{"id":907,"date":"2013-11-28T00:40:00","date_gmt":"2013-11-27T22:40:00","guid":{"rendered":"https:\/\/www.planetary-astronomy-and-imaging.com\/?p=907"},"modified":"2018-10-19T15:04:40","modified_gmt":"2018-10-19T13:04:40","slug":"image-surface-venus","status":"publish","type":"post","link":"https:\/\/www.planetary-astronomy-and-imaging.com\/en\/image-surface-venus\/","title":{"rendered":"Image the surface of Venus this winter!"},"content":{"rendered":"

One of the most fascinating planetary observation that you can make is imaging the surface of Venus, a planet however completely covered by a permanent layer of bright clouds. Or to say it better, you can image the thermal signal of the surface…<\/strong><\/em><\/p>\n

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Since the 80’s\/90’s and the work done at the Pic du Midi, we know that the thermal emission from the surface of Venus is visible from Earth. Its ground is heated at more than 400\u00b0C and emits an infrared signal around 1 micron, a wavelength barely accessible to amateur CCD’s. More over, the carbon dioxide gas (CO2) that makes 96 % of the Venusian atmosphere is translucent precisely around 1 micron! This thermal signal is then able to escape to space… At left is the best image I have obtained on 2004 May, 16th, with a C14 and an ATK-1HS.<\/p>\n

Of course this must be done on the night side… this is why you must wait for the phase to reach the crescent state.<\/p>\n

We are about to get two windows of imaging around the inferior conjunction of January 2014, in December and January-February of next year.<\/p>\n

It will be the last chance until 2015!<\/p>\n

When should you observe?<\/strong><\/span><\/h2>\n

You must take care of various parameters:<\/p>\n

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  1. The phase must be narrow enough for the surface to be seen, or the bright day-side crescent will saturate the whole image. A maximum phase would be around 20 %. The signal could be detected at more than 20 %, but at this value and under we are going to see details as well.<\/li>\n
  2. The planet must not be too low. An altitude of 10\/15\u00b0 is fine but it will still be observable below (with the amateur equipment, the observation must be done after sunset).<\/li>\n
  3. Above all… The Sun must be at least at 5\u00b0 below the horizon, or the sky background will remain too bright. You can find the altitude of the Sun for your location with WinJupos.<\/li>\n<\/ol>\n

    With all of this you have two chance to be successful:<\/p>\n