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Home Forums Observing and Imaging Group Venus Take 2 23/04/15

This topic contains 3 replies, has 2 voices, and was last updated by  Mike Meynell 2 years, 5 months ago.

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  • #10930

    Astrograph
    Participant
    Topics: 27
    Replies: 101

    Made a few changes to the filtering and post processing and managed to get some cloud definition and a better colour reproduction. Mind you, I’ve never been to Venus so it could be bright orange for all I know.

    Venus 2 by astrograph ltd[/url], on Flickr

    • This topic was modified 2 years, 5 months ago by  Astrograph.
    • This topic was modified 2 years, 5 months ago by  Astrograph.
    #10933

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 749

    Are you sure you weren’t mistakenly pointed at Mars 😉

    Seriously, though… that’s a stunning image… cloud definition is fabulous. What filters did you use?

    #10934

    Astrograph
    Participant
    Topics: 27
    Replies: 101

    Thanks Mike

    Are you having a go at my colour balance? Just for you I have done a colour sample from an ESA image!

    Venus 2 false colour by astrograph ltd[/url], on Flickr

    Image was first adjusted visually with an ADC at 450x. I then used an Astronomik IR642 to give me a base image for the Red channel. That was featureless.

    For the Blue channel I used a Wratten No 47 filter in combination with a UV/IR cut filter. This is because a #47 passes IR in addition to UV from about 350nm up to about 450nm. An Astronomik UV/IR cut deals with the IR and does not cut UV until 350nm. As the clouds are only visible at the UV wavelengths, it is important to have a fairly tight bandpass around the UV area to get the best contrast.

    I do have an Astrodon ‘UVenus’ filter which only passes light in the 3-400nm band. Unfortunately, it renders Venus so dark at the f24 I was using it was not usable. The #47 keeps things relatively bright.

    This was only a 2 minute exposure (about 15000 frames). As Venus rotates very slowly, I may well try again near elongation with double or triple the exposure to try and bring out the clouds in more detail.

     

    #10935

    Mike Meynell
    Moderator
    Topics: 119
    Replies: 749

    Are you having a go at my colour balance? Just for you I have done a colour sample from an ESA image!

    Ah yes, this is more aesthetically pleasing to my eye!

    Interesting about the tight bandpass around the UV area… makes a lot of sense. Very impressed with the amount of detail you’ve been able to pick up using this method.

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