Astroblog

Monday, January 18, 2021

Thursday January 21 to Thursday January 28

The First Quarter Moon is Thursday January 21, this is an apogee First Quarter Moon. The bright planet Venus is low in the twilight morning skies. Mercury is low in the twilight skies. Dimming but still bright Mars now dominates the evening skies. On the 21st Mars is near the First Quarter moon, with Uranus in between.

The First Quarter Moon is Thursday January 21, this is an apogee First Quarter Moon, where the moon is furthest from the Earth.It will be interesting to compare this last quarter Moon with the Perigee First quarter Moon of November 19 and December 19.

Evening sky at 20:58 ACDST (30 minutes after sunset) on Saturday, January 23 facing west as seen from Adelaide. Mercury is low in the twilight above the horizon.

You will need a level, unobstructed horizon to see Mercury.

Similar views will be seen elsewhere in Australia at the equivalent local time (30 minutes after sunset), click to embiggen.

Whole sky at 22:08 ACDST (90 minutes after sunset), on Saturday, January 23 as seen from
Adelaide.

Similar views will be seen elsewhere at the equivalent local time (90 minutes after sunset). click to embiggen.

Evening sky at 22:10 ACDST (90 minutes after sunset) on Thursday, January 21 facing north as seen from Adelaide. Mars is the brightest object above the north-western horizon and is just below the apogee First Quarter moon. Uranus is between the pair, in binoculars, Uranus is the brightest object aide from Mars and the Moon in the binocular field. The inset shows the approximate binocular field of view for 10x50 binoculars.

Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes after sunset), click to embiggen.

Morning sky on Saturday, January 23 showing the eastern sky as seen from Adelaide at 5:58 am ACDST (30 minutes before sunrise). Venus is getting lower to the horizon. You will need a level, unobstructed horizon to see this.

Similar views will be seen elsewhere in Australia at the equivalent local time (30 minutes before sunrise), click to embiggen.

Mercury is low in the twilight. You will need a level, unobstructed horizon like the ocean to see this.

Venus is still visible low above the horizon in the morning. You may need a level, unobstructed horizon to see Venus.

Mars is readily visible in the evening sky above the north-western horizon in the early evening. Mars is the brightest object above the north-western horizon and on the 21st is just below the apogee First Quarter moon with Uranus between the pair.

Jupiter is lost in the twilight.

Saturn is lost in the twilight.

Printable PDF maps of the Eastern sky at 10 pm AEST, Western sky at 10 pm AEST. 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 the 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

# posted by Ian Musgrave @ 9:34 pm 0 comments

Saturday, January 16, 2021

Mars close to Uranus (15-27 January, 2021)


Evening sky at 22:14 ACDST (90 minutes after sunset) on Saturday, January 16 facing north as seen from Adelaide. Mars is the brightest object above the north-western horizon. Uranus is within a binocular field of Mars. Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes after sunset), click to embiggen.	Evening sky at 22:11 ACDST (90 minutes after sunset) on Tuesday, January 19 facing north as seen from Adelaide. Mars is the brightest object aside from the Moon above the north-western horizon. Uranus is just above Mars, Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes after sunset), click to embiggen.	<- td="">Evening sky at 22:10 ACDST (90 minutes after sunset) on Thursday, January 21 facing north as seen from Adelaide. Mars is the brightest object above the north-western horizon and is just below the apogee First Quarter moon. Uranus is between the pair, in binoculars, Uranus is the brightest object aide from Mars and the Moon in the binocular field. Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes after sunset), click to embiggen.

Approximate binocular view of Mars and Uranus as seen with 10x50 binoculars on on Saturday, January 16, click to embiggen.	Approximate binocular view of Mars and Uranus as seen with 10x50 binoculars on on Tuesday, January 19, click to embiggen.	Approximate binocular view of apogee First Quarter Moon, Mars and Uranus as seen with 10x50 binoculars on on Thursday, January 21, click to embiggen.

