Mid-Atlantic (& Mid-West) Occultations, 2014 August - October David Dunham August 24 th (393) Lampetia occultation, Missouri Sept. 6 th (93) Minerva (& sat.) occultation, Minn. Sept. 12/13 th occ’n by Saturn’s Rhea, N.E. USA Upcoming occultations

A conference on planning for the 2017 August total solar eclipse, held on the 3 rd anti-anniversary of that event at the Univ. of Missouri in Columbia (near the central line of the 2017 eclipse), provided an excuse to try to observe this Sunday morning event from north-central Missouri. Also, we stayed with my brother-in-law, who works at the Univ. of Missouri. Occultations of faint stars by 49 Pales on Aug. 23 and by 39 Laetitia on Aug. 25 were also recorded from Columbia; Laetitia was positive; Pales star probably too faint for me.

With the 56  alt., I needed to make Ted Blank’s tensioner mod for the 4 120mm refractor “AZ4” mounts that I brought. Shorter dowels (white wooden cylinder; I spray- painted mine black) were used

Planned Remote Stations 1 – 3 north of Columbia The blue line is the predicted southern limit. My brother-in-law, Jim Bixby, helped me set up these three stations, and returned to them to attach and turn on the camcorders, and picked up the equipment afterwards. Joan tried to observe from Columbia.

Station 1 was most difficult, in high grass/bushes to hide the scope The poison ivy I got setting up the scope there is almost gone now.

Planned Remote Stations 4 – 6 farther north The green line is the predicted center, the blue line is the predicted northern limit, and the red line is the “1-  ” n. limit. I ran out of time and didn’t make it to the northernmost of these sites but had time to set up the 6 th site 2 miles south of the bottom one in Macon, MO.

So far, only Stations 5 & 6 near the central line have been analyzed There is an error in the times for chord 4 (my station 5) in this plot; chord 6 (my station 6; it was dry) is correct. With job obligations & the next 2 better events, I haven’t had time to work more on this. Dew compromised the sta. 5 maxi observation, and was also present in varying degrees at sta. 1 – 4. The mount failed at Columbia; when she got up to turn on the recorder there, the scope pointed straight up.

A conference on planning for the 2017 August total solar eclipse, held on the 3 rd anti-anniversary of that event at the Univ. of Missouri in Columbia (near the central line of the 2017 eclipse), provided an excuse to try to observe this Sunday morning event from north-central Missouri. Also, we stayed with my brother-in-law, who works at the Univ. of Missouri.

The target star was near 5 th -mag. 41 Tauri, and not far from the Pleiades.

6 Stations Planned, & Set Up, near I-94 from St. Cloud to Fergus Falls, MN Predicted lines are: Red, 1-  eastern limit; blue, eastern limit; & green, central line. In the lower left are two stations planned (and also successful) by Steve Messner from Northfied, MN (his sites were at/near a camp ground on SD border). Farther to the northwest, Paul Maley, with help from students at a local university, set up 4 stations around Fargo, ND to cover the western part of the path. Bob Sandy tried in Nebraska, but was clouded out.

All stations for the Minerva occultation; north is towards upper-upper-left Predicted lines are: Red, 1-  eastern limit; blue, eastern limit; & green, central line. Predicted lines: Green, center; Blue, limits; Red, 1-sigma limits. A good distribution, but the actual path shifted a little west. Red dots had no occultation; Green dots had an occultation.

A sky-plane plot showing the paths for all stations; our 3 eastern stations had no occultation (chords ). Joan assisted me all night. There is an error in the times for chord 4 (my station 5) in this plot; chord 6 (my station 6) is correct. With job obligations & the next 2 better events, I haven’t had time to work more on this.

The observations fit Minerva’s shape model very well.

Light Curve from Steve Messner’s campground remote station, closest to the predicted central line – “A lucky hit” The blue dots are for the taret star; the count at the bottom is in video frames (each 1/30 th sec.). The green line in the middle is a comparison star in the FOV that was not occulted. The thick red vertical lines mark the D and R by Minerva. But notice 20s after the main event, there is another brief drop lasting 0.6 seconds. This turned out to be an occultation by Minerva’s inner moon, Gorgoneion.

An expanded view showing the Gorgoneion event in the lower right.

