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23xx's galactic neighbourhood

I'm working on a cooridor map. The HYG database is nice once you weed out unnecessary stars.

One thing I'd like to discuss before finalizing it, is what other waypoints the Bayern passed on the way. It clearly did not go straight (the French arm is the wrong direction).

Using Pentapod space rather than jumping straight from Sol is an interesting choice. Part of the reason was likely just a wish to explore/snoop a bit, part was to check on some of the stars of the Ursa Major Moving group. From Pentapod space it is also possible to get to the Capella cluster using a relatively short long jump, and Capella is an important star worth a visit on its own.

Another possible "must see" is Aldebaran.

The Hyades cluster is roughly in the same direction as the Pleiades, and for an astrophysical expedition to pass it up would be insane. It also has the benefit of a higher density of stars, making travel easier.

So we can expect the path to be roughly:

  1. Start from Sol, go out the French Arm
  2. Pentapod space: Ross 627 to the pentapod worlds and Iota Ursae Majoris
  3. Capella cluster
  4. Aldebaran
  5. Hyades
  6. The Pleiades
The way back could be the same, a shorter straight route if it was important to get back quickly, or do some side excursions if there was time.

Does this make sense? I can make maps along a cylinder of any radius along this path.
 
Anders said:
The way back could be the same, a shorter straight route if it was important to get back quickly, or do some side excursions if there was time.
Click to expand...

So basically, the crew of the Bayern are seeking out new life and new civilizations?

I'd be curious to see a map that shows the rough extent of human-explored space. It probably looks like a long stick with a ball on the end.
 
Anders said:
I'm working on a cooridor map. The HYG database is nice once you weed out unnecessary stars.

One thing I'd like to discuss before finalizing it, is what other waypoints the Bayern passed on the way. It clearly did not go straight (the French arm is the wrong direction).

Using Pentapod space rather than jumping straight from Sol is an interesting choice. Part of the reason was likely just a wish to explore/snoop a bit, part was to check on some of the stars of the Ursa Major Moving group. From Pentapod space it is also possible to get to the Capella cluster using a relatively short long jump, and Capella is an important star worth a visit on its own.

Another possible "must see" is Aldebaran.

The Hyades cluster is roughly in the same direction as the Pleiades, and for an astrophysical expedition to pass it up would be insane. It also has the benefit of a higher density of stars, making travel easier.

So we can expect the path to be roughly:

  1. Start from Sol, go out the French Arm
  2. Pentapod space: Ross 627 to the pentapod worlds and Iota Ursae Majoris
  3. Capella cluster
  4. Aldebaran
  5. Hyades
  6. The Pleiades
The way back could be the same, a shorter straight route if it was important to get back quickly, or do some side excursions if there was time.

Does this make sense? I can make maps along a cylinder of any radius along this path.
Click to expand...

Given the nature of their mission, any excursion to the Hyades would be limited at best. By the time of the Bayern's launch, their primary purpose had become figuring out what was happening in the Pleiades. Once they encountered the anomaly, the way back would have been as quick as possible. There would have been little exploration done on the way back, save for short in-system excursions as they discharged the drive. Otherwise, that sounds good.
 
The Hyades are almost straight on between the sun and the Pleiades, so the expedition would pass through them anyway. It is the Pentapod space excursion that is the major deviation in need for explanation. From a planning perspective it might make sense to use as a mild test: no need to use advanced drives, a chance to test the exploration abilities and close enough to home that if anything goes wrong the ship could return.

Going back quickly seems to be a balance between speed and safety. Retracing the original path would be safer since the terrain would be well known (with the exception for that angry alien at Argyle 692). The fastest way back would go straight. The path that would make many researchers happiest would be a different path compared to the outbound path.

What about this? Going out along the path I described, with deliberate visits to Arcturus and Capella (on the path anyway, if the expedition has to return before the Pleiades it has not been a complete loss), then the Hyades and Pleiades. After AGRA, back home as quickly as possible! This means retracing the path to the Hyades, and then going essentially straight for the Core (fast, researchers happy, slight risk).

Some points we might want to consider is: where is the Bayern Gap, the 15.1 ly gap with a brown dwarf that now enables other ships to go to the Little Guys? It seems to be close to human space (20 ly past Ross 627), it cannot be beyond DM+41 2147. Hmm, that makes it unlikely that Bayern visited Iota Ursae Majoris as I had thought. I need to look more closely to the Ross 627 neighbourhood to see where we can go (the obvious way is into the Denebola cluster, but it is even more in the wrong direction).

