Learn Traveller in Under 60 Seconds

[CyborgPrime]

Astrogation: Traveller RPG Skills in 60 Seconds ​

Ever wonder what the Astrogation skill actually does in Traveller?
From plotting safe jumps through Jumpspace, to slingshotting around a gas giant, this quick breakdown gives you everything you need in under a minute!

Watch here:

 

[Spinward Scout]

Got any Astrogation examples with good and bad modifiers?

 

[Commander Truestar]

Got any Astrogation examples with good and bad modifiers?

So, my players were on an "assignment" with multiple outcomes departing from the Regina system to the Arden system
The jumps to Extolay to Tremous Dex to Arden could have been standard.
But, Tremous Dex is a pirate den surrounded by a jump shadow of 24 Hours 45 min due to the world being in orbit of a Gas Giant.

So, giving someone over a day to "welcome you" to a pirate den being a bad idea, they decided to look for what is referred in the "Battletech world" as a "Pirate Point": a point in space where gravitic and other interstellar energy forces interact to cause gravitic null points in a given space.

These would be points which, when identified by an Astrogator, would allow them to plot a jump point "Within" the 100 D limit.
As in "Waaaaay" within the 100d limit.

So, using the best data they could get in and from the Extolay port started a task chain.
1) Get cooperation from Extolay port to get their most up-to-date data 2D6+Admin+ 1/2 Carousing(making port workers buddies)+ bonus for Charisma (a stat I use IMTU) - "Outcome Uncertain" Difficulty: "Average" to "Difficult" (use flux dice to decide)

2) [Optional] Get cooperation from other ship crews in Extolay port to get their most up-to-date data 2D6+ Carousing(making port workers buddies)+ bonus for Charisma (a stat I use IMTU) - "Outcome Uncertain" Difficulty: "Average" to "Difficult" (use flux dice to decide)

3) Determine an established point in the Extolay system from which to jump and plot a course to reach that point at Zero Vee:
2D6 + Pilot Outcome: Obvious Difficulty: Routine

4) Plot the jump with the following factors:
----A) Plot the location of bodies within the Tremous Dex system on which the gravitics and other factors depend:
2D6 + Navigation + (Between +2 and -2 dependent on the outcomes of 1 and 2 above) Outcome: Uncertain Difficulty: Formidable
----B) Identify potential null grav points in the Tremous Dex system to which a jump plot can be computed:
2D6 + Navigation + (Between +2 and -2 dependent on the outcomes 4 A above) Outcome: Uncertain Difficulty: Formidable

5) Hazards:
----A) Incorrect plot results from the process above: Initiate the GM's choice of Misjump, system failures on arrival, critical systems failures on
arrival or Misjump with system failures. (I once had my team face critical systems failures including life support WHILE in a misjump)

----B) Presence of unknown objects at or near the jump coordinates causing likely energy fluctuations that would blast the arriving ship with
energy feedback and failures (Severity up to the GM)

I can expand on this if this were not just off the cuff but I'll cut this short for now

 

[Badenov]

So, my players were on an "assignment" with multiple outcomes departing from the Regina system to the Arden system
The jumps to Extolay to Tremous Dex to Arden could have been standard.
But, Tremous Dex is a pirate den surrounded by a jump shadow of 24 Hours 45 min due to the world being in orbit of a Gas Giant.

So, giving someone over a day to "welcome you" to a pirate den being a bad idea, they decided to look for what is referred in the "Battletech world" as a "Pirate Point": a point in space where gravitic and other interstellar energy forces interact to cause gravitic null points in a given space.

These would be points which, when identified by an Astrogator, would allow them to plot a jump point "Within" the 100 D limit.
As in "Waaaaay" within the 100d limit.

