Re: [APML] A Different View of Venus' Atmosphere?

["Kevin Wigell" <kwemail@twcny.rr.com>]

Juan, thanks for the reply.

I was thinking that since Venus' atmosphere is considerably more dense than earth's, it would extend much farther from the surface. But examining your image more closely, I see the effect extends out probably several thousand kilometers from Venus. And I'm quite sure its atmosphere doesn't go out that far.

Congratulations again on an exquisite image.

Kevin Wigell

----- Original Message ----- 
From: <pleiades2004@pleiades-astrophoto.com>
To: "Kevin Wigell" <kwemail@twcny.rr.com>; "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Thursday, June 10, 2004 14:52
Subject: Re: [APML] A Different View of Venus' Atmosphere?


> Hi Kevin,
> 
> No, it is *not* the atmosphere what you're noticing on that image; it's
> actually a processing artifact. The problem with this image is a horrible
> bright ring around the Venus disk that appears when the image is processed
> to enhance structures at specific characteristic scales (wavelets, unsharp
> mask, etc.). The workaround to this problem is to remove the planet's disk
> (replacing it with something "neutral"), process the image, and then
> reinsert the disk with the help of masks. It's just the inverse problem to
> processing an image avoiding black rings around bright stars. The image
> shown is a quick processing, where we haven't done our best. We are
> reprocessing this image and soon we'll release a new version without the
> "pseudo-atmosphere" artifacts <g>.
> 
> We are indeed convinced that the bright arc shown on Jerry's image and ours:
> 
> http://pleiades-astrophoto.com/2004/venus_transit/venus_transit_2.en.html
> 
> *is* the atmosphere. I am processing more videos right now; let's see if
> this feature persists between the third and fourth contacts.
> 
> Regards,
> 
> Juan Conejero
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