FRIDAY, FEBRUARY 11

■ This evening the waxing gibbous Moon shines close to the vertical midline of the Winter Hexagon: the line from brilliant Sirius in the southeast up to Capella high overhead.

To trace out the whole enormous Hexagon, start with Sirius at its bottom. Going clockwise from there, swing up through Procyon, then Pollux and Castor, then Menkalinan and Capella overhead, down to Aldebaran, then to Rigel in Orion's foot, and back to Sirius. Betelgeuse shines inside the Hexagon, far off center.

The "Hexagon" is somewhat distended. But it's fairly symmetic around that long vertical axis, Capella to Sirius.

All four terrestrial planets remain visible at dawn this week. The three in the sky form a slowly changing triangle, with Venus powerfully dominating.

SATURDAY, FEBRUARY 12

■ Now the Moon shines in Gemini. Look for Castor and Pollux lower left of it early after dark, as shown below.

This whole pattern rotates clockwise as it moves across the sky through the night. So Castor and Pollux shine directly left of the Moon later in the evening, then above the Moon in the early hours of Sunday morning.

The bright Moon crossing Gemini, Feb. 12-14, 2022
On Sunday the 13th, the Castor-Pollux line briefly spears the Moon during evening (for most of North America) as the Moon travels eastward.

SUNDAY, FEBRUARY 13

■ Now the Moon shines in a line with Castor and Pollux, as shown above. The lineup is precisely straight around 9 p.m. in the Eastern time zone, 8 p.m. Central, 7 p.m. Mountain as twilight is ending, and 6 p.m. Pacific where the sky may be too bright to see the stars.

How well can you judge the exact lineup time where you are? The actual time will be a little different across the continent regardless of time zone. This is because the Moon is moving eastward along its orbit, and because different vantage points on Earth have slightly different lines of sight to the Moon (topocentric parallax), and Earth is carrying you eastward as it rotates at a different projected speed with respect to your line of sight to the Moon as the Moon changes altitude in your sky.

Hold a straightedge to the Moon and stars, and you may be able to fix the lineup time to an uncertainty of 15 minutes or less. You'll do better if you press or clamp one end of the straightedge against something to hold it motionless. Measure many times, and take the midtime between when the center of the Moon last seems just a trace off the Castor-Pollux line, and when it first seems just a trace off on the other side.

Welcome to pre-telescopic astronomy and to techniques of scientific measurement generally. This kind of thing, done in vast quantities by skilled people using naked-eye tools outdoors at night, eventually enabled Kepler to derive and prove the laws of planetary motion, Copernicus and his successors to determine the correct model of the Sun-centered solar system, and Newton to use these to discover the universal laws of gravitation.

The Moon, as you may find, travels along its orbit by about one Moon-diameter per hour.

MONDAY, FEBRUARY 14

■ The Moon has traveled east into dim Cancer. It forms a long, gently curving arc with the two Dog Stars: Procyon in Canis Minor and then brighter Sirius in Canis Major. This star-arc extends to the Moon's right in twilight, and lower right of it later in the night. The three are spaced about 25° apart.

TUESDAY, FEBRUARY 15

■ Full Moon tonight and tomorrow night for the Americas. The Moon is exactly full at 11:56 a.m. Wednesday morning Eastern Standard Time, about halfway between this evening and tomorrow evening.

This evening the Moon shines just to the upper right of the Sickle of Leo. The Sickle's two brightest stars are Regulus, about 10° below the Moon, and Algieba (Gamma Leonis) the same distance to the Moon's lower left, as seen from mid-northern latitudes.

WEDNESDAY, FEBRUARY 16

■ Now the Moon, as full as it was yesterday evening, shines lower left of Regulus and Algieba, and closer to them: about 5° from each this time.

THURSDAY, FEBRUARY 17

■ It's mid-February, so Orion stands at his highest in the south by about 8 p.m. Here he looks smaller than you probably remember him appearing early in the winter when he was low. You're seeing the "Moon illusion" effect. Constellations, not just the Moon, look bigger when they're low.

