This was the first sketch I completed at Astrofest. I've been wanting to sketch this beautiful
dark nebula ever since I first laid eye on it some three years ago. This dark nebula, B86, goes by the popular
name of "The Ink Spot". It sits
smack bang in the centre of the densest star cloud in the whole sky, the Cloud
of Sagittarius. And what sets it off
even more is B86 has a gorgeous bright open cluster right next to it, NGC
6570. Both objects are more-or-less the
same size as each other, even though both are not very large themselves. But it is the juxtaposition of these two very
different objects against the blaze of the Milky Way that makes this pair a
spectacular pairing.
Dark nebulae are clouds of dust and gas that are drifting
through the Milky Way galaxy. Many of
these conglomerations of dust and gas do end up being formed into stars and
planets, but most just end up forming the fabric of the galaxy. In fact, the stars that we see actually only
form a small percentage of the actual mass of galaxies. By far the greatest amount of a galaxy's mass
comes from this very dust and gas. The
Ink Spot is a small patch of cloud. It
is a very opaque nebula too. Dark
nebulae are categorised according to their opacity, or how dark they are. The scale of opacity goes from 1 (very
tenuous) through to 6 (very opaque).
While the opacity of The Ink Spot may be a 5, it is because that it sits
in the Cloud of Sagittarius that makes is a striking object.
The little open cluster NGC 6520 really works very well in
setting off B86. Open clusters are
groupings of stars that are all related to each other having been formed out of
the same parent cloud of gas and dust.
Evidence for this is seen in the spectra of the stars displaying the
same chemical make up. The brothers and
sisters of our own Sun have been identified this way, with the same chemical
signature as our Sun having been identified in several close by stars even
though the Sun's 'siblings' have long drifted off away from each other. Open clusters are loose groupings too, so
even though they formed from the same source, their gravitational connection to
each other is not strong enough to keep the group together for too long.
For me, this tiny patch of sky is one of my most favourite. Tiny and oh so precious. Brilliant, dark, stark, ghostly. All in one. Gorgeous.
Object: The Ink Spot,
B86 & NGC 6570
Telescope: 17.5"
push-pull Karee dob
Gear: 13mm LVW, 154X
Location: Linville,
Queensland, Australia
Date: 24th July, 2014
Media: Soft pastel,
charcoal and white ink on A4 size black paper.
Duration: approx.
3hrs
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