We should also try to fix the Little Guy world. It cannot be enormously far away from human space, or supply expeditions would be too hard. I have a hard time believing it to be 215 ly away.

Then there is ISO 912, 71.2 ly towards the Pleiades. Fortunately, we can drop that brown dwarf wherever we want :-)

Dearborn 67 is likely fairly close to the Pleiades.

Overall, we can add stars with fairly good conscience to the route since the number of real stars in my data drops off quite fast beyond 70 lightyears. We know there are lots of stars there, but we do not have their coordinates.

Overall, my impression of human explored space is a ball of yarn. A dense core, with some dangling threads and then a long tail to the Pleiades.
 
Here is a plot of the HYG stars in the rough right direction:
1_bayerntop.png

http://www.TravellerRPG.com/CotI/Gallery/index.php?n=259
The high density of the Hyades makes them stand out quite nicely. Uncertainities in parallax makes the Pleiades elongated.

1_narrow.png

http://www.TravellerRPG.com/CotI/Gallery/index.php?n=260
The green line is my suggested Bayern route. I have plotted stars within 20 ly of it, with stutterwarp links in red. You can see that we will need to fill in a lot of stars, especially beyond the Hyades.

A discrepancy I noted: the little guys are somewhere behind the Hyades if the distance 215 ly is to believed. The coordinates in 2320AD on the other hand puts them fairly close to human space, somewhere above 13 Orionis on my map (i.e. to the lower left of the Hyades). Maybe 215 ly is the distance one has to go before encountering them if following <7.7 paths.

I better sit down with Celestia and see if I can figure out the near part of the corridor.
 
Aargh! Damn pentapods! :-)

Finding a plausible start of the Bayern corridor proved far harder than I thought. The basic problem is to reconcile that it starts at Ross 627, that the Pentapods do not allow traffic beyond DM +41 2147 and that the Bayern would not take excessive detours thanks to its magic drives.

After looking at the geography in 3D it seems clear that Aldebaran and Capella make nice detours but can be skipped; the path from somewhere near Ross 627 will however almost certainly pass close to Castor. This is nice, since it lies at the heart of a big and far-ranging cluster of stars it makes a lot of sense to use.

Which easily reachable stars are closest to the Castor cluster? The closest are DM+42 1956 (12.7 ly) and G 197-50 (13.8) - a plausible distance for the Bayern gap even if it is smaller than stated. But they both lie in the Iota Ursae Majoris cluster on the other side of the Pentapod homeworld. If the Bayern corridor is open without pentapod oversight they cannot be it.

The stars close to Ross 627 are all about 30~ ly away from the closest stars of the Castor cluster. Maybe the real path is through the Denebola frontier which connects nearby, but that seems to be an awfully big detour in the opposite direction, especially for a ship that can jump long distances.

The closest star that comes before the pentapod roadblock is DM+39 2376, 24.4 ly away from the cluster. There is a star in between, DM+36 1979, 11.9 ly away. Unfortunately that one is still 19.16 ly from G 107-70, the closest cluster star. Now, if there is a brown dwarf exactly between the last two stars at (-14.75,19.75,23.95) the whole chain should be traversable with three tug links - if we also add another new dim star close to DM+36 1979 (or DM+39 2376) so there is a <11.55 jump.

So the choices are:

  • Maybe the pentapods are letting through Bayern traffic (contradicts page 161, if I was a sea of pentapod gods I would not be keen on noisy and dangerous through-traffic anyway) and the link is through the Iota UMa cluster.
  • The cooridor winds around pentapod space through the Denebola frontier, for a really long detour - but why not simply jump towards the cluster from the Berthier finger in that case?
  • Add two stars and a major investment in Trilon hardware and get the link about where it was intended.

What do you think?
 
I believe Pentapods cutting off traffic is a 2320 development (a la Colin).

There's no mention of it in 2300's base materials (was it in a Challenge?).

Bayern was launching in 2301 IIRC, which means it was before Pentapods cut off traffic.

I guess if you various conspiracy theories about the Pentapods float your boat, you could say the Pentapods closed access off because of something to do with the Bayern mission, not the Kafer War.
 
