Seeing Planets From a Distance

"Let us create vessels and sails adjusted to the heavenly aether, and there will be plenty of people unafraid of the empty wastes." — Kepler
The Book-House: Find Spelljammer products.

Moderators: Big Mac, night_druid

Post Reply
User avatar
Man in the Funny Hat
Hobgoblin
Posts: 74
Joined: Fri Jan 22, 2010 4:03 pm
Gender: male
Location: The Inland Empire
Contact:

Seeing Planets From a Distance

Post by Man in the Funny Hat » Wed Sep 11, 2019 3:26 am

I realized I was going to need something like this in my upcoming campaign and while I MAY have done something like it before it's not "on file", so...

Planet
Size Distance it can first be seen
J 128 ODS*
I 32 ODS
H 8 ODS
G 2 ODS
F 1 ODS
E 8 IDS
D 4 IDS
C 1 IDS
B 2m Miles
A 200k Miles or less

* Barring a ridiculously large sphere, it can always be readily seen from anywhere in a sphere.

ODS – Outer Display Space; 1 space = about 400m miles
IDS – Inner Display Space; 1 space = about 20m miles

I came up with this by noting that in the real world we can just begin to see Jupiter and Saturn (both size G) from Earth with the naked eye and any amount of magnification makes it easy to see they are not just bright stars. Saturn is very roughly 800 million miles from Earth, or about 2 spaces on the outer planetary display. After that I just fudged it. It's almost certainly WAY off but it at least looks right enough to suspend disbelief.

Jaid
Fire Giant
Posts: 1184
Joined: Tue Jun 17, 2008 4:26 am

Re: Seeing Planets From a Distance

Post by Jaid » Wed Sep 11, 2019 6:09 am

should probably account for brightness/reflectiveness to some extent. a giant disco ball in a sphere with a very strong fire body nearby might be visible from much further away than usual. and of course, a fire body itself will be more visible than normal.

User avatar
AuldDragon
White Dragon
Posts: 2225
Joined: Mon Oct 06, 2008 2:28 am
Gender: male
Location: Silver Spring, MD
Contact:

Re: Seeing Planets From a Distance

Post by AuldDragon » Wed Sep 11, 2019 6:29 am

I generally ignore real-world optics for Spelljammer, for the primary reason that entering a sphere and seeing the (big) planets laid out in dazzling display is so much more interesting and evocative than telling players they basically can't see anything except for a few dots and blackness.

It has the added benefit of making space combat with mile distances and accuracy more reasonable. It is the opposite of the passenger side mirror message: "Objects in Spelljammer appear closer than they are."

Jeff
Let's Play Old Games with AuldDragon (Youtube) | My 2nd Edition Blog
Monster Mythology Update Project | Spelljammer Livestream Campaign
"That sums it up in a nutshell, AuldDragon. You make a more convincing argument. But he's right and you're not."

Jaid
Fire Giant
Posts: 1184
Joined: Tue Jun 17, 2008 4:26 am

Re: Seeing Planets From a Distance

Post by Jaid » Wed Sep 11, 2019 7:44 am

fun fact: there is a wizard spell that focuses air into a lens to allow you to see further. it would be pretty funny if air envelopes naturally formed such a lens :P

User avatar
Big Mac
Giant Space Hamster
Posts: 25116
Joined: Sun Jun 15, 2008 3:52 pm
Gender: male
Location: London UK
Contact:

Re: Seeing Planets From a Distance

Post by Big Mac » Wed Sep 11, 2019 12:16 pm

Man in the Funny Hat wrote:
Wed Sep 11, 2019 3:26 am
I realized I was going to need something like this in my upcoming campaign and while I MAY have done something like it before it's not "on file", so...

Planet
Size Distance it can first be seen
J 128 ODS*
I 32 ODS
H 8 ODS
G 2 ODS
F 1 ODS
E 8 IDS
D 4 IDS
C 1 IDS
B 2m Miles
A 200k Miles or less

* Barring a ridiculously large sphere, it can always be readily seen from anywhere in a sphere.

ODS – Outer Display Space; 1 space = about 400m miles
IDS – Inner Display Space; 1 space = about 20m miles

I came up with this by noting that in the real world we can just begin to see Jupiter and Saturn (both size G) from Earth with the naked eye and any amount of magnification makes it easy to see they are not just bright stars. Saturn is very roughly 800 million miles from Earth, or about 2 spaces on the outer planetary display. After that I just fudged it. It's almost certainly WAY off but it at least looks right enough to suspend disbelief.
Thanks for sharing this.

I think that people might want to tweak this a little (for reasons that Jaid suggested and maybe more) but this is a brilliant way to kick of the discussion.
David "Big Mac" Shepheard
Please join The Piazza's Facebook group, The Piazza's Facebook page and follow The Piazza's Twitter feed so that you can stay in touch.
Spelljammer 3E Conversion Project - Spelljammer Wiki - The Spelljammer Image Group.
Moderator of the Spelljammer forum (and administrator). My moderator voice is green.

