Month: October 2020

Looking to the north when the sky is dark, we may be in for a little light show on the night of October 6^th. Much like Draco Malfoy casting a verdimillious charm, shooting green sparks from the tip of his wand, the constellation Draco may dazzle us with a greater than average number of shooting stars coming from its radiant. (OK, so this reference is a bit of a stretch but I couldn’t resist…)

The Draconids are one of the less spectacular annual meteor showers, yielding only 2 to 3 meteors per hour on average. However, according to Jérémie Vaubaillon of the Institute for Celestial Mechanics and Computation of Ephemerides, this year may be different.  Since we will be passing close to not just one but two different debris trails left behind by comet 21P/Giacobini-Zinner, the number of meteors we might see per hour goes from 2 up to 10. Admittedly, 10 per hour is not all that fantastic either; we’ve moved from underwhelming to whelming.

This shower is unusual in that it’s best viewed early in the evening rather than after midnight, like most of the annual meteor showers. This is great news, because the 83% illuminated waning gibbous Moon, which will make the fairly faint Draconid meteors hard to see, rises around 9:45 PM MDT. We’ll have about two hours of dark skies to do our observing. For more information on meteor showers in general, check our previous blog post.

While you’re waiting for Draco’s verdimillious magic, why not test your visual acuity and sensitivity with these challenges straight from Professor Sinistra’s astronomy class:

Separate Mizar/Alcor
The middle star at the bend in the Big Dipper’s handle is actually two stars, a naked eye binary separated by 11.8 minutes of arc. This pair is not only the first double star discovered (1617), but the first to be photographed with a telescope (1857). Those with keen vision should be able to separate objects 7 or 8 degrees apart, so separating Mizar and Alcor should be an easy task.

Find the Double Cluster
The double cluster is two groups of white supergiant stars believed to be formed from the same cloud of gas and dust. Each of these open star clusters contains 300 – 400 stars that are loosely gravitationally bound. In fairly dark skies this is a naked-eye object, you would see it as a fuzzy patch; if you’re observing from a location with light polluted skies, you will need a pair of binoculars to see these clusters. The double cluster can be found between the constellations Cassiopeia and Perseus; use the sky chart below to locate it.

Find the Andromeda Galaxy
The Andromeda galaxy is a huge spiral galaxy much like our own Milky Way. At 2.5 million light years away, this is the most distant object you can see with your naked eye. Again, you will need to be in a fairly dark sky location to see this object without the aid of binoculars. Use the sky chart below to help locate this object, which will appear as a faint fuzzy patch.

So tomorrow night drag out your lawn chairs and a blanket or two, and spend a couple of hours searching for meteors, testing your vision, and enjoying the beauty of the night sky.

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

Did you happen to catch the full Moon rising last night? It was a beauty! If you missed it, try again tonight, as it will rise during nautical twilight and appear to be nearly full. The Moon rose before astronomical twilight and was nearly full the night before last night’s Harvest Moon as well. Why does this happen?

Normally the Moon rises about 50 minutes later each day. But near the autumnal equinox when the ecliptic (an imaginary line in the sky that marks the annual path of the Sun) and horizon form a narrow angle, the Moon rises only 25-30 minutes later each day for several days in a row. In addition, on the days before and after the full Moon, it’s only about 1° or 2° less illuminated, as illustrated in the LunaSolCal print screens below.

If you observe the nearly-full Moon tonight you’ll be in for an extra treat – Mars will be nestled close by, only about 1.5° away. You can measure the approximate distance between the Moon and Mars using your pinky, as shown in the sky chart below. If you extend your arm out fully in front of you, your pinky will cover about 1° of the sky. Therefore, the Moon and Mars will be about a pinky-and-a-half apart. For a reminder of how to measure distances in the sky using your hands, check out this previous blog post.

If you’re up before sunrise, look to the east to find the planet Venus, which rises at about 4 AM. Venus will be easy to pick out because at a magnitude of -4 it is brighter than any other planet or star you can see in the sky. (Check out the end of this previous blog post for a brief explanation of stellar magnitude.) This morning I did a little experiment to see how close to sunrise I could still see Venus in the ever-brightening sky. Venus was easy to pick out at 6:30 AM, as was the 1.6 magnitude star Regulus in the constellation Leo a half-degree below it. If you look tomorrow morning, Venus will appear about a half-degree below Regulus, and will continue to move away from the star at the rate of about a degree per day.

Venus was still just barely visible at 6:50 AM toward the end of civil twilight, 15 minutes before sunrise. In reality, it probably would have been pretty hard for me to pick Venus out of the bright sky had I not started watching it when it was easy to find.

While you’re out looking for Venus in the pre-dawn sky, look for the constellation Orion as well. It will be easily visible into the beginning of civil twilight, appearing high in the sky to the south.

Eyes to the Skies!

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

by Jon Spargo

MARS ATTACKS!
All Sci-Fi references aside, the red planet will be a scant 38,547,383 miles from Earth on October 6th. In recent times, it has been closer to Earth only in 2003 and 2018. You can celebrate “Opposition” from the Sun on the 13^th, when Mars will be 38,959,973 miles from Earth. What makes this year’s appearance special is that Mars will be well north of its sky position in 2018. During this month, its peak magnitude will be -2.6, briefly outshining Jupiter. It will be ideally placed for viewing surface features. So, break out your telescopes and go for it! Mars will not be this close to us again until 2035.

Jupiter and Saturn will continue to dominate the early evening sky. The magnitudes of both planets fade slightly by the end of the month. Both are still well placed for telescopic observations of moons and rings. Both planets reach eastern quadrature late this month which means they cast shadows to the east. This will enhance viewing of eclipses of Jupiter’s moons and shadows from Saturn’s rings.

Early-morning sky watchers will be rewarded as brilliant Venus still rises at least 3 hours before the Sun. Shining at magnitude -4.1, its visible phase increases from 72 to 81 percent of its cloudy atmosphere. Tiny Mercury will not be visible to us this month.

The Moon will be full on the 1^st, last quarter on the 10^th, new on the 16^th, first quarter on the 23^rd, and full again on the 31^st. So, for Halloween, we’ll have a “Blue Moon” which is two full Moons in one month. It also happens that the full Moon on the 1^st will be the “Harvest Moon.” The Harvest Moon is the full Moon nearest to the equinox which was September 22^nd.

Looking east on the mornings of October 13 and 14, about an hour before sunrise, the waning crescent Moon will visit brilliant Venus.

Looking south-southwest on the night of the 22^nd, the nearly first quarter Moon can be found just below and about halfway between Jupiter and Saturn.

Looking east on the 29^th, one hour after sunset, the nearly full Moon will be just below the red planet Mars.

Stay safe and Clear Skies!