Is this different from a standard Lagrange Point mathable by anyone with current astrogational information? I can see that getting recent system data is important for current Lagrange Point navigation, you don't want to try to thread that needle using old data, and the path to that point can be kind of important, but I can't see it being particularly hard to obtain unless the locals tow moons around to change the points' location. The Earth-Sun Lagrange points are just outside the 100D radius of Earth, but it seems reasonable that there are Lagrange Points inside 100D depending on specific system geometry. (https://en.wikipedia.org/wiki/Lagrange_point).

Though it seems to me that ambient gravity would always pull you out of jump before you reach this null? Presumably there's a curve of equi-gravitational points you can fly into the Lagrange Point? That's probably something that changes rapidly over time as the planet orbits, necessitating the recent system nav data.

 

[Grav_Moped]

Though it seems to me that ambient gravity would always pull you out of jump before you reach this null? Presumably there's a curve of equi-gravitational points you can fly into the Lagrange Point? That's probably something that changes rapidly over time as the planet orbits, necessitating the recent system nav dat

Totally agree. Trying it outbound? Yeah, miss the spot outbound and you're in a world of hurt.

 

[Commander Truestar]

Is this different from a standard Lagrange Point mathable by anyone with current astrogational information? I can see that getting recent system data is important for current Lagrange Point navigation, you don't want to try to thread that needle using old data, and the path to that point can be kind of important, but I can't see it being particularly hard to obtain unless the locals tow moons around to change the points' location. The Earth-Sun Lagrange points are just outside the 100D radius of Earth, but it seems reasonable that there are Lagrange Points inside 100D depending on specific system geometry. (https://en.wikipedia.org/wiki/Lagrange_point).

Though it seems to me that ambient gravity would always pull you out of jump before you reach this null? Presumably there's a curve of equi-gravitational points you can fly into the Lagrange Point? That's probably something that changes rapidly over time as the planet orbits, necessitating the recent system nav data.

Yes,
Thanks to my involvement with various astrophysical projects in the past, I came to understand trans-systemic gravitational influences.
Despite the distance between us and the Alpha Centauri system, those stars and even exoplanets(discovered and theoretic) "do" affect the bodes in our solar system. That said, trans-systemic forces are constantly shifting on a local(nearby systems) and distant scale.

In addition, there are a great many bodies in our system that many researchers sadly consider insubstantial.
So, a "proper" mapping of orbital mechanics is something many labs can't correctly create. This was even an issue in the brief years I worked for Dr. Sagan. So, even at the top, with (temporarily - Yes, this is sour grapes) reasonable funding, results "today" are highly questionable.

So, "MTU" includes that variable nature of gravitic "nulls" which appear or fade based on the configurations of all forces acting on a given system.
Because of that, there are the standard La Grange points as well as points which exist only while the correct configurations exist.
An example would be the three stars of the Alpha Centauri system aligning for a week when Sol's outer gas giants are at apogee so their still
considerable in-system gravitc influences are reduced slightly. This could - theoretically - allow Terra and Mars to pull other bodies into
unusual configurations which "might" create grav-nulls near Terra's current position in her orbit.
The skill level needed to achieve such a plot is high. It can only be "dreamed of" at skill level 4.
Your Level 5 Nav officer can do it with difficulty and high risks which are less of a threat(but still there) for a Nav-6 officer

And, to address the comment,

it seems to me that ambient gravity would always pull you out of jump before you reach this null?

I defer to the accepted Laws of Physics.
["Accepted" because we are always testing, learning and know so much more than we did when Dr. Einstein attempted to produce a Unified
Field Theory.]
The growing affects of an existing gravitational body which an in-jump vessel is approaching is a force which can be quantified.
As a result, the "pressure" to violate the stability of a jump field and force the craft out of jump can be plotted and managed by a navigator of the appropriate skill. So, a Navigator with the proper skill can manage that growing force and the power fed to the jump field.

While the Traveller rules (and fiction based on them -Largely based on the DGP Operator's Manual) suggest the Jump Governor feed a steady stream of power to the lanthanum grid from the zuchai crystals, navigators IMTU can "manage" this power feed to also manage that counter-force.