Tuesday, January 14, 2020
The Sky This Week - Thursday January 16 to Thursday January 23
The Last Quarter Moon is Friday, January 17. Venus is prominent in the evening sky visible well after twilight. Mars is visible in the morning twilight in the head of Scorpius the Scorpion close to some bright stars. On the 21st the crescent Moon, Mars and the bright red star Antares form a line. On the 23rd the crescent Moon and Jupiter are close. The Red Giant star Betelgeuse in Orion is still dimming.
The Last Quarter Moon is Friday, January 17.
Sky at 21:35 ACDST on Saturday, January 18 (60 minutes after sunset)
looking west as seen from Adelaide. Venus is prominent in the sky. The inset shows the telescopic view at this time.
Similar views will be seen elsewhere in Australia 60 minutes after sunset, click to embiggen.
Morning sky at 5:20 ACDST facing east as seen from Adelaide on Tuesday, January 21, 60 minutes before sunrise.
Mars is now well above the horizon and is close to the body of Scorpius the scorpion. Mars is coming close to the bright red star Antares (the rival of Mars). On the 21st the crescent Moon, Mars and Antares form a line.
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Morning sky at 5:22 ACDST facing east as seen from Adelaide on Thursday, January 23, 60 minutes before sunrise.
Jupiter is low above the horizon underneath the tail of Scorpius the scorpion. On the 23rd the thin crescent Moon is near Jupiter.
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Evening sky looking north-east at 22:12 ACDST on Saturday, January 18 (90 minutes after sunset). Similar views will be seen elsewhere in Australia at the equivalent local time. Orion is readily visible. Betelgeuse is the bright red star below the "saucepan" of Orion. Red Aldebaran is almost the same height above the horizon as red Betelgeuse, making brightness comparisons easy.
Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion. It is a variable star, with small fluctuations in brightness not visible to the casual observer.
Betelgeuse has dimmed substantially and is now even dimmer than last week, reportedly between magnitude 1.5-1.7, it is visibly dimmer than magnitude 1 Aldebaran and roughly as bright as Bellatrix. The next brightest star just to the north of Betelgeuse. Keep an eye on this historic dimming event, observing hints and stars for magnitude estimation are given here. The waning moon will be out of the way making it easier to estimate Belegeuses brightness.
Venus is prominent above the western horizon in the early evening sky. Venus is now readily seen up to 90 minutes after sunset.
Mercury is obscure in the twilight.
Jupiter enters the morning sky and is close to the crescent Moon on the 23rd low in the twilight.
Mars is visible high in the morning twilight. It is near the scorpion, Scorpius, this week. It is close to the bright red star Antares (the rival of Mars). On the 21st the crescent Moon, Mars and Antares form a line.
Saturn is in conjunction with the Sun on the 14th and will not become visible until it enters the morning sky in February.
Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.
Star Map via Virtual sky. Use your mouse to scroll around and press 8 when your pointer is in the map to set to current time.
Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
The Last Quarter Moon is Friday, January 17.
Sky at 21:35 ACDST on Saturday, January 18 (60 minutes after sunset)
looking west as seen from Adelaide. Venus is prominent in the sky. The inset shows the telescopic view at this time.Similar views will be seen elsewhere in Australia 60 minutes after sunset, click to embiggen.
Morning sky at 5:20 ACDST facing east as seen from Adelaide on Tuesday, January 21, 60 minutes before sunrise.Mars is now well above the horizon and is close to the body of Scorpius the scorpion. Mars is coming close to the bright red star Antares (the rival of Mars). On the 21st the crescent Moon, Mars and Antares form a line.
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Jupiter is low above the horizon underneath the tail of Scorpius the scorpion. On the 23rd the thin crescent Moon is near Jupiter.
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion. It is a variable star, with small fluctuations in brightness not visible to the casual observer.
