[Asteroidal Occultation] Observational Results from 2012

(actually, since 2011 July 18)

2012 October 19

IOTA meeting, Las Vegas, Nevada

David W. Dunham

Occultation of LQ Aquarii on 2011 July 19

mapped the profileof the binary asteroid (90) Antiope

David W. Dunham,

International Occultation Timing Association

and KinetX, and many others, from IOTA,

IMCCE (Paris Observatory), the SETI Institute,

Southwest Research Institute, JPL, Sierra College,

etc.

Predicted Path of theOccultation of the6.7-mag. Star by(90) Antiope

The path over northern Calif. & Nevada

IOTA meeting at Sierra College, Rocklin, CA

One of the pre-point charts prepared for the 50mm binocular lens-based “mighty mini” systems

LQ

70

Hydor

tau

69

74

sigma

54psi

phi

chi

Situla

MOON

rho Ancha

Skat77

37KR

36

iota

66

68

58

94

97

Pre-point line of

declination (UT)

5Circle

Setting up a mighty mini at my station #5 in Newman, Calif.

Light curve of the occultation atDunham Station #1 west of Tracy, Calif.

The angular diameter of the red giant star caused the disappearance andreappearance to be gradual over several tenths of a second, with differentdurations at the two events due to different slopes of the asteroid’s surface

Preliminary Sky-plane Profile

Occultation of 8.9-mag. SAO 95144 by (360) Carlova in Carolinas Aug. 15

• Bill Keel recorded a central occultation, 3.3s long, at Univ. of AL, Tuscaloosa

• He was near the northern limit, showing that the path shifted ½ path-width north

• Scotty Degenhardt ran 7 stations, mostly in the s. part of the path in s.e. AL

• His 2 northern stations, n. of center, had short occultations; the others had misses

David Dunham’s stations for the Carlova occ’n

The scope symbols show some of the stations that I planned to set up, but it was very cloudy along I-26 . When I reached Spartanburg, SC, I decided to go west on I-85, and found clear sky at Greenville. From there, I deployed 5 stations south near US25, shown by green dots.

My stations bracketing the predicted n. limit (the blue line) all were in the actual occultation path. In addition, I ran a 6th station much farther north, at a friend’s place in Hendersonville, NC, but unfortunately the digital recorder there did not write to the SD card correctly, only junk.

All stations for the Carlova occ’n

Carlova Occultation profile with best-fit ellipse

Carlova Shape Model Fit

Occult Watcher Ginevra Plan

To Oklahoma for Ginevra

Lavonne Occult profileObserversOf the GinevraOccultation,Sept. 27, 2011

Arachne OW stations 3-9

3

9

ErnieIverson’sLine(cloudy)

Arachne OW stations 1 & 2 (cloudy)

2

1

Not used

Arachne Sta. 3, Foster Cemetery

Sky-Plane Plot

Limovie Lightcurve for my Station #3at Foster Cemetery, e. of Huntsville, TX

Analyzed by Scotty Degenhardt

Occultation of SAO 60804, mag. 8.0, by the Trojan Asteroid

(911) Agamemnon Thurs. morning, 2012 January 19

This is the best, most valuable asteroidal occultation over the MD/greater Washington, DC region this year

We need your help to observe it

Following are maps of the path, and several star charts to locate the star in obscure Lynx;

Pre-pointing may be needed by most to find the star

= SAO 138052,spec. type K0

In coastal Mid-Atlanticregion (DC, Philadel-

phia, Richmond, etc.),Star alt. 24 in az. 299(northwest, opposite

Sun, whose alt. will be -10)

Occultation in Mid-Atlanticregion at 11:31:40 UT 11s(6:31am & 40s EST)

View of the Earthas seen from

(911) Agamemnon

Finder chart, 2 on a side

Map of 2012 Jan. 19th Agamemnon occ’n observers

Dunham-4 Dunham-3

Dunham-1

Conard

Tolea Brooks

Green dots mark positive observations, while red (Brooks) indicates a miss (negative, no occ’n).The green line is the predicted central line while the blue lines are the predicted path limits.The gray lines mark a 10-km zone bracketing Conard’s location where the satellite occ’n occurred.

Dunhamran a 2nd

station between#1 and #3but the videorecorderat #2failed.

Steve Conard’s light curve of the Jan. 19th Agamemnon occultation

Sky-plane plot, 2012 Jan. 19th (911) Agamemnon occultation

23

6

4

8

9

100 km

Satellite

Agamemnon: Axes 190.6 0.9 by 143.8 1.5 km, PA minor axis -69.3 1.3, center X 4661.6 0.4 km, Y 3113.7 0.6 km; disappearances on right sideSatellite plotted as 9-km circle (but it’s more likely about 4 km across) 0.0931 (278 km in the plane) from Agamemnon’s center in PA 93.8

Occ’n of BN Orionis by (57) Melpomene, 2012 March 11, path

Occ’n of BN Orionis by (57) Melpomene, 2012 March 11, stations

Occ’n of BN Orionis by (57) Melpomene, 2012 March 11