Venus in 2002

See this diagram to see how these pictures relate to the orbit of Venus in 2002.

23 Apr 2002

Venus; 23 Apr 2002, 21:04 to 21:06BST (20:04 to 20:06UT) Venus is on the far side of its orbit so presents nothing more than a small, but extremely, bright white disk. The planet is essentially featureless but a gibbous phase of 91% (like the moon 3 days before full) is evident. The Sun shines from the left in this view (north is down and west is left according to astronomical convention) so some of the dark side is visible to the right. The red and blue colours should be ignored as they are a combination of refraction in the Earth's atmosphere and poor optical alignment in the telescope (I will have to see to this!). Minolta Dimage 7, 48.8mm, afocal projection using 25mm eyepiece on 8.75inch f/7.3 Newtonian telescope. 1/250s @ f/14, running at ISO400. Scale of 0.3 arc second (= approx. 370km) per pixel. 6 pictures stacked with Astrostack v0.9 using Mean mode.

7 May 2002

Venus; 7 May 2002, 20:53 to 20:56BST (19:53 to 19:56UT) A much clearer view of Venus: atmospheric conditions were better than on 23rd April, and I could also obtain more pictures to work with. The Sun shines from the left and the gibbous phase of 88% (i.e. 12% of the dark side showing) is very clear. Venus still lies beyond the Sun, at 215 million km. The top picture shows the planet essentially as it appears in a telescope, a featureless, slightly yellowish white disk. Visually it appears very bright so I have kept the exposures short to prevent the image being overwhelmed with light as the eye tends to be. The lower picture is the same image but with an unsharp mask more strongly applied to highlight any features in Venus' cloudy atmosphere. The red and blue colouration on the top and bottom edge of the planet should be ignored as they are artifacts from the telescope-camera system. Minolta Dimage 7, 49.1mm, afocal projection using 25mm eyepiece on 8.75inch f/7.3 Newtonian telescope. 1/250s @ f/14, running at ISO200. Scale of 0.3 arc second (= approx. 340km) per pixel. 16 pictures stacked with Astrostack v0.9 using Mean mode.

1 Jun 2002

Venus; 1 Jun 2002, 20:20 to 20:24BST (19:20 to 19:24UT) Venus is now nearer compared to the last picture (at 195 million km) so appears slightly larger and has more of the dark side turned towards us. The phase is now 81%, i.e. 19% of the dark side is showing. Atmospheric seeing conditions were quite good as I managed to locate Venus about 3/4 hr before sunset, while it was still at a reasonable altitude of about 30 degrees. Venus is so bright that even though it was broad daylight, no blue sky can be seen at all in these composite shots, though it appears in the 27 originals as a dark blue background. Some of the original pictures indicated a dark feature on the terminator (night / day boundary) near the south pole. I have selectively processed these 8 shots to make the lower picture, where a small dark patch can be seen to the upper right. The blotchiness of the centre of the planet is an artifact of the deconvolution (sharpening) process, and indicates just how difficult it is to see any features on the cloud covered planet. Minolta Dimage 7, 49.1mm, afocal projection using 25mm eyepiece on 8.75inch f/7.3 Newtonian telescope. 1/250s @ f/14, running at ISO200. Scale of 0.3 arc second (= approx. 295km) per pixel. 27 (8) pictures stacked with Astrostack v0.9 using Mean mode.

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