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

# posted by Ian Musgrave @ 2:14 pm 0 comments

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

# posted by Ian Musgrave @ 6:12 pm 0 comments

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

# posted by Ian Musgrave @ 9:44 pm 0 comments

Printable Black and White chart for locating Comet 12P 27April-27 May. Click to embiggen and print. Use with a red light torch (or a standard torch with red cellophane over it) to preserve your night vision.	Printable Black and White Binocular chart for locating Comet 12P from 27 April to 6 May. The circle represents the approximate field of view of 10x50 binoculars. The comet is within binocular range of nu Taurii until around 2 May. Click to embiggen and print. Use with a red light torch (or a standard torch with red cellophane over it) to preserve your night vision.
Printable Black and White Binocular chart for locating Comet 12P from 6 May to 18 May. The circle represents the approximate field of view of 10x50 binoculars. The comet is within binocular range of nu Eriandus until around 13 May. Click to embiggen and print. Use with a red light torch (or a standard torch with red cellophane over it) to preserve your night vision.	Printable Black and White Binocular chart for locating Comet 12P from 18 May to 27 May. The circle represents the approximate field of view of 10x50 binoculars. The comet is within binocular range of Rigel until around 24 May. Click to embiggen and print. Use with a red light torch (or a standard torch with red cellophane over it) to preserve your night vision.
Photo realistic view of the evening sky simulated in Stellarium for Satday, April 27 as seen from Adelaide at 18:33 ACST (60 minutes after sunset, click to embiggen). Comet 12 P is within binocular range of nu Taurii.	Photo realistic view of the evening sky on Sunday, May 19 as seen from Adelaide at 18:45 ACST (90 minutes after sunset, click to embiggen). Comet 12P is close to the bright star Rigel in Orion (the inset is the approximate binocular view of the trio).

While the comet is still reasonably bright magnitude at 4.5, it remains low to the horizon over the next week or so. While it is slowly climbing above the horizon into darker skies, it is also slowly fading. You will definitely need binoculars, unless you are in a dark sky location, and then it will look like a fuzzy dot.

From the 27th April to the 3rd May  the comet will be within binocular distance of star nu Taurii (see charts, sweep west of Aldebaran for around two binocular widths). Although the comet is magnitude 4.5 -  4.6  at this time and theoretically dimly visible to the unaided eye, atmospheric extinction will mean it is more like magnitude 5. The comet will still look like a faint fuzzy dot.

At nautical twilight (and hour after sunset) on the 27th, it is almost 2 hand-spans above the horizon and the darkening twilight skies should help you spot it.  At astronomical twilight (an hour and a half after sunset) it will be a hand-span above the horizon (and you will need a level, unobstructed horizon to see it.

Using an ordinary camera, try zooming in around 3x and using multiple 1 second ISO 3200 exposures, but nothing below ISO 1600. (I was success full with 1 second 3200 ISO, I have also done 2 and 4 second exposures, but I have an S24, so that’s cheating). I have yet to try stacking, there may be too few stars visible to stack reliably until later in the week.

There there are no good guide stars until 9-12 May when it is close to nu Eridanus (sweep west from Bellatrix), when it is around magnitude 5, and then it passes by Orion, and is with binocular distance of bright Rigel from the 18th-24th. Although 12P will be approaching magnitude 6, this should be an excellent opportunity for wide field astrophotography with the comet almost 3 hand-spans from the horizon at astronomical twilight, when the sky is fully dark, near the iconic Orion constellation, with the first quarter Moon not interfering too much.

Labels: 12P, astrophotography, binocular, comet

# posted by Ian Musgrave @ 2:08 pm 0 comments

Printable Black and White chart for locating Comet 12P 10April-10 May. Click to embiggen and print. Use with a red light torch (or a standard torch with red cellophane over it) to preserve your night vision.	Printable Black and White Binocular chart for locating Comet 12P. The circle represents the approximate field of view of 10x50 binoculars.Click to embiggen and print. Use with a red light torch (or a standard torch with red cellophane over it) to preserve your night vision.
Photo realistic view of the evening sky simulated in Stellarium for Sunday, April 14 as seen from Adelaide at 18:48 ACST (60 minutes after sunset, click to embiggen). Jupiter is very low above the north-western horizon and within binocular distance of Uranus and the comet 12P (the inset is the approximate binocular view of the trio).	Photo realistic view of the evening sky on Sunday, April 21 as seen from Adelaide at 18:39 ACST (60 minutes after sunset, click to embiggen). Jupiter is almost lost above the north-western horizon. Comet 12P is close to the pair of Xi and omicron Tau (the inset is the approximate binocular view of the trio).