Betelgeuse has dimmed substantially and is now even dimmer than last week, reportedly between magnitude 1.5-1.7, it is visibly dimmer than magnitude 1 Aldebaran and roughly as bright as Bellatrix. The next brightest star just to the north of Betelgeuse. Keep an eye on this historic dimming event, observing hints and stars for magnitude estimation are given here. The waning moon will be out of the way making it easier to estimate Belegeuses brightness.
Venus is prominent above the western horizon in the early evening sky. Venus is now readily seen up to 90 minutes after sunset.
Mercury is obscure in the twilight.
Jupiter enters the morning sky and is close to the crescent Moon on the 23rd low in the twilight.
Mars is visible high in the morning twilight. It is near the scorpion, Scorpius, this week. It is close to the bright red star Antares (the rival of Mars). On the 21st the crescent Moon, Mars and Antares form a line.
Saturn is in conjunction with the Sun on the 14th and will not become visible until it enters the morning sky in February.
Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.
Star Map via Virtual sky. Use your mouse to scroll around and press 8 when your pointer is in the map to set to current time.
Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
Labels: weekly sky
2020: From "Super" Moon to "Mini" Moon and back, a year of full Moons
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| Full Moon January 11, 0:500 AEDST Penumbral eclipse | Full Moon February 09 18:33, perigee + 36h (Feb 11). Minimum libration -2h | Full Moon March 10 04:48 AEDST, Perigee +12h March 10. Minimum libration. |
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| Full Moon April 08 12:35, perigee April 08 + 8h | Full Moon May 07 20:45, perigee April 06 -19h Minimum libration. | Full Moon June 06 05:00, Penumbral eclipse 05:25 |
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| Full Moon July 05 15:00. | Full Moon August 04 02:00. | Full Moon September 02 15:00. Maximum Libration +11 h |
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| Full Moon October 2 07:00, | Full Moon October 31 (WA only, Blue Moon for WA 23:00 AWST) (apogee 05:47 AEDST) | Full Moon November 1 02:00, apogee -20h. Minimum libration +27h |
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| Full Moon November 30 21:00 Blue Moon, all states except WA Penumbral eclipse Eastern states 19:43 Minimum libration | Full Moon December 30 14:00 | Full Moon 2021 January 30 06:19 |
A year of full Moons showing the variation in size as the moons move from perigee to apogee. All the moons are shown on the day and time they are full (unless they are below the horizon, in which caase the size at astronomical twilight is shown), and although this is not the optimal time for size comparisons, you can clearly see the size difference over the year (compare April 8 to October 31) the original scale for all is 2 degrees of field of view cropped down to about two lunar diameters width). Although the field rotation of the Moon makes it less clear, you can also see the effect of libration.
In 2020 we have two Perigee Moon is a row (or four if you cont the Feb and May ones which only barely scrape in as perigee Moons). However, as you can see the differences are subtle, and it requires a keen eye and good memory to distinguish a perigee "super" Moon from more ordinary moons, the best contrast is with the apogee "mini" moon of October 31/November 1).
That doesn't mean you shouldn't try though. Daniel Fischer has been able to see the difference, you can read his account and viewing tips here
http://earthsky.org/space/can-you-discern-supermoons-large-size-with-the-eye-an-observer-says-yes
Photographing them can be more rewarding. You can see images of perigee Moon and apogee Moon pairs from 21 Jan 2019 here and 10 August 2014 here.Tips for photographing them are here.
There is also a "Blue" Moon. On October 31 in WA and November 30 in the rest of Australia (due to time Zones).
