Spectacular Grazing Occultation Sat. pm, April 1, e. Iowa to Ocean City, MD
See 4th-mag. Maia flash on and off among mountains near the lunar north pole
This is the best grazing occultation in the DC region since 1969, easily visible with binoculars and some camcorders. The mile-wide graze path passes over Leesburg, VA; Potamac and Bethesda, MD; the northern corner of Washington, DC; and Takoma Park to southern Bowie, MD.
More observers will provide more detail of the lunar mountains, so we want as many as possible to join our effort to observe this. Even those with no previous astronomical experience can make valuable observations. Simple diagrams showing the Moon have been added.
Astro Meteo (Clear Sky Clock) predicts hazy but clear skies for the Maia graze in the Washington, DC region, but mostly cloudy elsewhere.
Updated: 2006 March 31
Early Saturday evening, April 1st, the thin crescent Moon, 16% sunlit, will be passing through the Pleiades (Seven Sisters) star cluster. It will be an interesting spectacle for anyone with binoculars to see. Some simple views of the event for the Washington, DC region are in this Power Point file showing the Moon as it will appear in the sky, in the proper orientation. With proper publicity, it can be used to generate interest in astronomy in our region. Anyone with a camcorder, or binoculars and a tape recorder, could even obtain scientifically useful recordings of the numerous occultations that will occur. Please spread the word to others about this interesting event visible across our area. I plan to write a "public" version, effectively a press release, of this but will not be able to post it here; if so, I'll send it to Derek Breit so that he can post it on his Web site. I have a few extra recorders that those who don't have any can borrow. Predictions of the total occultations of a few dozen stars brighter than 10th magnitude are at the bottom of my Mid-Atlantic occultations Web site. The Moon will take a few of hours to pass over the Pleiades, with the occultations occurring from when it starts to get dark at 6:30 pm until just before the Moon gets too low in the west at 10 pm. The occultations of the Pleiades stars can be seen from any convenient location in our region where it will be clear. But of special interest will be a grazing occultation of the 4th-magnitude star Maia, visible only from a mile-wide zone crossing the northern and eastern suburbs of Washington. In this narrow zone, the star will appear to move along a tangent line to the Moon's disk, and will flash on and off several times among the mountains and craters on the dark side of the Moon near the cusp at the Moon's north pole. Even casual observers won't want to miss this rare opportunity to see this dynamical display of celestial motion; it's the best graze in the Washington, DC region since 1969, easily visible with binoculars or any small telescope. If you are north of the graze zone, the Moon will narrowly miss the star and there will be no occultation. If you are south of it, the star will disappear on the dark side, then several minutes later will reappear on the bright side of the Moon. We plan to set up many observers at locations spread across the graze path. If each can time the series of disappearances and reappearances of the star at their location, a very detailed profile of the lunar topography near the north pole can be constructed. More observers will provide more detail of the lunar profile so we encourage as many people as possible to participate. You can get some idea of what a grazing occultation of a bright star looks like by looking at this video of the first part of a grazing occultation of Aldebaran recorded in Poland a few years ago. They also obtained a video of the exciting last part of the graze. The star remained hidden behind the Moon for about a minute between the two sequences. Simple methods for timing and/or video recording occultations are described here. For the Washington, DC region, if it is clear, I will be recording WTOP along with GPS & WWV time signals so that anyone else in the region can record WTOP at 1500 AM or 103.5 FM for an accurate time base. WEATHER The best weather for the Pleiades passage is expected to be in the southern Mid-Atlantic region, from southern Virginia to central South Carolina and westward to central Tennessee. The 36h forecast cloud cover maps for the start of the Pleiades passage (0h UT April 2 or 7 pm EST April 1) are below: eastern U.S.A. map is also in this Word file But after midnight tonight (after 5h UT April 1), you can get updated forecast maps at the Astro Meteo Web site. Based on the current forecast above, I plan to proceed with plans to observe the Maia graze from southern Bowie, described below. But if the new forecast shows that it will be much better for the Taygeta graze in Georgia (see the Taygeta page), I will consider going there, but that seems unlikely now. I won't be able to update this Web site after I write this, but more up-to-date information on plans will probably be on Derek Breit's Web page. The situation could change so that it might be worthwhile to go farther southeast along the path. THE GRAZE WEST OF THE DC AREA, OHIO TO WEST VIRGINIA Maia is 20 Tauri = ZC 541, a spectroscopic binary star that might be resolved during this graze. This is the brightest star grazed in the Mid-Atlantic region during this Pleiades passage, well worth a special effort to try to observe. Near Lima, Ohio, the Sun's altitude will be -7 deg.; although the twilight will be bright, in a telescope Maia will be easy to see then. Near Gambiers northeast of Columbus, OH, conditions will be good with the Sun alt. -9 deg.; Paula Turner at Kenyon College, turnerp@kenyon.edu, plans a small expedition of students to the graze path 3 miles south of Gambier. The graze zone offsets to use for that area of central Ohio on Charlie Ridgway's Web site are -0.8 km for the north edge and -2.8 km for the south edge of the zone. The skies will be even darker at Point Marion, PA, about 8 miles north of Morgantown, WV, where the Sun's altitude will be -11 deg. The path crosses I-81 at the VA/WV border between Winchester and Martinsburg, & over Charles Town, WV. Unfortunately, it looks like it will be mostly cloudy in all these areas, but maybe all right around Martinsburg, WV and eastward. THE GRAZE ACROSS THE WASHINGTON, DC REGION (Leesburg, VA to Bowie, MD) The graze path passes over parts of Leesburg, VA; Potomac and Bethesda, MD; the northern District; and Takoma Park to southern Bowie, MD. Maps below show the graze zone between the two gray lines; ignore the yellow reference line (the predicted lunar profile shows that