The Enchanting Little Chamaeleon
4 Jan 2017
Not only are chameleons the dearest little creatures, they also have to be among the most fascinating, with few rivals when it comes to extraordinary anatomical features. A ballistic tongue that shoots out to snatch insects in a time-slicing 0.07 seconds. Telescopic-vision eyes that swivel and focus independently in domed turrets. A prehensile tail. Toes fused into mitten-like grippers. A skin flap circling the neck that it raises like an Elizabethan lace ruff. And most extraordinary of all, the ability to change colour with astonishing speed.
Contrary to common belief changing colour is not in response to a changing background; it is in fact a physiological reaction that’s mostly for communication. It’s colourful chameleon language, expressing things that affect it: courtship, competition, environmental stress.
It’s no wonder that when the Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman charted the southern skies in 1595–97, they added a chameleon to their constellations representing exotic animals. (Chameleons are particularly common in Madagascar, where the Dutch fleet stopped to rest and resupply in 1595 on its way to the East Indies, so they probably saw plenty of them there.)
On a globe of 1600, the Dutch cartographer Jodocus Hondius depicted the chameleon sticking out its tongue to catch the fly. Three years later, Johann Bayer in his Uranometria showed the chameleon in the same pose yet evidently failed to appreciate what the unnamed insect was supposed to be – he depicted it not as a fly but a bee and named it Apis.
Two hundred years later, in his Uranographia, Johann Bode (1801) depicted the chameleon ignoring the fly, which is still a bee, but which now lay above its head.
(In 1752 Nicolas-Louis de Lacaille renamed the bee Musca Australis, or the Southern Fly to distinguish it from the now discarded northern fly, Musca Borealis.)
In a 1917 paper entitled On Frederick de Houtman’s catalogue of southern stars, and the origin of the southern constellations, astronomer E. B. Knobel includes Chamaeleon’s stars from the extremely rare catalogue of the southern stars published by de Houtman in 1603 (which consisted of 303 stars). Knobel notes that, “…the right ascensions are too rough to allow of identification, but by plotting the whole catalogue in a map, and comparing the maps of the Uranomateria Argentia, it has been easy to identify nearly every star.”
How cool is it to read the record how de Houtman envisioned this fascinating little creature!
To see a chameleon at night is a rare treat… but luckily, there is always that other night chameleon – in the early hours of this morning I spent the loveliest time roaming around lovely Chamaeleon, admiring his handsome little form, and seeing some amazing objects, most of which were as elusive and shy as their terrestrial namesake.
Observations
16″ f4.5 Dobs; magnifications at 90x, 130x, 228x and 333x
I began with “the third in the tail” – where a notable deep sky object was discovered in 1999 –
Eta Chamaeleontis Cluster (or Mamajek 1)
RA 08 42 32.9 Dec -78 57 47 Mag – Size 43.4′
This is a very cool open cluster for a number of reasons: consisting of about 12 very young stars (8 millions years old) centered on eta Chamaeleontis, it’s the first open cluster discovered because of its member stars’ X-ray emission (from a deep ROSAT high-resolution imager observation), and the cluster is unusual because it appears isolated, without any dust or gas clouds that usually provide the material for star formation. The cluster lies very close to us, a mere 316 light years away.
It was lovely to see, although I was unable to tell which were the twelve cluster members. The brightest stars were gorgeous – sparkling white diamonds. (That tiny little galaxy visible in the DSS image, nested in among the stars, was invisible in the eyepiece.)
And then from sparklers to a dark nebula – one that was listed in Sandqvist’s Catalogue of Dark Nebulae, published in 1977.
Sandqvist 156 Dark Nebula
Dark nebulae are such mysterious objects, and this one was a very nice naked eye sight in this dark and transparent sky. Lying in a roughly north-south direction, it was a lovely void of nothingness. Lovely in the 10×50 binoculars, too – a well of inky darkness that faded to diffuse edges. Chamaeleon isn’t the starriest of constellations so I was surprised at how beautifully this dark nebula showed up against the background.
And talking of things dark, Chamaeleon contains a huge number of dark molecular clouds that are often referred to as the “Chamaeleon Cloud Complex”. Situation about 15 degrees below the galactic plane, it is accepted is one of the closest low mass star forming regions to the Sun with a distance of about 400 to 600 light years. Within these clouds are pre-main sequence star candidates, and low-mass T Tauri stars. The reflection nebula IC 2631 is the brightest nebula in the Chamaeleon Cloud Complex so I trotted over to have a look at it.
IC 2631 Bright Nebula
RA 11 09 52.8 Dec -76 36 51.5 Mag 9 Size –
Interestingly, IC 2631 is illuminated by the star HD 97300, one of the youngest — as well as most massive and brightest — stars in its neighbourhood. This region is full of star-making material, which is made evident by the presence of dark nebulae noticeable above and below IC 2631 in both images. In my telescope, the bright nebula showed a a small, bright, irregularly round glow surrounding the white 9th mag star, and it responded well to the UHC filter. The glow was very smooth and even with direct vision, with averted vision it appeared to fade around the periphery. The dark nebulae around it was evident from the lack of stars, but I couldn’t actually make much of it out.
E3 Globular Cluster
RA 09 20 59.3 Dec -77 16 57 Mag 11.4 Size –
E3 is a very difficult globular; it took me ages to find it and when I did (with averted vision) I only realised the extremely dim glow, just slightly brighter than the background sky, was indeed E3 because there aren’t any other extremely faint fuzzies in the vicinity. Once I found it, though, direct vision rendered it invisible, so I had to hold the cluster with averted vision. The cluster had an even surface brightness albeit extremely low. This was a real treat to find and see.
NGC 3195 Planetary Nebula
RA 10 09 21.0 Dec -80 51 34 Mag 11.6 Size 42″
A lovely bright little planetary nebula, it is a round, hazy grey mist of soft light. Its edges are soft and fuzzy. It responded really nicely to the OIII filter, revealing a slightly darker centre and a brightening to the south… it looked like a very small, very faded and lopsided Dumbell PN. It lies in a pretty star field sprinkled with lovely 10th and 11th mag stars.
NGC 2915 Galaxy I0
RA 09 26 12.2 Dec -76 37 37 Mag 12.7 Size 1.9′ x 1.0′
This galaxy showed as a dim, very slightly oval glow, elongated north-west to south-east. A smooth even glow with direct vision – averted vision revealed a slightly brighter centre. A lovely 7.8 mag star, gorgeously yellow, dominated the field.
NGC 3620 Galaxy
RA 11 16 05.0 Dec -76 13 01 Mag 13.3 Size 2.8′ x 1.1′
The galaxy appeared as a very faint oval glow elongated east-west. No brightening to a nucleus that I could see. A mag 14.5 star lies on the south side, a little west of the centre.
NGC 3149 Galaxy
RA 10 03 45.6 Dec -80 25 18 Mag 12.6 Size 2.0′ x 1.9′
This galaxy appeared as a very faint, small, round glow of even light. A good object to end on and give my eyes a rest from the straining required to see the objects in this constellation that seem to be as shy and elusive as their terrestrial namesake.
Copyright © Susan Young 2017