While the comet is a reasonably bright magnitude 4.5, about as bright as the star Taygeta (19 Tau) in the Pleiades, it is so low to the horizon that you will be difficult to see it through the horizon murk over the next week or so. You will definitely need binoculars, even if you can see the brighter stars of the nearby Pleiades clearly. While the comet is much brighter than Vesta in the Vesta challenge, it is lower in the horizon murk and a more extended object, making it more of a challenge.

On the 14th  the comet will be within binocular distance of Jupiter. Although the comet is magnitude 4.5 at this time and theoretically dimly visible to the unaided eye, atmospheric extinction will mean it is more like magnitude 6. The comet will look like a faint fuzzy dot.

At nautical twilight (an hour after sunset) it will be around three finger-widths above the horizon (and you will need a level, unobstructed horizon to see it). You may have better success looking a bit earlier, when it will be higher despite the brighter twilight sky. Terry Lovejoy was successful in capturing the comet with 7x 1 second exposures at 100 ASA using a Sony A7iii.

Using a more ordinary camera, try zooming in around 3x and using mutiple1 second 100 ISO imaging (you WILL need a tripod for this). Higher ISO (ASA) values will make the sky brighter as well as the comet, so will not be as effective. You may wish to play around with the settings if you have time before the comet sets. 

UPDATE: forget everything I said about imaging. I have been able to get it with 1 second ISO 3200 and 3x zoom, but nothing below ISO 1600. (I have also done 2 and 4 second exposures, but I have an S24, so that’s cheating). I have yet to try stacking, there may be too few stars visible to stack reliably. 

12P Pons-Brooks will climb higher and brighten as it rises (not much though). It should be more or less easily located in binoculars by sweeping up from Jupiter (see printable charts and maps above).

On the 21st the comet will be at it's brightest (unless it undergoes another outburst, it has had nights where it was substantially brighter) at magnitude 4.4 (although atmospheric extinction means it is more like magnitude 5.3 at astronomical twilight, an hour after sunset). At this time it will be nearly two hand-spans above the horizon, almost on top of the two stars Xi and omicron Tau (both around magnitude 3 and readily visible, see charts above). If you can't readily see the pair locate the rather obvious Aldebaran (and the Hyades) and sweep down an to the west by about three binocular widths and the pair should be obvious.

Again, you may wish to look earlier when the comet is higher, and the twilight brighter. While the comet will still look like a fuzzy dot in binoculars, you may be able to see a short tail. 

For imaging try zooming in so the pair of Xi and omicron Tau take up a decent proportion of the field of view (not too  much as the resolution of most point and click cameras and mobile phones degrade severely on zoom) and take multiple 1 second images (I use between 10-20 images), you may try higher ISOs to try and capture more comet detail. Stack the images with an appropriate stacking software. Free Stacking software includes Deep Sky Stacker and Autostakkert for Windows,  and StarStaX for macOS. 

After this 12P Pons-Brooks begins to fade, but still remains "bright", sweeping your binoculars up from Xi and omicron Tau should pick it up. on the 29th it is within binocular distance of nu Tau (see charts, sweep west of Aldebaran for around two binocular widths). At this time, at nautical twilight is over two hand-spans from the horizon and magnitude 4.5 and another good opportunity for imaging.

Labels: 12P, Astrophiz, astrophotography, comet

# posted by Ian Musgrave @ 5:42 pm 0 comments

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 embiggen	Photorealistic 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,

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.

Labels: 4 Vesta, Asteroid, astrophotography, gimp

# posted by Ian Musgrave @ 10:25 pm 0 comments

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.

Labels: 4 Vesta, Asteroid, astrophotography

# posted by Ian Musgrave @ 12:55 am 0 comments

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.

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)

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

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

# posted by Ian Musgrave @ 10:03 pm 1 comments

Location of Minor planet (1) Ceres at 00:10 am ACDST on Sunday 26 March as seen from Adelaide. Similar views will be seen at the equivalent local time (click to embiggen)	Telescopic view of Minor planet (1) Ceres and galaxy M100 at 00:10 am ACDST on Sunday 26 March as seen from Adelaide. Similar views will be seen at the equivalent local time (click to embiggen)

Minor planet Ceres is at opposition at the moment, and is currently around magnitude 7, easily visible in binoculars even under suburban skies. Ceres is currently beyween Beta (β) Leonis (Denebola) and epsilon (ε) Virginis (Vindemiatrix). Over the next few days it is in an easily recognised cluster of dim stars, and Ceres can be seen moving from night to night.

