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Wednesday, July 27, 2016

 

Astrophiz Podcast 4 is Out

Astrophiz Podcast 4 is 0ut. Interview: Professor Sarah Maddison - Dust and Protoplanetary Disks History & Theory of radio astronomy: Dr Nadeshzda Cherbakov from Tver tells us about Grote Reber. Dr Ian Musgrave tells us "What's up in the sky this week" - The News Roundup: Magdalena Ridge Optical Interferometry, WIMPS and Kepler Reborn.
https://soundcloud.com/astrophiz/astrophiz-podcast-4-dr-sarah-maddison-protoplanetary-disks-dr-nadeshzda-cherbakov-grote-reber

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Tuesday, July 26, 2016

 

Southern Delta Aquariid Meteor Shower 29-31 July, 2016


Evening sky looking east from Adelaide at 2 am local time on July 30th in South Australia. The cross marks the radiant  (the point where the meteors appear to originate from) of the Southern Delta Aquariids.  Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

The Southern Delta-Aquarids meteor shower runs from from 12 July to 23rd August, peaking on Wednesday July the 30th. The number of meteors you will see depends on how high the radiant is above the horizon, and how dark your sky is. This shower is fairly faint, with the highest rate of around a meteor every 4 minutes (more detail below).

The ZHR  for Southern Delta Aquariids is 16 meteors per hour. The figure ZHR is zenithal hourly rate. This is the number of meteors that a single observer would see per hour if the shower's "point of origin", or radiant, were at the zenith and the sky were dark enough for 6.5-magnitude stars to be visible to the naked eye.

In practise, you will never see this many meteors as the radiant will be some distance below the zenith. Also, unless you are out deep in the countryside, the darkness will be less than ideal. As well, moonlight will significantly reduce rates. How many are you likely to see in reality? I discuss this further down, lets talk about when to see them first.

At 10 pm, face east, and look 4 hand spans and two finger widths above the horizon. One finger width right is the 4th magnitude star delta Aquarii. The radiant is just above this star. This meteor shower should be visible from 10.00 pm until dawn. The best rates will be at 2 am in the morning of the 30th. The radiant will be due north then, and close to the Zenith near the bright star Fomalhaut.

At 2 am people in the suburbs should see a meteor around once every 8 minutes, and in the country about once every 4 minutes at 2 am in the morning of the 30th.

When looking, be sure to let your eyes adjust for at least 5 minutes so your eyes can be properly adapted to the dark. Don't look directly at the radiant site, because the meteors will often start their "burn" some distance from it, but around a handspan up or to the side. Be patient, although you should see an average of a meteor every six to three minutes, a whole stretch of time can go by without a meteor, then a whole bunch turn up one after the other.

Make yourself comfortable, choose an observing site that has little to obstruct the eastern horizon, have a comfortable chair to sit in (a banana lounger is best), or blankets and pillows. Rug up against the cold.  A hot Thermos of something to drink and plenty of mosquito protection will complete your observing preparations. As well as meteors, keep an eye out for satellites (see Heavens Above for predictions from your site).

The sky will also be particularly beautiful, with the Milky Way stretching over the sky and constellation of Scorpius and Mars and Saturn gracing the western sky.

Use the NASA  meteor shower flux estimator for an estimate of what the shower will be like from your location. You need to choose 5 Southern Delta Aquariids and remember to set the date to 29-30 July or 30-31 July 2016.

Cloud cover predictions can be found at SkippySky.

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The Sky This Week - Thursday July 28 to Thursday August 4

The New Moon is Wednesday August 3. Venus and Mercury rise in the early evening sky. The Moon is close to Venus on Thursday August the 4th  Jupiter is visible in the early evening. Mars and Saturn are visible all evening long. Saturn is close to the red star Antares and forms a triangle with Mars. The Southern Delta Aquariid meteor shower peaks the morning of 30 July.

The New Moon is Wednesday August 3.

Evening sky on Thursday August 4 looking west at 45 minutes after sunset. Jupiter is above Venus and Mercury.  Venus and the crescent Moon are close  star Regulus. Similar views will be seen throughout Australia at the equivalent local time. (click to embiggen).