From now until roughly January 27 will be a good time to view Uranus. Although Uranus is bright enough to be (just) visible to the naked eye at magnitude 5.7, finding it can be quite difficult. Over the next few days we have a very bright signpost, Mars, to guide us. Between now and Wednesday 27 January Mars will be within binocular distance of Uranus. On the 21st, Uranus will be between Mars and the Moon, and within a wide field telescope objective field of view from Mars. With a telescope you should see Uranus as a tiny disk.

During this time Uranus is the brightest object aside from the star 19 Arietis (which is approximately as bright as Uranus) in the constellation of Aires, the Ram) and of course the Moon, within binocular range of Mars, but Uranus is easily distinguished as it is above Mars.

Binocular Spotter map suitable for printing (click it to embiggen and print) shows the nights Mars is within binocular range of Uranus (the large circle is the field of view of 10x50 binoculars the small the field of view of a 30mm telescope lens). Use the chart with a red light (or a torch with red cellophane over the end) so as not to interrupt your night vision.

The 21st is also the night of the apogee First Quarter moon, so you might like to try your hand at imaging Mars and Uranus.

Labels: binocular, Mars, Moon, Uranus

# posted by Ian Musgrave @ 12:15 am 0 comments

Wednesday, January 13, 2021

2021: From "Super" Moon to "Mini" Moon and back, a year of full Moons


Full Moon January 29, 0:500 AEST	Full Moon February 27 18:00. Minimum libration -30h	Full Moon March 29 05:00 AEST, Perigee +35h March 10.

Full Moon April 27 14:00, perigee April 28 + 11h	Full Moon May 26 21:00, perigee May 26 -9h Total Lunar Eclipse. 21:10	Full Moon June 25 05:00, perigee June 23 -24h

Full Moon July 24 13:00.	Full Moon August 22 22:00. Maximum Libration +24 h	Full Moon September 21 10:00.

Full Moon October 21 01:00,	Full Moon November 19 19:00, apogee +41h. Twilight Partial Lunar eclipse	Full Moon December 19 15:00 Moon at apogee 18th -26h

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 (AEST) they are full (unless they are below the horizon, in which case 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 27 to November 19) 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 2021 we have two good Perigee Moon is a row (April 27, May 26). One of which is a total Lunar Eclipse Moon (May 26). 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" moons of November 19/December 19).

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.

Labels: apogee, Blue Moon, Moon, perigee, public outreach, unaided eye, Yearly Moons

# posted by Ian Musgrave @ 10:31 pm 0 comments

Tuesday, January 12, 2021

Apogee (mini) and Perigee (super) First Quarter Moons

This years apogee and perigee First Quarter Moons. Apogee FQ is on January 21st at 11 pm AEST (not 11am as on the diagram), and official First Quarter is at 7 am AEST, 13 hours apart. Perigee FQ is further apart, official first quarter is at 1 am on the August 16th, and Perigee on the August 17th at 7 pm, 1 day and 18 hours apart.

Because the Moons orbit is elliptical, there are times when it is furthest from the Earth (apogee) and closest to the Earth (perigee). At these time the Moon is different in size as seen from Earth, the difference is subtle to the unaided eye, but readily seen in binoculars or telescope.

Until recently most people didn't give perigee and apogee Moons a second thought, but after they were invoked in some pseudoscience waffle, they were co-opted by the astronomical community to get people more interested in the sky, with perigee Full Moons becoming "Super" Moons.

Of course, the "Super Moon" (and "mini" apogee moon) focuses on the really obvious full Moon, but the other moon phase can occur at perigee and apogee too. Of course you can't see either a perigee or apogee new Moon (unless there is a total Solar Eclipse or annular solar eclipse from an apogee New Moon) and no one want's to get up at Dark O'Clock to see a Last Quarter Perigee or apogee Moon. But first Quarter?

Ahh that's a different story.

