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Saturday, April 21, 2018

 

[Aurora Alert] Geomagnetic warning and Aurora Watch (21 April)

The SWS has issued a geomagnetic warning and aurora watch for 21 April (UT) due to ongoing solar wind streams from a coronal hole. This can be anytime the UT day on the 21st.  The SWS predicts active conditions with the possibility of outbreaks of minor storms. 

If these geomagnetic events occur and result in aurora they could be seen from Tasmania weather permitting. The Moon is waxing and will not interfere with aurora. Be patient, as the activity may rise and fall of the magnetic polarity of the wind may fluctuate significantly.




Current condition are not yet conductive to aurora.

This event is unlikely to be spectacular, but still worth a look as viewing conditions are good.

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". A double arc,  blobs, and curtains were seen in Septembers aurora  last despite the moonlight.

Here is the near-real time satellite view of the clouds http://satview.bom.gov.au/
Cloud cover predictions can be found at SkippySky.  

A new aurora camera is being installed at Campania, Tasmania. A live feed of the images from this camera is still not available.

SUBJ: SWS GEOMAGNETIC DISTURBANCE WARNING 18/08
ISSUED AT 0631UT/20 APRIL 2018
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

Earth is currently under the influence of a high speed stream
from a negative polarity equatorial coronal hole. Geomagnetic
activity at Quiet to Active levels is expected and at times may
reach up to Minor Storm levels if there are notable southward
Bz periods.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED
DUE TO CORONAL HOLE HIGH SPEED WIND STREAM
FROM 20-21 APRIL 2018
_____________________________________________________________

GEOMAGNETIC ACTIVITY FORECAST
20 Apr:  Quiet to Active
21 Apr:  Quiet to Active

_____________________________________________________________
SUBJ: SWS AURORA WATCH
ISSUED AT 0117 UT ON 21 Apr 2018 by Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE

The solar wind is currently under the influence of a high speed solar
wind stream from a recurrent coronal hole. Geomagnetic activity
reached storm levels on April 20 and is forecast to be at unsettled to
active levels on April 21, with possible isolated minor storm periods.
If significant geomagnetic activity occurs, there will be a chance of
visible auroras for southernmost Australian regions (e.g., Tasmania
and coastline of Victoria) during local nighttime hours. 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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Wednesday, April 18, 2018

 

Venus and the Crescent Moon, Wednesday 18 April.

Venus and the crescent Moon on Wednesday 18 April, looking west at 18:21 ACST. Canon IXUS, 3xzoom, 1 sec exposure ASA 400. Click to embiggen.Image taken with my mobile phone almost immediately after, no idea of the conditions. Resolution is less than the canon shot. Click to embiggen.

After cloud and rain wiping out the Moon-Venus conjunction on the 17th, conditions tonight were good enough that I got the closer pairing of Venus and the Moon. The clouds made Venus a bit hard to see, but the twiligh glow made the whole scene rather spectacular.

Tomorrow will have the Moon further away from Venus but close to Aldebaran, which should look nice as well.

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The 2018 Australian Lyrid Meteor Shower, Morning 23 April

The morning sky looking north as seen from Brisbane at 5:00 am AEST on April 23. The Lyrid radiant is marked with a starburst. It is quite close to the obvious bright star Vega low above the northern horizon.

Similar views will be seen elsewhere at an equivalent local time. The radiant will be higher in northern Australia, and lower in southern Australia (click to embiggen). 

The Lyrids, the debris of comet C/1861 G1 (Thatcher) are a weak but reliable shower that occurs every year between April 16- April 25, with the peak this year on April 23 Australian time.

That's  around 10 am 23 April in east coast Australia, the radiant doesn't rise until 1 am on the 23rd, so the best time to view the Lyrids in Australia is from 4 am on the 23rd. 

The predicted ZHR this year is 18 meteors per hour. the number of meteors you could expect to see if the radiant (the apparent position where the meteors originate) was at the highest point of the sky, under dark sky conditions. Under ideal conditions, you will see a meteor on average about once every three minutes. This can be as interesting as watching paint dry. Also, while that meteor every three minutes is the average, meteors are like buses, you wait for ages and then a whole bunch turn up. In Australia, the rate is much less.

Under real conditions the Lyrids radiant will not rise to the zenith from most places, and most places won't have really dark skies. The lower the radiant is, the thicker atmosphere will obscure the fainter meteors, and some of the meteors will start to "burn" below the horizon, so over all you will see fewer.

