Article written: 3 Dec , 2008
Updated: 24 Dec , 2015


The small constellation of Microscopium resides just south of the ecliptic plane and was created by Nicolas Louis de Lacaille. It was adopted by the International Astronomical Union and accepted as one of the permanent 88 modern constellations. Microscopium covers approximately 210 square degrees of sky and contains 5 very dim stars in its asterism. It has 13 Bayer/Flamsteed designated stars within its confines and is bordered by the constellations of Capricornus, Sagittarius, Telescopium, Indus, Grus and Piscis Austrinus. It can be seen by observers located at latitudes between +45° and ?90° and is best seen at culmination during the month of September.

Because Microscopium is considered a “new” constellation, it has no mythology associated with it – but Nicolas Louis de Lacaille was a man of science and the constellation names he chose to add to his southern star catalog – Coelum Australe Stelliferum – favored this love of technological advances. During Lacaille’s time, the microscope wasn’t a particular new invention, having been created by Hans Lippershey (who also developed the first real telescope) over 100 years earlier, but it was making some serious optical advances when Anton van Leeuwenhoek’s work popularized it in Lacaille’s world. Although the dim stars bear no real resemblance to an actual microscope – who can fault him for his love of science and optics? After all… He was exploring the southern hemisphere with a half inch diameter spyglass and discovering all kinds of deep sky wonders!

Let’s begin our binocular tour of Microscopium with barely visible Alpha Microscopii – the “a” symbol on our map. At a distance of 380 light years from Earth, this G-class giant star shines with the candlepower of 163 Suns. It’s a helium fusing customer – busy working on developing its carbon-oxygen core and just minding its own business. Alpha ignited some 420 million years ago as a class B8 hydrogen-fusing dwarf and has been quiet ever since… But take a closer look in a telescope. Do you see a 10th magnitude companion star? Say hello to Alpha B. While many folks might argue that Alpha B isn’t a true binary star companion, research has shown that it has it has moved seven arc seconds closer to the primary since 1834. A pretty good indication or orbital motion, don’t you think?

Now turn your binoculars toward Theta 1 Microscopii – the curved “U1″ on our map. Here we have a variable star – but not by much. Theta1 Microscopii is an Alpha CV type star with a very small magnitude range of 4.77 to 4.87 every 2 days, 2 hours and 55 minutes. Not revealed on our map (because the symbols would be too close) is Theta 2 just to the southeast (21h 24.4m, -41 00′). Theta 2 is a very nice binary star, but it will require the use of a telescope at high magnification to split this 6.4 and 7th magnitude pair. Theta 1 and 2 will be a great optical double star for binoculars!

Get out the big telescope and let’s take a look at NGC 6925 (RA 20h 34.3m, Dec. -31 59′). At slightly fainter than magnitude 11, this inclined spiral galaxy is going to require dark skies to get a view, but it’s worth it. NGC 6925 is home to a mega-maser – water vapor being collected in the black hole of an active galactic nuclei! Look for a very stellar nucleus and just a wisp of extension.

More? Then try your luck with NGC 7057 (RA 21h 24m 58.5s Dec -42° 27′ 38.0”). This little elliptical galaxy runs around magnitude 12 and it isn’t going to be easy, either. What challenge is? Since it is a very isolated elliptical, it was used in studies to compare star formation rates between interacting and merging galaxies as opposed to those with no close companions. Believe it or not, according to Bergvall (et al) “from the global star formation aspect, generally (they) do not differ dramatically from scaled up versions of normal, isolated galaxies.”

How about IC 5105 (21h 24m 22.0s Dec -40° 32′ 14.0″)? Let us know if you see anything there! Supposedly there is an elliptical galaxy in this position and it has been studied for its stellar population and infrared emissions. Maybe we need infrared just to see it! Kinda’ like Microscopium, huh?


Chart courtesy of Your Sky.

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