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Tuesday, March 19, 2024

 

Thursday March 21 to Thursday March 28

The Full Moon is Monday March 25. There is a very disappointing penumbra eclipse at this time (low in the evening twilight). Jupiter is low in the north-western twilight sky and sets around half an hour after the sky is fully dark. Jupiter and Uranus are within binocular distance of each other by the end of the week. Venus is visible in the morning twilight below Mars. Saturn is close to Venus and is closest on the 22nd.

The Full Moon is Monday March 25. There is a very disappointing penumbral lunar eclipse at this time, where the outer part of earth’s shadow brushes against the Moon, resulting in a subtle darkening of the Moon. sadly, most of the eclipse takes place before the moon rises into the very early evening twilight, so will be nearly impossible to see. The Moon is at apogee, when it is furthest from Earth, on the 24th.

Evening sky on Saturday, March 23 as seen from Adelaide at 20:17 ACDST (60 minutes after sunset). Jupiter is low above the north-western horizon and coming closer to Uranus.  The inset is the telescopic view at this time.





    

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes after sunset).

Evening sky on Thursday, March 28 as seen from Adelaide at 20:06 ACDST (60 minutes after sunset). Jupiter is low above the north-western horizon and within binocular distance of Uranus.  The inset is the binocular view of the pair at this time.





    

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes after sunset).

Morning sky on Friday, March 22 as seen from Adelaide at 06:26 ACDST, (60 minutes before sunrise, click to embiggen). Venus is below Mars and is at its closest to Saturn. You may need binoculars and a low, level horizon to see the pair at their best. the inset in the binocular view of the pair.





 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).
 
Whole sky on Saturday, March 23 as seen from Adelaide at 20:47 ACDST, 90 minutes after sunset (click to embiggen). Jupiter is low in the north-west.


Orion is now in the north-west. Bright Sirius is high in  the north-western sky. Between the bright star Canopus and the Southern Cross are a wealth of binocular objects to discover. With the Moon full, the fainter clusters will be washed out.

 

   

 Elsewhere in Australia will see a similar view at the equivalent time (90 minutes after sunset).

 

 

Mercury is lost in the twilight.

Venus is in the morning twilight, it is sinking towards the horizon but will remain visible for all of March. Mars and Venus draw further apart. On the 22nd Venus is below Mars and at its closest to Saturn.After this Saturn Pulls away and heads towards Mars.

Mars is rising in the morning twilight and moving away from Venus. 

Jupiter is visible low in the early evening twilight sky. It is coming closer to Uranus and is within binocular distance of Uranus.

Saturn returns to the morning twilight. On the 22nd Venus is closest to Saturn.

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/





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Thursday, March 14, 2024

 

Follow-up to the Imaging Vesta Challenge, March 2024

Stack of 30x 1 second exposures at ISO 3200 with my canon IXUS "point and shoot" on 8 March. Click to embiggen.
Black and White printable map for locating Vesta at s asimilar scale to the images. Elnath and zeta Tau (Tianguan) are fairly obvious and Vesta is near 121 Tau. Click to embiggenPhotorealistic map for locating Vesta (and in conjunction with the printable map). Elnath and zeta Tau (Tianguan) are fairly obvious and Vesta is near 121 Tau. Click to embiggen.
Stack of 30x 1 second exposures at ISO 3200 with my canon IXUS "point and shoot" on 8 March. Click to embiggen.Labelled Stack of 30x 1 second exposures at ISO 3200 with my canon IXUS "point and shoot" on 8 March. Click to embiggen.
Stack of 10x 4 second exposures at ISO 3200 with my Samsung S24 on 8 March. Click to embiggen.Labelled stack of 10x 4 second expsures at ISO 3200 with my Samsung S24 on 8 March. Click to embiggen.

So how did my asteroid 4 Vesta imaging challenge go? Remember my original attempt didn't go too well, despite my confidence. 

I had a second opportunity on the 8th. The sky clarity was better, I could actually see Tianguan (zeta tau) and Elnath on the back of the camera/phone screen in test shots (there was a lot of groobling around on the ground setting up the shots  and several test exposures to get the right patch zoomed in. My Knees do not like me as I did this on the gravel bike path near the beach. 

But eventually I got Tianguan (zeta tau) and Elnath framed at a good zoom level (don't ask me what the Zoom is, the Canon IXUS just gives a zoom bar and the Samsung S24 give a zoom level but I forgot to record it. Both the IXUS and Samsung were on a tripod (I have a special adapter to pones for my tripod).

