Celestial hemisphere:  Southern  ·  Constellation: Lupus (Lup)  ·  Contains:  HD127139  ·  HD127153  ·  HD127177  ·  HD127566  ·  HD127627  ·  HD127731  ·  HD127812  ·  NGC 5643
NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill
NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill

NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM)

NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill
NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill

NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM)

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Description

NGC 5643 is a beautifull intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years. It has an active galactic nucleus and is a type II Seyfert galaxy, with two well-defined, symmetric arms. In the circumnuclear region are other dust spirals, but the two main dust arms are wider. The galaxy is seen nearly face on, at an inclination of ∼ 27°. The apparent diameter of the object is only 4′.6 × 4′.0 so I knew it would be small in the FOV. At the distance it must have a diameter of ~ 65,000 light years, so about 2/3 the size of the Milky Way. At a Declination of -44° it is not imaged by many and I only found 8 examples on AstroBin. However, at my latitude of 33°S, it gets to nearly overhead. Nevertheless, the object is quite small which limits the resolution of detail. I provided a zoomed in view (Revision B), accessible via the mouse-over which makes it easier to see the detail which was resolved. Just above the centre of the galaxy and outside the first spiral arm at 11 o'clock is a yellowish linear feature, which is actually a distant galaxy behind NGC 5643. It can be more readily seen the the extant Hubble Image which puts the fact that it is a distant galaxy beyond doubt. The strong yellow colour is likely due to the attenuation of the light from said galaxy coming through the dust in the ISM and the foreground galaxy. There is some evidence of Vorontsov-Velyaminov rows, with the 3 sections of the spiral arms showing distinctly straight sections.

Also visible in revision B towards the bottom of the image at about 7 o'clock, is a fascinating pair of interacting galaxies that would have been worthy additions to Arp's Atlas of Peculiar Galaxies. 

A particulary fortuitous run of clear skies, had me able to gather the data for this in a week and it helps having 10 hours of darkness now. With the Moon waxing I had quite a bit of time  to capture the subtle Ha (11hrs), before getting on to the LRGB (17 hours) once the Moon set. The Ha data showed a large number of small clumps dotted around the galactic arms and I used the Ha continuum mapping process to incoporate the Ha data. I took some care to not have the Ha red being too garish and I think this is better, as in more subtle, than some of my  previous galaxy images.
There is a large amount of interstellar medium (ISM) visible in the image and it was even more apparent in the starless image. I did some research which told me that the Constellation of Lupus is well known for the amount of ISM present there.  "The Lupus 3 star forming region lies within the constellation of Scorpius (The Scorpion), only 600 light-years away from Earth. It is part of a larger complex called the Lupus Clouds, which takes its name from the adjacent constellation of Lupus (The Wolf constellation). The clouds resemble smoke billowing across a background of millions of stars, but in fact these clouds are a dark nebula." - ESO. "Cosmic dust snakes and starbirth in Lupus 3." ScienceDaily. ScienceDaily, 31 January 2018. <www.sciencedaily.com/releases/2018/01/180131090311.htm&gt;.

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  • Final
    NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill
    Original
    NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill
    B

B

Description: This is a cropped in view to show the galaxy detail

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NGC 5643, a Spiral Galaxy in Lupus amid the interstellar medium (ISM), Niall MacNeill