#astronomy This Week’s Sky at a Look, September 27 – October 5

September 27, 2019 - Comment

The waxing Moon re-enters the night sky this week, shining with Jupiter on October third. . . . after which with Saturn on the fifth. (The blue 10° scale is in regards to the width of your fist at arm’s size. The Moon’s place is actual for an observer close to the center of North



Moon and Jupiter, Oct. 2-3, 2019

The waxing Moon re-enters the night sky this week, shining with Jupiter on October third.

Moon and Saturn, Oct. 4-5, 2019

. . . after which with Saturn on the fifth. (The blue 10° scale is in regards to the width of your fist at arm’s size. The Moon’s place is actual for an observer close to the center of North America. The obvious sizes of the Moon, planets, and stars are exaggerated for readability.)

Friday, Sept. 27

• Arcturus shines within the west as twilight fades out. Capella, equally vibrant, is barely rising within the north-northeast (relying in your latitude; the farther north you’re the larger will probably be.) They’re each magnitude zero. Later within the night, Arcturus and Capella shine on the identical top of their respective compass instructions.

When will this occur? That is determined by each your latitude and longitude. When it does, flip to look southwest. There will likely be Jupiter at about the identical top (relying in your latitude).

Look south-southeast, and there will likely be 1st-magnitude Fomalhaut about equally excessive too.

Saturday, Sept. 28

• The starry W of Cassiopeia stands excessive within the northeast after darkish. The correct-hand facet of the W, the brightest facet, is tilted up.

Look alongside the second phase of the W counting down from the highest. Discover the dim naked-eye stars alongside that phase (not counting its two ends). The brightest of those, on the proper, is Eta Cassiopeiae, magnitude three.four. It is a Solar-like star simply 19 light-years away with an orange-dwarf companion, a beautiful binary in a telescope.

The “one” on the left, fainter, is a naked-eye pair in a darkish sky: Upsilon1 and Upsilon2 Cassiopeiae, zero.three° aside. They’re orange giants unrelated to one another, 200 and 400 light-years away. Upsilon1, barely fainter, is the farther one.

• New Moon (actual at 2:26 p.m. Jap Daylight Time).

Sunday, Sept. 29

Vertical Milky Way over Estonia

The Milky Approach now stands straight up from the south-southwest horizon after darkish, like firelit smoke rising from a campfire, in case you’re on the planet’s mid-northern latitudes. Robert Sälg took this shot from Vorumaa, Estonia, latitude 58°, fairly far north — which is why the Sagittarius star clouds are so low within the bushes, and why the bluer Cygnus Star Cloud is not as excessive because it “ought to” be. Click on to enlarge.

• Right now of 12 months the wealthy Cygnus Milky Approach crosses the zenith quickly after darkish (for mid-northern latitudes). The Milky Approach extends straight up from the southwest, like firelit smoke from some nice dim campfire. It passes overhead, then runs straight all the way down to the northeast — the place it plummets by way of Cassiopeia, Perseus, and low Auriga.

• Algol in Perseus shines at its minimal brightness (magnitude three.four as a substitute of its standard 2.three) for a pair hours centered on 12:34 a.m. tonight EDT, 9:34 p.m. PDT.

Monday, Sept. 30

• “My favourite observations enable me to make comparisons,” writes Matt Wedel within the October Sky & Telescope: “related objects at completely different distances, or objects of various sizes on the identical distance.” For binocular observers he gives some examples on the bowl of the Sagittarius Teaspoon, simply above vibrant Saturn. See his Binocular Spotlight column on web page 43 of the October difficulty.

Tuesday, Oct. 1

• Within the west, means left of the Massive Dipper, shines vibrant Arcturus, the “Spring Star,” a little bit decrease at dusk every week. From Arcturus, the slender kite-shaped sample of Bootes extends 24° to the higher proper.

Wednesday, Oct. 2

• The crescent Moon at nightfall varieties a triangle with Jupiter to its left and dimmer Antares nearer to the Moon’s decrease left, as proven on the prime of this web page.

• Algol is at its minimal brightness for a pair hours centered on 9:23 p.m. EDT.

Thursday, Oct. three

• The thick crescent Moon this night shines with vibrant Jupiter, as proven on the prime of this web page. Jupiter, although, is 2,200 occasions farther away. Its 4 huge moons, seen in any telescope as fifth and sixth magnitude dots, are roughly our personal Moon’s dimension.

