The Best-Observed Lunar Grazing Occultations since the Last Meeting David Dunham IOTA Meeting, Stillwater, Oklahoma 2016 July 30

On 2015 June 22, we observed the northern limit graze of 5.1- mag. 48 Leonis at cusp angle 6N by 31% sunlit Moon; as reported at last year’s meeting, we were successful with two remote 80mm scopes that recorded 7 & 9 events. The path was only 30km north of Alice Springs. The view above shows the dry area with many desert oak trees where we observed. With only 1.5h of dark time, we set up 3 paver mounts the night before. The good profile promised good multiple events in a km-wide zone.

Probably the most interesting graze since the last meeting was the one that Dave Herald observed from Wallaroo, NSW, from a site only a few km north of our home at the time in MacGregor, ACT. He will discuss this record-setting event tomorrow morning. Joan and I didn’t have nearly as much action about 150 meters away. Because we had just moved into our rental duplex from a motel (and had also just returned from an arduous asteroidal occ’n multiple station deployment) only the afternoon before, we didn’t have everything together for a graze (needed different scopes) and also were late, so we didn’t do as well as Dave. I wasn’t able to get set up in time to observe it with our 10-inch “suitcase” telescope. As an aside, I’m not sure that Dave would have tried this graze on his own. Two nights earlier, there was a better graze (mag. 7.5, at northern cusp of 13% sunlit Moon, but not as good profile) that Dave had invited us to observe near Yass, NSW, about 15 km north of his home in Murrumbateman (he observed that event). But we declined since we were a few hundred km north, observing an asteroidal occultation n.w. of Dubbo that night. I noticed the SAO graze in our predictions and suggested a possible effort at Wallaroo, which Dave accepted, especially after he noticed the unusually good predicted profile. Only a few grazes have been observed by others, I think mainly by northern Californian observers R. Nolthenius, D. Breit, and T. Swift; they might say something about them during the questions period.

2016 April 15/16 Graze of 8.5-mag. SAO in cen. Maryland The LRO profile promised many events in a narrow range. The graze took place 4 deg. from the north cusp of the 59% sunlit waxing Moon.

2016 April 15/16 Graze of 8.5-mag. SAO in cen. Maryland We recorded several events from the well-placed north end of a commuter parking lot on the west side of MD32 north of I-70 using Wayne H. Warren, Jr.’s 8-inch SCT. But we forgot to bring an inverter, so we couldn’t power the clock drive, making many adjustments necessary.

2016 April 15/16 Graze of 8.5-mag. SAO in cen. Maryland The Howard (County) Astronomical League’s Alpha Ridge Observatory was near the northern edge of the full graze zone, so only an occultation by the highest mountain on the profile was seen there.

Antares Graze, Bardoc, W. Aus., 2009 Feb. 17 This set a record for the most distant graze expedition, from my home in Greenbelt, Maryland, USA to Bardoc, Western Australia, which is north of Kalgoorlie, home of one of the largest gold mines; it has a museum at the oldest continuously-operating brothel in Aus. The graze occurred 10 degrees from the south cups of the 41% sunlit waning Moon, one of the best of that series. 20, and to obtain two good color recordings of the red giant star and its bluish 5 th -magnitude companion, reminiscent of a spectacular graze of the star on the dark side of a thin-crescent Moon that Hal Povenmire, Ron Abileah, Eric Bram, and I observed in bitter cold weather in West Virginia in January But February is summer in Australia. A major cyclone formed in the Indian Ocean near the Pilbra coast, and clouds from it streamed along the graze path across Australia, a pattern that persisted for days. Perth with its Mediterrean climate was beautifully clear, but as we drove east, we ran into solid clouds near Southern Cross (where Dave Herald & I took pictures of each other on Antares Street). As we deployed at Bardoc, the sky was overcast except for a narrow strip of clear sky extending 10 degrees above the western horizon. This precluded any pre-pointing, but we observed the graze through a miraculous thinning of the clouds. Strong wind shaking spoiled the color recordings. I hoped for a better result that come this July 29 th. Reduction of the 2009 Feb. 17 graze by Mitsuru Sôma with Kaguya data. On 2016 Feb. we observed a graze near Bridgeton, WA, even farther from Green- belt, MD than Bardoc, but although it was farther from our permanent home, we were living in ACT, Australia, at the time. More will be in my talk on a half year downunder later today.

For the Aldebaran Graze, 2016 July 28/29 we travelled from Stillwater, OK to Carey, TX

Carey, TX (nw of Childress, where we met Ernie Iverson, stayed at his motel )

Pre-point chart for Mighty Mini’s by Ernie Since our motel’s printer was broken, I viewed the charts on Joan’s laptop

Our Sites were along (dirt) Road 7 s.e. of Carey, TX I paced stations from south (#1) to north (#18) across the “best” zone at 52-pace intervals (a little less than the star’s projected size) measured relative to telephone poles that show on Google Earth

Results at Rd. 7 near Carey, TX Potential Sites south (#1) to north (#18) In agreement with Ted Blank (US 177 sites), we covered mainly the northern half, while the US 177 observers would cover the southern half, with some overlap No significant wind, dry (no dew), clear view of the Moon At Station 9, I recorded with a color camera (PC33C) with a 5- in. SCT; battery contacts didn’t work, so undriven “Tuthill” equatorial mount with smooth manual motion in RA; using f/0.33 focal reducer gave wide FOV for few adjustments At Station 10, Joan used 80mm “midi” scope Prepointed Mighty Mini’s recorded at stations 7 and With many delays, ran out of time, so no data at sta