Phil StookeDec 20, 2024

Here is part of a CIA map of Libya - I'm using it because it's public domain. It comes from here:

https://loc.getarchive.net/media/libya

(A Library of Congress site with public domain maps. Can be a handy resource! The Schiaparelli map was from Wikimedia Commons.)

Surt, Sidra - they are forms of the latin name Syrtis, a marsh, and Syrtis Major was a large marshy area along the coast here. So it is a place on Earth like the others. Are all those names from Earth? #maps #Mars

Show threadPhil StookeDec 20, 2024
One more example which I won't illustrate - Look on Schiapareli's map a bit above (south of) Syrtis Major at the left side of the map. See Hellas? That's an easy one - it's Greece. So you get the idea - these Mars names are places on Earth and in particular they come from classical geography - a mixture of real places known to the Greeks and Romans and mythological places from those sources. In Schiaparelli's time any educated European knew these things. #maps #Mars
Show threadPhil StookeDec 20, 2024
So... the big question is - are these Schiaparelli names just randomly distributed or is there a pattern behind it? You guessed it - there's a pattern. That's where we are going next. #maps #Mars
Show threadPhil StookeDec 21, 2024
We need a bit of a mind-flip to understand how Schiaparelli developed his naming scheme. We start with a map of Mars - let's use a modern one from the Hubble Space Telescope. But Schiaparelli didn't see Mars like this... #maps #Mars #Hubble
Show threadPhil StookeDec 21, 2024
No - Schiaparelli saw Mars like this - with south at the top. Until the dawn of the space age most planetary maps were drawn with south at the top as seen in an inverting astronomical telescope. Only when maps might be used for direct physical exploration did the convention change to avoid potential confusion. Rather than turn our screens upside down, let's do a 'rotate 180 degrees' in Photoshop. Simples! #maps #Mars #Hubble
Show threadPhil StookeDec 21, 2024
Now we need to look back in time to the classical understanding of the world. How better to do that than with Ptolemy's map of the world known to him at the time? None of Ptolemy's maps survived into the medieval world, but his list of places - a sort of gazetteer - did. 8000 places with his estimates of their latitude and longitude, from which his maps have been reconstructed. See the similarity? No, nor do I, but Schiaparelli found a way to link them. #maps #Mars #Ptolemy
Show threadPhil StookeDec 22, 2024
This was how Schiaparelli related Ptolemy's Earth to Mars. The Greek Sun god, Helios, rode a chariot across the sky, rising in the far east of the world and passing over it during the day. At sunset he descended into the far west, moving by boat under or behind the world, back to the east for the next sunrise. So on Mars he would move over the planet, passing places named for regions he saw during his terrestrial daytime journey. #Mars #Helios
Show threadPhil StookeDec 22, 2024
This implies that the Martian names would begin with places from the far east of Ptolemy's map, and names would progress towards western places. Our names should be distributed like that. But where does the scheme start on Mars since there is no obvious place to begin? Schiaparelli found a perfect starting point. These are the traditional astronomical symbols for the Sun, Moon and planets. Schiaparelli found the Sun symbol on Mars. #Mars #astronomy
Show threadPhil StookeDec 22, 2024
And here it is. A Hubble image of Mars and a 19th Century drawing, both with south at the top. Astronomers had observed a roughly circular marking with a central dark spot. Schiaparelli made it the place where Helios would begin his journey over the planet, distributing names as he went. He named it Solis Lacus, the Lake of the Sun. The modern feature Solis Planum is inside it. #maps #Mars #Shiaparelli
Show threadPhil StookeDec 23, 2024
We will do a quick run along Helios's path looking at some basic names to establish the pattern. Then we can explore some interesting places. We start with Helios at Solis Lacus - not a specific place on Earth but somewhere at the easternmost end of Ptolemy's world. "And now the sun, leaving the beauteous mere, sprang up into the brazen heaven to give light to the immortals and to mortal men on the earth" (Homer: Odyssey, book 3, line 1)
#maps #Mars #Helios
Show threadPhil StookeDec 23, 2024
Moving west, we come to Chryse - the Golden Land - which is Thailand and home to Viking 1 and Pathfinder. Are we going west? Yes, on the terrestrial map. No, on Mars as we define east and west today, but east and west were reversed on those old astronomical maps. When the IAU flipped the maps from south-up to north-up they also flipped east and west to avoid confusion in the new world of direct exploration. That's why the Moon's Mare Orientale is on the western limb.
#maps #Mars
Show threadPhil StookeDec 23, 2024
Next on our journey we encounter Ganges. You can find it on Schiaparelli's map from a few days ago, just left of the middle. There it's a canal, and my arrow points to the place where the canal joins the dark 'land' of Aurorae Sinus (Dawn Bay). Now the name is used for a dramatic canyon, Ganges Chasma, with several spectacular landslides. It's part of the giant rift valley complex called Valles Marineris. #maps #Mars
Show threadPhil StookeDec 24, 2024
Moving right along - we come to Arabia. In this scheme dark areas on Mars are seas and bright areas are land, and indeed much of Arabia does look a bit like Mars from above. The modern Arabia Terra on Mars is a cratered upland area. #maps #Mars
Show threadPhil StookeDec 24, 2024
This one might not seem so obvious. Noachis on Mars is Turkey. Why? It's the land of Noah. In the story of the great flood, which was survived only by Noah, his family and two of every animal (a rather serious population bottleneck), Noah's Ark comes to rest on Mt. Ararat in Turkey as the waters subside. #maps #Mars
Show threadPhil StookeDec 24, 2024
Finally for today, one we have already seen, it's Syrtis Major. #maps #Moon
Show threadPhil StookeDec 31, 2024
Back to work! I will spend a few more days looking at Schiaparelli's Mars nomenclature before getting on with the Mars mapping sequence. Today, an obvious one: Hellas, which of course is Greece, north of the Syrtis Major where it should be. #maps #Mars
Show threadPhil StookeDec 31, 2024

