What's the best time to view or photograph the Moon?

Anyone who has ever owned a telescope has pointed it towards the Moon! 

We've had a lot and I mean a LOT of new astronomers who have received their ZWO S50 Pro smart telescopes from us over the last few weeks (with many more to arrive still) and one of the questions we're being asked at BINTEL by them is "I want to take a photo of the Full Moon. When is it and should I bother practicing before then?"

There's nothing like the Full Moon either through a telescope or just to get outside under on a clear night to enjoy with your eyes alone. 

However, this weekend is a good opportunity to enjoy observing the Moon as it gets towards its first quarter phase and in some ways, it's a more dramatic view than the phase that gets the werewolves all excited about. 

If you head outside in the middle of a bright sunny day, everything around you is evenly lit from the Sun. If you look around, you won't cast much of a shadow and objects around you won't either. This is because the Sun is likely almost right above you. Anyone flying over and looking down with a telescope would only see the top of your head, the tops of roofs, tops of mountains and so on. As the afternoon wears on, or if you'd walked outside earlier in the morning, the long shadows would present a more dramatic view and folks flying over would see the same.

It's the same when we view the Moon. Full Moon is effectively the middle of the Lunar "day" and while brightly illuminated, what you're seeing is the top of features. Earlier parts of the phase or "day" see long shadows that highlight mountains, the edges of craters, wide open Lunar plains and more. There's also the terminator which marks the edge of the daytime and nighttime on the Moon which is interesting to explore. 

A first quarter Moon taken by Ross Clark and posted to the BINTEL Society Facebook page a few years ago. 

Of course, the last quarter Moon phase is also wonderful time to observe the Moon and you'll see different Lunar features, but this will normally mean you're out under the night sky after midnight. 

The bottom line is that while there's no one right time to observe or image the Moon, the current phase is well worth exploring especially with a new ZWO Smart Telescope.

Galactic Winds

You might have seen us welcome to Alex McIntyre to the BINTEL team in this week's newsletter. Alex has just graduated with a degree in astronomy from The University of Sydney and it's a great time to let him explain his honour's thesis: 

"During honours year, my research focused on galactic winds – outflows of gas and dust expelled from the plane of a galaxy. These outflows can be launched by both intense periods of star formation and actively accreting black holes – my research focused on those driven by star formation.

Saying that these outflows are driven by star formation may be a bit of a misnomer however, as it is really supernovae which are the dominant driver of these outflows in star forming regions among other processes. These processes inject energy into a galaxy’s gas reservoirs, regulating future star formation which requires cool and dense gas to collapse under gravity. As such winds are an important process in the evolution of a galaxy.

As one can imagine winds driven by star formation are typically less energetic and harder to detect than their black hole driven counterparts. This has limited past work to studying winds launched from galaxies oriented edge-on, as the emission of a faint outflow is much easier to detect without the disc of the galaxy in the background. However, this both restricts our sample and denies us from directly observing the conditions in the disc from which the outflow was launched.

My project used the improved spectral resolution of the Hector Galaxy Survey’s new spectrograph mounted on the Anglo-Australian Telescope in Coonabarabran to observe galactic winds driven by star formation in face-on galaxies. As such the project served as both a test of Hector’s capabilities and the conditions which launch outflows in star-forming regions.

Using Hector, we were able to detect outflows in around 100 star-forming galaxies, with supernovae as their primary driver. We also observed a slight negative correlation between the velocity of an outflow and the rate of star formation in the region from which it was launched. Although slightly unintuitive at first this is a direct consequence of the feedback nature of galactic winds and the timescale needed to launch an outflow. As large-scale winds are primarily driven by supernovae, by the time they are launched from a region you would expect to see lower star formation, as a result of the energy injected by those very same supernovae*.

There were a few loose ends to tie up at the end of my honours year, which I have made sure not to mention here. Although I intend to pursue other fields of research for PhDs, which I am currently applying to, I’m excited to follow the updates from the Hector team and see where all the new data takes us.

