Archive for the ‘Astronomy, Science’ Category

Nova Interruptus

June 23, 2017

nova_interruptus

I like to call this wide field (12 x 8 degrees) image, taken with a Canon 1100D (ISO 100, f2.0 100mm), nova interruptus. 🙂

The red arrow points to ASASSN-17gk (shown in inset), an 11th magnitude nova in Centaurus I observed on May 21. It also shows the trail left by a passenger airliner as it moved from top left to lower right during the one minute exposure, with tree-tops at bottom.

ASASSN-17gk visual band

The signal to noise ratio wasn’t high enough to get a good value and error for the nova’s magnitude via DSLR photometry, so I didn’t submit an observation. The light curve at left shows observations made by others and the polynomial fit below highlights the rough shape of the light curve.

ASASSN-17gk visual polyfit

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HD 148703

June 12, 2017

A request for observations by astronomers at the University of Wroclaw in Poland was announced by AAVSO on June 8.

The bright (magnitude 4.23 V) long period eclipsing binary HD 148703 (aka N Sco, HR 6143) is expected to undergo primary and secondary eclipses on June 11 and 14 each lasting around 20 hours.

The brightness and requested precision of 0.01 or better makes this an ideal candidate for wide field DSLR photometry.

I’ve taken pre-eclipse images but cloud prevented me from imaging the primary eclipse. I’ll take further images over the next few days, hoping to record the secondary eclipse.

Update on novae in Sagittarius

December 11, 2016

It’s been a month since my last update on ASASSN-16ma and  TCP J18102829-2729590, mostly due to family commitments; my wife was out of town with her sick father, and looking after her mother, so I was busy keeping things going on the home front.

As can be seen below, both novae have been in decline for most of that time.

tcp-j18102829-2729590

asassn-16ma

ASASSN-16ma declining?

November 11, 2016

Poor weather prevented any observations last night but tonight the sky cleared after a late afternoon storm and I estimated the nova at magnitude 6.3.

asassn-16manov11

So, it’s been gradually declining for 3 days, but whether that continues remains to be seen.

ASASSN-16ma update

November 9, 2016

As mentioned in yesterday’s updated post (with finder chart), conditions last night were less than ideal, but when the clouds cleared enough, I estimated the nova’s magnitude at 6.1.

asassn-16manov10

 

Update on two novae in Sagittarius

November 7, 2016

Poor weather then being away for work for three days last week has kept me away from variable star observing since October 29. Last night (November 6) I observed TCP J18102829-2729590 and ASASSN-16ma again.

While the first is on the decline currently (around magnitude 9):

tcp-j18102829-2729590-lc-nov-7

On the other hand, I caught ASASSN-16ma on the rise. My October 29 observation gave a visual magnitude of 10.3 whereas last night it was 7.3. Several hours later others were recording it at around 6.5:

asassn-16manov-7

So, ASASSN-16ma has exceeded TCP J18102829-2729590’s maximum (so far) by around one magnitude. If this rate of increase continues, who knows, maybe it will reach naked eye visibility. Here’s hoping!

 

Musings on lecture by Vatican Astronomer

October 28, 2016
cq5dam-web-1280-1280
Vatican Observatory, Arizona (source: goo.gl/cl7EpF)

Jesuit priest and Vatican observatory director Brother Guy J. Consolmagno visited Adelaide in August and gave a public lecture at UniSA.

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Guy J. Consolmagno (source: goo.gl/Sxui6h)

I arrived early to have a meal at the Mawson Lakes hotel. Paul Curnow (ASSA vice president) and I spotted each other. He was at a table with a group of people, two of whom wore clerical collars, so I assumed one was Brother Guy. Paul invited me to eat with the group, a mixture of amateur astronomers (ASSA members) and Catholic church members, and in some cases, possibly both.

During dinner I asked Guy about the forthcoming southern edition of his book, Turn Left at Orion. He recently co-authored another book, Would you Baptize an Extraterrestrial? Whatever my pre-conceptions may have been, he seemed smart and witty, hard not to like.