This is particularly true in Australia, where the radiant is very low to the northern horizon. In Australia the radiant rises about 1 am local time, but it is not really high enough for there to be any real chance of seeing meteors until around 4 am, when the radiant is between three hand-spans to four hand-spans above the horizon (see diagram above). The Moon has long set, so Moonlight is not a factor this year.

From Australia, at 4 am, under dark sky conditions, we will see between 4 meteors per hour (southern states) to 6-8 meteors per hour (Northern Territory and QLD).


 If you want to see what the rates will be like at your area, try the Meteor Flux Estimator. The illustration shows the output for dark sky sites in Brisbane.

Unfortunately, both Chrome and Firefox have changed their security settings to prevent plugins from running, and the flux estimator only runs under Internet Explorer now.

Choose 6 April Lyrids from the drop down meteor shower Menu, the date (make sure that you set the year to 2015, and your location, most people will have to put in their latitude and longitude (strangely, Adelaide, Brisbane, Darwin and Perth are listed in the drop down menu, but Sydney, Melbourne and Hobart are not) under "other" in the location box.



This will give you a chart of the numbers of meteors per hour you can expect at various times (see image to the left).

The Lyrids are pretty poor in Australia, but if you are patient you may see the occasional meteor shooting up from below the horizon.

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Tuesday, April 17, 2018

 

The Sky This Week - Thursday April 19 to Thursday April 26

The First Quarter Moon is Monday, April 23.  Venus is low in the twilight and is visited by the Moon on the 19th. Jupiter is now rising in the early evening skies. Mars and Saturn are now visible in the late evening skies. Mercury is prominent in the morning skies. The Lyrid meteor shower peaks on the morning of the 23rd, but is really only visible form Brisbane and places north.

The First Quarter Moon is Monday, April 23. The  Moon is at perigee, when it is closest to the Earth, on the 21st.


Evening twilight sky on Thursday April 19 looking west as seen from Adelaide at 18:14 ACST (30 minutes after sunset). Venus is just above the horizon in the twilight. The crescent Moon is above it close to the bright star Aldebaran.

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

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is visible to the unaided eye from 15 minutes after sunset, easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Evening sky on Saturday April 21 looking east  as seen from Adelaide at 23:00ACST. Jupiter is  high above the horizon. Saturn is close to the horizon and Mars is just rising.

The inset is a simulated telescopic view of Jupiter and its moons at 3:00 ACST on the 22nd, with Europa and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).


Morning sky on Saturday April 21 looking north as seen from Adelaide at 5:19 ACST (90 minutes before sunrise). Mars and Saturn are high above the northern horizon and good telescopic viewing. The inset is a simulated telescopic view of Saturn and the globular cluster M22.


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



Morning sky on Saturday April 21 looking east as seen from Adelaide at 5:45 ACST (60 minutes before sunrise). Mercury is the brightest object closest to the eastern horizon.











The morning sky looking north as seen from Brisbane at 5:00 am AEST on April 23. The Lyrid radiant is marked with a yellow cross. Similar views will be seen elsewhere at an equivalent local time. The radiant will be higher in northern Australia, and lower in southern Australia (click to embiggen).  
 
The predicted ZHR this year is 18 meteors per hour. This means that under ideal conditions, you will see a meteor on average about once every three minutes. This can be as interesting as watching paint dry. Also, while that meteor every three minutes is the average, meteors are like buses, you wait for ages and then a whole bunch turn up.  But alos, that is under ideal conditions. In Australia, where the radiant is very low above the horizon, you are likely to see a meteor once every 10 minutes from the latitudes of Brisbane, far fewer to the south of this, with the best rates seen from Cairns and Darwin.

Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now over a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset and easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon. On the 19th the thin crescent Moon is near Venus.

Mercury has returned to the morning sky, and now is in an excellent position for observation. Mercury is the brightest object closest to the eastern horizon.


Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is moving away from Saturn although the pair are still obvious together.   Mars is brightening ahead of opposition later this year.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces.

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.
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, April 10, 2018

 

The Sky This Week - Thursday April 12 to Thursday April 19

The New Moon is Monday, April 16.  Venus is low in the twilight and is visited by the Moon on the 19th. Jupiter is now rising in the early evening skies. Mars and Saturn are now visible in the late evening skies. Mercury returns to the morning skies.

The New Moon is Monday, April 16.

Evening twilight sky on Thursday April 19 looking west as seen from Adelaide at 18:14 ACST (30 minutes after sunset). Venus is just above the horizon in the twilight. The crescent Moon is above it close to the bright star Aldebaran.

