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Transit of Venus 2012 June 5-6


Transit of Venus 2012 June 5-6

Attached are the Mathcad 14-15 worksheet and input data file used to generate the "Transit of Venus 2012 June 5-6" animation (video) that I posted on February 2, 2012. This is an astronomically rigorous calculation based upon accurate geocentric ephemerides of the Sun and Venus.

If you have not heard about this astronomical event elsewhere, surely you will, for two reasons! Because (1) this is the last transit of the Sun by Venus that anyone now living is likely to ever see. The next pair of Venus transits will occur on 2117 December 11 and on 2125 December 8. And (2) it will be easy to observe (weather permitting) as well as rare.

All you will need is an inexpensive pair of "eclipse glasses," or you can construct a "pinhole camera." But telescopic observation is also possible, with a full-aperture solar filter.

So check out the worksheet and video and be watching your local news media as we approach the month of June 2012.

CAUTION: Never look directly at the disk of the Sun without approved eclipse glasses. Never point a telescope at the Sun without a full-aperture solar filter properly affixed over the objective lens. Further, the finder scope's objective lens should be blocked with a piece of aluminum foil unless it, too, has an approved solar filter properly affixed.

Any questions? First PlanetPTC member to respond gets the points.

Roger Mansfield

P.S. When you view the video, do as PlanetPTC member Kevin Bradberry suggests and click the box in the lower right of the video viewer to obtain the more legible full-screen animation.


Accepted Solutions

Roger, hello!

Well, I have one: could you please advise a telescope for amateur astronomical observations? Maybe from Meade or Celestron models?

View solution in original post


Thank you for this Mathcad worksheet.


You are quite welcome -- do you have any questions?


P.S. Attached is a .pdf version of the worksheet, in case you don't have Mathcad handy.

Roger, hello!

Well, I have one: could you please advise a telescope for amateur astronomical observations? Maybe from Meade or Celestron models?


Good question -- I myself have an 8" Celestron with a full-aperture solar filter. To see the disk of the Sun, I take out the eyepiece and hold a piece of white paper at the prime focus of the telescope, adjusted to lie a few tens of centimeters behind the back of the optical tube assembly. BUT ... this is the hard way!

You don't have to buy a telescope to view a solar eclipse or even this transit. Make a pinhole camera! Here are two links that show in detail how to do so. The first is from Wikipedia, and the second is from San Francisco's Exploratorium:


Thanks for the explanation. I want to buy a telescope, not only to observe a solar eclipse . You are using a model of "Celestron 8 Inch CPC Schmidt-Cassegrain Telescope?" Is it possible for such a model using the camera mounting?


For the transit of Mercury of 1999 November 15, I used a Celestron 8 with a full-aperture solar filter and a Canon FTb SLR film camera at the prime focus. I had purchased telescope accessories, i.e., a prime focus adapter for the telescope and a T-adapter for the Canon camera.

Since then, the world, it seems, has gone to digital SLRs. I myself have two digital "point and shoot" cameras, but have not yet purchased a digital SLR to use with my Celestron telescope. So I cannot recommend how to proceed based upon recent past experience.

Nevertheless, I would like to say that both Meade and Celestron offer some really nice Schmidt-Cassegrain telescopes, for which you can buy accessories that will help you to do prime focus astrophotography using a digital SLR camera. Of course the two top camera brands would be Canon and Nikon. Both offer digital SLRs for which adapters are surely available for both the Meade and Celestron lines of telescopes.

It would be interesting to see the captured photo from Celestron.

I'll try to find the photographic film images that I took, but it was more than twelve years ago. I do recall that, at the time, I did not think the photographic prints were in any way impressive.

Partly because it was a "grazing" transit and Mercury is so much smaller than the Sun -- see the second diagram at this link for a depiction of the situation:

But the experience itself was quite memorable. An unusually warm and sunny day for mid-November.


Thank you for all the comments.


You are quite welcome. This is what distinguished Canadian-American dynamical astronomer Simon Newcomb wrote more than a hundred years ago:

"The transits of Venus across the sun's disk are among the rarest phenomena in astronomy. For many centuries past and to come there will be a regular cycle, bringing about four transits in two hundred and forty-three years. The intervals between the transits are one hundred and five and a half years, eight years, one hundred and twenty-one and a half years, eight years, then one hundred and five and a half years again, and so on.

The dates of the last six transits and the two next to come are as follows:

1631, December 7, 1874, December 9,

1639, December 4, 1882, December 6,

1761, June 5, 2004, June 8,

1769, June 3, 2012, June 6.

It will be seen that no person now living is likely to see this phenomenon, as the next transit does not occur until 2004. Yet, the time when Venus will appear upon the disk on June 8 of that year can now be predicted for any point on earth's surface, within a minute or two." (Astronomy for Everybody, Garden City Publishing Company, New York, 1902.)

When Newcomb published these words in 1902, he ended by talking about the transit of Venus of 2004 that happened just eight years ago, which no one then living would ever live to see.

Now I repeat Newcomb's words, updated to 2012: after the transit of 2012 June 5-6, it is likely that no person now living will see the next pair of Venus transits, predicted to occur on 2117 December 11 and 2125 December 8.

This is interesting.

Hi Roger,

I know that this is an old topic, but could you then see the transit of Venus? That day in my city it was cloudy.

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