Bearing Witness

October 11, 2021

I wrote a post about Jehovah’s Witnesses in 2017, “Mr & Mrs JW: I have some questions…” If words are not enough to convince you of the problems with this organisation, you should watch the September 2021 Australian Broadcasting Corporation Four Corners episode: Bearing Witness.

source: ABC Four Corners

Waiting for U Sco: nearby gamma ray transient detected

September 29, 2021
The Fermi Gamma-ray Space Telescope (source: NASA)

Two days ago I wrote Waiting for U Sco. Today, here are a few excerpts from ATel #14941 (The Astronomer’s Telegram):

The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has detected a new transient gamma-ray source, Fermi J1623-1752.

A possible counterpart to the LAT transient is the recurrent nova U Scorpii with position offset by 0.18 deg from the LAT position, thus just outside the 95% confidence error circle, but within the 99% confidence error circle. U Sco has a known recurrence interval of 10.3 years (Schaefer 2010, ApJS, 187, 275) prior to its outburst in January 2010, thus a new outburst from U Sco could be anticipated. The last observation of U Sco in the AAVSO lightcurve database was on 2021 Sep 19.

Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing activity of this source, we encourage multi-wavelength observations, particularly optical follow-up of U Sco.

ATel #14941

I read about this in a post by Alexandre Amorim (Brazil) in the AAVSO novae forum. Robert Fidrich (Hungary) soon followed up with an iTelescope observation to say that there was no eruption visible.

Given that U Sco almost certainly had an outburst in its “seasonal gap” (unobservable due to position on the sky), probably in 2017, what this current gamma ray event means seems pretty uncertain.

I’ll continue imaging the U Sco region until it’s too low tonight (in between the clouds) and, consistent with my last post, whenever I can thereafter.

Waiting for U Sco

September 27, 2021

When the recurrent nova U Sco goes into outburst again, the image below shows where it will appear (see cross-hair style position marker), with the bright star Antares, and those bracketing it, shown for reference:

source: Stellarium

Zooming in shows two stars to the right of the nova position marker. Looking at previous outbursts, U Sco’s peak brightness should be somewhere between these two (around magnitude 7.5 to 8, so a binocular or small telescope object).

source: Stellarium

I’m taking images from my backyard of the U Sco region when I can. The image below (click it to enlarge) was taken on Sep 10 2021. I’ve taken a few since but want to step up the regularity. The red arrow shows where U Sco will appear and the green arrow shows the two stars pointed to above.

In any case, I won’t have the same cause to complain about missing the next outburst of U Sco that Leslie Peltier did about missing the T CrB outburst in 1946 (as related near the end of a recent talk I gave about RS Oph), given that my observing frequency is likely to be less and over a much shorter timeframe.

Addendum: Having said all this, given that there was almost certainly an unobserved eruption in the 2017 seasonal gap, as announced in a March 2019 AAVSO forum post, what does this imply for the prediction made by Brad Schaefer of 2020+/-0.7 in a paper published in June 2019? And yet, see the next post…

The Crab Nebula

September 25, 2021

We live only a few conscious decades, and we fret ourselves enough for several lifetimes.

(Christopher Hitchens)

I recently gave a 5 minute talk to a non-technical group about the Crab Nebula (M1, the first object in Charles Messier’s catalog) that related to a sense of wonder in Science. I thought the brief content was worth sharing here.

Chinese astronomers in 1054 witnessed a “guest star”, an explosion that gave rise to a remnant several light years wide called the Crab Nebula.

The object is several thousand light-years distant from earth, yet visible in a small telescope, although with nothing like the detail shown in the Hubble Space Telescope image of Figure 1!

Figure 1: The Crab Nebula, a Hubble Space Telescope image mosaic (source: NASA)

At the heart of the nebula is an object composed only of neutrons, a spoonful of which would weigh a billion tonnes, spinning 30 times per second, energising the nebula, wave-like rings expanding outward from the centre like ripples in a pond (Figure 2).

The original star ran out of the elements that had sustained its nuclear fusion for millions of years, its core collapsing then rebounding in a fraction of a second, ending as a supernova explosion.

Figure 2: The central region of the Crab Nebula (source: NASA)

The event synthesised elements heavier than iron that spread out into the space between the stars, to be incorporated into new stars and their planetary systems, some perhaps going on to develop life.

The iron in our blood, along with trace elements like zinc and iodine, come from such stars.

So, not only are we star-stuff, as Carl Sagan liked to say, but in fact we owe our existence to massive stars that burned bright and lived short lives (millions vs the billions of years our sun will last) then died, so that we could live for just a few decades.

