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Pluto System Cartography, places and names
Gennady Ionov
post Aug 10 2015, 07:35 PM
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With the use of metadata of LORRI frames I clarify trajectory of New Horizons (error is about 0.000002 on distancies to Pluto at snapshots momens). After that it made possible to simulate all frames with subpixel accuracy. As a bonus Pluto radius was determined: R=240.89 km * u, where 'u' is LORRI pixel size in microradians.
If we assume that the under-Charon avarage point has longitude 0, then the map of Pluto (for example http://www.unmannedspaceflight.com/index.p...t&id=37374) is offset by 1.6 to the east. So I had to make such correction to map, that the image consistent with LORRI frames.
Nevertheless, clear to see that there are still quite a strong distortion in the map.
Another file, which I posted earlier in http://www.unmannedspaceflight.com/index.p...8071&st=30:
Attached Image

There is a general shift of the East, which I removed, but there are still some parts of the motion relative to each other.
To generate frames I used this map:
Attached Image

Map was taken from
http://www.unmannedspaceflight.com/index.p...st&id=37232
and enlarged to the right (eastern) side and manually filled in the southern region based on the map obtained by the Hubble Space Telescope observations.
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Gennady Ionov
post Aug 10 2015, 08:46 PM
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Rebuilt pictures with the map
http://pluto.jhuapl.edu/Multimedia/Science..._PS723_HR-g.jpg
and obtained with offset = 0
Attached Image

Maybe tomorrow I will do a map based on a backward projecting of the LORRI images ...
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scalbers
post Aug 10 2015, 09:16 PM
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Interesting in that I had also noticed a North-South in my map compared with the official one near Tombaugh Regio. If we have the lat/lon subpoints readily available for the images (and if they are accurate) we can perhaps check and refine the maps better.


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Gennady Ionov
post Aug 11 2015, 07:58 AM
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QUOTE (Bjorn Jonsson @ Aug 11 2015, 12:25 AM) *
Regarding NH's trajectory, if I remember correctly the flyby didn't occur at exactly the planned time (off by some seconds but well within the required accuracy) and this makes it more tricky to use the metadata to accurately determine the viewing geometry (especially in the hi-res images) until an updated trajectory (SPICE kernels) becomes avvailable.

At first I tried to use the data from
http://ssd.jpl.nasa.gov/horizons.cgi#top
2457218.000000000 = A.D. 2015-Jul-14 12:00:00.0000 (CT)
NH:
r[km] 1.197739374505814E+09 -4.443897760753548E+09 -1.747680731829689E+09
v[km/s] 5.534336802447741E+00 -1.252001712778965E+01 -4.846832563458260E+00
Pluto:
1.197726655664916E+09 -4.443893298780707E+09 -1.747673432906277E+09
5.379986303470789E+00 8.159673817708096E-01 -1.389030301906091E+00
Charon:
1.197712275411875E+09 -4.443906278626040E+09 -1.747670469452485E+09
5.388459229072444E+00 8.566266433864180E-01 -1.169827709122328E+00

but I found that the position of NH was displaced approximately 120 seconds, so I used the least squares method (with using distances to Pluto, Charon, Nix and Hydra up to 2,000,000 km) to made a correction of 3D position (about 1,665 kilometers) and velocity vector (about 11.6 m/s) so that the simulated distances become coincide to metadata with an error of about 0.1 km.
r0_NH {1.1977391023383e9, -4.44389934311302e9, -1.74768117382772e9}
v0_NH {5.53196172582933, -12.51701129448342, -4.85774060000822}

For the calculation of rotation of Pluto and Charon, I used data from
http://link.springer.com/article/10.1007%2Fs10569-010-9320-4
North pole: alpha0=132.993, delta0=-6.163, turn: W=237.305+56.3625225d
Attached Image

but turn does not coincide with data from http://ssd.jpl.nasa.gov/horizons.cgi#top
so I use turn W=304.155524+56.3625225d and changed GM=873.22336378 km^3/s^2 for Pluto (instead 872.4 km^3/s^2).
As a result I got the following location of Charon relative Pluto:
Attached Image

So if we take the Charon position as the origin point on Pluto, the ambiguity is not more than 0.1 degrees in latitude and 0.01 degrees in longitude. While for the purposes of mapping accuracy it is sufficient.
QUOTE (scalbers @ Aug 11 2015, 02:16 AM) *
Interesting in that I had also noticed a North-South in my map compared with the official one near Tombaugh Regio. If we have the lat/lon subpoints readily available for the images (and if they are accurate) we can perhaps check and refine the maps better.