■ Under Orion's feet, and to the right of Sirius now, hides Lepus the Hare. Like Canis Major, this is a constellation with a connect-the-dots that really looks like what it's supposed to be. He's a crouching bunny, with his nose pointing lower right, his faint ears extending up toward Rigel (Orion's brighter foot), and his body bunched to the left. His brightest two stars, 3rd-magnitude Alpha and Beta Leporis, form the back and front of his neck, respectively.

FRIDAY, FEBRUARY 18

■ On these February evenings Canopus, the second-brightest star after Sirius, lurks either just below or maybe just above your south horizon. In one of the many interesting coincidences that devoted skywatchers know about, Canopus lies almost due south of Sirius, by 36°. That's far enough south that it never appears above your horizon unless you're below latitude 37° N (southern Virginia, southern Missouri, central California). And there you'll need an open, flat south horizon. Canopus crosses the south point on the horizon 21 minutes before Sirius does.

When to look? Canopus is due south right when Beta Canis Majoris — Murzim the Announcer, the star about three finger-widths to the right of Sirius — is at its highest due south over your landscape. That's about 8 or 9 p.m. now, depending on how far east or west you live in your time zone. Drop straight down from Murzim then.

Have you been watching the Venus-Mars-Mercury triangle at dawn? The angle at Mars was less than 90° a week ago, as shown at the top of this page. Now it's essentially a right angle (more exactly so than it appears above due to slight map distortion). How well can you judge this?

SATURDAY, FEBRUARY 19

■ Right after night becomes completely dark this week, the W of Cassiopeia shines high in the northwest, standing almost on end.

The brightest star between Cassiopeia and the zenith at that time (for the world's mid-northern latitudes) is Alpha Persei or Mirfak, magnitude 1.8. It lies on the lower-right edge of the Alpha Persei Cluster: a large, elongated, very loose swarm of fainter stars about the size of your thumbtip at arm's length. At least a dozen are 6th magnitude or brighter. They show best in binoculars.

Alpha Per, a white supergiant, is a true member of the group and its brightest light. It and the rest are about 560 light-years away.

 

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This Week's Planet Roundup

Mercury, Venus, and Mars continue to shine in early dawn, as shown above. They're low in the southeast, forming a triangle that changes shape slightly through the week.

Brightest is Venus, now peaking at a dazzling magnitude –4.9. In a telescope it's a thick crescent; the globe appears about a quarter sunlit, as it always does when Venus is at its greatest brilliancy.

Mars is only one three-hundredth that bright at a puny magnitude +1.4. Look for it 6° to Venus's lower right.

Mercury is more twice that far to Venus's lower left. It's about magnitude 0.0 all week.

Jupiter (magnitude –2.0, in Aquarius) sinks ever lower in evening twilight day by day, soon to depart. Look for it above your west-southwest horizon as twilight deepens. It sets before twilight ends.

Saturn is out of sight in the glare of the Sun.

Uranus (magnitude 5.8, in Aries) is high in the southwest after dark. Finder chart.

Neptune (magnitude 8.0, in Aquarius) is sinking away in the west-southwest, trailing behind Jupiter unseen.


All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Standard Time, EST, is Universal Time (also called UT, UTC, GMT, or Z time) minus 5 hours.


Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy.

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown here is the Jumbo Edition, which is in hard covers and enlarged for easier reading outdoors by red flashlight. Sample charts. More about the current editions.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. The next up, once you know your way around, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And be sure to read How to Use a Star Chart with a Telescope. (It applies just as much to charts onscreen as to charts on paper.)

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner.

Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically, meaning heavy and expensive. And as Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."


Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty's monthly
podcast tour of the heavens above. It's free.



