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Monday, September 16, 2019

 

The Sky This Week - ThursdaySeptember 19 to Thursday September 26

The Last Quarter Moon is Sunday September  22.  Earth is at spring equinox on the 23rd. Jupiter is easily visible as the brightest object in the north-western evening skies. Saturn is near Jupiter, is high in the evening skies.Venus and Mercury climb higher in the evening twilight.

The Last Quarter Moon is Sunday September  22.  Earth is at spring equinox on the 23rd, at this time the sun rises due east and sets due west and day and night are equal length. Get ready for Adelaide and Melbourne Henge.

Sky at 19:35 ACST on Saturday, 21 September (90 minutes after sunset) looking west as seen from Adelaide. Jupiter is high above the western horizon. Saturn is high above the northern horizon.

The left upper insert shows the telescopic view of Jupiter at 19:35. The left lower inset shows the telescopic view of Saturn at the same time and scale

Similar views will be seen elsewhere in Australia 90 minutes after sunset, click to embiggen.


The western horizon at 18:36 ACST on Saturday, 21 September (30 minutes after sunset) as seen from Adelaide. Mercury and Venus are just above the horizon and you will need a flat, clear horizon such as the desert or ocean to see them.

You may also need binoculars to pick out Mercury, it may become clearer if you wait 5 -10 minutes more for the sky to darken.



Similar views will be seen elsewhere in Australia 90 minutes after sunset, click to embiggen. 



Earth is at spring equinox on the 23rd, at this time the sun rises due east and sets due west and day and night are equal length. Many Australian cities are oriented on an "east west" grid, so theoretically we should be able to see the sunset down these major east-west road with the city scape forming a henge like canyon. However, our street are only approximately east west, the Adelaide city CBD streets are aligned to 263 degrees west, so the "henge" effect won't be seen until 6 October. For Melbourne the streets are aligned 250 degrees west, and their henge, best seen from the steps of Parliament  of Spring Street, is on 3-4 November. This gives you a bit of time to prepare. Do the streets of your town align east west? why not find if you will have a "city Henge" effect.

Venus is low above the western horizon in the evening twilight. You will need a level clear horizon like the desert or ocean to see it.binoculars to see it

Mercury is low above the western horizon in the evening twilight. You may need binoculars to see it initially in the twilight glow.

Jupiter is now well past opposition. However, it is still well worth observing. Jupiter is easily visible as the brightest object in the north-western/western sky (aside from the Moon) and is located just below the distinctive constellation of Scorpius and the bright red star Antares. It is visible all evening long and is a good telescope target in the evening, being highest above the northern horizon around 5:30 pm local time.

Mars is lost in the twilight.

Saturn was at opposition on July 10th, when it was visible all night long. Saturn is to the east of Jupiter and just below the "handle" of the "teapot of Sagittarius. It is best for telescopic viewing from just around astronomical twilight local time until the early morning and is highest above the northern horizon when it is ideal for telescopic imaging, around 7:30 pm local time.

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 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/
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Saturday, September 14, 2019

 

Images of the September 13 perigee Moon


Perigee Full Moon February 19 left, apogee Moon September 13 rightoverlay of February perigee moon (top) and September apogee Moon (bottom)

After a foggy, foggy morning the evening sky cleared and I had a wonderful view of the Friday September 13 apogee (mini) Moon. I set up the telescope a bit after true apogee (which was 23:03 ACST) due to watching Aquaman with the family (a good bad movie). But I got some nice shots with my Xperia mobile phone mounted on my 4" unguided Newtonian scope.

In the images above I contrast this apogee Moon with the perigee full Moon of February 19. In the scope there was a very clear distinction, but I was unable to tell the difference visually, mostly because I couldn't remember what the February Moon looked like. Some people can. I have used an overlay as well to show the contrast. It might be a bit exaggerated by eyepiece distortion becuase the Moon was not exactly centred.

Predicted contrast of apogee, perigee moon simulated in stellarium at the same local time.

However, comparing it to the predicted contrast shows the effect of eyepiece distortion is relatively minor.

