Astroblog

Sky chart facing north west on Sunday, March 30 as seen from Adelaide at 06:02 ACST (90 minutes before sunrise, click to embiggen). The location of T CrB is shown with a circle. Similar views will be seen 90 minutes after Sunset elsewhere in Australia.	Printable black and White Sky chart facing north west on Sunday, March 30 as seen from Adelaide at 06:o2 ACST (90 minutes before sunrise, click to embiggen and print). The location of T CrB is shown with a dark square The field of view of 10x50 binoculars is shown with circle. Similar views will be seen 90 minutes after Sunset elsewhere in Australia.

Some recent postings about the "Blaze Star" T Coronae Borealis (T Crb) are suggesting it might go Nova Real Soon Now. It hasn't, but spectral indications suggest it may be ready to go "soonish" (where soonish is anywhere between now and November 2025).

Although you need to be up in the early hours of the morning to see it, T CrB goes nova roughly every 80 years, where it flaers from being invisible to the unaided eye to brighter than the brightest star in its constellation (~ magnitude 2).  So its worth while  keeping an eye out for this rare event.

Labels: astrophotography, citizen science, nova, T CrB

Sky chart facing north on Saturday, March 22 as seen from Adelaide at 05:56 ACST (90 minutes before sunrise, click to embiggen). The location of T CrB is shown with a circle. Similar views will be seen 90 minutes after Sunset elsewhere in Australia.	Sky chart facing north on Saturday, March 22 as seen from Adelaide at 05:56 (90 minutes before sunrise, click to embiggen). Constellation names and lines are shown for clarity.

My image of Corona Borealis taken on 10 August with my Samsung S24 in astrophography mode at 5x zoom. Stars down to magnitude 7.5 are visible. The approximate location of T CrB is shown with a star above Ɛ CrB.	AAVSO chart of Corona Borealis showing the magnitude of surrounding stars. The decimal points have been omitted eg 22 is 2.2, 89 is 8.9

T Coronae borealis (T CrB) did not go Nova Last September as predicted. However, Thuringian State Observatory noticed the emission lines in the spectrum of T CrB have risen sharply, indicating a greatly increased accretion rate, and possibly an outburst is coming soon. See also https://www.astronomerstelegram.org/?read=17041

Unfortunately, Corona Borealis is in the morning sky now, so you have to get up at dark o'clock to see it.

If you look to the North in the morning at astronomical twilight (90 minutes before sunrise), you will see a prominent bright orange star, Arcturus (see top chart), if you look downwards and to the right you will see a dainty circlet of stars. Corona Borealis, the northern crown.

While pretty in its own right, it houses a most unusual star, T Coronae borealis (T CrB), also known as the blaze star. T CrB is a recurrent nova, a binary system where gas from a red giant star accretes on a white dwarf companion. Eventually the gas builds up to a density where a nuclear explosion occurs and this is seen as  a nova. 

A recurrent nova is one where there is a (semi) regular patter of repeated outbursts. T CrB seems to erupt every 80 years, with the last in 1946. Recent patterns of brightening and dimming look like the pre outburst phase of the 1946 eruption. It was predicted that T CrB may go nova between August and the end of September 2024. That didn't happen, but the new spectral changes may herald the long awaited outburts

When that happens, T CrB will rapidly rise to from its current magnitude 10 (well below eye or binocular visibility)  around magnitude 2 about the same brightness as Alphecca, 𝛂 Coronae Borealis (see bottom left-hand panel), the brightest star in the constellation. It will only remain above unaided eye visibility for a week or so. 

T CrB is located on the right-hand side to the circlet, just above Ɛ CrB (see bottom left-hand panel) where the line of stars turn down, there are no other bright stars in the region, so when it erupts it will be easily visible.

The challenge:  

Take an image of Corona Borealis every clear morning during March-April awaiting the eruption. You will need a stack of ~ 10 images at high ISO of around 1 second duration, then stacked in appropriate software to pick up the faint stars. It would be best if you zoomed in so that Corona Borealis occupies most of the camera field (with a bit of space on the right-hand side so you don’t miss out on T CrB. That way hopefully you will catch not only the eruption, but the fade as well, doing a bit of backyard astrophysics. 

Be patient, after a few night astrophotography you will become familiar with the stars and will easily see when T CrB erupts. 

You can also follow the T CRB Nova Watch on Space weather (in the the righthand panel). Currently magnitude 10.

Labels: astrophotography, citizen science, nova, T CrB

The Moon as seen  from Adelaide looking Northeast at 19:30 ACST, (astronomical twilight, 90 minutes after sunset) similar views will be seen for other parts of Australia at the equivalent local time (90 minutes after sunset) . Click to embiggen. The insets show the telescopic view of Saturn at this time.