Now we have a framework for Schiaparelli's names. Helios passes over places on both planets in turn, all very logical. Will it stay that way?

What about places at the right side of the Mars map? Tharsis, for instance. What about places that are not real places on Earth, like Elysium? And we have already seen two names (Syria and Sinai) which are placed on Mars beside Solis Lacus, the whole width of Asia away from their real locations. Don't expect full consistency! #maps #Mars

Show threadPhil StookeJan 1, 2025
Now for a quick run through some interesting names on Mars. Here is Hesperia - a rather nondescript place on Schiaparelli's map but important on modern Mars as a lava plain formed in the middle part of Mars history, the Hesperian period. On Earth it's either Spain or some Atlantic islands, usually equated with the Canary Islands, the Hesperides. Hesperus, the evening star, is connected too, related to sunset. #maps #Mars
Show threadPhil StookeJan 1, 2025
Elysium... it's not a real place unless you are enjoying a trip to Paris. It is supposed to be in the very far west, so its position out beyond the Mediterranean places, Greece and Syrtis Major, is not too inconsistent with this scheme. #maps #Mars
Show threadPhil StookeJan 1, 2025
I find this one particularly satisfying. Where is Tharsis on Earth? The vast volcanic province is so far west that it slipped around the end of the Mars map and appears on the right, not far from Solis Lacus. On Earth it's outside the Pillars of Hercules (look back at the Schiaparelli map to see the Pillars of Hercules named in Latin) - at Tartessus, the Rio Tinto area mined since antiquity and also an analog for the acidic waters of Meridiani Planum. Amazing how things tie together! #maps #Mars
Show threadPhil StookeJan 2, 2025
Now for a bit of Egyptology. Here are some names associated with the River Nile. They form a string of small dark markings near the northern end of Syrtis Major (bottom in this south-up map of Mars. The modern placenames are all clusters of hills and small plateau structures. #maps #Mars
Show threadPhil StookeJan 2, 2025
Another one not far from the Perseverance landing site in Jezero crater. Nili Fossae are a set of long, wide faulted valleys partially encircling Isidis Planitia and associated with the Isidis impact basin. The floor of one of the valleys was considered as a landing site for both Curiosity and Perseverance. #maps #Mars
Show threadPhil StookeJan 2, 2025
With all those Nile references, it should not come as a surprise that Egypt is here as well. Isidis - the land of Isis - is Egypt. The Egyptian deity Isis was adopted to form a widespread cult among Romans, reaching even to that distant outpost Britain. Isidis is an ancient impact basin filled with sediments. Every year in about 1985-1995, Heinz-Peter Jöns was a fixture at LPSC promoting the idea of aqueous sediments in Isidis, and eventually people caught up with him. #maps #Mars
Show threadPhil StookeJan 3, 2025
This one really does not fit the pattern. Acidalia is a dark area north of Chryse, where Viking 1 and Pathfinder landed. It's a smooth low-lying plain so its modern name is Acidalia Planitia. Its location on Mars should correspond with India (Ganges, which we saw earlier, is nearby), but actually Acidalia is in Greece. You can hardly expect an exact correspondence between the two planets. #maps #Mars
Show threadPhil StookeJan 3, 2025
