Alternative compass implementation

[Wildeblood]

The space compass doesn't actually work like a compass at all. A compass allows you to know which direction you are headed compared to fixed cardinal directions. It's up to you to know whether heading in that direction will take you to a useful destination. The space "compass" is actually a direction finder, comparing your heading to a destination point.

It occurs to me that one could create an actual compass by the following method:
1. first invent two new cardinal directions;
2. then instantiate six objects with cardinal beacons;
3. position them at ludicrous distance, in each of the cardinal directions;
4. remove all other beacons.

Would anyone want to do that? I doubt it, since it would make game-play harder to not have the direction finder. It just occurred to me that it was possible.

[Diziet Sma]

Interesting concept, but what practical use would it be?

[Tricky]

Possibly to have a compass like this...

You could then practice getting Gimbal Lock! (Sorry Gimbal )

[Commander Wilmot]

I don't want to hijack your idea, but we do not have a map of the system we are in, because it is randomly generated, so knowing that we are facing an arbitrary direction, "solar north" for lack of a better word, doesn't help much. The player would have no idea of where the stations are, except for the main one and that only vaguely, somewhere around the orbit of the planet is a big place. Could I propose a modification of your concept?

Something similar to this might be to have an expansion to the advanced space compass that displays your heading and pitch on the HUD. That way you can dock and still find something in system that isn't marked by a beacon, like a rock hermit or and abandoned ship, after you have dropped your cargo/refueled/repaired, etc. I have sometimes done this by guessing the angle I am coming into the main station aegis at, and then relaunching and heading at the same angle away from the station. It is a bit hit and miss, but you can sometimes find things again.

If you added beacons, two at each edge of the x,y,z axes of far out at the edges of the system, then maybe you could use their coordinates to calculate a heading and pitch based on which ones you are facing towards and what angle you are aimed at between them. For example, if you are faced to heading 0, pitch 0 at the witchpoint beacon, then you are directly facing SPS, Solar Positioning System, beacon 1. If you pitch up half way between beacon 1 and the beacon above the solar system, then you are at a 45 degree angle and therefore heading 0, pitch 45.

I don't know whether it is possible to do this in an oxp, it seems like it would be a pain. But maybe this system would give you the better sense of direction you seem to desire, albeit though it be with very limited use in gameplay that's mundane.

[Wildeblood]

Commander Wilmot seems to have understood exactly what I was thinking of, and probably explained it better than my cursory way.

Being able to find your way back to interesting locations, without adding beacons to every object in the system, would be an advantage. But really the only use for such a system, with regard to game-play, would be to add an intermediate level of difficulty between the basic compass and the direction-finding advanced space compass we have now.

[Diziet Sma]

Ahh.. so it's basically a more complicated way of doing what the  Tracker OXP does, or (although not quite so well as the Tracker, however) the  ETT Homing Beacon.


How the Tracker works:

Once purchased, it is selected by using the "shift-n" key, and then activated with the "n" key (under standard keyboard configuration). This will transfer the current target lock (be it an ident-lock or a missile-lock) to the system. It can then be viewed on the ASC by cycling through to the "T" indicator. Note that a target lock is required before the system can track the entity, so cloaked ships and certain other entities cannot be tracked.


The system has capacity to store five lock-ons.

[fronclynne]

If you assume that the witchpoint, sun, & planet are all in the plane of the ecliptic (but this assumes that the sun doesn't rotate, which I guess may well be in Oolite) the display of your cardinal points should be possible without having to set arbitrary beacons (though not necessarily trivial).

Aslo, in the framework of a (hypothetically) revolving system would there be some better system than Euclid's?

[superbatprime]

How the Tracker works:

Once purchased, it is selected by using the "shift-n" key, and then activated with the "n" key (under standard keyboard configuration). This will transfer the current target lock (be it an ident-lock or a missile-lock) to the system. It can then be viewed on the ASC by cycling through to the "T" indicator. Note that a target lock is required before the system can track the entity, so cloaked ships and certain other entities cannot be tracked.


The system has capacity to store five lock-ons.

That's neat, I'll probably grab that.
Does the tracker retain locks established prior to docking or does docking clear the system (for tagging stuff on the way in to investigate after delivering cargo etc)?

I do like the idea of the SPS though (or something similar), that allows you to calculate the location of any point in space not just objects.
What practical use it would be other than to give us fun math (yay?) to play with I don't know, but sometimes stuff is just cool because it's cool.

I would totally install an oxp of this nature just because it would make me feel like a hardcore navigator.

[Diziet Sma]

That's neat, I'll probably grab that.
Does the tracker retain locks established prior to docking or does docking clear the system (for tagging stuff on the way in to investigate after delivering cargo etc)?

