It takes large optics and excellent seeing (or adaptive optics) to catch cloud options on the distant ice giant Neptune. Nonetheless, one of the best time to see it’s as opposition week. Credit score: ESO/P. Weilbacher (AIP)
Friday, September 15
Saturn’s largest and brightest moon, Titan, is passing south of the ringed planet in a single day. You could find Saturn as quickly because the sky grows darkish after sundown, glowing a mushy magnitude 0.5 in Aquarius. By two hours after sundown, the planet is simply over 25° excessive within the southeast, some 19.5° above 1st-magnitude Fomalhaut in Piscis Austrinus.
Zoom in on Saturn with a telescope to first view its attractive ring system, now tilted towards Earth by about 10°. The rings stretch 42″, whereas the disk of the planet spans practically 20″. Arrayed across the planet are a number of moons — Titan is the brightest, glowing round magnitude 8.5. It’s situated southeast of Saturn within the early night, very slowly shifting west. It should cross due south of the planet throughout daytime on the sixteenth.
Different moons seen embrace Tenth-magnitude Tethys, Dione, and Rhea. The primary two sit near the planet’s disk, simply west of the limb and south of the rings. They proceed shifting west in a single day. Rhea lies far to the east, practically 1.5′ from of the middle of the planet; it seems to remain in the identical location all evening.
Cautious observers may spot Mimas and its shadow crossing in entrance of the disk from about 2 A.M. EDT on the sixteenth (nonetheless late on the fifteenth in western time zones) to shortly earlier than 4 A.M. EDT on the sixteenth. The moon and its shadow are small and faint in comparison with the disk, so excessive magnification and regular seeing will up your possibilities — or you may attempt to seize the occasion photographically or utilizing high-speed video.
Dawn: 6:41 A.M.
Sundown: 7:09 P.M.
Moonrise: 7:06 A.M.
Moonset: 7:38 P.M.
Moon Part: New
*Instances for dawn, sundown, moonrise, and moonset are given in native time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. native time from the identical location.
Saturday, September 16
The Moon passes 0.7° north of Mars at 3 P.M. EDT. From the japanese half of the U.S., the Moon passes solely in entrance of Mars in an occasion known as an occultation that happens in daylight across the similar time. Skilled observers who wish to catch the occasion ought to accomplish that rigorously — strive organising and calibrating your telescope’s go-to system early within the morning earlier than dawn so you may guarantee it’s monitoring correctly, and by no means look by means of the eyepiece or finder scope whereas it’s shifting. Even a short, unintentional glimpse of the Solar may critically and completely injury your eyes.
For a lot simpler — and safer — viewing, the pair hangs about 8° excessive within the west at sundown. They’re now roughly 2° aside, with the Moon situated to Mars’ higher left (east). Our satellite is a mere 4-percent-lit waxing crescent — are you able to see the fragile sliver of the japanese limb instantly lit by the Solar? You may also discover that the darkish face nonetheless in shadow is seen, because of a phenomenon known as earthshine. This happens when daylight bounces off Earth and illuminates the portion of the Moon not below direct daylight. Binoculars or a telescope can assist carry out element on the skinny crescent earlier than it units.
Simply west of the Moon is Mars, glowing at magnitude 1.7. Via a telescope, it seems absolutely lit and spans simply 4″. The Purple Planet now lies some 2.5 astronomical models from Earth (1 astronomical unit, or AU, is the common Earth-Solar distance).
Because the area sinks, you may see 1st-magnitude Spica seem about 10° to the higher left of the Moon and Mars because the sky grows darker. And a few 30° above them is brighter Arcturus in Boötes, shining at magnitude 0.
Dawn: 6:42 A.M.
Sundown: 7:07 P.M.
Moonrise: 8:06 A.M.
Moonset: 7:57 P.M.
Moon Part: Waxing crescent (3%)
Sunday, September 17
Neptune reaches opposition at 7 A.M. EDT. Now’s one of the best time to view probably the most distant planet in our solar system, which at the moment lies practically 29 AU from Earth. The planet is rising within the east amid the celebrities of Pisces at sundown, so wait an hour or two for the sky to darken and the area to climb out of the turbulent air close to the horizon. At opposition Neptune rises round sundown and units round dawn. This offers you a variety of viewing alternatives that may proceed for weeks to come back.
