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Following the moon

By Vernon Whetstone
Amateur Astronomer

With new moon tomorrow, this will be a great opportunity to follow it throughout an entire monthly cycle. We can start after sunset now, but by the end of the 28-day cycle we will need to be looking in the morning.
This new moon is the second one for January. Usually we hear about two full moons in one month with the second one being called a “Blue Moon.” However, up until recently I had not heard a name for a second new moon.
Perhaps it has not been named because it is not possible to see a new moon. The event occurs when the moon passes between Earth and the Sun, thus rendering it invisible. The only way to see a new moon is during a solar eclipse when it passes in front of the Sun blocking out its light.
I recently read of some group trying to call it a “Black Moon,” supposedly because you can’t see it. They also said because it was black we would be able to see it all day, but that statement has no basis whatsoever in fact.
As we follow the moon throughout the month we will watch as it passes several planets, some you can see, and two that will need optical aid.
For example, on Friday, Jan. 31, between 30 to 45-minutes after local sunset it could be possible to see a super-slender crescent moon near two planets, Neptune and Mercury. I say “possible” because both will be very close to the Sun and could be washed out in the glare of sunset, however, I think it would be worth a try.
For this, binoculars will be essential, so will an open and clear, uncluttered western horizon. Never, ever, look at or near the Sun with binoculars. It will be the last thing you ever see.
If you can spot the tiny, bright dot of the planet Mercury, put it at about the five o’clock position in the binocular field of view, the outer gas giant planet Neptune will be located at about the 11 o’clock position. The lunar crescent will be right and slightly below Mercury.
Keep watching Neptune and Mercury as they get closer together each night reaching their closest Feb. 4-5 on low horizon. The darker the sky the better.
By Feb. 3, the growing crescent of the moon has moved on to be near another outer gas giant planet, Uranus.
Viewing will be much easier because the pair can be viewed up to three hours after sunset. They will be very close and will be in the same field of view with the tiny dot for the planet below the moon.
I was once asked: Why does the moon keep passing several stars and the planets each month? Seems like it is always passing or is close to Jupiter and Saturn and Regulus in Leo, and Antares in Scorpius.
Answer: The planets and the moon all follow or are located along the ecliptic. The ecliptic is the path of the Sun through the sky against the background of the stars. Another way to explain it is the ecliptic is the plane of the galaxy, the path that all the planets follow in their orbits around the Sun.
The moon orbits Earth, but follows the ecliptic plane, so therefore, it will pass all those objects repeatedly. In fact, there are some occasions where the moon will pass directly in front of a planet or a star, that event is called an occultation.
SKYWATCH: New moon, Thursday, Jan. 30.
NEXT WEEK: More lunar and planetary meetings, and more astronomical blathering.