Urakkalan and Vland

[Kakistocrat]

Ooh, more data to update in the wiki. This is great.

Note that a star’s luminosity affects the extents of its habitable zones, so (for example) if two F8 V stars have different luminosities, their habitable zone extents could also differ.

Now to decide if I need to convert the python to a spreadsheet, or update the python to output a CSV…

From those two options, I’d pick option #3 — write a tool that converts the output of hzinput.py into a CSV file. That way, should hzinput.py be updated, you wouldn’t have to patch your customizations into the newer version; you’d only have to update your tool to accommodate any changes in the newer version’s output.

Note that the same site also has hzcalc.py, which is targeted towards batch processing.

 

[Kakistocrat]

I decided to modify hzinput.py to have it generate some extra details; my modified version is called hz.py. It now accepts command-line options, so that it can also be run batch-style:

• -t temperature for a star’s effective temperature (in kelvin);
• -l luminosity for a star’s luminosity (in Sol luminosities);
• -m mass for a star’s mass (in Sol masses);
• -o to generate optimistic habitable zone data (it now defaults to not do so).

With these modifications, it now produces the following conservative habitable zone and Terra-equivalent orbital data for the four Urakkalan models above:

Mass	Effective temperature	Luminosity	Conservative habitable zone	Terra-equivalent orbit
1.14 Sol	6154 K	1.7275 Sol	1.221098802 – 2.134567476 au 182,673,780.8 – 319,326,749.3 km orbits 3.452593331 – 4.531541558	1.314343943 au 196,623,055.2 km orbit 3.607774456 orbital period of 515.477297897 standard days
1.14 Sol	6154 K	1.8421 Sol	1.260951488 – 2.204232803 au 188,635,657.7 – 329,748,533.8 km orbits 3.520969448 – 4.588351098	1.357239846 au 203,040,191.0 km orbit 3.673917951 orbital period of 540.917339368 standard days
1.14 Sol	6154 K	2.0196 Sol	1.320305579 – 2.30798797 au 197,514,903.2 – 345,270,086.0 km orbits 3.617150473 – 4.66901767	1.421126314 au 212,597,470.6 km orbit 3.767126934 orbital period of 579.555488169 standard days
1.14 Sol	6154 K	2.1532 Sol	1.363276545 – 2.383104273 au 203,943,268.3 – 356,507,325.0 km orbits 3.682987537 – 4.724726132	1.467378615 au 219,516,716.3 km orbit 3.831037607 orbital period of 608.077983924 standard days

(The star’s mass is needed to calculate the orbital periods.)

For comparison, a 479.21 standard day orbital period around Urakkalan corresponds to orbit 3.50580429; 187,288,880.0 km; and 1.251948836 au.

 

[G. Kashkanun Anderson]

I like the tables! I do wish we could just get rid of those Traveller orbits, though, as they are really more trouble than they are worth.

You know, I think that starting with luminosity and then applying stellar temperature would be the best way to go for coming up with reasonable host stars for Traveller shirtsleeve worlds. It might even do something to throttle back the plague-like overabundance of F and G Type stars that infect the OTU (to say nothing of the sheer lunacy of an Earthlike world orbiting a supergiant star).

The radius, of course, could then be 'backfilled' from the two points of information known, along with a range of mass possibilities (as well as, I suppose, metallicities, if you wanted to go that far).

A few other color points about Vland, from back when I was musing about it around a decade or so ago:

There is a Mira variable called Chi Cygni probably within about 10-12 parsecs of Vland. According to my estimations at the time (and it was a while ago, so I make no current guarantees about this), it ranges from -2.86 magnitude brightness (roughly equal to the lower end of Jupiter's visibility in our sky) to +8.06 (definitely, completely, invisible to the naked eye) over the course of about 407 Standard Days.

Deneb is, of course, about 60 parsecs from Vland. And it is, equally of course, searingly bright -- to the tune of about 200,000 times the luminosity of the Sun. This means that it is, at a minimum, about -4.5 magnitude in Vland's sky, or about the same as Venus is at its nearest brightness in our own sky.