On the 19th at 21:50 (when my image was taken) the Moon was 33' 40.9" wide and 354,659 Km away. Last night at 23:14, when the image was taken, it was 29' 48.8" wide and  400,666.9 Km away.

The September full Moon will actually occur tonight, just off apogee, but it will still be smaller than the February perigee Moon. So go out toniht an have a look!

You can see previous apogee/perigee pairs here and here















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Thursday, September 12, 2019

 

Apogee (mini) Full Moon September 13-14, 2019

Full Moon September 14, Apogee -  15hFull Moon February 19, Perigee -   6h

The Moon is at apogee on midnight, Friday, September 13, making the September Full Moon a mini-Moon. The Moon is officially full on the 14th at 3pm, but the Moon does not rise until 5:11 pm, so it will be a little bigger than a proper apogee full Moon. It will nice to compare this with the 20 February perigee "super" Moon (telescopic simulation above, but you can see previous apogee/perigee pairs here and here.)

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Tuesday, September 10, 2019

 

The Sky This Week - ThursdaySeptember 12 to Thursday September 19

The Full Moon is Saturday September 14 (apogee or mini-Moon).  Jupiter is easily visible as the brightest object in the north-western evening skies. Saturn is near Jupiter, is high in the evening skies.Venus and Mercury (just) return to the evening twilight.

The Full Moon is Saturday September 14. The Moon is at apogee on Friday September 13, making this a mini-Moon.

Sky at 19:30 ACST on Saturday, 14 September (90 minutes after sunset) looking west as seen from Adelaide. Jupiter is high above the western horizon. Saturn is high above the northen horizon.

The left upper insert shows the telescopic view of Jupiter at 19:30. The left lower inset shows the telescopic view of Saturn at the same time and scale

Similar views will be seen elsewhere in Australia 90 minutes after sunset, click to embiggen.


The western horizon at 18:30 ACST on Sunday 15 September (30 minutes after sunset) as seen from Adelaide. Mercury and Venus are just above the horizon and you will need a flat, clear horizon such as the desert or ocean to see them. You will also need binoculars to pick out Mercury.





Similar views will be seen elsewhere in Australia 90 minutes after sunset, click to embiggen. 


Full Moon September 14, Apogee -  15hFull Moon February 19, Perigee -   6h

The Moon is at apogee on midnight, Friday September 13, making the September Full Moon a mini-Moon. The Moon is officially full on the 14th at 3pm, but the Moon does not rise until 5:11 pm, so it will be a litlle bigger than a proper apogee full Moon. It will nice to compare this with the the 20 February perigee "super" Moon (telescopic simulation above, but you can see previous apogee/perigee pairs here and here.)


Venus returns to the evening sky low above the western horizon.

Mercury returns to the evening sky low above the western horizon. You will need binoculars to see it initally in the twilight glow.

Jupiter is now well past opposition. However, it is still well worth observing. Jupiter is easily visible as the brightest object in the north-western/western sky (aside from the Moon) and is located just below the distinctive constellation of Scorpius and the bright red star Antares. It is visible all evening long and is a good telescope target in the evening, being highest above the northern horizon around 6:00 pm local time.

Mars is lost in the twilight.

Saturn was at opposition on July 10th, when it was visible all night long. Saturn is to the east of Jupiter and just below the "handle" of the "teapot of Sagittarius. It is best for telescopic viewing from just around astronomical twilight local time until the early morning and is highest above the northern horizon when it is ideal for telescopic imaging, around 8:00 pm local time.

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 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/
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Tuesday, September 03, 2019

 

Southern Skywatch September 2019 edition is now out!

The Moon at 00:50 am AEST in Cairns on Monday 9 September just before Saturn disappears. The inset shows the telescopic view as just before Saturn disappears behind the Moon (click to embiggen).

On the evening of 8 September to te morning of 9 September Saturn is occulted by the waxing Moon as seen from north of a line from Perth to Rockhampton.

Saturn will disappear behind the dark limb of the Moon at a reasonable height for telescopic observation. In southern Australia the Moon and Saturn will be very close and visible together in telescopic eyepieces. (click to embiggen).


The September edition of Southern Skywatch is now up.

Mercury returns to the morning sky in the middle of  this month. but is very difficult to see After the 15th it is lost in the twilight.

