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Wednesday, March 20, 2019

 

The Sky This Week - Thursday March 21 to Thursday March 28

The the Full Moon is Thursday 21 March  and the Last Quarter Moon is Thursday, March 28. This Full Moon is also technically a perigee "Supermoon", but not as good as February's Perigee Moon. The Earth is at Autumnal Equinox on the 21st and Adelaide Henge will occur. Mars is visible low in the evening skies and is in binocular range of the Pleiades cluster by the end of the week.  Jupiter enters the evening skies and is close to the Moon on the 28th. The morning skies feature Saturn, bright Venus and Mercury.

The the Full Moon is Thursday 21 March  and the Last Quarter Moon is Thursday, March 28, the Moon is at Perigee, when it is closest to the Earth, on the 20th. The Earth is at Autumnal Equinox on the 21st. Day and night are of equal length and the Sun rises due East and Sets due west (Hence Adelaide Henge).


Morning  sky on Thursday, March 28 looking east as seen from Adelaide at 6:30 ACDST (60 minutes before sunrise). Jupiter (out of view in this images) is high in the morning sky above Saturn, Venus and Mercury. The last quarter Moon is between Jupiter and Saturn. The left upper insert inset shows the telescopic view of Venus at this time and the upper right that of Saturn.


 Similar views will be seen elsewhere in Australia at the equivalent local time (60 minutes before sunrise).

Morning  sky on Thursday, March 28 looking east as seen from Adelaide at 0:15 ACDST (15 minutes after midnight). Jupiter is low above the eastern horizon just above the . The last quarter Moon is between Jupiter and Saturn. The left upper insert inset shows the telescopic view of Jupiter at this time

Similar views will be seen elsewhere in Australia at the equivalent local time .
Evening sky on Thursday, March 28 as seen looking north-west from Adelaide at 20:41 ACDST (90 minutes after sunset). Mars is the brightest object above the western horizon.

The Pleiades and Hyades also grace the north-western sky. Mars comes closer to the Pleiades over the week and is within binocular distance on the 28th.

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


The Earth is at Autumnal Equinox on the 21st. The Sun will rise due east and will set due west and Adelaide Henge will occur. This means that around these dates the setting/rising sun will light up the east-west streets of the Adelaide CBD at sunrise/sunset around the date of equinox. See details here.

Venus is bright in the morning skies below Jupiter and Saturn.

Mercury  climbs out of the twilight and is visible below Venus by the end of the week.

Jupiter  Jupiter is now rising just before midnight in the evening sky, but is low to the horizon and not a good telescope target until the morning. Jupiter is close to the last quarter Moon on the 28th.

Mars moves from Aries to Taurus and is the brightest object in low in the western evening sky. Mars sets around 9:30pm. Mars comes closer to the beautiful Pleiades cluster over the week and is within binocular distance on the 28th.

Saturn is climbs higher in the morning sky. The Last quarter Moon is between Jupiter and Saturn on the 28th.

 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.

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/

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Tuesday, March 19, 2019

 

Adelaide Henge 2019

Rundle Mall looking westHindeley street looking west

The equinox is on the 21st, where the Sun rises due east and sets due west and day and night are equal length. Aside from the marking of the passing of summer to Autumn, it is also a chance to see "city henge", in this case Adelaide henge.

Unlike the famous Stonehenge, whose stones are aligned to catch the summer and winter solstices. City henges are found in cities with a regular grid of east-west streets, where the rising and setting sun can shine through these human-made canyons at various times of the year. The most famous is Manhattan henge, where the skyscrapers of New York provide dramatic chasms for the setting sun to illuminate.

Less well known but still dramatic is Melbourne Henge.  Where great views are to be had down Collins Street and Bourke street amongst others as the setting sun washes the streets in golden glow.

And the  phenomenon can be seen in Adelaide too. We lack the skyscraper canyons, but our CBD east-west streets can still be illuminated with a golden glow.

Did I say east-west? while our CBD streets are nominally east west, they are infcat slightly out of alignment with true east (the streets of Melbourne are even more out of true being angled at 250 degrees west, which is why Melbourne Henge for the setting sun is 7 February and 4 November, not on the days of the equinox).