User avatar
Big Mac
Giant Space Hamster
Posts: 25116
Joined: Sun Jun 15, 2008 3:52 pm
Gender: male
Location: London UK
Contact:

Re: Seeing Planets From a Distance

Post by Big Mac » Wed Sep 11, 2019 12:26 pm

Jaid wrote:
Wed Sep 11, 2019 6:09 am
should probably account for brightness/reflectiveness to some extent. a giant disco ball in a sphere with a very strong fire body nearby might be visible from much further away than usual. and of course, a fire body itself will be more visible than normal.
The real-world term for this is albedo, which comes from a Latin term for "whiteness".

I would suggest that we might want to convert real-world albedo over to Man in the Funny Hat's system somehow.

So, perhaps a fire body, like Sirrion, could be bumped up to a larger sized planet, for the purpose of deciding how far away you can see it.

White planets (ones covered in snow) could also be bumped up in size.

Black planets (that absorb a lot of sunlight) or voidworlds (that don't have an atmosphere to reflect or refract light) might count as smaller-sized celestial bodies (for visibility purposes).

If we went with something like that, we could have a table to go with Man in the Funny Hat's original table that includes +1 for this and that. and -1 for this and that.

Wikipedia has the astronomical albedo for all the real-world planets in the Solar System, if anyone fancies playing around with albedo to see how real-world numbers affect magnitude, but I think it would be a total nightmare to try to simulate that accurately. I would suggest doing that only to get a rough idea how much of a plus or minus albedo should give you.
David "Big Mac" Shepheard
Please join The Piazza's Facebook group, The Piazza's Facebook page and follow The Piazza's Twitter feed so that you can stay in touch.
Spelljammer 3E Conversion Project - Spelljammer Wiki - The Spelljammer Image Group.
Moderator of the Spelljammer forum (and administrator). My moderator voice is green.

User avatar
Big Mac
Giant Space Hamster
Posts: 25116
Joined: Sun Jun 15, 2008 3:52 pm
Gender: male
Location: London UK
Contact:

Re: Seeing Planets From a Distance

Post by Big Mac » Wed Sep 11, 2019 12:52 pm

AuldDragon wrote:
Wed Sep 11, 2019 6:29 am
I generally ignore real-world optics for Spelljammer, for the primary reason that entering a sphere and seeing the (big) planets laid out in dazzling display is so much more interesting and evocative than telling players they basically can't see anything except for a few dots and blackness.

It has the added benefit of making space combat with mile distances and accuracy more reasonable. It is the opposite of the passenger side mirror message: "Objects in Spelljammer appear closer than they are."
I do like that, from some respects.

But there is a reason why PCs buy spyglasses.

And navigators have to do something.

I think it might be better to have a dazzling display of new stars and have the navigator and the lookouts spend a few moments searching for expected constellations, to take bearings from.

The rest of the spacehands (and the PCs) could also be asked to look around the part of the sky towards the centre of the crystal sphere to see if they can spot any "moving stars" (i.e. planets).

I think that rolling some spot checks for PCs (and NPCs) and having the PCs actually spot a moving star and calling out it's colour and position, could give you a narrative that has all the excitement you are talking about and more.

Instead of the PCs seeing the outer bodies of Realmspace laid out in front of them, people could call out a few constellations (which confirms the ship has indeed arrived in Realmspace) and then the crew/PCs could be searching for Coliar (Size G), Chandos (Size F), Toril and Glyth (Size E) and Karpri (Size D) along the ecliptic.

Working out the constellations that go around the ecliptic (which Argentmantle has been kind enough to put on the three maps he made for Greyspace, Krynnspace and Realmspace) would make it easier for the crew to switch focus to the line of the sky that passes through them and the Sun.

So each success could allow for additional checks to be made until enough planets have been spotted to reveal the planetary system.

If you take that sort of approach, H'Catha could be fun. It's Size C with two moons, so should be fairly visible. But because it is a flatworld, it's albedo should drop to next to nothing, when it is side on. It could be good storytelling to make this world change shape as the PCs ship flies through the crystal sphere.
David "Big Mac" Shepheard
Please join The Piazza's Facebook group, The Piazza's Facebook page and follow The Piazza's Twitter feed so that you can stay in touch.
Spelljammer 3E Conversion Project - Spelljammer Wiki - The Spelljammer Image Group.
Moderator of the Spelljammer forum (and administrator). My moderator voice is green.

User avatar
Big Mac
Giant Space Hamster
Posts: 25116
Joined: Sun Jun 15, 2008 3:52 pm
Gender: male
Location: London UK
Contact:

Re: Seeing Planets From a Distance

Post by Big Mac » Wed Sep 11, 2019 12:57 pm

Jaid wrote:
Wed Sep 11, 2019 7:44 am
fun fact: there is a wizard spell that focuses air into a lens to allow you to see further. it would be pretty funny if air envelopes naturally formed such a lens :P
That would work well for the way AuldDragon wants to do things.

