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Messenger Venus flyby images
Gladstoner
post May 29 2015, 09:14 PM
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Regarding the few images released after the 6/5/2007 Messenger flyby of Venus:

http://photojournal.jpl.nasa.gov/catalog/PIA10124

The image caption states that 614 images were acquired. Are these available?

After all these missions, there is still a lack of (available) visible-light (non-UV) images of the 2nd rock.
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Bjorn Jonsson
post May 29 2015, 09:29 PM
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QUOTE (Gladstoner @ May 29 2015, 09:14 PM) *
Regarding the few images released after the 6/5/2007 Messenger flyby of Venus: http://photojournal.jpl.nasa.gov/catalog/PIA10124 The image caption states that 614 images were acquired. Are these available? After all these missions, there is still a lack of (available) visible-light (non-UV) images of the 2nd rock.


Yes, they are available - all of the Messenger images are released through the PDS imaging node: http://img.pds.nasa.gov/

Visible light images are (almost) completely featureless with the exception of violet images so they aren't that useful.
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Gladstoner
post May 30 2015, 12:54 AM
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QUOTE (Bjorn Jonsson @ May 29 2015, 04:29 PM) *
Yes, they are available - all of the Messenger images are released through the PDS imaging node: http://img.pds.nasa.gov/

Visible light images are (almost) completely featureless with the exception of violet images so they aren't that useful.


Thank you. Unfortunately, there doesn't appear to be any full-disk views there, unless a mosaic can be assembled from the close-ups.

In any case, I've always wanted a photo/image of Venus as our eyes would see it in person. I hope a future spacecraft using Venus for a gravity assist could snap a few photos.
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dvandorn
post May 30 2015, 01:07 AM
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The best one I've seen is this Mariner 10 attempt at a true-color image from its Venus flby. It was produced by Ricardo Nunes from Mariner's clear and blue filters.

Here's the URL for this and other Mariner 10 images by him:

Mariner 10 - 1973/75 - "Mission to Mercury and Venus"

Attached Image


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elakdawalla
post Jun 1 2015, 04:28 PM
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That version did not correct for the nonsquareness of the pixels, so looks oval (and yellow). I like this version of the Mariner 10 global by Mattias Malmer. Also, here is a color (yes, color) view of Venus from the MESSENGER flyby data, processed by Gordan Ugarkovic.


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4throck
post Jun 1 2015, 10:12 PM
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That orange version is some derivative of my original image.
The original shows a gibbous Venus (Mariner 10 doesn't have that much distortion, the camera system is similar to Voyager's) and colors closer to Malmer's version.



Mariner color data comes from Clear and Blue filters only.
I subtracted the Blue data from the Clear (panchromatic) channel, thus creating a synthetic yellow chanel.

Some interesting results also come from Venus Express ( http://www.astrosurf.com/nunes/explor/explor_vex.htm ):



I feel that all those images hold up quite well.
Some overall brightness and color variations are visible.
The general tone is yellowish, but it depends a lot on the actual processing, image gamma etc.


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Gladstoner
post Jun 2 2015, 02:48 AM
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Thanks everyone for the images and links. But this:

QUOTE (elakdawalla @ Jun 1 2015, 11:28 AM) *

is a gorgeous view of the planet. This isn't merely one of the many false-colored treatments and renderings I've seen throughout my life. This looks as if one is seeing Venus in person through a porthole in all its blank, yet spectacular and real glory. The understated appearance makes the planet even more mysterious and foreboding.

Too bad the globe doesn't fit within the frame. I may try to reconstruct the missing parts in a photo editor.
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ZLD
post Jun 2 2015, 05:16 AM
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Interesting. I hadn't seen that Messenger image myself. Had any comment been made about ground visibility with that image? Fascinating!

Attached Image


I also would like to note the interesting linear clouds towards the upper left of the dark region. Would be nice if that were smoke.

Here's the same image with the primary set to negative to provide a true color image showing the surface filtered through the cloud deck at the captured wavelengths, where those linear clouds are dark.



Edit: clarity


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4throck
post Jun 2 2015, 08:36 AM
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You can't see the surface in visual wavelengths.
The "atmospheric windows" are on the IR bands.

To view details on the clouds, simply use images on the UV band. Much better than trying to process visible images.

An interesting mission for that was Pioneer Venus.
I've tried to put together a small image library of full disk UV images:
http://www.astrosurf.com/nunes/explor/explor_pvenus.htm

On this case there might be some geometric distortion, since the "camera" was a Photopolarimeter, just like on P10 and P11.


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Phil Stooke
post Jun 2 2015, 05:07 PM
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As 4throck says, that image is not showing the surface.

If somebody wanted to convince me otherwise, I would want to know exactly which part of the planet was facing the spacecraft at that time. A general resemblance to one small feature is not nearly enough.

Sorry!

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tasp
post Jun 2 2015, 05:37 PM
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Very much appreciate the Messenger color Venus picture, Emily. The sharp edge of the limb emphasizes the featurelessness nature of the upper cloud deck very effectively. If there was something to see, it would be there.

Thanx very much for all your help here.
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JRehling
post Jun 2 2015, 06:31 PM
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Here's my best image of Venus, taken with a Celestron 6se last month:

Amateurs have turned up some very impressive results in UV and IR, but in visible light, there's not much difference between so-so, pretty good, and the best efforts.

I've played around with projecting this into a map, then projecting the map back into a sphere to create a full Venus image, but one has to make a good model with Hapke parameters to do that right. And then, you could get a nice full Venus image. Which, to spoil the surprise, is going to be a white circle. You may as well take a Voyager image of Uranus and desaturate the color away and you'll get almost the same result.
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4throck
post Jun 2 2015, 06:46 PM
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Nice image!

Again I agree. You can get good earth based images of Venus. Measure of quality is sharpness of the limb.
For that you should image when the planet is high, during the day :-)




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ZLD
post Jun 2 2015, 08:43 PM
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QUOTE (Phil Stooke @ Jun 2 2015, 11:07 AM) *
If somebody wanted to convince me otherwise


Not intending to be stuck on this but I do find the prominence of the lines interesting. I've never seen any other images of Venus with similarly sharp features present, beyond radar data. Does any one know what files this composite comes from in the PDS? It would be very helpful to know the time they were captured at least.

Also, my Venus geology is poor and when I previously notated Alta Regio, I intended Beta Regio. I'm not sure of the path that Messenger took past Venus, but if it was actually slightly above the ecliptic, and the shadowed limb is actually around the northern pole (as the clouds seem to allude to), the features could (and I emphasize that strongly in ignorance here) place the feature very near Beta Regio.


Click to animate


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JRehling
post Jun 2 2015, 10:13 PM
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Here, an amateur used IR to image Venus's night side. Whether or not surface features are visible, I'm not sure.

http://www.skyandtelescope.com/astronomy-n...venuss-surface/

Galileo used IR to map Venus topography - not leading to any useful improvements on the mapping of the planet, I don't think, but rather a nice demonstration that it's possible. Then Venus Express certainly improved on that work, collecting possible evidence of an active volcano.

http://sci.esa.int/venus-express/46816-sur...lcano-on-venus/
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