RS Ophiuchi talk for The Astronomical Society of South Australia

September 4, 2021

A few days ago, on September 1 2021, I gave a short talk (15 minutes) to the Astronomical Society of South Australia about RS Ophiuchi and the 10 known recurrent novae more generally.

The talk starts at the 1 hour 7 minute 39 second mark (cued up here) in the YouTube video after the main speaker, Associate Professor Gary Hill, who gave a talk about observing astronomical phenomena with high energy neutrinos using a neutrino observatory he helped to construct in Antarctica. He was a hard act to follow.

On the subject of RS Ophiuchi, here is an updated visual light curve for September 4 2021 with my binocular observations in purple.

One thing I talked about was the most recent and the next predicted outbursts of recurrent novae. I neglected to add U Scorpii to the list which is predicted to go into outburst in the next year or two. Unlike T Corona Borealis which is likely to reach magnitude 2.5 or 3 sometime before 2026, U Sco will only be magnitude 7.5 or 8 at maximum (starting from around magnitude 18), fading by several magnitudes within a week.

RS Ophiuchi Decline Continues

August 16, 2021

The expected decline of the recurrent nova RS Oph continues, almost 3 magnitudes in 7 days. I’ve managed only 5 observations with a couple of cloudy nights between the last two. Luna at 60% illumination in nearby Scorpius tonight made estimating its magnitude (7.2) in 7×50 binoculars a little trickier tonight.

Recurrent Nova RS Ophiuchi Update

August 12, 2021

Since my Aug 9 observation of RS Oph, the AAVSO alert notice was published by Sara Beck: Alert Notice 752: Rare Outburst of Recurrent Nova RS Ophiuchi. My 4.5 visual estimate was listed there along with others from Australia, Brazil, the UK, the US, Belgium and Russia.

The next night was cloudy and wet, but there were enough clear periods tonight for another estimate, 5.7 visual, as shown below:

The last 2 years of RS Oph visual data (including photometry from CCDs, DSLRs)

The next two plots show more detail:

The last week of RS Oph visual data
The last few days of RS Oph visual data

I suggested in my last post that based upon previous outbursts, RS Oph will have reduced by 1 magnitude in 2 days, which it has done. A little more actually, from 4.4 on Aug 9 to 5.7 on Aug 11.

These objects are a reminder that we live in a violent, ever changing universe.

Recurrent Nova RS Ophiuchi in outburst!

August 10, 2021

The recurrent nova RS Ophiuchi is in outburst for the first time since 2006!

Other known outbursts were observed in 1985, 1967, 1958, 1933, and 1898.

RS Oph outbursts since 1933

The current outburst is shown at upper right of the plot that includes outbursts from 1933 onward.

Around 15 visual observations of the current outburst had been recorded in the AAVSO International Database and the nova had reached around magnitude 4.6 at the time I started writing.

The nova will be visible to the unaided eye from some locations and easily visible in binoculars from suburban locations (at least here in South Australia).

Only a handful of recurrent novae are known and the time between outbursts tends to be measured on a timescale of decades, averaging 20 years for RS Oph but varying +/- 10 or so years.

These systems involve a giant star (in this case, a slow irregular variable with a period of a few hundred days) and a white dwarf star pair in which mass is transferred from the giant to the white dwarf, forming an accretion disk which eventually undergoes a runaway thermonuclear reaction.

Example of a Cataclysmic Variable (RS Oph) from http://apod.nasa.gov/apod/image/0607/rsoph_pparc_big.jpg
Artist’s impression of RS Oph (from APOD)

RS Oph is around 5000 light years distant and so of course, the event we now see happened around 3000 BC.

The magnitude of the RS Oph binary star system increases rapidly from magnitude 10 or 11 to around 4.5 in the space of day, taking around 100 days to return to the baseline in a characteristic decay curve.

Within 2 days it will diminish by around 1 magnitude and by around 2 magnitudes within 5 days.

So, clear skies would be nice! The local forecast does not look great for Adelaide over the next few days.

It was cloudy by the time I read the outburst notification tonight and first started writing this post, but the sky cleared at around 1 am!

I observed the nova low in the west through 7×50 binoculars and estimated its magnitude to be 4.5 (Julian Date 2459436.16237 which is almost 15:54 UT or 01:24 Australian Central Standard Time):

The last month or so of observations. My magnitude 4.5 observation is shown in the cross-hairs.
The last few days of observations. My magnitude 4.5 observation is shown in the cross-hairs.