It retains the lock until you leave the system, or, if the target docks, lands on a planet/moon, enters witchspace or is destroyed then the lock is also lost.

[superbatprime]

So it locks until the target no longer exists basically, can't ask for more than that, nice one, sold.

[RockDoctor]

Not particularly intending to resurrect this "dead thread", but it turned up when I was looking for something else. But in case someone else comes across this, while in the position of thinking about position systems ...
Fronclynne here has a fundamental error in his understanding of celestial dynamics :

If you assume that the witchpoint, sun, & planet are all in the plane of the ecliptic (but this assumes that the sun doesn't rotate, which I guess may well be in Oolite) the display of your cardinal points should be possible without having to set arbitrary beacons (though not necessarily trivial).

Aslo, in the framework of a (hypothetically) revolving system would there be some better system than Euclid's?

The rotation state of a star isn't, fundamentally, strongly related to the star systems "fundamental plane" - which in itself isn't well defined. Terrestrial celestial mechanics refers everything to the plane of the Earth's orbit around the Sun, which is, coincidentally not that different to the orbital planes of the other planets (degrees inclination : Me 7, V 3.4, E 0 [Moon 5.1], Ma 1.9, Ju 1.3, Sa 2.5, U 0.8, N 1.8, then the small stuff is, literally, "scattered"), but as we've gained understanding of exoplanet systems, we see a lot more variation in inclination, including several cases where some planets orbit in a direction retrograde to other planets in the same system. People have even worked out sane-sounding ways to evolve from a rational-sounding "everything developed from a debris cloud collapsing onto one plane of angular momentum" model of planet formation, through sane (-ish) sounding interactions, to end up with one retrograde planet (i.e orbital inclination between 90 and 180 degrees to the rest of the system). Truly, the universe is weirder than we expected. Or in the vernacular, "who ordered that?"

So, if someone is rationally designing a planet system (or setting parameters for a random-system generation), the sane way to go would be to put everything orbiting normally, close to one plane, but if you want to throw in a curve retrograde ball every so often, that's within the bounds of our Universe. The betting money would go for having most big stuff (planets, gas giants in particular) close to one plane, and the small stuff (asteroids, comets) much more randomly distributed. But that's definitely not a hard restriction. There's even one real system with a major planet inclined at about 90 degrees to everything else - which sounds like a recipe for wild interactions and eventual impacts. But it seems to be stable. Well, stable enough for us to find it in the first 5000-odd examples.

On defining "available in every system (that would appear in the Ooniverse)" points for some absolute position frame, I'd throw in these three "fixed" points for the compass to identify : The star (doh, but in the event that someone builds a binary or higher system, the MOST MASSIVE star) as the zero point for the coordinate system. The administrative capital planet of the system (allowing for multiple inhabited planets in one system) to define the "X" axis (which technically makes this a coordinate system that is co-rotating with the administrative planet - make up your own justifications for that). Then to define the system's "fundamental plane", identify the trailing Lagrangian point in the star-administrative capital system, which in polar coordinates would be at point r=1 "AU", theta=(minus)60 "degrees" and phi=0 degrees.
Does the core engine scale orbital radii to the "Prime" planet of the system - I can't remember. THeres some fudging of "km" and "Oo-astronomical Units", isn't there?

If you want to populate an unoccupied system (isn't there a system whose star went nova and destroyed the inner planets in Galaxy 4?), choose the second largest body of the system (normally the largest gas giant, but ... binary stars!? ) as the anchor point for the reference system instead of the administrative capital.

I wonder if the core system programmers have looked at binary star systems. I'm thinking in particular of the Alpha Centauri system, where "Alpha" is a binary of two near-solar size stars separated by a distance varying (Kepler, ellipses!) by a Saturn-like spacing at perihelion and a Pluto-like spacing at aphelion. (Orbital period 79-odd years.) That allows for stable orbits for anything closer to the "A" star than about a Mars-orbit and around the "B" star ... some stable orbits, but I forget the paper details. I'll have to re-read it - which means re-finding it.. Then there is Proxima Centauri, which is a runt of a star out at about 430 time the A-B aphelion separation, but still gravitationally bound.

Maybe I should have tracked down a "core game engine" thread for this. But I'd better un-pause my passenger delivery run into Bionus. Whinging passenger is moaning about the flight time. (That happens a lot more since a recent OXP update. That OXP is going to need to add a Bounty-style "lifeboat, bag of food, sextant and one oar" option to terminate a passenger run!