Last quarter Moons are relatively high in the sky at sunset, so you don't have to wait a while for the moon to get high enough to dispel the Moon Illusion so you don't confuse the illusion with the Moon's true size. Also, unlike the full moon, where there are no shadows and everything is a bit bland (if beautiful).

But the First Quarter Moon is more dramatic, with the shadows of the terminator bringing out the walls of the craters and the mountain peaks. Of course this is not all visible to the unaided eye, but in binoculars or even a small telescope the view is beautiful and reveals the size difference between the apogee and perigee Moon more easily.

This year the First Quarter Perigee is a bit over a day and a half after First Quarter 16th and 17th August), but still not bad, and apogee and First Quarter is only 13 hours apart (upcoming at 21 January). Next year the pairing is March 10 apogee, November 1 perigee.

Anyway, try your hand at discerning the size difference between the upcoming apogee First Quarter Moon and the August perigee First Quarter Moon. Tips for photographing them are here.

Labels: apogee, Moon, perigee

# posted by Ian Musgrave @ 11:51 pm 0 comments

Monday, January 11, 2021

Thursday January 14 to Thursday January 21

The First Quarter Moon is Thursday January 21, this is an apogee First Quarter Moon. The bright planet Venus is low in the twilight morning skies. Jupiter Mercury and Saturn are very low in the twilight skies. The Moon is close to the trio on the 14th but this conjunction will be difficult to see. Dimming but still bright Mars now dominates the evening skies. On the 21st Mars is near the First Quarter moon, with Uranus in between.

Evening sky at 21:02 ACDST (30 minutes after sunset) on Thursday, January 14 facing west as seen from Adelaide. The pair of Jupiter and Saturn are very low above the western horizon in the twilight and are joined by Mercury and the thin crescent Moon.
You will need a level, unobstructed horizon like the ocean to see this.

Similar views will be seen elsewhere in Australia at the equivalent local time (30 minutes after sunset), click to embiggen.

Whole sky at 22:13 ACDST (90 minutes after sunset), on Saturday, January 16 as seen from
Adelaide.

Similar views will be seen elsewhere at the equivalent local time (90 minutes after sunset). click to embiggen.

Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes after sunset), click to embiggen.

Morning sky on Saturday, January 16 showing the eastern sky as seen from Adelaide at 5:50 am ACDST (30 minutes before sunrise). Venus is getting lower to the horizon. You will need a level, unobstructed horizon to see this.

Similar views will be seen elsewhere in Australia at the equivalent local time (30 minutes before sunrise), click to embiggen.

Mercury is low in the twilight. close to Jupiter and Saturn this week. On Thursday, January 14 they are joined by the thin crescent Moon. You will need a level, unobstructed horizon like the ocean to see this.

Venus is still visible low above the horizon in the morning. You may need a level, unobstructed horizon to see Venus.

Mars is readily visible in the evening sky above the north-western horizon in the early evening. Mars is the brightest object above the north-western horizon and on the 21st is just below the apogee First Quarter moon with Uranus between the pair.

Jupiter can be seen in very low in early evening twilight sky in the west. Jupiter is near Saturn and the pair are lowering in the twilight and become progressively harder to see. They are joined by Mercury mid week. On the 14th the trio are joined by the thin crescent Moon. You will need a level, unobstructed horizon like the ocean to see this.

Saturn too is (barely) visible low in early evening twilight sky in the west. after the 14th it will be lost in the twilight.

Labels: weekly sky

# posted by Ian Musgrave @ 11:27 pm 0 comments

Saturday, January 09, 2021

Southern Skywatch January 2021 edition is now out!

Morning sky on Tuesday, January 12 showing the eastern sky as seen from Adelaide at 5:46 am ACDST (30 minutes before sunrise). Venus is getting lower to the horizon and is less than a finger-width from the thin crescent Moon. You will need a level, unobstructed horizon to see this. Similar views will be seen elsewhere in Australia at the equivalent local time (30 minutes before sunrise), click to embiggen.