Jupiter was at opposition on the March 8th, when it was biggest and brightest as seen from Earth. Jupiter will be an excellent telescopic target but s rapidly coming too close to the horizon.

Jupiter is in the north-western evening sky as the sun sets, and is  good for telescopic observation from around 18:00 on until around 8:30 pm when it will be a little too close to the horizon. Jupiter's Moons will be an still be excellent sight.

Venus and Mercury continue to rise above the twilight glow this week, you will need a clear, unobstructed horizon to see them effectively at the beginning of the week, but by the end of the week Mercury will be sufficiently high in the dusk sky to see clearly. A little after half an hour after sunset, Venus, Mercury, the bright star Regulus and Jupiter make a nice line-up in the dusk sky.

Mercury comes closer to the bright star Regulus in the dusk and is closest on the 30th and 31st, Then Venus approaches and on Thurday 4 August Venus, Regulus and the crescent Moon are close in the dusk.

Evening sky on Saturday July 30 looking west as seen from Adelaide at 22:00 ACST. Mars, Saturn and Antares form a triangle. The inset shows telescopic views of Mars and Saturn. Similar views will be seen elsewhere in Australia at the equivalent local time. (click to embiggen).

Mars is high in the evening skies near the head of the Scorpion in Libra.

Mars continues to head back towards the head of the Scorpion this week. Mars forms a line with the star Dschubba in the head of the Scorpion and Antares.  As well Mars forms a triangle with Saturn and the red star Antares. Mars was at opposition on May 22,  and is visibly dimming, but is still a decent telescope object. It is visible all evening long. In even small telescopes Mars will be a visible disk, and you should see its markings. Mars comes visibly closer to Dschubba this week.

 Saturn was at opposition on the 3rd of June. However, Saturn's change in size and brightness is nowhere near as spectacular as Mars's, and Saturn will be a reasonable telescopic object for many weeks. Saturn is reasonably high in the evening sky and is readily visible below Scorpius. Saturn forms a triangle with Mars and the red star Antares. It is now high enough for good telescopic observation in the evening. In even small telescopes its distinctive rings are obvious.

Evening sky looking north from Adelaide at 2 am local time in South Australia. The starburst marks the radiant  (the point where the meteors appear to originate from) of the Southern Delta Aquariids. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

The Southern Delta-Aquarids meteor shower runs from from 12 July to 23rd August, peaking on the morning of Saturday July the 30th. The number of meteors you will see depends on how high the radiant is above the horizon, and how dark your sky is. This shower is fairly faint, with the highest rate of around a meteor every 4 minutes (more detail here).


There are lots of interesting things in the sky to view with a telescope. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

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Friday, July 22, 2016

 

Astrophiz Podcast 3 is Out

The Astrophiz podcast is out, Interview: Dave Hunter - Magnetometers and interpreting heliophysical satellite data. History & Theory of radio astronomy: Dr Nadeshda Cherbakov tells us about Karl Jansky. ANNNDD someone you might recognize talking about what is up in the sky this week.
https://soundcloud.com/astrophiz/astrophiz-podcast-3-heliophysics-karl-jansky

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Thursday, July 21, 2016

 

See the ISS buzz Jupiter and Mars AGAIN (22-23 July, 2016)

The ISS passes between Mars, Saturn and Antares, as seen from Adelaide on the evening of  Friday 22 July at 18:03 ACST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.The ISS passes near Antares and Saturn, as seen from Alice Springs on the on the evening of  Saturday 23 July at 18:46 ACST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.The ISS passes just below Jupiter, as seen from Sydney on the evening of  Friday 2 July at 18:33 AEST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.
All sky chart showing local  times from Heavens Above for Friday 22 July for Adelaide.All sky chart showing local  times from Heavens Above for Saturday 23 July for Alice Springs.All sky chart showing local times from Heavens Above for Friday 22 July for Sydney.

On July 22 and 23 there is series of bright passes of the International Space Station occurring in the early evening. In some places in Australia the ISS will pass close to Mars and Antaresat varying times, others close to Jupiter and in still others there are close passes to bright stars such as the pointers, sometimes close passes to all of the above and in a few places the ISS might even pass over Jupiter or Antares.

