Nova Cassiopeiae 2021 was still hovering around magnitude 7.6 as of October 29th, after nearly a dozen rises and dips since it first exploded from mag 15 to 7.7 last March. Charts and comparison stars.


■ Jupiter and Saturn continue to steepen their tilt in the southern evening sky this week, as shown below. Meanwhile, they are gradually creeping toward Venus which shines at nightfall far to their lower right.

The later you look, the steeper the Jupiter-Saturn line tilts. And, by late evening you'll find the binocular double stars Alpha and Beta Capricorni almost directly to Saturn's right, rather than upper right of it as in early evening.

■ Spot bright Capella sparkling low in the northeast these evenings. Then look for the Pleiades cluster off to Capella's right, by about three fists at arm's length. These harbingers of the cold months rise higher as evening grows late and watch for Aldebaran coming up below the Pleiades.

Upper right of Capella, and upper left of the Pleiades, the stars of Perseus lie astride the Milky Way.

■ A small telescope is all you need to watch Jupiter's big moon Ganymede slowly reappear from eclipse out of Jupiter's shadow around 8:31 p.m. EDT. It will come into view a little east of the planet.

Then Callisto emerges from eclipse, a little farther from Jupiter and even more gradually, 1¼ hours later: at about 9:47 p.m. EDT. (Convert the times to your own time zone.)


■ Spot bright Altair high in the southwest soon after dark. Brighter Vega is far to its right.

Above Altair lurk two distinctive little constellations: Delphinus the Dolphin, hardly more than a fist at arm's length to Altair's upper left, and smaller, fainter Sagitta the Arrow, slightly less far to Altair's upper right. Light pollution too bright? Use binoculars!


■ Halloween evening is moonless this year. But as twilight turns to night, bright Jupiter and lesser Saturn look down on trick-or-treaters from the south, and Venus blazes far to their lower right in the southwest.

The brightest star high in the evening is Vega, watching from very high in the west. And look two fists at arm's length lower left of Jupiter for Fomalhaut, the Autumn Star. Their eyes are upon you, and they say nothing.


■ Draw a line from Altair, the brightest star very high in the southwest after dark, to the right to Vega, very high in the west and even brighter. Continue the line onward by half that far, and you hit the Lozenge: the pointy-nosed head of Draco, the Dragon. Its brightest star is orange Eltanin, the tip of the Dragon's nose, always pointing toward Vega.

■ Just to Altair's upper right, by a finger-width at arm's length, is orange Tarazed (Gamma Aquilae), looking like Altair's little sidekick but actually a much bigger and brighter star far in the background. Altair is 17 light-years away. Tarazed is about 360 light-years away, and it puts out 100 times as much light!

As dawn begins to brighten late this week, the waning crescent Moon walks down through Virgo to pose low and thin over Mercury and Spica.


■ Around 10 p.m., depending on where you live, zero-magnitude Capella rises exactly as high in the northeast as zero-magnitude Vega has sunk in the west-northwest. How accurately can you time this event? Sextant not required. . . but it would help.

■ This week Jupiter crosses the meridian (is highest due south) around 7 or 8 p.m. daylight-saving time, depending how far east or west you live in your time zone. And when Jupiter crosses the meridian now, so does the nose star of upside-down Pegasus: Enif, aka Epsilon Pegasi. "Enif" is from the Arabic for nose, a designation adopted from the Greeks' take on Pegasus.

At magnitude 2.4, Enif is easy to spot 25° above Jupiter. That's about 2½ fists at arm's length. Sharp eyes or binoculars reveal that it's yellow-orange; it's a K3 supergiant.

Enif is your starting point for finding the fine fall globular cluster M15, Queen Anne's Lace per Josh Urban, located 5° to the star's northwest (upper right these evenings). At 6th magnitude M15 is within binocular range as a tiny glowball, and a 6-inch telescope may begin to resolve some of its sugarpile starspecks. Use the finder chart with Matt Wedel's Binocular Highlight column in the October Sky & Telescope, page 43.

■ In early dawn Wednesday morning, have a try for the thin Moon, Mercury, and Spica forming a triangle very low in the east-southeast, as shown above. Bring binoculars in case you don't catch just the right, brief time window between the triangle being too low and the sky becoming too bright for Spica, the faintest of the three.


