Here are this week’s best astronomical events that you can view right from your backyard. Events this week include the chance to observe asteroid 192 Nausikka and several exceptionally bright iridium flares. I’d love to know what you discover in the night sky! Below is a beautiful picture of the Pelican Nebula, featured on APOD this week. And here are even more pictures of the Pelican Nebula to love, if you’re interested. Happy exploring!
The sky is the ultimate art gallery just above us. –Ralph Waldo Emerson
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 11/19
17:01 MST Moon at First Quarter
The Moon will be at first quarter tonight. 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.
17:15 MST Iridium Flare (Iridium 46)
The Iridium 46 satellite will cause an iridium flare of magnitude -7.0 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 32⁰ in the SSW. More information here.
Friday 11/20
02:21 MST Mars at Aphelion
Mars will be at its farthest point from the Sun at a distance of 1.67 AU. While this doesn’t affect Mars’s appearance, it will be be visible from Boulder in the dawn sky. It will rise at 02:21 MST, attain an altitude of 38⁰ above the SE horizon, and fade from view with dawn around 06:07 MST. Because Mars has a significantly elliptical orbit, its distance from the Sun varies by 20%, between 1.38 AU and 1.67 AU. More information here.
17:09 MST Iridium Flare (Iridium 49)
The Iridium 49 satellite will cause an iridium flare of magnitude -3.1 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 31⁰ in the SSW. More information here.
17:57 MST Asteroid 192 Nausikaa at Opposition
Asteroid 192 Nausikka will be well placed for observation in the constellation Perseus and will lie well above the horizon for much of the night. Regardless of your location on Earth, 192 Nausikaa will reach its highest point at midnight local time. From Boulder it will be visible between 17:57 MST and 05:08 MST. It will rise 24⁰ above the NE horizon before reaching its highest point in the sky, 82⁰ above the southern horizon. More information here.
18:45 MST Iridium Flare (Iridium 58)
The Iridium 58 satellite will cause an iridium flare of magnitude -7.5 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 32⁰ in the SSE. . More information here.
Saturday 11/21
06:18 MST ISS Passing
The ISS will make a visible pass (magnitude -3.3) starting at 10⁰ elevation in the NW and moving ESE, reaching a highest elevation of 75⁰. More information here.
18:39 MST Iridium Flare (Iridium 55)
The Iridium 55 satellite will cause an iridium flare of magnitude -4.3 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 32⁰ in the SSE. More information here.
Sunday 11/22
16:57 MST Moon-Uranus Conjunction
The Moon and Uranus will be very close, passing within 0⁰53’ of each other. The Moon will have a magnitude of -12.6, while Uranus will have a magnitude of 5.8. Both will be located in the constellation Pisces. From Boulder, the pair will become visible around 16:57 MST as the dusk sky fades, 26⁰ above the eastern horizon. The pair will reach its highest point 55⁰ above the southern horizon around 20:56 MST, and will remain visible until 02:38 MST when they sink below the western horizon. More information here.
Monday 11/23
06:08 MST ISS Passing
The ISS will make a visible pass (magnitude -2.8) starting at 13⁰ elevation in the WNW and moving SSE, reaching a highest elevation of 43⁰. More information here.
15:35 MST Moon at Perigee
The Moon will reach the closest point in its orbit to the Earth. This close approach occurs when the Moon is near full phase, and so the Moon will appear unusually large and bright (called a supermoon). 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%. Tonight the Moon will appear to have an angular size of 33.32′, 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.
Tuesday 11/24
05:17 MST ISS Passing
The ISS will make a visible pass (magnitude -3.5) starting at 71⁰ elevation in the NW and moving SE, reaching a highest elevation of 88⁰. More information here.
16:18 MST Moon at Apehelion
The Moon will reach the furthest point in its orbit from the Sun, at a distance of 0.9965 AU. The Moon will lie on the opposite side of the Earth as the Sun. For comparison, the Earth will lie at a distance of 0.9944 AU from the Sun. More information here.
Wednesday 11/25
17:07 MST Full Moon
The Moon will reach full phase, lying almost directly opposite the Sun in the sky. Full moons are traditionally given names according to the season in which they occur. This will be the third full moon of autumn, and thus will be called the Beaver Moon. More information here.
18:24 MST Iridium Flare (Iridium 45)
The Iridium 45 satellite will cause an iridium flare of magnitude -7.3 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 33⁰ in the SSE. 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.
2 Comments
tinyurl.com
December 8, 2015 at 7:58 amAppreciate this post. Let me try it out.
Kristin
December 12, 2015 at 7:49 pmPlease do! And let me know what you see. I’d love to hear back from you!