* The most luminous stars have also reached the end of their life by this point, and the star formation rate of a region is determined by the Hα emission caused by ionisation from these massive stars."

White dwarf stars might also come in purple, pink and green

The average is still white though!

White dwarf stars refer to a stage of the life of a small to mid-sized star such as our Sun. In about 5 billion years, the Sun will begin to exhaust its nuclear fuel, swell into a red giant, possibly engulf the Earth and then shed the outer layers out into space as a planetary nebula and the remaining, dense body will become a white dwarf. Knowing how the Universe works, this is likely to happen on a Wednesday and will cause all sorts of traffic dramas on Sydney's M4 during the evening commute.

White dwarf stars no longer generate energy through nuclear fusion. Instead, they slowly radiate away the enormous amount of heat left over from the previous part of their life cycles. This take a long time. They've been described as an "end stage" of a star's life cycle but seeing they are formed when they're 10-ish billion years old and are expected to survive for maybe hundreds of trillions of years more as they cool down, our Sun will spend around 99.99% of its life as white dwarf before it slowly fades into a black dwarf. (BTW, we haven't found any black dwarf stars yet as the Universe is way too young for any to have been formed.)

Planetary nebulae are a favourite target for both visual astronomers and astrophotographers. 

The first stars of these types discovered were white in colour, but why should they be? After all, stars come in all sorts of colours. This was the very question that researchers from the University of Warwick asked.

The answer, according to new research from the University of Warwick, is "no." Published in the journal RAS Techniques and Instruments, the new study shows that if we could view them up close, certain white dwarf stars would shine in colors such as green, pink, cyan, yellow and purple.

Various colours of white dwarf stars. Image via: Mark Hollands/University of Warwick.

“Most stars, including most white dwarfs, behave like ‘perfect radiators,’ so their colour is set almost entirely by temperature. But nobody had really looked into what else might be possible for white dwarfs,” said Dr Mark Hollands, Warwick Prize Fellow in the Astronomy and Astrophysics Group, University of Warwick, who led the work. “It turns out these incredibly dense stars can produce colours nobody expected, and some of them genuinely surprised me." 

This white dwarf, WDJ1330+6435 has a ghostly green appearance due to sodium that's fallen into its atmosphere. Illustration via Mark A Garlick/University of Warwick

Even small trace amounts of various elements in the star's dense atmosphere can alter how these small dense stars would appear. Running the white dwarfs' spectra through a model of human vision, the team was able to simulate how they would appear to a much closer human observer. Even so, the colours seemed to appear to fall into several groups. 

Are astronomers going to rename White Dwarf stars to something else?

Not at this stage, although there they join many other astronomical objects that have an asterisk after their names saying, "there's more to this than we originally thought."

Read more here.

Pieces of the mirror for the largest telescope in the world has arrived in Chile packed in more than 500 boxes

We're pretty keen on big telescopes here at BINTEL!

The massive ELT in Chile is working towards completion, and we've reported on it before several times such as in this article. 

An illustration of how the ELT main mirror will appear. Image via: ESO

The main observatory building is well underway and now more than half the 798 segments that will make up its 39.2m diameter main mirror have now arrived in Chile. These have gradually been gathered since 2024. 

The mirror on the ELT gets recoated much like how the Sydney Harbour Bridge is repainted, bit by bit.

Large telescopes, like the AAT in Siding Spring in NSW, need to have their main mirrors removed from time to time to be recoated. Rather than removing the entire mirror and performing this recoating all at once, ESO has produced some 931 mirror segments. The team at the observatory in Chile will remove 2 segments a day, replace them with spare segments and then send them off to recoating. This will need to be done every day for the entire operational life of the ELT but also means the telescope will not need to stop observing while the mirrors are recoated. 

When completed, this will be the world's largest telescope, with science operations expected to begin in 2030. 

You can read more about this at the ESO site here.

Cheers,

Earl White

BINTEL

17th Oct 2026