Back in Classical Greece there was some debate as to what the cause of a lunar eclipse was. By this time it was generally accepted that it was due to the Earth coming between the Moon and the Sun and casting a shadow. But one point of evidence that was presented against this theory was that on occasion lunar eclipses were observed at sunset. You could clearly see both the Sun and the Moon, so the Earth did not appear to be between the two. This issue with the idea that lunar eclipses are due to the Earth's shadow wasn't really satisfactorily addressed until the 1700s or so when the refraction of light was systematically studied (though by the Hellenistic Era no one seriously doubted it).<p>This actually wasn't the only time when the refraction of the Earth's atmosphere produced surprising observations in the ancient world. One of the devices the Greeks used to determine the time of an equinox was what is called an equatorial ring. It's basically just a metal hoop oriented at an angle equal to 90 degrees minus the latitude. (Here's a diagram: <a href="https://en.wikipedia.org/wiki/Equatorial_ring#/media/File:Equatorial_ring.png" rel="nofollow">https://en.wikipedia.org/wiki/Equatorial_ring#/media/File:Eq...</a>) During an equinox the Sun would be right on the celestial equator, and the shadow cast by the upper half of the hoop would fall exactly on the bottom half.<p>But it was noticed that sometimes, the shadow would fall on the bottom half early in the morning, then cross to the other side, cross <i>back</i>, and then later cross over once again --- it seemed that there was three equinoxes! Ptolemy explained this away as being due to instabilities in the device's orientation --- somehow it was very slightly tilting and so it wasn't possible to measure the time of the equinox to better than half a day or so. But today we know that this was also due to the refraction of the atmosphere. Early in the morning, the Sun would be refracted to appear to be just above the celestial equator, but as it rose, the refraction would lessen and it would fall back to its original place. Then later in the day it would cross the celestial equator "for real" when the equinox actually occurred. So the device was much more accurate than ancient astronomers gave it credit for!
Wikipedia has a picture from 2014: <a href="https://en.wikipedia.org/wiki/File:Lunar_eclipse_at_sunrise_Minneapolis_October_2014.png" rel="nofollow">https://en.wikipedia.org/wiki/File:Lunar_eclipse_at_sunrise_...</a><p>Here's a nice post thinking through how you might actually observe this: <a href="https://photoephemeris.com/articles/the-selenelion-challenge" rel="nofollow">https://photoephemeris.com/articles/the-selenelion-challenge</a>
Sunset is kind of a fluid thing. The lunar eclipse on May 15 last year happened right around sunset as viewed in the SF bay area. A little way further south or west would have been an even brighter sky for the eclipse. <a href="https://photos.app.goo.gl/pjbefmFcv2THZEQ19" rel="nofollow">https://photos.app.goo.gl/pjbefmFcv2THZEQ19</a> are a few photos I took of this. The red of the eclipse was initially almost invisible due to how much light there still was in the sky, and it only became clearer as the ambient light diminished.
Yes, a selenelion will happen just before sunset or just after sunrise when the sun and moon are at opposite points of the horizon. This is also called a horizontal eclipse and is due to the atmosphere not the planet. [1] [2]<p>[1] <a href="https://sciencenotes.org/selenelion-eclipse/" rel="nofollow">https://sciencenotes.org/selenelion-eclipse/</a><p>[2] <a href="https://www.space.com/27338-total-lunar-eclipse-rare-sunrise-selenelion.html" rel="nofollow">https://www.space.com/27338-total-lunar-eclipse-rare-sunrise...</a>
It is possible (atmospheric effects as stated by others/the article), but not in a useful sense of having something that looks impressively like a lunar eclipse.<p>In other trivia, expect that a solar eclipse will also happen somewhere on Earth in any month that has a lunar eclipse. (exactly because of similar alignment issues)
A lunar eclipse can happen at any time of the day, might only be visible on the other side of the planet - maybe the question he meant to ask was "can you see ...."
Yes always possible. If you consider the light spectrum is split during sun set and rise. So you will get more red light spectrum, during set/rise. You will see more green during night ie Nothern lights. And obviously mostly blue during the day.
Betteridge says no, but the headline says yes.<p><a href="https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines" rel="nofollow">https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headline...</a><p>Perhaps there should be an exception for Stackoverflow.