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

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is now visible to the unaided eye from 15 minutes after sunset and easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Evening sky on Saturday April 14 looking east  as seen from Adelaide at 23:00ACST. Jupiter is  high above the horizon. Close to the horizon Saturn is just rising, and Mars will soon follow.

The inset is a simulated telescopic view of Jupiter and its moons at 1:30 ACST on the 15th, with Ganymede and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).



Morning sky on Saturday April 14 looking north as seen from Adelaide at 5:14 ACST (90 minutes before sunrise). Mars and Saturn are high above the northern horizon and good telescopic viewing.


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



Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now over a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset and easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Mercury has returned to the morning sky, but will be difficult to see until next week.

Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is moving away from Saturn although the pair are still obvious together.   Mars is brightening ahead of opposition later this year.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces. Saturn is at aphelion on the 17th and appears motionless against the background stars.

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.
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, April 03, 2018

 

The Sky This Week - Thursday April 5 to Thursday April 12

The Last Quarter Moon is Sunday, April 8.  Venus is low in the twilight. Jupiter is now rising in the early evening skies. The waning Moon visits Saturn and Mars on April the 7thrd. Mars, bright Jupiter and Saturn form a line together with the bright stars Antares and Spica in the morning skies. Mars and Saturn are now visible in the late evening skies.

The Last Quarter Moon is Sunday, April 8. The Moon is at apogee, when it is furthest from the Earth, on the 8th.

Evening twilight sky on Saturday April 7 looking west as seen from Adelaide at 18:27 ACST (30 minutes after sunset). Venus is just above the horizon in the twilight.

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

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is now visible to the unaided eye from 15 minutes after sunset and easy to see 30 minutes after sunset.

Evening sky on Saturday April 7 looking east  as seen from Adelaide at 23:59 ACST. Jupiter is  high above the horizon. Close to the horizon is the triangle of Saturn Mars and the Last Quarter Moon.

The inset is a simulated telescopic view of Jupiter and its moons at 23:00 ACST, with Ganymede and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).



Morning sky on Sunday April 8 looking north as seen from Adelaide at 5:09 ACST (90 minutes before sunrise). Mars, Saturn and the Last Quarter Moon form a triangle. The inset shows the binocular view of Mars, Saturn and the Moon. Because of the closeness of the bright Moon the faint deep-sky objects will be difficult to see.


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


Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now over a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset.

Mercury is lost to view.

Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is away from Saturn and the globular cluster M22.   Mars and Saturn and M22 start the week within binocular range of each other. On the evening of the 7th and the morning of the 8th the Last Quarter Moon is close to Saturn and Mars, forming a triangle. The proximity of the Moon makes viewing the fain deep sky objects difficult.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the  bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces. Mars and Saturn are within binocular range of each other. On the evening of the 7th and the morning of the 8th the Last Quarter Moon iis close to Saturn and Mars, forming a triangle. The proximity of the Moon makes viewing the fain deep sky objects difficult.

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.
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, March 31, 2018

 

Tiangong 1 Falls, will Australia see it?

UPDATE to the UPDATE to the UPDATE: Tiangong 1 came down at 00:16 UT, 10:16 AEST (close to the median predicted time), in the south pacific, somewhere NW of Tahiti.

UPDATE to the UPDATE: Tiangong 1 now predicted to re-enter today, April 2, between 8:46 am and 1:06 pm AEST, median 10:56 AEST, almost certainly not going to be visible from Australia. Probably Pacific Micronesia to tip of South America.

Forecast image Satview.
UPDATE: Tiangong 1 is still in orbit, Refined predictions are ESA 23:25 UTC on 1 April plus or minus seven hours (that is 9:25 ± 7h AEST on April 2). Dr. Marco Langenbrook predicts (Satevo data) 1 April 20:30 UT ± 7h (GMAT data) 1 April 23:08 UT ± 8h (AEST 9:08 ± 8h April 2). Aerospace corporation April 2nd, 02:00 UTC ± 7 hours (12:00 AEST ± 7h April 2). Satview has an unrealistically precise 02 April 04:43 UT (14:43 AEST). This means for Australia, our best chances for seeing re-entry is if the space station re-enters at 14:00 AEST, with the re-entry path along a line from Darwin to Sydney. If it re-enters at 16:00 AEST then the path lies along southern Victoria. Both re-entries are daylight re-entries. Check you local circumstances around these times using Heavens Above set for your location and choose the "all passes" button.

