I investigated MoO 1, and measured its parsecs in pixels (if you turn the grid, lines are spaced 5 parsecs apart. DOSBox upscales the screen from 320x240 to 640x480). I found that 5 parsecs equals 100 pixels, so 1 parsec = 20 pixels. I then measured the star sprite, it's 11 pixels. I then compared my star's sprite, which is 32. Almost exactly 3 times bigger, so I've set my game's 1 parsec to be equal to 60 pixels.
Then I implemented fuel ranges, mostly. There's some bugs and some polishing-up that I need to do before it's complete. While implementing this, I thought, it's kinda annoying having to click on a star with your scout, and see if it's within range. If not, click on another star, and so forth.
So I decided to add a visual layout of your fuel range. This can be toggled on/off by pressing the "F" key (I will later add radar range layout when I get to radar code). You can see two circles in the below screenshot, the normal range and range with extended fuel tanks. On left, the destination is within range, while on right, due to colony ship having no extended fuel range, the destination is out of range. What do you think? Something that you'd use?