Mid-Atlantic Occultations to mid October 2012 - Updated 2012 August 31
Good Mnemosyne asteroidal occultation across DC region observed March 10th pm
The star, BN Orionis, a variable Halpha emission star, was found to be a close binary
Small cusp-angle graze of omega2 Tauri recorded with 80mm remote systems in Minnesota
For non-astronomers, "occultation" is a term that astronomers use for an eclipse of a star by an asteroid or by the Moon. Click here, and then click on "Video" on the Jan. 19th line, to see Steve's spectacular video of the Agamemnon occultations. _______________________________________________ Mid-Atlantic Planetary & Asteroidal Occultations to mid October 2012 2012 EST/ dur. Ap. Date Day EDT Star Mag. Asteroid dmag s " Location Jan 19 Thu 6:31 SAO 60804 8.0 Agamemnon 6.8 9 2 DE,MD,DC,nVA,PA Mar 10 Sat 23:20 BN Orionis 9.7 Mnemosyne 2.8 7 4 WV,nVA,DC,sMD,DE *** Dates and times above are EST, those below are EDT *** May 11 Fri 23:45 SAO 140947 6.5 Bellona 4.7 11 2 s Khabarovsk, RU Sep 9 Sun 20:43 SAO 187062 9.9 Utra 6.2 3 4 seSC,eNC,seVA Sep 10 Mon 20:57 2UC32969917 11.6 2007 OC10 9.6 12 7 TNO;S.Amr.;eUSA? Sep 19 Wed 21:56 SAO 187032 9.4 1993 NB 6.7 1 4 PA,NJ;MD,DC,DE? Sep 20 Thu 3:15 SAO 164891 8.0 2000 PD30 15.8 6 2 TNO;S.Amer.;USA? Oct 8 Mon 6:42 2UC40000398 10.9 Metis 0.5 12 6 MD,DC,nVA;Sun -6 Oct 13 Sat 3:45 SAO 94922 8.1 Kani 8.3 3 2 nGA,SC,sNC We now have "final" astrometric updates for the events listed above through July 18. Stars with designations starting "2UC" are UCAC2 stars; their magnitudes are not as accurate as the other catalogs so they might be half a magnitude or more fainter than the listed mag.; if near the limit of your telescope, checking the star's some night before the event is recommended. Observers should watch these from convenient home or near-home locations without making a significant mobile effort, except for some of the better events mentioned below, where the chances for an occultation warrant an expedition from the DC region, weather permitting. A "C" following the star's magnitude means that the mag. given is not the star's magnitude, but is the combined mag. of the star and the asteroid; add the dmag to it for the mag. of the asteroid (which is what you will see in case of an occultation). Standard 2-letter designations are used for States and Canadian provinces, and for some countries. I use NE for New England, LI for Long Island (NY), CC for Cape Cod (MA), and c for central. Either use Occult Watcher, or find the event on Steve Preston's Web site to see a map of the map, where you can see which States and Canadian provinces are in or near the path. Unless the star is relatively bright, I've eliminated events with distances greater than 650 km (expeditions are possible to outside the Mid- Atlantic region for bright stars involving reasonably large asteroids). But it is necessary to look at a map to be sure that an event might be visible from the Mid-Atlantic region (which I define as including OH, PA, and NJ south to SC, but I generally exclude faint events in SC. If you live within the predicted paths for any of the above events, or within the 2-sigma uncertainty limits, please try to observe them from convenient home locations. In addition, you may want to help, or join, a possible expedition from the DC area that may be undertaken, weather permitting, for the event on Mar. 10. Many will probably not be attempted due to forecasts of cloudy weather. I usually give the wider paths with better statistics priority. Details of observations of previous events, have been, or soon will be, posted on Brad Timerson's North American asteroidal occultation results page. I only list above, and give some information below, about events that have not been analyzed (some of the tapes not reviewed carefully) or that have been observed recently. More information about the asteroidal occultations listed above are in this Power Point file. Some additional information is given on the North American asteroidal occultation results page with link given above. Jan. 19, Agamemnon: This rank 93 event was important since (911) Agememnon is one of the