Total Eclipse July 11, 2010 - Weather Odds?

A total eclipse of the sun will be visible in remote locations around the South Pacific on July 11, 2010. (http://www.space.com/spacewatch/solar-eclipses-july-11-100702.html) At maximum duration, the moon will completely cover the sun for more than five minutes. Given that this is a special event, many tour companies are organizing expensive excursions to bring viewers to these remote locations, however, many of the more easily accessible areas have a 40% or more "chance" of clouds obscuring the view.

How are odds regarding the weather calculated? When the report says, "a 50% chance of rain", what does that mean? Half the area in question will get rain?, 12 of the 24 hours will have rain?

I think a "50% chance of rain" means that for any specific point within the area of prediction will have a 50% chance of seeing at least one drop of rain. For example, if the chance of rain is 50% for Las Vegas tomorrow, then the chance would be 50% that a random point in Vegas would get wet.

Not that I believe in luck, but I'll hope for the best for the eclipse watchers. I know I lucked out with the clouds in China last year for the July 22, 2009 eclipse. It was forecast to be a washout, but the clouds cleared just in time.

Quote: Ayecarumba

A total eclipse of the sun will be visible in remote locations around the South Pacific on July 11, 2010. (http://www.space.com/spacewatch/solar-eclipses-july-11-100702.html) At maximum duration, the moon will completely cover the sun for more than five minutes.

Can totality last that long? If it can, that will be a spectacular event. I mean spectacular for a total solar eclipse.

Quote:

How are odds regarding the weather calculated? When the report says, "a 50% chance of rain", what does that mean? Half the area in question will get rain?, 12 of the 24 hours will have rain?

I suppose by looking at the average rainy and cloudy days in the particular region for that time frame. Mex City gets most of its rain in the summer and it's often cloudy, too. The chances for the Great Eclipse of 91 to be clouded-out were high, but the clouds broke partially over large areas of town.

Here is a portion of the info provided by the National Weather Service...link uses is http://www.srh.noaa.gov/ffc/?n=pop

"Mathematically, PoP is defined as follows:
PoP = C x A where "C" = the confidence that precipitation will occur somewhere in the forecast area, and where "A" = the percent of the area that will receive measureable precipitation, if it occurs at all.

So... in the case of the forecast above, if the forecaster knows precipitation is sure to occur ( confidence is 100% ), he/she is expressing how much of the area will receive measurable rain. ( PoP = "C" x "A" or "1" times ".4" which equals .4 or 40%.)

But, most of the time, the forecaster is expressing a combination of degree of confidence and areal coverage. If the forecaster is only 50% sure that precipitation will occur, and expects that, if it does occur, it will produce measurable rain over about 80 percent of the area, the PoP (chance of rain) is 40%. ( PoP = .5 x .8 which equals .4 or 40%. )

In either event, the correct way to interpret the forecast is: there is a 40 percent chance that rain will occur at any given point in the area."

For some of us older folks living in the US, let's hope to hold on until 2017...

2017 eclipse

Quote: Ayecarumba

How are odds regarding the weather calculated? When the report says, "a 50% chance of rain", what does that mean? Half the area in question will get rain?, 12 of the 24 hours will have rain?

After enduring years of inaccuracy by our local TV weatherman, I contacted him directly and we had a rather heated argument about this that went on some days via email and phone. He said that "20% chance of rain" meant it *would* rain over about 20% of the area. What area? The TV viewing area? What if that extended 100s of miles? What does "chance" mean here? He quoted all these experts for this definition and touted his credentials. He would say this on TV just about every night, no matter the % of rain, that it *would* rain tomorrow over whatever %.

But, he is wrong. [edit. See definition above by Ron C. correcting and clarifying my comments]

About 2 weeks after our argument, he adopted my language and meanings on his evening weather-cast, and has never used his lame definition since that time. Nevertheless, if you explore this topic on the Internet, you will still find both definitions.

--Dorothy

Quote: Mosca

For some of us older folks living in the US, let's hope to hold on until 2017...

2017 eclipse

I'm planning to catch that one in Idaho Falls.

Quote: Wizard

Quote: Mosca

For some of us older folks living in the US, let's hope to hold on until 2017...

2017 eclipse

I'm planning to catch that one in Idaho Falls.

I've been eyeing up Charleston, SC for this one. It really depends on where I'm living at the time. There's a likelihood I'll be living in Chicago, and if that happens, then I'll be heading to the point of greatest totality. If I'm still in NJ, Charleston it is.

