Moon Occults Regulus
Weekly Featured Sight for February 1-7
Another week is dawning, which means that it’s time to highlight another especially noteworthy event taking place in the night sky. This week’s feature may require rearranging one’s sleep schedule for people lucky enough to see the event in all its glory, but it will be worth it. Why? The Moon is going to occult (block) Regulus for some of us on Monday night/Tuesday morning.
So, how to go about seeing this event?
First of all, the big question is whether you will be able to see the occultation at all or merely a close pass of the two heavenly bodies. The saying that location is everything doesn’t apply just to real estate, but this week’s feature as your geographical location on Earth will determine what you can see. To see what the sky will offer where you live, go here, plug in your geographical coordinates, and find out!
If you are able to see the occultation itself, keep reading. If not, content yourself with a close pass of the two bodies and skip the next few paragraphs to this week’s Other Items of Note section.
If you can see the occultation, you’re in for a treat. If you have ever been lucky enough to see a total solar eclipse and a transit of Venus, you are familiar with what will be described below.
Venus has a very thick, dense atmosphere. In a transit of Venus, the last of which took place in 2012 and the next won’t take place until 2117, when the planet moves across the face of the Sun, it will always appear fuzzy. No amount of tweaking the focus on the telescope will change this for one simple reason: the fuzzy look is the direct result of the thick atmosphere that traps heat and makes Venus, at over 900 Fahrenheit, the hottest planet in the solar system.
In contrast, the Moon has essentially no atmosphere whatsoever. For anyone who has ever seen a total solar eclipse, the result is dramatic as the Sun appears to turn off and then back on again like a light bulb. Any solar eclipse watcher knows that timing is of the essence, especially if watching the event through a telescope. A total solar eclipse can only be safely viewed without eye protection during totality. The instant the Sun reemerges from behind the Moon, it is as if a light switch has been flipped (as my above video of the 2017 eclipse shows) and the eye protection must go back on immediately or permanent damage to one’s vision may result. Why the sudden change? The Moon has no atmosphere to slow the transition. If the Moon had a thick atmosphere like Venus, there would be a few seconds of time where the Sun visibly dimmed and then brightened again, not the instantaneous on/off phenomenon.
What we will see with the occultation of Regulus is essentially a solar eclipse, but with Regulus substituted for the Sun. This will be another case of ‘now you see it, now you don’t,’ but at least with Regulus no eye protection will be required!
Oh yes, if you’re freezing your fingers off while observing the occultation of Regulus, here’s a warm thought: Regulus is alpha Leo, a prominent spring constellation.
Other Items of Note
While not a specific thing to this week, February will offer the last real chances for most of us to observe Saturn under truly dark sky conditions. While Saturn can be observed as soon as it pops out of the evening twilight, if you have a telescope, the dark sky that arrives around 90 minutes after sunset is required to see the planet, and especially its moons, in all possible detail. Speaking of a dark sky, at the start of the month, sunset is starting to come noticeably later. Even people who couldn’t care less about astronomy will find the lengthening of the day impossible not to notice.
Other day non-specific events should be noted as being things to look for in early February. First, Deneb of the Summer Triangle is still sticking around after sunset, provided you have a good Northwest horizon. Jupiter, which reached opposition last month, will be just about due South at nightfall as February begins. Gemini, the constellation of the month for December thanks to its namesake meteor shower, is now very well placed in the Eastern sky just after nightfall.
Tuesday the 3rd is sure to be a happy for a lot of people as this day marks the mid point of winter 2025-26. There’s no doubt that the winter sky has a lot to offer but, on the other hand, the season also brings a lot to dislike. Who reading this likes clouds obscuring the sky and then trying not to freeze solid on those frustratingly few nights when it is clear? Not many, I’m sure.
On Saturday, the Moon meets Spica, alpha Virgo, in the predawn sky. To see the pairing, no telescope is required as the eye is plenty sufficient to do the job. Simply go out in the predawn hours and look South to spot the waning gibbeous Moon parked right next to blue Spica, alpha Virgo. Oh yes, this is a great time to acquaint yourself with spring’s stellar road map. Look North to spot the Big Dipper, then follow the arc of the handle to bright orange Arcturus, the brightest star of the spring sky and alpha Bootes. From Arcturus, continue the line and speed onto Spica. From Spica, if you’re observing under a still dark sky, continue the curve to Corvus the crow, a trapezoid of 2nd magnitude stars low in the South/Southwest.
Today is a double feature, so why not check out the other half?