I started timing total occultations using a clockdriven 6-inch Newtonian (very excellent mirror, I may add) in the year 1960. Since then, I've timed 1,189 Zodiacal Catalog stars and 588 non-Z.C. stars, and observed 103 grazing occultations, all this up to 11/12/96. My specialties over the years have been to successfully lead graze expeditions and draw very detailed Pictorial Reductions (P.R.'s for short) of graze observations, some of them published in I.O.T.A.'s Occultation Newletter (i.e., O.N.). Some of these P.R.'s are of grazes I have not personally observed, but are of other expeditions, like clear over in the country of Spain, etc.
Back in the year 1970, L.V. Morrison at the Royal Greenwich Obs., Her Majesty's Nautical Almanac Office (at Greenwich, England) in the "Monthly Notices of the Royal Astronomical Society", Vol. 149, PP 81-90, published an analysis of Dr. C.B. Watts lunar charts called "The Marginal Zone of The Moon", Astronomical Papers of the American Ephemeris, Vol. 17, U.S. Government Printing Office, Washington, D.C., 1963 (no longer in print). This is a tome which shows the lunar limb corrections in relation to the moon's mean limb for every 0.2-degree interval around the entire 360-degree circumference. Morrison's analysis showed that the late Dr. Watts (1889 to 1971) had errored with regard to the axial orientation of the lunar features This analysis showed that Watts was off by 0.25-degrees, +/- 0.01 degree for each one of his 1,800 charts (i.e., one chart for each 0.2-deg.)!! I felt honored when I realized (at the time) that 3 of the 38 observed grazes used in the analysis were of graze expeditions that I had led, and also of the 38 grazes, I had drawn 4 P.R.'s vividly showing the Watts' discrepancy PRIOR to the analysis (mentioned in this paragraph) being published!!
(1) Northern limb graze of Taygeta (one of the Pleiades stars) on 8/06/69, when Harold Povenmire and I noticed that the star distinctly stepped ON several times during the graze. The star was NOT known to be a binary star PRIOR to the graze, or if it was, the double-star datum was left off of IOTA's limit prediction heading!!! I believe that I have discovered at least 3 binary stars since 1969, another one being 4.8-mag. Chi Virginis on 12/31/88.
(2) Two southern limb Partial-Cassini Region grazes of 4.0-mag. Rho Sag. = ZC 2826 that I first observed near Proctor, Oklahoma on 11/25/76, and then again just south of Jackson, Mississippi on 9/5/95. Many expeditions were "out" for BOTH grazes, and all the timings acquired greatly refined the lunar profile in the Watts angle region of 166.2 to 175.0. Unfortunately, though, the company I work for would not allow me to make my THIRD successful graze trip for Rho on 11/26/95, so I have yet to see THREE grazes of the same star, and if it is to be Rho, I will probably have to wait til about 18 years from 9/05/95! Note: It is this writer's opinion that certain stars seem to be associated/dependent with certain Latitude Libration VALUES (explanation). For instance, the Rho Sag. graze on 11/25/76 occurred at Watts angle of Central Graze centered at approx. 170.2-deg., and Long. (L) and Lat. (B) values of +6.0 and -6.0, respectively, while the graze of Rho on 11/26/95 occurred at W.A. of C.G. centered at approx. A.A.of C.G. = 170.2-deg., and L & B were +0.3 and -6.0, respectively, or IDENTICAL latitude librations!!
(3) Two northern limb grazes of 6.1-mag. 26 Arietis = ZC 370 that I first observed near Chugwater, Wyoming on 8/22/70, and the second time near Warrensburg, Missouri on 9/09/90, OR slightly OVER 20-years apart AND many miles apart!! Again (as mentioned for Rho Sag., above), certain stars seem to be associated with Latitude Libration; the ZC 370 graze on 8/22/70 occured at Watts angle of Central Graze of 344.3-degrees, and L & B were +7.9 and -6.0 degrees, respectively, while the ZC 370 graze on 9/09/90 occurred at Watts angle of C.G. of 351.4-deg., and L & B were -0.2 and -6.0 degrees, respectively, OR IDENTICAL latitude librations!!
(4) Also observed what we have to call PARTIAL occultations of BOTH planets Uranus on 2/10/77 UT (very challenging, I might add) by 4 observers against the 58% sunlit moon, and the other of Saturn on 11/13/67 UT in northeastern Kansas, moving along the 86% Waxing Moon's southern limb. Observers from all over the U.S. conjugated near Seneca, Kansas, including Dr. David Dunham and several others from the U.S. Naval Obs. to observe the event. Although NO valuable scientific data can be derived from viewing astronomical events like these, they sure are impressive. With the case of Saturn, I was on the Central Line, whereby I saw one-half of Saturn's ball behind the Moon's mean limb, and the other half visible.
(5) After several past attempts (since about 1965, I think) at observing a grazing occultation of a "known" double star (only to be clouded out), I successfully observed 6.4-mag. Double Star 207 B. Aquarii = Z.C. 3326 (components 6.7 and 7.8-mag., and separated by only 0.3" in relation to the moon. This graze occurred along the near Cassini southern limb. Although there were only a total of 4 observers who saw this graze in two different expeditions, we could say that there were 8 observers, since they made accurate timings of both components!! It might be mentioned, that it's duplicity was discovered by David Evans during a photoelectric occultation observation at McDonald Observatory on Sept 29th, 1974.
(6) My first successful attempt at observing a star occultation by an asteroid occurred on 12/10/95 UT, when the 8.5-mag. (KO spectral class) star SAO 111235 was occulted by the 11th.-mag. asteroid 85 Io. David Dunham had ask me to observe it with the Astronomical Society of Kansas City's 30-inch Newtonian at Powell Obs. near Louisburg, Kansas. I got ON the "target" star just five minutes before the predicted Dis.-time, and noted a orange-colored star "dead-center" in the 68X eyepiece field, with many other (fainter) stars surrounding it. I fixated on the star, and then "bang",--- the star instantly disappeared from the field of stars for a eighteen-second time period, and while the star was invisible, the asteroid BECAME visible!!
(7) But really, fellow browsers of this Web Page, my greatest thrill is not only to observe grazing occultations, BUT to be able to draw Pictorial Reductions for a graze where several observers from SEVERAL graze expeditions seperated along the graze limit, observe the same graze!! It is interesting for me to plot ALL observers that successfully observed a particular graze, on the SAME Pictorial Reduction. As you "Browsers" should allready know, the more observers making accurate timings of star contacts with the lunar limb, the more refinement of the lunar features, and Bob Sandy just loves to show the results on P.R.'s!! Please keep in mind that I try to be very detailed to a point that it might take me awhile to finish a particular P.R. to my liking, and also the fact that the Occultation Program is strickly voluntary. I would be glad to draw P.R.'s for anyone who would not mind submitting to me a $5.00 check (to cover cost of photocopying and postage and handling) AND (of course) their I.O.T.A. Formal Graze Report in the snail-mail, along with their check.
MAY THE OCCULTATIONS BE WITH YOU.
Bob Sandy; 490l S. Valley View Rd.; Blue Springs, Mo. 64015; U.S.A. E-mail address: bobgraze@sbcglobal.net (I would like your comments sent to this address) Home Phone: 816-795-8116