Readers’ wildlife photos

Reader Tim Anderson from Oz sends astronomy, landscape and animal photos; his captions are indented.

Here a two astronomical images I have made recently. First is a globular cluster, Omega Centauri (NGC 5139). This is easily visible to the naked eye, as it is the brightest such object in the sky and contains about five million stars. This image was captured using a colour CCD camera.
Second is the Tarantula Nebula (NGC 2070), which is a very active star-forming region embedded in the Large Magellanic Cloud. This is another composite LRGB image with the L (for luminance) channel provided by imaging “Hydrogen Alpha” emissions given off by ionised hydrogen atoms in the gas clouds being excited by the intense stellar radiation. Unfortunately, it was a very hazy night, hence the haloes round the bright stars.
I found this fella (a short-beaked echidna, Tachyglossus aculeatus) waddling across a country road near Reid’s Flat in New South Wales:
Here is a juvenile nankeen night-heron (Nycticorax caledonicus) putting a tortoise in its place. This bird is common in Australian wetlands.
And “Sunset in Cowra, New South Wales”, sent yesterday:
I think this probably doesn’t count as wildlife, but this was the view down my street this evening.

15 Comments

  1. Posted May 3, 2017 at 7:49 am | Permalink

    Nice pictures, thanks for sharing. 🙂

  2. ThyroidPlanet
    Posted May 3, 2017 at 7:50 am | Permalink

    YOWZA!

  3. Posted May 3, 2017 at 8:08 am | Permalink

    Very nice pictures.

  4. Posted May 3, 2017 at 8:11 am | Permalink

    Great pictures! Can you tell us more about the astronomy pictures, how you take them?

    • Posted May 3, 2017 at 8:47 am | Permalink

      August43, thanks for asking.

      The pic of Alpha Centauri was taken with a colour astronomical camera (an Atik 314L+) through a 110mm refractor telescope. It is made up from thirty 120-second exposures stacked on top of each other.

      The pic of the Tarantula Nebula was taken with a monochrome camera (an Atik 420). To get a colour picture with a monochrome camera, you successively take pictures with a red filter (which allows only red light through), then pictures with a green filter, then with a blue filter. Then finally you take a set of pictures using an “Ha” filter (which let’s through only the light emitted by excited hydrogen atoms).

      After you have collected all the pictures (in this case, thirty exposures of 60 seconds for each filter), you then stack all the exposures together (each filter stack is colored appropriately), you get a colour I age.

      Unfortunately, I took these images on a very hazy night – the local farmers are burning off their fields prior to planting the new wheat crop – so the final image is a bit foggy.

      • Don McCrady
        Posted May 3, 2017 at 11:54 am | Permalink

        Great pictures Tim. For the Tarantula, I was wondering why the colours are so muted. Did you use the H-alpha at 100% luminance? You might try dialing it back to let the RGB colours show through better.

        Omega Centuri is spectacular!

      • Posted May 9, 2017 at 1:10 am | Permalink

        The pictures do actually look amazing.

  5. Heather Hastie
    Posted May 3, 2017 at 8:38 am | Permalink

    Gorgeous pics!

  6. Michael Fisher
    Posted May 3, 2017 at 9:21 am | Permalink

    Omega Centauri must be a very interesting cluster to live in – according to Wiki the stars are estimated to average only 0.1 light years away from each other. I’ve often thought that such globular clusters might be just the sort of place where interstellar civilisations are most likely* to arise

    * Except, now that I look, it seems that the ‘metallicity’ of clusters is low, hence few rocky planets & maybe too much solar radiation about the place

    • Posted May 3, 2017 at 9:34 am | Permalink

      At an average of 0.1 light-year separation between the stars in that cluster, any carbon-based life would get fritzed in no time flat.

      • Michael Fisher
        Posted May 3, 2017 at 10:04 am | Permalink

        @Tim

        I wondered about that as you can see from my original comment, but I think the lack of rocky planets is the bigger barrier to a tech civilisation.

        I don’t have the expertise to know how evolution might play out in a high radiation alien environment, but we know from how quickly life got going on Earth, that nature seems to embrace extreme conditions – presumably stellar radiation isn’t a problem for metabolising carbon-based chemistry in an ocean or pool protected by a magnetic field. Perhaps there are more robust versions of DNA-type molecules that are optimised to repair more efficiently [but not too efficiently!] than our own?

        Some Earthly critter examples of lethal dose of ionising radiation in Grays [Gy]:

        Mammal, Homo sapiens sapiens, 10 Gy
        Eutardigrade, Milnesium tardigradum, 5,000
        Bacteria, Deinococcus radiodurans, 15,000
        Archaea, Thermococcus gammatolerans, 30,000

        • Posted May 3, 2017 at 10:36 am | Permalink

          Radiation would not really a problem. 0.1 light years is still 10,000 times the distance we are from the Sun.

          A bigger problem would be whether planetary orbits are long-term stable, given gravitational perturbations by other stars.

  7. Mark R.
    Posted May 3, 2017 at 3:10 pm | Permalink

    Really cool pics. I always enjoy your astronomy photos.

    Just curious, is there a distinction in Australia between a tortoise and a turtle? In the US, the heron would be putting a turtle in its place. We tend to think of turtles as aquatic and tortoises terrestrial, though it’s not a black and white distinction.

    • Posted May 3, 2017 at 6:01 pm | Permalink

      I think the distinction here is that turtles are marine and tortoises live in fresh water,

  8. Posted May 3, 2017 at 5:27 pm | Permalink

    I had Omega Centauri (NGC 5139) screen printed onto a t shirt, the above shot would have been a better template. The sunset is a ripper and the bird and tortoise is a bit of humour. Enjoyed all and thanks.


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