These might be exaggerated a bit, because I do not really know (or, really, I'm just to lazy to know) how to calibrate for Urakkalan's presumed increased brightness in Vland's sky. But they are still very significant. Deneb, for example, is almost certainly bright enough to be seen under all conditions short of cloudiness or occultation.

I would have to imagine both of these have some sort of role in ancient Vilani cultural myths and legends. In a semi-canonical map I made up of the Ziru Sirka at foundation (which used to be on this site, although now I don't know where it would be, or if it survived the transfer), I gave Deneb, which at the time laid just outside of Amshuushigerun (aka settled, or 'civilized') space, the name Sudrehiirushu, which, if I recall correctly, means something like 'the eternal champion' in reconstructed Old High Vilani. The accompanying legend, in my head canon, being that Deneb was Vland's original sun, during some twilight age before the birth of Urakkalan.

 

[Kakistocrat]

I like the tables! I do wish we could just get rid of those Traveller orbits, though, as they are really more trouble than they are worth.

I think that the main reason that the orbit numbers still need to be retained (at least for classic Traveller) is for the sake of captured planets. Book 6, page 34 shows that they receive an orbit number with one decimal place, so computing orbit numbers for a habitable zone is handy for knowing if a captured planet is in the habitable zone. (I’ve generated a Titius-Bode table with radii for orbit numbers 0.0 through 19.0 with steps of 0.1, but I haven’t made a .png version of that table yet.)

You know, I think that starting with luminosity and then applying stellar temperature would be the best way to go for coming up with reasonable host stars for Traveller shirtsleeve worlds. It might even do something to throttle back the plague-like overabundance of F and G Type stars that infect the OTU (to say nothing of the sheer lunacy of an Earthlike world orbiting a supergiant star).

The radius, of course, could then be ‘backfilled’ from the two points of information known, along with a range of mass possibilities (as well as, I suppose, metallicities, if you wanted to go that far).

There’s an article called The Real Starry Sky (from 2001) that provided data on star density per 10,000 pc³ by spectral type for stars brighter than absolute magnitude +16. It has separate classes for giants (luminosity classes I through IV combined), main sequence dwarfs (V), and white dwarfs (VII); I don’t know if subdwarfs (VI) were combined with the main sequence or ignored. Perhaps the creation of new tables to generate spectral type and luminosity class could be based on the data from Table 2 in the article, if no more recent star density data are available.

Deneb is, of course, about 60 parsecs from Vland. And it is, equally of course, searingly bright — to the tune of about 200,000 times the luminosity of the Sun. This means that it is, at a minimum, about −4.5 magnitude in Vland’s sky, or about the same as Venus is at its nearest brightness in our own sky.

Yes, I’ve done a bit of calculation regarding Deneb and Antares from Urakkalan and Sol. In the canonical Traveller sector arrangement, Deneb is 62 pc spinward and 8 pc rimward of Urakkalan, for a distance (hypotenuse) of 62.514 pc; and Antares is 71 pc trailing and 4 pc rimward of Urakkalan, for a distance of 71.113 pc. In the same canonical arrangement, from Sol, Deneb is 95 pc spinward and 162 pc coreward = 187.8 pc; but in actual space, Deneb is 430 pc spinward and 43 pc coreward (and 15 pc upward) = 432.9 pc. The position of Antares from Sol is worse: canonically it’s 38 pc trailing and 166 pc coreward = 170.294 pc, but in actual space it’s 23 pc spinward and 162 pc rimward (and 44 pc downward) = 169.78 pc. (Ironically, the Sol–Antares distance is nearly correct, but the direction is way off.)

It’s easier to imagine the Deneb–Urakkalan relationship being canonical, since (to my knowledge) an F8 V star hasn’t been identified within 63 pc of Deneb; but since Antares is actually rimward of Sol, its canonical position (and thus its canonical distance to Urakkalan) should be corrected. I don’t know how such a correction would affect the brightness of Antares in Vland’s night sky.

