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 .