Two hundred years ago: 29th April 1826. A night of discovery from Parramatta 

There's a "fair" amount of light pollution in the middle of Parramatta, about 20km west of Sydney, in 2026. However, wind the clock back 200 years to this time of the year to a  remarkable evening of discovery at Parramatta Observatory by astronomer James Dunlop. 

First of all he observed a new nebula (NGC 4945), and then some 30 minutes later another patch of cloud in the sky known as NGC 5128. We now know that both of these discoveries are not patches of patches of star-forming gases, but rather massive galaxies millions of light years away from the Milky Way. 

James Dunlop’s sketch of NGC 5128 (Figure 20) from 1828. Credit: Dunlop/Robertson et al. 2010.

At the time these were the only two galaxies in the far southern sky recorded by astronomers aside from the Large and Small Magellanic Clouds. 

Here's a more modern take on NGC 5128 taken by Chi Chan and with a Celestron EdgeHD 9.25 Telescope and a ZWO ASI286MM camera.

NGC 5128 is the 5th brightest galaxy in the night sky and is great for both astro imagers and visual observers, with its central dark lane being visible even in fairly small telescopes. 

Where can I see NGC 5128 at the moment?

Just like James Dunlop spotted this lovely galaxy 200 years ago in our Sydney autumn, you'll be able to see NGC 5128 in the south eastern sky.

The view from Sydney around 7.30pm showing NGC 5128 (labelled C 77 in this image) near the Southern Cross. It will rise higher in the night sky as evening progresses. 

You can spot it as a small, fuzzy patch with binoculars. Larger telescopes such as a 6" Dobsonian will show the dark central band which is the result of galactic mergers.

Why are comets green?

And why their tails are not.

Glenn Pickford posted his image of Comet Panstarrs to the BINTEL Society Facebook group. Check out his post here.

There are some simply beautiful images being captured this week of Comet C/2025 R3 (PANSTARRS) or simply Comet Panstarrs as it's being called. This is an Oort Cloud comet, meaning a ball of loosely bound dust, gases, water and other material is making what could be its first trip into the inner Solar System from a vast region that extends into interstellar space. 

You might see media reports about it being a "once in a lifetime experience" and that's true of this particular comet. Its orbital period seems to be around 170,000 years and I doubt any of us will be around to see it again, no matter how good your diet and skin care routine is.

However, comets like these are visible once every few years and we were lucky enough last year to even have two visible in the same part of the sky at once!

Binoculars are ideal for looking at comets and the BINTEL Society is a handy way to pick up tips and ideas for photographing them as well. 

One question that does pop up is "Why are the heads of some comets green?"

In fact up until a few years ago, we didn't know why! It's a fascinating story about  Solar radiation breaking up molecules that it only just created. These dicarbon molecules glow bright green, but themselves don't hang around that long and are soon broken up. They don't have time to fall away from the head or nucleus of a comet and spread into space as the comet's tail. They fade away before they have time to make it that far. That's why the region close to the comet's nucleus might appear green but the tail won't be.

You can read more about how the team from the University of New South Wales discovered this in a BINTEL blog article from a couple of years ago.  

One thing to remember when observing comets is that while these green colours are often easily captured in photos, you won't see them with your eyes when looking at them through a telescope or binoculars.

New evidence of organic materials found on Mars

Seven organic molecules detected for the first time on Mars

Mars rover, Curiosity, taking a selfie in 2022. Image via NASA/JPL-Caltech/MSSS

NASA announced recently another set of findings that point toward the possibility of past life existing on the surface of Mars. After drilling into a rock called "Mary Anning 3”, named after an English fossil collector and , scientists found the most diverse collection of organic molecules ever found on Mars.

The rocks on the surface of Mars where Curiosity collected samples in October 2020. Image via NASA/JPL-Caltech/MSSS

Twenty-one carbon-containing molecules were identified in the samples, seven of them were detected for the first time on Mars. 

It should be pointed out that organic molecules or "organics" are not themselves direct signs of life. They are the "stuff" that life is made up of or the results of life processes. They can also be produced by non-biological reactions and processes. At the moment, we have no direct way of knowing what led to the growing list of organic molecules being found on Mars. Organics are found elsewhere in the Solar System and in gas clouds in deep space.

“That detection is pretty profound because these structures can be chemical precursors to more complex nitrogen-bearing molecules,” said the paper’s lead author, Amy Williams of the University of Florida in Gainesville. “Nitrogen heterorcycles have never been found before on the Martian surface or confirmed in Martian meteorites.”

“This is Curiosity and our team at their best. It took dozens of scientists and engineers to locate this site, drill the sample, and make these discoveries with our awesome robot,” said the mission’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. “This collection of organic molecules once again increases the prospect that Mars offered a home for life in the ancient past.

What does this mean for the chances of one day confirming life on Mars?

These results add to the growing number of organics and other chemicals found on Mars that might have been produced by past life. They've been collected from regions that were once covered by water as indicated by the local geology. 

The issue is that no hardware currently on the surface of Mars has sufficient onboard technology to carry out the sorts of tests to definitely confirm that once was life was indeed present at these sites. It's going to take either "boots" on the ground where specialist astronauts can carry out the sorts of experiments needed, or sufficient samples returned to Earth. 

Until then these discoveries offer tantalising hints of what might have existed on the Red Planet. 

You can read more at the NASA site here.

Cheers,

Earl White

BINTEL

6th May 2026