Alternatively, why not turn the large eye-shaped windows that appear on the sides of most spelljamming ships into lenses and have the navigator stand inside that room to get a good view of the crystal sphere around the ship.

That would give the eyes of the ship a proper function, rather than have them be something that looks quirky for no reason.

You might also want to consider doing something with helmsight. A helmsight spell that is related to your "air lens" spell could allow a helmsman to have long-range vision all around the ship.
David "Big Mac" Shepheard
Please join The Piazza's Facebook group, The Piazza's Facebook page and follow The Piazza's Twitter feed so that you can stay in touch.
Spelljammer 3E Conversion Project - Spelljammer Wiki - The Spelljammer Image Group.
Moderator of the Spelljammer forum (and administrator). My moderator voice is green.

User avatar
Man in the Funny Hat
Hobgoblin
Posts: 74
Joined: Fri Jan 22, 2010 4:03 pm
Gender: male
Location: The Inland Empire
Contact:

Re: Seeing Planets From a Distance

Post by Man in the Funny Hat » Wed Sep 11, 2019 4:31 pm

Well, I thought initially about factoring in reflectivity/albedo but that gets into a large can of worms. Fire bodies are not all the same size, brightness, temperature, color, etc. There is not always a fire body at the center of a system. There are often multiple fire bodies around a system, especially if it's being randomly generated. It just brings in too many fudge factors. The work to actually quantify and categorize and enable cross-referencing all that is FAR more than it could possibly be worth. This is, after all, Spelljammer and not hard sci-fi or even Traveler. A simple table of planet size vs. distance I thought should be good enough. You might want to NOTE that there could be a lot of other factors but the degree to which you want to incorporate them and whether you want to just fudge it or have even more detailed charts and tables depends on whether because you consider a particular factor more significant or because you just want more crunchyness for the sake of crunchyness.

For myself I just figured I'd look at a planet and say to myself, "It's a dark color, it's far from a fire body or anything else, and it's a bit small therefore it should require being closer." In fact, I suggest that might be how best to handle it. Each factor that should make it harder to see from a distance shifts it one category worse. Maybe two if you think it warrants it. Too dark - 1 shift worse. Fire body - at least 1 shift easier, but more likely 2, possibly 3 depending on brightness. Too far from a fire body or other major light source - 1 shift worse. Planet is between you and the light source - 1 shift worse. You are between planet and light source - 1 shift easier. That would be easy to manage.

User avatar
Big Mac
Giant Space Hamster
Posts: 25116
Joined: Sun Jun 15, 2008 3:52 pm
Gender: male
Location: London UK
Contact:

Re: Seeing Planets From a Distance

Post by Big Mac » Wed Sep 11, 2019 4:46 pm

Man in the Funny Hat wrote:
Wed Sep 11, 2019 4:31 pm
Well, I thought initially about factoring in reflectivity/albedo but that gets into a large can of worms. Fire bodies are not all the same size, brightness, temperature, color, etc. There is not always a fire body at the center of a system. There are often multiple fire bodies around a system, especially if it's being randomly generated. It just brings in too many fudge factors. The work to actually quantify and categorize and enable cross-referencing all that is FAR more than it could possibly be worth. This is, after all, Spelljammer and not hard sci-fi or even Traveler. A simple table of planet size vs. distance I thought should be good enough. You might want to NOTE that there could be a lot of other factors but the degree to which you want to incorporate them and whether you want to just fudge it or have even more detailed charts and tables depends on whether because you consider a particular factor more significant or because you just want more crunchyness for the sake of crunchyness.

For myself I just figured I'd look at a planet and say to myself, "It's a dark color, it's far from a fire body or anything else, and it's a bit small therefore it should require being closer." In fact, I suggest that might be how best to handle it. Each factor that should make it harder to see from a distance shifts it one category worse. Maybe two if you think it warrants it. Too dark - 1 shift worse. Fire body - at least 1 shift easier, but more likely 2, possibly 3 depending on brightness. Too far from a fire body or other major light source - 1 shift worse. Planet is between you and the light source - 1 shift worse. You are between planet and light source - 1 shift easier. That would be easy to manage.
I totally love how you say that my suggestion would open a can of worms...

...and then immediately solve the problem! :cool:

If I had a hat (funny or not) I would take it off to you.
David "Big Mac" Shepheard
Please join The Piazza's Facebook group, The Piazza's Facebook page and follow The Piazza's Twitter feed so that you can stay in touch.
Spelljammer 3E Conversion Project - Spelljammer Wiki - The Spelljammer Image Group.
Moderator of the Spelljammer forum (and administrator). My moderator voice is green.

Post Reply

Return to “Spelljammer”