For the point and shoot IXUS I took 30 x 1 second frames at ISO 3200 (f/5.6), as the IXUS doesn't take exposures longer than 1 second (well it does, but defaults to ISO 50!). I traded noise for sensitivity. I also took a dark frame (exposure exactly the same as the main images but with the lens blocked to account for noise. The frames were then stacked in Deep Sky Stacker, the stacked output saved (a TIFF file), then exposure adjusted in The GIMP and the TIFF converted to JPG. 

Unlike last time 4 Vesta was clearly (if faintly visible). You should embiggen the images above to see Vesta clearly.

For the Samsung S24 I took 10 x 4 second frames at ISO 3200, f/3.4no dark frame though. The frames were then processed as for the IXUS (stacked in Deepsky Stacker, the stacked output saved (a TIFF file), then exposure adjusted in The GIMP and the TIFF converted to JPG). The result is much better than the single 10 second exposure.  

The Samsung S24 is cheating though, few cameras/phones have a 200 megapixel camera. They will be closer to the 20 megapixel IXUS. But the point is that even with an ordinary camera phone and stacking you can take effective astrophotos down to at least magnitude 8. This opens up a world of sky imaging you didn't think you could access with simple equipment. 

How did others go, Well Brendan got Vesta on the 9th,

Brenden stacked a sequence in Photoshop. 20 x 5 sec ISO 1600 f/5 42mm on Canon 1000D DSLR on tripod.

Vesta is seen faintly above121 tau and has clearly moved since my images on the 8th.

 If anyone else has images and wants to submit them, let me know. 
 



Single 10 second second exposure at ISO 3200 with my Samsung S24 on 3 March, Vesta is just visible. Labelled stack of 10x 4 second expsures at ISO 3200 with my Samsung S24 on 8 March. Click to embiggen.

In these images from 3 and 8 mrach you can clearly see the movement of Vesta.

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Wednesday, March 13, 2024

 

Thursday March 14 to Thursday March 21

The First Quarter Moon is Sunday March 17. The Earth is at Equinox on the 20th. Jupiter is low in the north-western twilight sky and sets around an hour after the sky is fully dark. On the 14th the crescent Moon is near Jupiter. Venus is visible in the morning twilight below Mars. Saturn makes an appearance low in the morning twilight by midweek, and is close to Venus from the 19th.

The First Quarter Moon is Sunday March 17. The Earth is at Equinox on the 20th when the day is equal in length to the night.

Evening sky on Thursday, March 14 as seen from Adelaide at 20:30 ACDST (60 minutes after sunset). Jupiter is low above the north-western horizon and near to the crescent Moon.  The inset is the telescopic view at this time.





    

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes after sunset).

Morning sky on Saturday, March 16 as seen from Adelaide at 06:21 ACDST, (60 minutes before sunrise, click to embiggen). Mars, Venus and Saturn form a line, you will need a level uncluttered horizon, and possibly binoculars, to see Saturn. The inset is the telescopic view at this time.




 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).
 
Morning sky on Thursday, March 21 as seen from Adelaide at 06:25 ACDST, (60 minutes before sunrise, click to embiggen). Venus is below Mars and close to Saturn.





 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).
 
Whole sky on Saturday, March 16 as seen from Adelaide at 21:08 ACDST, 90 minutes after sunset (click to embiggen). Jupiter is low in the north-west.


Orion is now in the north-west. Bright Sirius is high in  the north-western sky. Between the bright star Canopus and the Southern Cross are a wealth of binocular objects to discover. With the Moon waxing, this is still an excellent time to hunt the fainter clusters.

 

   

 Elsewhere in Australia will see a similar view at the equivalent time (90 minutes after sunset).

 

 

Mercury is lost in the twilight.

Venus is in the morning twilight, it is sinking towards the horizon but will remain visible for all of March. Mars and Venus draw further apart. On the 21st Venus is below Mars and close to Saturn.

Mars is rising in the morning twilight and moving away from Venus. 

Jupiter is visible low in the early evening twilight sky. On the 14th the crescent Moon is near Jupiter.

Saturn returns to the morning twilight. On the 21st Venus is close to Saturn.

