[Hyper Ion]

Nope, this is not what you think it is. What you are thinking right now is that I have no idea how to resize a nebula. Ha! Well, I know how to resize a nebula, but I think it's the game engine that is having trouble figuring it out.

I had this issue last year, but didn't feel like bringing it up until now. In-game, the nebulae I have placed in FRED become sized down for reasons unknown to me. Behold comparison screenshots.

In Game
In FRED

If you can't quite see it clearly, here's a closeup. The Aeoulus on the edge well help as a reference.

Close Up In Game
Close Up FRED

I spent hours getting the shot of the Sathanas vs. Aeolus just right due to this nebula size issue. I resorted to going into Notepad, doubling the sizes of each nebula, and then going back into FRED to reposition them so they weren't a clustered mess. Even then, the shot wasn't done to my original intention. It's obvious to me now that FRED and FreeSpace itself use two different kinds of perspective. However, I'm curious; is there a more reliable method of preserving intended nebula sizes? Or to a different question: does anyone even know this issue exists?

Sidebar: The intention of this screenshot was for an English class project of all things. We had to make a "poster" with an attached/relevant quote by Thoreau, mine being "However mean you life is, meet it and live it...". Apparently, the class thinks the Sathanas is a dragon....

[Shade]

Are you using a custom field of view setting by chance?

[Hyper Ion]

Nope. I wasn't using any custom flags back then, let alone the FOV one. And I still don't use the FOV flag.

[FUBAR-BDHR]

I've noticed this quite a few times as well.  All background objects in game seem smaller than in FRED not just the nebulae.  Put a planet in that takes up the whole screen in FRED and it's not even close in game. 

[Phoenova]

Maybe Fred renders backgrounds in a lower resolution than in game?