The Transit of Venus - 8 June 2004

Gallery of Masterpieces

The transit of Venus of 8 June 2004

For the first time since 1882, many amateurs could observe and picture the transit of Venus in front of the Sun. Imagine that nobody on Earth had the chance to observe this event for 122 years !

This time Europe was at the first place to observe this event with a sky clear to parly cloudy in most area with temperatures over 20°C. Venus was at 43.1 millions km from the Earth at 0.288 AU only, showing a disk 5 times larger that the one of Mercury and twice as larger as the one of Mars at perihelic opposition, with an angular diameter of 57.7".

In the United States conversely, amateurs could only see the end of the transit because the event had already began several hours before the sunrise. As far as the weather conditions are concerned, in the early morning hours most photographs were recordeds under a misty sky or partially cloudy, invaded with cumulus and stratus.

Although the seeing conditions in the United States where not at all favorable for this kind of spectacle, some amateurs didn't hesitate to go out with their apochromatic refractor or their telelens to get some pictures of a great aesthetic value as show the three documents displayed below.

Venus Transit Animation

A 7.4 MB Mpeg simulation prepared by GSFC


Postcards from the States... At left, a general view of the Sun during the transit of Venus at 10h30 UT (5h30 EDT). Even naked eye, we could see the small black disk of Venus in front of the Sun. This very fine picture was taken by Abe Megahed from Olin Park in Madison, WI, with a reflex body Nikon D70 equipped with a 70 mm telelens. Inserts have been recorded with a 8" SCT and a Nikon Coolpix 450 digicam by 11h UT. At center a picture taken at third contact at 11h10 UT (6h10 CDT) by Steve Sprengel from Lincoln in Nebraska, with a reflex body Canon 300D equipped with a Tamron 28-300 XR-LD telelens. Exposure 1/800th sec. No solar filter was necessary in this morning hour. At right, even under bad conditions and with low cloud, this dramatic view of the Sun taken at 10h35 UT confirms that it is always possible to get pictures of great aesthetic value. It was taken by David Cortner at prime focus of an Astro-Physics 130 mm f/6 refractor equipped with a Nikon D100. Exposure 1/3200th at 200 ISO, without solar filter. The location was along the Catawba river near Connelly's Springs, NC. Keep up the excellent job, guys !

The equipement

Let's see now what kind of material used amateurs to record this event. Clubs and groups of amateurs often used optics from 50 to 300 mm wide with an ocular projection on a screen and thus without solar filter. When they worked alone, most amateurs used a solar filter offering a transmission lower than 1/1000th (optical density from 3 to 5), adjusted to the diameter of their objective or off-centered, sometimes simply attached with a rubber band when it was a simple flexible sheet.

Many isolated amateurs used small achromatic refractors (doublets) like Orion ST-80 ED, Tele Vue Pronto 76 or 85 equipped with an objective solar filter.

At my great astonishment, among my close friends not less than five advanced amateurs used these small scopes, either fixed on a simple tripod or on an equatorial mount or fixed in piggyback on larger telescopes that, for once, were used as guider.

Some lucky amateurs didn't hesitate to go out with their "bazooka", I mean their Astro-Physics, Pentax, Takahashi or Zeiss apochromatic refractor from 100 to 155 mm of diameter, their Newton-Cassegrain or their Schmidt-Cassegrain scope of 200 mm or 317 mm (8-12.5") of diameter.

Among the accessories used in this special occasion, let's quote the sun glasses protected with a polymer film, a Mylar sheet or a Baader AstroSolar film made of alumined polyester, the full-aperture metal-coated glass filter up to 250 mm in diameter (e.g. Orion Telescopes or Thousand Oaks Optical 2+), the Coronado or Daystar H-alpha interferential filter, the Herschel wedge, the 1.8 and 2x Barlow lens and long focal eyepieces (32 to 12 mm).

At left Math Heijen and his friends preparing the observation of the transit from Holland. The TAL 200K Klevtzov-Cassegrain, the Celestron "Comet cachter" 114 mm f/3.2, the binoculars and the camcorder are all protected with a Baader AstroSolar filter. At right a terrestrial refractor 60 mm wide equipped with a 8 mm eyepiece (60x) projecting the Sun image on a screen at 9h15 UT. This technique used by Tim Smith from Crawley, West Sussex, U.K., allows to several observers to follow the event with modest means.

