Sand and Stars

The Illustrious Telescopium

Galileo’s telescope, which is preserved today at the Museo Galileo in Italy. Image credit:

25 Aug 2016

While waiting for my eyes to dark adapt, I was idly tracing out Telescopium’s faint and obscure shape in the sky, thinking about this obscure little constellation: no-one has placed a more important constellation among the stars than Nicolas Louis de Lacaille did when he put a telescope up there.

We owe the telescope the most illustrious position in the sky, bar none. You only have to look at the photo of Galileo’s telescope to agree that it is undoubtedly the most important piece of equipment in astronomy.  Without telescopes mankind wouldn’t have even been able to imagine, never mind begin to understand, the true nature of the universe. Without telescopes, we astronomer types couldn’t be voyaging to the stars every clear night. Without telescopes we’d be impoverished as astronomers, as human beings, as citizens of this astonishing universe.

Truly, Telescopium should be the patron constellation of astronomers… calling for strange rites, maybe the odd sacrifice or two, at culmination.

The pattern of stars that made up Lacaille’s Telescopium represented the great astronomical refractor at the Paris Observatory – known as an aerial telescope because in common with other large refractors of the day, it had an exceptionally long tube (to combat chromatic aberration) and was suspended from a mast by ropes and pulleys.

Lacaille’s telescope was equally long… it covered 40 degrees of the night sky in order to incorporate the aerial telescope’s great length – stretching out northwards between Sagittarius and Scorpius. He “borrowed” stars from nearby constellations, including Sagittarius, Scorpius, Ophiucus and Corona Australis.

This is Lacaille’s original depiction of Telescopium, published in the Atlas Céleste of Jean Fortin

But modern astronomers returned the stars to their rightful owners by hacking off the top of the telescope’s tube and mounting so that it is now restricted to a rectangular area of sky south of Sagittarius and Corona Australis.

Thus, Lacaille’s Beta Telescopii (positioned in the pulley at the top of the mast) became Eta Sagittarii. His Gamma Telescopii (in the upper part of the refractor’s tube) became G Scorpii. And his Theta Telescopii (which marked the telescope’s objective lens) became 45 Ophiuchi.

I like the hacked down version because to me the constellation now represents Lacaille’s 8x, 26-inch-long refractor with a ½-inch objective. I am beyond flabbergasted at what he saw through his tiny refractor… and the few treasures in this little constellation that contains no stars brighter than fourth magnitude, seems a most fitting memorial to this extraordinary astronomer.

So I spent a happy while cruising around Lacaille’s telescope with my telescope. 


10″ f/5 Dobs; 90x, 144x and 208x 


NGC 6584 – Globular Cluster

RA 18 18 37.7   Dec -52 12 54   Mag 7.9   Size 6.6′

DSS image
NGC 6584. DSS image

Telescopium has an eyepiece… this delightful little globular cluster lying there beside the telescope. It’s a delightful little 7.9 mag chap lying just east of an arc of three approximately 11th mag stars. At low power, lovely: a bright round, very slightly powdered glow that gradually brightens to a condensed core. Beautiful against the busy star field; but loveliest of this globular is what I find unutterably beautiful with all globulars – the unresolved starlight: the misty gossamer glow of thousands upon thousands of unresolved stars.

At higher powers the globular shyly gave up some resolved stars around the periphery that radiated in all directions from the unresolved core, one very faint wavering string radiating north. The core itself became ever so slightly not-round, a little scattered-looking, if a small unresolved glow can become scattered-looking.

The arc of three 11 mag stars enhance the western part of the globular, making it appear larger than it is. All in all, a lovely globular; a lovely eyepiece for Telescopium.

NGC 6868 – Galaxy 

RA 20 09 53.6   Dec -48 22 44   Mag 10.7   Size 3.5′ x 2.8′

NGC 6870 – Galaxy 

RA 20 10 11.1   Dec s -48 17 14   Mag 12.3   Size 2.6′ x 1.2′

DSS image
NGC 6868 & NGC 6870. DSS image

How astonishing is it to sit in your backyard (well, in this case a rather monumental backyard) with your backyard telescopium and in one slew, time-travel back 120 million years and pick up the ancient photons streaming in from a giant galaxy?

NGC 6868 galaxy lies at the heart of the Abell S85 galaxy cluster. Hartung mentions that it can be picked up with a 4” scope (from dark skies) At high power it shows as a bright small silky oval glow that grows brighter towards its bright round core which is concentrated to the centre.

