Spaceship based telescopes

[Anthony]

Originally Posted by David L Pulver

I'm more concerned with _overall_ weight scaling for all the optical systems rather than just the mirror itself...

Yeah, still goes up that way. Volume will pretty much go up with the cube, but the sensor will be increasingly hollow.

Originally Posted by David L Pulver

Incidentally, overall weights for active sensors like radar seem to also scale with about the square of the range.

Radar is funky. It's about order 1/4 in both power output and collector area, so overall about the 1/2 power.

[weby]

I would not thing the in plain sight modifier as being standard for many things you try to see with spy satellites.

My view after seeing some commercial satellite pictures that are supposed to be worse than the spy satellite ones is that even a layman like me without any special skill can see things like a car clearly(and to separate something like a van from a subcompact) and notice individual people in open view fairly well. I think the images in question were about 0.6 meters/pixel though not sure anymore. That is without all the bonuses for analysis equipment or taking extra time or whatever. That is likely the +10 effect.

The computer support, highly trained people, extra time and all that is for the hidden things where you do not get the +10(and of course to understand what is different about one industrial plant to next as example).

[Fred Brackin]

Originally Posted by David L Pulver

I'm more concerned with _overall_ weight scaling for all the optical systems rather than just the mirror itself...
.)

The mirror dominates all other components in large telescopes and telescopes have always been mostly hollow.

I don't think you can get a realistic rule that scales for binoculars
and small LLTVs and thermographs and astronomical telescopes. The things that change when you scale up don't change in a homogenous manner.

[Ulzgoroth]

Originally Posted by weby

I would not thing the in plain sight modifier as being standard for many things you try to see with spy satellites.

Depends what you're trying to spot. Camouflaged facilities, probably not. Counting ships in a port and tanks or trucks in a parking area, very possibly.

Of course, the Hubble is not a spy satellite.

[Anthony]

Originally Posted by weby

I would not thing the in plain sight modifier as being standard for many things you try to see with spy satellites.

Generally speaking, you get the most realistic results from GURPS perception by just giving the 'in plain sight' modifier to all vision rolls.

[Ulzgoroth]

Originally Posted by Anthony

Generally speaking, you get the most realistic results from GURPS perception by just giving the 'in plain sight' modifier to all vision rolls.

Even for quick contests against hiding skills, and noticing things that you aren't looking for?

(Two of the three cases where Enhanced Senses specifies not to use it. The third is, if I understand correctly, for rolls to notice something whose significance is non-obvious and would require a separate roll to appreciate.)

[Anthony]

Originally Posted by Ulzgoroth

Even for quick contests against hiding skills, and noticing things that you aren't looking for?

Well, maybe not to Holdout, but then, holdout modifiers don't match size modifier anyway. Noticing things you aren't looking for may have a roll to realize the thing matters, but assuming that roll is trivial then yes, +10 is fine.

[David L Pulver]

Originally Posted by Fred Brackin

The mirror dominates all other components in large telescopes and telescopes have always been mostly hollow.

I don't think you can get a realistic rule that scales for binoculars
and small LLTVs and thermographs and astronomical telescopes. The things that change when you scale up don't change in a homogenous manner.

Nonetheless, I must indeed cover robot eyes to giant telescopes...

As muttered already, I'm inclined to scale optical systems in a roughly linear manner at low magnifications/bonuses but use square of mag for weight at later levels as the simplest compromise even if it's not perfect.

The main problem is I can't figure out a way to make HIGH TECH's suggestion of Telescopic Vision as high as 10-15 (up to 32,000x magnification) for TL7 spy sats work unless I made the scaling *linear* with magnification (Given that Anthony makes a good argument that t his isn't really logical, and about 9-10 levels is better, perhaps I shouldn't...) Square of 32,000 gets rather impossibly high...

I'll probably reluctantly have to say that in Vehicle Design at least the values are about half to 2/3 what HIGH TECH says. I don't really like to do that, but it has the advantage of actually better matching the numbers in SPACESHIPS and UT, so it's not really a retcon.

[David L Pulver]

Originally Posted by Ulzgoroth

Depends what you're trying to spot. Camouflaged facilities, probably not. Counting ships in a port and tanks or trucks in a parking area, very possibly.

Of course, the Hubble is not a spy satellite.

There is some anecdotal evidence that a lot of technology is rather similar, the optics are similar size, and NASA histories indicate technology transfer occurred between the Hubble and KH-11.

My current working option for visual light TV sensors based on this discussion at TL8 is:

Up to 16x magnification: weight = magnification/16.
Over 16x magnification: weight = (magnification/16) squared.

* You can then spend extra money to halve the weight, or take a big discount but double the weight.
* Assumes Tunnel Vision. Double weight for 120-degree restricted vision; 3x weight for human vision.

Thermal imaging sensors are about 4x heavier (effectively on level of telescopic vision worse.)

Night Vision are complex (Anthony has argued they should be much worse than GURPS portrays them; Kromm has disagreed, I think)
but probably 1-2x heavier? and costlier; I guess it mostly depends on the type of night vision

Thoughts?

[weby]

Originally Posted by Anthony

Generally speaking, you get the most realistic results from GURPS perception by just giving the 'in plain sight' modifier to all vision rolls.

Yes, thus I have a house rule that has "no time" vision rolls be +0 and if you take the full second to look, you get the +10, so for example in the heat of the combat you will likely miss many things not related to your target, but if you actually concentrate on looking you are less likely to do so.

But in this case we are talking about the actual rules, not house rules.

Thus to get the values that correspond to the normal rules the bonus needs to be higher.