Venus is 41 arcseconds in diameter with a phase of 26 percent and at its greatest illuminated extent on December 6, 2002, 11:06 UT. 203 mm f/7 newtonian and Philips ToUcam Pro Webcam. This image was obtained near the beginning of morning twilight without an IR blocker. There is no hint of cloud features. 

    Venus is our sister planet. It is close to the Earth in size. However, it differs from earth in several important aspects. It has a bone-crushingly dense atmosphere that creates a runaway greenhouse affect raising the surface temperature to over 800 degrees F. It's surface is also obscured in visible light by an impenetrable haze of sulfuric acid.

    Curious dark markings in the cloud layer are visible in UV light. Imaging through a UV filter can bring out the rapidly changing pattern in the clouds. Venus rotates very slowly (retrograde), but the clouds make a complete circuit around the planet in about four days. The observation of Venus becomes more intriguing following speculation by some workers that the clouds of Venus harbor life (Life on Venus?). The clouds are certainly more hospitable than the surface. Within the clouds, temperatures and pressures are more similar to that of Earth's surface. It is possible that organisms have adapted to live in sulfuric acid droplets and may be responsible for the chemistry that creates the enigmatic dark markings.

  Venus is often close to the Sun and consequently difficult to observe in the night sky. It will be low in the morning preceeding sunrise or low in the evening following sunset through a thicker column of air. This increases the potential for atmospheric turbulence. Venus can be easily observed in the daytime when it is higher in the sky. Rayleigh scattering brightens the sky background and gives gives everything a blue cast (the sky is blue!). The proximity of the Sun can also increase the amount of scattered light. The heat of the Sun can heat up the tube and equipment increasing tube currents and electronic noise.

    Venus undergoes large variations in apparent size and marked phases as seen from Earth. At superior conjunction Venus is only about 10 arcseconds in diameter. At inferior conjunction, Venus attains a size of about 60 arcseconds in diameter, larger than the apparent diameter of any other planet.

August 30, 2003, 08:32 UT (14:32 MDT). Venus was captured at only 13 days after superior conjunction (August 18, 2003) and only 3.48 degrees in eastern elongation from the Sun. It is 99.8 percent illuminated, magnitude -3.9, and 9.7 arcseconds in diameter. More than half of the primary mirror was illuminated by direct sunlight when this image was obtained. Nevertheless, Venus was bright and plainly visible through the eyepiece despite the intense scattered light. 8" f/7 newtonian @ f/27 (Televue 2x barlow and extension tube) and Philips ToUcam Pro 740K webcam with Edmund IR block filter. !!! BE VERY CAREFUL WHEN VIEWING OBJECTS NEAR THE SUN!!!

December 22, 2000, 1:30 UT. 8" f/7 newtonian and PC-23C video camera with a Wratten #47 Violet filter and variable polarizer but no IR blocker. Venus is 19 arc seconds in diameter. 

October 27, 2002, just 4 days before inferior conjunction (the sun was a mere 8 degrees away in apparent angular separation). These images were each single shots obtained about noon with an 8" f/7 newtonian and a Nikon CoolPix 4500 digital camera using afocal projection through a 7.0 mm Televue Nagler eyepiece. 

  I consider myself a novice at imaging this planet but hope to concentrate more effort on it over the coming months. It is possible that I will detect some of the surface markings in visible light. I will use an IR blocker with the Philips ToUcam Pro 740K webcam to prevent infrared bleedthrough on its red and blue filters. I hope to record some cloud markings, especially in blue and ultraviolet wavelengths. 

Links

Venus

Association of Lunar and Planetary Observers (ALPO), Venus Section

British Astronomical Association, Mercury and Venus Section

Books