• Security incident: ISF was recently accessed by intruders. Please change your password, and change it anywhere else you used it. Read more

Transit of Venus photography

Biscuit

Philosopher
Biscuit
Joined
Aug 16, 2007
Messages
6,929
So I am getting ready for my second transit of Venus and since the last one my participation in solar astronomy has waned a bit. Get it? Waned?

Anyway I just got my Orion built adaptor to attach my iPhone 4s to an eyepiece.

Product details here

And as I used to work for Coronado instruments I have access to several dedicated hydrogen alpha telescopes including a PST and a solar max 40. I am wondering what is the best app for photography on an iPhone? I believe I will need an app with an adjustable iso setting to get results like in my profile pic. Any app suggestions would be great.

I a planning on setting up at least one telescope for the transit and if you are in the Tucson area and would like to see this unique event let me know.
 
Not sure what settings you can adjust on your camera, but this was taken at f/8 1/125 sec exposure, ISO-64 with my fuji finepix & a H-alpha filter
 

Attachments

  • DSCF0611.jpg
    DSCF0611.jpg
    42.4 KB · Views: 18
I ended up finding an app that I think will work called 645 pro. It was cloudy yesterday but I might get some pics today.

I strongly recommend seeing the transit if you can.
 
Not trying to hijack the thread, but rather than start a new one...

Why is it that a transit of Venus is so rare? They're saying it will be more than a century before the next one. My grade-school picture of the solar system has all the planets (now that we can disregard Pluto) revolving in a plane like tracks on a vinyl LP. Venus must zip around the sun a time or two every year (sorry, too lazy to look it up) since it's closer to the sun. Why isn't a transit of Venus an annual event? The only thing I can think of is that "the ecliptic" isn't really that planar, and the Earth is up when Venus is down or vice versa. If that's the whole explanation, how "out of line" are the planets?
 
zeggman said:
The only thing I can think of is that "the ecliptic" isn't really that planar, and the Earth is up when Venus is down or vice versa.
Click to expand...

It's exactly this. Venus has to pass through a 1/2 degree spot in the sky when the three bodies are lined up and that just doesn't happen often. Venus's orbit is tilted at about 3.4 degrees to the ecliptic. All of the other planets are comparable, 1-4 degrees-ish. Pluto is substantially out of the ecliptic, at 17 degrees. Earth is the next most poorly behaved of the planets in the solar system, actually, with an orbit that is 7 degrees off of the sun's equator (which is different than the ecliptic plane.)

It's only a few degrees, but it makes a big difference. Even Mercury, which orbits much more quickly and is much closer to the sun to begin with, doesn't transit the sun terribly often, a dozen times a century or so, as I recall.

ETA: The alignments don't happen as often as you'd think, either. If you imagine this as a race, with Earth and Venus starting out at the same line today, Venus has to lap Earth to catch back up for a potential alignment. When it finishes its first lap, it's 140 days ahead of Earth. After two laps it's 280 days ahead, and it's not until about halfway through the third lap (very roughly 2.5 years in this example, actually a bit longer) that it actually catches up to Earth again and another transit is possible. With alignments only happening every few years and that alignment having to occur in a few day period in either June or December (that's when the orbits happen to line up right) it becomes clearer why they are so rare. An interesting bit is that the transits always come in pairs spread by 8 years. When you check, 8 Earth years is very close to 13 Venus years.
 
Last edited:
Thanks. I guess it seems to me that the sun fills more than 1/2 a degree in the sky, but I guess that (along with the vast differences involved) would make a difference. I appreciate your taking the time to answer.
 
The Moon is also a 1/2 degree across.
Makes for those nifty total and annular eclipses based on its distance from the Earth and position in the orbit.
 
Last edited:
jasonpatterson said:
ETA: The alignments don't happen as often as you'd think, either. If you imagine this as a race, with Earth and Venus starting out at the same line today, Venus has to lap Earth to catch back up for a potential alignment. When it finishes its first lap, it's 140 days ahead of Earth. After two laps it's 280 days ahead, and it's not until about halfway through the third lap (very roughly 2.5 years in this example, actually a bit longer) that it actually catches up to Earth again and another transit is possible.s.
Click to expand...
Sorry, I'm not following this at all. Still haven't looked up the "Venusian year," but it seems you're saying it's 140 days. I can accept that Venus returns to "the same line" after 140 days, but if it's back again at 280 days it seems it must have passed between the Earth and the Sun to get there -- "lapped" the Earth, as you put it.

What am I missing/misunderstanding?
 
Okay, I did look it up. The "Venusian year" is 225 days, so your 140 was 365-225. Now it makes sense - when Venus is back where it was, Earth is almost 2/3 of the way around too. So, even though Venus orbits the sun in less than a year, it isn't that much less, and it takes 2.5 years to "lap" it.

Thanks again.
 
Crap. We've got enough clouds here to make it look like I'm on Venus.
 
Just checked where I am. No clouds, just got wait for the sun to rise above the horizon. Knowing my luck it would take a sickie today and not rise. LOL.
 
Psi Baba said:
Crap. We've got enough clouds here to make it look like I'm on Venus.
Click to expand...


Same as. We'll get approximately one hour of the transit but it doesn't look like we'll even be able to see the sun.

Still, wifey has just set the alarm for 04.45, hope springs eternal.
 
You must log in or register to reply here.

Share this page

ISF - Join now!

Every member here is approved by hand. No bots, no spam, just people who care about evidence and honest debate.

Membership is free!

Create your free account

Back
Top Bottom