Now things are going to get more exciting. Venera 9 was the first mission to land on Venus with a camera and return images of the surface. Not so well known is that it was accompanied by an orbiter which imaged the clouds with a scanning camera (related to those tested on Lunas 19 and 22). If you want to understand Soviet planetary images you have to see Don Mitchell's site:
http://mentallandscape.com/C_CatalogVenus.htm
But no peeking ahead to other missions...
#venus
I'll let you digest what Mitchell gives us for Venera 9, and tomorrow we will look at the landing site.
I had big plans to map the Venera landing sites but I didn't get very far with it before Mars took over my life. But I will post whatever I can find in my old files.
#venus
The link I posted earlier shows the Venera 9 panorama - here is the image in its raw form:
http://mentallandscape.com/C_Venera09.jpg
Don Mitchell explains how it was taken. A scanner runs from left to right across the scene, looking out at the horizon at left and right but down at the foreground in the middle (like the Luna 20 panorama we looked at a while ago). Then it ran back across the scene in the other direction for about 60% of a second panorama. It fills gaps in the first version.
#venus #venera9
This view on Don Mitchell's page shows how the original pan has many gaps (during which other telemetry was transmitted), how some of them can be patched from the second pan, and finally how the remaining gaps can be patched by interpolating. That's to make it look good, it doesn't add any new data. And that end of the pan was very broken up so you have to be careful about interpreting that part of the image.
... but when Magellan images became available they attracted more attention:
https://www.hou.usra.edu/meetings/lpsc2016/pdf/2094.pdf
(similar content, slightly more condensed URL)
If I continued with my Venus atlas project I would certainly have been mapping this stuff, but it's not going to happen.
Tomorrow it's time to move on the Venera 10.
#venus #venera9
OK, what did Venera 10 see? This is the link I gave earlier to Don Mitchell's page about Venus images:
http://mentallandscape.com/C_CatalogVenus.htm
and here is the raw Venera 10 image:
http://mentallandscape.com/C_Venera10.jpg
His expert processing gives us this:
http://mentallandscape.com/C_Venera10_Processed.jpg
(raw, gaps filled from second image, remaining gaps filled by interpolation)
Both of these Venera landers carried a second camera on the opposite side of the lander, but in each case it failed to operate.
#venus #venera10
We have seen the Venera 9 and 10 panoramas, but take a look at this from the Planetary Society:
https://www.planetary.org/space-images/rectified-vs-original-venera-9-and-10-panoramas
(presented without any explanation on that page). This version has more detail:
https://www.planetary.org/space-images/standing-on-venus-with-venera-10
These are artistic re-workings of the panoramas, rearranging bits of the images to create a more understandable view. I show them because they pop up in image searches and are often misrepresented as original images.
#venus #venera10
Around the time of Veneras 9 and 10, Earth-based radar mapping was improving. This map is a composite of two radar datasets from this period, reprojected to the azimuthal projection I always use for global maps.
One paper was this:
Campbell, D.B. and Burns, B.A., 1980. Earth‐based radar imagery of Venus. Journal of Geophysical Research: Space Physics, 85(A13), pp.8271-8281.
The other... I think it was in Geophys. Res. Lett. but I haven't tracked it down yet.
#venus #radar
The next mission to launch to Venus was NASA's Pioneer Venus mission, with two components. Here is a NASA look back on its 40th anniversary:
https://www.nasa.gov/centers-and-facilities/ames/40-years-ago-pioneers-encounter-venus/
The mission consisted of an orbiter and a multiprobe carrier, launched separately. We will deal with the orbiter first, then look at the probe mission. The image is one of many taken by the orbiter, and here are several more:
https://commons.wikimedia.org/wiki/Category:Photos_by_Pioneer_Venus_1
This link:
https://www.lpi.usra.edu/resources/venus_maps/
gives you lots of Venus maps by USGS, but for today we want the top one:
https://www.lpi.usra.edu/resources/venus_maps/1324/I-1324_150.jpg
The map in the previous post was hard to read but this is much clearer. There are 2 obvious continent-scale highland areas (remember Venus is about as big as Earth) Earth. 10 degrees of latitude or along the equator is approx. 1000 km for scale. The poles were not mapped, but our modern view of the planet is becoming clear.
#venus #pioneervenus
While the Veneras were flying, Earth-based radar continued to probe Venus. Here are some radar results from the 1980s. The top image is radar reflectivity - bright is reflective, and it is rough terrain. The resolution is improving. Look at Myletta Fluctus (fluctus = flow), a vast lava flow, about 750 km end to end. The other bright features are tectonic ridges and fractures. Venus has been a geologically active world, most likely it still is.
The other images? That's a new story.
#venus
This link goes to my first Venus mapping abstract at LPSC:
I was still a near-beginner at geological mapping and at interpreting radar images, but I think it still looks reasonable now. The map covers all the Goldstone images available at the time (1988, I was still a grad student). I mis-spelled Eistla in 2 different ways! Oh well...
Here is another abstract from 1991 with a version of the map extended by using other radar images:
This is a more complex argument and I'm going to look at it more closely later. Basically, before this two authors had published a hypothesis about Aphrodite being a spreading ridge like those we see on Earth's ocean floors. It had an axis of symmetry which was offset by faults at right angles to the axis. It looked like a reasonable idea... but...
#venus #radar
Venera 13 had 2 cameras and both worked this time, giving 2 panoramas facing in opposite directions. As usual Don Mitchell gives us an excellent treatment of these panoramas:
http://mentallandscape.com/C_CatalogVenus.htm
(about 40% of the way down the page). The scene was scanned through 3 filters plus a clear filter so we have RGB images, nearly complete for one camera, only partial for the other. Here's one of them from that site:
Once you have those panoramas you can do some other things with them. Each one sees the horizon at each end and the foreground in the middle, so they can be projected into a sort of cylindrical projection which straightens the horizon. Here are the two Venera 13 panoramas.
Phil Stooke
Bill, organizer of stuff