Round 10 P.M. native daylight time, Neptune is 30° excessive within the east, hanging simply beneath the Circlet asterism in Pisces. You’ll discover it by means of binoculars or with a telescope some 4.7° south-southeast of Lambda (λ) Piscium. Tonight, the ice giant sits a mere 10′ due west of a Fifth-magnitude discipline star, HD 15313 (additionally cataloged as HIP 11375). Via your optics, Neptune will merely appear to be a “flat” star or tiny disk simply 2″ vast. In actuality, it’s a large world some 17 occasions the mass of Earth and virtually 4 occasions as vast as our planet.
Venus reaches its best illuminated extent at 10 A.M. EDT, when it’s magnitude –4.8. If you happen to’re nonetheless up after an evening of Neptune observing, you’ll see Venus rise within the east about three hours earlier than the Solar, situated in southeastern Most cancers close to the constellation’s 4th-magnitude alpha star. The intense planet hangs some 10° under the naked-eye Beehive Cluster (M44), providing gorgeous views earlier than twilight brightens the sky an excessive amount of.
Dawn: 6:43 A.M.
Sundown: 7:06 P.M.
Moonrise: 9:08 A.M.
Moonset: 8:18 P.M.
Moon Part: Waxing crescent (6%)
Monday, September 18
An early-morning occultation of Ganymede by its father or mother world Jupiter will greet observers within the japanese half of the U.S. immediately.
The occasion kicks off shortly earlier than 12:30 A.M. EDT, so observe that is nonetheless late on the seventeenth in all different time zones. At the moment, Jupiter is a few 45° excessive within the east, situated in southeastern Aries. It’s the brightest object within the area, its magnitude –2.7 mild outshining the constellation’s faint stars. Prepare your telescope on Jupiter round 12:20 A.M. EDT to make sure you don’t miss the beginning, as vibrant Ganymede approaches the planet’s northern limb from the west. The moon ought to begin to disappear behind the limb just some minutes later — however slowly, because of its measurement mixed with the shallow angle at which we’re viewing the occasion.
It takes about an hour for Ganymede to reappear, slipping out from behind the disk at 1:22 A.M. EDT. The entire sequence is greatest seen from the East Coast and the Midwest, because the planet shall be decrease within the sky for observers farther west (although should you can catch it, significantly from a better elevation, do strive). Keep in mind that the farther west your time zone, the extra probably it’s that this occasion will happen late on the seventeenth, moderately than early on the 18th.
Because the hours progress into the morning of the 18th, there’s one other occasion to be careful for: Whereas Ganymede pulls away to the east, Io is approaching from the east for a transit. Its shadow seems on the cloud tops first, shifting inward from the japanese limb round 5:10 A.M. EDT. Io follows swimsuit, passing in entrance of the disk beginning round 6:10 EDT, shortly earlier than dawn on the East Coast. Now these in western time zones have a bonus, as they’ll watch the shadow and moon cross the planet. The shadow disappears simply earlier than 6:15 A.M. CDT, not lengthy earlier than dawn within the Midwest. The moon continues its journey, lastly shifting off the disk round 6:15 A.M. MDT.
Dawn: 6:43 A.M.
Sundown: 7:04 P.M.
Moonrise: 10:11 A.M.
Moonset: 8:42 P.M.
Moon Part: Waxing crescent (12%)
Tuesday, September 19
Though Comet Nishimura has left our skies, there are many different comets to get pleasure from, albeit ones that require a telescope to see. One is Comet 103P/Hartley 2, now rising late at evening within the constellation Auriga. You’ll be able to catch it in a single day beginning round midnight and persevering with into the early-morning hours, climbing highest within the northeast within the few hours earlier than daybreak.
Now about Tenth magnitude, Hartley 2 is passing simply 2° southeast of Third-magnitude Eta (η) Aurigae, placing it about 6.5° due south of the intense (magnitude 0.1) star Capella. At present the comet additionally lies about 2° west of the open cluster NGC 1857, a Seventh-magnitude grouping of younger stars overlaying about 4.5′ of sky. A medium discipline of view ought to present each, making for an excellent scene to {photograph} should you’re ready. Additionally close by — about 3.4° southwest of NGC 1857 — is one other open cluster, NGC 1778. This group of stars covers about the identical space of sky however is a bit fainter, round magnitude 7.7.
Hartley 2 remains to be brightening and will attain magnitude 7.5 subsequent month.
Dawn: 6:44 A.M.
Sundown: 7:02 P.M.
Moonrise: 11:17 A.M.
Moonset: 9:11 P.M.