The 43 and 46 comparison stars (at about 5 and 11 o’clock with respect to the nova) on the following AAVSO finder chart were used for the estimate:

The finder chart needs to be rotated clockwise somewhat more than 90 degrees but less than 180 degrees to match the orientation of the sky shown in the Stellarium image below:

Note the position of the three roughly magnitude 3.5 stars in a straight line above the nova which is below and to the right of the middle of these stars (in the Stellarium image), with Scorpius at far left. These 3 stars occupy much of the finder chart near the nova (which is above and to the right of the middle star on the chart).

While every variable star type has its own interesting qualities, I find novae to be the most fascinating sub-type of cataclysmic variables and probably of all variable types because of the power and unpredictability involved. They are a reminder that we live in a violent, hostile yet endlessly fascinating universe, that we are, as Bernard Lovell said: In the Centre of Immensities.

It will be interesting to see whether the brightness has now peaked. If previous outbursts are anything to go by, it may have. But we’ll see! Novae and their much rarer cousins, recurrent novae, can really keep me up late at night (it’s now 2:55am here)!

How the Woke Cancelled Wumbus

June 1, 2021
Wum is for Wumbus, my high spouting whale who lives high on a hill.

Everyone knows How the Grinch Stole Christmas.

But have you heard How the Woke Cancelled Wumbus?

Among other Seussisms, “A Chinaman who eats with sticks” (from And to think that I saw it on Mulberry Street), was recently declared to be offensive.

On March 2nd 2021, Dr. Seuss Enterprises issued this statement:

Today, on Dr. Seuss’s Birthday, Dr. Seuss Enterprises celebrates reading and also our mission of supporting all children and families with messages of hope, inspiration, inclusion, and friendship.

We are committed to action.  To that end, Dr. Seuss Enterprises, working with a panel of experts, including educators, reviewed our catalog of titles and made the decision last year to cease publication and licensing of the following titles: And to Think That I Saw It on Mulberry StreetIf I Ran the Zoo, McElligot’s Pool, On Beyond Zebra!, Scrambled Eggs Super!, and The Cat’s Quizzer.  These books portray people in ways that are hurtful and wrong.

Ceasing sales of these books is only part of our commitment and our broader plan to ensure Dr. Seuss Enterprises’s catalog represents and supports all communities and families.

These books portray people in ways that are hurtful and wrong.

Hmm…

You have to admit though: that Wumbus high on the hill from On Beyond Zebra! looks pretty happy.

Land rights for gay whales anyone?

A Chinaman who eats with sticks… A big magician doing tricks…

No-one uses chopsticks anymore, right?

What about the “big” magician?

Should robust magicians everywhere suddenly be up in arms as they recall their traumatic childhood being force-read Dr Seuss?

In his recent article And then they came for ON BEYOND ZEBRA!, the American linguist John McWhorter said:

The book is not only entertaining but educational, in ways that a linguist like me especially values. It gently gets across the key fact that our letters only approximately reflect the language we actually speak. Note, for example, that there is no way to indicate with an isolated letter, or even a group of letters, the sound of u in put – if you don’t see it in the word itself, no other approximation works: oughooeueugh … see how nothing works? English has 26 letters to about 43 sounds, and Zebra introduces the idea, in its goofy way, that there could theoretically be more letters. 

But now we are to see the book as some kind of controversial contraband, and why? Specifically, on one page a man of no delineated race (and thus we would declare him “white,” I assume) is riding a kind of camel and has a mustache. A building in the background seems like, if anything (which it isn’t) some kind of pagoda. The man has the billowy pantaloons we would associate with an “Arab.”

I understand, formally, the idea that this picture signals that this is a Middle Easterner. However, I cannot be honest with myself and view it as a “stereotype.” In no way does this picture ridicule the man (or the animal), and in fact, the camel is a special kind (called a Spazzim) with elaborate horns that carry assorted objects which if anything make this man a mid-twentieth century homeowner.

SPAZZ is a letter I use to spell Spazzim, a beast who belongs to the Nazzim of Bazzim. Handy for travelling. That’s why he has ‘im.

I don’t know whether Dr. Seuss Enterprises felt pressure from within or without, but the action to which it has committed itself is an example of political correctness having reached dizzying new heights lately as the word woke has become part of our language.

Wokeness speaks to a keen awareness of social and racial injustice. We hear calls to “stay angry, stay woke”. The derivation is from African vernacular meaning that someone was sleeping but now is awake (“I was sleeping but now I’m woke“).

It’s not at all impossible to relate to such an awakening…

But with wokeness has come cancel culture.

Books from Dr. Seuss, along with other classics, are being cancelled.

Now, I lean pretty far left politically and ideologically. I’m a Green voting vegan atheist. I support freedom of speech, expression, and belief.

But it is arguably precisely these things that are under threat by cancel culture!