Argyre is a large impact basin south of the Valles Marineris. The name refers to a legendary source of silver in or near Burma (AKA Myanmar). The longitudes fit Schiaparelli's scheme quite well. Latitudes, not so much. #maps #Mars
Show threadPhil StookeJan 3, 2025
Just to the west of Meridiani is Margaritifer Terra, Margaritifer Sinus in old maps. It's a place on Earth too, around the southern tip of India (not very well portrayed by Ptolemy), and it means the place of pearls. The region was famous for its pearls and still is.
Show threadPhil StookeJan 4, 2025
Today, the last 3 places in my Mars names story. We start with Arcadia, a poor rocky land in southern Greece where shepherds lived a hard life but were said by city folk to be carefree and innocent compared with the corrupt inhabitants of the cities. Poussin's painting shows shepherds reading an inscription on a tomb: Et in Arcadia Ego (roughly 'I (death) am also (or even) in Arcadia'. The line has become famous from Dan Brown's 'Da Vinci Code' and its curious precursors. #maps #Mars #Arcadia
Show threadPhil StookeJan 4, 2025
Next, Utopia, where Viking 2 landed in 1976. Unlike all those other names, this is not ancient and comes from Thomas More's book of 1516. It literally means 'nowhere' and is used for a perfect place or society (maybe so perfect it couldn't really exist). In the book it was an island out in the Atlantic near the Americas.This name is not on Schiaparelli's map and probably comes from Flammarion and Antoniadi's map of 1900. #maps #Mars
Show threadPhil StookeJan 4, 2025

Finally - Amazonis. The name makes us think of the Amazon in Brazil, but originally it was the name of a female warrior society whose tales crop up all over the place in classical contexts. Amazons fought on the side of Troy in the Trojan war and are usually associated with northern Turkey.

OK, enough names. Now we will return to our sequence of Mars maps. #maps #Mars

Show threadPhil StookeJan 5, 2025
After that rather long excursus into Martian nomenclature we return to the sequence of Mars maps. Looking back, we saw maps of light and dark markings, at first barely glimpsed through telescopes, but evolving into quite sophisticated drawings - Green's map is quite realistic though others seem more sketchy. Schiaparelli saw lines ('canali') and Proctor rendered them as rivers. From 1890 to about 1930 many maps showed canals, which we now discount. #maps #Mars
Show threadPhil StookeJan 5, 2025
In the middle of the 20th Century canals had fallen into disfavour. Typical maps of the 1950s, such as the International Astronomical Union (IAU) map drawn by Glauco de Mottoni y Palacios in 1957 as a key to official nomenclature, showed broad light and dark areas similar to Green's map. Here it is stripped of names (by cloning) and transformed to my common projection. Nothing suggesting topography or geology is visible. Don't be fooled by assertions that some people saw craters. #maps #Mars
Show threadPhil StookeJan 6, 2025

That last map was drawn in the year of Sputnik. Direct exploration by spacecraft was not far off, so NASA needed a new map. The job went to the US Army and Air Force, who both had large mapping agencies and were gearing up for Moon mapping. I will show the Air Force map. You can see it here:

https://www.lpi.usra.edu/resources/mars_maps/MEC-1/

Look at that - it has canals! So did the less aesthetically pleasing Army maps. It's a curious footnote of Mars mapping history. #maps #Mars

