Naked-eye Regulus graze in S. Carolina Tues. pm June 19
The graze can be seen with telescopes in daylight, Winnipeg to
Louisville
Total occultation visible throughout w. & s. N. America, the
Caribbean, and n.w. S. America
New: 2007 June 18, 21h UT
You have a chance to see 1.4-mag. Regulus (ZC 1487) flash off and on
repeatedly among mountains and craters near the north pole on the
dark side of the 26% sunlit Moon between 0:31 and 1:26 UT June 20th
(actually early Tues. pm, June 19, 7:31-8:12 pm CDT from Kentucky to
Manitoba or 9:12-9:26 pm EDT from S. Carolina to Tennessee). This is
the best grazing occultation in North America this year, being the
only one with a first-magnitude star on the dark side of a crescent
Moon at night; in s.e. S. Carolina, the graze might be seen without
optical aid, although steadily-held binoculars are recommended for a
better view with the moderate twilight that will be present. Let me
know if you can join an expedition that I plan to lead from the
Washington, DC area to observe the graze from parts of Charleston,
SC, or areas near there. The path passes over parts of Winnipeg, MB;
n.e. of Minneapolis; n. Illinois; s. Indiana; and over Louisville,
KY, in daylight for these places, the graze being visible with a
small telescope if the sky is clear. The event becomes spectacular
farther southeast as the sky darkens, with the path passing near
Knoxville, Tenn.; w. of Asheville, NC; and over parts of Greenville,
Orangeburg, and Charleston, SC, as well as a short distance s.w. of
Columbia. Southwest of the mile-wide graze zone, a total
occultation can be seen, from western and southern N. America, the
Caribbean Sea, and northwestern S. America, as described on pages 56
and 57 of the June issue of Sky and Telescope. Predictions of the
occultation are also given for several dozen cities on a page of the
main IOTA Web site, including a map showing the region of
visibility, here. The S&T article is good for the view of the Moon
showing the path of the star for several cities. The graze will
appear like the path for Chicago, only a little farther south so
that the line is tangent to the Moon's disk with the bright star
approaching the Moon from the dark side. The graze line is path
#123 on p. 149 of the RASC Observer's Handbook for 2007 (those maps,
as well as tabular details of the graze, are also here). The graze
will last one to three minutes.
You can zoom in on the path in great detail using the Regulus or
ZC 1487 link on Brad Timerson's graze page or directly here.
For the interactive map, you need to enter different values for the
gray offset lines depending on the area you want to map the path.
For South Carolina, the offsets are +0.8 and -1.6 (these are
distances in km from the northern limit line, plotted in green; the
most multiple events are likely in the area between the northern
offset line and the green northern limit line). These offsets are
good for the path across South Carolina, and also for Manitoba,
where the position angle of graze is the same as in S. Car.
These offsets don't take into account height above sealevel, which
will move the zone toward the southwest for areas northwest of
Columbia, SC; Brad Timerson now has two interactive maps for
Regulus, one for sea level (appropriate for most of S. Carolina) and
the other for an elevation of 250m (about 800 ft.), which will be
good enough for the whole path from Louisville, KY to Minnesota. In
Illinois and Indiana, the graze zone offsets are +0.5 and -1.0.
I've used the above site, and information above, to create several
static maps of the path, and have put them in Power Point files
described below:
Overview - 3 maps from Charleston, SC to s. Manitoba
- the local times of the start of the 3-min. graze period and the
Sun's altitude are given near the edges of each map.
Path over Illinois from Odell (I-55) to
Danville (I-74), with detailed views around Odell and Potomac, IL.
Path over S. Carolina - 4 maps show the
path from Charleston to Greenville.
Path over Charleston, SC area - about 1.5
megabytes, this shows detailed views of sites that my
expedition from the Washington, DC region may use from the
south side of Charleston to s.w. of Summerville.
Brad Timerson has now posted predicted profiles at 1-deg. intervals
of longitude across SC on his graze Web site, as well as for
Winnipeg and one or two other places, including appropriate
previously-observed graze data points that define the actual profile
more accurately than the smooth "Watts" profile.
