which given your location tells you what to expect. For me the news is bleak: full eclipse begins at 05:23 local time, and sunrise is just 4 minutes later, so the darkening of the moon's face probably won't register against the rapidly brightening sky. But the site overall is a go-to for easily digested information on all things daylight.
How amazing is timeanddate.com? I freaking love this site so much. Somehow it always seems surprising to me, maybe because of the colors or slightly cartoony look or something, I can’t quite put my finger on it. But the content is so consistently top notch, clearly made by people who care.
I actually very briefly looked into how get this basic data about sunrise/sunset/moonrise/moonset times and headings for any location on Earth (because I wanted to make a simple website to visualize the data as a fun side project). There must be some free/open source software models of the Sun-Earth-Moon system that could be combined with some basic GIS model of Earth to provide reasonably accurate data for any location on Earth, but I'm just so far away from these fields I probably don't know the right things to search for.
It basically depends on how accurate you want to be. I looked into this so I could generate lunar calendars for friends. I got the phases of the moon predictions from the BSD Games program pom by Keith E. Brandt[0], which is itself based on 'Practical Astronomy with Your Calculator'[1] by Peter Duffett-Smith. Lunar eclipse predictions came from the Basic Lunar Eclipse and Phase Calculator by Xavier Jubier[2]. These work well for the near future and with a reasonable amount of precision for regular people. You can get much more accurate using Astronomy Engine[3], but that was already a lot more complex than I wanted to get into
I'd agree about accuracy but it is also worth mentioning the time reach. Plus or minus half a century from now (or J2000.0 epoch) is fine but if you wanted to explore historical eclipses then you will need to look at higher precision series. This whole thing is about truncating trigonometric series with amplitudes and angles that change over time.
For sunrise/set and moonrise/set calculations you also need to allow for refraction in the Earth's atmosphere (around half a degree or so). Also for moonrise/set you need to allow for the parallax of the Moon's position because you are standing on the surface of the Earth not the centre (up to 1 degree difference in position). This all assumes a spherical Earth and an Ocean horizon. And the rise/set time can changes a little bit with your altitude above the horizon.
For latitudes near the Arctic/Antarctic circles any method based on iteration (as in Duffett-Smith's lovely book) is going to have convergence issues because there might not actually be a rise/set event near that day so if you really want an algorithm that will work anywhere on Earth you'll need to use a method based on fitting a quadratic curve to (say) 24 positions calculated for the day. Have a look at [1] in a library. The code is in Pascal, but it is the search method using a quadratic fit to sets of 3 consecutive positions you want.
Just for low-precision lunar positions, an interesting alternative that also summarises the various methods was produced by NASA [2] for space craft use.
Last time I looked into this I implemented some stuff from Astronomical Algorithms https://www.amazon.com/dp/0943396352 which was more fun for me than just grabbing the data.
It's one of my favorite sites. I love the focus on high quality, easy to interpret information without click bait, intrusive ads, etc. I wish there were more sites like it.
Ironically, the website is called "timeanddate" and I'm still confused by the times on this site. Perhaps I'm reading it wrong... let me know. Right now it's 12:53 PST, and the countdown says it's about 5hr 38 mins to go until the eclipse begins, but then if you click the Seattle link on that page [1] it says it actually begins at 8:34 pm PST. On top of that, it shows the maximum at 9:11 pm PST.
In short, maybe the countdown is 3 hours off? And it's trying to communicate the time left until the maximum?
- "8:34 pm: Moonrise / Rising, but the combination of a very low moon and the total eclipse phase will make the moon so dim that it will be extremely difficult to view until moon gets higher in the sky or the total phase ends."
People should give up on specifying the S or D in casual timezone references. Simply writing "12:53 Pacific" usually gets the point across. Incorrect usage of S during D times of year is far more common than the rare case where the indicator matters.
I just say "2 pm AZ" or "2pm utc-7", depending on who I'm talking to. MST is as likely to confuse someone ("oh, mountain time", then they're an hour off half the year) than it is to get it right.
That is something we should strive to correct people on. I've missed online events with friends because they would tell me "X pm PST", so I obviously just put the time in any time conversion app and end up being an hour late. It's easy for Americans, because you do your conversation by hand, for you people it means e.g. "one hour behind my time", but for everyone else who has to use an app to convert times, it's quite annoying and error prone.
Though it might soon be moot given USA is moving to permanent DST, so rather than people using PST wrong some of the time, it will be all of the time.
Out of sheer cussedness I just took a look (45 mins before start of total eclipse). The earth's shadow is quite apparent at this point but the sky behind it is already quite pale. So I great that once the "bite" is complete the contrast to a normal full moon will be obscured.
A lot of years ago, I watched a total eclipse of the moon from the parking lot of my husband's place of employment. My husband, our kids and some of his coworkers attended as well.
The moon turned red at some point. It was a pretty eerie experience.
If you can do so at least once in your life, I recommend it.
Total eclipses aren't all that common. Eclipses occur every six months, usually in pairs (one solar, one lunar, two weeks apart), but most are partial eclipses.
As good a time as any to remind everyone there'll be a total solar eclipse traversing the US in 2024[0]. If you haven't had the chance to see one before, this is likely your best shot until 2045
Oh so that's why we're having thunderstorms the next couple days :(
I've done a bit of searching and can find nothing that corroborates your statement. If you could link me to a study or other data source showing a correlation between lunar eclipses and specific weather events, I would be interested.
This explains a lot. I was driving in LA on vacation with my family and we were surprised to see the full moon covered by a “dark cloud” that kept covering more and more until I couldn’t see it for a while. The evening sky just made it seem like it must be cloud or smog in the distance.
Wish I could have gotten a picture. I've seen a few lunar eclipses before, usually looks like a round shadow slowly covering a flat disk. Something was different last night; Moon looked more 3-dimensional, at first like a round egg, then as the penumbra shadow fell, it started to look distinctly like an eye-ball. The rest was typical, but that part stunned me.
I got up to take a look, but after three days of entirely cloudless skies it was pissing down with rain and the cloud base somewhere around the top of the garden fence.
Of course even down south here at 56.5°N it still gets light really early this time of year, so it was already light enough to see that I was not going to see the moon.
I'm in Dublin. I can't remember the last time there was any sort of eclipse, meteor shower or alignment of the planets that wasn't obscured by cloud. If it had been yesterday morning it would have been clear.
Such quips aren’t well received on HN (for good reason unfortunately, look at Reddit), so let me instead entirely seriously state that I was not able to read that title without having that Bonnie Tyler song stuck in me head. That happened multiple times today.
which given your location tells you what to expect. For me the news is bleak: full eclipse begins at 05:23 local time, and sunrise is just 4 minutes later, so the darkening of the moon's face probably won't register against the rapidly brightening sky. But the site overall is a go-to for easily digested information on all things daylight.