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Don't Miss Wed Morning Occultation- *Pre-sketch

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#1 markseibold


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Posted 20 April 2009 - 05:00 PM

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I decided to do a pre-sketch from practiced imagination and observing experience. I submitted the work to Spaceweather. (Again really not finished as I just refined it *above here)
Dr Tony Phillips of www.Spaceweather.com had already posted it, so now you can compare the refined version. I was hoping to hear from other Portlander's if I got the downtown skyline correct. I wrote to Spaceweather that I imagined the view from Council crest above downtown at 1024' ft elev. However the view is more so from Washington Park in the International Rose Gardens just above the downtown Portland skyline with our guardian Mt Hood on the east horizon peaking at 11,245'. *I reworked the lunar mare, the mountain and the sunrise sky light. I am as much intent on accuracy of the landscape as the sky. I placed Mars rising below at just above the horizon.


To all

I just thought I'd remind you to mark your calendars and set your alarm clocks for an early rise to see the lunar occultation of Venus Wednesday morning before sunrise for those on the west coast. I have simulated a rough sample of what might be seen as naked eye and through a telescope as Venus is at its largest crescent phase now. Many may remember Dee's great impressionistic sketch featured in Astronomy Picture of the Day December 6th 2008.

Good luck to all in sketching this event! - Mark
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Through a telescope just before the first contact >
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#2 kraterkid


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Posted 20 April 2009 - 05:54 PM

Thanks Mark,

When exactly? :question:

#3 markseibold


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Posted 20 April 2009 - 07:01 PM


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.

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
Happy observing,
Stan and Jan


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 >

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#4 varmint


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Posted 20 April 2009 - 11:17 PM

Thanks for the reminder Mark. If I can get up and get to work early enough I'll give it a shot, though I probably won't be able to sketch it. At work we have a couple of buildings that are on hilltops with a nearly unobstructed eastern horizon. I'm just hoping it's high enough to see above the distant hills (and the fog/clouds don't really roll in like they're slated to around here...)

#5 kraterkid


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Posted 21 April 2009 - 12:25 AM

Thanks Mark, Maybe I'll have a go at sketching the event through my Pronto, though my horizon is ringed with distant desert hills. I'll need to hunt down a good vantage point.

#6 CarlosEH



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Posted 21 April 2009 - 01:29 AM


Thank you for the update on the Moon and Venus conjunction. I hope that many of us get to witness it.


#7 frank5817



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Posted 21 April 2009 - 10:26 AM


Thanks for the reminder. I have a slight chance of seeing this event if our cloudy weather breaks up.

Frank :)

#8 markseibold


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Posted 21 April 2009 - 12:07 PM


You are all welcomed. I hope many others will observe and try to sketch.

I kind of took the jump on the event (artistic license as Tony Phillips of Spaceweather calls it on his front page today) and mocked up a pre alert large pastel sketch last night over Portland from the West Hills (Portland's Washington Park Rose Garden, a ways up in elevation but I mistakenly labeled it from Council Crest as the Portland buildings were all done from memory as I have them indelled into my mind as a native here) sent it to www.spaceweather.com last night. I wasn't really finished with it as portions of it that I wanted to refine I may rework today, but Dr Tony Phillips of Spaceweather already posted it to his front page as a reminder to all.


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