Yes, the closing off is recent. And maybe a response to the Bayern (as it looked at the pentapod homeworld the gods looked back and got a bit nervous). But since the Bayern corridor is clearly stated as being in use there must be a way to it that doesn't intrude on the pentapods.

I'm increasingly leaning towards explaining the route as via the link via DM+39 2376. The original route was via Iota Ursae Majoris, but this alternate route was found when the pentapods acted up.
 
Last edited:
Tell you what: Find a route that works that doesn't go through Pentapod Space, and I'll rewrite whatever needs to be rewritten. Worse comes to worse, it will be the Vogelsperspektiv that visits the Pentapod homeworld, not the Bayern.
 
How about this for a suggestion:

On the outbound trip, the Bayern passed near the Pentapod homeworld and at the time, the Pentapods seem fine with the Bayern passing through.

However, on the return trip, the Bayern was met by a Pentapod floatilla a system out that regretfully informed the Bayern that they wouldn't be allowed near the Pentapod homeworld due to "developments." However, as the original agreement had to be let the Bayern pass by both on the way out and the way back in, the Pentapods had gone to the trouble of paying some exorbriant fee for Trilon to make a very large tugship specifically to tug the Bayern around the Pentapod homeworld (Trilon being selected because they already had experience in designing and testing tugships).

Whatever, the Pentapods didn't want the humans to see the second time, they were willing to pay billions of Lv to push their custom job to the top of Trilon's shipyard schedule...

Of course the conspiracy theorists are having a field day with that one.
 
Never send a human to do a machine's job :-) Now I have made a program that finds the best route to the Pleiades in the HYG map.

To do it it tries to minimize a total cost based on jump length. The cost for < 7.7 ly jumps is just the length, while for a jump of length l > 7.7 it is l*(l-7.7)^3 - it penalizes long jumps where either the Bayern have to use drive trickery or we have to assume dim stars.

1_bayernsol.png

http://www.TravellerRPG.com/CotI/Gallery/index.php?n=266

From Sol, the best path runs to Sirius, up to Austin's world, then a long jump to Pi 3 Orionis, and then a zigzag up to and through the Hyades, a long horizontal to HD 18737 and the straight up to the Pleiades. Changing my cost function doesn't change the route much. I include the star coordinates below.

A cute variation occurs if I start from Neubayern: then it goes off into the 61 Cygni cluster, jumps to the Theta Persei cluster and joins the main route at NN 3241. Starting from Ross 627 also runs off to this route - by going back along the French Arm. I doubt this is the route actually used.

A start along the Latin Finger doesn't sound too weird. Then a tug-possible jump to Pi3 orionis and a mixed set of jumps until HYG 17680, the first place where there is a 15+ ly gap in the data. I'm a bit surprised my favourite corner of Pentapod space wasn't optimal, but that just goes to show that human eyesight is no match for AI (or rather, Dijkstra's search algorithm).

Now we just need to settle on where we want Littleendia to actually be.