I would have to imagine both of these have some sort of role in ancient Vilani cultural myths and legends. In a semi-canonical map I made up of the Ziru Sirka at foundation (which used to be on this site, although now I don’t know where it would be, or if it survived the transfer), I gave Deneb, which at the time laid just outside of Amshuushigerun (aka settled, or ‘civilized’) space, the name Sudrehiirushu, which, if I recall correctly, means something like ‘the eternal champion’ in reconstructed Old High Vilani. The accompanying legend, in my head canon, being that Deneb was Vland’s original sun, during some twilight age before the birth of Urakkalan.

I’d certainly agree with their presence in ancient Vilani cultural myths and legends. Perhaps some battle was fought (or some wager was laid) between Deneb and Urakkalan over Vland, and Urakkalan emerged the victor (through some quintessentially Vilani attribute that Urakkalan exhibited).

I was browsing through the Imperial Encyclopedia regarding the Vilani calendar, and there’s more than one equivalence ratio between the Vilani year and the Imperial year provided in various articles there. I found that in Supplement 8, page 10, there’s a chronology of events with years given in Imperial, Vilani, and Terran reckonings; depending upon which events are chosen as endpoints, the Vilani years work out to between 1.3308026… and 1.3314737… standard years (or between 486.07565… and 486.212385… standard days). I didn’t check all of the event differences, so there might be smaller or larger equivalences to be found there as well.

 

[whulorigan]

The position of Antares from Sol is worse: canonically it’s 38 pc trailing and 166 pc coreward = 170.294 pc, but in actual space it’s 23 pc spinward and 162 pc rimward (and 44 pc downward) = 169.78 pc. (Ironically, the Sol–Antares distance is nearly correct, but the direction is way off.)

. . . but since Antares is actually rimward of Sol, its canonical position (and thus its canonical distance to Urakkalan) should be corrected.

Check your sources/data for Antares. According to SIMBAD, the Antares star system is approximately 170pc from Terra, and is located at a bearing from Terra of 351.9° Galactic Longitude^* and +15.1° North Galactic Latitude. This places it slightly trailing of coreward, and at a moderate northern inclination from the galactic plane. For relative reference, Antares is in Scorpius. Deneb is in Cygnus. Where are those constellations located in the night sky relative to one another? Scorpius and the western edge of Sagittarius are in the general direction of the galactic center. Rigel and Betelguese are rimward-trailing-south in Orion.

^* For readers who are unfamiliar, Galactic Longitude is measured from 000.0° (due coreward) and increases counterclockwise to 090.0° due spinward, to 180.0° due rimward, and to 270.0° due trailing. ​

 

[Kakistocrat]

Check your sources/data for Antares. According to SIMBAD, the Antares star system is approximately 170pc from Terra, and is located at a bearing from Terra of 351.9° Galactic Longitude^* and +15.1° North Galactic Latitude. This places it slightly trailing of coreward, and at a moderate northern inclination from the galactic plane.

My source for Antares data is the ICRS equatorial coördinates on SIMBAD, with α (right ascension) = 16h 29m 24.45970s, δ (declination) = -26° 25′ 55.2094″, and π (parallax) = 5.89 ± 1.00 mas. Using the iauIcrs2g() function in the SOFA astronomy library, those equatorial coördinates resulted in galactic coördinates l (galactic longitude) = 351.947131313457°, b (galactic latitude) of +15.064324703365°, and r (radius = distance from Terra) of 169.779286926995 pc.

I’d converted l, b, r (galactic spherical coördinates) to U, V, W (galactic Cartesian coördinates) using r cos b cos l, r cos b sin l, and r sin b respectively = 162.328139855781 pc, -22.966496121611 pc, and 44.126197845463 pc from Terra respectively.

If that conversion was mistaken, and r sin b cos l, r sin b sin l, and r cos b respectively should have been used instead, then U, V, W results in 43.691079452543 pc, -6.181497599168 pc, and 163.944761835022 pc from Terra respectively. However, a W of almost 164 pc doesn’t reflect a moderate “northern” inclination from the galactic plane, so I think that the original trigonometric conversion was correct.