Among the cameras used, for close-ups all amateurs choosed a digital model, from the small Casio Exilm EX-S2 to the Nikon D1X reflex via the Philips Vesta Pro webcam and the Panasonic NC-DS15 camcorder.

About the coupling between the ocular system and the digicam, if most amateurs used a special T-ring suited to their body and worked at prime focus of their scope or by ocular projection with an extension ring, in several cases the objective of the digicam, the webcam or the camcorder could not be removed. In this case they worked afocal, placing the eyepiece or the ocular system close to the lens of their digicam, focusing to the infinite when possible and setting the optical zoom mode to the maximum (x3 to x10).

They were some accidents without gravity like this amateur, although it was well informed, who saw his solar filter screwed on his eyepiece be broken under the Sun heat (this solution is disadvised for this reason), this other who noted that his Mylar filter was full of pinholes and who had in a hurry to block out all the prick holes with a fine point felt marker and black paint (hence the interest to buy a quality solar filter) to avoid parasitic glare or this other amateur who crashed his CCD camera and had to fall back on his digicam.

Our preparations being finished and the transit being about to start, let's see some among the most beautiful images recorded during this event which, should it be pointed out, will not reproduce again before June 6, 2012. If you missed this one, do already book the next event because dame Nature will not offer you a third chance.

To be complete let's remind that on June 6, 2012 only observers living in the time zones +7 to +12h GMT (Russia-China-Philippines-Australia-New Zealand) might follow the entire transit of Venus. This time Venus will pass in front of the higher part of the Sun as indicated above (the time indicates the greatest transit).

In Europe, the Sun rising only around 4h UT, in Berlin or London the observers will only see the end of the transit (3^rd and 4^th contact) which will have already begun in the U.S.A. by 22h UT. In Europe the Sun will be only at 14 or 6° above l'horizon at the time of the 3^rd contact. Conversely in New-York or Los Angeles amateurs will only assist to the first phase of the transit (1^st and 2^nd contacts) a few times before the sunset. Up to you to get pictures as aesthetic as those recorded in 2004. So, the best locations to observe this phenomenon will be along the beach, over the eastern (Europe) or western (U.S.A) horizon.

The event of the century

At the first look through the eyepiece, all amateurs where surprised by the size of Venus (we all have in mind the minuscule disk of Mercury) but still more by the sharpness of the disk, like cut with a knife. Indeed, we are used to see its crescent which is a bit fuzzy.

Thanks to eclipse glasses, even naked eye we could see the small black disk of Venus in front of the Sun. Definitely this event had to be spectacular, and it confimed our foreboding all along its evolution.

Animations of the transit of Venus of June 8, 2004 around the second (5h40 UT) and third (11h04 UT) contacts. Both sequences were recorded from CAST Observatory located at Talmassons in north Italy by Roland Ligustri and Lucio Furlanetto using a SCT Celestron C11 equipped with a Nikon Coolpix 4300 digicam in zoom mode 3x. Exposure 1/250th sec. under an AstroSolar filter. The left sequence extents from 05h20 to 05h42 UT, the right one from 11h00 to 11h20 UT. Clic on images to run the animated GIF (494 KB and 732 KB).

The black drop effect and the halo

Among the "side effects" that we were all waiting for since 1882, note the "black drop" effect at the instant of the 2^d and 3^d contact more or less visible on three of the next images (Ayiomamitis, Bishop and Chrisman) and the arc of light or halo in the atmosphere of Venus in three images recorded before the 2^d contact and after the 3^d contact (Comolli, Smaal and Seip). This effet lasted 20 minutes according the observation made by Lorenzo Comolli using a 200 mm (8") SCT.

Both phenomena were already noticed by James Cook and Charles Green during an expedition in Tahiti in 1769 as displayed on the sketch at left, by the australian astronomer Henry Chamberlain Russell in 1874 and by the French astronomer Camille Flammarion in 1882.

Usually one told that the "black drop" effect becomes hard to see in scopes over 150 mm (6") of aperture but this time at least two american observers members of the Warren Astronomical Society, and using scopes of 250 mm f/10 (10") and 317 mm f/17 (12.5") observed it as shows very well the last picture at the end of this page. It was taken by Vince when the Sun was only 20° over the horizon, the scope tracking on Venus to get a stable image. But what is the origin of this strange effect ?

According Tom Van Flandern from META Research Institute, "the black drop effect is caused by variable refraction from moving air cells in the Earth's atmosphere".