larger Jupiter Trojan asteroids, perhaps the most important in the DC area this year. The star is HIP 41337, spectral type K0. Click here for much more about this valuable occultation (prediction information). A small south shift occurred, as shown by Steve Conard's nearly central event at his Willow Oaks Observatory in Gamber, MD, west of Baltimore; click here for more information and graphics of this occultation, showing Steve Conard's observations that show that Agamemnon probably has a small satellite. It includes a link to a YouTube page that shows Steve's remarkable video recording. Alin Tolea recorded the occultation with a mighty mini from Silver Spring, MD, and I recorded the occultation from three other sites, also using mighty mini's, in the northern part of the path on the Delmarva Peninsula. Mar. 10: The star is SAO 112952 = TYC 0126-00781-1, spectral type A7. This relatively bright rank 95 event was one of the better occultations predicted for the Washington, DC region this year. It occurred during the night of the meeting of the National Capital Astronomers, about 90 minutes after the meeting normally ends, allowing time to return home and set up to try to observe the occultation. Wayne Warren did that, working with Joan at our home in Greenbelt, MD to video record an approximately 5s occultation with an 80mm "midi" system. Farther north, Steve Conard recorded a miss at his home Willow Oaks Observatory, run as a remote station, then drove south to Dayton, MD where he recorded a short 1.5s event, showing that the path shifted about 35 km north of the nominal predicction, a little larger than the north shift predicted by the PPMXL catalog. Farther south, I set up all 5 of my other midi's run as remote stations and a 120mm "maxi" at my last attended station s. of Doswell, VA. The video recorder failed at the northernmost station at the Presidential Golf Course in Upper Marlboro, MD, but the others all worked, with the station at Hawthorne Country Club, MD recording a nice 7.7s occultation. The next station, at Port Conway, VA apparently had a miss, analysis showed that some flickering near the expected time is likely atmospheric; in any case, that station must have been close to the actual s. limit; it was 30 km n. of the nominal predicted s. limit. Other midis at Bowling Green and n. Doswell had no occultation. My attended station was set up only about 15 min. after setting up my last remote station; it was at an intersection only about 2 km farther south. A policeman showed up 2 min. before the occultation, and fortunately was accommodating, turning off his headlights during the crtical minute. May 11: The star is HIP 78870, spectral type K0. With help from local amateur astronomers, six "mighty mini" systems were deployed across the predicted path north and south of Khabarovsk, in the Russian Far East (north of Vladivostok), with some success. An account of the effort is in this Word file, with a google translation of it into Russian here. Sept. 9, the star is TYC 6870-00570-1, spectral type K0. (1447) Utra is expected to be 12 km across, with an occultation rank of only 13. Sept. 19, the star is TYC 6858-01080-1, spectral type B9. (14465) 1993 NB is only about 11 km across, giving a rank of only 13. Sept. 20, the star is HIP 109357, spectral type K0. Oct. 13, the star is TYC 1303-0094-1, spectral type F8. With a diameter of about 18 km and rank 26, it's not worth an expedition from the DC area, but observers in the Carolinas are encouraged to observe from convenient home locations. For these asteroidal occultations, see the path maps, detailed finder charts, and other info. at Steve Preston's Web site. Very detailed maps for most of these are on Derek Breit's interactive Web page that links to the very detailed maps and satellite imagery of maps.google.com with overlays of the occultation paths (in the google maps column). Also on Breit's Web site are station lists giving local circumstances, for many observer stations. It gives the predicted time of the event, distance from the updated central line, probability that an occultation will occur there, and altitudes