His talk was titled The Heavens Proclaim: Astronomy and the Vatican after a now out of print book. It quickly became clear that he was a very good Science communicator (in 2014 he was recipient of the Carl Sagan Medal for excellence in education and public outreach) and a long-time practitioner of the Scientific Method. He also writes an interesting blog. The talk ranged widely from the Vatican Observatory‘s roots in the Gregorian Calendar reform of 1582 to the work of the Jesuit astronomers at the observatory’s current (and surprising!) location in Arizona.

A number of slides in the talk were devoted to Galileo. Guy admitted that while the whole sordid business was more nuanced than is sometimes realised, the church should not have gone after Galileo in the way it did. Contrast this to Mother Theresa who said she would have sided with the church over Galileo! It should of course be still further admitted that the fact that it took 350 years for the Catholic church to pardon Galileo (not until 1992, and assuming he needed pardoning at all!) of the charge of heresy should be more than a bit embarrassing to the Church. I don’t want to dwell on this here though.
Guy mentioned religion at various points during the talk, quoting scripture a handful of times, citing for example the number of occurrences of “star” in the Bible. He didn’t justify why he thought Christianity and the Catholic denomination in particular was the correct one out of all the possible religions (or none at all). Given the convictions of a substantial part of the audience, I suspect he didn’t feel the need to do so.
He wittily reversed the atheist quip about believing in only one less god than a monotheist, saying that he believed in only one more god than Richard Dawkins; not a valid move of course, but funny.

I wondered whether Guy’s view of the relationship between Science and Religion would align with the late evolutionary biologist Stephen J. Gould’s Non-overlapping Magesteria:

Here, I believe, lies the greatest strength and necessity of NOMA, the nonoverlapping magisteria of science and religion. NOMA permits—indeed enjoins—the prospect of respectful discourse, of constant input from both magisteria toward the common goal of wisdom. If human beings are anything special, we are the creatures that must ponder and talk. Pope John Paul II would surely point out to me that his magisterium has always recognized this distinction, for “in principio, erat verbum”—”In the beginning was the Word.”

In his talk, Guy said that Science brings him closer to God. According to his wikipedia page:

He believes in the need for science and religion to work alongside one another rather than as competing ideologies. In 2006, he said, “Religion needs science to keep it away from superstition and keep it close to reality, to protect it from creationism.”

The relationship Guy espouses seems more strongly aligned with Science than does NOMA, with a focus on preventing religion from going off the rails, yet still it’s clear (and not surprising since he’s a Jesuit priest) that for Guy, religion acts to inspire his relationship with Science.

Guy commented upon Georges Lemaître, the Belgian Catholic priest who published a paper in 1927 titled A homogeneous Universe of constant mass and growing radius accounting for the radial velocity of extragalactic nebulae, and later the idea of a “primeval atom”, making him the father of Big Bang theory. In the paper he proposed a value for the estimated rate of universal expansion subsequently confirmed by Edwin Hubble, now called the Hubble Constant. There’s an argument to be made that it should have been the Lemaître Constant after the less widely published Belgian scientist.

lemaitre

Georges Lemaître (source: goo.gl/BN6EKm)

Although Lemaître may have been sympathetic to the essence of NOMA, he helped to persuade Pope Pius XII to stop making proclamations about the relationship between science and religion, stating that there was neither a connection nor a contradiction between religion and his hypotheses.

During question time at the end of the talk, someone asked Guy how young people could be encouraged not to abandon religion as they learn more about Science. Guy responded by agreeing that adopting a scientific world view doesn’t mean abandoning religion, reiterating that Science brings him closer to God, and suggesting that an atheistic worldview was unnecessary and perhaps even a little further, at least to him and the questioner, not tasteful.

As an atheist and secular humanist, I obviously disagree with this viewpoint. It’s possible to retain a sense of wonder and a hunger for knowledge without the need for a deity.

Guy spoke about the fact that Lemaître understood the importance of allowing the data to speak, to provide evidence in support of (or not) an hypothesis.

In relation to the god hypothesis, that is all an atheist claims.