Labels: apogee, Blue Moon, Moon, perigee
Sunday, January 12, 2020
Images from the penumbral eclipse of 11 January 2020
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| Moon taken with my Xperia mobile phone at 3:13 am, before the start of the annular eclipse. All images were taken with no digital zoom, f/2. ISO 800, 1/4000 second exposure using infinity to infinity focusing with 20 mm lens and a 4.5" Newtonian scope. | 4:07, 20 minutes after the penumbral eclipse has started, note the faint darkening of the Moon (prior to this I had to move my scope and reset up, painful) |
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| 4:27, the darkening is now clear in both the telescope and to the unaided eye. | 4:48, After an interval with cloud and another shuffle to avoid the moon going behind trees the darkening of the Moon is now clear. |
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| 4:59 after another bout of cloud the darkening is even clearer. After this the clouds came over solidly so I gave up 40 minutes before mid eclipse | Simulation of the shadow at mid-eclipse (not so dark in the simulation but give an idea of the positioning). |
After the sky being clouded out all day and most of the night when I checked the sky in the morning and it was clear as a bell, so I hastily set up my equipment and started imaging. Because of the low altitude of the Moon there was a lot of interference from the trees, which meant I had to move the telescope a lot and re-adjust the camera (hence big gaps the the coverage). Then cloud started coming over, I did get a fair way into the eclipse before the cloud completely wiped it out, but by the time I gave up the darkening of the Moon was obvious both in camera and by eye.
Unfortunately this is the best and darkest of the penumbral eclipses this year for Australia (although the November penumbral eclipse favours the east coast, it is not very dark).
Labels: astrophotography, eclipse, Moon, penumbral, unaided eye
Saturday, January 11, 2020
Southern Skywatch January 2020 edition is now out!
The January edition of Southern Skywatch is now up.
Mercury is low in the evening sky this month and is essentially unobservable.
Venus is high in the evening sky and is visited by the crescent Moon on the 28th.
Mars climbs higher in the morning sky and is visited by the crescent Moon on the 21st.
Jupiter climbs higher in the morning sky from mid-month and is visited by the crescent Moon on the 23rd
Saturn is not visible this Month.
January 5; Earth at perihelion. January 8, Mars near Acrab, January 10, Mars very close to Omgea 1 and 2 Scorpii, January 11, penumbral eclipse of the Moon. January 21; Mars and crescent Moon close. January 23, Jupiter and the thin crescent Moon close in the twilight. January 26, thin crescent Moon and Mercury close with Venus above. January 27, Venus and Neptune close. January 28; crescent Moon and Venus close.
January 2; Moon at Apogee, January 14; Moon at perigee.
Labels: southern skywatch
Friday, January 10, 2020
Disappointing penumbral Eclipse of the Moon, morning Saturday January 11, 2020
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| Western horizon as seen from Sydney on January 11 at 3:06 am AEDST. The eclipse is about to start. Click to embiggen | Western horizon as seen from Adelaide on January 11 at 2:36 am ACDST. The eclipse is about to start. Click to embiggen | Western horizon as seen from Perth on January 11 at 3:10 am AWST. The eclipse is at its maximum extent. Click to embiggen |
This year sees three penumbral lunar eclipses, unfortunately, they are all very poor. On the morning Saturday, January 11 the first of these eclipses will occur. Although this is a relatively deep penumbral eclipse, for most of Australia dawn occurs before mid-eclipse, with only WA and NT seeing the Moon at its darkest. Even for WAa nd NT the subtle darkening of the Moon as it passes through Earth's shadow may be hard to distinguish.
Unfortunately, the January 11 eclipse occurs in the early morning. Even though it is on a Saturday you may wish to stay in bed for this one (WA and NT excluded). Bushfire smoke is an added disincentive for those of us in SA, VIC and NSW.
You don't need special filters or fancy equipment to watch the lunar eclipse, you just need your eyes and somewhere comfortable to sit and watch. Watching the faint outer shadow of earth creep across the Moons face is quite challenging, as the darkening is subtle, but those in WA and NT may find it rewarding (I have with past penumbral eclipses). The Moon is very obvious to the west.
A guide I wrote for the October 2014 lunar eclipse to taking photos of the eclipse is here.
On the East coast, the eclipse starts when the sky is quite dark at 4:06 am AEDST and mid-eclipse begins after Moon set.
