The lost deep sky discoveries with the Great Melbourne Telescope

[Steve Gottlieb]

The Great Melbourne Telescope, generally considered a Great failure, was only credited with two minor discoveries in the NGC despite 20 years of active service. With a 48-inch aperture (speculum mirror), I always found it hard to believe that additional southern galaxies as well as new LMC clusters and nebulae weren't discovered with this enormous scope.

I recently searched the National Archives of Australia website and found they had digital copies of observing logs for the GMT. I was excited to find that nearly 70 discoveries made with the GMT were never published, mostly by Pietro Baracchi between 1884 and 1888. As an example, Baracchi made 17 uncredited discoveries in the Centaurus cluster, 6 in the Hydra I cluster and 6 in the Antlia cluster.


You can read "The lost Deep Sky discoveries with the Great Melbourne Telescope" on my Adventures in Deep Space. I've included data on all the discoveries, as well as my observing notes on many of these.

Susan Young also created an excellent blog titled "The Baracchi 59" on her website Sand & Stars. She includes a short biography of Baracchi and more information on the GMT.

These lost discoveries should make a Great observing challenge for southern observers!

[SusanY]

Hi Steve,
Great to see that you posted the lost discoveries of the GMT; what a fabulous telescope! And it does indeed make a fantastic observing challenge for southern observers - there really are some wonderful little treasures to be seen!

As you know, this last dark cycle I began my “Baracchi 59” quest - unfortunately stymied most nights by the most ferocious and unseasonal winds so I only managed to observe his LMC and SMC objects. Thus...

Using my 16" Dobs, I began in the LMC with the first of Baracchi's discoveries - (1) S-L 92 - and Baracchi certainly described it well when, as you note, he questioned why Joseph Turner, the previous observer on the 48-inch, had missed this nebula and wrote, "It is very faint but not fainter than [NGC 1749]. You can't say what shape it has - but it is there." Quite apart from also wondering how Turner missed it, I examined the small, faint glow extremely carefully and indeed one can’t say what shape it is (it epitomises the word amorphous), but it is there! What a start to the Baracchi 59!!

In fact, observing the Baracchi LMC objects is undiluted bliss... I had decided before beginning that I wouldn’t hop straight to the Baracchi objects but begin by carefully examining the object(s) that Baracchi was examining when he made each discovery. You can imagine what a rich experience this provides in the LMC: for example, on 18 Dec 1884 he discovered NGC 2043, NGC 2072 and NGC 2059A while observing a field of clusters that includes NGC 2046, 2047, 2057, 2058, 2059, 2065 and 2066 - a spectacular bunch of objects right there, and even though I have seen them all before it was really something to see them anew and in conjunction with the three discoveries. I also, because the Cloud is simply chock-a-block full of stuff, take a squizz at any other faint S-L and (unfiltered) Henize objects in the close vicinity which all warrant a little comparison and ponder at how Baracchi missed them while picking up his faint discoveries. It is all making for a wonderful and very unhurried observing programme... and very long log entries!!

Thus it was I observed the rest of his LMC objects: (2) S-L 676; (3) S-L 684; (4) NGC 2043; (5) NGC 2072; (6) NGC 2059A; (7) S-L 692 and (42) S-L 556. But before leaving the LMC I couldn’t resist yet another look at glorious little Hodge 301 that as you note: “Baracchi clearly included the compact open cluster Hodge 301, situated 3' northwest of the center of the Tarantula Nebula, in a sketch made on 24 Jun 1884. He didn't describe this cluster, only noting how prominent the central cluster (R136) appeared.” I am surprised he didn’t describe this cluster, albeit small it is a very prominent little cluster, not to mention very beautiful (but then again, I am biased, this is one of my favourite clusters in the LMC!)

Then it was off to the SMC: (56) Bruck 67; (57) Kron 25; and (58) Henize SMC-N45. I will add here that one certainly needs a very dark sky, good dark adaptation, lots of averted vision and plenty of time to allow the brain and eye to adjust to the scene in order to truly appreciate Baracchi’s discoveries, although having his handy sign posts makes it very easy to find the objects in the two Clouds!

And then alas, the dust devils came howling in and that was it.

Susan

[Raul Leon]

Very informative, I only wish I could observe the SMC & LMC, thanks for posting, Raul