■ Got a really big scope and a dark-sky location? With the Moon gone from the evening sky, bring your deep-sky atlas and check out "The Odd World of Peculiar Galaxies" in the October Sky & Telescope starting on page 57, with photos and visual drawings. The ten featured galaxies are magnitudes 12 to 14.

■ Low in bright dawn Thursday morning, the thin waning Moon hangs in a triangle with Mercury and faint Spica below it, as shown above. Look low in the east-southeast about 40 or 30 minutes before sunrise, and bring binoculars.

The triangle is 4° or 5° on a side. The Moon is thin indeed; it's only 1½ days from new as dawn breaks in the Americas.


■ After dark this week Capella shines well up in the northeast, and the Pleiades are well up in the east-northeast three fists to Capella's right. As evening grows later, you'll find orange Aldebaran climbing up below the Pleiades. By about 10 p.m. (depending on your location), Orion is clearing the eastern horizon below Aldebaran.

■ Uranus is at opposition.


The Summer Triangle Effect. Here it is early November, but Deneb still shines right near the zenith as the stars come out. And brighter Vega is still not far from the zenith, toward the west. The third star of the "Summer" Triangle, Altair, remains very high in the southwest (high upper right of Jupiter and Saturn). They seem to have stayed there for a couple months! Why have they stalled out?

What you're seeing is the result of sunset and darkness arriving earlier and earlier during autumn. Which means if you go out and starwatch soon after dark, you're doing it earlier and earlier by the clock. This counteracts the seasonal westward turning of the constellations.

Of course this "Summer Triangle effect" applies to the entire celestial sphere, not just the Summer Triangle. But the apparent stalling of that bright landmark inspired Sky & Telescope to give the effect that name many years ago, and it has stuck.

Of course, as always in celestial mechanics, a deficit somewhere gets made up elsewhere. The opposite effect makes the seasonal advance of the constellations seem to speed up in early spring. The spring-sky landmarks of Virgo and Corvus seem to dash away westward from week to week almost before you know it, due to darkness falling later and later. Let's call this the "Corvus effect."

■ New Moon (exact at 5:15 p .m. Eastern Daylight Time).

Jupiter and Saturn have passed the stationary points in their retrograde loops and have begun moving eastward (to the left) again with respect to the background stars. This is most noticeable as Jupiter moves past Delta Capricorni, the constellation's left corner, shown here. Keep watch; the planets' eastward motion is speeding up.


■ I don't know why I always get confused trying to find the open cluster NGC 7789 in Cassiopeia, a.k.a. Caroline's Rose, with a finderscope or binoculars. I mean it's right there a simple, short star-hop from the bright end of the Cassiopeia W. Maybe it's because it's a very dim, smooth glow despite being respectably large; the cluster is rich with stars but they're all very faint. Use the nice clear finder chart with Matt Wedel's Binocular Highlight column in the November Sky & Telescope, page 43.

■ Daylight-saving time ends at 2 a.m. tonight for most of North America. Clocks fall back an hour and some of them do it all by themselves, this being the 21st century.


This Week's Planet Roundup

Mercury, in Virgo, is still in its best morning apparition of the year. Look for it low above the east-southeast horizon in early dawn, about 50 to 40 minutes before your sunrise time. It remains bright at magnitude –0.8 all week. Passing through its vicinity is fainter Spica, magnitude +1.0.

On the morning of November 3rd the thin Moon stands close above them, as shown two illustrations above.

Venus, a brilliant magnitude –4.6, shines in southwest during and after twilight, right or lower right of the vastly fainter Sagittarius Teapot. Venus now stays up for nearly an hour after dark. It will continue to get a little higher and brighter into early December.

Mars remains out of sight deep in the glow of sunrise.

Jupiter and Saturn continue to shine in the south during evening, 15° apart in Capricornus. Jupiter is the bright one at magnitude –2.5. Saturn, to its right or lower right, is mag +0.6.

In twilight they're just beginning to tilt. As evening advances they tilt more steeply as they move westward. Saturn sets around 11 or midnight daylight-saving time, Jupiter about an hour later.