Show threadPhil StookeJan 6, 2025
Here I add my manipulated version of it for easier comparison with the others. Look at the original - it's north up, not south up. The old astronomical convention was dropped. Longitudes go from 0 to 180 east and west from the prime meridian (still using the 1840 version of zero longitude). Our familiar names are on display. Compare Syrtis Major's longitude here and on the previous map - this one is 10 degrees too far east. Oops! #maps #Mars
Show threadPhil StookeJan 6, 2025
I made this version of the map for early Mars exploration mapping in my first Mars atlas. But pretty soon the first spacecraft exploration of Mars began, and sure enough, new maps would be needed yet again... tomorrow!
Show threadPhil StookeJan 7, 2025
I mis-spoke there - we don't see a new map right now, but new things. This map, with the old Air Force map as a base, shows the locations of the Mariner 4 images taken in 1965. We take this for granted today but the idea that you could build a machine and send it to Mars, and get pictures of its surface back was unbelievably audacious at the time. There were a few extra frames but they crossed the terminator and showed nothing. How did I know where to put those images? #maps #Mars #Mariner4
Show threadPhil Stooke

I positioned the images like this. Using a modern map as a background, I matched each Mariner 4 image to surface features. At the time this was impossible, In fact the bright markings in the top image (frame 1) were thought to be clouds, but my comparison shows every one is a real surface feature. Compare with this contemporary map (this time on the US Army base map). It shows #1 reaching nearly to 50 north, but it really gets only to 30 north.

https://planetary.s3.amazonaws.com/web/assets/pictures/20121209_Mars_Mariner_4.jpg

#maps #Mars #Mariner 4

Jan 7, 2025 at 8:12amWeb
Show threadPhil StookeJan 8, 2025
Here is another section of the Mariner 4 image sequence with pictures located on a modern map. The previous 6 images were taken with high sun and in an area of fairly bland landscapes (at this resolution), but here we get recognizable craters. Some are named after explorers (before they became unfashionable). Mariner itself gets a crater named after it.
#maps #Mars #Mariner4
Show threadPhil StookeJan 8, 2025
The last of these Mariner 4 maps with image locations, curving towards the terminator and becoming very low contrast and hard to interpret. A few remaining images are not shown - they can't be located like this, only roughly based on pointing data. See the crater named after Peter Millman - my PhD external examiner 36 years ago. And see the Mars 3 landing site... it was targeted using these images. The USSR's Mars 2 and 3 were sent to Mars before Mariner 9 mapped the planet... #maps #Mars
Show threadPhil StookeJan 8, 2025
Mars 2 and 3 had to target the southern mid-latitudes, but the only knowledge of the surface at 45 south was from Mariner 7 images of the Hellas area and these Mariner 4 images. So Mars 2 went to Hellas, which looked very smooth in Mariner 7 images (because Hellas was cloudy, not smooth). It crashed. Mars 3 went to a smooth area just southeast of Newton crater, the safest-looking area in this latitude. It landed nearby and began to operate but ceased after about 20 seconds. #maps #Mars
Show threadPhil StookeJan 9, 2025

Those were my maps for Mariner 4. What did maps look like at the time? The US Air Force made maps of the image pairs, and 4 of them are here:

https://nssdc.gsfc.nasa.gov/imgcat/html/mission_page/MR_Mariner_4_page3.html

A person usually associated with Pluto - Clyde Tombaugh - also mapped Mars and made a special map of the Mariner 4 target area. It's here:

https://nmsu.contentdm.oclc.org/digital/collection/Ms0407/id/19162

South is at the top. He maps canals using an idea of the time: they are cracks made by impacts, so he maps craters at intersections (oases). #maps #Mars