The main ambiguity is in position of Pluto center in frames. The given in metadata values are too bad, so I adjust it manually.
Only selfconsistent automatic map generation procedure can give accurate parameters...

Now I generate grids for all available LORRI frames. To better quality size is doubled to 2048x2048. Steps are 1,5,10 and 30 degrees.
For example:
Attached Image

You can get grids in folder "Grids" from
ftp://gionov:NG@46.45.15.20/_Data/_LORRI/
The source images placed in "Source", simulated images in "Simulate".
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Habukaz
post Aug 26 2015, 10:02 AM
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Bah, apparently there will be disagreement over the naming.


An IAU press release from March already says something similar:

QUOTE
Please note, however, that votes for other themes will not be taken into account, incl. the following, since these themes have already been used on Mercury, Venus and Mars:

  • Space missions and spacecraft names.
  • Authors, artists, directors and producers of the fiction of exploration.
  • Explorers of the Earth, air and seas.


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Bill Harris
post Aug 26 2015, 01:25 PM
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IAU should have had at least a provisional, if not formal, series of names already in place before the Pluto encounter. The time of the flyby has been known for ten years and many albedo features on Pluto have been known for longer. The surface of Charon was a general unknown, but give what we know of similar bodies there were to be Regios Chasmas and Craters to be named.

Although IAU did have the "exclusion disclaimer" in their Spring 2015 (!!) naming campaign announcement, this was a "shot across the bow" in response to prior discussions with the NH Team.

Informal names are good. I've got many 67P/C-G features named after the "Rocky and Bullwinkle" pantheon. Let me tell you about Fenwick Boulder on Frostbite Falls Planum... smile.gif

--Bill


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JRehling
post Aug 26 2015, 02:57 PM
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Names are always a sign of the times, and Pluto's naming represents a turn towards pop culture that would have been unthinkable when names were being applied to the front/back sides of the Moon, or Mars, Mercury, or the Galileans.

Decades and centuries hence, the names on Pluto will identify who and when the namers were just as the names on the backside of the Moon are an eternal nod to Mother Russia.
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FOV
post Aug 26 2015, 09:35 PM
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It is Sputnik Planum AFAIC. The IAU can't change THAT.
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Phil Stooke
post Aug 26 2015, 11:50 PM
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Don't worry too much about names. Anyone can name anything, anyway they like. The only question is whether other people will use those names.

For instance, near my house in London, Ontario, down by the river, there's a big boulder which we (my family) call Mermaid Rock. Nobody else uses the name. That's fine. I could make a map of Europe with my own idiosyncratic names for all the countries and major cities. Nobody else would use them. National Lampoon once published a world map full of humorous names. Anyone can name anything.

The IAU has an important role in deciding official names, but they have no say over unofficial names. The only question is whether anyone will use the names. So most planetary scientists will stick with official names, but you still see references even in refereed papers to Inca City on Mars, or the Schneckenberg on the Moon. And of course all those names of rocks etc. at the Mars landing sites.

As for Pluto, maybe there will be two maps, with official names and unofficial names. That's OK, we can cope with it. Chances are most people will use official names and a few will use the unofficial names that become most well-known. Like Mount Sharp on Mars, not official but we all know what it means.