If the original trigonometric conversion to Cartesian was correct, then I must have misinterpreted U and V regarding Antares. If U is positive corewards and negative rimwards, V is positive spinwards and negative trailing, and W is positive upwards and negative downwards (i.e. a “right-hand” rule), then that would match a position that is slightly trailing of coreward with an upward inclination from the galactic plane. If you found that my description of the actual position of Deneb was on target, then that would suggest that Antares is really 162 pc coreward, 23 pc trailing, and 44 pc upward of Sol, which puts Antares 119 pc coreward, 453 pc trailing, and 29 pc upward of Deneb, which is still quite different to their positions in the canonical Traveller sector arrangement.

 

[whulorigan]

My source for Antares data is the ICRS equatorial coördinates on SIMBAD, with α (right ascension) = 16h 29m 24.45970s, δ (declination) = -26° 25′ 55.2094″, and π (parallax) = 5.89 ± 1.00 mas. Using the iauIcrs2g() function in the SOFA astronomy library, those equatorial coördinates resulted in galactic coördinates l (galactic longitude) = 351.947131313457°, b (galactic latitude) of +15.064324703365°, and r (radius = distance from Terra) of 169.779286926995 pc.

I’d converted l, b, r (galactic spherical coördinates) to U, V, W (galactic Cartesian coördinates) using r cos b cos l, r cos b sin l, and r sin b respectively = 162.328139855781 pc, -22.966496121611 pc, and 44.126197845463 pc from Terra respectively.

If that conversion was mistaken, and r sin b cos l, r sin b sin l, and r cos b respectively should have been used instead, then U, V, W results in 43.691079452543 pc, -6.181497599168 pc, and 163.944761835022 pc from Terra respectively. However, a W of almost 164 pc doesn’t reflect a moderate “northern” inclination from the galactic plane, so I think that the original trigonometric conversion was correct.

If the original trigonometric conversion to Cartesian was correct, then I must have misinterpreted U and V regarding Antares. If U is positive corewards and negative rimwards, V is positive spinwards and negative trailing, and W is positive upwards and negative downwards (i.e. a “right-hand” rule), then that would match a position that is slightly trailing of coreward with an upward inclination from the galactic plane. If you found that my description of the actual position of Deneb was on target, then that would suggest that Antares is really 162 pc coreward, 23 pc trailing, and 44 pc upward of Sol, which puts Antares 119 pc coreward, 453 pc trailing, and 29 pc upward of Deneb, which is still quite different to their positions in the canonical Traveller sector arrangement.

I am curious as to why you are calculating. SIMBAD actually lists the Galactic Coordinates directly on its data page; you shouldn't need to do a calculation.

Nevertheless, Deneb is the one that is very wrong on the Charted Space Map. It is almost half the distance from Sol it should be, and it should be almost due Spinward.

But one thing I have noted is that many of the canonical stars on the Charted Space Map (not all) seem to be about 30°-45° rotated clockwise from their true bearings. Alpha Centsuri and Barnard are two good near Terra examples. Why this is I am not sure.

 

[Kakistocrat]

I am curious as to why you are calculating. SIMBAD actually lists the Galactic Coordinates directly on its data page; you shouldn’t need to do a calculation.

The program that I’d written uses a text file of stars with their equatorial coördinates as a data store. I’d originally used data sources other than SIMBAD, and they often didn’t have galactic coördinates, so I chose to store the equatorial coördinates in the text file and used SOFA to convert them to galactic coördinates. Even though SIMBAD also provides galactic coördinates, I still keep equatorial coördinates in that text file.

Nevertheless, Deneb is the one that is very wrong on the Charted Space Map. It is almost half the distance from Sol it should be, and it should be almost due Spinward.

Yes, that matches the “430 pc spinward and 43 pc coreward (and 15 pc upward) = 432.9 pc” mentioned above. Thanks to your eagle eye on Antares’ position, I’ve updated my program to also print “(coreward)” or “(rimward)” for the distance on the U axis, “(spinward)” or “(trailing)” for the distance on the V axis, and “(upward)” or “(downward)” for the distance on the W axis, which I hope will reduce my future misinterpretations — thank you for bringing that to my attention!