The graze will be an interesting spectacle to watch, but even better
if you can time or video tape it; for information about timing,
click here or read the IOTA online observing manual. Conditions are
good enough in the Charleston area that the graze can be accurately
recorded just by pointing a manually-focused camcorder at the Moon.
As noted below, Steve Welch is planning an expedition in Wisconsin,
and Bob Sandy and Stuart Levy plan to observe from eastern Illinois,
probably near the town of Potomac n.w. of Danville. There will also
be an effort from Winnipeg, but the weather forecast is poor in that
area.
_____________________________
Based on the Astro Meteo 37h prognosis charts for 1h UT June 20 UT,
the Washington, DC expedition does plan to try to observe this graze
in the Charleston, SC area. The forecast is not perfect, showing
maybe 50% cover of cirrus clouds, and poor transparency, in the
Charleston area, and worse farther west. But Regulus is bright, it
will shine through all but the thickest cirrus clouds, and this is a
rare opportunity, so we will take the chance. The clouds are worse
farther west, but even around the path in n.w. SC, the map shows
sizeable breaks in the cloudcover. It'll be cloudy across Tenn. &
Kentucky to about Bloomington, IN, and then thin clouds n.w. of
there almost to Danville, IL, where it should be clear. It will
also be mostly clear from there to northern Minnesota, with a few
clouds possible in n.w. Illinois & southermost Wisc.
First below I give much information for S. Carolina observers, and
then S. Messner's and other messages about efforts in the Midwest.
______________________________
From: David Dunham [dunham@starpower.net]
Sent: Monday, June 18, 2007 1:30 AM
To: ewarner@umd.edu
Subject: Naked-eye graze of Regulus Tues. pm, June 19, & DC-area
expedition to Charleston, SC
Elizabeth, and others,
I'll answer your questions below, for the benefit of many
others (Bcc'ing to them) as well. I think that the observers that
you are coordinating with are in the Columbia area, so they will
probably want to set up an effort on their own about 15 miles
southwest of Columbia; maybe a few of them would want to join our
effort in Charleston to optimize weather chances.
[new 5 pm EDT: We plan to leave Greenbelt, MD by about 8:30 pm
and plan to stay at a motel, hopefully with internet, at Roanoke
Rapids, NC, just s. of the VA line.] We'll check the forecast, and
the visual satellite loop, again Tuesday morning; we might cancel
then if the forecast has worsened. Anyway, while travelling, I
should be reachable by cell phone at 301-526-5590 and at my office
e-mail david.dunham@jhuapl.edu via my Blackberry. NOTE that even if
we cancel, Dave Crum from Jacksonville, FL, has a motel reservation
in Charleston and plans to try to observe the graze, regardless of
the weather forecast. If you might be trying this graze anywhere in
S.C., please send your cell phone number, if you have one.
At 10:47 AM 6/15/2007, you wrote:
>David,
>
>What do you need from the folks in SC to prepare for the graze??
- Any telescope, or even binoculars (and maybe even naked eye) can
be used to observe this. If possible, they should bring any
recording device to help time the occultation, either a tape
recorder, one of the small digital audio recorders available from
Radio Shack, or, best, a camcorder or other video recording device
with a camera. Video recording the graze will give the most
accurate results and should be attempted, if that equipment is
available (if not, visual timings with audio recording is very
useful, too). Regulus is bright enough that many camcorders will be
able to record the star directly with manual focus and the highest
optical zoom capability; using a tripod will help to give a steady
view. Another way, to get a brighter image of the star, is to point
the camcorder into the low-power eyepiece of a clock-driven
telescope. The telescope should be clock-driven in this case
because it's too difficult to both adjust the telescope's pointing
during the graze as well as holding the camcorder to keep it pointed
into the eyepiece to keep Regulus in view. More on timing
occultations is on my Web site at
http://iota.jhuapl.edu/timng920.htm (hot link to this above)
Also, we have extra video systems that can either be used with one
of our small telescopes, or with someone else's telescope, which
just needs a standard 1.25" eyepiece holder. We could certainly use
local observers to stay with what would otherwise be unattended
stations, to keep Regulus in the video field of view, if necessary;
to turn the recorder on before the graze and turn it off afterwards;
and to provide security for the equipment.
>Most of them (the ones I'm in touch with) have never recorded a graze
>before... although some have possibly observed one or two...