Bradley Schaefer^[1] states that "the ideal image...will suffer smearing...that will produce a somewhat fuzzy image with contour lines (i.e., what is perceived as the edge) that are shaped like the Black Drop. The primary causes of smearing are the usual astronomical seeing (associated with small angle scattering in our Earth's atmosphere) and the usual diffraction in the telescope (the Airy pattern). Other contributing smearing mechanisms that generally do not dominate are imperfections in the telescope's optics, imperfections in the observer's eyes, the finite angular resolution of the detector, and even the physical size of the telescope's aperture".

So for short, the "black drop" effect is first of all depending of the height of the Sun above the horizon (seeing), then of the diffraction effect, while the instrumental resolution, and thus the aperture of the scope comes far behind. Its 's good to know.

Here are the pictures. All images displayed below have been inverted, displaying the north at top and the west to the right, like observing the Sun naked eye. The chronology of events was also respected.

Author: Johannes Schedler Scope: TMB 105 mm f/7 refractor on MK-100 GEM mount Accessory: Astro-Physics Barlow 2x, additional Barlow 2x (f/30) Filter: Baader AstroSolar film ND 3.5 Digicam: Reflex Canon 10D Exposure: Composite of 8 images at 1/3000th sec each, 100 ISO Image processing: PhotoShop Location: Wildon, Austria Date: 8 June 2004, 05:10-11:25 UT
Author: Observatoire de Besançon Scope: Tele Vue 76 f/6.3 refractor Filter: H-alpha Coronado SolarMax60 Webcam: Philips Vesta Pro B/W, RAW mode Image processing: none Location: Besançon, France Date: 8 June 2004, 05h19m21.1s UT
Author: Lorenzo Comolli Scope: Meade SCT LX 200 8"f/10 on Gemini G-41 mount Eyepiece: 40 mm and afocal coupling with camcorder Filter: AstroSolar ND3 CCD: Panasonic NC-DS15 camcorder Exposure: Mean of 2x 10-sec film, 1/2000th (disk) and 1/50th (halo) each Image processing: Iris, unsharp masking in PhotoShop Location: Tradate (Milano), Italy Date: 8 June 2004, 5h34 UT
Author: Anthony Ayiomamitis Scope: Tele Vue 70 mm ED Pronto refractor Accessory: Coronado CEMAX 2x Barlow Filter: H-alpha Coronado SolarMax60, BF10, and T-Max Tuner Digicam: Reflex Canon EOS 300D Exposure: Composite of 10 images at 1/50th each, 800 ISO Image processing: Canon FileViewer, PhotoShop Location: Athens, Greece Date: 8 June 2004, 08h22 UT and 05h39 UT for the insert
Author: Marco Cosmacini and Marzia Muradore Scope: Pentax 125 mm f/108 SDP refractor Filter: H-alpha Daystar ATM 0.6 Å Film: Kodak Elite Chrome, 100 ISO Exposure: Composite of 2 images, 1/60th (disk) and 1/15th (prominence) Image processing: Photoshop Location: Udine, Italy Date: 8 June 2004, 05h56 UT
Author: Jean-Louis Badin Scope: Zeiss 100 mm f/10 AS refractor Filter: H-alpha Coronado SolarMax90, BF15 and T-Max Tuner Webcam: Philips ToUCam Pro B/W, RAW mode, 10 images/sec Exposure: Composite, 50x 1/250th (disk) and 15x 1/250th (prominence) Image processing: Iris (bestof), Photoshop Location: Noisy le Grand, France Date: 8 June 2004, 9h50 UT
Author: Dominique Dierick Scope: Astro-Physics 105 mm f/6 Traveler refractor on AP900 GTO mount Accessory: Tele Vue Powerate 1.8x Filter: H-alpha Coronado SolarMax60 CCD: SXV-H9 Exposure: Composite of about 40 H-alpha images Location: Ghent, Belgium Date: 8 June 2004, 10h UT
Author: Tomas Maruska Scope: Rubinar 500 mm f/5.6 telelens Guiding: Newton 100/900 on Vixen GP-DX mount Filter: Baader AstroSolar film Webcam: Philips ToUcam Pro Exposure: 1/10000th at 30 images/sec Image processing: video image converted in Divx5 Location: Stupava, Slovakia Date: 8 June 2004, 10h09m17s UT Note : ISS (412 km of altitude) is crossing the field !
