Sand and Stars

Vela’s Spectacular SNR


Image credit ESO
16 April 2018

Supernova remnants! Not only do I find it dumbfounding to look at the tattered remains of a massive star that ended its life in a cataclysmic explosion thousands of years ago, but I also find that nothing connects me more to the immensity of the universe than standing here on our little rocky planet, looking at star stuff being ejected into the interstellar medium, and thinking that my own atoms were forged in the hearts of just such exploding stars.

I have spent the last couple of nights rummaging around in the area of the sky that contains the Vela Supernova remnant – and, as is so often in astronomy, there is a lot more here than at first meets the eye!

The Vela SNR is the spectacular showpiece of the region – the remains of a star that blew itself to smithereens around 11,000 years ago – but small slews of the telescope bring a treasure trove of open clusters, bright nebulae, dark nebulae, beautiful planetary nebulae, double and triple stars… it’s a fascinating region of space. I only realised exactly how full of goodies it is when I annotated this ESO image of the region (and it doesn’t by any means contain all the objects):


The  visible filaments of the supernova remnant are the decidedly filament-looking sections in the image sweeping from close to the star d Velorum up and around e Velorum, as well as the rich feathery strands sweeping downwards from between the two stars
The  visible filaments of the supernova remnant are the decidedly filament-looking sections in the centre of the image, sweeping from close to the star d Velorum up and around e Velorum, as well as the rich feathery strands sweeping downwards from between the two stars

Observing this spectacular SNR

16″ f/5 Dobs at magnifications of  40x, 70x, 150x, 228x and 333x 

An OIII filter is an absolute must while observing the Vela supernova remnant; without the filter, the 16” failed to show anything but maybe a slight hint of a filament here and there with averted vision (but more likely it was simply wishful thinking). But with the OIII filter and at 40x magnification, it was remarkable. The supernova’s remnants show as great curlicues of ghostly, almost insubstantial glowing nebulosity that sprawls across numerous eyepiece fields of view. Averted vision helps, and when what you’re looking at is very ethereal, you need all the help you can get.

There are numerous sinuous filaments of different proportions, and I tried to work my way back along the individual filaments in a bid to capture the next, but the complex, fractured appearance of the vaporous strands made it a vain attempt – although it certainly was a grand way to appreciate the vastness of the sprawling complex. And there are also a number of chunky sections, and some particularly wraith-like plumes of nebulosity here and there; all-in-all… stupendous!

NGC 2736 The Pencil Nebula

RA 09 00 18.0   Dec -45 57 00   Size 20′x3′

Image credit ESO
The Pencil Nebula. Image credit ESO

The Pencil Nebula – or Herschel’s Ray – is an outlying wisp of the Vela supernova remnant, almost the only sign of the eastern part of this vast bubble of expanding shock wave, and certainly the brightest. It is a stunning sight with the OIII filter; a long and narrow shard of bright nebulosity that runs NNE-SSW. The entire nebula appears streaky and very complex. It is brightest along its northern two thirds, gradually growing both dimmer and more diffuse until disappearing into the dark sky. Its eastern flank is pretty distinct and well-defined, while its western flank dissolves into a fine, feathery tangle of filaments. A pretty pair of stars – roughly mag 9 and 10 – lie along the eastern flank and four roughly mag 12 foreground stars look as if they are embedded in the nebulosity. It really is a grand sight.

I then meandered around some of the Gum nebulae in the vicinity:

Gum 23 Bright Nebula

RA 08 59 30.0   Dec -47 27 00   Size 25′x20′

DSS image
Gum 23. DSS image

With the OIII filter, this nebula appears as a pretty bright but very small, irregularly oval-ish glow of nebulosity. There is a hint of a very faint haziness to the east, separated from the brighter section by a patch of formless darkness.

Gum 25 Bright Nebula

RA 09 02 24.0   Dec -48 42 00   Size 7′x6′

DSS image
Gum 25. DSS image

With the OIII filter, this nebula appears as a roundish and pretty faint glow of haziness, and although faint, it did show some unevenness in its glow. It surrounds a roughly 10 mag star, and has a few other fainter stars that formed to my eye a rough Norma asterism.

Gum 20 Bright Nebula

RA 08 59 00.0   Dec −43 44 10   Size –

DSS image
Gum 20. DSS image

With the OIII filter, this nebula appears as a minute speck of glowing nebulosity, looking like a tiny droplet of moonlight glowing against the rich background of stars with a few very, very faint hints of nebulosity to the east.


Gum 19 Bright Nebula

RA 08 56 28   Dec -43 05 58   Size 2′x2′

Image credit ESO
Gum 19. Image credit ESO

The breathtakingly beautiful image notwithstanding, this nebula appeared as very small, a mere speck of glowing light. I found it by blinking with the OIII filter.