>
>Will they need any GPS?
- That's useful for determining observing site locations, but not
necessary if they join our expedition, since we'll have them. One
should not give up if they need to observe independently and don't
have a GPS; they should just note exactly where they are, specifying
within 10 or 20 feet, relative to easily-identified landmarks, and
someone from IOTA (or anyone else with a GPS receiver) can visit the
site later to get its accurate coordinates.
>What should they use for a time signal for recording?
- If they have a shortwave receiver or one of the old Timekubes,
they can use WWV at 5, 10, or 15 megahertz; 10 will probably be best
at the time of the graze. But if they don't have a shortwave, they
should record the standard-broadcast AM radio station WHAS at 840
kilohertz with their car radio; WHAS is a powerful clear-channel
station in Louisville, KY that can be received throughout the
eastern USA. We will be recording it along with accurate time
signals at one station, so that others can use it as a secondary
time base. Some advanced observers might have GPS video time
inserters such as the Kiwi OSD from www.pfdsystems.com , and if so,
they should use them instead, but I assume that most won't have
that.
>Are there any particular characteristics/preferences for the site??
- Yes, one with clear skies and twilight not too bright. That might
limit us to sites around Charleston; they should be the best. Since
the Moon will be nearby, as well as some twilight, we don't need to
observe from dark locations; we can live with high amounts of light
pollution for this bright event. For our expedition, we want to
observe from sites along a road that cuts across the graze zone
roughly perpendicular to it (to give easy access to the whole path)
with several possible observing sites near the road (or near nearby
roads). Regulus will be 34 deg. above the western horizon (azimuth
262 deg.) so we need a view in that direction. The main requirement
then is that observers can safely park their car, and that the trees
are not so dense that there isn't a view in the required direction.
Regulus will be high enough that we don't need a really low,
unobstructed horizon, but do need spaces between trees where we can
see 34 deg. altitude (slightly higher than Polaris in that area).
[Since writing the below, I've found what I think are better sites
in more rural country s.w. of Summerville, near US 17 about 20 miles
n.w. of Charleston; most likely, we would use sites along Embassy
Dr., and would meet (no later than 8 pm) at the intersecion of it
and Orangeburg Rd. (State Hwy S-18-22) - see the maps in the large
Charleston-area Power Point file. But if the clouds are moving in,
such that there could really be an advantage being as far southeast
as possible, we'll switch back to the sites I've described below in
southern Charleston.]
It's far from perfect, but I think the best compromise is to observe
from sites near Ft. Johnson Rd. in southern Charleston; maps in the
1.5 megabyte Power Point file (link to it above) pinpoints that area
of southern Charleston, with the graze zone extending from Ft.
Johnson Rd's intersection with Dills Bluff Rd. to Picadilly Dr. Near
the northern limit line, on the north side of Ft. Johnson Rd.,
between Seaside Ln. and Grand Concourse St., is what appears to be a
large high school; I propose meeting in the parking lot of that
school as close as possible to Ft. Johnson Rd. Observers should
meet there by 8:00 pm; if they can come earlier, they'll have more
time to set up for the graze and might help us find suitable sites
and obtain permission from local residents [telling them that there
will be a rare eclipse of a bright star by the northern edge of the
Moon visible in a mile-wide zone that passes over their house, and
asking permission to set up a telescope beside their driveway (or
other suitable place) for about an hour, until shortly after the
event, and point out that they can see it as well with binoculars
(or on your video screen, if you'll be recording)]. Let me know if
anyone can help with scouting out sites before we arrive in the area
in the mid-afternoon. I have detailed maps in the Power Point file
for the Charleston Country Club area near Routes 30 and 171, and
west of town, near Shadow Moss Golf Club, but these alternate areas
don't seem to be as good as the Ft. Johnson Rd. area. But I don't
know anything about the neighborhoods of Charleston, which ones
might be better than others for this. Any advice would be welcome.
David Dunham
>Elizabeth Warner
>warnerem@astro.umd.edu
>
>(webmaster@midlandsastronomyclub.org)
>
>Date: Fri, 15 Jun 2007 10:19:28 -0400
>From: Paul Romanyszyn
>User-Agent: Thunderbird 1.5.0.12 (X11/20070509)
>MIME-Version: 1.0
>To: Hap Griffin
>CC: john hodge ,
> MAC Board
>Subject: Re: [board] Re: Spectacular occultation and graze of Regulus Tues.