As our street are closer to East-west (North terrace being 87 degrees east and 263 degrees west as measured by my trusty compass) Adelaide henge is closer to the equinox. Sadly our best time to observe the sun setting through the city has passed. This was on the 16th at 19:33, when the sun was setting at 263 degrees. However, the sun moves slowly from this ideal alignment and our streets are broad, so good sunsets almost aligned with the streets such as North terrace, Rundle Mall and Hindle  street should be available over the next few days.

In contrast, best theoretical sunrise is not until 28 March, when the sun is 87 degrees from East and rising at 7:25. However, to the east is the Adelaide hills, and by the time the sun rises above then it will have moved off the direct line. Ironically the best time for the sunrise to shine down the street is on the 21st, at 7:36, as the sun just clears the Adelaide hills.

Again, those are the best  times, but a few days either side of those it will still be good. So get up early or stay in the city for sunset, and you might see something wonderful.


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Monday, March 18, 2019

 

February 20 Perigee Moon, 2019

Perigee (super) Moon of 20 February 2019. 25 mm eyepiece with Sony Xperia mobile phone ASA 800 1/4000 sec exposure. 4" Newtonian. Scaled full frame image. Click to embiggen.Perigee (super) Moon of 20 February 2019 2019. 25 mm eyepiece with Sony Xepria mobile phone
2 x Zoom, ASA 400 1/4000 sec exposure. 4" Newtonian. Scaled full frame image. Click to embiggen.

Comparison of the 20 February perigee "super" Moon (bottom) with the apogee "Mini Moon" on the night of Total Lunar Eclipse of 28 July, 4:25 am. Sony Xepria 1/2000th sec exposure ASA 400. Note the clear difference in size between the two (same image scale and zoom factor) compared to the 21 January image.Comparison of the 21 January perigee "super" Moon (bottom) with the apogee "Mini Moon" on the night of Total Lunar Eclipse of 28 July, 4:25 am. Sony Xepria 1/2000th sec exposure ASA 400. Note the small but clear difference in size between the two (same image scale and zoom factor).

Finally go around to processing my shots of the perigee ("super") moon of 20 February, and compared them to the shots from the 21 January perigee Moon. There is a claer difference from the 28 July apogee Moon of 2018, but the difference between the two perigee Moons is more subtle but still visible when you align the carefully. Now to wait for the September 13 Apogee Moon.

Overlay of the Full Moons of 21/01/19 and 20/02/19
same scale, the difference is subtle but can be seen
(click to embiggen)

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Thursday, March 14, 2019

 

From "Super" Moon to "Mini" Moon and back, a year of full Moons for 2019

Full Moon January 21,
Max libration, Perigee +  14h
Full Moon February 19, Perigee -   6hFull Moon March 21, Perigee -1d 5h
Full Moon April 19,
Maximum Libration +10h
Full Moon May 19, Maximum Libration -24hFull Moon June 17,
Full Moon July 17,
Minimum Libration +9h
Full Moon August 15, Full Moon September 13, Apogee -  15h
Full Moon October 14,
Maximum Libration +14h
Full Moon November 12,Full Moon December 12,

 A year of full Moons showing the variation in size as the moons move from perigee to apogee. All the moons are shown at midnight on the day they are full, and although this is not the optimal time for size comparisons, you can clearly see the size difference over the year (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 2019 we have three Perigee Moon is a row (although the March one really only barely scrapes in as a perigee Moon). 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 September 13.

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.

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Monday, March 11, 2019

 

The Sky This Week - Thursday March 14 to Thursday March 21

The First Quarter Moon is Thursday, March 14 and the Full Moon Thursday 21 March. This Full Moon is also technically a perigee "Supermoon", but not as good as February's Perigee Moon. The Earth is at Autumnal Equinox on the 21st. Mars is visible low in the evening skies and is coming closer the the Pleiades cluster.  Jupiter is high in the morning skies above Saturn and bright Venus.

The First Quarter Moon is Thursday, March 14 and the Full Moon Thursday 21 March, The Moon is at Perigee, when it is closest to the Earth, on the 20th. The Earth is at Autumnal Equinox on the 21st. Day and night are of equal length and the Sun rises due East and Sets due west.