Friday, Oct. four

• Now the waxing Moon shines between Jupiter and Saturn.

Saturday, Oct. 5

• First-quarter Moon (actual at 12:47 p.m. Jap Daylight Time). This night the Moon shines with Saturn, which is just about 2° to its proper or higher proper at nightfall for North America.

However Saturn is three,800 occasions farther away. A telescope this night will present its personal largest satellite tv for pc, Titan, as a magnitude-Eight.7 orange pinpoint 4 ring-lengths to Saturn’s east. But Titan is half once more as giant in diameter as our Moon.

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Wish to turn into a greater astronomer? Be taught your means across the constellations. They’re the important thing to finding the whole lot fainter and deeper to hunt with binoculars or a telescope.

That is an out of doors nature interest. For an easy-to-use constellation information overlaying the entire night sky, use the large month-to-month map within the middle of every difficulty of Sky & Telescope, the important information to astronomy.

Jumbo Pocket Sky Atlas cover

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and lots of of telescopic galaxies, star clusters, and nebulae amongst them. Proven above is the Jumbo Version for simpler studying within the evening. Pattern chart.

When you get a telescope, to place it to good use you may want an in depth, large-scale sky atlas (set of charts). The essential normal is the Pocket Sky Atlas (in both the unique or Jumbo Version), which reveals stars to magnitude 7.6.

Subsequent up is the bigger and deeper Sky Atlas 2000.zero, plotting stars to magnitude Eight.5; almost thrice as many. The subsequent up, as soon as your means round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) and Uranometria 2000.zero (stars to magnitude 9.75). And skim find out how to use sky charts with a telescope.

You will additionally need a good deep-sky guidebook, corresponding to Sue French’s Deep-Sky Wonders assortment (which incorporates its personal charts), Sky Atlas 2000.zero Companion by Robust and Sinnott, or the larger Evening Sky Observer’s Information by Kepple and Sanner.

Can a computerized telescope change charts? Not for learners, I do not suppose, and never on mounts and tripods which can be lower than top-quality mechanically (that means heavy and costly). And as Terence Dickinson and Alan Dyer say of their Yard Astronomer’s Information, “A full appreciation of the universe can not come with out creating the abilities to search out issues within the sky and understanding how the sky works. This information comes solely by spending time underneath the celebrities with star maps in hand.”

This Week’s Planet Roundup

Mercury, Venus, and Mars stay deep within the glare of the Solar.

Jupiter (magnitude –2.zero, between the toes of Ophiuchus) is the white dot low within the southwest as twilight fades away. Orange Antares, one sixteenth as vibrant at magnitude +1.zero, twinkles 10° to Jupiter’s decrease proper.

This can be a awful time for Jupiter telescopically. Not solely is the low-altitude seeing a large number, however Jupiter has shrunk to only 36 arcseconds huge.

Saturn this week stays low over the Sagittarius Teapot.

Saturn (magnitude +zero.5, in Sagittarius) is the regular yellow “star” within the south throughout and after nightfall. It is 26° higher left of Jupiter. Beneath Saturn is the deal with of the Sagittarius Teapot. Barely above it’s the dimmer, smaller bowl of the Sagittarius Teaspoon.

Uranus (magnitude 5.7, in Aries) is nicely up within the east by 10 p.m. daylight saving time. It is highest within the south round 2 a.m.

Neptune (magnitude 7.Eight, in Aquarius) is within the southeast after darkish and highest within the south round 11 p.m. See Bob King’s story on observing Neptune and our finder charts for Uranus and Neptune.

All descriptions that relate to your horizon — together with the phrases up, down, proper, and left — are written for the world’s mid-northern latitudes. Descriptions that additionally rely upon longitude (primarily Moon positions) are for North America.

Jap Daylight Time (EDT) is Common Time (UT, UTC, GMT, or Z time) minus four hours.

Audio sky tour. Out underneath the night sky along with your earbuds in place, hearken to Kelly Beatty’s month-to-month podcast tour of the heavens above. It is free.

“The risks of not considering clearly are a lot better now than ever earlier than. It isn’t that there is one thing new in our mind-set, it is that credulous and confused considering may be way more deadly in methods it was by no means earlier than.”
— Carl Sagan, 1996



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