[oAlbe]

Is there a way to rapport an arcmin to a measurement that would be more easily understandable? Not necessarily as a multiple of grains of rice.

[jcims]

Your thumb at arms length is ~2 degrees or ~120 arcminutes wide. The fingernail on your index finger at arm's length is ~1 degree or 60 arcminutes wide.

The moon is about half a degree or 30 arcminutes wide. This doesn't make sense but give it a try tonight if the moon is out.

FWIW many of the galaxies and nebula you see in astrophotography are actually bigger in the night sky than one might guess. Andromeda for example is about 6 times wider than the moon at ~3 degrees across - https://slate.com/technology/2014/01/moon-and-andromeda-rela...

[BurningFrog]

I propose we use Moon Diameters (MD) as the official HN unit for sky distance.

[sbierwagen]

A minute of arc is one sixtieth of a degree. (A "minute", get it?)

The moon is between 29.4 and 33.5 arcminutes wide, depending on where it is in its orbit. So about a tenth of the width of the moon.

[leeoniya]

> So about a tenth of the width of the moon.

this is so much more digestible than "grain of sand at arm's length", and those two metrics dont feel at all equivalent -- the moon is not ten grains of sand at arm's length wide, right?

[zola]

I always translate it in my mind to full moons. 30 arcmin == diameter of full moon as seen from earth.

[yvoschaap]

7.3 arcminutes = 16 light-years

[mwint]

Wait, but it’s a ~cone, right? So it must be 16ly across at some specific distance from us?

[agrajag]

That's the distance of an object away that has a parallax of 7.3 arcminutes and a baseline of 1AU. The 7.3 arcminutes referenced here is the width of the image on the celestial sphere.