Morning  sky on Saturday, March 16 looking east as seen from Adelaide at 5:50 ACDST (90 minutes before sunrise). Jupiter is high in the morning sky above Venus and Saturn. The left upper insert inset shows the telescopic view of Venus at this time. the lower left insert shows the telescopic view of Jupiter at the same scale and the upper right that of Saturn.

Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes before sunrise).

Evening sky on Saturday, March 16 as seen looking north-west from Adelaide at 20:58 ACDST (90 minutes after sunset). Mars is the brightest object above the western horizon.

The Pleiades and Hyades also grace the north-western sky. Mars comes closer to the Pleiades over the week.

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



Venus is bright in the morning skies below Jupiter and Saturn.

Mercury  is lost in the twilight but will return to the morning sky later in the month.

Jupiter  climbs higher in the morning sky. Jupiter is now rising just before midnight in the evening sky, but is too low to see without a level, unobstructed horizon.

Mars is in Aries and is the brightest object in low in the western evening sky. Mars sets around 10:00pm. Mars will come closer to the beautiful Pleiades cluster over the week.

Saturn is climbs higher in the morning sky.

 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.

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/

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Wednesday, March 06, 2019

 

A Nice Series of Bright International Space Sation Passes (7- 15 March 2018)

The ISS passes close to the bright star Rigel, above Orion's Belt as seen from Sydney on the evening of Sunday 10 March at 20:40 AEDST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.The ISS passes near the bright star Canopus, as seen from Adelaide on the  evening of Saturday 9 March at 20:58 ACDST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.The ISS passes below the bright star Canopus, as seen from Perth on the  evening of Saturday 9 March at 20:02 AWST. Simulated in Stellarium (the ISS will actually be a bright dot), the inset shows the binocular view of the close pass.click to embiggen.
All sky chart showing local times from Heavens Above for Sunday 10 March for Sydney.All sky chart showing local  times from Heavens Above for Saturday 9 March for Adelaide.All sky chart showing local times from Heavens Above for Saturday 9 March for Perth.

Over the next few days there are a series of very bright ISS passes in the evening where the ISS passes close to Canopus (Adelaide 9th, Brisbane 8th, Melbourne 7th and 10th, Sydney 11th, Darwin 13th), the Southern Cross  (Adelaide 7th,10th, Brisbane 11th, Melbourne 8th, Sydney 8th and 9th), Mars (Adelaide 11th, (includes Moon)) and some other iconic stars and constellations (Orion, Sydney 10th, Darwin 15th).

The following tables are from data provided from Heavens Above.

Passes from Adelaide (ACDST)


Date Brightness Start Highest point End Pass type
(mag) Time Alt. Az. Time Alt. Az. Time Alt. Az.
06 Mar-1.721:52:1010°SW21:53:5126°SSW21:53:5126°SSWvisible
07 Mar-2.621:01:2410°SSW21:04:2429°SE21:04:5527°SEvisible
08 Mar-1.820:10:4810°SSW20:13:1318°SSE20:15:3610°ESEvisible
08 Mar-2.021:46:4210°WSW21:48:4832°W21:48:4832°Wvisible
09 Mar-3.920:55:3610°SW20:58:5978°SE21:00:0241°ENEvisible
10 Mar-3.020:04:4210°SSW20:07:5438°SE20:11:0410°ENEvisible
10 Mar-1.221:42:0110°W21:44:0716°NW21:44:0716°NWvisible
11 Mar-2.320:50:1610°WSW20:53:2033°NW20:55:3515°Nvisible
12 Mar-3.519:58:5910°SW20:02:2172°NW20:05:4010°NEvisible
13 Mar-0.820:46:1310°WNW20:47:2712°NW20:48:4110°NNWvisible

Passes from Brisbane (AEST)
06 Mar-3.420:45:4110°SW20:49:0255°SSE20:51:0720°ENEvisible
06 Mar-1.022:22:4710°W22:23:5116°W22:23:5116°Wvisible
07 Mar-2.721:31:2210°WSW21:34:3136°NW21:34:5535°NNWvisible
08 Mar-3.520:40:1210°WSW20:43:3467°NW20:46:0417°NEvisible
09 Mar-1.321:26:4010°W21:28:4516°NW21:30:0213°NNWvisible
10 Mar-1.920:34:5810°WSW20:37:5427°NW20:40:4710°NNEvisible
12 Mar-0.820:30:4810°WNW20:32:0012°NW20:33:1310°NNWvisible

