Here are this week’s best astronomical events that you can view right from your backyard. Below is a picture of the Flaming Star Nebula, featured on APOD this week. Although the star AE Aurigae apperas to be on fire, it is in fact just surrounded by smokey interstellar hydrogen and carbon-rich dust grains. More information here if you are interested! Happy exploring!
For small creatures such as we the vastness is bearable only through love. –Carl Sagan
You can use the star chart provided here. And for any terms or units you may be unfamiliar with, I’ve provided a glossary at the end of the guide for your convenience. All events were calculated based on Boulder, CO (latitude 40⁰ N), but should provide good approximations for most cities near the same latitude. If you would like, you can change your location on the linked sites for each event. Let me know if you have any questions. I’d love to know what you see this week!
Thursday 12/3
00:19 MST Moon at Last Quarter
The Moon will be at last quarter tonight, becoming visible around 00:19 MST when it rises 7⁰ above the Eastern horizon. The Moon will reach its highest point 56⁰ above the Southern horizon around 05:58 MST. The different Moon phases occur because of our changing perspective as the Moon orbits the Earth. The phases cycle every 29.5 days–from new moon, to first quarter, to full moon, to last quarter, and then finally to new moon again. The half phase is ideal for observing the craters and mountains on the Moon’s surface. More information here.
Friday 12/4
01:08 MST Moon-Jupiter Conjunction
The Moon and Jupiter will be very close, passing within 1⁰42’ of each other. The Moon will have a magnitude of -11.6, while Jupiter will have a magnitude of -2.0. Both will be located in the constellation Leo. From Boulder, the pair will be visible at dawn, rising at 01:08 MST and setting at 06:48 MST around sun rise. They will attain an elevation of 54⁰ above the Southern horizon. More information here.
17:57 MST ISS Passing
The ISS will make a visible pass (magnitude -2.6) starting at 10⁰ elevation in the SSW and moving ESE, reaching a highest elevation of 36⁰. More information here.
17:48 MST Iridium Flare (Iridium 59)
The Iridium 59 satellite will cause an iridium flare of magnitude -4.5 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 31⁰ in the South. More information here.
Saturday 12/5
15:00 MST Moon at Apogee
The Moon will reach the furthest point in its orbit from Earth. The Moon’s distance from the Earth varies because its orbit is not perfectly circular. Instead, the Moon traces out an ellipse with Earth at one of its foci. The Moon’s distance varies by 10% throughout its orbit (between 363,000 km and 405,000 km), which means its size in the night sky varies by nearly 13%. Because the apogee occurs near a new moon, the moon will appear as a small crescent in the sky, with an angular size of 29.50′, as compared to its average angular size of 31.07′. It should also be noted that the Moon’s apparent size in the sky will also vary depending on its vicinity to the horizon. For instance, the Moon will appear much larger when it is closer to the horizon. More information here.
Sunday 12/6
02:07 MST Moon-Mars Conjunction
The Moon and Mars will be very close, passing within 0⁰05’ of each other. The Moon will have a magnitude of -11.1, while Mars will have a magnitude of 1.1. Both will be located in the constellation Virgo. From Boulder, the pair will be visible at dawn, rising at 02:07 MST and setting at 06:49 MST around sun rise. They will attain an elevation of 43⁰ above the SE horizon. More information here.
17:48 MST ISS Passing
The ISS will make a visible pass (magnitude -3.4) starting at 10⁰ elevation in the SW and moving NE, reaching a highest elevation of 87⁰. More information here.
Monday 12/7
03:34 MST Moon-Venus Conjunction
The Moon and Venus will be very close, passing within 0⁰38’ of each other. The Moon will have a magnitude of -10.4, while Venus will have a magnitude of -4.7. Both will be located in the constellation Virgo. From Boulder, the pair will be visible at dawn, rising at 03:34 MST and setting at 06:49 MST around sun rise. They will attain an elevation of 30⁰ above the SE horizon. More information here.