In the central states, the eclipse starts before astronomical twilight at 2:36 am ACST (3:36 ACDST) and mid-eclipse begins during twilight in SA and before twilight in NT (NT has a better view than SA due to eclipse geometry, see the map link below).
In WA, the eclipse starts with the Moon quite high, well before astronomical twilight and most of the eclipse is seen. The eclipse starts at 1:06 am AWST and mid-eclipse begins at 3:30 am AWST.
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| Moon as seen from WA January 11 when at mid-eclipse, note the subtle darkening seen on the penumbrally eclipsed Moon compared to February's full Moon. | Comparison Moon as seen from WA February 11 at the same time. |
See here for a map and contact timings in Universal Time for sites outside Australia.
| City | Astronomical twilight | Nautical twilight | Civil Twilight | Moonset | Eclipse Start | Maximum Eclipse | Eclipse End | |
| South Australia (ACDST) | 4:29 am | 5:08 am | 5:44 am | 6:14 am | 3:36 am | 5:40 am | 7:44 am | Max eclipse at civil twilight |
| Northern Territory (ACST) | 5:12 am | 5:39 am | 6:06 am | 6:36 am | 2:36 am | 4:40 am | 6:44 am | Max eclipse before twilight |
| Eastern States (AEDST) | 4:13 am | 4:51 am | 5:26 am | 5:56 am | 4:06 am | 6:10 am | after Moonset | Max eclipse after Moon set |
| Western Australia (AWST) | 3:43 am | 4:19 am | 4:53 am | 5:27 am | 1:06 am | 3:06 am | 5:14 am | eclipse ends close to sunrise and moon set |
Weather: Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
Labels: eclipse, Moon, unaided eye
Thursday, January 09, 2020
Coming Events: A Year of Southern Astronomy for 2020
The table below shows significant astronomical events that can be seen with the unaided eye or minimal equipment in 2020 in Australia (and to some degree elsewhere in the Southern Hemisphere, ocultations and eclipses are very region specific). This year we only get penumbral Lunar eclipses under very poor conditions. There is a very good opposition of Mars though, and a spectacular Jupiter and Saturn conjunction. Venus travels through the Pleiades and displays its crescent form.
Close pairings of the Moon and bright planets are given special attention as not only is the Moon a ready guide to locating the planets if you are not familiar with them, these massings are rather beautiful.
Special events are bolded.
| Date | Event |
| January | |
| 11 January 2020 | Penumbral lunar eclipse in the morning, close to dawn. |
| 21 January 2020 | Crescent Moon and Mars close in the morning |
| 23 January 2020 | Crescent Moon and Jupiter close in the morning |
| 27 January 2020 | Venus and Neptune close |
| 26 January 2020 | Mercury close to the crescent moon in the evening twilight |
| 28 January 2020 | Venus close to the crescent moon in the evening |
| February | |
| 18 February 2020 | Mars passes between the triffid and Lagoon Nebulae |
| 19 February 2020 | Waxing Moon close to Mars in the morning |
| 20 February 2020 | Waxing Moon extremely close to Jupiter in the morning |
| 21 February 2020 | Waxing Moon close to Saturn in the morning |
| 27 February 2020 | Waning Crescent Moon close to Venus |
| 29 February 2020 | Mars close to Globular cluster M22 |
| March | |
| 1 March 2020 | Mars still close to Globular cluster M22 |
| 8-9 March 2020 | Venus close to Uranus (binocular only) |
| 18 March 2020 | Waning Crescent Moon forms a line with Mars, Jupiter and Saturn in the morning sky |
| 19 March 2020 | Crescent Moon between Mars and Jupiter and Saturn |
| 20 March 2020 | Earth at Equinox |
| 21 March 2020 | Mars very close to Jupiter |
| 22 March 2020 | Mercury close to the crescent Moon in the morning |
| 29March 2020 | Venus close to the crescent Moon in the evening |
| April | |