Alpha Canis Majoris A distance 8.626703 XYZ -1.600000 8.100000 -2.500000
Ross 614 B distance 5.032892 XYZ -1.600000 12.800000 -0.700000
Austin's World System distance 7.374280 XYZ 2.500000 18.900000 -1.300000
Pi3 Orionis distance 8.223138 XYZ 7.700000 23.600000 3.000000
Ross 41 distance 5.580323 XYZ 4.200000 27.600000 4.700000
DM+10 1032 B distance 6.256197 XYZ -1.100000 30.800000 5.600000
DM+11 878 distance 7.966806 XYZ 4.200000 36.500000 7.300000
Ross 42 A distance 9.100000 XYZ 6.000000 45.400000 7.900000
Gl 201 distance 6.256639 XYZ 7.052868 44.078362 13.924141
AC+19 1165-38 distance 3.229732 XYZ 9.500000 42.800000 15.600000
DM+20 802 distance 6.090977 XYZ 15.300000 41.300000 16.700000
39 Taurus distance 7.034913 XYZ 21.500000 38.100000 17.600000
NN 3232 distance 8.358792 XYZ 29.800914 39.011563 17.965074
NN 3241 distance 5.804439 XYZ 28.842115 40.991695 23.336413
NN 3242 distance 5.146116 XYZ 31.360052 44.608959 25.993084
Wo 9125 distance 6.995121 XYZ 34.087345 50.662318 28.195456
Wo 9127 distance 2.892980 XYZ 35.535249 52.863939 29.389511
Gl 157.1 distance 6.397823 XYZ 33.481070 57.899326 32.759581
NN 3274 distance 9.724798 XYZ 30.053002 65.807001 28.255281
NN 3276 distance 7.883257 XYZ 30.963067 68.130034 20.777244
NN 3302 distance 8.252053 XYZ 28.178917 74.017129 15.709009
Wo 9158 distance 10.871054 XYZ 31.940721 80.921413 8.201712
Gl 173.1B distance 9.077988 XYZ 31.320941 85.731525 15.875599
NN 3334 distance 11.120063 XYZ 20.620439 88.678807 15.191069
HD 32237 distance 7.876864 XYZ 22.649501 87.836787 22.755386
HD 30455 distance 11.721964 XYZ 29.091299 90.473625 32.186970
HD 29150 distance 12.098845 XYZ 36.527680 95.447066 40.332347
HD 284310 distance 9.187433 XYZ 42.745313 88.732337 41.146216
HYG 19962 distance 7.163991 XYZ 45.136098 94.059672 45.296687
HD 28580 distance 8.009035 XYZ 40.182327 98.556176 49.699669
HYG 20724 distance 9.688551 XYZ 45.088147 105.004171 55.012325
HYG 20843 distance 3.916440 XYZ 45.424720 107.880603 57.648869
HD 283668 distance 6.612904 XYZ 48.306371 113.634771 56.126983
HD 27808 distance 7.046719 XYZ 50.245956 113.175286 49.368054
HD 27250 distance 7.467107 XYZ 55.620329 117.885418 47.202771
HD 27989 distance 5.438403 XYZ 53.404322 122.618091 45.696999
64Del2Tau distance 5.871961 XYZ 56.555382 127.167145 43.733112
HD 28205 distance 6.330057 XYZ 56.470896 132.389575 40.156981
HD 28258 distance 5.926055 XYZ 58.078214 136.944729 36.724020
79 Tau distance 7.592266 XYZ 60.550549 144.105733 36.223923
HD 28635 distance 7.801761 XYZ 61.290762 150.729974 40.278426
HD 286900 distance 8.427295 XYZ 59.951874 157.589471 35.569500
HD 29862 distance 6.666372 XYZ 57.197409 163.360047 37.454675
HD 29528 distance 8.702754 XYZ 61.885555 169.124131 41.986181
HD 286839 distance 5.735035 XYZ 67.499587 167.966676 42.169375
HD 286719 distance 11.417050 XYZ 76.028282 166.241795 34.777813
HYG 19484 distance 12.685491 XYZ 86.776964 168.625045 28.476412
HD 286457 distance 11.620735 XYZ 94.145658 163.680212 35.979240
HYG 17680 distance 15.316682 XYZ 108.978103 167.357432 37.017209
HD 22952 distance 14.249383 XYZ 118.552823 171.645037 46.660137
HD 22682 distance 9.963155 XYZ 124.276231 176.310089 53.349260
HD 22481 distance 5.014882 XYZ 125.167572 174.421815 57.908753
HYG 16097 distance 18.136804 XYZ 132.754332 169.798060 73.720319
66 Ari distance 15.646504 XYZ 127.889646 164.344779 87.555407
64 Ari distance 9.469184 XYZ 131.281278 162.564738 96.215300
HD 20327 distance 21.746308 XYZ 147.370799 171.070208 108.118501
HD 19485 distance 8.640878 XYZ 155.042501 167.252135 109.228494
HD 18737 distance 19.650043 XYZ 172.333841 174.555296 115.042063
HD 19503 distance 8.921294 XYZ 168.672148 182.230227 117.739639
60 Ari distance 19.139945 XYZ 167.028361 199.809961 125.128037
HD 21685 distance 20.457919 XYZ 161.521583 212.436282 140.253441
HD 21700 distance 9.484283 XYZ 166.549043 219.137050 144.700461
HYG 16390 distance 14.502172 XYZ 174.743839 230.969433 142.924791
HD 23155 distance 17.146387 XYZ 165.343571 244.486443 138.136893
16 Tau distance 9.915701 XYZ 169.637407 253.409416 137.622443
HD 23410 distance 7.245797 XYZ 171.231057 258.244744 132.466721
HD 23157 distance 8.234756 XYZ 176.605920 261.071626 138.028268
HD 22887 distance 10.636234 XYZ 184.709935 267.209568 141.155580
23 Tau distance 9.142439 XYZ 180.824240 274.041794 145.825296
HD 23642 distance 2.960328 XYZ 179.546417 275.136717 148.260836
25Eta Tau distance 7.406591 XYZ 183.461110 281.118736 150.196865
 
Colin said:
How about 64del2Tau?
Click to expand...