NGC 6870, lying to the NE of NGC 6868 forms a close pair with it. Also a nice contrast of shapes as it is very elongated – a wisp of soft diffuse light with a bright little core.

There is a third companion, ESO 233-35, that lies 8’ west of NGC 6870 but I couldn’t catch it. I thought I maybe caught a tantalising flicker of a tiny stellar glow with averted vision, but it didn’t reappear so it appears it was but wishful thinking.

NGC 6861 – Galaxy 

RA 20 07 19.4   Dec -48 22 14   Mag 11.1   Size 2.8′ x 1.8′

DSS image
NGC 6861. DSS image

This galaxy, also a member of the Abell S85 galaxy cluster (and the second brightest), shows at higher power, a small, but pretty bright oval glow that brightens towards its small but prominent core. Two nearby mag 12 stars, to the east and NE run parallel to the major axis of the galaxy and form a pretty little triangle.

IC 4699 – Planetary Nebula

RA 18 18 32.1   Dec -45 59 02   Mag 13.0   Size 14″

DSS image
IC 4699. DSS image

At high power and without a filter, couldn’t see it, but as soon as I popped on the O111 filter it popped into view – a tiny greyish disc, like a small dim fuzzy star among a lot of small dim not-fuzzy stars.

NGC 6851 – Galaxy 

RA 20 03 34.5   Dec -48 17 05   Mag 11.8   Size 2.0′ x 1.5′

DSS image
NGC 6851. DSS image

At high magnification, it shows a slightly bright, small oval glow that brightens to a fairly bright little core. Two roughly mag 10 stars lie 5’ and 13’ SE.

ESO 231-30 – Open Cluster

RA 19 16 54.0   Dec -51 29 00   Mag –   Size 20′

DSS image
DSS image

A faint, delicate, small little open cluster, and although it’s pretty faint it stands out quite well against the star field. It is a thin triangle shape, pointing south. Its brightest member is a lovely 7.9 mag reddish star on the eastern side.

Some nice stars…


h 5033 – Quadruple star

RA 18 15.4   Dec -48 51   

AB:  PA 114°  Sep 17.2″  Mag1 6.8.  Mag2 9.8;   

AD: PA 69°  Sep 25.5″  Mag1 6.8.  Mag2 10.7
A pretty grouping of different coloured stars which is always a visual treat! The primary star is a gorgeous orange. B is a darkish yellowish star; C is a fainter greyish-white star and D a nice white star. The field is also very attractive  – full of sparklers – which always enhances the view when you’re observing doubles and multiples.


h 5034 – Double star

RA 18 16.2   Dec -46 01   PA 98°  Sep 2.2″  Mag1 7.5.  Mag2 8.6   

A lovely little close pair set against a pretty starry field. Both are white, moderately bright, but uneven.


h 5041 – Double star

RA 18 25.8   Dec -53 38   PA 260°  Sep 3.0″  Mag1 7.3.  Mag2 9.2

A beautiful little pair. The primary star is a brightish yellow; its companion a moderately bright creamy white. There is a lovely little patch of stars about 8′ SE with a delightful little faint pair (always a treat to have a surprise double, especially when you “discover” it… or more like it, stumble across it).


h 5045 – Double star

RA 18 30.9   Dec -48 01   PA 21°  Sep 8.1″  Mag1 6.7.  Mag2 9.7

The primary star is a bright yellow; its companion a faintish very pale white-yellow. A nice moderately starry field.


Dun 225 – Double star

Ra 19 12.4   Dec -51 48   PA 250°  Sep 70.1″  Mag1 7.2.  Mag2 8.4

This is a very wide pair. The primary star is a lovely orange; the B star is a pale lemonmy yellow. A much fainter greyish-white star lies between the two members. The field is moderately starry.


h 5114 – Quadruple star

RA 19 27.8   Dec -54 20   

AB:  PA 238°  Sep 75.1″  Mag1 5.9.  Mag2 8.2;   

AD: PA 94°  Sep 72.9″  Mag1 5.9.  Mag2 10.9 
Another pretty grouping – a very broad arc of prettily coloured stars. The primary star is a lovely orange; the B star shows a soft yellowy tint and has a faint whitish-grey companion at 8” SW. D is a creamy-white star. Pretty field.


Dun 227 – Double star   

RA 19 52.6   Dec -54 58   PA 148°  Sep 23.0″  Mag1 5.8.  Mag2 6.4

A beautiful pair. Lovely contrast. The primary star is a bright yellow; its companion cream-white. A moderately starry field.


Copyright © Susan Young 2016