What I don’t understand is why the god hypothesis is different from any other. Is there supporting evidence for a deity of a particular kind, the god(s) of the Bible, for example? Shouldn’t the Scientific Method be applied here? Does Guy consider this valid? That’s the question I would ask if I spoke with him again, I think.

My only other criticism was the brief mention Guy made about how the Catholic church helps the poor, arguably not appropriate for a talk about astronomy, but not surprising when you accept that it was part lecture, part sermon. I’ve sat through (and given enough in my misguided past) sermons to know one when I hear one. I’ve written more about the relationship between the church and the poor elsewhere.

There’s no doubt that Brother Guy Consolmagno and the other Jesuit astronomers at the Vatican Observatory are doing good Science. In particular, Guy’s research explores connections between meteorites, asteroids, and the evolution of small solar system bodies and he employs the observatory’s 1.8 metre telescope to observe Kuiper Belt objects.

Of course, you need math, science, and a telescope or at least data from someone else’s telescope to do astronomy. You don’t need religion to do astronomy.

To borrow the title of the 2009 Intelligence Squared debate, “is the Catholic Church a force for a good in the world” insofar as astronomy is concerned? It would seem so, but in the end, I can’t help but feel that the Vatican Observatory and its astronomers stand in stark contrast to the Catholic church’s irresponsible prohibitions against contraception, the scandal of child abuse by clergy, and the extravagance of beatification.

Two novae in Sagittarius!

October 28, 2016

Since my last post I’ve made two more observations of TCP J18102829-2729590, on Oct 26 and 27. Mine are the larger purple data points. Fraser Farrell pointed out a nice recent Sky & Telescope News article about this nova.

tcp-j18102829-2729590-lc-oct-28

Another nova was discovered in Sagittarius on Oct 26: ASASSN-16ma. There are only a few observations of this one so far. Mine is at top right under the cross hairs.

asassn-16ktlcsep28

ASASSN-16ma is currently three magnitudes fainter than TCP J18102829-2729590, but the latter arrived on the scene first, after all.

The weather looks good for tonight and tomorrow so I hope to get some more observations in over the weekend.

Nova TCP J18102829-2729590 still on the rise

October 24, 2016

tcp-j18102829-2729590-lc-oct-25

Nova TCP J18102829-2729590 in Sagittarius is still on the rise although not at the same rate as a day or so ago. Early days though: these things are unpredictable.

The official AAVSO alert notice was posted overnight: https://www.aavso.org/aavso-alert-notice-560

I have ongoing alignment problems with my LX-90 8″ scope (16 years old) and they caused me enough grief last night that I couldn’t make a visual estimate before the nova was below my fence line. I’ll try again in the next day or two.

Nova in Sagittarius

October 23, 2016

Not far from one of my favourite Cepheid variables (W Sagittarii), a nova in Sagittarius was discovered 3 days ago (TCP J18102829-2729590) by Koichi Itagaki of Japan. It has risen from magnitude 11 to 8 in that time.

The plot below shows the 10 visual and Johnson V observations submitted so far to the AAVSO International Database:

tcp-j18102829-2729590-oct-23-lc

Two thirds of the visual observations are from Andrew Pearce in Western Australia. My single observation so far, made tonight, is under the cross hairs at upper right, with Andrew close on my heels. It’s always reassuring when two observations made close in time (less than an hour in this case) by different observers agree, within the limits of precision of the chosen method (visual estimation: approximately one tenth of a magnitude).

Many of my visual estimates of variable stars are made with 7×50 binoculars. Tonight I used my Meade LX-90 8″ telescope (magnification of 82x) because the nova is still too faint for my binoculars. There’s a beautiful asterism near the nova that makes the field hard to miss and makes for an enjoyable observation.

x16826ks

Last night I took images of the nova with the intention of carrying out wide field DSLR photometry, however there’s a star quite close to the nova. When combined with the amount of defocus normally used for DSLR photometry, separating the light from the two stars becomes impractical. So, I haven’t submitted an observation (untransformed) from that imaging run.

I’ll follow this object visually with interest for as long as the weather and my equipment allow.