Hmm, HIP 20542/HD 27819/HR 1380. Spectral type A7V absolute magnitude 1.54. A bit hot. According to SIMBAD it is a double star, and it is right in the Hyades. I would expect it to be a bit too young to be Littleendia (the cluster is just 625 my old). But it would have a pretty night sky! One possibility might be that Littleendia actually orbits a dim companion to 64 Tauri.

What about HD 27989, the one just before? Ah, G5V, but variable. It is a BY Draconis variable, with massive star spots and coronal activity changing with its rotation, but less than 0.5 magnitude changes. That might be survivable for a garden world. HD 27250, the one before that, is a G9V with absolute magnitude 5.47 - this is quite close to the description of Littleendias sun. It is also a BY Draconis variable! I think the neighbourhood is a bit unstable: plenty of hot stars, but many are still unreliable. HD 27808 (a few steps before them) is G5V (absmag 5.76) but a double star.

How harsh do you want me to be in my hunt? If you just want a mild-mannered star that doesn't seem to be into a youth gang (ahem, cluster), variable or having unwanted companions, what about HD 29150? G5V, absolute magnitude 4.94. A bit closer than the previous ones but pretty sol-like.

(I'm in awe of the computeriness of Centre de Données astronomiques de Strasbourg after this search :-) )
 
BMonnery said:
Nice, but this is a non-viable route isn't it more than 2 7.8ly+ jumps....
Click to expand...

This is the best we can do using known star data. We know there has to be a lot of dim or unmeasured stars out there that aren't in the catalogue, but the choice is either to give up and say we cannot say anything about the route, or to assume there are enough stars to enable the Bayern to go where it needs to go and plot a likely (if partial) course.

(Something I want to explore a bit is how stable the route is against adding random red dwarves; there are some intriguing stochastic geometry and percolation theory problems here which might actually be worth pursuing for their own sake...)

If I remember right the Bayern could jump 15.4 holes once or twice using disposable drives. If it otherwise can only jump 7.7 ly it will likely not be able to get to the Pleiades: there are likely several necessary mid-range jumps of tug-ship length (given our experience with cluster sizes in nearspace). It makes me think the Bayern had some stutterwarp tug capability.
 
This is the problem, the Bayern, as written, can't get to the Pleiades. There isn't a route. However, she is carrying sufficient disposible drives in the terms of her message drones (which are useless as soon as the first 7.8ly+ jump is made).

Even then we have a problem. Your above route includes 7 jumps not capable even with dropping a drive.

Another approach might be to break the journey into 7.7ly capable groups, and then try and link them. Bear in mind, dropping a drive is actually 100's, even 1,000's of times more expensive, the algorithum might work better if the price above 7.7ly was 2 logs more expensive....
 
A start along the Latin Finger works fine. I guess the Vogelsperspektiv gets a new job.

As for the route, we can fudge it with dim stars. The Kafer Sourcebook took this approach, after all.

I'm going to sit down and see if I can redesign the Bayern tonight, using the 2320AD starship rules. My difficulty here is that my "Flight of the Bayern" is in storage. Can anyone provide me with the stats and general description? A PM would be preferable.
 
Anders said:
If I remember right the Bayern could jump 15.4 holes once or twice using disposable drives. If it otherwise can only jump 7.7 ly it will likely not be able to get to the Pleiades: there are likely several necessary mid-range jumps of tug-ship length (given our experience with cluster sizes in nearspace). It makes me think the Bayern had some stutterwarp tug capability.
Click to expand...

Right you are.

The Bayern carried additional "offline" jump drives that could be discarded to bridge a 7.7+ ly gap once in the round trip. It would drop a drive crossing it the first time, then drop another coming home.

Though you'd think that by 2300 we'd have much better optics and so on so they'd be able to chart a course without having to "guess" about "drop stutterwarp" points...
 
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