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/





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Thursday, March 07, 2024

 

Imaging Vesta Challenge, March 2024

Black and White printable Black and White printable Northern horizon map for locating Vesta. Map is set at astronomical twilight,  21:12 ACDST, 90 minutes after sunset. Elnath and zeta Tau (Tianguan) are fairly obvious below Orion. Click  to embiggen and print.and print.
Black and White printable map for locating Vesta suitable for binoculars. Elnath and zeta Tau (Tianguan) are fairly obvious and Vesta is near 121 Tau. The circle is the approximate field of view of 10x50 binoculars. Click  to embiggen and print.
Photrealistic Northern horizon map for locating Vesta (and in conjunction with the printable map). The mMap is set at astronomical twilight,  21:12 ACDST, 90 minutes after sunset. Elnath and zeta Tau (Tianguan) are fairly obvious below Orion. Click  to embiggen .Photrealistic  map for locating Vesta suitable for binoculars (and in conjunction with the printable map). Elnath and zeta Tau (Tianguan) are fairly obvious and Vesta is near 121 Tau. Click  to embiggen.
Stack of 10x 1 second exposures at ISO 3200 with my canon IXUS "point and shoot" on 3 March, Vesta is not readily visible.
Single 10 second second exposure at ISO 3200 with my Samsung S24 on 3 March, Vesta is just visible.

So, for this months Astrophotography challenge I set "imaging the Asteroid 4 Vesta". Now vesta is magnitude 8 at the moment, a bit dim, but visible in binoculars and potentially image-able with fairly ordinary cameras using stacking, a powerful software technique where multiple images and be combinted to enhance dim objects.  

The biggest challenge is actually aiming your camera, even though the horns of the bull, Elnath and zeta Tau (Tianguan) are fairly obvious, they did not really show up well in the back of my canon IXUS not the mobile phone. So I had to do a bit of guess work in aiming and do a number of test shots to get Elnath and zeta Tau in view.

For the Canon IXUS "point and shoot" camera I took 10 x 1 second exposures at ISO 3200 and stacked them in Deep Sky Stacker, This wasa simple "drag and drop" procedure. I was limited to 1 second exposures because Canon messed up their long duration exposures (anything over 1 second defaults to 50 ISO, which is useless). The stack revealed several of the expected guide stars (and a couple of satellites) but no unambiguous Vesta. I'll try again with a deeper stack (20 + images, and some dark frames for noise reduction if the weather clears up before the Moon comes out again (around the 12-13th).

For the Samsung s24 I took a single 10 second shot at ISO 3200, this *just* revealed Vesta (see image above), so if the clouds go away I will try stacking multiple shots with the S24. 

Free Stacking software includes Deep Sky Stacker and Autostakkert for Windows,  and StarStaX for macOS.


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Monday, March 04, 2024

 

Thursday March7 to Thursday March 14

The New Moon is Sunday March 10. Jupiter is low in the north-western sky but still dominates the early evening sky. On the 14th the crescent Moon is near Jupiter. Venus is visible in the morning twilight below Mars. On the 8th the crescent Moon, Mars and Venus form a line, on the 9th the thin crescent Moon is close to Venus, Mars continues to climb away from Venus as the week progresses.

The New Moon is Sunday March 10. The Moon is at perigee, when it is closest to the Earth, on the 10th as well.

Evening sky on Thursday, March 14 as seen from Adelaide at 20:30 ACDST (60 minutes after sunset). Jupiter is low above the north-western horizon and near to the crescent Moon.  The inset is the telescopic view at this time.





    

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes after sunset).

Morning sky on Friday, March 8 as seen from Adelaide at 06:13 ACDST, (60 minutes before sunrise, click to embiggen). Venus and Mars and the crescent Moon form a line. The inset in the approximate telescopic view of Venus at this time.




 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).
 
Morning sky on Saturday, March 9 as seen from Adelaide at 06:14 ACDST, (60 minutes before sunrise, click to embiggen). Mars and Venus are close, but get progressively further apart over the week. The thin crescent Moon is close to Venus and can be seen together in binoculars. The inset in the approximate binocular view of Venus and the Moon at this time.



 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).
 
Whole sky on Saturday, March 10 as seen from Adelaide at 21:08 ACDST, 90 minutes after sunset (click to embiggen). Jupiter is low in the north-west.


Orion is almost due north. Bright Sirius is high in  the eastern sky. Between the bright star Canopus and the Southern Cross are a wealth of binocular objects to discover. With the Moon new, this is an excellent time to hunt the fainter clusters.