"The dangers of not thinking clearly are much greater now than ever before. It's not that there's something new in our way of thinking, it's that credulous and confused thinking can be much more lethal in ways it was never before."
            — Carl Sagan, 1996

"Facts are stubborn things."
            — John Adams, 1770

 

Comments


Image of Rod

Rod

February 11, 2022 at 8:27 am

Yes, all four terrestrial planets are observable near sunrise. This morning near 0600 EST I could see Venus easily (behind a tree line), as well as some of Earth - I think I was standing on this planet 🙂 On 09-Feb I enjoyed some telescope time viewing the waxing gibbous Moon. The Moon was moving through Taurus, its apparent orbital motion quite obvious using reference stars to watch it moving along. I thought this was cool. Here is a note from my log. [Observed 1900-2030 EST/0000-0130 UT. First Quarter Moon 08-Feb-2022 1350 UT. Waxing gibbous Moon tonight in Taurus moving through Taurus. I used my 90-mm refractor telescope with TeleVue 32-mm plossl eyepiece for 31x views and true FOV ~ 96 arcminutes. The Virtual Moon Atlas reports the Moon’s angular size near 29.99 arcminutes. I viewed using Orion Moon filter and observed craters Plato, Archimedes, and Moretus in the south limb. Earthshine visible on night side of the Moon with limb observable, no Moon filter used when I observed this. During the 90-minute observation period, I watched the Moon move by two stars in Taurus, 51 Tau (mv + 5.6), and 56 Tau (mv +5.3). Near 2020 EST and shortly after, 56 Tau was about one arcminute angular separation from the Moon's southern limb according to Stellarium 0.21.3, not far off from Moretus crater area near the terminator line. I used Virtual Moon Atlas to confirm the lunar areas. Earlier in the evening near 1900 EST or a bit earlier, 56 Tau was slightly more than 21 arcminutes angular separation from the Moon according to Stellarium 0.21.3. This was enjoyable observing the Moon's orbital velocity carry it along and change position relative to these two stars in Taurus that I used as references tonight, tracking the Moon’s position changing in the night sky. I was able to observe fainter stars near the Moon tonight, I could see HDS 553 (Stellarium 0.21.3) apparent magnitude + 8.75. I moved the south limb of the Moon into the corner of the eyepiece to reduce brightness from the waxing gibbous Moon to see these fainter stars. Weather clear skies, temp 5C and winds south at 8 knots. Lovely time viewing this evening and watching the Moon move through Taurus constellation using references stars to check its progress and position changes. This was very obvious in the telescope view and cool too ]

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Anthony Barreiro

February 11, 2022 at 7:52 pm

Careful observation and reasonable approximation are still practiced in celestial navigation. By measuring the height of the Sun above the horizon with a sextant around true local noon you can easily calculate your latitude and longitude, if you have an accurate timepiece and an almanac with the Sun's declination north or south of the equator and distance west of the Greenwich meridian. The Sun's maximum height in the sky, plus or minus the Sun's declination, gives you your latitude. Timing the moment when the Sun is highest in the sky allows you to calculate your longitude. In practice you determine that moment by measuring the Sun's height a short while before noon and then noting when the Sun returns to that height after noon. The moment halfway between those times was your local apparent noon.

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mary beth

February 11, 2022 at 11:34 pm

Now to Miletos he steered his course
That was the teaching of old Thales
Who in bygone days gauged the stars
Of the Little Bear by which the Phoenicians
Steered across the seas

Just a tidbit from this excellent PBS NOVA webpage. Based on their “Lost at Sea: The Search for Longitude” episode. I bet most of you have seen this and/or read the book that it is based on.

https://www.pbs.org/wgbh/nova/longitude/secrets.html

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New Jersey Eclipse Fan

February 12, 2022 at 11:07 pm

Well, Mary Beth, I have neither seen nor read it. But I like (in the traditional sense of the word) the prose (or is that poetry?)!

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mary beth

February 13, 2022 at 12:52 am

Glad you like it! Kallimachos (Also spelled Callimachus) had a refined style of writing that became known as Callimacheanism. I think it would be considered poetry. He liked things short and sweet compared to his epic writing contemporaries! I guess had he been alive today he would’ve invented Twitter!

If you can find that NOVA episode on YouTube I highly recommend it. I haven’t seen it in years and I’ll probably try to watch it again tomorrow! It prompted me to read another good book called The Riddle of the Compass. Might re-read that as well!