Venus is lost in the twilight.

 Mars is close to the crescent Moon on the 2nd, low in the twilight, after this it is lost to view

Jupiter was at opposition on June the 11th, when it was brightest and biggest as seen from Earth.  Jupiter is still excellent for telescopic viewing. Jupiter is close to waxing Moon on the 10th.

Saturn was at opposition on July the 10th. The waxing Moon close to Saturn on the 12th. and and eastern Australia sees an occultation of Saturn.

September 6; Moon close to Jupiter. September 8-9; waxing Moon close to Saturn. September 8-9, an occultation of Saturn. September 30 thin crescent Moon near Mercury and Venus.

September 13 Moon at Apogee (apogee Moon), September 28 Moon at perigee.

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Monday, September 02, 2019

 

The Sky This Week - ThursdaySeptember 5 to Thursday September 12

The First Quarter Moon is Friday September 6.  Jupiter is easily visible as the brightest object in the north-western evening skies. The Moon is close to Jupiter on the 6th. Saturn, near Jupiter, is high in the evening skies. Saturn is close to the Moon on the 8-9th and is occulted in north-western Australia.

The First Quarter Moon is Friday September 6.

Sky at 19:25 ACST (90 minutes after sunset) on Friday, 6 September looking west as seen from Adelaide. Jupiter is high above the western horizon. Saturn is to the east.

The left upper insert shows the telescopic view of Jupiter at 21:50. Europa will pass behind Jupiter then. The left lower inset shows the telescopic view of Saturn at the same time and scale

Similar views will be seen elsewhere in Australia 90 minutes after sunset, click to embiggen.


The Moon at 00:50 am AEST in Brisbane on Monday 9 September just before Saturn disappears. The left inset shows the telescopic view as  Saturn disappears behind the Moon (click to embiggen).

From the north-west of Australia Saturn is occulted by the Moon around midnight.  The rest of Australia sees the Moon and Saturn very close.

Timings and spotter charts can be found at my occultation site.



The whole sky at 19:24 ACST (90 minutes after sunset) on Saturday, September 7 as seen from Adelaide. The Southern Cross is beginning to leave the zenith. However, the galactic core (and the celestial emu) is at the zenith and there are numerous clusters and nebula high in the sky in the tail of the Scorpion and the lid of the teapot of Sagittarius  that will be a delight to explore while the Moon is out of the way. The binocular chart above will help you explore the area around the Southern Cross.

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

Venus is lost in the morning twilight and will return to the evening sky in mid-September.

Mercury is lost in the twilight and will return to the evening sky mid-September near Venus.

Jupiter is now well past opposition. However, it is still well worth observing. Jupiter is easily visible as the brightest object in the north-western/western sky (aside from the Moon) and is located just below the distinctive constellation of Scorpius and the bright red star Antares. It is visible all evening long and is a good telescope target in the evening, being highest above the northern horizon around 6:30 pm local time. The Moon is close to Jupiter on the 6th

Mars is lost in the twilight.

Saturn was at opposition on July 10th, when it was visible all night long. Saturn is to the east of Jupiter and just below the "handle" of the "teapot of Sagittarius. It is best for telescopic viewing from just around astronomical twilight local time until the early morning and is highest above the northern horizon when it is ideal for telescopic imaging, around 8:30 pm local time. Saturn is close to the Moon on the 8-9th and is occulted in north-western Australia.

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 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/

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Occultation of Saturn, Sunday-Monday, 8-9 September 2019.

The Moon at 00:02am ACST in Alice Springs on Monday 9 September just before Saturn disappears. The inset shows the telescopic view as just before Saturn disappears behind the Moon (click to embiggen).The Moon at 00:50 am AEST in Cairns on Monday 9 September just before Saturn disappears. The inset shows the telescopic view as just before Saturn disappears behind the Moon (click to embiggen). The Moon at 22:00pm AWST in Perth on Sunday 8 September just before Saturn disappears. The inset shows the telescopic view as just before Saturn disappears behind the Moon (click to embiggen).

On the late evening of Sunday 8 September to early morning 9 September Saturn is occulted by the waxing Moon as seen from northern Australia north of of a line from Perth to north of Rockhampton.

