Telescope Reviews: Don't Miss Wed Morning Occultation- *Pre-sketch

Rich

I'm glad you asked as I forgot the pertinent info and it is a very narrow window of time -Mark >

PS * I will probably be at the top of Council Crest Park by 4:30 AM in the west hills to observe, photograph and sketch the event.
-Mark

On Mon, Apr 20, 2009 at 2:48 PM, Mark Seibold <markscosmiclight@gmail.com> wrote:

To all

Stan Seeberg of the Vancouver Sidewalk Astronomers has a great write up below to alert you to this event. I might add that you should also get to at least a medium telescope and be on a hilltop with good low eastern horizon views. I have assembled a mock graphic of what to see in a telescope just before the first contact >

Close -up through a telescope you should see this just before Venus slides behind the moon but keep watching as the planet currently its largest crescent phase can be seen (*I have simulated this with use of other photos and photoshop enhancement to give a similar example of what will be seen just before the occultation) will slide behind the moons sunlit cusp to emerge awhile later in daylight but probably not visible for the end of the event. >

As the Moon moves in its orbit around the Earth, it passes in front
of a multitude of stars, the great majority of which are inconspicuous.
Occasionally, however, it moves in front of a bright star or planet,
hiding it from view for awhile. When one celestial body moves in front
of another, the event is known as an occultation.
During dawn this next Wednesday, April 22nd you'll have an
opportunity to witness Venus, our sky's brightest planet being occulted
by the Moon. People observing along the U.S. West Coast can see part or
all of the occultation and in the Pacific Northwest only the beginning
will be readily seen.
To be viewed at all, the observer must have a view toward the east
EXTREMELY close to the horizon. At occultation time even a small
obstruction might prevent it from being seen. The pair will be a scant
few degrees above the horizon as the occultation begins. Trying to
locate Venus a day or two ahead is a good idea. If you can spot it
before Wednesday, you'll be virtually certain to observe the event,
weather permitting. Bright Jupiter is well to the right of Venus and
higher up.
In the Portland/Vancouver area Moonrise on Wednesday occurs at 4:44
a.m. PDT. The Moon will resemble a super thin crescent resembling a
slightly tilted letter "C" with Venus a short distance to its left. The
pair might not be obvious, even from a good observing area, until 5:00
or shortly thereafter.
As the minutes pass the Moon will move closer to Venus along our
line of sight. A binocular or small, low-power telescope will be
useful in watching the ever-closing distance and will be helpful in the
event that haze or thin clouds dim the view. If the sky is clear all
you'll need is your unaided vision. As the occultation begins Venus
will slowly appear to dim, taking about 30 seconds to completely
disappear behind the Moon. When a star is occulted, its disappearance
is instantaneous.
From Northwest Oregon and Southwest Washington, be sure to begin
watching by 5:15 a.m. and continue to stare continually at the pair so
as not to miss the first dimming within a few minutes. The
reappearance of Venus will occur about sunrise and will likely be
unobservable with bright sunlight present. Some of the information
above was obtained from the April edition of Sky & Telescope magazine,
page 56.
The occultation will be a challenge but is defiinitely worth the
effort!
Happy observing,
Stan and Jan

http://www.vsausa.org/

http://www.aaa.org/index.aspx?lobid=950
MOON AND VENUS IN THE MORNING APRIL 22
Venus moved into the morning sky on March 27, and wasted no time becoming visible. Aided by its location well north of the Sun, Venus can already be spotted on April Fool's Day. It continues its speedy voyage, closing in on and eventually passing well north of Mars on the 18th.

However, the highlight this month occurs on the 22nd, when the Moon enters the scene. Only 2½ days from new, the Moon is a very thin crescent. At 4:30 AM the Moon rises, followed about 6 minutes later by Venus. Venus is then only 2¼° from the center of the Moon. The Sun won't rise until after 6 AM, so the sky is pretty dark. You'll probably spot brilliant Venus first, then the thin Moon. On this morning Venus is only 17% lit and the Moon a mere 9%.

It gets even more interesting as the sky slowly brightens. By 5 AM, planet and Moon are 2° apart. An hour later as the Sun is about to rise, 1½°. If you continue past sunrise (with binoculars or telescope), the Moon and Venus will be apart at 7 AM by 30' arc minutes or ½° at 8 AM, and 20' at 9 AM. The two are closest, only 19½' apart at 9:17 AM.

All the above distances are from Venus to the center of the Moon. Subtract 16' (the Moon's radius) to get the distance from Venus to the nearest point of the Moon.

Most of the US will see the Moon actually pass in front of Venus, though in the daytime except for the western states.

Moon and Venus
Naked-eye view 5 AM April 22

Moon and Venus
Telescopic view 9:17 AM April 22

Following is Portland east skyline with close-up of My Hood near where moon will rise >