| 1 April 2020 | Saturn close to Mars in the morning sky |
| 3-4 April 2020 | Venus passes through the Pleiades cluster |
| 4 April 2020 | Mercury close to Neptune |
| 8 April 2020 | Perigee Full Moon ("super" Moon), 3:10 am |
| 15 April 2020 | waning Moon close to Jupiter in the morning sky |
| 16 April 2020 | waning Moon close to Saturn in the morning sky |
| 22 April 2020 | Crescent Moon close to Mercury in the morning sky |
| 26-27 April 2020 | Crescent Moon near Venus in the evening sky |
| May | |
| 5 May 2020 | Eta Aquariid meteor shower |
| 12 May 2020 | Moon between Jupiter and Saturn in evening sky |
| 15-16 May 2020 | Mars near the waning Moon |
| 22 May 2020 | Mercury and Venus close |
| 24 May 2020 | Thin crescent Moon near Venus |
| June | |
| 6 June 2020 | Penumbral lunar eclipse early morning near dawn |
| 8 June 2020 | Moon and Jupiter close in evening |
| 9 June 2020 | waning Moon and Saturn close in evening |
| 13 June 2020 | Moon and Mars close in morning |
| 19 June 2020 | Thin crescent Moon and Venus close in the morning twilight |
| July | |
| 5 July 2020 | Jupiter close to the moon |
| 6 July 2020 | Moon and Saturn close |
| 11 July 2020 | Moon and Mars close in evening |
| 12 July 2020 | Moon close to bright star Aldebaran |
| 14 July 2020 | Jupiter at Opposition |
| 17 July 2020 | Thin crescent Moon near Venus in the morning |
| 21 July 2020 | Saturn at Opposition |
| 29 July 2020 | Southern Delta Aquarids meteor shower |
| August | |
| 2 August 2020 | Moon between Jupiter and Saturn |
| 9 August 2020 | Moon close to Mars |
| 15-16 August 2020 | Crescent Moon close to Venus |
| 28 August 20 | Asteroid Ceres at opposition (binoculars only) |
| 29 August 2020 | Moon between Jupiter and Saturn again |
| September | |
| 5-6 September 2020 | Mars close to the Moon |
| 14 September 2020 | Venus and crescent Moon close in morning sky |
| 19 September 2020 | Crescent Moon and Mercury close forming triangle with Spica |
| 24 September 2020 | Variable star Mira at its brightest |
| 22 September 2020 | Mercury and bright star Spica very close |
| 22 September 2020 | Earth at Equinox |
| 25 September 2020 | Waxing Moon, Jupiter form a triangle with Saturn |
| 30 September 2020 | Venus close to bright star Regulus |
| October | |
| 2-3 October 2020 | Mars and waning Moon close |
| 3 October 2020 | Venus and the bright star Regulus very close |
| 14 October 2020 | Venus and the crescent Moon close |
| 14 October 2020 | Mars at opposition |
| 18 October 2020 | Mercury and thin crescent Moon closeish in the evening twilight |
| 21 October 2020 | Orionid meteor shower |
| 22 October 2020 | Jupiter and waning Moon close |
| 23 October 2020 | Saturn and waning Moon close |
| 31 October 2020 | Blue Moon in WA. |
| November | |
| 1 November 2020 | Apogee Full Moon (mini-Moon). In WA full Moon occurs before midnight but for all states apogee is on the early morning of the 1st. |
| 13 November 2020 | Thin crescent Moon close to Venus |
| 14 November 2020 | Thin crescent Moon close to Mercury |
| 18 November 2020 | Leonid Meteor Shower |
| 19 November 2020 | Crescent Moon and Jupiter close forming triangle with Saturn |
| 24-25 November 2020 | Waxing Moon close to Mars |
| 30 November 2020 | Penumbral Lunar eclipse, only seen from eastern states. Blue Moon of all states except WA. (see above) |
| December | |
| 13 December 2020 | Venus and thin crescent Moon close |
| 14 December 2020 | Geminid Meteor shower (New Moon, good rates) |
| 17 December 2020 | Jupiter and Saturn spectacularly close with the thin crescent Moon close too. |
| 21 December 2020 | Jupiter and Saturn even more spectacularly close in a conjunction that will not be repeated for over a decade. The pair will easily be visible together in telescope eye pieces. |