The Moon, above the western horizon, is a very obvious signpost for where to look. From most locations the occultation starts around midnight, with central and eastern locations occurring on the morning of the 9th, and western on the late evening of the 8th.

Saturn may be hard to spot visually against the glare of the Moon but is readily visible in telescopes and binoculars. In some locations titan is occulted as well (Alice Springs 00:09, Broome 22:32, Cairns, 00:53, Darwin 00:05, Perth 22:03, Townsville 00:57). Start watching about half an hour beforehand to get set up and familiar with the sky.

Saturn will disappear behind the dark limb of the Moon at a reasonable height for telescopic observation. Reappearance will be hard to see as you have to be looking just at the right moment.

The Moon at 00:21 am ACST in Adelaide (about 45 minutes after sunset) on Monday 9 September as Saturn is closest to the Moon. (click to embiggen).

In the rest of Australia the Moon and Saturn will be very close. In southern Australia the Moon and Saturn will be visible together in telescopic eyepieces. In Rockhampton Saturn will just miss the Moon.





Start watching about half an hour beforehand to get set up and familiar with the sky. Saturn will disappear behind the dark limb of the Moon at a reasonable height for telescopic observation.

Reappearance will be harder to see as you have to be looking just at the right moment.

PlaceDisappears Dark LimbReappears Bright Limb
Alice Springs ACST00:07 1:02
Brisbane AEST--
Broome AWST22:1623:38
Carins AEST00:521:44
Canberra AEST--
Darwin ACST00:0601:19
Hobart AEST--
Melbourne AEST- -
Perth AWST22:0123:02
Sydney AEST--
Rockhampton AEST--
Townsville AEST00:5501:38



Thursday, August 29, 2019

 

[Aurora Alert] Geomagnetic Disturbance Warning (31 August- 1 September 2019)

The SWS has issued an geomagnetic alert for warning for 31 August due to the arrival of a corotating interaction region and high-speed solar wind streams associated with the recurrent trans-equatorial coronal hole. Currently geomagnetic conditions are quiet, but may reach minor storm levels late on the evening of the 31st  or early morning on September the 1st. Aurora could be seen in Southern Australia under dark sky conditions. Tasmania sand Southern Victoria should see something if aurora occur.

The Moon is just past new will not interfere with seeing aurora. Be patient, as the activity may rise and fall of the magnetic polarity of the wind may fluctuate significantly.

Dark sky sites have the best chance of seeing anything, and always allow around 5 minutes for your eyes to become dark adapted.

As always look to the south for shifting red/green glows, beams have been reported consistently over the last few aurora, as well as bright proton arcs and "picket fences".

Here is the near-real time satellite view of the clouds http://satview.bom.gov.au/
Cloud cover predictions can be found at SkippySky.  
======================================================================
SUBJ: SWS GEOMAGNETIC DISTURBANCE WARNING 19/19
ISSUED AT 2354UT/28 AUGUST 2019
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

In the second half of UT day 31 August, global geomagnetic activity
may reach Active and Minor Storm levels due arrival of corotating
interaction region and high-speed solar wind streams associated
with the recurrent trans-equatorial coronal hole.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED
DUE TO CORONAL HOLE HIGH SPEED WIND STREAM
FOR 31 AUGUST 2019
_____________________________________________________________

GEOMAGNETIC ACTIVITY FORECAST
31 Aug:  Quiet to Minor Storm
====================================================================
SUBJ: SWS AURORA OUTLOOK
ISSUED AT 0139 UT ON 29 Aug 2019 by Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE

Effects of a coronal hole are expected to impact the Earth on 31
August and 1 September, possibly resulting in significant geomagnetic
activity and visible auroras during local nighttime hours from
Tasmania and Coastline of Victoria. Aurora alerts will follow if
significant geomagnetic activity actually occurs.

Visit the SWS Aurora webpage http://www.sws.bom.gov.au/Aurora for current
aurora viewing conditions.

Our Aurora forecasting tool, located at
http://www.sws.bom.gov.au/Aurora/3/1, may help to estimate regions
from where aurora would be visible.

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