The Venus Transit 2004

... Photos by Themes

The "Black Drop" Phenomenon

The 'Black Drop' phenomenon

On this page, photos related to the so-called "Black Drop" phenomenon are displayed, as they were recorded during the Venus transit on June 8, 2004 and shown at the VT-2004 website. This effect is illustrated on the drawing to the left and has been known by observers since long. It implies that Venus appears to be "stuck" to the limb of the Sun near the moments of the second and third contacts, as if with some kind of chewing-gum. It makes it difficult to estimate the moment when the border of Venus' dark circle exactly touches the border of the Sun.

Details about this phenomenon were placed on a dedicated webpage, warning all observers to be careful when timing the contacts. However, the experience during this year's transit proved that it must have been mostly due to the lesser optical quality of the telescopes that were used to observe the transits in the XVIII and XIXth centuries.

In any case, as the photos on this page demonstrate, the "Black Drop" phenomenon obviously did not play any significant role this time. Many observers remarked that they did not suffer any particular difficulties with the timing and many image sequences (see below) testify to the general absence of such an effect. Look also at the special page in the VT-2004 Photo Archive that deals with image processing techniques on photos obtained near the moments of the contacts.

An overview of the VT-2004 Photo Archive is available and a number of these photos have been elected "VT 2004 Photo of the Day".

All photos on this page may be downloaded and used, provided the photographers (authors) and the VT-2004 programme are indicated as source.




Individual Photos Displaying the Varying Degrees of the "Black Drop" Effect




Venus Transit - 2nd Contact [640 x 480 pix - 92 Andjelko Glivar Celestron 102mm f/5 with 2x teleconverter Canon EOS 300D digital SLR camera [Black Drop?] More images at this site June 8, 2004 Croatia	Venus Transit - 2nd Contact [2900 x 1946 pix - 161k] Paolo Campai [Black Drop phenomenon visible] June 8, 2004, 07:39:50 UT Florence, Italy

Venus Transit - Second Contact [384 x 288 pix - 47k] Frederik Bove 10-inch Meade LX200 Mintron MTV-12v1 June 8, 2004 Belgium	Venus Transit (Black Drop) [604 x 564 pix - 25k] Statis Kalyvas 4.5-inch Mizar telescope Nikon Coolpix 750 June 8, 2004 Thessaloniki, Greece

Near 2nd Contact [800 x 640 pix - 38k] VT-2004 Team Slovak Union of Amateur Astronomers Observatory Rimavska Subota 160/2450mm refractor with AstroSolar filter CCD camera SHT June 8, 2004, 05:39:50 UT Rimavska Subota, Slovakia More images at this site	Venus Transit - Third Contact [384 x 288 pix - 50k] Frederik Bove 10-inch Meade LX200 Mintron MTV-12v1 June 8, 2004 Belgium

Venus at 3rd Contact (3) [320 x 240 pix - 42k] Daniel del Valle 8-inch Schmidt-Cassegrain telescope Logitech QuickCam ["Black Drop" phenomenon] June 8, 2004, 11:10 UT Aguadilla, Puerto Rico, USA	Near Third Contact [640 x 480 pix - 16k] Saverio Cammarata & Giuseppe Marino Gruppo Astrofili Catanesi Webcam Philips Toucam Pro and Schmidt-Cassegrain 25 cm telescope. Median of 40 frames. June 8, 2004 Catanese, Italy

Third Contact [800 x 640 pix - 18k] VT-2004 Team Slovak Union of Amateur Astronomers Observatory Rimavska Subota 160/2450mm refractor with AstroSolar filter CCD camera SHT June 8, 2004, 11:03:40 UT Rimavska Subota, Slovakia More images at this site





Photo Sequences Near Second Contact





Venus Transit - The Beginning [512 x 1024 pix - 22k] Robert Fosbury ST/ECF - ESO HQ 3-inch refractor Sony DSC-F717 June 8, 2004 Ottobrunn near Munich, Germany	Venus Transit (Ingress) [1300 x 975 pix - 110k] Elio Daniele Gruppo Astrofili O.R.S.A. Apochrom. refractor Tele Vue NP101 550mm - f/5.4 with AstroSolar filter Nicon D100 Camera June 8, 2004 Palermo, Italy

Venus Transit (Composite) [900 x 823 pix - 197k] Domenico Licchelli Osservatorio del Fiorini Apo 75mm f/6.7 with 3 x Barlow TouCam Pro Exposure 1/250 and 1/1500 sec [Very poor seeing] May 20, 2004, 05:34:06 - 11:12:06 UT Lecce, Italy





Photo Sequences Near Third Contact




The Black Drop and Optical Resolution [406 x 606 pix - 77k] Herbert Raab Linzer Astronomische Gesellschaft 100-mm f/9 flourite refractor Solar Max 60 H-alpha filter Mintron 12V1C-EX B/W video camera [Images from the video sequence obtained at nearly the same moment, but with "bad" (left) and "good" (right) image sharpness are compared. It is clear that the "black drop" phenomenon is more pronounced in the "bad" images.] More images at this site June 8, 2004, 11:03 UT Linz, Austria	Third Contact at High Resolution [1500 x 554 pix - 73k] Ralf Vandebergh 6-inch refractor f/8 Sony TRV740 camcorder [All images are composites of several frames] June 8, 2004, 11:00 - 11:05 UT The Netherlands

Black Drop Development [408 x 1006 pix - 173k] Eric Walker Highlands Astronomical Society 114-mm reflector with 32-mm Plossl Nikon Coolpix 5700 June 8, 2004, 11:03:04 - 11:07:11 UT Culloden Moor near Inverness, Scotland, UK	Venus Exit [1200 x 960 - 106k] Elio Daniele & Salvo Careri Refractor Tele Vue NP101 550mm f5.4 Nikon D100, Astrosolar Filter June 8, 2004 Palermo, Italy Astronomy Club O.R.S.A.

Black Drop Effect [503 x 1300 pix - 41k] Mauro Auteri & Floriano Paglia G.V. Schiaparelli Astronomical Observatory, Varese, Italy SC 203mmm at f/10 + Webcam Toucam Pro. June 8, 2004 ; 11:02-11:04 UT	Venus Transit (Egress) [1300 x 975 pix - 100k] Elio Daniele Gruppo Astrofili O.R.S.A. Apochrom. refractor Tele Vue NP101 550mm - f/5.4 with AstroSolar filter Nicon D100 Camera June 8, 2004 Palermo, Italy

Venus Transit (Composite) [900 x 823 pix - 197k] Domenico Licchelli Osservatorio del Fiorini Apo 75mm f/6.7 with 3 x Barlow TouCam Pro Exposure 1/250 and 1/1500 sec [Very poor seeing] May 20, 2004, 05:34:06 - 11:12:06 UT Lecce, Italy	Venus Transit - Near Third Contact [1424 x 493 pix - 117k] Jamie Cooper June 8, 2004 Northampton, UK

Venus Transit (Egress) [320 x 240 pix Animated GIF - 383k] David Brown LX200 Meade telescope f/6.3 TuoCam June 8, 2004 Worth Matravers, England, UK More images at this site	Venus Transit - Black Drop Phenomenon [350 x 237 - 22k] Astronomical Observatory Sliven 100/1000mm Cassegrain telescope SFO80 filter Praktika camera June 8, 2004, 11:03:03 - 11:04:20 UT Sliven, Bulgaria [See images of the event here.]

Venus Transit - Egress [1280 x 1200 pix - 175k] Enrico Mariani Meade ETX90EC f/13.8 Webcam Vesta June 8, 2004 Tradata (VA), Italy




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