| 21 December 2020 | Earth is at Solstice |
| 23-24 December 2020 | Waxing Moon close to Mars |
Labels: asteroids, Conjunction, eclipse, Jupiter, Mars, Mercury, Meteors, Opposition, Saturn, unaided eye, Venus, Yearly Sky Events
Tuesday, January 07, 2020
The Sky This Week - Thursday January 9 to Thursday January 16
The Full Moon is Saturday, January 11. Penumbral lunar eclipse morning January 11.Venus is prominent in the evening sky visible well after the of twilight. Mars is visible in the morning twilight in the head of Scorpius the Scorpion close to some bright stars. The Red Giant star Betelgeuse in Orion is still dimming.
The Full Moon is Saturday, January 11. Penumbral lunar eclipse morning January 11 The Moon is at perigee when it is closest to the Earth on January the 14th.
Sky at 21:38 ACDST on Saturday, January 11(60 minutes after sunset)
looking west as seen from Adelaide. Venus is prominent in the sky. The inset shows the telescopic view at this time.
Similar views will be seen elsewhere in Australia 60 minutes after sunset, click to embiggen.
Morning sky at 5:08 ACDST facing east as seen from Adelaide on Saturday, January 11, 60 minutes before sunrise.
Mars is low above the horizon and is in the head of Scorpius the scorpion. It is close to the stars Omega 1 and 2 Scorpii on the 9th and 10th. The inset shows the telescopic view of Mars on the 10th (10mm eyepiece 6" reflector).
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Evening sky looking north-east at 22:17 ACDST on Saturday, January 11 (90 minutes after sunset). Similar views will be seen elsewhere in Australia at the equivalent local time. Orion is readily visible. Betelgeuse is the bright red star below the "saucepan" of Orion. Red Aldebaran is almost the same height above the horizon as red Betelgeuse, making brightness comparisons easy.
Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion. It is a variable star, with small fluctuations in brightness not visible to the casual observer.
Betelgeuse has dimmed substantially and is now even dimmer than last week, reportedly between magnitude 1.6-1.8, it is visibly dimmer than magnitude 1 Aldebaran and roughly as bright as Bellatrix. The next brightest star just to the north of Betelgeuse. Keep an eye on this historic dimming event, observing hints and stars for magnitude estimation are given here. The waxing/full moon will make it more difficult to estimate Belegeuses brightness.
Evening sky looking west at 3:36 ACDST on Saturday, January 11.The penumbral lunar eclipse has just started.
This is a very poor eclipse, with The moon immersed in the Earth's outer shadow and only the faintest hint of darkening will be seen before the dawn. Western Australia has the best view if western Australians want to get up around 3 am for maximum eclipse.
Venus is prominent above the western horizon in the early evening sky. Venus is now readily seen up to 90 minutes after sunset.
Mercury is low in the evening twilight but will be difficult to see this month.
Jupiter is lost in the twilight glow but will enter the morning sky later this month.
Mars is visible in the morning twilight. It is in the head of the scorpion, Scorpius, this week. It is close to the stars Omega 1 and 2 Scorpii on the 9th and 10th.
Saturn is in conjunction with the Sun on the 14th and will not become visible until it enters the morning sky in February.
Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.
Star Map via Virtual sky. Use your mouse to scroll around and press 8 when your pointer is in the map to set to current time.
Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
The Full Moon is Saturday, January 11. Penumbral lunar eclipse morning January 11 The Moon is at perigee when it is closest to the Earth on January the 14th.
