Star Gazer’s Guide {Oct 29-Nov 4}

Here are this week’s best astronomical events that you can view right from your backyard. This week looks to be a bit less exciting than normal, but don’t let that deter you! There are plenty of bright satellites and iridium flares soaring across the night sky. Let your imagination run free! Every bright star you see has its own story. Who knows…one might just host another planetary system with life, like our own. Happy exploring!

Imagination will often carry us to worlds that never where. But without it we would go nowhere. — Carl Sagan

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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 10/29

All Night         Satellite Passings

There are quite a few brighter satellite passings tonight. More information here.

 

Friday 10/30

19:39 MDT         Iridium Flare (Iridium 11)

The Iridium 11 satellite will cause an iridium flare of magnitude -1.5 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 42⁰ in the SSE. More information here.

 

Saturday 10/31

17:57 MDT         Iridium Flare (Iridium 21)

The Iridium 21 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 36⁰ in the SSW. More information here.

 

Sunday 11/1

18:27 MDT         Iridium Flare (Iridium 76)

The Iridium 76 satellite will cause an iridium flare of magnitude 0.9 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 39⁰ in the SSE.  More information here.

 

Monday 11/2

05:01 MDT         Iridium Flare (Iridium 67)

The Iridium 67 satellite will cause an iridium flare of magnitude -4.1 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 39⁰ in the North.  More information here.

 

Tuesday 11/3

02:35 MDT         Venus-Mars Conjunction

Venus and Mars will be very close, passing within 0⁰40’ of each other. Venus will have a magnitude of -5.0, while Mars will have a magnitude of 1.4. Both will be located in the constellation Virgo. From Boulder, the pair will be visible at dawn, rising at 02:35 MDT and setting at 06:11 MDT around sun rise. They will attain an elevation of 38⁰ above the SE horizon. More information here.

04:55 MDT         Iridium Flare (Iridium 72)

The Iridium 72 satellite will cause an iridium flare of magnitude -4.0 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 37⁰ in the North.  More information here.

23:50 MDT         Moon at Last Quarter

The Moon will be at last 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.

 

Wednesday 11/4

18:18 MDT         Iridium Flare (Iridium 94)

The Iridium 94 satellite will cause an iridium flare of magnitude -1.9 that will be seen as a bright flash across the sky. The flare will begin at an elevation of 41⁰ 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 MDT

Eastern Daylight Time, EDT = MDT + 2:00

Central Daylight Time, CDT = MDT + 1:00

Mountain Daylight Time, MDT

Pacific Daylight Time, PDT = MDT – 1:00

Alaska Daylight Time, AKDT = MDT – 2:00

The standard for astronomical times is UTC if you happen to come across it, where MDT = UTC – 6:00.

 

Sources used here, here, and here.