Occuthubn(Gnewstetter
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Occuthubn(gNewstetter Volume I, Number 3 January, 1975 Edited and Published by X. F, DaBoli at 6 N 106 White Oak Lane, St, Charles, Illinois 60174 U. S. A. GRAZING OCCULTATION TRACKS IN THE 1975 OCCULTATIDNS OF STARS BY (433) EROS 94 Pierce Rd., Watertown, Mass. 02172, OBSERVER'S HANDBOOK phone 6}7, 926-2678 Or 864-7360. In David It Dunham order to catch the event, it will be flue to an unfortunate error at the necessary to have observers at roughly printer's, the maps of the grazing qc- A map showing Brian Marsden's predic- even intervals across the whole region cu1tation tracks for 1975 were not in- tion for the path of the occultation of uncertginty. Observers are there- cluded in the 1975 Obgeme7"8 Hand- of Kappa Geminorum by Eros across fore urged to contact the above to co- book; the maps which appear are actu- southern Quebec, the northern tip of ordinate plans. ally those for 1974. We hope to pub- New Hainpshlre, and southern Maine is lish the correct maps in the February shown on p. 9 of the January issue of flue to the relatively low a?titude and Journal of the Royal Astronomical So- Sky and Telescope. Another prediction brtght moonlight, naked-eye observa- cietjjof Canada, and to send the maps was conputecf recently by Paul Herget tions will not be sufficient; at least to a interested observers. These at the Minor Ptanet Center at Cimin- smait binoculars or opera g7asses maps will be available early in the natl Observatory, According to Herget. which can be firmly held against a new year; please write to me if you the path is considerably farther post or other solid object will be would like a copy. , southwest, passing near Ottawa, Ontar- needed to make reliable observations. io; Massena, New York; Rutland, Ver- Binoculars and opera glasses are com- John R. Percy mont; and about halfway between Boston mon enough that appeals to the public Editor: Observer's Handbook and Providence, Rhode Island. Clue to fOr observations, via newspapers and R. A. S. C. the prediction uncertainties, it seems television, could be quite productive. 252 College Stmet that the approximately IS-mile-wide Dr. Clark R. Chapmen, Planetary Sci- Toronto ET 1R7, Canada path couTd cross any part of New Eng- ence Institute, 252 1L Ina Rd., Suite land, northern and eastern New York, I). Tucson, Arizona 85704, phone 602, southern Quebec, easternmost Ontario, 297-}176 or 297-4377, is preparing a Bermuda. any of the Caribbean islands suitable press release which will be south and east of the Virgin Islands, distributed when the area to be cover- eastern Venezuela, etc. Thomas Van ed is established. Local and regional Flandem at U.S.N,0. will comte an- coordinators can collect observations, other prediction, Early in January. and are encouraged to do so for obser- the predictions should be reconciled vations by the genera} public, which down to a 150-mile-wide corridor. will be more likely to respond if they Then, mrd will be disseminated to ail can report with a free telephone cali known observers in the areas mentioned than by any other means. Al] reports above and it should be feasible to co- scope,should 49-50-51eventuallyBayreachStateSk kd.,andCam-Tele- ERROR IN PARTIAL ordinate observations along parallel OCCULTATION PREDICTIONS tracks separated by 5 km, as described bridge, Mass. 02138, phone 617, 864- in the last issue. 7360. It should be stressed that nega- David 1L Dunham tive as well as positive observations Two regional coordinators are working are wanted. The observing period for Several partial occultaticms of plan- through the A.A.V.S.O. to help plan observers in eastern Canada to New ets by the moon have been observed us- observations in their areas. They are England should be from 7:)7 to 7:22 ing µredictions comuted with my com- George L. Fortier, M.D., 63 Devon Rd., p.m. Eastern StaRdard Time on Thursday puter program, establishing the accur- Bale d'Urfe. Quebec X9X 2hl7, phone evening, Jan. 23rd. If Eros is visible acy of most of the computed data. How- 514, 457-3533, and Alain C. porter, 10 in your telescope, start recording ever, during preparations for the par- Sea Lea Dr., Narragansett, Rhode Is- when the objects coalesce and stop tial occujtation of Mercury in Octo- land 02882, phone 401, 783-2336. The when Eros is separated from the star ber, I discovered that one of the in- A.L.P.O. Minor Planet Bu1,1,et,'i,n 2, p. again. terpolated points was about 3 miles in 23 gives John Allcock, aWMDuntain error. Observers should watch for pos- St., Montreal, Quebec H3G lz7, phone Dr. Seville Chapman, 94 Harper Rd., sible similar errors by plotting at 514, 844-1694, as a coordinator for Buffalo, n.y. ]4226, phone 