The January edition of Southern Skywatch is now up.

In January most of the planetary action is low in the twilight.

January 12; crescent Moon close to Venus.. January 10; Moon at perigee. January 14; The crescent Moon close to the pair of Jupiter and Mercury, low in the evening twilight sky. January 21; Mars and waxing Moon close, with Uranus in between Mars and the Moon. January 21; Moon at Apogee (Apogee "mini" First quarter Moon).

Mercury is difficult to see low in the evening twilight. It is close to the Moon on the 14th, with Jupiter below.

Venus is close to the crescent Moon on the 12th low in the morning twilight..

Mars is close to the Moon on the 21st, with Uranus in between

Jupiter is low in the evening twilight. On January 14 the crescent Moon is close to the pair of Jupiter and Mercury, low in the evening twilight sky. You will need a flat, unobstructed horizon like the ocean or desert to see this, and may require binoculars to see the planets clearly.

Saturn is lost to view early in the month.

January 10; Moon at perigee. January 21; Moon at Apogee (Apogee "mini" First quarter Moon).

Labels: southern skywatch

# posted by Ian Musgrave @ 12:23 pm 0 comments

Friday, January 08, 2021

Coming Events: A Year of Southern Astronomy for 2021

Venus, crescent Moon, Saturn and Jupiter on 7 December 2021 at 22:05 ACDST, (90 Minutes after Sunset) as seen from Adelaide. Most of Australia will enjoy similar views 90 Minutes after Sunset Click to embiggen.

The table below shows significant astronomical events that can be seen with the unaided eye or minimal equipment in 2021 in Australia (and to some degree elsewhere in the Southern Hemisphere, ocultations and eclipses are very region specific).

This year we get a good Total Lunar eclipse during a perigee "super" Full Moon and a partial lunar eclipse under very poor conditions. There is a good opposition of Jupiter and Saturn. Mars skims past the Pleiades and Beehive cluster. Venus too skims past the Beehive. There is also a good opposition of Vesta.

While we don't have a spectacular conjunction of Jupiter and Saturn this, we have some fantastic parings and lineups and good meteor showers.