Hope you and all of your family are doing well!

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cyrtonyx

February 16, 2022 at 12:57 pm

I once spent a night on Alcatraz....but that is another story........

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Anthony Barreiro

February 13, 2022 at 7:11 pm

Mary Beth, studying the history of astronomy led me to an interest in celestial navigation, and then to sailing and navigation more generally. Three years ago when I took a three-day celestial navigation course aboard the schooner Seaward sailing out of Sausalito to Drake's Bay and the Farallon Islands, most of the other students were experienced sailors who were fairly new to astronomy. I was fairly new to sailing but more familiar with the sky. We met in the middle.
If you're sailing on the open ocean, celestial navigation is a useful backup and check on GPS. In recent years the US Naval Academy has resumed teaching celestial navigation to cadets.

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mary beth

February 13, 2022 at 11:34 pm

Anthony, I had a feeling you sailed. That must’ve been a wonderful experience. I’m sure everyone was glad you were on board! i’m glad the Naval Academy is teaching the basics again. People are too dependent on automation. I always like to understand the basics of something then I feel more comfortable using equipment. I bet you got some great photographs during your course. Did you spend the night on the boat or did you come back each day?

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Anthony Barreiro

February 14, 2022 at 1:44 pm

The cruise was grand. We slept on the boat for three nights. I never got into the habit of taking photos, so I only have memories.

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Rod

February 13, 2022 at 11:42 am

Anthony, very good, some old school here 🙂 I have a Naval Academy book that shows much on navigation before satellites and GPS. 'Navigation and Nautical Astronomy' by Dutton, 1926-1951 US Naval Institute 1951. Preface by Commander Benj. Dutton, Annapolis MD, May 25, 1926. Some serious navigating by sea and the air 🙂

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Rod

February 13, 2022 at 11:44 am

Hope folks have been doing some winter stargazing and observing, I know mary beth has. I checked my log for 03-Jan-22 thru 11-Feb-22, 14 days out and 18 hours at the eyepiece 🙂 Today light snow in my area.

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mary beth

February 13, 2022 at 11:38 pm

Quite impressive! Is that a personal record for this early in the year? Yes, I’ve been enjoying the stars and the thought of what’s looming in the east for Spring! Canopus such a delight right out my south facing front door. The moon was bright snd beautiful tonight, it almost washed out Pollux!

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Rod

February 14, 2022 at 9:01 am

mary beth, no record here. In December 2021 I was out for 8 days and more than 8 hours. I keep my log in MS ACCESS DB, created tables, queries, forms, and reports as well as charts created using Stellarium and Starry Night 🙂

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New Jersey Eclipse Fan

February 14, 2022 at 12:53 pm

As always, great reading all the posts. It snowed all day Sunday here in Central Jersey, but it was so light that we only got about 4" total, still enough to beautify the surroundings. By bedtime, we already had clear skies, but I was too tired to trudge outside into the cold. There's always tonight! BTW my wife and I no longer celebrate it formally, but Happy Valentine's Day, everybody!

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Rod

February 15, 2022 at 11:22 am

Good to see New Jersey Eclipse Fan posting 🙂 I am happy to report that the last two evenings, I tested a number of older eyepieces with my 10-inch Newtonian reflector using the Moon as the target. I tested my TeleVue Nagler 9-mm eyepiece that is more than 30 years old now. Great views of the Moon and using moon filter too. The magnification was 133x with true FOV near 37 arcminutes or a bit more than 0.6-degree. At 133x, that provides a nice, wide view with good magnification.

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New Jersey Eclipse Fan

February 16, 2022 at 2:47 pm

Gee, thanks! I am most definitely not social-media savvy, though sometimes live vicariously through my wife's facebook account. In fact, the only other one I joined was my high school's alumni association platform, and that was five years ago in preparation for my 40th(!) reunion. I graduated Cheltenham H.S. in suburban Philadelphia in 1977. My aforementioned wife also graduated the same year, albeit in Baltimore. That means, according to the Mason-Dixon Line, I married a Southern Belle!

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