If you live in North America, you will have a chance to see something really cool that you must be in the right place at the right time to see!
On the morning of February 18, if you are an observer in Mountain and Pacific Time Zones before dawn over North America, you will have a chance to see the Moon block Mars, and then watch Mars reappear on the other side of the Moon less than an hour later!
We call these events occultations.
So… What’s The Deal?
Occultations happen somewhat frequently, but their visibility over your location is what can make them rare treats. Remember that the Moon and planets all share the same plane along the ecliptic – the apparent path traced by the Sun in the sky visible over Earth. As their positions in the sky shift over time due to the Moon’s orbit around Earth, and all the planets’ orbits around the Sun, ever so often the Moon will appear to cover a planet.
It’s called an occultation because it’s basically a larger closer object in the foreground blocking (occulting) a smaller distant object in the background.
When it’s the opposite, a small foreground object passing in front of a larger object and not completely obscuring it, we call it a transit. We only use the term “eclipse” when the blocking object in question is casting a shadow onto the observer.
When Does This Event Happen?
This will be the only occultation visible over North America for 2020.
The actual occultation will begin at around 11:30 UTC, which will translate to 6:30 am eastern/ 3:30 am pacific. But understand the actual minute times will vary by location, so it is important that you consult with other websites dedicated to these events, particularly this one. The reason why the times vary has to do with your perspective angle… and how long Mars stays behind the Moon. Much like needing to be within the central path of the moon’s shadow to see the full solar eclipse, if you’re too far north or too far south, you won’t see Mars disappear behind the Moon, and you’ll instead see a still impressive looking close conjunction.
When the event starts, you will see the waning crescent Moon closely approach Mars, which will appear as a bright red/orange “star” to the naked eye and as a tiny disc through a telescope. Then you will see Mars appear to “set” behind the crescent, and then reappear on the other side of the Moon about an hour later.
Why this happens is from Earth’s perspective, the Moon’s 27-28 day orbit makes it appear to shift eastward half a degree (or about the same width of a full moon) every hour! Meanwhile, Mars eastward shift is much slower along the ecliptic due to its 687 day orbit around the Sun, covering half a degree approximately every 18 hours or so.
Okay That Sounds Cool… How Do I See It?
This event favors most of North America and the Continental U.S. It will not be visible from Alaska or Hawaii as it will happen when both objects are below the horizon.
The event will happen before sunrise over the western half, thus Pacific and Mountain time zones will have the best views, while the eastern half will see this event after sunrise and observers wishing to see it will still need a telescope with enough light gathering power to see the fainter Mars get blocked by the brighter Moon.
Mars’ reappearance from behind the Moon will be a spectacular naked eye event for those living in Mountain and Pacific Time zones, as it will still be night time, and because of a phenomenon we call earthshine, the Moon’s night side will be faintly visible, even more so through telescopes!
As long as you have good weather, this will be a celestial event you don’t want to miss!
Click On this Link from occultations.org to see a list of times of major cities when the Moon disappears and reappears. Remember that the times listed are in UTC, so whatever that time is listed, subtract the hour by 5 if Eastern, 6 if Central, 7 if Mountain, and 8 if Pacific time respectively.
Note: Places in the Pacific Northwest like San Francisco, Portland, Seattle, and Vancouver are in an odd spot where the Mars disappearance happens before moonrise, but observers there will still be able to see the spectacular reappearance. Thankfully, down in Southern California where yours truly is observing from, I’ll be able to see both parts… If I find the right location.
Note For Southern California Observers: If you’re observing from Southern California, to see Mars initially disappear at you will need to find a spot that has almost NO obstruction of the southeastern sky, which is not easy if there are mountain ranges to the east in the Greater LA area. The moon rises around 3:13 am, and the disappearance will occur around 3:37 am.
The big moment of Mars reemerging that is definitely worth waking up for will be around 4:29 am! The Moon will be higher, and much easier to spot by then!
So I’m an Aries and Mars is My Ruling Planet…
I’m the wrong guy to ask to about that…
Live Stream Info
The event will be be broadcast live on Facebook Live on The Facebook Page Associated with This Website. I will find a spot with as little obstruction as I can from Southern California and hopefully catch the initial disappearance. If I cannot catch the disappearance, you are most assured that I will definitely broadcast the reappearance an hour later!
If you happen to be awake, be sure to tune in around 3:25 am at the earliest. If you just want to check out the ending, start coming in at around 4:15 am and give yourself enough time to relax and watch the show! During the waiting period, you can always drop in, and we can have a chat!
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