Passes from Darwin (ACST)
12 Mar-1.520:38:4910°SSW20:39:5619°SSW20:39:5619°SSWvisible
13 Mar-2.319:48:2210°S19:51:0021°SE19:51:4120°ESEvisible
14 Mar-2.220:33:2210°WSW20:36:2131°NW20:36:2431°NWvisible
15 Mar-3.819:42:0010°SW19:45:1989°WNW19:48:3011°NEvisible


Passes from Melbourne (AEDST)
06 Mar-2.020:46:3310°SSW20:49:1521°SSE20:51:0714°ESEvisible
06 Mar-1.022:22:4410°WSW22:23:5119°WSW22:23:5119°WSWvisible
07 Mar-3.821:31:3810°SW21:34:5581°S21:34:5581°Svisible
08 Mar-3.220:40:4310°SW20:43:5943°SE20:46:0419°Evisible
08 Mar-0.822:17:5810°W22:18:4814°W22:18:4814°Wvisible
09 Mar-2.521:26:2110°WSW21:29:2634°NW21:30:0231°NNWvisible
10 Mar-3.520:35:0610°SW20:38:2869°NW20:41:2213°NEvisible
11 Mar-0.921:22:0410°W21:23:3613°NW21:25:0910°NNWvisible
12 Mar-1.620:29:5710°WSW20:32:4424°NW20:35:3010°Nvisible

Passes from Perth (AWST)
06 Mar-1.020:55:3710°SSW20:56:3517°SSW20:56:3517°SSWvisible
07 Mar-2.020:05:0210°SSW20:07:4021°SE20:07:4021°SEvisible
08 Mar-1.419:14:5110°S19:16:2813°SSE19:18:0610°ESEvisible
08 Mar-1.420:50:0110°SW20:51:3325°WSW20:51:3325°WSWvisible
09 Mar-3.619:59:0010°SW20:02:2056°SE20:02:4750°ESEvisible
10 Mar-2.519:08:1510°SSW19:11:1328°SE19:14:0710°Evisible
10 Mar-1.220:45:0710°W20:46:5318°WNW20:46:5318°WNWvisible
11 Mar-2.719:53:3110°WSW19:56:4342°NW19:58:2123°Nvisible
12 Mar-3.819:02:2010°SW19:05:4384°SE19:09:0210°NEvisible
13 Mar-0.919:49:0510°W19:50:5314°NW19:52:4010°NNWvisible
14 Mar-1.818:57:0110°WSW18:59:5728°NW19:02:5210°Nvisible


Passes from Sydney (AEDST)
06 Mar-1.820:48:3110°SSW20:51:0019°SSE20:51:0719°SEvisible
07 Mar-1.319:58:2010°S19:59:4512°SSE20:01:1010°SEvisible
07 Mar-1.521:33:2210°SW21:34:5525°SW21:34:5525°SWvisible
08 Mar-3.320:42:2810°SW20:45:4343°SE20:46:0441°ESEvisible
09 Mar-2.319:51:4610°SSW19:54:3524°SE19:57:1711°Evisible
09 Mar-1.421:28:1210°WSW21:30:0223°W21:30:0223°Wvisible
10 Mar-3.420:36:5110°SW20:40:1160°NW20:41:2235°NNEvisible
11 Mar-3.719:45:4810°SW19:49:0962°SE19:52:2810°NEvisible
12 Mar-1.320:31:5510°W20:34:2519°NW20:36:5310°Nvisible
13 Mar-2.519:40:1710°WSW19:43:2940°NW19:46:3810°NNEvisible
15 Mar-0.819:35:4810°W19:37:3514°NW19:39:2210°NNWvisible