This plot by Frédéric Vachier, IMCCE, Paris, shows that Steve Messner’s secondary occultation observation fits the orbit of Gorgoneion very well. The moon’s orbit is known, but not the position in the orbit, but IMCCE found that the new point is consistent with earlier observations. The position of the outer satellite Aegis is shown but its occultation was not observed. Messner’s chord is 6.5 km, larger than the expected 3.2 km size expected from the earlier data.

HIP = SAO

Expanded view showing States The predicted northern (red) and southern (blue) limits are highlighted. The sky was too bright to observe west of the Mississippi River.

Saturn was low in the southwest Saturn, Mars, and Antares, all orange and nearly the same brightness, were In a line at about the same altitude, with Saturn on the right.

The 7.8-mag. star was 1 arc minute east of Saturn, with Titan below it. Diagram adopted from skyandtelescope.com.

25h Transparency Forecast poor for MD; NJ looks best in Mid-Atlantic Region

13h Transparency Forecast better for MD, but NJ is farthest from the clouds So we went to NJ, and Ernie Iverson in TX looked at sat. images to try to guide us

IR satellite image close to the Rhea occultation time

Steve Conard got the best light curve with his C14 at Willow Oaks Obs. Diagram adopted from skyandtelescope.com. The Duration was 16.4s at Gamber, MD. At Greenbelt, MD, it was 9.3s, while at the US Naval Obs. in DC, it was 7.8s. Conard’s S/N was 7.0; the next best was 1.8. In NJ, I had 22.8s, S/N 0.8 through thin clouds. Duration almost 40s (actually, about 35s) at Westford, MA; central was 58s.

Sky-plane plot of the 2014 Sept. 12/13 Rhea observed chords The shortest chord, #9 at the US Naval Obs., was 7.8s; B. Huxtable in s. Del. had a close miss.

Upcoming Events for Central Maryland Asteroidal Occultations 2014 Satellite/ dur. Ap. Date Day EDT Star mag. Asteroid dmag s " Location Sep 18 Thu 20:34 4UC Chiron Cuba; e. USA? Sep 30 Tue 1:40 2UC Terpsichore w&nVA,DC,MD,ePA Sep 30 Tue 2:32 TYC Spiridonia OH,MD,NJ;DC,nVA? Oct 1 Wed 23:00 TYC C Laetitia All MidAt,not SC Oct 2 Thu 22:53 2UC Hera VA,DC,eMD,DE,sNJ _______________________________________________ Lunar Grazing Occultations 2014 Date Day EDT Star Mag % alt CA Location & Remarks Oct 1 Wed 21:21 SAO S *Hamltn,VA;MtAiry&Finksbrg,MD Oct 12 Sun 1:04 SAO N Chrltsv,Qantco,VA;Brndywin,MD Oct 14 Tue 6:42 ZC S Scotland,Loganville,PA;Sun -7 Interactive detailed maps at

Upcoming Events for Central Maryland Total Lunar Occultations 2014 Date Day EDT Ph Star Mag % alt CA Sp. Notes Oct 1 Wed 21:28 D SAO N B2 Mag2 8.7,sep. ".4,PA154 Oct 1 Wed 21:37 D ZC S A1 close dbl, mag2 7.8 Oct 1 Wed 21:44 D SAO S A2 Mg2 13, sep. 10",PA 150 Oct 4 Sat 1:04 D ZC S K4 Azimuth 239 deg. Oct 4 Sat 18:46 D ZC S K0 Sun alt. -1 deg. Oct 5 Sun 1:22 D ZC N K0 Oct 5 Sun 22:14 D LP Aqr N M0 close dbl,ZC3328,TmD 9" Oct 6 Mon 18:51 D 14 Psc S A2 Sun -3, Az. 102, ZC3474 Oct 11 Sat 23:38 R 63 Tauri S A1 ZC 650, Term. Dist. 9" Oct 13 Mon 5:29 R 115 Tauri S B5 ZC 814, close double Oct 13 Mon 6:53 R ZC N A2 Sun -5,Mag2 10,3",PA129 Oct 14 Tue 1:47 R ZC N A6 close equal dbl, "0.5 Oct 14 Tue 6:20 R ZC S G9 Sun alt. -12 deg. Explanations & more information is at David Dunham, phone