17:45 MST C/2014 S2 at Brightest
Comet C/2014 S2 will reach its brightest (magnitude 9.1) tonight. It will lie at a distance of 2.10 AU from the Sun and 1.92 AU from the Earth. From Boulder it will be visible all night because it is circumpolar. It will become visible near dusk around 17:45 MST, 35⁰ above the NW horizon. It will be highest in the sky just before dawn until twilight at 05:59, 36⁰ above the NE horizon. More information here.
Tuesday 12/8
17:39 MST ISS Passing
The ISS will make a visible pass (magnitude -2.3) starting at 10⁰ elevation in the WSW and moving NNE, reaching a highest elevation of 38⁰. More information here.
Wednesday 12/9
24:00 MST Puppid-Velid Meteor Shower
The Puppid-Velid meteor shower will reach its peak activity tonight. Shooting stars associated with the shower should be visible from November 17th through January. The maximum rate of visible meteors is expected to reach 15 per hour; however, this zenithal hourly rate is dependent on many factors, such as sky conditions, light pollution at the observer’s location, and altitude of the meteor shower’s radiant in the sky. The Moon will be 28 days old at the peak, and so will present minimal interference. At midnight, the shower’s radiant will appear 28⁰ below the SE horizon from Boulder, with the meteors traveling directly outward from this point. In order to see the most meteors possible, it is best to look at any dark patch of sky 90⁰ around the radiant, rather than at the radiant itself. This is because the meteors will typically appear brightest at these locations. It is so named the Puppid meteor shower because of its radiant’s location with the constellation Puppis. More information here.
17:45 MST C/2014 S2 at Perihelion
Comet C/2014 S2 will make its closet approach to the Sun tonight, at a distance of 2.10 AU. From Boulder, it will be visible all night because it is circumpolar. It will become visible near dusk around 17:45 MST, 34⁰ above the NW horizon. It will be highest in the sky just before dawn until twilight at 06:01, 37⁰ above the NE horizon. More information here.
Glossary
Apogee: The point in the orbit farthest away from the Earth.
Apehelion: The point in the orbit farthest away from the Sun.
Arcminute: An angular measurement, defined as 1/60 of one degree. Denoted by ‘. (approx. 1 inch at a distance of 100 yards, the Moon is approx 31’)
Arcsecond: An angular measurement, defined as 1/60 of an arcminute. Denoted by “. (approx. dime at a distance of 1 mile )
A great resource for understanding and approximating angular measurements in the night sky, here. The Moon is approx 1/2⁰. Your outstretched hand is approx 20⁰, with each finger approx 1⁰. Your closed outstretched palm is approx 10⁰.
AU: Astronomical Unit, Defined as the distance between the Sun and Earth.
Conjunction: An alignment of two celestial bodies such that they present the least angular separation as viewed from Earth.
Elongation: The angle between the Sun and a planet, with Earth as the reference point. The greatest elongation of a planet occurs when this separation angle is at its largest. More information here.
Iridium Flare: Iridium fares occur when sunlight is reflected off the antenna (of one of the 66 active telecommunication sats in LEO, known as the Iridium constellation) directly down at Earth. This reflection causes an illuminated spot on the surface of the Earth. To an observer on the ground, the event appears to be a bright flash, or flare in the sky, which lasts for a few seconds.
ISS: International Space Station. More information here.
Magnitude: A logarithmic measure of the brightness of an object. Brighter objects have a lower (more negative) magnitude. More information here.
Opposition: When a celestial body is opposite the Sun in the sky.
Perigee: The point in the orbit closet to the Earth.
Perihelion: The point in the orbit closest to the Sun.
Radiant: The point in the sky where meteors of a meteor shower appear to originate.
Time Conversions from MST
Eastern Daylight Time, EST = MST + 2:00
Central Daylight Time, CST = MST + 1:00
Mountain Daylight Time, MST
Pacific Daylight Time, PST = MST – 1:00
Alaska Daylight Time, AKST = MST – 2:00
The standard for astronomical times is UTC if you happen to come across it, where MST = UTC – 6:00.
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