Saturday 14 September is  International Observe the Moon Night. An international initiative to get people out and observe our beautiful nearest neighbor. You don't need much, just your unaided eyes, but even binoculars or a small telescope will greatly aid your appreciation of our Moon. 

This weekend the Moon is three days past first quarter and above the North-east horizon not far from the planet Saturn. It also forms another line with the bright stars Altair and Vega. All in all a lovely sight.

While not quite as good as Last Quarter, it is a good phase as the terminator, the light dark boundary on the Moons surface, is close to may interesting craters that are at their best at this sun angle.

A telescopic simulation of the appearance of the Moon at 19:30 ACST, (astronomical twilight, 90 minutes after sunset), several prominent craters are visible, particularly prominent are the Clavius and Logmontanus at the south pole (near the bottom) and Copernicus (two thirds of the way to the north/top). 

The prominent dark areas, the Sea of Tranquility, the sea of serenity and the sea of showers (which form the eyes and chin of  "the man in the Moon" are easily seen with the unaided eye.  Click to embiggen.

Even with modest binocular craters can be seen along the Moons terminator. A small telescope reveals a wealth of detail, and finding and focusing on the Moon is so much easier than any other class of astronomical object. You can use this map to identify the features you see (the map is upside down from our perspective). This interactive map will help you explore more.

You may wish to try some astrophotography with a mobile phone or a point and shoot camera. Follow the links for hints on imaging the Moon with these systems.

Even if you don't have a telescope, just go out and look to the north-east (and the west, where Venus and Spica dominate the horizon, with Scorpius above), the view will be lovely. Around 19:40 you may even see a satellite or two pass over. If you don't have a telescope, a local astronomical club may be having an  International Observe the Moon Night near you. Check out this map for locations.

So if the sky is clear, go out and have a look!

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/

 

Labels: citizen science, Moon, public outreach, unaided eye

Sky chart facing north on Saturday, August 17 as seen from Adelaide at 19:11 ACST (90 minutes after sunset, click to embiggen). The location of T CrB is shown with a circle. Similar views will be seen 90 minutes after Sunset elsewhere in Australia.	Sky chart facing north on Saturday, August 17 as seen from Adelaide at 19:11 ACST (90 minutes after sunset, click to embiggen). Constellation names and lines are shown for clarity.

My image of Corona Borealis taken on 10 August with my Samsung S24 in astrophography mode at 5x zoom. Stars down to magnitude 7.5 are visible. The approximate location of T CrB is shown with a star above Ɛ CrB.	AAVSO chart of Corona Borealis showing the magnitude of surrounding stars. The decimal points have been omitted eg 22 is 2.2, 89 is 8.9

If you look to the North at astronomical twilight (90 minutes after sunset), you will see a prominent bright orange star, Arcturus (see top chart), if you look downwards and to the right you will see a dainty circlet of stars. Corona Borealis, the northern crown.

While pretty in its own right, it houses a most unusual star, T Coronae borealis (T CrB), also known as the blaze star. T CrB is a recurrent nova, a binary system where gas from a red giant star accretes on a white dwarf companion. Eventually the gas builds up to a density where a nuclear explosion occurs and this is seen as  a nova. 

A recurrent nova is one where there is a (semi) regular patter of repeated outbursts. T CrB seems to erupt every 80 years, with the last in 1946. Recent patterns of brightening and dimming look like the pre outburst phase of the 1946 eruption, and it is predicted that T CrB may go nova between now and the end of September this year. 

When that happens, T CrB will rapidly rise to from its current magnitude 10 (well below eye or binocular visibility)  around magnitude 2 about the same brightness as Alphecca, 𝛂 Coronae Borealis (see bottom left-hand panel), the brightest star in the constellation. It will only remain above unaided eye visibility for a week or so. 

T CrB is located on the right-hand side to the circlet, just above Ɛ CrB (see bottom left-hand panel) where the line of stars turn down, there are no other bright stars in the region, so when it erupts it will be easily visible.

The challenge:  

Take an image of Corona Borealis every clear night during Ausgust-September awaiting the eruption. You will need a stack of ~ 10 images at high ISO of around 1 second duration, then stacked in appropriate software to pick up the faint stars. It would be best if you zoomed in so that Corona Borealis occupies most of the camera field (with a bit of space on the right-hand side so you don’t miss out on T CrB. That way hopefully you will catch not only the eruption, but the fade as well, doing a bit of backyard astrophysics. 

Be patient, after a few night astrophotography you will become familiar with the stars and will easily see when T CrB erupts. 

You can also follow the T CRB Nova watch on Space weather (in the the righthand panel). Currently magnitude 19.

Labels: astrophotography, citizen science, nova, T CrB

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?

