Monday, December 5, 2022


The upcoming Blood Moon – a rare treat!


Astronomy for RVers

By Chris Fellows, Serenity Mobile Observatory

Correction: The eclipse starts on January 20 around 10 p.m. on the East Coast and will run till the wee hours of the morning on the 21st. Thanks to our astute readers for catching this. Our apologies for the error.

North America will be treated to this fantastic sight only once in 2019/2020. On Monday, January 21, 2019, not long after sunset, all of North America will be treated to an event that shouldn’t be missed. A total lunar eclipse isn’t exactly a rare event but jot this down on your calendar or you’ll have to wait until 2021 for the next one.

Total Lunar Eclipse by Astrophotographer and fulltime RVer John Adler. Taken Sept 27, 2015. in Hot Springs, SD. John used a Canon EOS Rebel XS / 75 – 300 mm zoom lens / tripod. Thank you John!

Lunar eclipses come in two flavors like any eclipse or occultation: partial and total. In a partial eclipse the shadow or body of the occulting object only partially covers the occulted object. As you may have already surmised, in a total eclipse the shadow or body completely covers the occulted object normally, making for a much more dramatic event.

This eclipse will be visible from anywhere in the country that isn’t clouded over so your chances of seeing it are good. The eclipse’s penumbra, the defuse area of the moon’s shadow, will begin at around 9:30 p.m. on the East Coast and 6:30 p.m. on the West Coast. About an hour later the umbra or sharp area of the moon’s shadow will start taking bites out of the moon’s disk. A little over an hour after that we will be in totality and the blood moon will dominate the sky. Unlike a solar eclipse that lasts only minutes and is observable at only very specific locations, a lunar eclipse will last hours, with totality lasting just over an hour, and it will be visible anywhere on the night side of the planet.

There is a great website for looking up all kinds of interesting events called Time and that you can use to determine when the event will start and how long it will last in whatever part of the country you happen to be in.

Why the total eclipse of the moon is red (image from Wikipedia)

So, you may ask, why is the blood moon red? This is an interesting phenomenon and it is the same reason a sunset is red. When sunlight hits our nitrogen- and oxygen-rich atmosphere those molecules scatter blue light. This is the reason our sky is blue. The wavelengths in the part of the electromagnetic spectrum that we perceive as the color blue, 450um and shorter, can’t dive straight in but are reflected all over the place by the air we breathe.

The rest of the spectrum with its longer wavelength is less affected and comes through as yellow or white light that illuminates everything we see – except for the times near sunset or sunrise when the blue light scattering is much more severe due to the angle and thus the amount of atmosphere it is traversing to reach our eyes.  At those times (angles) almost all the blue light is being absorbed or bouncing off into space so everything is pushed into the red end of the spectrum.

Now imagine that those red photons never hit your eye but went right past your head and back off into space. They would travel in a straight line and anything they illuminated would appear red. That is what is happening during a blood moon. The light from the sun is mostly blocked by the earth, but a very small amount is passing through our atmosphere, losing almost all of its blue end of the spectrum in the process, and continuing on to hit the moon making appear red. Cool, eh?

Astrophotographer Nerida Langcake took this series of shots with a Samsung S8 smartphone through a 6″ reflector, in Melbourne, Australia, on Jan. 31, 2018.

I, for one, am looking forward to this eclipse as I should still be in the desert this mid-January and have an excellent chance of getting great views. A lunar eclipse is also a great excuse to get family and friends together, have a picnic dinner and sit outside and watch the mechanics of our solar system in action.

Let me know if you observe this eclipse and what your impressions are. I know they always make me smile.

Till next time!

Clear Skies,
Chris Fellows, Serenity Mobile Observatory

Find Chris on Facebook (or, if you’re lucky, at your campground). (Editor: Check out his amazing photos on his Facebook page!)


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Christopher Fellows
3 years ago

I went back and checked my original source and ran a simulation in my planetarium software. The eclipse starts on Jan 20th around 10 PM on the east coast. and will run till the wee hours of the morning on the 21st. I don’t know how I got this wrong when I wrote the article because the original source point has it correctly as the 20th. I apologize for the confusion and misinformation.

Al & Sharon
3 years ago

NOTE: The eclipse in the USA starts SUNDAY evening Jan 20, 2019. The Jan 21st date is because the “official” time is UTC time which is the time in England.
You really need to change your website info to reflect or clarify the times for the eclipse in the USA

Nerida Langcake
3 years ago

Great article Chris ??

Sherry Dawson
3 years ago

Check this site for the exact times of the different phases of the eclipse. I The times are shown for Atlanta, so it’s easy to extrapolate for your time zone. Scroll down below the eclipse map until you see the chart at:

Steve Sims
3 years ago

Chris — The actual time of the lunar eclipse is Jan 21, 2019 at 02:36:29 (UTC). So for east-coasters, that’s around 9:30pm on *Sunday* the 20th.
Please correct your article so as to avoid a lot of RV’ers being 24 hours late to the party!

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