McOonald. As the electronics are MORE ON THE GRAVITATIONAL CONSTANT improved, it should be possible to make regular lu- nar laser ranging observations wIth telescopes with David Id. Dunham apertures smaller than 1 meter, which will permit more observatories to participate in this important The statements which I made about the non-variabili- program. That also will result in more accurate de- ty of the gravitational constant in o.n. 3 (6), 118, termination of earth polar motion and U.T. based on analysis of the Martian lander radio rang- ing data, appear to be an oversimplification of the Time is on the side of lunar occultation and laser actual situation. When small effects due to general ranging observations, since h is proportional to relativity are studied, the natures of the observed time squared. Hence, the determination will become quantities become important. The various cosmologi- much more accurate in the future. A good determina- cal theories predict different results if the ob- tion of the "space-like" rate of change of the semi- servables are "space-like" (predominantly measure- major axis (mean distance) of the lunar orbit will ments of distance) or "time-like." For example, Di- be made from the laser data during the next several rac's large-numbers hypothesis predicts a changing years. Lunar laser ranging probably will have the gravitational constant for "time-like" measurements final word in the gravitational constant controver- but not for "space-like" measurements. sy, as good "time-like" and "space-like" determina- tions of cosmological parameters are obtained. Lunar occultation timings are "time-like" measure- ments. Hundreds of revolutions of the moon have I thank Tom Van Flandern and lunar laser ranging pi- been observed, and the observed quantity of in- oneer Carroll Alley, Department of Physics, Univer- terest is n, the rate of change of the lunar mean sity of Maryland, for discussions which were most motion, or more precisely, the mean angular motion valuable for preparing this article. in ecliptic longitude. There are both tidal and cosmological contributions to the lunar ii, but the ASTEROIDAL OCCULTATIONS OF UNCATALOGED STARS, AND two can be separated using different types of obser- SOME NEMAUSA A.C. EVENTS, DURING 1984 vations, as explained by Van Flandern in his arti- cle, "Is the Gravitational Constant Changing?", in Robert L. Mi11is, Lawrence H. Wasserman, Otto G. the 1981 September 1 issue of Astrophysical journal Franz, Edward Bowell, Arnold Klemola, and David KL 248, pp. 813-816. He gives a value for the excess Dunham rate of change in lunar mean motion of possible cos- mological origin as An earlier version of this article was published as part of IOTA Special Bulletin Number 8, which was kiln = (+3.2 ±2.2) x 1q-ii per year, distributed to all o.n. subscribers. Events before August will not be included in the more legible list which results in published with this article, since they already have taken place, and none of them were observed, as far Gig = (-6.4 ±2.2) x 1q"11 per year, as we know. when interpreted with the scalar covariant cosmology Additional occultations of uncataloged stars by sev- of Canuto and Hsieh. en of the largest asteroids during 1984 have been found by scanning photographic plates at Lowell Ob- The accurate Viking ranging data primarily measure servatory. The techniques were the same as those distances, and are consequently predominantly used for a similar list of 1983 events published in "space-like." The data were accurate enough to mea- o.n. 3 (2), 25, except that the star positions have sure a cosmological change in the mean motion in been improved using plates taken at Lick Observa- spite of only about four revolutions being observed. tory. The 1984 events have been published by the This also could give a "time-like" measurement, ex- first four authors in Astronomical journal 89 (SL cept for one problem.