Moon Part: Waxing crescent (19%)
Wednesday, September 20
Excessive within the south this night is the constellation Vulpecula the Fox. A couple of hours after sundown, it lies instantly above Aquila the Eagle, whose vibrant star Altair is a part of the well-known Summer season Triangle asterism. The small constellation Sagitta the Arrow is sandwiched between them.
Vulpecula homes a very well-known deep-sky marvel: the Dumbbell Nebula (M27). This stunning planetary nebula is the results of an getting old star blowing away its outer layers, then lighting up the thrown-off fuel from the within out. The Dumbbell sits about 2° southeast of 13 Vulpeculae, a Fifth-magnitude star. Alternatively, you should use magnitude 3.5 Gamma (γ) Sagittae to search out it, as M27 is 3.2° due north of this star.
Even by means of 10x binoculars, the Dumbbell ought to look noticeably rectangular. Bump up the magnification for a bit extra element. The Dumbbell shines at magnitude 7.3 and is pretty giant (about 8′ lengthy alongside its lengthy axis), making it an excellent object even for smaller scopes. See should you can spot the 2 barely brighter areas of nebulosity at both finish, which give the nebula its bowtie or dumbbell form.
Dawn: 6:45 A.M.
Sundown: 7:01 P.M.
Moonrise: 12:25 P.M.
Moonset: 9:46 P.M.
Moon Part: Waxing crescent (28%)
Thursday, September 21
The Moon passes 0.9° north of Antares at 4 A.M. EDT, although neither object is seen at the moment. As a substitute, look south an hour after sundown to see the 2 now practically 9° aside. In reality, the Moon has handed out of Scorpius — which homes Antares — and now resides in southern Ophiuchus, to Scorpius’ east. Not like earlier within the week, Luna is now a 42-percent-lit crescent, rapidly waxing towards First Quarter, which it’ll attain tomorrow.
However let’s deal with Antares, the intense, glowing pink coronary heart of the Scorpion. This 1st-magnitude pink large lies close to the wealthy globular cluster M4, simply 1.3° to Antares’ west. At magnitude 5.6, this cluster might be glimpsed with the bare eye below good skies; it spans simply over half a level and plenty of of its stars might be resolved even in a small (4-inch) scope. It’s not too troublesome to seize gorgeous photographs of the cluster with Antares close by, and images also can choose up the nebulosity round Antares, cataloged as IC 4606. The sunshine comes from ionized hydrogen fuel, which is energized by the star in order that it glows.
Barely nearer to Antares (simply 40′ to its northwest) is one other globular cluster, NGC 6144. This grouping is fainter and rather more compact than M4. NGC 6144 covers simply 10′ of sky and shining a fainter magnitude 9.1. Deep astrophotos present it embedded inside the glow of the hydrogen fuel lit by Antares.
Dawn: 6:46 A.M.
Sundown: 6:59 P.M.
Moonrise: 1:35 P.M.
Moonset: 10:30 P.M.
Moon Part: Waxing crescent (38%)
Friday, September 22
Mercury reaches best western elongation of 18° at 9 A.M. EDT. The small planet now seems within the predawn sky with Venus.
You’ll discover Mercury in Leo, located close to the Lion’s again half and rising about an hour and a half earlier than the Solar. An hour earlier than dawn, Mercury is 5° excessive and climbing, hanging under and simply to the left of the intense star Regulus. The planet shines at –0.3, a couple of full magnitude brighter than the magnitude 1.4 star. Venus, in the meantime, nonetheless blazes at magnitude –4.8, however not for lengthy — inside two days, it’ll dim simply barely to magnitude –4.7 (admittedly a change that’s indistinguishable to the attention). The brighter planet stays in Most cancers, on the western finish of an east-west line with Mercury on the japanese finish and Regulus between the 2 planets.
Via a telescope, Mercury now spans 7″ and is 48 % lit. Against this, Venus seems enormous — 36″ throughout — however now simply 30 % lit. Venus is each bodily bigger than Mercury and likewise nearer to Earth: Venus lies 0.46 AU from us, whereas Mercury is 0.95 AU from Earth.
First Quarter Moon happens this afternoon at 3:32 P.M. EDT.
Dawn: 6: 47 A.M.
Sundown: 6:57 P.M.
Moonrise: 2:40 P.M.
Moonset: 11:26 P.M.
Moon Part: Waxing crescent (49%)
Sky This Week is dropped at you partly by Celestron.
