Another angular size question.

[Gunnie]

Is there a good catalogue (online perhaps) of the angular sizes of different objects? For example, sizes of different nebulae. I understand that a lot of those glorious pictures in the magazines are of objects that are not actually too small to see, but too dim. Other things I'm curious about... angular sizes of distant galaxies, maximum separation between planets outside our solar system and their host stars, any thing really. Another question. I've heard the smallest angular size the human eye can resolve is something like one arc minute. Where can I find the angular sizes of the planets? Could the naked eye resolve the disk of say Jupiter were it not for the glare? I know I've tried.

[Carlos_dfc]

Angular sizes of the planets varies all the time.
Jupiter, which is just past opposition, is currently around 45 arcseconds across (maybe a little bigger, but not much) - it maxes out at about 50 arcsec at opposition.
Mars gets to a max of about 24 arcsec at opposition, but is currently more like 4 arcsec because it's currently across at the other side of the Sun from us.
Saturn gets to 20-odd arcsec too (much bigger than Mars, but also much further away), currently around 16 arcsec because it too is across at the other side of the Sun - Saturn's ring diameter is a little more than double the size of the globe.
Venus can vary between about 10 and 60 arcsec, depending where it is - It is biggest in angular size, when it's only a thin crescent.
Mercury, Uranus, Neptune are always very small.

To find different sizes of deep sky objects (nebulae, galaxies, star clusters etc) visit the NGC/IC project
[Registered users can see links. ]
It has searchable databases that give all sorts of info on the 13,000+ objects from the NGC and IC catalogues, including angular sizes of anything more than a couple of arcseconds aross