Tuesday, June 5, 2012

Venus Transit 2012

Big Brain Machine view of Venus Transit 2012 - All photos copyright Humanoido
TODAY: Using it's robotic refracting 60mm AT telescope, the electronic Big Brain machine has captured a rare event - the Transit of Venus across the face of the sun. 

A transit of Venus occurs when Venus passes directly between the sun and earth.  This alignment is very rare, coming in pairs that are eight years apart but separated by over a century.

This happens when Venus passes in between the orbits of the Sun and Earth. This digital preprocessing image was taken about one hour ago, on Wednesday June 6th, 2012 at 11:49 am local time from Taiwan. As the sun rose, clouds and overcast completely intervened. During the time span from 11 am on into the afternoon, it suddenly cleared to a beautiful blue sky and the best images were captured. Previous atmospheric studies indicated such a weather pattern clearing was likely, and this held true.

Venus Transit 2012 Full solar view
To be on the safe side so as not to completely miss the event, numerous images were initially shot through the clouds. (The next Transit of Venus occurs in 105 years.) The 1st shown photo employed an 8mm Brandon Orthoscopic ocular for a solar "eyepiece projection" method of imaging. Projection distance averaged about 12-inches and a SONY DSC-T10 was used in automatic EI setting and magnifying mode with the super Steady Shot engaged. The projected full disc view with the 24mm FL ocular averaged around 8-inches in diameter. The large black dot is the planet Venus and the background is the Sun. Although Venus was slowly traversing across the face of the Sun, this slow movement was only noticeable in the time lapsed photography. The full solar disk image was obtained with a 24mm FL Meade ocular. Several sunspot groupings are just visible along with granulation.

June 5th, 2012 sunspots
A solar sunspot study was made in full color on the previous day of June 5th, 2012 at 4:43:48 pm local time, using ISO125 at 1/400 F5.6 to identify the position of solar spots, test the imaging results, obtain satisfactory full disk image size and resolution, position enlarged disc views, and lock down the setup and imaging procedures. (see June 5th photo)
June 6th sunspots during the transit
Approximately nine sunspot groupings are seen.

Note: no solar filters were used and the telescope was not aperture stopped down, however, the water vapor content of the atmosphere was extremely heavy, creating a layer acting as a reflective filter. (Taiwan is an island surrounded by ocean.) The telescope was set up on top of a very tall skyscraper overlooking the city, on a very heavy and stable concrete perimeter which has unobstructed views of the horizon in all cardinal directions. The telescope's temperature was monitored to avoid overheating and damage to optical, metal and polymer parts, as the image was safely projected and three cameras were used.

The image was received by a standard size clipboard mount with an Advanced Agro Double A A4 Premium sheet of photographic print paper of 210 x 297mm size at 80gsm. A small breeze at that height made keeping things in one place challenging. At one time, the telescope shroud was blown off during a break in astro imaging.

The two additional cameras were a Canon and Apple iPhone. Changes in heat temperature made periodic refocusing necessary for the most successful image sharpness. Several times, the SONY camera overheated and failed. Actual ambient temperature was around 95 degrees and in the sun directly the temperature rose to at least 120 deg. F on upwards to oven-like heat. To avoid heat stroke, the imaging session was suspended before event completion.

Images were downloaded to a Mac computer and preprocessed with Apple iPhoto using Edit, Adjust, Exposure, Contrast, Definition, Sharpness and Rotate. About 140 images were captured with the Sony camera and a set with a Canon Ixus 100 IS. Apple iPhone 3G held four images, primarily as a backup plan in case the other images underwent some anomaly phenomenon.

1994 OTM Venus Transit article image
The most recent transit before 2012 occurred June 8, 2004, and the next upcoming transits are in December 10-11, 2117, and in December 2125. As an interesting note, in 1992, the first issue of Observatory Techniques Magazine ran an article about time travel to the Transit of Venus in 2004 (page 10). It included a computer generated image of Venus moving across the Sun which looks remarkably similar in position to the actual 2012 image shown above. The now rare collector's copy of the first OTM issue includes articles about computer image processing, telescope systems design, Saturn's rings, time conversions, hints & techniques, and the astronomer's vision. Although color ink issues are discontinued, OTM occasionally appears as a free online version or available through special offering.

Work is progressing to montage the motion of Venus across the face of the sun with the AT telescope and to utilize the Big Brain's new GT Telescope in space to study the nature of Venus' atmosphere as it filters solar radiation.

The Big Brain machine retains a complete image archive of the 2012 Venus Transit from two telescopes and three imaging cameras.