 

   

 Elsewhere in Australia will see a similar view at the equivalent time (90 minutes after sunset).

 

 

Mercury is lost in the twilight.

Venus is in the morning twilight, it is sinking towards the horizon but will remain visible for all of March. Mars and Venus draw further apart. On the 8th the crescent Moon, Mars and Venus form a line, on the 9th the thin crescent Moon is close to Venus

Mars is rising in the morning twilight and moving away from Venus. 

Jupiter is visible low in the early evening sky. On the 14th the crescent Moon is near Jupiter.

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/





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Monday, February 26, 2024

 

Thursday February 29 to Thursday March7

The Last Quarter Moon is Monday March 4. Jupiter is low in the north-western sky but still dominates the early evening sky. Venus is visible in the morning twilight below Mars. Mars  continues to climb away from Venus as the week progresses.

The Last Quarter Moon is Monday March 4.

Evening sky on Saturday, March 2 as seen from Adelaide at 21:18 ACDST (90 minutes after sunset). Jupiter is low above the north-western horizon.  The inset is the telescopic view at this time.





    

Similar views will be seen from the rest of Australia at the equivalent local time (90 minutes after sunset).

Morning sky on Saturday, March 2 as seen from Adelaide at 06:07 ACDST, (60 minutes before sunrise, click to embiggen). Venus and Mars are close, but get progressively further apart over the week. The inset in the approximate telescopic view of Venus at this time.



 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).
 
Whole sky on Saturday, March 2 as seen from Adelaide at 21:18 ACDST, 90 minutes after sunset (click to embiggen). Jupiter is low in the north-west.


Orion is almost due north. Bright Sirius is high in  the eastern sky. Between the bright star Canopus and the Southern Cross are a wealth of binocular objects to discover.

 

   

 Elsewhere in Australia will see a similar view at the equivalent time (90 minutes after sunset).

 

 

Mercury is lost in the twilight.

Venus is in the morning twilight, it is sinking towards the horizon but will remain visible for all of March. Mars and Venus draw further apart.

Mars is rising in the morning twilight and moving away from Venus. 

Jupiter is visible low in the early evening sky.

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/





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Tuesday, February 20, 2024

 

This Full Moon, lets use a simple method to measure distance to the Moon

I don’t know about you folks, but the feed in the social media formerly known as twitter is currently dominated by “cute poop” ads (who seem to have displaced the chemtrailers) and flat earthers. 

The former is a mildly puzzling Japanese phenomenon, while the latter appears to be dominated by people who have not progressed past a pre-Babylonian view of the world, but who possess P1000 cameras they don’t know how to focus. 

Now as a long-time viewer of the the skies and their wonders, these folks give me the screaming irrits, but I take this as a chance for a teachable moment, and get people involved in measuring the distance to the Moon in a way that anyone can undertake. One of the tenets of the flat earth movement is that the sun and moon are both small and local (that sound you are hearing is the ghost of Aristarchus howling at the said Luna). 

 Now, Aristarchus used the time it took for earth's shadow to cross the Moon in a lunar eclipse and got a figure that was 1/3 the modern distance, not bad for unaided eye observation without modern clocks (and thousands of times further than the flat earth requirement of “local”). 

Now there are no convent total lunar eclipses this year, so we can’t reproduce Aristarchus’s methods. 

The most common method for determining the distance to the moon, if you are not bouncing lasers off the mirrors left by the Apollo Astronauts or Soviets, is parallax. For parallax you and a mate a couple of hundred kilometers away have to take an image of the Moon at the same Universal Time, close to one or more bright stars, with equipment that gives an image of roughly the same scale. And you both need clear skies. Then all you have to do is measure the distance between the stars and the moon, do a bit of maths and viola, you have the distance to the Moon. 

Probably the next best time for parallax is May 23, when the Moon is close to delta Scorpii. Of course, all this requires a bit of organisation, as does most of the demonstrations of the sphericity of earth. 

Fortunately, this is a way to determine the distance to the Moon that one can do just by themselves. All you need is a digital camera with a decent optical zoom function (or attached to a telescope), an accurate timestamp function, a clear horizon, and the patience to take images for most for the night, and an image analysis program like AstroimageJ to measure the Moons diameter https://www.astro.louisville.edu/software/astroimagej/index.html  or a Python script.