716, 839- least four poiRts; if a straight line Quebec, but since he and Fortier are 1999, has designed and constructed q" gentle curve can be drawn through both members of the Montreal Centre of rather inexpensive equipment which can them, they should be accurate enough the R,A.S,C., they are presumably com- record the Kappa Geminorum occultation for prediction purposes. If not, check municating with each other. Dr. Edwin to better than 0501. The crucial item for plotting errors. If one point is B. Weston, 80 Oak St., Lexington, Mas- in this design is a United Technology still out of line, plot two or three sachusetts 02173, phone 617, 862-6148 PIN 3DP photodiode, available for of the uninterpolated points, which or 861-4040, is familiar with astro- $9.65 from [rondequo'it Industries, P. should be accurate. The error is rare nomical resources in Maine and New (I. Box 7637, Rochester, N.Y. 14622, and seems to be due mainly to the in- Hanpshire and is trying to encourage phone 716, 544-6257. Also needed is a terpolation procedure. ljnforturtately, observations there. Local coordinators fie7d effect transistor operational i win not have time to track down and mfght include Prof. Paul Mamet, Dc- anplifier; Dr, Chapman used an $18 correct this error during the next few partement dc Physfque, Universite Burr Brown 3522, but he says that a months, The interpolation procedure Laval, Cite Universftaire, Quebec 10, cheaper Fairchild type 740 could also for the calculation of occultation Quebec (a telephone number is not han- befeedbackused. resistorsSome 22-Metcostohm (oraboutgreater)lOt a- limits for stars is slightly improved dy, but the phone for Gaetan Chevalier, so that the error probably does not another Quebec City R.A.S.C. member, piece) and two 9-volt transistor radio occur with them. is 418, 524-6918) and Dennis di Cicco, batteries are also needed. The output b_ 20 COuld be recorded with a guod-qua1ity used for visual guiding). Field-test- ing the Sky and Tclescope map. In many tape recorder, Or (more likely) could ing the equipment on Kappa Geminorum of these cases, no occu)tations will be connected to a voitage-controiled before the night of the event will be be visible from the earth's surface, oscillator connected to a small loud a virtual necessity for success. Un- and for some others, Eros will be speaker (a small cassette tape record- fortunately, time is very short; any- brighter (depending on its phase) than er could record the resultant signal; one interested in building the equip- the star, making reliable visual ob- hNV or CKlj should also be recorded}. ment should request plans and parts by servations i@ossible. Without predic- Copies of plans to build the setup are telephone. The United Technology jjho- tions, the chances for any one Observ- available from Seville Chapman, Clark todiode might also be available from er to see an occultation are extremely Chapman, me, and probably the regional distributors in Toronto, Montreal, small, but if enOugh try, perhaps one coordinators listed above (they have Boston, or New York Ctty. The equip- will. If more than one observer In an been sent copies). The design is rath- ment could also be used to obta¶n pho- area tries to see these, they might er simple, so any amateur with a lit- toelectric records of lunar occulta- try to separate at intervals of about tle knowledge of electronics, able to tions, especially with larger (to get 10 miles in an east-west direction to buy the parts, and with a suitable fainter stars) amateur telescopes. increase chances. telescope and recorder, who is plan- ning to attenipt the occuitation of With a horizontal parallax of about Hopefully, the kappa Geminorum event Kappa Geminorwi is encoeraged to do so one minute of arc, it would be remark- will be more successfully observed pbotodectrically. With enough advance able if Kappa Geminorum were to be the than the occultation of a Rh-magni- notice, Seville Chapman has also ex- only star to be occulted as seen from tude star by (129) Antigone predicted pressed a willingness to loan his pro- the earth's surface as Eros careens a- for the southeastern United States totype to a responsible amateur pTan- cross the January sky. Judging from last October Rth. Generally clear piing observations from a location the chart on p. g of the january issue skies prevailed, but low altitude in within the predicted occultation zone of Sky and Telescope, it appears that Texas, a difficult-to-use finding with a 6-inch (or larger) telescope several close approaches to fainter chart, and little advance notice with drive. Dr. Chapman says that the stars might produce occu1tations some- caused problems, Probably over 100 equipent can be used with a small where.