When the Wizard posted his trip report for the China eclipse, I found it very educational. I exchanged email with him, noting I have a photo on my wall that I shot during what the media claimed was a total eclipse in Atlanta in 1984. From his trip report, I finally recognized that the Atlanta event was actually an annular eclipse and not a true (very rare) total eclipse. I told him I hoped to see the 2017 event if I can live so long. I will probably start planning my viewing site about 2016, if I am still alive then. Hey, wouldn't that be a great date to have a meet-the-Wizard coffee? Then we could seek out an Idaho casino. :-)

Quote: Doc

Hey, wouldn't that be a great date to have a meet-the-Wizard coffee? Then we could seek out an Idaho casino. :-)

I know you are being facetious but there aren't any casinos in Idaho that would be suitable for viewing the eclipse. Actually, the best casino to view the eclipse from would be Terrible's St. Jo Frontier Casino in St. Joseph, Missouri, with 2m38s of totality. Harrah's Cherokee, that abomination of a "casino," is also in the path, as are a couple in Oregon.

If only there were some way to also involve license plates...

Quote: teddys

I know you are being facetious but there aren't any casinos in Idaho that would be suitable for viewing the eclipse.

For a total eclipse and a Wizard's coffee, I'd bring cards, chips and a foldout table. Anyone have a telescope? Total eclipses are usually the best times to see Mercury.

Quote: teddys

If only there were some way to also involve license plates...

I still have one almost identical to the one I passed on as a token to the Wizard in April (one digit different, I think). So if any one else is a collector, or if the Wizard needs one for a swap meet, I could put that on the table. Hmmm, would they accept one of those at a casino table?

As for Idaho casinos, yes, I was being facetious. I have never been to Idaho, so maybe an eclipse would be my justification for traveling to that neck of the woods (provided I survive to 2017) even without the casino action. As for alternate casino locations in the eclipse path, the Cherokee joint is the closest casino to my place. Visited it once in 2006 and have no desire to return.

Quote: Nareed

Total eclipses are usually the best times to see Mercury.

I wonder whether Mercury shows up in the photo I have of the 1984 annular eclipse, if I knew where to look and tweaked the image. The photo does show Bailey's beads quite well. Is there a good way to go back and determine where Mercury should have been located in the image if it were not aligned with the sun/moon?

Quote: Doc

When the Wizard posted his trip report for the China eclipse, I found it very educational. I exchanged email with him, noting I have a photo on my wall that I shot during what the media claimed was a total eclipse in Atlanta in 1984. From his trip report, I finally recognized that the Atlanta event was actually an annular eclipse and not a true (very rare) total eclipse. I told him I hoped to see the 2017 event if I can live so long. I will probably start planning my viewing site about 2016, if I am still alive then. Hey, wouldn't that be a great date to have a meet-the-Wizard coffee? Then we could seek out an Idaho casino. :-)

Doc, are you a photographer? If so, you'll be interested in this:

The Online Photographer: It's Never Too Early to Start Planning for an Eclipse

Quote: Mosca

Doc, are you a photographer? If so, you'll be interested in this:

The Online Photographer: It's Never Too Early to Start Planning for an Eclipse

I am an amateur/hobby photographer, focused mainly on scenic images from my travels. We have what seems like a gazillion photos on the wall of our condo. It helps in frequently reliving the travel experiences.

Thank you very much for the link. I have copied that article into the same computer folder where I saved the Wizards trip report -- saving my reference info just in case I make it! My 1984 eclipse photo was taken with 35mm color transparency film and direct-positive printed to hang on my wall (it looks very much like a B&W image). In 2003, I converted strictly to digital images -- now I am doing a better job of keeping up with and organizing all of my photos, and the "darkroom" work (what is left of it) is now done on an iMac.

Quote: Doc

I wonder whether Mercury shows up in the photo I have of the 1984 annular eclipse, if I knew where to look and tweaked the image. The photo does show Bailey's beads quite well. Is there a good way to go back and determine where Mercury should have been located in the image if it were not aligned with the sun/moon?

I suppose there must be some sort of sky map which can be adjusted to show what the sky looked like at any given date and time at a particular location. But I don't know of any. Try Google and work your way from there.

According to Wikipedia Mercury can have a magnitude of up to -2.3 as seen from Earth, which makes it much brighter than Sirius. Flip side is it can be as low as 5.7, which is pretty low but still visible to someone with normal vision. If Mercury was close to the sun at the time of the eclipse, and the glare didn't drown it out (annular eclipses vary in brightness), it might be visible if it wasn't behind the Sun

Problem is Mercury always is close to the Sun. It's visible for short periods around dawn and sunset, very low in the sky. During a total solar eclipse it's visible high in the sky, when the Sun's glare is covered by the Moon.