only a close miss will occur there). Perhaps the best place for an expedition will be in southern Bowie, along Jennings Mill Drive just south of Route 214 (Central Ave.). I've observed a couple of previous grazes in that suburban area with good results. Observers planning to observe the Maia graze with my expedition should either bring a picnic dinner, or eat early before the graze, or late afterwards; some of us might go to a nearby restaurant. For my expedition, meet by 7:00 pm (earlier if possible) at the intersection of Jones Bridge Rd. and Jennings Mill Dr. in south Bowie; these maps show the location. When you arrive at your observing location, inform the nearest resident of your plans and respect their wishes of where to park; I will try to have some handouts giving a basic explanation of this "rare eclipse of a bright star by the edge of the Moon visible only in this area". Invite them to see the Moon in your telescope or video monitor, perhaps after the graze if you are short on time to set up. Earlier, we looked at the possibility of possibly using the large parking area of Six Flags Amusement Park, which covers much but not all of the graze zone, but so far I have not heard if this will be possible. The Maia graze expedition can be an exciting alternative to the star parties that would normally be held the first Saturday evening of April; we can have a very interesting star party in the graze zone. The graze will occur from 7:42 to 7:46 pm EST. That's certainly the main show, but for those interested in watching the many total occultations of Pleiades stars, they will be visible starting when it gets dark enough about 6:30 pm until the Moon gets too low around 10 pm. Details of our expedition, with suggested meeting times and locations, will be posted here as soon as they are determined. Vince Sempronio writes: "I plan to observe in Ayrlawn Park in Bethesda. It is at the end of Oakmont Ave off of Old Georgetown Rd. The park is about a 1/4 mile south of the north gray line on David's map. There is another park (Hillmead Park) near the southern limit in Bethesda as well. it is off of Bradley Blvd. near the Landon school. The Ayrlawn Park is about 1000 ft across (perpendicular to the graze path) and should have enough space to handle one other observer. If anyone is interested in joining up with me there, I can lend them a KIWI-OSD video time inserter and possibly a spare video camera. email me at vinenator@pfdsystems.com if you are interested." A detailed map of this area is below. The aerial view shows a lot of trees at Hillmead Park, so I don't know how it will work. The fields at the Bradley Hills Elementary School, in the middle of the graze zone beside Hempstead Ave., I think will provide better sites. Vince Sempronio's cell phone is 301-518-4326. Chuck Quintero (cell 301-356-7019) and Don Gardner (cell 410-733-4399) plan to observe from the parking lot of Kingsford Elementary School just east of MD Route 193 near Woodmore, between the Beltway and southern Bowie. This map shows the school just south of center; the gray lines are NOT the graze zone, but are at distances of -1.38 and -1.5 km s. of the northern limit line, marking opposite corners of the school's parking lot. There may be other expeditions at other locations along the path; let me know at dunham@starpower.net and I will try to post information here and/or distribute it by e-mail. But I will not be able to update this Web site from March 24 to March 30 when I'll be travelling to Turkey for the March 29th total solar eclipse; if you copy information to Derek Breit at breit_ideas@hotmail.com , he can probably post it on his Web site. Those who live in the path could simply observe from home, or a nearby convenient location with a good view to the west. At the time of the graze, the Moon will be over 30 degrees high in the west, but it will sink lower for some of the other bright total occultations later during the Pleiades passage. Below are links to several static maps showing the graze path, first some overviews, then more detailed views across the Washington, DC region from west to east. Below them I give links to Charlie Ridgway's interactive Web site where you can obtain your own even more detailed views for any area along the path. Remember that the graze multiple events zone is between the two gray lines on the maps. The whole path, east Iowa to Ocean City, MD Overview, Washington, DC region northern Virginia, Leesburg & west of there Potomac River, west of Washington, DC Potomac and Bethesda, MD north DC, & Chevy Chase & Takoma Park, MD w. Prince Georges County, MD, Takoma Park to Beltway central Prince Georges County, MD, Beltway to s. Bowie s. Bowie to Chesapeake Bay, MD Detailed view of the path in central Bethesda, Maryland central Bethesda, MD (map) MD 191 = Bradley Blvd. Word version of the above Detailed views of the path in central Prince Georges County, Maryland southern Bowie, MD (map) southern Bowie, MD (aerial view) Central Ave./Six Flags area, MD (map) Central Ave./Six Flags area, MD (aerial view) All of the maps above are in this 17-megabyte Word file. This notice, with just the DC overview and central PG County maps, are in this 3-megabyte Word file. Just in case, I add some maps of the path over the Eastern Shore below. Path over Eastern Shore, MD Detailed view s. of Easton, MD Unfortunately, I didn't save separately a map of the path over Tilghman Island, but it is in the Word file below. Path over Ocean City, MD But the path is not shown, just its area. All of the above are in this Word file with some descriptive notes. Charlie Ridgway has posted path overlays on interactive maps that use google maps to give very detailed map and aerial vies of graze zones as well as of asteroidal occultations. His general Web site has links to the map sites and describes how to "navigate" the maps to get very detailed views of regions of interest. There is a link specifically for the 2006 Pleiades grazes; scroll down to April for the April 1/2 Pleiades passage. The link for the Maia graze is here. I have used this site to produce the maps shown above. A link to a Power Point file showing the Moon in the Pleiades is near the top of this page. Some other more basic views (.gif files) are below, mainly for anyone who might want to try to make other graphics of this rare event. Path of the Moon through the Pleiades for the Washington, DC area, with proper orientation, up towards the zenith. Bare Moon, unshaded, lunar north is up. Shaded Moon with up towards the zenith. David Dunham e-mail: home, dunham@starpower.net office, david.dunham@jhuapl.edu phones cell 301-526-5590; office 240-228-5609; home 301-474-4722