> pm, June 19
>
>What sources of GPS and WWV will we have.
>I will try to use the Meade video eyepiece with a telescope and VCR to
>record this.
>The location may have to be picked a few hours ahead of time watching
>for holes in the clouds.
>Paul
>
>Hap Griffin wrote:
>>We have plans in the works. Paul and Al Parker are trying to get us a
>>location in the grazing occultation path.
>>
>>Hap
>>
>>----- Original Message ----- From: "john hodge"
>>
>>To: "Paul Romanyszyn" ; "Hap Griffin"
>>; "MAC Board"
>>Sent: Friday, June 15, 2007 8:04 AM
>>Subject: Fw: Spectacular occultation and graze of Regulus Tues. pm,
>>June 19
>>
>>>Guys: Lets get an obseving group organized to take some observations
>>>for this!!! I will not be out of town and will be around. It would
>>>be nice if MAC contributed to observation of the occultation. JOHN
______________________
[IOTAoccultations] Spectacular occultation and graze of
Regulus, Wisconsin
Hi,
The person I was going to observe with was unable to, so I will be
observing from a site much closer home than I was thinking before.
The site I chose is about 2 miles West of Eau Galle Wisc. There are
maps to the site along with other files and a few links on the
http://www.harvestmoonorchard.com/hmoon/Regulus_graze.html
http://www.harvestmoonorchard.com/hmoon/Regulus_graze.html
or
indirectly here http://www.harvestmoonorchard.com/hmoon/ At the
moment the weather sounds OK. The occultation occurs around 7:50PM
CDT from that site. I hear that Bob Sandy may be observing from Ill.
but that's farther than I want to drive. Please let me know if you
can join in!
email me or call 612-770=3113 cell
Clear Skies,
Steve Messner
email smessner@rconnect.com
Harvest Moon Observatory
Northfield, MN
18" Newt. pc164, Kiwi, WAT-902H2 ULTIMATE Upper Mid-West Occultation
page-
http://www.harvestmoonorchard.com/astro/occultations/index.html
_____________________________
From: Stuart Levy [slevy@ncsa.uiuc.edu]
Sent: Monday, June 18, 2007 2:29 PM
To: Dunham, David
Cc: Stuart Levy; MO Blue Springs Sandy, Bob; MO St Louis Wayne Clark
Subject: Re: [IOTAoccultations] graze of Regulus Tues. pm, June 19,
efforts in the Midwest
On Mon, Jun 18, 2007 at 02:07:59PM -0400, Dunham, David wrote:
> Stuart,
>
> As you've probably noticed on Timerson's graze Web site, he has a
> version of the Regulus interactive map for 250m altitude above sea
> level, which is good enough to use for all of Illinois and Indiana.
> The profile offsets to use in Illinois/Indiana from that line are +0.5
> and -1.0 km. That path goes right over Danville, as you might have
> seen in the Power Point file.
>
> Bob Sandy and Wayne Clark are planning to drive from Missouri to
> observe the graze in Illinois. They're planning to observe either
> near Odell (near I-55) or near Potomac. Maybe they could select
> Potomac as their main site; then they could stop in Champaign to pick
> you up, and possibly join any others, who might want to try it from
> your area. What phone numbers could Bob or Wayne reach you by to coordinate plans?
>
> David
Cool! Potomac looks good -- though I've never been there, it's on a
decent-sized road, but one that's much more approachable than an
Interstate as Danville is on.
My cell phone number is 217-369-3485. Though I have telescopes, a
WWV receiver, audio cassette recorder, and some 110V-powered video
gear, I don't have anything like a camcorder. But given that, I'd
be glad to help if they do end up choosing to go this way.
Stuart Levy
In a later message, Bob Sandy confirms that they plan to travel to
Champaign, IL to meet Stuart Levy to observe probably near Potamac.
2007 June 18, 21h UT
David Dunham, dunham@starpower.net, 301-474-4722, cell 301-526-5590
Office david.dunham@jhuapl.edu phone 240-228-5609