But one thing I have noted is that many of the canonical stars on the Charted Space Map (not all) seem to be about 30°–45° rotated clockwise from their true bearings. Alpha Centauri and Barnard are two good near Terra examples. Why this is I am not sure.

Yes, those two stood out to me during my experiment with a 3D “hex” map near Sol. In the Sol subsector map of Supplement 10, Barnard should be two hexes to the left, and Prometheus (α Centauri) should be roughly where Barnard is, so for those two systems, it seems to be a 60° rotation (on a hex grid).

I haven’t yet tried calculating Barnard’s position after 3603 years of proper motion and radial velocity to see where it would be in AD 5626 (1105 Imperial), but a rough estimate gives a bit over 0.5 pc movement — and given its radial velocity, the majority of that will be in a Sol-ward direction.

 

[whulorigan]

Yes, that matches the “430 pc spinward and 43 pc coreward (and 15 pc upward) = 432.9 pc” mentioned above. Thanks to your eagle eye on Antares’ position, I’ve updated my program to also print “(coreward)” or “(rimward)” for the distance on the U axis, “(spinward)” or “(trailing)” for the distance on the V axis, and “(upward)” or “(downward)” for the distance on the W axis, which I hope will reduce my future misinterpretations — thank you for bringing that to my attention!

Glad to be of help. I am the one who originally detailed the majority of the very basic " Star " articles on the TravellerWiki using the SIMBAD data as one of the sources for positional information. Deneb, Antares, and Rigel were benchmark stars for me in terms of situating the location of Charted Space in my mind.

If you do the "45° " rotation mentioned below, Deneb lies roughly along the correct bearing in the transformed coordinate axes but should be on the far edge of the Zhodani Consulate along that bearing. It is interesting to note that on the MT CD from FFE there is an early hand-drawn map of Charted Space among the files on the CD that includes specific locations of many real-world stars on the map, and includes Right Ascension values under the Coreward, Spinward, Rimward, and Trailing Axis labels, and also has a note in the lower right corner stating that all stars listed lie within ±10 ° Declination. On that map Deneb does lie on the far side of the Consulate in what is now Bliardlie Sector at twice the distance that it would later occupy on the published map (and Antares lies in what would later be Ley Sector). So GDW-folk were aware of the "correct" distance for Deneb at some point, but then later either deliberately made a change for gaming purposes or made an unintentional error that propagated thru successive published materials.

Yes, those two stood out to me during my experiment with a 3D “hex” map near Sol. In the Sol subsector map of Supplement 10, Barnard should be two hexes to the left, and Prometheus (α Centauri) should be roughly where Barnard is, so for those two systems, it seems to be a 60° rotation (on a hex grid).

And it is not only those two. Some of the other canonically located stars around the Solomani Rim are similarly so rotated by about the same amount:

• TauCeti/Iilike
• Procyon/Fenris
• Wolf 359/Junction
• Sirius/Sirius
• Shulimik/Epsilon Eridani
• Nusku/61 Cygni
• Sarpedon/40 Eridani
• MIrabilis/82 Eridani
• Deneb/Deneb (See Above)

I haven’t yet tried calculating Barnard’s position after 3603 years of proper motion and radial velocity to see where it would be in AD 5626 (1105 Imperial), but a rough estimate gives a bit over 0.5 pc movement — and given its radial velocity, the majority of that will be in a Sol-ward direction.

Yes. It really might be in one of the two adjacent hexes to Terra in the 57th Century. (And it is also interesting to note that Polaris will not have been Terra's pole-star for a long time by the 57th century, either).

 

[Kakistocrat]

It is interesting to note that on the MT CD from FFE there is an early hand-drawn map of Charted Space among the files on the CD that includes specific locations of many real-world stars on the map, and includes Right Ascension values under the Coreward, Spinward, Rimward, and Trailing Axis labels, and also has a note in the lower right corner stating that all stars listed lie within ±10° Declination. On that map Deneb does lie on the far side of the Consulate in what is now Bliardlie Sector at twice the distance that it would later occupy on the published map (and Antares lies in what would later be Ley Sector).

