The Celestial Event Scale – Revised

We are happy that the skies often have an incentive for you to go outside and look up.

It’s important to know which  events are worth making efforts for, and which events you don’t need to lose sleep over… literally.

Here is How I Rank the Celestial Events

This is a general idea on which events are so frustratingly over-hyped, which events don’t get enough attention, and which events actually deserve all the attention from dedicated and casual observers alike!

Let’s go over each category, what I list, and why:

“Oh, it’s a <insert monthly full moon name> Super Moon!” Yeah? So…? “Oh, but it’s occurring on a <given holiday> and they say that doesn’t happen very often!” Besides people obsessing over full moons, I’ve watched crowds of people applaud a sunset after it disappeared below the horizon.

Sure, there are definitely people who appreciate the poetic sense of some events we dedicated observers are so accustomed to, especially when it comes to the normal cycles of the Sun, Moon, planets, and stars… but sunrises/sunsets and full moons are like AC/DC albums – once you’ve seen one you’ve seen them all! It means no difference whatsoever if they happen to be occurring on a given holiday, or are the first and last for a particular month or year!

Super Moons When the Moon is at perigee. Even if it’s a tad closer, you won’t notice any difference to the naked eye!
Blue Moons They are the second full moon in a month… No, they won’t appear blue!
Black Moons The second new moon in a month – you WON’T SEE IT AT ALL!”
<Insert Name> MoonEvery full moon has a name, and you could easily find this out yourself!
The dates when Earth is closest to/furthest from the Sun during the year…
no, you won’t notice any naked eye differences in appearance nor changes
in usual seasonal temperatures.

These are events that many seasoned observers acknowledge, but don’t stress too much if they miss it. Most of the time, we end up having to correct the misconceptions due to many sources over hyping the event, making the event seem like it’s more impressive than it actually is. 

Oppositions Every year, Earth has a close approach opposition with those respective planets. It’s merely a time when it’s best to check them out. 
Weak to Average
Meteor Showers
Meteor showers that see one meteor every few minutes IF there is no moon and you’re away from cities. You might end up seeing more meteors during “non-shower” nights! But they’re still an excuse to go stargaze!
Conjunctions with ~ 2° SeparationTwo degrees is also equal to about four “full moons” in the sky. Objects this close together are visible through binoculars or a telescope at low magnification (<25x) at the same time.
Lunar Eclipses
From the Latin “paene” which means “almost.” Where the Moon crosses through Earth’s outer shadow (penumbra), but doesn’t quite touch the inner shadow (umbra) that causes the limb darkening. To the naked eye, you may not even notice they’re happening! 
Meteor Showers w/
Moon Interference
Reliably strong Meteor Showers that are plagued by interference from a prominent Moon will make the trip to the dark locations NOT WORTH IT!
They’re notable because they mark when times of the year are happening, or beginning/ending. Civilizations past and present planned festivals around these events.
Crescent Moon and Venus – 7/15/2018

Compared to “Notable,” “Impressive” Events are those more worth making the effort to see, whether it’s in the middle of the night, at a dark location away from cities, or both! 

On nights where there are more than two objects appearing close to each other to the naked eye, they can catch the eyes of the casual who otherwise isn’t looking up that often, and cause them to call up an astronomer and ask what they’re seeing.
Strong Meteor
Meteor showers with ZHR’s of 60-150 per hour or more, such as reliable Perseids and Geminids that have NO MOON INTERFERENCE!  These are worth the trip out to a dark location.  Dedicated and Casual Observers hate it when these events are blocked by clouds!
With ~1° Separation
Separated by “two full moons” means a telescope at medium power can pick up the two objects at the same time!
Close Approaches
When the distance between Earth and the respective planet is smaller than usual. Especially when it comes to Mars, there is a huge difference in how Mars appears from 40 million miles away versus its average of 140 million. 
Naked Eye SunspotsSunspots are fun to observe when they happen, but when a really large sunspot that’s larger than the size of Jupiter makes an appearance, they are worth putting the old eclipse glasses back on!
Asteroid or
Comet Flyby
When you have small objects like Near Earth Asteroids or certain comets pass us by only a few million miles, it’s a big deal. When these objects are bright enough for a telescope to spot, they’re fun to observe their motion!
Telescope Level CometA Comet that’s a great target to see through binoculars or a telescope… if you went to a dark enough location. Sure, you may glimpse them from a light polluted sky using your scope, but they contrast better and make better images from dark skies!

These are events that happen at least every few years, but may or may not be visible from your location – thus making them rare to see. Some of these rare events can end up “downgraded” on the scale due to lack of sense, desire, or inability to travel to dark locations, thus not witnessing at its best.

