Small cusp-angle graze of omega2 Tauri recorded with 80mm remote systems in Minnesota on 2012 August 11 - New 2012 September 13
I attended an astrodynamics conference in Minneapolis Aug. 12-16. I went there early because I notced that this rather bright graze occurred there early the weekend before the conference. With the small cusp angle, 2N, I thought that there would be too much glare to record with my 80mm short-tube refractor "midi" video systems, but I took 2 of them, to try, and 2 10cm SCT's for more magnification at attended stations that Joan and I ran. But like in Arizona for the eta Gem graze in April 2011, the machines triumphed; it was machines, 2; humans, 0. Maybe a few events were lost while the star was at the northern cusp at the start of the graze, but the star was easily recorded during most of the graze with the "midi" systems. At one station, 6 disappearances and 6 reappearanes were recorded, while at the southernmost station, only 4 events were recorded, 3 of them very close to the cusp. The observations indicated a south shift of about 150m relative to the Kaguya lunar profile. The star is ZC 628, a spectral type A3 star about 93 light-years away. The 35% sunlit waning crescent Moon was 22 deg. above the eastern horizon; the graze took place at 3:44am CDT (8:44 UT) Saturday morning, August 11. Brad Timerson has placed the recording made at the northern remote station on YouTube; visit his occultation videos web page and click on the item on the first line for the 2012 August 11th graze. Or you can go directly to the YouTube web page. This map of the Minneapolis-St. Paul area shows the graze zone, between the two dark gray lines that define the graze zone for this shallow area of the Moon (the green line is the predicted northern limit line assuming a spherical Moon with its mean radius, but since the event occurred in a low area, only a close miss, with no occultation, occurred at the green line). The observation sites were just south of the small town of Grant, whose name is underlined northeast of St. Paul on the map. The path is shown in more detail on this map of the Grant, MN area. Here is an areal view; the sites were all close to Jamaca Ave N. The sites were along Jamaca Ave. N, just south of the northern dark gray line, except for the southern remote station, which was placed in some bushes in the median of Jeffrey Blvd N about 200m northeast of its intersection with Jamaca Ave. N. Jeffrey Blvd N is not named in the view, but it is the road that extends northeast from the point where the southern dark gray line crosses Jamaca Ave. N. The northern three stations were all located in the area shown on this detailed aerial view. The northern remote video station was near the "8472" at the bottom of the figure. The attended stations were farther north, within the dark gray lines that define a narrow (200m wide) zone where the Kaguya predicted profile indicated that the most action would take place. Note the "N" in "Jamaca Ave N"; that is near where this image was taken, a panoramic Streetview looking southwest. The northern remote station was placed on the west shoulder of Jamaca Ave. beyond the nearest car, but far enough north so that the trees on the east side of the road didn't block the view of the Moon rising in the east. Robert Bateman from the Minnesota Astronomical Society (MAS) joined us, but he only brought a pair of binoculars that were insufficient to see the graze. He parked his car near the northern remote station, effectively protecting it, but at that time of night, there were few vehicles on the road. Other MAS members Lorin Nelson and Ivan Policoff also observed the graze, from locations near their homes. _____________________________ David Dunham, 2012 September 13 Phones home 301-220-0415; office 240-228-5609; cell 301-526-5590 office e-mail david.dunham@kinetx.com Moscow cell 011-7-916-0929487 home e-mail: dunham@starpower.net .