Look 23° (two fists at arm's length) lower left of Jupiter for Fomalhaut, magnitude +1.2.

Jupiter on October 6th, imaged by S&T's Sean Walker with a 12-inch reflector in New Hampshire. North is up. "We were treated to some excellent seeing conditions." he writes. "I spent hours shooting and observing the planet, watching the GRS transit, as well as the dark barges in the NEB, and the series of white ovals south of the SEB. It was a magical night of observing."

By the way, fantastically precise velocity measurements of the Juno spacecraft orbiting Jupiter have just shown (via its gravitational perturbations) that the Great Red Spot extends about 300 km below Jupiter's visible cloudtops. This is deeper than was expected, but still very shallow compared to the spot's width of 16,000 km; the great storm is about 50 times wider than deep, a little thinner than two DVDs stacked.

Still, the bottom is below the depth when sunlight penetrates or water condensation occurs. See The Roots of Jupiter's Great Red Spot Run Deep. "For context, Jupiter’s stripes, the brown-red belts and whitish zones, extend much deeper, down to about 3,000 km, or about 4% of the way to the core."

Uranus (magnitude 5.7, in southern Aries) is well up in the east by 9 p.m. It's at opposition this week, exactly so on November 4th. See Bob King's Uranus Queues Up for Opposition.

Neptune (magnitude 7.9, at the Aquarius-Pisces border) is high in the southeast by nightfall. It went through opposition almost two months ago, but at Neptune's distance that hardly matters.

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 that also depend on longitude (mainly Moon positions) are for North America.

Eastern Daylight Time, EDT, is Universal Time minus 4 hours. Universal Time is also known as UT, UTC, GMT, or Z time. To become more expert about time systems than 99% of the people you'll ever meet, see our compact article Time and the Amateur Astronomer.

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 magazine of the American Astronomical Society.

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.

You'll also want a good deep-sky guidebook, such as the big Night Sky Observer's Guide 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



Image of Rod


October 29, 2021 at 9:43 am

Presently clouds and rain at my location. However, the last couple of days I did get out and enjoy some telescope time. Yesterday morning, I viewed the Last Quarter Moon or almost Last Quarter Moon. [Observed 0900-1000 EDT/1300 UT - 1400 UT. Last Quarter Moon 28-Oct-2021 2005 UT/1605 EDT. Enjoyable morning views of the Last Quarter Moon at 31x. Crater details along terminator line like Eratosthenes, Archimedes, Plato, and in the south limb, Moretus crater distinct. Near 0953 EDT/1353 UT, a high-altitude jet leaving a contrail flew across the FOV traveling south, straight across the Moon. Quite a view of the jet and Moon 🙂 This confirms that the Moon is farther away from Earth than jets fly above the Earth 🙂 Virtual Moon Atlas reports the angular size of the Moon 30.46 arcminutes. At 31x, the telescope FOV ~ 1.6 arcminutes. The telescope view resolved ~ 9.6 arcsecond on the lunar surface or about 18 km diameter. 1 arcsecond resolution about 1.9 km diameter given the Moon's distance near 392250 km. There were cirrus clouds this morning with light winds from NE at 3 knots and temperature near 13/14C. Easy morning viewing.]

Several days before that I enjoyed some solar observations using my glass white solar filter and telescope. Active regions Sunspot AR2888, AR2889, AR2887, AR2890, AR2886. reporting on the solar activity too and flares (if you use H-alpha filters).

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mary beth

October 29, 2021 at 12:18 pm

Good morning Rod I’m glad to hear that you got out and enjoyed some clear skies! And yes it’s very good to know that the jet doesn’t fly higher than least for now! When we watch the ISS we joke about it appearing to crash into a star or planet. I checked out the sunspot link on your last post and it was very interesting, thank you for the link. That was incredible!

We’ve had beautiful clear nights and I’ve been enjoying Capella.

Wonder if you this weekend will see, in your telescope, any ghost or witches flying about. I have been seeing extra bats so wondering if the vampires are active. In all seriousness, it is amazing how those bats come out sometime within 30 seconds of the sun set.

