Astronomers prepare for 'Transit of Venus'

Planet will move in front of sun Tuesday evening

Peninsula residents will have the chance to see Venus travel in front of the sun on Tuesday, June 5 -- an event that won't occur again for more than 100 years.

The Peninsula Astronomical Society will hold viewings for the "Transit of Venus" at the Foothill College Observatory and at Vista Hill in Foothills Park. Free viewings at the two sites will run from 3:30 to 7 p.m. and 3 to 7:30 p.m., respectively.

The observatory is open to the public while Foothills Park is open to Palo Alto residents only.

People should only look at the sun using filters specifically designed for that purpose, and both viewing sites will have telescopes with white light and hydrogen alpha filters that allow for direct viewing of the sun.

Peninsula Astronomical Society board member William Phelps said Venus will look like a tiny black disc traveling across the sun.

Phelps will be at Vista Hill with his homemade hydrogen-alpha telescope, which is two meters long and weighs almost 400 pounds. Hydrogen-alpha telescopes view a very narrow portion of the light spectrum and allow people to see the chromosphere, the outermost layer of the sun where solar prominences and flares occur.

In a prominence, solar material leaves the sun's surface and returns, while flares eject material out into space.

"Sometimes it's a little scary ... because of the scale," Phelps said. "They're massive, huge amounts of energy. We've had several magnetic pulses from the sun shut down power grids."

According to the Peninsula Astronomical Society's website, astronomers in previous centuries used transits to help them calculate the distances between the sun and the Earth, known as Astronomical Units.

Pairs of Transits of Venus occur approximately every 100 years, with eight years separating the first and second events of the pair.

According to NASA's website, this transit will be viewable from all of North America.

But the last transit in 2004 wasn't visible on the West Coast, so Phelps traveled to the eastern tip of Long Island to view the event with other astronomers and astronomy enthusiasts.

"I got the prize for ... traveling the furthest," he said.

NASA will also be presenting a live webcast of the event.


Like this comment
Posted by Resident
a resident of Another Palo Alto neighborhood
on Jun 5, 2012 at 8:37 am

The Channel 7 meteorologist said last night to use binoculars to view this rather than the naked eye. I think she meant a telescope with filter. Do not use binoculars to look at the sun.

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Posted by William
a resident of Midtown
on Jun 5, 2012 at 9:29 am

Wow, Channel 7 said that? No, please DO NOT use binoculars to view this event unless you have proper solar filters. What you CAN do with binoculars is turn them around and project an image of the sun on something white - cover one side of the binoculars first. Limit the amount of time you do this to avoid damaging the binoculars.

Or just join us at either Vista Hill in Foothills Park or at the Foothill College Observatory, where we will have safe solar telescopes for you to look through.

William Phelps

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Posted by QUESTION
a resident of Downtown North
on Jun 5, 2012 at 11:15 am

Can one use a pin hole camera and watch it the same way we could during the eclipse the other week?

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Posted by musical
a resident of Palo Verde
on Jun 5, 2012 at 12:59 pm

A pinhole doesn't make a very big image unless the screen is far away, and then the image gets really dim, unless the pinhole is large, but a larger pinhole gives a blurrier image. No win situation, but try it anyway. I suspect Venus is too small to resolve with a pinhole.

Venus is barely big enough to see with your eyes through a filter unmagnified. Venus is really black, darker than any sunspot, so the contrast is great if you have good focus.

As William said, binoculars are best used (frontwards) to project an image out of the eyepiece onto a white piece of paper 2 or 3 feet away. More light and a bigger image than a pinhole. You'll need a steady hand or a tripod, and some playing around with the focus knob.

I myself have duck-taped the black plastic from official sun eclipse glasses over the front of my small cheap 10x25 binoculars to get a direct magnified view. You REALLY DON'T want the filter to slip off or your retina is toast. For telescope or binocs, the filter goes over the front, never at the eyepiece or you might see smoke from the concentrated sunlight, followed by burning eyeball.

Best bet for this once-in-a-lifetime event is to find experienced observers with the right equipment. The transit goes on for hours, so this is much less frenzied than the precious seconds of a total solar eclipse.

Sure hope the clouds abate.

Like this comment
Posted by Danielle
a resident of Old Palo Alto
on Jun 5, 2012 at 1:49 pm

using black plastic from official sun eclipse sunglasses with binoculars is not recommended, it will damage your eyes

it is not designed for use with magnifying devices such as binoculars or cameras

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Posted by William
a resident of Midtown
on Jun 6, 2012 at 10:50 am

My thanks to everyone who joined us on Vista Hill to view the transit - you were all great! The next star party on Vista Hill is June 23, hope to see you then.

Posted by Name hidden
a resident of Ohlone School

on Jun 6, 2017 at 9:30 am

Due to repeated violations of our Terms of Use, comments from this poster are automatically removed. Why?

Sorry, but further commenting on this topic has been closed.

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