Similar views will be seen elsewhere in Australia 60 minutes after sunset, click to embiggen.
Mars is low above the horizon and is in the head of Scorpius the scorpion. It is close to the stars Omega 1 and 2 Scorpii on the 9th and 10th. The inset shows the telescopic view of Mars on the 10th (10mm eyepiece 6" reflector).
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Evening sky looking north-east at 22:17 ACDST on Saturday, January 11 (90 minutes after sunset). Similar views will be seen elsewhere in Australia at the equivalent local time. Orion is readily visible. Betelgeuse is the bright red star below the "saucepan" of Orion. Red Aldebaran is almost the same height above the horizon as red Betelgeuse, making brightness comparisons easy.Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion. It is a variable star, with small fluctuations in brightness not visible to the casual observer.
Betelgeuse has dimmed substantially and is now even dimmer than last week, reportedly between magnitude 1.6-1.8, it is visibly dimmer than magnitude 1 Aldebaran and roughly as bright as Bellatrix. The next brightest star just to the north of Betelgeuse. Keep an eye on this historic dimming event, observing hints and stars for magnitude estimation are given here. The waxing/full moon will make it more difficult to estimate Belegeuses brightness.
This is a very poor eclipse, with The moon immersed in the Earth's outer shadow and only the faintest hint of darkening will be seen before the dawn. Western Australia has the best view if western Australians want to get up around 3 am for maximum eclipse.
Mercury is low in the evening twilight but will be difficult to see this month.
Jupiter is lost in the twilight glow but will enter the morning sky later this month.
Mars is visible in the morning twilight. It is in the head of the scorpion, Scorpius, this week. It is close to the stars Omega 1 and 2 Scorpii on the 9th and 10th.
Saturn is in conjunction with the Sun on the 14th and will not become visible until it enters the morning sky in February.
Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.
Star Map via Virtual sky. Use your mouse to scroll around and press 8 when your pointer is in the map to set to current time.
Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
Labels: weekly sky
Tuesday, December 31, 2019
Betelgeuse continues its historic fade
Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion the Hunter. It has shot to prominence recently as it has dimmed to levels not seen for over 25 years. It is now obviously dimmer than magnitude 0.85 Aldebaran and roughly as bright as Bellatrix, the next brightest star just to the north of Betelgeuse (see chart below). While there is a lot of excitement as Betelgeuse is likely to go supernova "soon", soon is probably 100,000 years away, and the current dimming has other explanations (see below).
While familiar to almost all casual observers of the night sky as the bright red star that forms the shoulder of Orion the hunter, most people were unaware until recently that Betelgeuse is a variable star with a complex cycle of dimming and brightening. While the variations in brightness are small they may form the basis of stories by indigenous Australians who were keen observers of nature.
As I said, the variability of Betelgeuse is complex, with a dominant period of 420 days, superimposed on a long period of 5-6 years and a shorter-term variability of around 180 days. The latest Astronomers telegram suggests that the "he current faintness of Betelgeuse appears to arise from the coincidence of the star being near the minimum light of the ~5.9-yr light-cycle as well as near, the deeper than usual, minimum of the ~425-d period".
It is possible that Betelgeuse is close to its minimum, so further observations are needed over the coming days. Towards the end of the week, the waxing moon will make it more difficult to estimate Belegeuses brightness.
In order to avoid the Purkinje effect, where red stars seem to become brighter the longer you stare at them, you need to keep shifting your gaze around. Try bracketing the star with observations of stars brighter and dimmer. to get a good comparison. A more comprehensive guide to observing variable stars is here. Different observers will have slightly different estimates. My last estimate was Betelguese was a trace under 1.6 and Les Dalrymple had it a trace over. Try not to let your expectations bias what you are seeing.