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Anthony Barreiro

October 29, 2021 at 5:35 pm

Venus was at dichotomy this week. Half of the side of Venus that faces Earth was lit by the Sun, the other half dark, appearing through a small telescope at low magnification like a waxing quarter Moon -- i.e. Venus' western half was bright and the eastern half dark. But Venus in her closer, faster orbit is swinging around between the Earth and the Sun, so Venus' phase is waning (getting thinner) rather than waxing (getting fatter). Meanwhile, as Venus gets closer to Earth her apparent size is getting bigger. Soon we will be able to see Venus' crescent phase easily through binoculars!

Following Venus through binoculars before and after her inferior conjunction with the Sun every 19 months is one of my favorite easy observing projects. Venus will be at inferior conjunction, directly between the Earth and Sun, January 9, 2022 UTC, January 8 here in North America.

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October 30, 2021 at 2:01 am

Couple of things about the "Summer Triangle" effect and the "Corvus (Virgo)" effect.

1. Right now, sunset is occurring earlier in part because the Sun's path across the sky in mid-Fall to mid-Winter has a smaller arc than it does during mid-Spring to mid-Summer. It's moving the same rate across the sky as the Earth rotates; so it takes less time to travel the shorter distance. However right now the Sun daily change in Right Ascension is less since it is part of its motion is going towards its fast southward change in Declination. This is making Solar Noon occur earlier than "True Noon" (12:00), ands to the earlier occurrence of sunset and twilight.. A similar thing happens in the spring, but in that case it slightly offsets the later occurrences of sunset and twilight, and slightly slows the movement of Corvus and Spica into the Summer evening twilight.

2. There is a morning version of the "Corvus effect" going on right now in the morning sky. Sunrise and morning twilight are occurring ~later~ each morning by a few minutes. Added to Corvus rising 4 minutes ~earlier~ each morning, this means Corvus and Virgo are moving quickly in the pre-dawn sky. Spica was in conjunction with the Sun in mid-October, 2 weeks ago; it rose and set with the Sun, both around 7:00am in Los Angeles (PDT). As of Nov 5 Spica rises around 5:30am (90 minutes earlier than 3 weeks prior), while the sun rises around 7:15am, giving Spica an extra 15 minutes of darkness besides the regular 4-minute diurnal gain.

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Anthony Barreiro

October 30, 2021 at 10:21 pm

Thanks Misha. Now we're primed to understand the equation of time!

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October 31, 2021 at 10:34 pm

Anthony Barreiro report on Venus prompted to view Venus tonight using my telescope. Here is note 🙂 [Observed 1900-2000 EDT/2300-0000 UT. New Moon 04-Nov-2021
2115 UT. Early viewing from 1900-1930 EDT, altocumulus clouds moved rapidly across the sky from the WNW so views of Venus limited and only briefly. Venus getting lower in SW sky too. However, Venus exhibited a lovely half-moon shape at 71x using my 90-mm
refractor telescope with 14-mm eyepiece, and quite bright too. True FOV a bit more than 60 arcminutes. Venus apparent magnitude -4.5. Venus disk illumination 49%. The star HIP86385 ~ 9 arcminute angular separation from Venus according to Starry Night. The star apparent magnitude +7.7 and distance ~ 174 LY. Venus ~ 75900x brighter than the star 🙂 Venus distance 0.651 au according to Stellarium 0.21.2. Both Venus and the star visible in the telescope view behind some trees I looked through. Later after clouds started to clear, Jupiter and the 4 Galilean moons visible with a number of 8th-9th magnitude stars in the FOV (Starry Night and Stellarium show). A number of cloud bands distinct on Jupiter visible and I did not use planetary filters. Saturn quite lovely in Capricornus. Starry Night and Stellarium show a number of 8th to 10th apparent magnitude stars visible in the 60 arcminute FOV. Saturn, rings, and the moons Titan and Rhea visible. This was a lovely view at 71x with the background stars in Capricornus visible. Winds tonight from WNW at 9 knots and temperature near 14C. Earlier when I viewed, rapid moving altocumulus clouds made observing difficult. So tonight I enjoyed views of Venus, Jupiter, and Saturn at 71x using my 90-mm refractor telescope. 4 Galilean moons observed and two moons at Saturn, Titan and Rhea.]