Passes from Hobart (AEDST)
06 Mar-3.420:45:4110°SW20:49:0255°SSE20:51:0720°ENEvisible
06 Mar-1.022:22:4710°W22:23:5116°W22:23:5116°Wvisible
07 Mar-2.721:31:2210°WSW21:34:3136°NW21:34:5535°NNWvisible
08 Mar-3.520:40:1210°WSW20:43:3467°NW20:46:0417°NEvisible
09 Mar-1.321:26:4010°W21:28:4516°NW21:30:0213°NNWvisible
10 Mar-1.920:34:5810°WSW20:37:5427°NW20:40:4710°NNEvisible
12 Mar-0.820:30:4810°WNW20:32:0012°NW20:33:1310°NNWvisible


When and what you will see is VERY location dependent, so you need to use either Heavens Above or CalSky to get site specific predictions for your location, a small difference in location can mean the difference between the ISS passing over a star or missing it completely. As always, start looking several minutes before the pass is going to start to get yourself oriented and your eyes dark adapted. Be patient, there may be slight differences in the time of the ISS appearing due to orbit changes not picked up by the predictions. Use the most recent prediction for your site.

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Tuesday, March 05, 2019

 

The Sky This Week - Thursday March 7 to Thursday March 14

The New Moon is Thursday, March 7 and the First Quarter Moon is Thursday, March 14. Mars is visible low in the evening skies and is visited by the crescent Moon on the 11th.  Jupiter is high in the morning skies above Saturn and bright Venus. There will be a series of bright passes of the International Space Station visible around or during the weekend in the early evening.

The New Moon is Thursday, March 7 and the First Quarter Moon is Thursday, March 14.

Morning  sky on Saturday, March 9 looking east as seen from Adelaide at 5:39 ACDST (90 minutes before sunrise). Jupiter is high in the morning sky above the pair of Venus and Saturn. The left upper insert inset shows the telescopic view of Venus at this time. the lower left insert shows the telescopic view of Jupiter at the same scale and the upper right that of Saturn.

Similar views will be seen elsewhere in Australia at the equivalent local time (90 minutes before sunrise).

Evening sky on Monday, March 11 as seen looking north-west from Adelaide at 21:15 ACDST (90 minutes after sunset). Mars is the brightest object above the western horizon. The crescent Moon is close to Mars

The Pleiades and Hyades also grace the north-western sky.

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



 The beginning of the week is is  a good time to observe our wonderful southern sky with the Moon out of the way. Looking at the wonderful clusters and nebula of our southern skies with the unaided eye or binoculars will be a treat. The Moon interference is minimal during the weekend, so this is a good viewing time too.

Evening sky on Saturday, March 11 as seen looking South from Adelaide at 21:15 ACDST (90 minutes after sunset).



 The Milky way stretches from the Southern cross (Wilto the Eagle to the people of the Adelaide Plains) in the south to the distinctive constellation of Orion and beyond. The Milky ways' satellite dwarf galaxies, the Magellanic clouds, (between and below the bright stars Canopus and Achernar) are easily seen away from the city lights. The large Magellanic cloud is the smudge directly below Canopus and at its highest, making an excellent binocular target.

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

The approximate 10x50 binocular view of the area around the Large Magellanic Cloud on Saturday, March 11 as seen  at 21:15 ACDST (90 minutes after sunset).

. The Tarantula nebula cane be seen at the top of the LMC.

Similar views will be seen elsewhere in Australia at the equivalent local time. Click to embiggen.





The ISS passes close to  Canopus, as seen from Adelaide on the  evening of Saturday 9 March at 20:59 AEDST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.

From around the 8th-13 of March there are a series of bright ISS passes coming close to various bright stars which should be seen from most of Australia.  When and what you will see is VERY location dependent, so you need to use either Heavens Above or CalSky to get site specific predictions for your location, but there should be lots of good ISS viewing for most of Australia.

More details of the passes in this post.


Venus is bright in the morning skies below Jupiter and Saturn.

Mercury  is lost in the twilight but will return to the morning sky later in the month.

Jupiter  climbs higher in the morning sky.

Mars is in Pisces and is readily seen as the brightest object in the western evening sky. Mars sets around 10:30pm and is visited by the crescent Moon of the 11th.

Saturn is climbs higher in the morning sky heading away from Venus.

 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.

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/

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