It reminds me of the Catholic Church’s Index Librorum Prohibitorum (index of forbidden books), the Nazi book burnings, and Ray Bradbury’s Sci-Fi story Fahrenheit 451.

To be fair, in the case of Dr Seuss, cancelled in practice just means: no longer being sold, not banned, but there are still books being banned, even if only in some countries.

Nevertheless, I think we have to resist a new index of forbidden books, no matter what form it takes.

Besides, if you did want to cultivate such an index, why on earth would you stop with modern classics?

Why not go after writings about (or by?) the vindictive, jealous, zealous god of the Old Testament, to name just one holy book?

Unless you think that burning witches or stoning adulterers or killing children if they’re disrespectful or slavery or drowning most of the world’s population are acceptable acts?

Or that damning people to Hell (New Testament) because they don’t utter the right magic words is okay?

No? Well, out with a bunch of books from the Bible then too!

But what counts as harm? What counts as injustice? What should be done about it?

If you look closely, you’ll notice that cancel culture is thoroughly anthropocentric.

How ordinary. How boring. How 20th century.

Not to diminish the importance of addressing the injustices still being done to people in various parts of the world, but why stop with human injustice? Why not upgrade racism to speciesism?

Floob-Boober-Bab-Boober-Bubs: they’re no good to eat, you can’t cook ’em like steaks, but they’re handy in crossing small oceans and lakes.

It’s easy to imagine a different group of outraged people applying Seuss book bans for treating other species, even if fictional or outlandish, as things to be used. And I don’t mean Thing One and Thing Two.

Those poor old mistreated Floob-Boober-Bab-Boober-Bubs. And don’t forget that the Nazzim only has the Spazzim because he’s handy for travelling. Or how about the udder (groan; dad joke) convenience of an Umbus?

UM is for Umbus, a sort of a cow with one head and one tail. But to milk this great cow you need more than one pail.

But Seussisms encourage a playfulness with language. And the corny humour never really gets old.

All Dr Seuss characters are essentially caricatures, including the chinaman with sticks, the Spazzim, and the magician.

There will always be someone to offend in this ultra-individualistic world we’ve created.

We have to stop worrying that something we write or say might be considered offensive to some group of people in the future and instead consider writings in their historical context.

That doesn’t mean that we should set out to hurt, to deliberately offend… Of course we shouldn’t…

And of course, we should stand against harm and injustice.

Obviously…

But what’s next: no Irish jokes? No jokes that start like: a priest, a rabbi, and a buddhist monk walk into a bar…

No question should be forbidden. No topic should be taboo.

Unless you think we’re special in some sense, except to one another, irrespective of any special capabilities we may have.

And yet…

We’re better than those others in some part of the world that is not ours. Right?

We’re smarter and superior to every other species. Right?

Wrong!

We have to reimagine ourselves as being a part of nature, the very nature that we seem so keen to distance ourselves from.

Not separate from nature. Not a special creation.

On this, especially, all holy books are misguided or misinterpreted. Usually both.

We are all biased beyond belief about one thing or another.

We are all flawed in some way.

Not one of us is perfect.

We need less judgement, misdirected anger, self-righteousness certainty, talk of those other people

We need more understanding, thoughtful conversation, tolerance of difference, kindness, forgiveness…

All easier said than done, I know…

Then again…

Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not.

(The Lorax, Dr Seuss)

Possible Nova in Sagittarius

April 6, 2021

Western Australian amateur astronomer Andrew Pearce has discovered a possible nova (PNV J17581670-2914490) in Sagittarius on April 4. At that time its visual magnitude was around 8.8.

Andrew reported in a message to Variable Stars South today that the object has been classified via spectroscopy as a classical nova.

The nova’s visual magnitude is currently around 8 or a little brighter. As always with these objects, it will be interesting to see how bright it gets.

Here is a finder chart suitable for binoculars (something of a challenge at the current brightness in 7x50s):

Rotating this finder chart a bit more than 90 degrees anti-clockwise will roughly match this image from Stellarium at around midnight AEST.

Zooming out gives more positional context:

Further out still shows even more familiar landmarks in Sagittarius and Scorpius.

I have yet to observe or image the nova but hope to do so over the next few days.

EDIT: After writing this I went out and had an initial look at the area. It was after midnight and the nova was in a good position from my backyard. I was just able to glimpse it in 7×50 binoculars but not well enough to make an estimate. So I took a few quick untracked shots of the region from which it appears that it’s probably around magnitude 7.8 (visual) which is consistent with what I glimpsed through binoculars.

I’ll keep an eye on it over the next few nights and hopefully take some better images.

EDIT: the weather did not improve early enough while the nova was still bright enough for me to observe.