Author: Thierry Lombry Scope: Orion 80 mm f/7.5 ED refractor Eyepiece: Tele Vue zoom 8-24 mm (12 mm) Filter: Polymer solar filter Digicam: Canon PowerShot S30, afocal coupling Exposure: 1/50th, 100 ISO, zoom 3x Location: Brussels Date: 8 June 2004, 10h48 UT and 11h06 UT for the insert
Author: Paolo R. Lazzarotti Scope: Astro-Physics 130 mm f/6 refractor Accessory: APO Barlow 2x Filter: none, Herschel wedge, white light (R+IR bands) CCD: Webcam Philips Vesta Pro B/W Exposure: Composite of 150 images at 1/100th each Image processing: colorized by the author Location: La Spezia, Italy Date: 8 June 2004, 10h54 UT
Author: Phil Bishop Scope: TMB 115 mm f/7 refractor Accessory: 1.4x teleconverter Filter: none, Intes Herschel wedge Digicam: Reflex Nikon D1X Exposure: 1/600th, 200 ISO Image processing: PhotoShop Location: District A.S. Observatory, Letchworth, UK. Date: 8 June 2004, 11h03 UT
Author: Dominique Dierick Scope: Astro-Physics 105 mm f/6 Traveler refractor on AP900 GTO mount Accessory: 1.8x Tele Vue Barlow Filter: H-alpha Coronado SolarMax60 CCD: SXV-H9 Image processing: colorized by the author Location: Ghent, Belgium Date: 8 June 2004, 11h03 UT NB. This image was exposed for the prominences, but this "drop effect" of Venus came out as well. It is present on all images, so it's definitely not a seeing effect but rather an artefact (bleeding). Visually, nothing of this kind was seen either. So be warned for 2012.
Author: Pete Lawrence Scope: Vixen 102 mm f/9 FL refractor on GPDX mount Eyepiece: 32 mm Kellner, afocal coupling with digicam Filter: Baader AstroSolar film Digicam: Olympus C2100UZ, 10x zoom (set on 70 mm f/3.5) Exposure: 1/1000th, 100 ISO Image processing: Photoshop and colorized Location: Selsey, West Sussex, UK Date: 8 June 2004, 11h04m11s UT
Author: Thierry Legault Scope: Takahashi 106 mm f/5 FSQ refractor, aperture 60 mm (f/20) Accessory: TV Powermate 1.8x and Meade focal reductor 0.33x Filter: H-alpha Daystar ATM 0.5 Å CCD: SBIG ST-10XE Exposure: 1/125th Image processing: Iris and Prism, colorized by the author Location: Roissy, France Date: 8 June 2004, 11h04 UT
Author: Jeroen Smaal Scope: Celestron SCT C8 f/10 on a Vixen Sphinx mount Eyepiece: 32 mm Plössl Filter: Metal coated glass solar filter Digicam: Nikon Coolpix 995 full zoomed Exposure: 1/200th, 100 ISO Location: Public Observatory of Rijswijk, Holland Date: 8 June 2004, 11h04 UT
Author: Stefan Seip Scope: Astro-Physics 155 mm f/7 refractor on AP900 QMD mount Accessory: Astro-Physics 2x Barlow Filter: Baader Herschel Wedge with gray filters (1000x, 64x, 8x) CCD: SBIG STL 11000XM with SBIG RGB filter wheel Exposure: Composite of 2 images under red filter, 0.05 and 1 sec Image processing: MaximDL, Photoshop, colorized by the author Location: Suttgart, Germany Date: 8 June 2004, 11h05m48s and 11h06m20s UT (shift 0.5")
Author: Pedro Re Scope: Takahashi 102 mm f/8 FS refractor Filter: Baader AstroSolar film Webcam: Philips ToUCam N/B Exposure: Sum of 100 best images Image processing: colorized by the author Location: Carvoeiro, Algarve, Portugal Date: 8 June 2004, 11h06m18s UT
Author: Vince Chrisman Scope: Meade SCT 10" LX200 GPS w/UHTC coating Eyepiece: 20 mm Meade Super Plössl Filter: Orion full-aperture glass solar filter (#07715) Digicam: Casio Exilm EX-S2 holded by hand, afocal coupling Exposure: Automatic Location: Sterling Heights, MI, USA Date: 8 June 2004, 11h07 UT (7:07 am EDT)