Labels: Betelgeuse, unaided eye observation, variable star
The Sky This Week - Thursday January 2 to Thursday January 9
The First Quarter Moon is Friday, January 3. Earth is at perihelion on the 5th. Venus is prominent in the evening sky visible well after the of twilight. Mars is visible in the morning twilight and enters the head of Scorpius the Scorpion. The Red Giant star Betelgeuse in Orion is still dimming.
The First Quarter Moon is Friday, January 3. The Moon is at apogee when it is furthest from the Earth on January the 2nd. Earth is at perihelion, when it is closest to the Sun, on the 5th.
Sky at 21:38 ACDST on Saturday, January 4 (60 minutes after sunset)
looking west as seen from Adelaide.
Similar views will be seen elsewhere in Australia 60 minutes after sunset, click to embiggen.
Morning sky at 5:01 ACDST facing east as seen from Adelaide on Saturday, January 4, 60 minutes before sunrise.
Mars is low above the horizon and passes into the head of Scorpius the scorpion. It is close to the bright star Acrab on the 8th and 9th.
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Evening sky looking north-east at 22:18 ACDST on Saturday, January 4 (90 minutes after sunset). Similar views will be seen elsewhere in Australia at the equivalent local time. Orion is readily visible. Betelgeuse is the bright red star below the "saucepan" of Orion. Red Aldebaran is almost the same height above the horizon as red Betelgeuse, making brightness comparisons easy.
Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion. It is a variable star, with small fluctuations in brightness not visible to the casual observer.
Betelgeuse has dimmed substantially and is now even dimmer than last week, reportedly between magnitude 1.5-1.7, it is visibly dimmer than magnitude 1 Aldebaran and roughly as bright as Bellatrix The next brightest star just to the north of Betelgeuse. Keep an eye on this historic dimming event, observing hints and stars for magnitude estimation are given here. Towards the end of the week, the waxing moon will make it more difficult to estimate Belegeuses brightness.
Venus is prominent above the western horizon in the early evening sky. Venus is now readily seen up to 90 minutes after sunset.
Mercury is low in the evening twilight but will be difficult to see this month.
Jupiter is lost in the twilight glow but will enter the morning sky later this month.
Mars is visible in the morning twilight. It enters the head of the scorpion, Scorpius, this week.
Saturn is lost in the twilight.
Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.
Star Map via Virtual sky. Use your mouse to scroll around and press 8 when your pointer is in the map to set to current time.
Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
The First Quarter Moon is Friday, January 3. The Moon is at apogee when it is furthest from the Earth on January the 2nd. Earth is at perihelion, when it is closest to the Sun, on the 5th.
Sky at 21:38 ACDST on Saturday, January 4 (60 minutes after sunset)
looking west as seen from Adelaide.Similar views will be seen elsewhere in Australia 60 minutes after sunset, click to embiggen.
Mars is low above the horizon and passes into the head of Scorpius the scorpion. It is close to the bright star Acrab on the 8th and 9th.
Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise, click to embiggen).
Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion. It is a variable star, with small fluctuations in brightness not visible to the casual observer.
Betelgeuse has dimmed substantially and is now even dimmer than last week, reportedly between magnitude 1.5-1.7, it is visibly dimmer than magnitude 1 Aldebaran and roughly as bright as Bellatrix The next brightest star just to the north of Betelgeuse. Keep an eye on this historic dimming event, observing hints and stars for magnitude estimation are given here. Towards the end of the week, the waxing moon will make it more difficult to estimate Belegeuses brightness.
Mercury is low in the evening twilight but will be difficult to see this month.
Jupiter is lost in the twilight glow but will enter the morning sky later this month.
Mars is visible in the morning twilight. It enters the head of the scorpion, Scorpius, this week.
Saturn is lost in the twilight.
Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.
Star Map via Virtual sky. Use your mouse to scroll around and press 8 when your pointer is in the map to set to current time.
Cloud cover predictions can be found at SkippySky.
Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
Labels: weekly sky
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