I haven’t seen that map. Deneb has a +45°-and-change declination, though. Or did you mean that all of the stars on that map are within 10° declination of each other?

And it is not only those two. Some of the other canonically located stars around the Solomani Rim are similarly so rotated by about the same amount:

• TauCeti/Iilike
• Procyon/Fenris
• Wolf 359/Junction
• Sirius/Sirius
• Shulimik/Epsilon Eridani
• Nusku/61 Cygni
• Sarpedon/40 Eridani
• MIrabilis/82 Eridani
• Deneb/Deneb (See Above)

On a 3D map, Iilike (τ Ceti) should be one hex (well, 1.033 hexes) rimward and four hexes (i.e. 3.499 hexes) downward of Sol; it’s only an eighth of a parsec coreward. In Supplement 10, Iilike is in the neighboring Dingir subsector. I wonder if the general rotation that you’ve observed is some kind of mathematical amalgamation with a flattened W axis for the sake of a 2D hex grid?

[Barnard] really might be in one of the two adjacent hexes to Terra in the 57th Century. (And it is also interesting to note that Polaris will not have been Terra’s pole-star for a long time by the 57th century, either).

Yes, Errai (γ Cephei) will become the pole star around AD 4200, and after another millennium the pole will be about the same distance from both Alfirk (β Cephei) and ι Cephei.

 

[whulorigan]

I haven’t seen that map. Deneb has a +45°-and-change declination, though. Or did you mean that all of the stars on that map are within 10° declination of each other?

The text on the map reads:

"Map of the Imperium showing named stars (Old Earth nomenclature) between +10° and -10° declination."​

On a 3D map, Iilike (τ Ceti) should be one hex (well, 1.033 hexes) rimward and four hexes (i.e. 3.499 hexes) downward of Sol; it’s only an eighth of a parsec coreward. In Supplement 10, Iilike is in the neighboring Dingir subsector. I wonder if the general rotation that you’ve observed is some kind of mathematical amalgamation with a flattened W axis for the sake of a 2D hex grid?

I had thought of that as a possibility. Meshan is supposedly Epsilon Indi, which has an extreme southern Galactic Latitude angle despite being a close star to Terra, and it appears mirror-flipped about Terra on the Charted Space Map (Corespinward instead of Coretrailing). I have often wondered if they put it there to try and preserve a roughly mutual correct distance to all stars near to both Terra and Epsilon Indi within the limitations of the 2D map.

Yes, Errai (γ Cephei) will become the pole star around AD 4200, and after another millennium the pole will be about the same distance from both Alfirk (β Cephei) and ι Cephei.

Terra might have a southern Pole Star in the 57th Century (I haven't actually checked).

 

[Kakistocrat]

Meshan is supposedly Epsilon Indi, which has an extreme southern Galactic Latitude angle despite being a close star to Terra, and it appears mirror-flipped about Terra on the Charted Space Map (Corespinward instead of Coretrailing). I have often wondered if they put it there to try and preserve a roughly mutual correct distance to all stars near to both Terra and Epsilon Indi within the limitations of the 2D map.

Not all of the identified stars have a reasonably close canonical distance. The furthest off are Boskone (α Indi), canonically around 16 pc, but actually around 30 pc; and Gashidda (ε Ceti), canonically around 7 pc, but actually around 23.5 pc. There are a couple of stars that have a longer canonical distance than actual distance, but they’re not as far off. I’ll have to try calculating the identified stars’ U–V hypotenuses to see if any patterns emerge with either canonical distances or (2D) directions.

Terra might have a southern Pole Star in the 57th Century (I haven’t actually checked).

It looks like γ Chamaeleontis will be within 2° of the southern celestial pole around AD 4200, and ω Carinae will be next, within 1° around AD 5800.