Gum 15 Bright Nebula

RA 08 44 48   Dec -41 20 00   Size 20′x15′

Collinder 197 – Open Cluster

RA 08 44 40   Dec -41 17 00   Mag 6.6   Size 25

DSS image
Gum 15 & Collinder 197. DSS image

The open cluster is a loose collection of stars of mixed magnitude stars lying scattered around in a rich field. The cluster is unusual in that it has two distinct sections – the northern section is far richer in stars that form a boxy shape. The southern section has fewer stars gathered in a more circular shape. The cluster lies embedded in the western shores of Gum 15, which, seen with the OIII filter, shows as a largish, roundish but very faint nebulosity. It appears marginally brighter on the north-eastern side and has a nice sprinkling of foreground stars sprinkled over it. I looked for, but couldn’t pick up, the minute splinter of dark nebula SL 2.

Gum 14 Bright Nebula

RA 08 44 48   Dec -41 20 00   Size 20′x15′

DSS image
Gum 14. DSS image

This huge nebula is very faint and I could only see patchy splotches of dim and hazy nebulosity here and there around what I took to be its perimeter. Although both the lovely open cluster, Ru 64, and the small tight open cluster, Pismis 5, appear to be embedded in the nebulosity I could find no sign of nebulosity around or within either of them when I looked at them. However, one little daub of bright nebulosity showed up beautifully…

Ruprecht 64 Open Cluster

RA 08 37 19.92   Dec -40 09 00   Mag –   Size 70

DSS image
Ruprecht 64 . DSS image

This is a lovely wide field open cluster – a loose sprawl of stars of mixed magnitude with the brighter members forming a gorgeous cascade across the centre. There are some pretty strings, loops and chains of fainter stars sprinkled around the cluster and standing out nicely against the rich background field. No sign in or around the cluster of Gum 14’s nebulosity in which the cluster lies. 

Pismis 5 Open Cluster

RA 08 37 39.0   Dec -39 34 38   Mag 9.9   Size 2

DSS image
Pismis 5. DSS image

This little cluster appears as a small and somewhat faint cluster of about 10 stars. The cluster displays two attractive little pairings stars – one pair in the centre, the other to the south – along with a tiny triangle on the northwestern edge, as well as a tiny bow of three stars on the eastern edge. No sign in or around the cluster of Gum 14’s nebulosity in which the cluster lies. 

Trumpler 10  Open Cluster

RA 08 47 45.0   Dec -42 30 00   Mag 5.0   Size 30′

DSS image
Trumpler 10. DSS image

This open cluster is a loose, sprawling and generous gathering of mixed magnitude stars. The stars form some pretty pairings, trios and little collections of stars. There is no distinct periphery – the stars simply blend into the rich background of stars.

Pismis 8 Open Cluster

RA 08 41 35.0   Dec -46 16 18   Mag 9.5   Size 3

DSS image
Pismis 8. DSS image

This is a pretty little cluster; one of those small ones that show as a soft misty glow of starlight with small but bright little stars resolved across it. The lucida lies at the southeastern edge of the cluster, showing nicely against the glow and glints.

Markarian 18 Open Cluster

RA 09 00 31   Dec -48 59 06   Mag 7.8   Size 5′

DSS image
Markarian 18. DSS image

This is a small grouping of about a dozen stars that are grouped around three roughly mag 10 stars. An outlying pair of brightish stars to the southwest point at the cluster, reminding me of the Southern Cross’ two pointers.

vdB-Ha 34 Open Cluster

RA 08 31 12   Dec -44 30 00   Mag –   Size 25′

DSS image
vdB-Ha 34. DSS image

This is a surprisingly pretty little cluster – about a dozen or so mag 9 to mag 11 stars scattered in a NE-SW stream. About two or so dozen fainter stars are scattered along the western flank of the stream of brighter stars. The cluster stands out nicely against the background stars, although it was impossible to tell which of the fainter stars were cluster members.

K2-15 Planetary Nebula

RA 08 48 40.7   Dec -42 54 05   Mag 13.4 CS 11.3v Diam 185″

K2-15. DSS image

Barely perceptible without a filter (one only sees it after identifying it with the filter), it responds well to the OIII filter, appearing as fairly large, rather faint but very even nebulous glow. It is an unusual squarish-shape. No colour that I could see, and no sign of its central star. A line of roughly mag 12 stars stretch in an east-west direction across its centre, and there is a close pair of also roughly mag 12 stars on its northern edge.

Wray 16-16 Planetary Nebula

RA 08 11 31.9   Dec -48 43 15   Mag 12.4   CS 16.9   Size 44″

Wray 16-16

This planetary nebula lies in a lovely field of bright stars and is itself situated in a gorgeous string of stars that form a question mark asterism, which is a lucky thing for I otherwise would never have found it. Blinking with the OIII filter and averted vision helped identify it. It appeared stellar, faint; a smooth little stellar droplet of glowing luminosity. No sight of its central star.  

What a wonderful night it was cruising around this highly complex region! There is a heap more objects to observe… but that for another night… another blog.

Copyright © Susan Young 2018