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Centaur
2012-May-19, 08:17 PM
Iíve created Venus transit previews for 44 cities. The diagrams employ horizontal (alt-az) coordinates with zenith at the top. The apparent curved path of Venus is due to the Earthís rotation. Unlike generic diagrams with straight paths utilizing geocentric equatorial coordinates, mine show how the transit will actually appear in the sky at specific locations.

The highly accurate Solex numerical integration software was utilized to determine the bodiesí relative positions at various times. Due to the parallax effect, event timings would vary among the locations even if adjusted to Universal Time.

The index to the 44 cities for my transit previews can be found at: www.CurtRenz.com/venustransit

KaiYeves
2012-May-19, 09:35 PM
Thank you. I'll keep the Washington DC one on-hand. Hopefully, I'll be able to see it from the Naval Observatory if the weather's good and the line isn't too long.

Ara Pacis
2012-May-21, 06:21 AM
I'll be sure to bring my ND filters to that photoshoot.

Centaur
2012-May-26, 07:10 PM
Thank you. I'll keep the Washington DC one on-hand. Hopefully, I'll be able to see it from the Naval Observatory if the weather's good and the line isn't too long.

You're welcome, KaiYeves. The USNO should put on a good show for you. I hope Mother Nature keeps the sky clear for you. :)

grapes
2012-May-26, 07:13 PM
Thanks, Curt, looking forward to it. :)

Jens
2012-May-28, 03:53 AM
I hope you'll consider doing a few more for the geographically challenged among us, who aren't in major Anglophone cities!

Tobin Dax
2012-May-28, 04:15 AM
Thanks, Curt. One correction: Nashville is in the Central time zone.

Centaur
2012-May-28, 06:41 PM
I hope you'll consider doing a few more for the geographically challenged among us, who aren't in major Anglophone cities!


Well, Jens, please understand that analytics indicate virtually all of my website visitors are from Anglophone countries. And almost all of those are from North America. Actually, I get far more grumbling from North Americans whose localities are not on the list. Sorry, but there was a limit as to how much time I could devote to this project. However, that presents a fine opportunity for you to create diagrams for the rest of the world. :)

Centaur
2012-May-28, 06:43 PM
Thanks, Curt. One correction: Nashville is in the Central time zone.

You're welcome, Tobin Dax. Thanks for the Nashville correction. It's now fixed. :)

KaiYeves
2012-May-28, 09:56 PM
Actually, now that I know they'll be having observing, I might go to the Smithsonian observatory rather than the Naval Observatory, and it's closer on the Metro to my residence.

Centaur
2012-Jun-03, 04:56 AM
Thanks, Curt, looking forward to it. :)

You're welcome, Grapes. May your skies be clear!

Ara Pacis
2012-Jun-05, 11:37 PM
$$%^&^*%$#!!! As soon as the transit starts, we get a low cloud deck moving in. :(
Maybe it will clear before sunset. I don't want to wait another 105 years.

grapes
2012-Jun-05, 11:51 PM
You're welcome, Grapes. May your skies be clear!You did it! At six o'clock the sky looked like this, and then it cleared enough to get some decent shots. The sun set before it was half over, but my favorite shot is this one in the clouds--you can see sunspots poking through too.
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Centaur
2012-Jun-05, 11:54 PM
$$%^&^*%$#!!! As soon as the transit starts, we get a low cloud deck moving in. :(
Maybe it will clear before sunset. I don't want to wait another 105 years.

Sorry to hear that, Ara. Perfect weather here in Chicagoland. I can confirm that my prediction times were correct. If you miss the transit today, then just keep exercising and eating right. ;)

Ara Pacis
2012-Jun-06, 05:07 AM
Sorry to hear that, Ara. Perfect weather here in Chicagoland. I can confirm that my prediction times were correct. If you miss the transit today, then just keep exercising and eating right. ;)The skies did clear and I got it for the last hour and a half before sunset. Unfortunately, my optics weren't up to par. I'm using an old 4MP DC I had for the last transit and without special solar filters I had to use a bunch of NDs and an IR plus two telephoto converters to make it big enough to see (even though the DC has 10x (380mm 35mm equivalent).

Attached in front of my camera lens was a ring adapter, a 2x converter and held in front of that was a 1.8 converter and held in front of that was a circular polarizer, 8xND, 4xND, 2xND and for some of the shots an R72. With the R72 I see swirls, but I don't know if it's something in the filter or solar cell structure -I think it's mostly JPEG compression artifacts. Maybe I should have used my IR1000 filter, but I forgot it when I went up to the ridge (the sun had set in the valley). None of the images came out super sharp, but with that many glass-air interfaces and low to the horizon, it's no wonder. I didn't use a tripod, but I don't think it would have mattered since I was shooting at 1/1000th of a second... although it was a lot of magnification ~1008mm (35mm equivalent).

The first one included the IR filter. The second was without the IR and included digital zoom, and it was also sunset, with the sun dipping into the trees on the other side of the valley.
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