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
2 January 2021	Earth at Perihelion
12 January 2021	Crescent Moon and Venus close low in the morning twilight
14 January 2021	Crescent Moon, Mercury and Jupiter close low in the evening twilight
21 January 2021	Mars and waxing Moon close
21 January 2021	Uranus between Mars and the waxing Moon
February
6-7 February 2021	Venus close to Saturn low in the twilight
11 February 2021	Venus close to Jupiter and the crescent moon low in the twilight
19 February 2021	Mars near first Quarter Moon
20-28 February 2021	Mercury between Jupiter and Saturn in the twilight
28 February 2021	Mars within binocular distance of the Pleiades cluster
March
1-9 March 2021	Mars within binocular distance of the Pleiades cluster, closest on the 2nd
4 March 2021	Asteroid Vesta at opposition, just visible to the unaided eye, best in binoculars
5 March 2021	Mercury very close to Jupiter below Saturn in the morning
10 March 2021	Saturn close to the crescent Moon in the morning
11 March 2021	Mercury close to Jupiter and the crescent Moon in the morning
19 March 2021	Mars near waxing Moon
20 March 2021	Earth at Equinox
April
7 April 2021	Saturn near to the waning Moon in the morning sky
8 April 2021	Jupiter near to the crescent Moon in the morning sky
11 April 2021	Mercury close to the crescent Moon in the morning twilight
17 April 2021	Mars close to the crescent Moon
27 April 2021	Mars on outskirts of open cluster M35 (binoculars best)
28 April 2021	Perigee Full Moon ("super" Moon), 1:00 am
May
4 May 2021	Saturn close to waning Moon in the morning sky
5 May 2021	Jupiter near to the waning Moon in the morning sky
6-7 May 2021	Eta Aquariid meteor shower
14 May 2021	Thin crescent Moon above Mercury in morning sky
26 May 2021	Total eclipse Perigee Full Moon ("super" Moon), 12:00 pm (eclipse from 8 pm)
29 May 2021	Mercury and Venus close low in the twilight (binoculars best)
June
1 June 2021	waning Moon near Jupiter
12 June 2021	Venus near thin crescent Moon low in the evening sky
14 June 2021	Waxing crescent Moon and Mars near in evening sky
21 June 2021	Earth at solstice
23-24 June 2021	Mars crosses beehive cluster (binoculars best)
27 June 2021	Waning Moon close to Saturn
28 June 2021	waning Moon near Jupiter
July
3 July 2021	Venus at the edge of the beehive cluster, best in binoculars
6 July 2021	Earth at aphelion
8 July 2021	Mercury close to the thin crescent Moon in the morning
12 July 2021	Crescent Moon, Venus and Mars close in the evening
13 July 2021	Venus and Mars very close in the evening sky
22 July 2021	Venus very close to bright star Regulus
24 July 2021	Saturn near Moon
26 July 2021	Jupiter near Moon
29-30 July 2021	Southern Delta Aquarids meteor shower
30 July 2021	Mars very close to Regulus
August
2 August 2021	Saturn at opposition
10 August 2021	Mars near thin crescent Moon
11 August 2021	Venus close to crescent Moon
18 August 2021	Variable star Mira predicted to peak in brightness
19 August 2021	Jupiter at opposition
17-21 August 2021	Mercury close to Mars, closest on the 19th
20 August 20	Saturn near Moon
22 August 2021	Jupiter near Moon
September
6 September 2021	Venus close to bright star Spica
9 September 2021	Mercury and crescent Moon close in the evening sky
10 September 2021	Crescent Moon and Venus nearby forming triangle with Spica
17 September 2021	Waxing Moon near Saturn
18 September 2021	Waxing Moon near Jupiter
23 September 2021	Earth at Equinox
21 September 2021	Mercury close to bright star Spica
24 September 2021	Venus close to moderately bright star alpha2 Librae, below Scorpius and above the pair of Mercury and Spica
October
1 October 2021	Mercury and bright star Spica still close
10 October 2021	Venus, the crescent Moon and the bright star Antares form a triangle
14 October 2021	Saturn and the waxing Moon close
15 October 2021	Jupiter and the waxing Moon close
17 October 2021	Venus and the bright star Antares at their closest
21-22 October 2021	Orionid meteor shower
23-24 October 2021	Venus close to globular cluster M19 (binocular or telescope)
November
4 November 2021	Thin crescent Moon close to Mercury low in the twilight
8 November 2021	Venus close to thin crescent Moon below the teapot of Sagittarius
8-24 November 2021	Venus crosses the teapot of Sagittarius
10-11 November 2021	Waxing Moon near Saturn
11-12 November 2021	Waxing Moon near Saturn
18 November 2021	Leonid Meteor Shower
19 November 2021	Partial Lunar eclipse, difficult with mid eclipse in the twilight
December
3 December 2021	Mars and thin crescent Moon close low in the morning twilight
7-10 December 2021	Three bright planets form a line in the evening with the thin crescent. moon joining them, Venus and Moon close on the 7th
8 December 2021	Saturn and crescent Moon close
10 December 2021	Jupiter and crescent Moon close
14 December 2021	Geminid Meteor shower in the morning (waxing Moon sets before best rates)
18 December 2021	Apogee Full Moon (12:00 pm)
21 December 2021	Earth is at Solstice
23-30 December 2021	four bight planets, Mercury, Venus, Saturn and Jupiter line up in the evening twilight, on the 29th Venus and Mercury are at their closest.
1 January 2022	Thin crescent Moon very close to Mars low in the morning sky. Occultation seen in south eastern and south central Australia