Friday evening (22 July) sees the  ISS pass close to Antares and Saturn as seen from Perth and Adelaide. Sydney, Alice Springs, Brisbane and Melbourne all see close passes to Jupiter, with Sydney almost seeing the ISS pass in front of it (regions nearby may see the ISS pass over Jupiter).

Saturday evening (23rd) Sees the ISS pass cose to Antareas and Saturn from Alcie SPrings (with the ISS almost passing over Antares) and Brisbane, With Adelaide, Sydney and Perth seeing reasonably close passes to Jupiter.

On both dates there are also closish passes to various other right stars (like the pointers and Arcturus).

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 Jupiter and missing it completely.
 
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. 

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Tuesday, July 19, 2016

 

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

The Last Quarter Moon is Wednesday July 27. Venus and Mercury rise in the early evening sky. Jupiter is visible in the early evening. Mars and Saturn are visible all evening long. Saturn is close to the red star Antares and forms a triangle with Mars. Comet C/2013 X1 PanSTARRS may be visible in strong binoculars in the evening sky.

The Last Quarter Moon is Wednesday July 27. The Moon is at perigee, when it is closest to the Earth, on the 27th.

Evening sky on Saturday July 23 looking west at 30 minutes after sunset. Jupiter is above Venus and Mercury, forming a line with the star Regulus. Similar views will be seen throughout Australia at the equivalent local time. (click to embiggen).

Jupiter was at opposition on the March 8th, when it was biggest and brightest as seen from Earth. Jupiter will be an excellent telescopic target but s rapidly coming too close to the horizon.

Jupiter is in the north-western evening sky as the sun sets, and is  good for telescopic observation from around 18:00 on until around 9:00 pm when it will be a little too close to the horizon. Jupiter's Moons will be an still be excellent sight.

Venus and Mercury continue to rise above the twilight glow this week, you will need a clear, unobstructed horizon to see them effectively at the beginning of the week, but by the end of the week Mercury will be sufficiently high in the dusk sky to see clearly. A little after half an hour after sunset, Venus, Mercury, the bright star Regulus and Jupiter make a nice line-up in the dusk sky.

Evening sky on Saturday July 23 looking west as seen from Adelaide at 22:00 ACST. Mars, Saturn and Antares form a triangle. The inset shows telescopic views of Mars and Saturn. Similar views will be seen elsewhere in Australia at the equivalent local time. (click to embiggen).

Mars is high in the evening skies near the head of the Scorpion in Libra.

Mars continues to head back towards the head of the Scorpion this week. Mars forms a line with the star Dschubba in the head of the Scorpion and Antares.  As well Mars forms a triangle with Saturn and the red star Antares. Mars was at opposition on May 22,  and is visibly dimming, but is still a decent telescope object. It is visible all evening long. In even small telescopes Mars will be a visible disk, and you should see its markings.

 Saturn was at opposition on the 3rd of June. However, Saturn's change in size and brightness is nowhere near as spectacular as Mars's, and Saturn will be a reasonable telescopic object for many weeks. Saturn is reasonably high in the evening sky and is readily visible below Scorpius. Saturn forms a triangle with Mars and the red star Antares. It is now high enough for good telescopic observation in the evening. In even small telescopes its distinctive rings are obvious.

Comet C/2013 X1 (PANSTARRS) rises  around 4:00 pm local time, and is clear the of  horizon murk from around 7:30 pm.  It is currently around magnitude 7.5, by the end of the week the waning Moon will rise sufficiently late that there is good chance of seeing the comet before Moon rise in good binoculars.  The comet will be close Centaurus for much of this week. Detailed maps and guides are here.

There are lots of interesting things in the sky to view with a telescope. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

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Monday, July 18, 2016

 

Venus (and Mercury) Returns to the Evening Sky. (17 July 2016)

Venus and Mercury above the horizon in the twilight glow at 18:06 ACST on Sunday 17 July. The inset shows Mercury and Venus at full resolution. Imaged with my Canon IXUS at 400 ASA 0.4" exposure and 3x Zoom. Click to emibggen to be able to see Mercury better.