The Chinese Space Station Tiangong 1 is falling to Earth. The latest, predictions suggest that it will re-enter somewhere around April 1 (UT, Australia is 10 hours ahead of UT (east coast), 9.5 hours ahead (central) and 8 hours ahead (west coast)). Dr. Marco Langenbrook predicts that it will come down between 1.9 April +- 17h and 1.7 April +- 15 h with the latter more likely. This article explains why it is so hard to predict.

image source: ESA/ESOC

Where is still hard to say, part of the track goes over Southern Australia, and it is possible Southern Victoria and Tasmania could see the re-entry if it occurs in the early hours of April 1. Heavens above has a live feed of Tiangong 1's track. if you want to keep up with its possible visibility from your site.

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Southern Skywatch April 2018 edition is now out!

The northern morning sky on April 2, 90 minutes before sunrise showing Saturn and the Mars close, Inset shows Saturn, Mars, and M22 through a widefield telescopic eyepiece. (similar views will be seen Australia wide 90 minutes before sunrise,  click to embiggen).

The April edition of Southern Skywatch is now up.

This month still sees most of the planetary action move to the evening sky. Speedy Mercury returns to the morning sky but Venus and Jupiter become more prominent in the evening sky and Mars and Saturn enter the late evening sky.


Jupiter becomes more prominent the evening sky, and is closes to the Moon on the 3rd and 30th.

 Mars is closest to Saturn and M22 (spectacularly so to M22) on the 2nd.

Saturn is close to the globular cluster M22 this month.

UPDATE: never post early in the morning before catching a plane, fixed the wrong dates.

March April 3, 30; Moon close to Jupiter. March April 7; Mars, Saturn  and Moon close

 March April 8; Moon at Apogee.  March April 21 Moon at Perigee.

March April 14-15, Crescent Moon close to Mercury in the twilight.

March April 18, Crescent Moon above Venus

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Monday, March 26, 2018

 

The Sky This Week - Thursday March 29 to Thursday April 5

The Full Moon is Saturday, March 31, this is a Blue Moon, the second for the year.  Venus is low in the twilight. Jupiter is now rising in the late evening skies but is still best in the morning. The waning Moon visits Jupiter on April the 3rd. Mars, bright Jupiter and Saturn form a line together with the bright stars Antares and Spica in the morning skies. Mars is closest to Saturn and the globular cluster M22 on the 2nd.

The Full Moon is Saturday, March 31, this is a Blue Moon, the second for the year. Blue Moons (as defined as the second full Moon in a month), occur every 2 years, 8 months and 18 days. Having two blue Moons in a year occurs roughly 4-5 times a century. The next time there are two blue Moons in a year is 2037.

Evening twilight sky on Saturday March 31 looking west as seen from Adelaide at 19:37 ACDST (30 minutes after sunset). Venus is just above the horizon in the twilight.

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

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is now visible to the unaided eye from 15 minutes after sunset and easy to see 30 minutes after sunset.

Evening sky on Tuesday April 3 looking east  as seen from Adelaide at 23:00 ACST Jupiter is  above the horizon close to the waning Moon.

The inset is a simulated telescopic view of Jupiter and its moons at this time on the 4th, with Io and its shadow transiting the Face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).





Morning sky on Monday April 2 looking north as seen from Adelaide at 5:03 ACST (90 minutes before sunrise). Mars is at its closest to Saturn and the bright globular cluster M22. The inset shows the telescopic view of Mars, Saturn and M22 in wide-field objectives.


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


Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset.

Mercury is lost to view.

Jupiter  is rising well before midnight, but it is still best to view in the morning sky, where it is high above the northern horizon. There are some good Jovian Moon events this week. Jupiter is visited by the waning Moon on April the 3rd

 Mars is in Sagittarius the archer. Mars is moving towards Saturn at the beginning of the week.   Mars and Saturn (and the globular cluster M22) start the week within binocular range of each other. By the 2nd Mars is closest to both Saturn and M22. Mars and M22 are close enough (0.21 degrees) that they will fit into medium field telescope eyepieces fields of view. Mars and Saturn are a finger-width apart, so you will need a wide-field eyepiece for these two to fit. Scanning with binoculars around Mars and Saturn will be very rewarding now the Moon is out of the way.

Saturn climbs higher in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the  bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces. Mars and Saturn are within binocular range of each other at the start of this week this week and the pair are closest on the 2nd.

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.
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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