[Cholmondely]

On defining "available in every system (that would appear in the Ooniverse)" points for some absolute position frame, I'd throw in these three "fixed" points for the compass to identify : The star (doh, but in the event that someone builds a binary or higher system, the MOST MASSIVE star) as the zero point for the coordinate system. The administrative capital planet of the system (allowing for multiple inhabited planets in one system) to define the "X" axis (which technically makes this a coordinate system that is co-rotating with the administrative planet - make up your own justifications for that). Then to define the system's "fundamental plane", identify the trailing Lagrangian point in the star-administrative capital system, which in polar coordinates would be at point r=1 "AU", theta=(minus)60 "degrees" and phi=0 degrees.
Does the core engine scale orbital radii to the "Prime" planet of the system - I can't remember. THeres some fudging of "km" and "Oo-astronomical Units", isn't there?

I'd have thought that the ideal 3 points would be the star, the planet and the witchpoint (and probably easier to programme too - only cim's SOTL Exploration oxp does anything with Lagrange points).

But surely, if we had something like this, could we not manage to have a decent map of the system showing known rock hermits, etc? And this could then be used by other OXPS which currently only display distances (Docked F4 screen's Galactic Almanac, Market Inquirer's In-system distances &
Sun Gear's System Data Sheet. And ditto for GalCop Missions' Bulletin Board. And the various Taxi/Delivery OXPs).

[RockDoctor]

I'd have thought that the ideal 3 points would be the star, the planet and the witchpoint (and probably easier to programme too - only cim's SOTL Exploration oxp does anything with Lagrange points).

But surely, if we had something like this, could we not manage to have a decent map of the system showing known rock hermits, etc? And this could then be used by other OXPS which currently only display distances (Docked F4 screen's Galactic Almanac, Market Inquirer's In-system distances &
Sun Gear's System Data Sheet. And ditto for GalCop Missions' Bulletin Board. And the various Taxi/Delivery OXPs).

If you've got 3 points (to define a plane), and two directions (star-planet and star-LP) to define a sense of coordinates, then you can map things "relatively" easily. Otherwise, you're in "Mappa Mundi" quality of mapping - an aspiration to map and reality being associated.
I don't know if the witchpoint has any geometrical relationship to the star or planet. I've always taken it to resemble the "Crazy Eddy" point or "Alderson thermonuclear equipotential point" in Pournelle's "Co-Dominion" universe. The thermonuclear ignition of a protostar in the "Moat Around Murchison's Eye" (US : "The Gripping Hand") moves the Alderson points and creates a new one with plot consequences. Since the two books in this universe co-authored by Pournelle and Niven appeared at about the time Bell & Braben were creating Elite, and there are definite resemblances, that's my 10 c€ worth. Since the witchpoint is potentially moveable w.r.t. both star and planets in the event that a star turns on (or turns off, explosively, per the nova I mentioned), I opted to not use the witchpoint. But yes, it's a definite possibility - depends on what universe physics you want to hand-wave.
I picked the trailing Trojan point because if you're shuffling asteroids around and using the Trojans as a staging area before moving them towards the planet for use as construction materials, then you've got 300 degrees of the orbit for debris from a collision to disperse in the event of undesired events. If you gathered your materials at the leading Trojan point, you've only got 60 degrees of dispersion before you start landing debris on your planet. Since storing materials at a Trojan point requires you to fairly closely match velocity and orbit with the planet, it seems a worthwhile way to go. But that's my imagination, which one day I might commit to (e-)paper.
Regardless of the in-universe story, Lagrange points are a real thing - which never hurts for immersing the addicts in the story.

--

On the subject of things falling out of the sky onto people's/ insect's/ lobstoid's heads, the Minor Planets Mailing List cares about such things, and posted a "wear a pointy hat" notice yesterday evening about the ULA Vulcan launched "Perigrine" spacecraft, whose internal propulsion has gone wonky :

Mon, 15 Jan at 03:22
Hi Bill, all
It seems peregrine has stopped leaking and is following a (mostly) newtonian orbit. My slightly-over-2-hour arc suggests an impact somewhere in South America in the morning of January 17 UTC (around 10:00 give or take a couple hours). The orbit is currently too uncertain to even say if it will impact in the Atlantic, Pacific, Brazil, or Peru, but it seems it's definitely somewhere around there along a line at 10-12 degrees south.

So, anyone you know about 10~12° South, tomorrow morning is good for speleology or re-coating the sewer pipes. About 2 hours of uncertainty, which translates to ~30° longitude.

[RockDoctor]

On the subject of things falling out of the sky onto people's/ insect's/ lobstoid's heads, the Minor Planets Mailing List cares about such things, and posted a "wear a pointy hat" notice yesterday evening about the ULA Vulcan launched "Perigrine" spacecraft, whose internal propulsion has gone wonky :

Astrobotic shuffled the timing by a couple of hours, and dropped the debris (let's remember that not littering the space ways still implies littering the planets) somewhere in the general vicinity of Tonga.