The problem
I've been observing Mars a fair amount lately (best views until 2035!). I sketch what I see and then I go home and want to compare my sketch with a good Mars map. But I had great trouble finding one. For those who want to have a map to compare while they're observing, and for those imagers who want to compare their images and see what they've imaged, it's much the same problem. I've found it tough to correlate my sketches with maps, but one reason is that it's hard to correlate the maps with each other. I'm interested in maps that show visible dark and light regions (
What is needed
A solution to my problem would satisfy various needs.
1) I'd like the map to have labels for the sorts of features I might be able to see.
Many maps have no labels or too few labels, and Stellarium has the opposite problem so when you click on a large dark patch to find out what it is, it will tell you the name of a minuscule crater within that dark patch.
2) I'd like the map to match my view as far as the limbs go.
Many maps present a Mercator or Eckert projection that wraps around the whole surface of Mars in one map. Some present two maps that are the two opposite sides of Mars. But it's surprisingly difficult to figure out what anything near the limb should look like given these projections. For example, when looking at the S&T Mars Profiler, I saw the tip of Syrtis Major sticking down (Newtonian view) a little bit away from the edge, so I thought this was the bump I had sticking down on my sketch. But when I later saw images taken at the same time I realized the tip of Syrtis Major wasn't at all visible because it was too close to the limb, and my bump was in fact Comer Sinus.
3) I'd like the map to match my view as far as the polar regions go.
Because planets are tilted towards us at the poles, and because the amount of tilt varies, it can be tough to figure out what things should look like just given a map.
4) I'd like it to be a fairly accurate map.
One problem is that very old maps aren't that accurate. But there's a bigger problem, which is that the features of Mars change over time. We're all familiar with the polar caps melting throughout the season. And then there's the clouds that form on the limb that will vary from one night to the next. And clouds that form because of mountains also vary. There are the dust storms that will alter what we see, of course, but these can have longer lasting effects as well (from what I've heard on the forums, the planet-wide dust storm at last opposition has made some changes that we still see today).
Some semi-good solutions
In the past I've used the S&T Mars Profiler and Stellarium to address 2 & 3. Another nice resource is the National Geographic Mars Map from the 1970's. It shows
Some better solutions
One resource that is ideal in some respect are simply images people have taken at that time you were observing. I've often been able to do a search and find an image someone took that I can use. One big advantage of this is you'll get exactly those features that are present at that time, whether it's a polar hood, clouds over Olympus, etc. And you'll see Mars with the right tilt and rotation (assuming you find an image taken at roughly the time you were observing). One good place to search is on Cloudy Nights under Solar System Imaging and Processing. Of course, you still have to find a labelled map to know what those features are.
Another resource I recently found is Ralph Aeschliman's maps that have a labeled Mercator projection together with 9 unlabeled globular views (i.e., every 40 degrees): http://www.ralphaeschliman.com/ralphaeschliman_040.htm
Another solution is National Geographic's 2016 Mars map. This has more current
Finally, I have discovered JUPOS. If only someone had told me about it before! The program will show you a globular view of Mars (or any other planet) that is what should be visible at the time and date you specify. So it's much like Stellarium in this respect. But you can enter the image maps that it will use to show you, and these can be found on-line. So, e.g., you can enter an image map is fairly recent and that has had labels added. (Actually, the program is much more sophisticated than I've described, created for people contributing to the science of, especially, Jupiter. To get a sense of the sophistication, Mars is simple since it rotates at a particular rate, but it is designed for Jupiter which has different rotational rates at different latitudes.) You'll still have to use other maps for smaller details, but it helps so much having the globular view that should match what you see fairly closely.
To download JUPOS, go here: http://jupos.privat.t-online.de/index.htm
To get labeled images to use, go here: https://www.cloudynights.com/topic/7283 ... s-texture/
or go here (part way down): https://www.cloudynights.com/topic/6164 ... try8564610
Here's a short and simple tutorial useful for getting JUPOS going:
and here's a short tutorial to help you load images ('texture files'):
Please let me know if anything I've said is wrong or if you know of other useful resources!