of the star and the Sun. If your station is not in that list, please let me and Derek, firstname.lastname@example.org , know so that you can be added to future lists. There is also a column that has a list of stars with declinations similar to that of the target star, with offset times and declination differences, that can be used to pre-point a telescope to where the target star will be at the time of the occultation. There are at least a few bright stars that can be used to pre-point your telescope during the few hours before the event so that you don't have to try to find faint target stars directly. Events not on the above Web sites, generally for the fainter stars, are on Steve Messner's Web site. I recommend installing new software called Occult Watcher, where you input your position and it searches Steve Preston's predition Web site, informing you of all asteroidal occultations in your region during the next 4-5 weeks, giving probabilities and other details. Whenever a path is updated, the software lets you know. It also has provision for you to specify your observing intentions, and these are displayed along with those of other observers to help plan the overall coverage for the event. Hristo Pavlov in Sydney, Australia wrote this program; you can get it here. Much more information about asteroidal occultations in general is here. Please go to that link to get information for your site and help us measure the sizes and shapes of these asteroids. For reporting observations, even if the star is monitored and no occultation is seen, you should use the new report forms that you can get here and click on "Templates for Report Forms". Completed reports should be sent to email@example.com . Brad Timerson has created a comprehensive site about asteroidal occultations, including links to most other known Web sites worldwide with useful information (predictions and observations) about these events, here. He also collects, analyzes, and posts reports of, observations of these events observed in North America. ________ Lunar Grazing Occultations through mid October 2012 You can zoom in on some of these paths using Brad Timerson's interactive Google maps Web site. But you need to know the offsets for the graze zone in your area; we can help you determine that. Brad can usually add events not on his Web site by request to him at firstname.lastname@example.org . 2012 Date Day EDT Star Mag % alt CA Location, Notes Aug 11 Sat 3:44 omega2 Tau 4.9 35- 22 2N Grant, Minnesota Sep 7 Fri 4:54 ZC 595 6.8 61- 64 1N *Dayton, Ohio; nw PA; se NY Sep 9 Sun 5:44 SAO 77515 8.2 42- 60 1S *Skiprs,Sufolk,&Chesapeak,VA Sep 13 Thu 6:15 ZC 1372 7.8 8- 23 8S *Chrltsvil&Ladysmith,VASun -8 Sep 19 Wed 20:03 ZC 2156 7.7 19+ 11 10S *Barborsv,Occoqn,VA;Waldrf,MD Oct 6 Sat 1:20 SAO 77118 7.7 69- 34 4N *Winchester,VA&Westminster,MD Oct 9 Tue 4:50 SAO 97442 8.0 39- 43 3S *Rockville,Laurel,SevernaP,MD Oct 10 Wed 3:12 ZC 1318 5.9 30- 14 1S *nPA, Springfield & Boston,MA Oct 10 Wed 3:49 ZC 1320 6.7 30- 21 0N *Pittsburgh ¢ral PA; n.NJ Oct 10 Wed 4:54 SAO 98152 9.0 29- 33 4S *Harrisburg & Philadelphia,PA Oct 11 Thu 6:52 SAO 117875 8.8 20- 42 4S *Medina&Yungstn,OH;Indiana,PA Oct 12 Fri 6:05 SAO 118363 9.1 12- 23 8S *Falmouth, VA; Nanjemoy, MD Notes: Some grazes will not be attempted if expeditions are undertaken for asteroidal occultations within 36 hours of the graze. * in the Notes column means that no DC-area expedition is planned. Under Location, if two numbers are given, the first is the distance of the northern (for cusp angles, or CA, with N) or southern (for CA with S) limit (the graze line) from Greenbelt, MD and the second number is the bearing (azimuth) of that distance in deg. For example, a bearing of 0 means that it is a west-to-east path passing north of Greenbelt, 345 would indicate a wsw-to-ene path whose closest point would be nnw of Greenbelt, and 205 would indicate a wnw-to-ese path whose closest point would be ssw of Greenbelt. Geographical locations of the path can be estimated from the stations with small distances in the observer scans that are given in the text (.txt) file of limit predictions (provided to IOTA members for grazes within their travel radius) for the event, or they can be more accurately estimated by using the Google map for the event on Brad Timerson's Web site given in the heading above. A letter preceding the distance is the star's double star code from the XZ80Q catalog; information about the duplicity is given in the text file for the event. Aug. 11: 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, 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. _______________________________________________ Total Lunar Occultations The better total lunar occultations through mid October 2012 visible from throughout the Washington-Baltimore greater metropolitan area are listed below. Some can be accurately timed by aiming a camcorder into a low-power eyepiece of your telescope and recording WWV with the audio. These predictions are for Greenbelt, MD. IOTA members were sent predictions for their location, generally accurate to a couple of seconds, at the beginning of the year. I also computed predictions for a few hundred other observers, likely for you or for a location near you, and will provide an appropriate .zip file upon request. You can also download IOTA's Occult 4 program at no cost here and compute your own predictions. That has the advantage that you can use it to create views of the Moon showing the locations of each reappearing star in the predictions that you generate. 2012 Date Day EDT Ph Star Mag % alt CA Sp. Notes Aug 31 Fri 21:31 R ZC 3370 6.2 100- 23 81S G8 AA 228,TmD7",close dbl? Sep 2 Sun 0:44 R 22 Piscium 5.6 97- 49 24S K4 AA194,ZC3512,Term.D. 9" Sep 5 Wed 5:34 R SAO 92900 7.9 78- 63 60S A0 spectroscopic binary Sep 6 Thu 2:53 R UW Arietis 6.1 71- 53 75S B1 ZC 455, close double? Sep 7 Fri 5:16 R ZC 595 6.8 61- 69 35N K1 Close double? Sep 7 Fri 5:59 R SAO 93729 8.0 61- 71 66S A2 Sun altitude -9 degrees Sep 9 Sun 1:28 R SAO 77323 7.7 43- 12 56N G4 Azimuth 73 degrees Sep 9 Sun 4:07 R Ceres 8.8 42- 42 17S pred. dur. 1.8 sec. Sep 9 Sun 4:22 R SAO 77433 7.9 42- 45 70S A0 Sep 9 Sun 5:44 R SAO 77493 8.2 42- 60 44S B9 Sep 9 Sun 6:09 R SAO 77515 8.2 42- 64 32S K0 Sun altitude -7 degrees Sep 9 Sun 6:35 R Y Tauri 6.9 41- 67 85S M5 Sun -2,SAO 77516,min. 9 Sep 10 Mon 3:10 R SAO 95790 7.9 33- 22 68N G5 Sep 10 Mon 3:32 R SAO 95822 8.0 33- 26 28N B8 Sep 10 Mon 4:26 R 22 Gem 7.1 33- 36 42S A0 ZC 1006, spec. binary Sep 10 Mon 5:31 R SAO 95890 8.2 32- 48 80S A0 Sep 10 Mon 6:36 R SAO 95919 8.4 32- 59 59S K0 Sun -2,mg2 13 5",PA 9dg Sep 11 Tue 2:43 R ZC 1116 7.2 24- 6 27S B9 Azimuth 73 deg. Sep 11 Tue 6:33 R SAO 96950 8.4 23- 49 77S A2 Sun alt. -3 deg. Sep 13 Thu 6:21 R SAO 98437 8.1 8- 24 67N F5 Sun -6,mg2 12,1.8",PA57 Sep 13 Thu 6:27 R ZC 1372 7.8 8- 25 27S K0 Sun alt. -5 deg. Sep 19 Wed 19:57 D ZC 2156 7.7 19+ 12 19S K0 Sun alt.-10, Az. 232 Sep 20 Thu 19:47 D SAO 184141 8.0 29+ 20 50S G3 Sun -9, close double Sep 20 Thu 19:49 D SAO 184137 7.9 29+ 20 8N G5 Sun altitude -9 degrees Sep 21 Fri 21:44 D ZC 2472 7.0 41+ 12 9N F2 Azimuth 229 degrees Sep 22 Sat 21:33 D mu Sgr 3.8 52+ 22 61N B2 ZC 2633; close double?? Sep 22 Sat 22:27 D SAO 186535 7.9 53+ 15 33N K0 Azimuth 226 deg. Sep 23 Sun 19:03 D ZC 2791 5.6 63+ 30 35N B2 Sun -1, spect. binary Sep 23 Sun 19:29 D SAO 162253 8.2 63+ 31 80N A0 Sun altitude -6 deg. Sep 23 Sun 20:59 D SAO 162295 8.2 63+ 31 65N G3 Sep 23 Sun 21:30 D SAO 162311 8.1 63+ 29 90S G0 Sep 24 Mon 0:19 D 43 Sgr 4.9 64+ 8 60S K0 Az237,ZC2814,close dbl? Sep 24 Mon 19:14 D SAO 163249 7.6 73+ 30 50N K5 Sun alt. -4 deg. Sep 25 Tue 21:12 D SAO 164080 7.1 83+ 38 83N K4 maybe a close double Sep 26 Wed 2:13 D nu Aquarii 4.5 84+ 12 46N G8 Az. 245, ZC 3093 Sep 27 Thu 20:42 D SAO 146252 7.2 95+ 34 36N A0 Sep 29 Sat 1:27 D 16 Piscium 5.7 99+ 49 16N F6 ZC3482,dbl,Term Dist 1" Sep 30 Sun 23:18 R ZC 166 6.7 99- 48 84S M* AA 253, Term.Dist. 19" Oct 1 Mon 1:40 R ZC 173 6.5 99- 62 77S G5 AA 246 Oct 3 Wed 23:31 R ZC 519 7.6 85- 31 60N K5 Oct 5 Fri 7:45 R HU Tauri 5.9 76- 48 32N B8 Sun+6, ZC 700,spec.bin. Oct 6 Sat 1:28 R SAO 77118 7.7 69- 36 18N A0 Oct 6 Sat 4:52 R ZC 808 6.8 68- 70 67S B0 Oct 7 Sun 1:53 R 68 Orionis 5.8 60- 31 49S B9 ZC 940, close double? Oct 8 