Quote: Doc

Quote: Mosca

Doc, are you a photographer? If so, you'll be interested in this:

The Online Photographer: It's Never Too Early to Start Planning for an Eclipse

I am an amateur/hobby photographer, focused mainly on scenic images from my travels. We have what seems like a gazillion photos on the wall of our condo. It helps in frequently reliving the travel experiences.

Thank you very much for the link. I have copied that article into the same computer folder where I saved the Wizards trip report -- saving my reference info just in case I make it! My 1984 eclipse photo was taken with 35mm color transparency film and direct-positive printed to hang on my wall (it looks very much like a B&W image). In 2003, I converted strictly to digital images -- now I am doing a better job of keeping up with and organizing all of my photos, and the "darkroom" work (what is left of it) is now done on an iMac.

I resisted amateur photography for years, knowing that I would fall into it face first; a few years ago I gave in. My only issue now is when we travel, I can either make it a vacation, or a photo outing, but not both! Same with an air show; I can see the show, or take great photos, but to concentrate solely on one means I have to completely give up the other, if I want to maximize involvement. If I split involvement, then neither is satisfied. So far, I've fallen on the side of taking the vacation, and watching the air show (I love air shows), and I think that if I were to visit the eclipse I would decide to maximize my involvement in seeing the eclipse and forgo photographing it.

Quote: Mosca

and I think that if I were to visit the eclipse I would decide to maximize my involvement in seeing the eclipse and forgo photographing it.

Good choice. A total solar eclipse is very rare (unless you're willing to travel a lot every year). For many people it's a once in a lifetime deal. It would be a shame to miss it in order to document it.

Quote: Wizard

I think a "50% chance of rain" means that for any specific point within the area of prediction will have a 50% chance of seeing at least one drop of rain. For example, if the chance of rain is 50% for Las Vegas tomorrow, then the chance would be 50% that a random point in Vegas would get wet.

Not that I believe in luck, but I'll hope for the best for the eclipse watchers. I know I lucked out with the clouds in China last year for the July 22, 2009 eclipse. It was forecast to be a washout, but the clouds cleared just in time.

My post-graduate work was in meteorology and I worked quite a bit with the forecasters in Vancouver. Forecasters are unable to predict within 10%. 40% and 60% are just guesses... they like to avoid 50% as it's on the fence and they have a good idea on the side of precipitation or no precipitation.

A 50% chance of rain means that the region has a 50% chance of experiencing rain.

When I photographed the annular eclipse in 1984, I placed the camera on a tripod, pointed it in the general direction of the sun, zoomed in, focused at infinity, and snapped pictures fairly much at random during the event. I did not attempt to look through the viewfinder, and I don't think I missed out on anything that anyone else observed. The print I have on display was just the random shot that best showed Bailey's beads.

My main concern about missing something while photographing a true total eclipse is whether I should be photographing something other than the sun and how many cameras I would want (I now only use one). I recall the whole environment looking rather weird during the annular eclipse and expect the phenomenon would be stronger in true totality. I just don't know whether it is something that would show up in a photograph or is just a sensation when experienced first hand.

I did check the low-resolution star chart on my PDA for Atlanta (33:47N, 84:24W) at the time of the eclipse (11:23 EDT 5/30/84). It appears that Mercury was about as separated from the Sun as it could possibly be, with a magnitude of 0.0. In fact, the planet might even have been out of the field of view of my photo. Venus was possibly hidden behind that eclipse. I need a better understanding of both astronomy and geometry, I suppose. I'm not really into either.

Quote: Doc

I did check the low-resolution star chart on my PDA for Atlanta (33:47N, 84:24W) at the time of the eclipse (11:23 EDT 5/30/84). It appears that Mercury was about as separated from the Sun as it could possibly be, with a magnitude of 0.0. In fact, the planet might even have been out of the field of view of my photo. Venus was possibly hidden behind that eclipse. I need a better understanding of both astronomy and geometry, I suppose. I'm not really into either.

I need a better understanding of astronomy, too. But I do l know an object with a magnitude of 0.0 is easily visible at night. I'm not so sure whether it would be visible during an annular eclipse, when some of the Sun is still showing.

At totality the thing to see is the Sun's corona. Actually it's the Sun's atmosphere, which isn't usually visible due tot he Sun's full light. Many photographers try to get good pictures of it. All I know is it's hard to get a good pic of it, so if you intend to do it I would suggest researching the subject first. You's probably also want to team up with someone else and divvy up the work of photographing inverted constellations, planets and the corona. That also gives you a few minutes to actually watch the show.