Phil



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Herobrine
post Aug 27 2015, 12:43 AM
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I don't agree that names have the capacity to be official. I wouldn't even accept as valid a statement that a person or group considers their names for extraterrestrial features to be official unless they also claimed to have ownership of the features in question. Otherwise, they either don't understand the meaning of the word "official" and that they mean to say they like those names and feel others should adopt them, or are simply speaking a different (though very similar) language than I speak.
I've noticed, throughout my lifetime, that people like to throw the word "official" around, usually affixing it to something to superficially strengthen an argument or to try to build some precedent for future trust. I don't recall reading about the Prime Minister of Pluto or the Plutonian Senate delegating the task of naming features on Pluto to the IAU so they'd have more time for skiing at Norgay Montes.
I recognize that many people (and other entities) adopt IAU naming for extraterrestrial features, and that's perfectly fine; it can be very helpful to have a go-to source for names that you feel confident many other people with whom you communicate will have similarly adopted. That doesn't make those names official, unless you take a more relaxed meaning of that word, allowing for there to be multiple, different, official names for a thing, provided by multiple, different sources. As far as I am aware, however, the IAU has not claimed ownership of Pluto or any geographical subset of it, nor have they been designated the official namers by anyone who does make such a claim of ownership, so the names they assign are not even considered by them to be official (though they may say that; as I said earlier, they'd simply be misspeaking in that case, actually meaning that they like those names and feel others should adopt them).
As Phil said, people will call things whatever they want, and fortunately, usefully, a lot of people will gravitate toward the same names, making communication about those features simple and convenient. I think where Phil and I probably disagree is on the validity of affixing the word "official" to anyone's provided names.

Edit (added 2015-08-31): Note: I do not mean to sound critical of the IAU. As I said, it is very helpful for people to be able to refer to features on other worlds by names that others will understand, and the IAU is (I believe) the most popular source for such names and assigns them with a consistent style/convention. My above comments are merely me engaging in pedantry with regard to how people misuse the word "official". Personally, I'll be using whatever names I'm used to (currently, those the team has come up with) until a time comes when most people are using different names, at which time, on a name-by-name basis, I'll transition to using whatever those are, irrespective of who came up with them, so that I can be understood.
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mcaplinger
post Aug 27 2015, 03:55 AM
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The topic of naming might be considered as an addition to rule 1.9. [MOD- Noted.]

http://planetarynames.wr.usgs.gov/Page/Introduction and http://planetarynames.wr.usgs.gov/Page/Rules are the most succinct statements of current IAU policy. And yes, IAU uses the word "official" a lot; e.g., from http://planetarynames.wr.usgs.gov/Page/FAQ

QUOTE
The International Astronomical Union (IAU) Working Group for Planetary System Nomenclature provides a unique system of official names for planetary surface features, natural satellites, dwarf planets, and planetary rings for the benefit of the international science community, educators, and the general public. A single system of official names is critical for effective scientific communication.


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Disclaimer: This post is based on public information only. Any opinions are my own.
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nprev
post Aug 27 2015, 04:23 AM
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MOD NOTE: Recall that Aeolis Mons--as it is officially named by the IAU--at the MSL landing site is unofficially known as Mt. Sharp. Same principle applies here. Feel free to call Plutonian features anything you'd like, and it's extremely likely that some of the informal names will persist indefinitely...but the IAU names will be official.

Debates and/or complaints about the validity of IAU names will not be permitted. Many planetary science pros are in fact IAU members (see rule 2.6) and rants in general are not allowed under rule 2.4. As mcaplinger previously noted, rule 1.9 covers contentious topics that really have no bearing on science; although IAU naming processes and conventions are not specifically cited in this rule, note that a previous IAU action is. That may be indicative.


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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Explorer1
post Aug 27 2015, 06:21 AM
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Nothing wrong with multiple names as long as we stay consistent. Anyone remember Ultreya Abyss aka El Dorado at Gusev?
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Bill Harris
post Aug 27 2015, 09:02 AM
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"Ultreya" was hardly widespread and was an annoying local quirk. And it was more a rant proposing an oddball theory of the nature of the feature than simply an alternate name. wacko.gif

--Bill


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Habukaz
post Aug 27 2015, 10:09 AM
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The problem with more than one set of names is that it effects communication negatively - the reader will need more familiarity with the subject in order to know which names refer to the same thing.

(I'll make a biased exception for names like the heart, because they are highly intuitive wink.gif)


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