 

[Kakistocrat]

I’ll have to try calculating the identified stars’ U–V hypotenuses to see if any patterns emerge with either canonical distances or (2D) directions.

Here’s what I came up with, comparing distances and galactic longitudes of identifed stars between the Supplement 10 hex grid and actual space (the hex grid distance is Euclidean rather than a hex count), ordered by ascending true galactic longitude:

Hex	World/Subsector	Star system	Hex grid distance (pc)	Hex grid longitude	True distance (pc)	True longitude
1824	Agidda/Sol	Ross 154	3	0°	2.975103	11.307184°
1024	Fomalhaut/Dingir	Fomalhaut	7.549834	69.443955°	7.703567	20.488135°
1926	Barnard/Sol	Barnard’s Star	1.732051	315°	1.826649	31.008699°
1911	Depot/Vega	Rasalhague	16.522712	356.423666°	14.896470	35.893747°
1522	Altair/Dingir	Altair	6.082763	30.963757°	5.129520	47.744119°
1720	Vega/Vega	Vega	7.549834	8.130102°	7.678722	67.448203°
0606	Ishadar/Ultima	ε Cygni	23.430749	29.744881°	22.291574	75.951355°
1822	Nusku/Sol	61 Cygni	5	0°	3.497165	82.319733°
0618	Stralsund/Alderamin	Alderamin	13.747727	53.130102°	15.037594	100.998971°
1429	Iilike/Dingir	τ Ceti	4	116.565051°	3.650168	173.100674°
0938	Cicero/Capella	Aldebaran	13.076697	140.710593°	20.433183	180.971906°
2029	Midway/Sol	Lalande 21185	2.645751	225°	2.546862	185.118410°
1127	Gashidda/Dingir	ε Ceti	6.082763	90°	23.536944	187.196257°
2339	Castor/Gemini	Castor	12.288206	202.619865°	15.595758	187.440991°
2236	Pollux/Gemini	Pollux	9.643651	203.962489°	10.358401	192.229281°
1530	Shulimik/Dingir	Rán	3.605551	135°	3.216055	195.844635°
1830	Fenris/Sol	Procyon	3	180°	3.514197	213.702235°
1629	Sirius/Dingir	Sirius	2.645751	135°	2.637061	227.230285°
1929	Junction/Sol	Wolf 359	1.732051	206.565051°	2.420546	244.054188°
1332	Mirabilis/Capella	82 G. Eridani	6.244998	135°	6.041413	250.746170°
2228	Loki/Sol	Ross 128	3.605551	255.963757°	3.374875	270.147075°
2227	Ember/Sol	Wolf 424	3.464102	270°	4.387889	288.759683°
2027	Prometheus/Sol	α Centauri	1.732051	270°	1.324837	315.734165°
1526	Meshan/Dingir	ε Indi	3	71.565051°	3.638947	336.192619°
2407	Cambria/Concord	ε Scorpii	20.663978	343.300756°	19.535065	348.811076°
1214	Boskone/Esperance	α Indi	14	24.77514°	30.147724	352.566842°

As can be seen above, there is a wide variety in the differences of canonical galactic longitude vs. true galactic longitude; Ross 154 is right where it should be (an 11.3° difference on a hex grid is effectively a 0° difference), but 82 G. Eridani is off by 115° at a six hex distance. A few of the stars (Fomalhaut, Lalande 21185, ε Indi, α Indi) appear to be rotated counterclockwise in canon. The stars with the least accurate distances, ε Ceti and α Indi, both happen to have a large Z axis component; however, although Fomalhaut and Aldebaran have similar Z axis components, the distance of Fomalhaut is much more accurate than that of Aldebaran.

 

[tjoneslo]

So after <checks dates> several months I've updated the Main Sequence data for the stars. This shrinks the temperature ranges, corrects the mass of the star, and re-calculates the Luminosity, uses the hzcalc.py for the habitable zone ranges. Thanks for posting the links and the discussion.

I will note there are a few odd jumps in the data. I've confirmed this is due to anomalies in the original data. Not sure why the original is wrong, nor how to recommend fixes.