Venus and Mercury have returned to the evening sky. Last Sunday (17 July) the pair were very close together, around a lunar diameter apart.

Unfortunately they were also very low to the horizon. However, 10 minutes after sunset I could easily see Venus , but not Mercury. By half an hour after sunset when the pair were a little over 3 finger-widths above the horizon (which in my case was the ocean, lucky me).

I could just see Mercury with averted vision, in another 10 minutes Mercury was reasonably visible but still a little bit prone to disappear if you looked right at it. I took  the picture shortly after this, then hied it back home as the cold and some amazing cold-resistant mosquitoes were getting to me.

Mercury will now pull away from Venus, heading towards Regulus and Jupiter, becoming more visible as the month wears on, and heading for a spectacular conjunction with Jupiter and Venus in late August. .

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Tuesday, July 12, 2016

 

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

The Full Moon is Wednesday July 20. Venus and Mercury return to the evening sky. Jupiter is visible in the early evening. Mars and Saturn are visible all night long. Saturn is close to the red star Antares and forms a triangle with Mars. The Moon is close to Mars and Saturn on the 19th. Comet C/2013 X1 PanSTARRS may be visible in strong binoculars in the evening sky.

The Full Moon is Wednesday July 20.

Evening sky on Saturday July 9 looking west at 30 minutes after sunset. Jupiter is above the close pair of Venus and Mercury. Similar views will be seen throughout Australia at the equivalent local time. (click to embiggen).

Jupiter was at opposition on the March 8th, when it was biggest and brightest as seen from Earth. Jupiter will be an excellent telescopic target but s rapidly coming too close to the horizon.

Jupiter is in the north-western evening sky as the sun sets, and is  good for telescopic observation from around 18:00 on until around 9:30 pm when it will be a little too close to the horizon. Jupiter's Moons will be an excellent sight all evening.


Venus and Mercury emerge from the twilight glow this week, although they will be difficult to see until late in the week, and even then you will need a clear, unobstructed horizon, like the ocean, to see them effectively. On Sunday 17 July Venus and Mercury are very close together, but are just four finger-widths above the horizon half an hour after sunset, so this will be a challenging observation. You may need binoculars to see Mercury.

Evening sky on Friday July 15 looking west as seen from Adelaide at 22:00 ACST. Mars, Saturn and Antares form a triangle, and the waning Moon makes a kite shape with them. The inset shows telescopic views of Mars and Saturn. Similar views will be seen elsewhere in Australia at the equivalent local time. (click to embiggen).

Mars is high in the evening skies near the head of the Scorpion in Libra.

Mars continues to head back towards the head of the Scorpion this week. Mars forms a line with the star Dschubba in the head of the Scorpion and Anatres.  As well Mars forms a triangle with Saturn and the red star Antares. Mars was at opposition on May 22, is visibly dimming, but is still a decent telescope object. It is visible all night long. In even small telescopes Mars will be a visible disk, and you should see its markings.

 Saturn was at opposition on the 3rd of June. However, Saturn's change in size and brightness is nowhere near as spectacular as Mars's, and Saturn will be a reasonable telescopic object for many weeks. Saturn is reasonably high in the evening sky and is readily visible below Scorpius. Saturn forms a triangle with Mars and the red star Antares. It is now high enough for good telescopic observation in the evening. In even small telescopes its distinctive rings are obvious.

The waxing Moon is close to Mars on the 14th and 15th, and Saturn of the 15th and 16th. The best display is on the 15th when the Moon, Mars, Saturn and Antares form a kite pattern in the sky.

Comet C/2013 X1 (PANSTARRS) rises  around 4:00 pm local time, and is clear the of  horizon murk from around 7:30 pm.  It is currently around magnitude 7.2, however, the waxing Moon is very close to the comet this week, making it very difficult to see even in a telescope.  The comet will be close Centaurus for much of this week. Detailed maps and guides are here.

There are lots of interesting things in the sky to view with a telescope. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

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