 

The basic idea is that the moon at moon-rise is further away than the moon at the zenith by approximately the radius of the earth. (see figure 1, from https://arxiv.org/ftp/arxiv/papers/1405/1405.4580.pdf used under that fair use for research provisions).

All you have to do is measure the radius of the Moon as it rises and the radius of the Moon when it is highest, as well as an accurate measurement of the time the images were taken apply a bit of maths with the radius of the Moon and hey presto, the distance to the Moon! (full details in “The simplest method to measure the geocentric lunar distance: a case of citizen science” at https://arxiv.org/ftp/arxiv/papers/1405/1405.4580.pdf)



(Figure 2, from https://arxiv.org/ftp/arxiv/papers/1405/1405.4580.pdf used under that fair use for research provisions). 

Well, of course it’s not that simple. Close to the horizon atmospheric distortion “squashes” the image messing with the accurate measurement of the radius (this is not the horizon illusion, where the Moon appears bigger, when, in fact it isn’t), also, it needs to be a full moon far from apogee or perigee, when there will be enough change in the Moons diameter as it reaches the furthest and nearest points in its orbit to mess up the calculation. 


The Full Moon of February 24th is such a Moon, and this is my challenge: to take images of the Moon between moon rise and the Moon at zenith, then measure their diameter (making sure the images a re time stamped in some way, usually file creation data in the image header will suffice, just make sure you cameras clock is set correctly). 

 

(Figure 5. Best fit of the measured apparent sizes (error-bars) to the theoretical model (continuous line. The shaded region
correspond to solutions statistically compatible with the observed apparent sizes at a 5% confidence level, from https://arxiv.org/ftp/arxiv/papers/1405/1405.4580.pdf .used with permission).

Of course then you have to run the Python scripts given in “The simplest method to measure the geocentric lunar distance: a case of citizen science” (at https://arxiv.org/ftp/arxiv/papers/1405/1405.4580.pdf. I did mention you needed python didn’t I? sadly, the links in that paper no longer work, but Jorge Zuluaga has kindly passed the scripts on to me so I can send them on.  This link takes you to the Zip file with the Python Scripts. https://drive.google.com/drive/folders/1FXCgbYINt3hBBSU3gPzaY13MgSNIbtL1?usp=sharing

 


(Figure 6. Instantaneous distance as a function of time elapsed since the first observation. from https://arxiv.org/ftp/arxiv/papers/1405/1405.4580.pdf .used with permission). 

You also need more than two Moon shots for the statistical analysis (see the figures and the linked paper). So, what do you think? Are you up for the challenge?

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Thursday February 22 to Thursday February 29

The Full Moon Moon is Saturday February 24. This is an apogee (or mini) Moon. Jupiter is low in the north-western sky but still dominates the early evening sky. Venus is visible in the morning twilight near Mars. Mars  begins to climb away from Venus as the week progresses.

The Full Moon Moon is Saturday February 24.  This is an apogee (or mini) Moon, with apogee on the 26th.

Evening sky on Saturday, February 24 as seen from Adelaide at 21:29 ACDST (90 minutes after sunset). Jupiter is low above the north-western horizon.  The inset is the telescopic view at this time.





    

Similar views will be seen from the rest of Australia at the equivalent local time (90 minutes after sunset).  

Morning sky on Saturday, February 24 as seen from Adelaide at 06:00 ACDST, (60 minutes before sunrise, click to embiggen). Venus and Mars are close, but get progressively further apart over the week. The inset in the approximate telescopic view of Venus at this time.



 

Similar views will be seen from the rest of Australia at the equivalent local time (60 minutes before sunrise).   
 
Whole sky on Saturday, February 24 as seen from Adelaide at 21:29 ACDST, 90 minutes after sunset (click to embiggen). Jupiter is low in the north-west.


Orion is almost due north. Bright Sirius is high in  the eastern sky. Between the bright star Canopus and the Southern Cross are a wealth of binocular objects to discover.The full Moon will make them hard to see though.

 

   

 Elsewhere in Australia will see a similar view at the equivalent time (90 minutes after sunset).

 

 

Mercury is lost in the twilight.

Venus is in the morning twilight, it will now sink towards the horizon but will remain visible for all of February. Mars and Venus are close but draw apart.

Mars is rising in the morning twilight and moving away from Venus. 

Jupiter is highest around civil twilight and is now visible low in the early evening sky.

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/





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