Labels: astrophotography, citizen science, Moon

 

Labels: citizen science, eclipse, Moon, public outreach, unaided eye

The Moon as seen  from Adelaide looking Northwest at 19:40 ACST, (astronomical twilight, 90 minutes after sunset) similar views will be seen for other parts of Australia at the equivalent local time (90 minutes after sunset) . Click to embiggen. The Moon forms a line with Jupiter and Saturn.

The insets show the telescopic views of  Jupiter and Saturn at this time.

Saturday 26 Sptember is  International Observe the Moon Night. An international initiative to get people out and observe our beautiful nearest neighbour. You don't need much, just your unaided eyes, but even binoculars or a small telescope will greatly aid your appreciation of our Moon.

This weekend the Moon is three days past first quarter and above the North-west horizon forming a line with the planets Saturn and Jupiter. It also forms another line with the bright stars Altair and Vega. All in all a loverly sight.

While not quite as good as Last Quarter, it is a good phase as the terminator, the light dark boundary on the Moons surface, is close to may interesting craters that are at their best at this sun angle. 

A telescopic simulation of the appearance of the Moon at 19:40 ACST, (astronomical twilight, 90 minutes after sunset), several prominent craters are visible, particularly prominent are the Clavius and Logmontanus at the south pole (near the Moon label) and Copernicus (two thirds of the way to the north/bottom). The prominent dark areas, the Sea of Tranquility, the sea of serenity and the sea of showers (which form the eyes and chin of  "the man in the Moon" are easily seen with the unaided eye.  Click to embiggen.

Even with modest binocular craters can be seen along the Moons terminator. A small telescope reveals a wealth of detail, and finding and focusing on the Moon is so much easier than any other class of astronomical object. You can use this map to identify the features you see (the map is upside down from our perspective). This interactive map will help you explore more.

You may wish to try some astrophotography with a mobile phone or a point and shoot camera. Follow the links for hints on imaging the Moon (and also Jupiter) with these systems.

Even if you don't have a telescope, just go out and look the the north-west, the view will be lovely. Around 19:40 you may even see a satellite or two pass over. Including a relatively bright Hubble Space Station pass.

If you don't have a telescope, a local astronomical club may be having an  International Observe the Moon Night near you. Check out this map for locations.

So if the sky is clear, go out and have a look!

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/

 

Labels: citizen science, Moon, public outreach, unaided eye

Evening sky looking south as seen from Adelaide at 18:43 ACST at astronomical twilight (90 minutes after sunset). The southern cross is almost directly south and high above the horizon. Click to embiggen.

Sunday June 21 is the solstice, when the night is longest. It is also the night of the new Moon and time for a light pollution monitoring ebent.

The event is an attempt to set a world record for light pollution mapping put on by the Australasian Dark Sky Alliance, details here
https://worldrecordlight.thinkific.com/pages/how-to

You will have to register and do a short lesson on magnitude estimation. The all you have to do is go out and look south on the night of the 21st and contribute to our understanding of light pollution and the creeping loss of our magnificent night skies. There may even be a nice ISS pass to enjoy as well.

Even if it is cloudy you can still add to the record.  Cloud cover predictions can be found at SkippySky.

If you are not sure how to find south, Google maps or any street directory will show you south (or see the chart above, find the Southern Cross and you have found South).

Labels: citizen science, light pollution

January 31 Eclipse just at the end of the eclipse, 00:38, when the Earth is almost directly between the Sun and the Moon	July 28 Eclipse just at the end of the eclipse, 06:45 am, when the sun is almost about to rise and a disk Earth would be edge on.

For some reason there has been a rise in the number of people who think the Earth is flat. They dismiss the images of Earth from Space as "NASA lying to us", despite the number of different space agencies (Russia, China, India, Japan) involved.

There are many ways you can prove the Earth is round (or at least and oblate spheroid) yourself with no particularly sophisticated equipment. However, most involve having at least one helper thousands of kilometres apart or international travel.

However, this year there with two total lunar eclipses there is an opportunity to show that the earth is round all by yourself, you just have to wait 6 months.

A lunar eclipse shows that the Earth is round (as you can see the round edge of the Earth's shadow creeping over the Moons surface see also here), but this could be argued to be the same if the earth was a flat disk.

However, Lunar eclipses  also occur with the sun at varying angles to the Earth. This will not matter for a spherical Earth, but a disk shaped Earth will show different shadow shaped depending on weather the eclipse is with the sun directly behind the Earth or if it is just rising.

The January 31 total Lunar eclipse occurs near midnight in Australia, but the July 28 total Lunar eclipse occurs near dawn (The Jan 31 eclipse is also close to perigee, while the July 28 eclipse iwll be close to apogee, so you should get nice size contrasts).

So if you photograph the January and July total lunar eclipses, an the Earth's shadow is a circle at both times, you have shown the Earth is a sphere (or at least a spheroid).

Over to you.

