Show HN: Meteor shower, planet alignment, eclipse kit

jjmtrevarton about 4 hours ago 14 commentsRead Article on lifesprites.com

ZH version is available. Content is displayed in original English for accuracy.

I made this little walkthrough for finding the visible planets tonight and a meteor shower shooting start counter. Plus a little model of the solar system to try to wrap my head around what's going on. It's all based on your location if you provide it.

lifesprites.com/solar.html doesn't require account creation. The rest does. It's free, but you need an account.

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Discussion (14 Comments)Read Original on HackerNews

jmtrevarton•about 3 hours ago

I'm seeing that there's traffic coming from Europe. Realizing I use US measurements for everything. I'm working on fixing that right now. Sorry for the oversight.

jmtrevarton•about 4 hours ago

I still don't understand why there's a new moon when the moon is between the earth and the sun and a full moon when the earth is between the moon and the sun. Maybe if I stare at the model longer it'll magically make sense.

phn•about 3 hours ago

On the new moon, when the moon is between the earth and the sun, the light reflects back towards the sun, so you don't see it i.e. the moon is dark.

As for the full moon, the earth and sun are on the same side of the moon, so the sun is lighting the moon "from behind you" and you can see that.

jmtrevarton•about 1 hour ago

I keep thinking there should always be a little bit of a solar eclipse when there's a new moon. I think my model might need a z axis. Or maybe something in my mental model just still isn't right.

srean•about 1 hour ago

That's right.

In these missed eclipse the moon is usually a little too high or a little too down. The moon revolves on a plane that is tilted respect the Earth's plane of revolution. These two planes of revolution intersect at the the two points called nodes.

See this picture

https://en.wikipedia.org/wiki/File:Eclipse_vs_new_or_full_mo...

If the new moon happens to fall on the node then you will get a solar Eclipse.

nDRDY•about 2 hours ago

It might make more sense if you consider that the three objects are not usually aligned, due to the tilt of the moon's orbit around the earth. In the case of the full moon, this allows us to see the fully illuminated moon even when we are between it and the sun.

jmtrevarton•about 1 hour ago

Yeah that is the part that makes it confusing. Thank you!

simbas•about 3 hours ago

The new moon is in the sky when it's daytime. Crescents show at dawn/dusk. Full moon is night only.

jmtrevarton•about 3 hours ago

hence the eclipse today

jmtrevarton•about 2 hours ago

I think the measurements are fixed. Let me know if I'm wrong.

nephihaha•about 2 hours ago

Several hundred years ago, these combined would have been considered a major omen.

jmtrevarton•about 1 hour ago

According to X, they still are. I think they just make for a fun day though.