Lunar Eclipse 2019
Total Lunar
They happen every year or two, and as long as you’re on the night side of Earth when it happens, then you can see it! These are good events to plan parties around no matter where you are – as long as you can see it! But if it doesn’t work out, chances are another one of these is around the corner!
Partial Solar
If you’re on the day side of Earth and within the moon’s outer shadow, then you can see a partial eclipse. Sometimes this will be the best you can get given the circumstances of the path of the moon’s shadow. Other times, people who have a good chance to see the eclipse in full remain outside the inner path, and settle with a partial.
Outburst Meteor
Whenever Earth passes through a more dense cloud of debris, you can get double or even triple your usual rate of meteor showers. Potentially seeing hundreds per hour during peak times is well worth the trip to far away locations!
w/ ½° Sep.
When two planets are about “one full moon” apart or less, that means you can enjoy seeing both of them at the same time at medium to high magnification!
Naked Eye Level
These are comets that are without a doubt bright enough to see with the naked eye, even from moderately light polluted skies if you know where to look. With that said, even as far back as the early 20th century, people often miss out on, or get disappointed by these comets because of light pollution, and never see them at their best.
NEOWISE was definitely obvious over Joshua Tree National Park… but not quite over the cities.

Not only are events like these super rare, but you may never have the chance to check one out again! These are the events worth planning days/nights off work and taking your kids out of school for – hey, it’s for something educational!

These are the events that inspire people to get into astronomy, or inspire the poetic and artistic interpretations long associated with it!

Great American Eclipse 2017
Total Solar
There’s a reason why people travel from all over the world to see these sights, and why “Eclipse Chasing” is a thing! But you MUST be in the path of totality to witness it, otherwise you’re stuck with just a partial, and you’ve thus “downgraded!”
Annular Solar
While not as impressive as total, it’s still cool to travel and see the Sun and Moon align into a “ring of fire.” The same principle of getting within the central path still applies here!
Great CometsThey are defined as being so bright that they are noticed by casual observers who aren’t looking for them. Some comets are not yet considered “Great” while their shows are in progress, and it is only after they’re gone when they’re designated as such. So if you hear about a bright naked eye level comet, there’s always a chance you’re witnessing a “Great!”
w/ ¼° Sep
It’s super rare for planets to appear within 15 arc-minutes, or ¼° (half of a full moon diameter) apart, so when they happen, you better be outside checking it out, and if you don’t have a telescope, then you better get in touch with someone who does!
Moon Occults
A Planet
When these events happen, you can watch our Moon eclipse a planet, and then see that same planet reappear on the other side. You must be in the right place at the right time to see it! 
Meteor StormsWhen the ZHR rate reaches over a thousand per hour. These events are super rare, don’t last very long,  and are unpredictable. There are two showers associated with storms, the Leonids and Draconids, and if one wants to see them, you need to keep a close watch on when a storm is predicted – otherwise the two respective showers are rather weak.  
Transits of Mercury
or Venus
There’s usually 13-14 Mercury Transits per century (one every seven years on average), but you have to be on the day side of Earth when it happens, and you need a telescope with a solar filter to safely view. You could go decades without seeing one. Transits of Venus are MUCH MORE RARE, two transits separated by 8 years over a century apart, with the last one being in 2012. 

Would There Be Celestial Events We Would Consider “Off The Scale” or “Above the Scale” In A Sense of Wonder?


There would definitely be celestial events that we can observe, or have observed that we can safely say “that just doesn’t happen!” when compared to the events I listed and categorized prior. These are events that are so rare that we can forget they happen, or are mere “one in a million/ blink and you’ll miss it” chance occasions!

Naked Eye
Level Supernova
Supernovae have been observed in distant galaxies millions of light years away, but those that happen within our own galaxy are very rare and can outshine every star in the galaxy, and even be visible during the day! Last one like this to happen was 1604, which we call “Kepler’s Supernova.” We’re all looking at you, Betelgeuse!
Intensely Bright FireballMore of a “Blink and you’ll miss it” moment. But when they happen, and are spotted, the flashes and sounds they can create are quite stunning! Some of them are visible during the day, and others leave bright trails visible for a few minutes at night. We call these fireballs “Bolides.”
A Comet
Impacting another Planet
It’s a big deal if we can observe a large comet impacting another planet. When Shoemaker-Levy 9 was seen to do just that from telescopes on Earth in 1994, the sights of fireballs and dark “scars” on Jupiter shook everyone’s expectations, including seasoned astronomers!
It’s rare enough to witness one of these events, but an eclipse and transit, or two planetary transits across the face of the Sun at the same time?! It’s exceedingly rare, but it can happen. Mercury will be seen to transit during a partial eclipse in the year 6757 AD, Venus will transit during a total eclipse in 15232 AD, and both planets will transit across the Sun simultaneously in 69163 AD.
Planet Eclipsing Another PlanetIt can happen, but it’s also really rare. The next time a “Mutual Planetary Occultation” will happen will be in 2065, but it’ll be really difficult to see because the two planets involved (Venus eclipsing Jupiter) will be in close proximity to the Sun. These are also events that one must be in the right location observing at the right time to see, almost another “blink and you’ll miss” moment!

Of course, anything originating from the heavens that poses a threat to us would fall into the “off the scale” category, but that’s a discussion for another time!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s