Labels: citizen science, eclipse, Moon, public outreach

Recent research has suggested the weird orbit of the icy worlds Sedna and six others could be explained if there is a Neptune sized object lurking at the very fringes of the solar system. This would be an amazing find. Unlike the discovery of Neptune however, where Neptune was found within one degree of its predicted location, the location of the putative Planet 9 is poorly constrained. Hunting for it involves searching through many, many images looking for tiny dots that move.

Now you can be involved in the hunt! ANU astronomers have set up a citizen science page where you can help in the hunt for Planet 9. It involves watching a lot of tiny dots bounce about, but you could discover a new world!

Labels: citizen science, Pluto, public outreach

Most people will be somewhat aware that the US budget sequester has had a wide range of impacts, amongst which are the education and outreach services of NASA. Faced with suspension or closing down, the educators are trying to do something to keep going. In the words of Pamela Gaye.

Faced with governmental funding cuts to science education and research, we have decided to go old school with a twist: On June 15-16, we are hosting a telethon using Google Hangout on Air – a Hangout-a-thon – to raise money to support public engagement in science.

If you want to be part of this awesome hangout here's where you find out more.
- Blog post: http://bit.ly/18U733k
- Schedule of Events: http://bit.ly/15VFNgv
- FB Event: http://on.fb.me/15VNyTD

It starts Saturday 15 June at  11:00am US central time (UTC -5 hours, that's Sunday, 16 June 2013 at 1:30:00 AM, in Australian Central Time, and 2:00 AM AEST). There's a great line-up, and lot's of citizen science and activities for everyone.

Labels: citizen science, Science Blogging, science communicators

Remember  the Solargraphy project? This  multi-month solar photography project organised by the Royal Institution (Australia) using home-made pinhole cameras has finally come to an end.

My Kayaking mate and I have taken our cameras down (see debris above), scanned the images and sent them in. The right hand image is my attempt to process the raw image. The bright white lines are the sun passing through the sky over two months, the gaps are caused by clouds. You can also see the neighbours roofs, trees on the horizon and telegraph poles (plus dots that are probably due to rain getting in).

As I noted, I tried to set the camera to get the best horizon shot, but I ended up aiming the camrea too low, and the bottom half of the image (cropped away) was jts darkness.

Still what I got was pretty good, and you can clearly see e movement of the sun over the weeks.

Labels: astrophotography, citizen science, public outreach, science, Sun

You may, or may not, have heard of Laneway Learning. In a Melbourne laneway cafe people come together for relatively informal learning sessions. Learning with Lattes if you like.

Well, my mate and fellow iTelescoper Peter Lake has a laneway learning session. He will be doing citizen science, and teaching astronomy by tracking asteroids with remote telescopes.

If you live in Melbourne and have a hankering for Astronomy, why not try this session?

Labels: Astronomy, citizen science, iTelescope, Public Lecture

The Hubble telescope has produced some of the iconic images of space, and you can get lost going through the published images.

Yet there are thousands of images that have never been seen by the public. So Hubble is throwing open its archives to the public to look for interesting images.

Some assembly is required, you will need to do some processing of the image data. There is a series of tutorial to help you though.

There is even a competition with prizes (see here and here), but you have to hurry. The competition closes May 31!

More information from the Hubble site:

• How to find hidden treasures in the archive
• What is image processing?
• Hubble’s Hidden Treasures 2012 Contest
• Hubble's Hidden Treasures 2012 Image Processing Contest
• Who is organising this?

Hat tip to the Bad Astronomer.

What, you are still here? Hie thee to the Hubble site this instant.

Labels: astrophotography, citizen science, competition, hubble

NASA has announced new citizen science project called Target Asteroids! where it will recruit amateur astronomers to monitor asteroids to support the OSIRIS-REx asteroid mission (which amongst other things will return wit a sample of asteroid).

You can read the press release here, and go direct to the Target Asteroids! site here.

Labels: asteroids, citizen science, miscelaneous

Here's an amazing project for Australian Citizen Scientists to get involved in. Via the Royal Institution (Australia), you can be involved in a multi-month solar photography project, the Solargraphy project. Just email the good folks at RiAus for the special photography paper, and follow the instructions here to make the ultra-cheap pinhole camera, expose for a couple of months and viola!

You can even enter your photos into the Solargraphy Project exhibition as part of the Winning Sky Photos: the David Malin Awards 2011 exhibition (if received before 5pm on 31May 2012).

Give it a go! I am!

Labels: astrophotography, citizen science, science

The folks who bought you GalazyZoo and PlanetHunters have a new quest for you, finding Kupier Belt objects. Yes, join in Ice Hunters and help find KBOs, if you are lucky, your faint ice-ball will be selected as the target for the New Horizons mission after it flies past Pluto. Read the introduction here.

Labels: citizen science, Pluto, Zooniverse