Mariner 4 Mission Page

Show threadPhil StookeJan 9, 2025
Here is my version of Tombaugh's map. North is up here. Needless to say the canals are not in Mariner 4 images and the craters are not where he surmised they might be. But one crater in that area was named after Tombaugh and I show its location. Mariner 4 showed a cratered Mars, a bit of a let-down for people who hoped for something less moon-like. They had to wait a bit longer to see 'the gates of the wonder-world open' in Carl Sagan's words. #maps #Mars
Show threadPhil StookeJan 10, 2025
Mariner 4 took its pictures in 1965. Four years later, only about a week after Apollo 11, a new flyby produced a much better imaging dataset. This was Mariner 6. It viewed the entire planet during a full rotation as it approached, and took a strip of images along 30% of the equator. The best images showed lots of craters again, but earlier views, oblique and with the Sun overhead, were hard to interpret. Too bad, because they showed parts of the giant canyon system and big valleys. #Mars
Show threadPhil StookeJan 10, 2025
Here's my map of the results - just for Mariner 6, but as a bonus the Mariner 4 images are also shown. We'll see Mariner 7 tomorrow. The map, in 2 hemispheres, shows the far encounter images of the whole planet except the far north (which was in winter darkness), and the close encounter images are superimposed. The distant images still don't show craters etc. This was how Mars mapping stood until... a week later. #maps #Mars
Show threadPhil StookeJan 11, 2025
Mariner 7 flew past Mars a few days after Mariner 6 and repeated its observations. Its far encounter images were taken closer to Mars and showed finer details, including craters near Syrtis Major. The close encounter images started at Meridiani, already seen quite well by Mariner 6. Why look at that area again? To look for changes, though I don't think any were seen. They progressed south into Noachis and then across Hellas, showing it to be featureless (because it was cloudy/dusty). #Mars
Show threadPhil StookeJan 11, 2025
Here is my composite map combining Mariners 4, 6 and 7. This was the state of knowledge of the planet until Mariner 9 changed everything. These early missions showed mainly cratered areas, with potentially more interesting areas only seen with high sun and more distant oblique viewing. The occultation points were important - the radio signal passed through the atmosphere giving a temperature-pressure profile. Mariner 4 did this too. #maps #Mars
Show threadPhil StookeJan 12, 2025
A few extras for Mariners 6 and 7. First a closer view of the Mariner 6 images. The small white boxes are locations of high resolution frames. #maps #Mars
Show threadPhil StookeJan 12, 2025
And the same for Mariner 7, in two panels. The top one shows images in the Meridiani and Hellas regions, the lower map shows the south polar cap. The Mars 2 impact site is shown - its target was chosen using these images in apparently smooth Hellas. #maps #Mars
Show threadPhil StookeJan 13, 2025
The Mariner 6 and 7 cameras were not the only instruments to provide interesting information on the surface of Mars. A UV instrument made atmospheric measurements, among them an estimate of surface pressure which can be used to estimate topography (high elevation means low pressure). This map shows estimates of topography along tracks made during the close encounter. Knowledge of topography was still rudimentary. #maps #Mars.
Show threadPhil StookeJan 13, 2025

What maps were made from Mariner 6 and 7 data? The US Army made a map showing the far encounter markings, near encounter topographic features, and the Mariner 4 craters. It was not widely distributed but you can see a poor reproduction of it here:

https://ntrs.nasa.gov/api/citations/19730005151/downloads/19730005151.pdf

(near the end of that PDF). To see the actual M6/7 images go here:

https://ser.sese.asu.edu/M67/mar67.oldformat.html

#maps #Mars

Show threadPhil StookeJan 13, 2025
That US Army map showed the far encounter features, just albedo markings without much hint of topography except in the very best images near Syrtis Major. But two features stand out as very distinct circular markings: Nix Olympica (what we now call Olympus Mons) and a complex area forming part of Kasei Valles, north of Chryse. The Army map hinted that these were craters. This detail shows them. Their true nature was only revealed by the next Mars mission, Mariner 9. #maps #Mars
Show threadPhil StookeJan 14, 2025

Mariners 6 and 7 would have been followed by Mariner 8 but it fell into the ocean, so the honor goes to Mariner 9. It imaged almost the whole planet at about 1 km/pixel, and it was this mission which discovered the giant volcanoes, the vast rift system called Valles Marineris (named after the Mariner spacecraft), dry channels etc. It gave us a new Mars, and a new Mars map. Here is a globe of Mars made from its images (printed and stuck on a sphere):

https://airandspace.si.edu/collection-objects/photomosaic-globe-mars/nasm_A20130178000

#maps #Mars

Photomosaic Globe of Mars

This photomosaic globe of Mars was produced at NASA's Jet Propulsion Laboratory using photographs from the Mariner 9 spacecraft that imaged the red planet from orbit from 14 November 1971 to 27 October 1972.