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Anthony Barreiro

November 1, 2021 at 3:13 pm

Thanks for the detailed report. I'm glad you had a look at Venus. Keep watching. Have you observed crescent Venus during previous apparitions?

The sky here in San Francisco has been mostly overcast recently, but at least we're getting some much needed rain.

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November 2, 2021 at 7:05 am

Anthony, yes for Venus crescent views. Here is a *detailed* note from my logs 🙂 The most dramatic views during 2018 when Venus retrograde and I watched :). My log shows 49 Venus observations from Oct-2005 thru May-2020. 4 observations of Venus recorded May-2020 thru Nov-2020 and 2 observations in Oct-2021, a total 55 Venus observations logged. The most dramatic views of Venus and phase changes took place in 2018 when I observed Venus retrograde near the star Spica and switch back to eastward motion. My log for 16-Nov-2018, “This is a note. Venus retrogrades this morning near Spica in Virgo. November issue of Sky & Telescope report by Fred Schaaf is accurate using the heliocentric solar system for the planetary ephemeris. "Venus passed 1.2 degrees from Spica on September 1st, but this month its retrograde motion brings it back to linger less than 1.5 degrees from the star for the mornings of November 12-17." My log for the November 2018 views of Venus. My log for 19-Nov-18 records “Observed 0550-0620 EST. USNO reports sunrise at 0654 EST. Moonset at 0248 EST this morning. Some cirrus interfered with observation, but I could see Venus bright at 17% illuminated and 48 arcsecond size, even in 10x50 binoculars (crescent shape obvious). Spica is no longer visible in the same FoV at 31x and 1.6-degree true field but the star 76 Virginis was about 0.3-degree angular separation. 76 Virginis mv + 5.21, spectral class G8III, stellar parallax 13.87 mas in SIMBAD or about 235 LY distant from earth. Venus stopped retrograding near Spica 17-Nov-2018 and now moving eastward again along the ecliptic. The heliocentric solar system is accurate and correct. Venus distance from earth according to S&T Planetary Almanac on 21-Nov-2018 is 0.349 AU. Venus near 0627 EST, altitude = 22 degrees, 125 degrees azimuth for my location. Starry Night Orion SE 7 shows Venus at 0.34046 AU and 49 arcsecond size, mv -4.60. Venus is 15.26% illuminated this morning according to Starry Night Orion SE 7. Starry Night Orion SE 7 shows 76 Virginis at 264 LY distance and mv +5.18. 264 LY distance is 12.35 mas stellar parallax.”

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November 2, 2021 at 7:38 am

FYI for those reading these posts. I use Sky & Telescope monthly magazine. The November issue on page 44 has ephemeris table for the planets, November 2021 Observing, Planetary Almanac. This shows Venus changes from 01-30 for the month. Tracking Venus brightness, angular size changes, and disk illumination throughout the month can show very rapid changes when observing Venus and using *fixed star* reference points too. A good, small telescope is very useful, views 50 to 100x work nicely. Sometimes I switch to 200x and use a blue planetary filter too. Anthony Barreiro is correct about watching Venus. It can be great fun 🙂

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Anthony Barreiro

November 2, 2021 at 4:53 pm


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November 3, 2021 at 7:41 pm

Beautiful crescent moon this morning (11/3) with Mercury just beneath in crystal clear New Mexico skies.

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November 5, 2021 at 5:58 pm

I am saddened that more "air time" was not given to feature the Nov 3rd occultation of Mercury - a neat rarer even that WAS possible in the mid-west US and central Canada to be sure.

I witnessed this neat event in my APM 25x100ED Binoculars. Really neat to see tiny 85% illuminated Mercury (5.6", and -0.6mag at the time) get covered by such a razor thin 1.8% lunar crescent! Yes - TOTALLY visible here in Manitoba. Had pretty nice skies for the event, and enjoyed first morning views as indicated and then the mid-day encroachment.

This was not for the timid, and while I easily could have used a scope, I wanted the extra challenge. I am glad that I did it in the big binoculars! It was fun to witness!

S&T, next time an event like this happens, please give it more airtime. It WAS a worthy event to feature.

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