Centaurus A

NGC 5128, Caldwell 77

Image exposure:
90 minutes
Image field of view:
31.9 x 20 arcmin
Image date:

Astronomers now believe that NGC 5128 is actually the result of a relatively recent collision of two galaxies, with a giant elliptical galaxy and a smaller spiral galaxy in the early stages of merging!

The galaxy has the visual appearance of two separate objects: a bright circular halo and a warped encircling darker dust lane. This visual size can be as much as 25 x 20 arc-minutes. We now know that this object has a third major component: huge radio emission lobes, far bigger than the galaxy itself, from matter and energy emitted by the supermassive black hole in the very heart of the galaxy.

It is this radio astronomy discovery which earned it the name Centaurus A. It was the initial work by the Parkes Radio Observatory, here in New South Wales, which first defined the detailed structure of the radio lobes in the early 1960s

2018-05-19 The Parkes Radio Telescope, NSW
Image ©copyright R. Powell

What an astonishing jewel of the southern sky NGC 5128 is! Located in the constellation of Centaurus at a declination* of 43° S, it lies just 4° north of the huge globular cluster Omega Centauri, which will be the subject of my next post.

(*Declination is the celestial equivalent of latitude).

Astronomers living in Tasmania would see Centaurus A pass directly overhead; and here in Sydney at -34° S, we get a great view of it between March and June each year.

In the Northern Hemisphere it may be barely visible from a dark flat location as far north as about 40°.

It is such a beautiful galaxy, a mere 10-16 million light years away, equivalent to a distance of about 100 – 160 Milky Way diameters.

“Annals of the Deep Sky” (Vol 5) by Kanipe & Webb describes Centaurus A as an elliptical component which:

“takes on a soft milky texture, with the bisecting dark lane itself bisected on the SE end by a rift through which dimly shines the underlying galaxy. The edges of the lane appear slightly feathered and the entire field is suffused in a tenuous corona. A number of bright foreground stars punctuate the visible elliptical component, with one of the brightest situated 4.7 arc-minutes SSE of the nucleus, apparently in the halo (HD 116647), a magnitude 9 A7 giant.”

Telescope:Meade LX-90 200mm Schmidt-Cassegrain
(deforked); 2000 mm f/l @ f/10.
Optics:Astronomik light pollution filter.
Mount & Guiding:SkyWatcher EQ6-R Pro mount.
Imaging camera:ZWO ASI 071 MC cooled.

The Blind Astronomer

Cosmic Focus Observatory

34° South

Above us only sky….

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Images © Roger Powell

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ABOVE US ONLY SKY : amateur astronomy in australia


    1. We all have to make do with what is placed before us. The Sun is beginning to fizz and I’d love to see the aurora but it is rarely seen at my latitude and anyway I have no view of the southern horizon. 😐
      I guess you would have a better chance than me!

      Liked by 1 person

  1. Roger, I have learned so much from your postings. I can not begin to thank you..
    I can’t wait to read what comes next. Fran

    Liked by 1 person

    1. Hi Steve, thanks for your comment.

      Yes, so many people are getting attracted to astro-imaging now because the prices are within reach. We can routinely see fantastic images produced by amateur astronomers with low noise CMOS cameras.

      Of course, the big observatories, ground based and in space, have taken advantage of the advanced technologies too!


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