Show threadPhil StookeJan 14, 2025
It looks a bit bland. The pictures are high pass filtered, a process which emphasizes small details and subdues larger variations. The effect is to make craters etc. show up but to suppress the familiar dark markings. If I were doing this now I would make the high pass filter mosaic and an albedo map and merge the two, but that's easy for me to say. The Army and Air Force gave up Mars mapping at this time (and Moon mapping about 1976), and the US Geological Survey took on the job. #maps #Mars
Show threadPhil StookeJan 14, 2025

I need a Mariner 9 map of Mars for my sequence, but there is no obvious map to work from. The Mariner 9 images, though technically available, are not easy to navigate and work with like modern datasets. So I had to use the USGS map. The original was a Mercator Projection from about 60 N to 60S and two polar azimuthal maps. I scanned them, projected them to simple cylindrical and combined them to make this:

https://www.planetary.org/space-images/global-map-of-mars-from-mariner-9

#maps #Mars

Global map of Mars from Mariner 9 data (1971)

Mariner 9 was the first Mars orbiter. The more than 7,000 images it acquired provided the first detailed views of all of Mars, revealing that the planet…

The Planetary Society
Show threadPhil StookeJan 14, 2025
Also I had stripped off the grid, names etc. so it was just the base map (a ghost of the grid is faintly visible). Then it was projected into my standard map form, which is attached. Names were added again - the original names would have been illegible at this scale. USGS also made a set of 30 map sheets covering the planet at a standard scale (1:5,000,000), thenm a set of geological maps. This scheme is still used now but it's all digital. #maps #Mars
Show threadPhil StookeJan 15, 2025

After Mariner 9 was Vik - no, wait, we should look at Mars 4 and Mars 5, two Soviet Mars missions which provided some images. They were supposed to go into orbit but only Mars 5 did. Mars 4 took images during a flyby. The Soviets did publish some maps of the small area they observed:

https://planetarymapping.elte.hu/mars-maps-from-mars-5-images-1980/

Here is my map of the Mars 4 image coverage. The base is the Mariner 9 map seen previously. #maps #Mars

Mars maps from Mars-5 images (1980) – Digital Museum of Planetary Mapping

Show threadPhil StookeJan 16, 2025
Oops, I made a mistake in my last post which I have now corrected. I said it showed combined Mars 4 and 5 image coverage, but it was only Mars 4. Here is the Mars 5 coverage. There were framing camera images and scanning camera swaths - the scanner was like those tested by Lunas 19 and 22, but greatly improved. The framing camera images were shot on film, developed, scanned and transmitted (like Luna 3 and Lunar Orbiter). #maps #Mars
Show thread🇳🇿   💉*10 RogerJan 15, 2025
@PhilStooke fascinating stuff!
Show threadPhil StookeJan 16, 2025
@rogerparkinson Thanks!
Show threadV MartínJan 13, 2025

@PhilStooke mind-blown! I went and searched for more info, this page gave some hints
https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1971-051A-02

but it wasn't enough, found this paper too to read later
https://lasp.colorado.edu/pdr/mariner9/publications/Hord_icar_1972.pdf

Maybe there are better ones?

I'm guessing the Martian weather was negligible to affect the topographic profiles?

Show threadV MartínJan 13, 2025

@PhilStooke (I know, these are Mariner 9, but I wasn't aware one could do topographic profiles with UV measurings 😉 )

This text from the above paper makes it click for me. Also attach a couple good figures there.

From Hord et al. "Mariner 9 Ultraviolet Spectrometer Experiment: Photometry and Topography of Mars"
https://lasp.colorado.edu/pdr/mariner9/publications/Hord_icar_1972.pdf