Mon 2:18 R SAO 96427 8.3 50- 26 87N K0 maybe close double Oct 8 Mon 5:26 R SAO 96538 7.4 49- 60 69N K0 Oct 8 Mon 5:57 R SAO 96564 8.3 49- 64 55S A0 Oct 8 Mon 6:20 R SAO 96573 8.2 49- 67 72N Sun -11, close double? Oct 9 Tue 2:02 R ZC 1190 7.2 40- 12 47N A2 Azimuth 79; see note Oct 9 Tue 3:50 R 1 Cancri 5.8 40- 33 80N K3 ZC 1197 Oct 10 Wed 4:02 R FX Cancri 6.7 30- 24 25N M3 ZC 1320 Oct 10 Wed 5:02 R SAO 98146 7.7 29- 35 76S F5 maybe close double Oct 10 Wed 6:12 R SAO 98174 8.2 29- 47 80N F0 closeDbl &mg12,15",PA98 Oct 10 Wed 6:27 R SAO 98178 7.8 29- 50 56S K0 Sun -9, close double? Oct 11 Thu 4:50 R SAO 117836 7.2 20- 21 59N G5 Oct 11 Thu 6:56 R SAO 117874 8.0 20- 44 53N G0 Sun alt. -4 deg. Oct 13 Sat 6:50 R ZC 1662 6.4 6- 19 25N K2 Sun -6,mg2 8, sep. 0.2" Notes Oct. 9, ZC 1190, the star has an 11th-mag. companion 16" away in PA 20, but the primary star may also be a close double D following the time denotes a disappearance, while R indicates that the event is a reappearance. When a power (x; actually, zoom factor) is given in the Notes, the event can probably be recorded directly with a camcorder of that power with no telescope needed. The times are for Greenbelt, MD, and will be good to within +/-1 min. for other locations in the Washington-Baltimore metropolitan areas unless the cusp angle (CA) is less than 30 deg., in which case, it might be as much as 5 minutes different for other locations across the region. Some stars in Flamsteed's catalog are in the wrong constellation, according to the official IAU constellation boundaries that were established well after Flamsteed's catalog was published. In these cases, Flamsteed's constellation is in parentheses and the actual constellation is given in the notes following a /. Mag is the star's magnitude. % is the percent of the Moon's visible disk that is sunlit, followed by a + indicating that the Moon is waxing and - showing that it is waning. So 0 is new moon, 50+ is first quarter, 100+ or - is full moon, and 50- is last quarter. The Moon is crescent if % is less than 50 and is gibbous if it is more than 50. Cusp Angle is described more fully at the main IOTA Web site - see above. Sp. is the star's spectral type (color), O,B,blue; A,F,white; G,yellow; K,orange; M,N,S,C red. Also in the notes, information about double stars is often given. "Close double" with no other information usually means nearly equal components with a separation less than 0.2". "mg2" or "m2" means the magnitude of the secondary component, followed by its separation in arc seconds ("), and sometimes its PA from the primary. If there is a 3rd component (for a triple star), it might be indicated with "mg3" or "m3". Double is sometime abbreviated "dbl". Sometimes the axis angle (AA) is given; it is aligned with the Moon's rotation axis and can be used to estimate where a star will reappear relative to lunar features. The selenographic latitude is AA -270. For example, AA 305 - 310 is near Mare Crisium. Many more total occultations will be visible with 5" and larger telescopes than are listed here. If you want to try to observe some of these events, it is better to use predictions computed for your location, such as those given in the IOTA annual predictions that have been distributed to IOTA members, and are available to others upon request. ________________________________________________________ Timing equipment and even telescopes can be loaned for most expeditions that we actually undertake; we are always shortest of observers who can fit these events in their schedule, so we hope that you might be able to. Information on timing occultations is . Good luck with your observations. Techniques for timing occultations using whatever resources that you may have are described here. Much information about observing occultations of all types is in "Chasing the Shadow: The IOTA Occultation Observer's Manual" available for free download here. _____________________________ David Dunham, 2012 August 31 Phones home 301-220-0415; office 240-228-5609; cell 301-526-5590 office e-mail email@example.com Moscow cell 011-7-916-0929487 home e-mail: firstname.lastname@example.org .