On the late evening of the 25th, Early morning of the 26th Ceres is next to the spiral galaxy M100. At magnitude 9 it is too fail to be picked up clearly without a telescope, but is an interesting telephotography challenge. By the late evening 26th early morning 27th Ceres is n the other side of M100.

Chart suitable for black and white printing to help locate Ceres. Chart is at 00:10 am ACDST.  Note that the chart locations are out by 1 day fro come reason (even with a fresh Ceres download) so the 27th is in fact the 26th, the circle is the field of view of 10x50 binoculars. (click to embiggen and print)	Binocular chart suitable for black and white printing to help locate Ceres. Chart is at 00:10 am ACDST.  Note that the chart locations are out by 1 day fro come reason (even with a fresh Ceres download) so the 27th is in fact the 26th, the circle is the field of view of 10x50 binoculars. (click to embiggen and print)

Labels: astrophotography, binocular, Ceres, Opposition, telescope

# posted by Ian Musgrave @ 1:35 am 0 comments

Full Moon July 14 05:00 AEST. perigee July 13 19:00 (-9h, closest this year)	Full Moon December 8 14:00 AEST  Moon at apogee 12th +3d20h

July 14 is the best perigee Full Moon this year. The differences are in Full Moon size are subtle, especially if you compare tonight's Full Moon with the June 15 Full Moon which was also a perigee Full Moon.  

It requires a keen eye and good memory to distinguish a perigee "super" Moon from more ordinary moons, the best contrast is with the apogee "mini" moon of December 8, even though this is not a good apogee Moon). 

That doesn't mean you shouldn't try though. Daniel Fischer has been able to see the difference, you can read his account and viewing tips here
http://earthsky.org/space/can-you-discern-supermoons-large-size-with-the-eye-an-observer-says-yes

Photographing them can be more rewarding. You can see images of perigee Moon and apogee Moon pairs from 21 Jan 2019 here and 10 August 2014 here.Tips for photographing them are here.

A full Moon at perigee has been called a "Super Moon", this is not an astronomical term (the astronomical term is perigee syzygy, but that doesn't trip off the tongue so nicely), but an astrological one first coined in 1979 (see here).

Still, it is a good excuse to get people out and looking at the Moon (although technically the Moon was full at 5 am this morning and biggest as it was closest to perigee which occurred at 7 pm on the 13th, but the sky was covered in cloud then, it will still look good tonight).
 

Labels: astrophotography, Moon, perigee, unaided eye

# posted by Ian Musgrave @ 6:07 pm 0 comments

Venus 25/9/21 8" Newtonian, 2x Barlow, ToUCam at 640x480 resolution , 113 frames staked in Registax.	Venus 10/10/21 8" Newtonian, 2x Barlow, ToUCam at 640x480 resolution , 113 frames staked in Registax.
Venus 7/11/21 8" Newtonian, 2x Barlow, ToUCam at 640x480 resolution , 101 frames staked in Registax.	Venus 9/12/21 8" Newtonian, 2x Barlow, ToUCam at 640x480 resolution , 100 frames staked in Registax.

My 2021 Phases of Venus campaign has been somewhat disrupted, but I have still managed to capture so decent shots of the increasing size and increasing crescent phase of Venus. Still trying to optimize the gain, shutter speed for the best contrast, not tp mention focus, but not shabby despite my fluffing about.

Labels: astrophotography, telescope, Venus

# posted by Ian Musgrave @ 10:45 pm 0 comments

The ISS passing through Leo and above Venus and Mars around 19:10, Canon IXUS 1 seconds exposure, 20 images. Images stacked in ImageJ and a MAX-Z projection with brightness turned up.	Same sequence. Images stacked in Deep sky stacker and aligned on the stars then curves adjusted in GIMP. Click to embiggen.

This evening was excellent for the ISS pass.Clear and cloudless, the ISS passed through Leo above Regulus, Mars and Venus, a rather spectacular pass. Having Learn my lesson from the previous nightI went with  a train of 10 1 second exposures at ISO 1600. I captured most of the pass, with a gap due to timer delay i setting off the 10 shot train.

I stacked the images first in image J, aligned on the frames. The earth rotated in the 30 seconds the sequence took, so the stars and planets are trailed. Then I stacked in DeepSkyStacker aligned on the stars for comparison, the stars aren't trailed but the horizon is blurred and DeepSkyStacker dropped a few frames. Of course, with the camera chugging away by it self I could watch the pass which was rather nice indeed.

Animated GIF of the ISS under the Southern Cross

Labels: astrophotography, ISS, Satellite

# posted by Ian Musgrave @ 2:11 am 0 comments