Quote from Bladerunner :

Not really sure...I'll have to ask my mate Paul Atriedes if he or Duncan knows the answer...
I feel a right Herbert sometimes!!

Desert, there is another tip for you

Quote from JTbo :

but how about when you plot course wrong, virtual space shows you are at jupiter even you don't see any planets nearby, then what?

then chances are you got imperial and metric units mixed up

Quote from (SaM) :

Yes there is, but in my context, it's so small it's irrelevant.

try and play orbiter for a while ... youll find that gravity is anything but irrelevant no matter where youre at

Quote from Aquilifer :

In one scifi book they were not allowed to have computers. Instead they harvested some 'spice' from a surface of a planet (called Arrakis) and spaceship pilots used this 'stuff' to improve their thinking and allowed them to navigate between stars w/o computers (remember what book and computer game? Does sand worms help at all? )

wasnt that only to see into the future far enough to safely maneuver around objects in deep space at light speed ?

Quote from JTbo :

I remember some of that book

Good explanation of navigation, thanks.

How about electro magnetic radiation of stars, you could regonize star by that when you know that you should be near some star so you can compare that signature to data you have and find out if you really are close to proper location.

Of course charting of space will be going on at some point I believe, putting those stars more accurately on place.

Actually that comparing of the signatures is an interesting idea... didn't think about it. There is just one thing... stars are not unchanging. It's signature changes with it's age, but for human lifetime they can be considered often constant. Of course you would need to update the chart everytime there is a supernova explosion or some other radical changes (like neutron star or black hole mutilates a normal star). Even in very early or late in their life cycle there can be rather fast (but in a way normal) changes.

Then there are these variable stars (Mira type and Cepheid variables). How that periodic size and temperature changes affect should be saved too.

I do not know how accurately you could tell two stars different by looking their spectra (if they are very similar). So are they as good as human finger prints or iris? Not at least in the way that they are not constant, but together with coordinate information you should have enough data for human lifetime... I think.

As a classification example: Sun is now G2V. In future it could become K2IV and M1III (temperatures pulled from a hat, but something like that) and in the end (after it died) e.g. DO1 (kind of a white dwarf).

Quote from Shotglass :

...
wasnt that only to see into the future far enough to safely maneuver around objects in deep space at light speed ?

Could be. Cannot remember anymore so well. Maybe we should ask Spice Girls how it was?

JTbo,
if you travel to alpha centauri, you can measure the speed by changes of the visible spectrum, and the position by the visible sizes of the 4 nearest stars. There is a lot of information. Unless you want to stop somewhere in the middle of interstellar space for a roadside picnic, there is enough info.

If you are very interested, you may want to try Orbiter space simulator. Though, it is very complicated, I gave it up. For a start you may try to orbit around the Earth in X-Plane's Discovery Shuttle, land and take off into space manually controlling it. I managed to stabilize height and make a speed error less than 1 Mach

Quote from Aquilifer :

Actually that comparing of the signatures is an interesting idea... didn't think about it. There is just one thing... stars are not unchanging. It's signature changes with it's age, but for human lifetime they can be considered often constant. Of course you would need to update the chart everytime there is a supernova explosion or some other radical changes (like neutron star or black hole mutilates a normal star). Even in very early or late in their life cycle there can be rather fast (but in a way normal) changes.

Then there are these variable stars (Mira type and Cepheid variables). How that periodic size and temperature changes affect should be saved too.

I do not know how accurately you could tell two stars different by looking their spectra (if they are very similar). So are they as good as human finger prints or iris? Not at least in the way that they are not constant, but together with coordinate information you should have enough data for human lifetime... I think.

As a classification example: Sun is now G2V. In future it could become K2IV and M1III (temperatures pulled from a hat, but something like that) and in the end (after it died) e.g. DO1 (kind of a white dwarf).

This would only work in local space where you have these stars mapped out and indidually classified in the ~Auto pilots database. But if you still stuck Billions of light years away from source then it could match up those stars it see's with anything. Looking at it, it may have the right star (for example: if you overshot and where now looking at it from direct opposites) but it still couldn't give you an accurate position without knowing how and where it came from and got too. There would be countless billions white dwarfs, pulsars, Binary's, Supergiants out there that an auto pilot would take it's information from so it could give many positive matches if put into a strange local. But say you travelled from here to Alpha making notes as you went you could easily increase your database of local knowledge by simple triangulation. Something we can only do in an interstellar situation at the moment by waiting every 180 days to take a second set of readings.

To make an instellar auto pilot work effectivily looking a the stars would be only a small fraction of the information needed. Vastly more important would be the 'I know where I've been' thing I said earlier. It's how they found the america's donchaknow

.....space is stretching continuously ie: the distance between celestial objects is increasing at the same time as they move through the universe (the universe itself is stretching). Additional forces from the Great Attractor and other influential manifestations throughout the universe also play a role in mixing things up. No permanent 3D "atlas" can be concieved without taking into account all of the many forces at work. The presence of worm holes and black holes and the density of dark matter (which is not uniform when considering a "small" slice of the universe) also play upon the movement and location of objects.

The sky that exists above a new born baby tonight will look different than the one above their grave if they are fortunate to live a full life.

Yes. Well, I was thinking to store the stars galaxy wise. In the beginning not even all the stars but the closest ones. Currently the distance data is way too inaccurate to even those behind the milky way core not mention other galaxies (we actually cannot see many of them behind the clouds around the core). So I wasn't even dreaming about other galaxies. Of course this would get constantly more accurate as you travel to other stars and the distance/location data becomes more accurate.

The expansion of universum can be seen well between galaxies, but in a single galaxy the stars rotate around the galaxy core mainly. Sometimes their orbits may be altered by nearby objects (like other stars and black holes etc) so the database would require some occasional updating. But same way you need to update normal maps.

About to find out where you are: There are things you can measure. (let's assume we know we are in the same galaxy) The distance and direction to galaxy core (huge margin for error if it is far). The finger print for nearby stars and their positions. With those you could limit the search to database, but there is at least one problem. There are 200e9 stars in Milky way, so we need lots of storage capacity and computational power to process such amount. If you dream to keep all of them, some kind of automated data input/update system would be needed.

It is indeed easier to know where you are and just aim for the target system and let the auto pilot keep the heading. But I think the idea was to have some kind of general map.