Hello everyone,
Well, it’s taken close to a year, but I’ve finally managed
to complete this HUGE sketch of the Large Magellanic Cloud for Prof. Renée
James! AND I found a system that helps
keep my paper DRY during dewy nights!
First the weather conspired to prevent any chance of an
early completion, by which time the LMC season had finished. I had to wait until November last year for
the new LMC season to begin, and the weather AGAIN delayed any chance of a
favourable sketching night until two weeks ago.
I had left the sketch last year with the majority of the nebulosity laid
down. I then had the opportunity in mid-January
for two crystal clear nights in which to complete the task.
If you recall, I had constructed a sketching rig especially
for this size sheet. The size of the
sheet I used with this sketch measures 510mm X 635mm. To the top of this rig I attached a pair of
100mm fans which I connected in series and runs on 12V. I attached the fans more only because I had
them and I thought I had nothing to lose if I try this idea. On the second night of the sketch, conditions
were very clear, but the easterly breeze that was blowing in from the coast
meant that dew was forming a couple of hours after sunset, and my paper was
beginning to dampen. So I turned on the
fans. To my great surprise, the fans
blew dry the damp and kept the paper bone dry the whole time I was sketching,
while everything around us was getting soaked with dew!
I am absolutely overjoyed at this dew control find! Sketching in dewy conditions has always been
a problem for me, and I just abandoned the exercise as it is impossible to work
with damp paper. This system that I
rigged up on a dumb whim of speculation proved to be the champion I needed to
keep my paper dry and me working! If it
were not for this sketch, I would never have found this solution. Thank you Renée!
As I had the fans connected in series, each fan was
effectively running on 6V, and their spin velocity was lower than if they were
running on 12V. Yet this air flow was
plenty to dry off the paper and keep it dry.
Connecting the fans in parallel would give me greater air flow, which
could be advantageous when dew is very heavy, but at the same time, if dew is
this heavy transparency would also be greatly diminished and less than ideal visibility. But it is something to consider and explore.
The sketch I have to say I am greatly relieved that it is
done. The sketch presented serval
technical challenges that I had to constantly keep on top of. The scope I used was a 100mm f/5 achromatic
refractor with a 30mm 82˚
eyepiece giving 17X magnification, and a true field of view of 5˚. The LMC measures some 12˚ X 12˚, no less than 6 times
the diameter of the full Moon, and nearly 3 times the true field of view given
by my scope/eyepiece combination. The
single biggest challenge was maintaining the scale of the piece and the
relative positions of the stars to each other.
Another challenge was keeping track of the different landmarks so I
could position the different features in their correct position, stars and
nebulosity the same.
There was another revelation that I found, though not as a
result of this sketch, but of something else I’ve been thinking about –
illumination of my work.
I REALLY dislike red light.
It is synonymous with astronomy the use of red light, but the reality is
that the use of red light in astronomy is entirely a throwback to the old dark
room days when red light was use to process black and white photographic
prints. The problem with red light is
our human eyes are not great in making out detail when the only source is a
feeble red light. To make out any
detail, such as reading a chart or finding something in your kit bag, the
brilliance needs to be increased and increased and this begins to stuff up your
night vision. I for one really struggle
to read my charts under red light, and my smartphone I run with the full colour
display, not the “red light display”, as it is impossible to effectively read a
dimly illuminated red coloured screen.
Red is a lousy colour for our human eyes to register contrast with.
Yet, if we slightly shorten the wavelength of the light we
are using, we can reduce the brilliance of the light, gain a marked improvement
in contrast when reading, and not compromise our dark adaptation – this was the
thinking I had, and there was only one way to prove this, by trying it out.
The size of this LMC sketch meant that I was positioned
further away from the paper than I would be otherwise. Making out the pinpoints of the stars I was
laying down with red light was impossible to see – all because our eyes are poor
in making out contrast under red light.
I had no choice but to try out the amber light.
What a difference it made, instantly! These amber LEDs are less brilliant than the
red ones of the lamp I use for my sketching.
Yet I was able to easily and clearly make out EVERY pinpoint I was
marking on the paper. As for my dark
adaptation and perception through the eyepiece?
No issues whatsoever! I
experienced no diminished dark adaptation at all. Instead, because the light I’m using is now
less brilliant, I have noticed my eyes are less stunned, and this only improves
my seeing.
I will be writing a separate blog entry about the use of
orange and amber lights. There I will
discuss in more detail the problems of red light, and the improvements that
there are to gain by changing our mindset of “red lights only in astro” to
instead a mindset that better takes into consideration our HUMAN eyes and the
ways that we can better work with them instead of against them.
Once the work out in the field was completed, at home in the
light of day I tidied up the sketch and touched up the piece to add those infinitely
tiny and impossible to individually lay down tiniest of stars that as a whole
lend their light to the overall visual appearance of the LMC. I used the same “machine gun” device I use
with globular clusters to give the necessary lift and life to the LMC. Without these the sketch remains flat and
lacking the necessary brilliance seen through the eyepiece. I’ve added a close up of the bar and
Tarantula nebula section to show this detail that the whole of sketch photo
just cannot reveal.
So, here it is. My
rendition of one of our closest intergalactic neighbours, the Large Magellanic
Cloud
Object: LMC
Scope: 100mm f/5
achromatic refractor
Gear: 30mm 82˚ eyepiece (17X, 5˚ TFOV), broad band
nebula filter and OIII + Hbeta hybrid filter
Location: Blackheath,
NSW, Australia
Date: over three
nights spread out over a year
Media: White soft
pastel, charcoal and white ink on black card (510mm X 635mm)
Duration: 9 hours at
the eyepiece, plus four more hours tidying and finishing off at home.
Close up photo of the bar and Tarantula Nebula area showing
the fainter machine-gunned stars that give the sketch the necessary lift and
life seen through the eyepiece.
A final revelation came to me about the LMC while I was
examining a photo of it by Marco Lorenzi.
A fantastic resource about the Magellanic Clouds is the brilliant
website Clouds of Magellan:
It contains very detailed charts of these galaxies, and
offers other resources such as links and even sketches of the Clouds and of
objects contained within.
The LMC is classed as a dwarf barred spiral galaxy. The bar is very conspicuous when viewing it
naked eye from a dark site. The arms are
however not noticeable, instead we see these as lobes on either side of the
bar. Even the majority of photographs
fail to capture the structure of the arms, instead the over processing of the
photograph washes out any trace. Yet I
noticed something very special about Marco’s photo when I was comparing it to
my sketch. The arms of the LMC are
actually visible in both Marco’s photo AND my sketch!
What is additionally revealed here is that the arms are not
perfectly symmetrical, as would be expected, because of the significant
influence of the gravitational tidal pull of the Milky Way on the LMC.
Yes, there is a magnificent barred spiral galaxy right over
our heads, with two sweeping arms that wrap themselves around the whole
structure. Yet, while most of us may
know of the spiral classification of the LMC, very few of us are actually aware
that of its true magnificent structure, mainly because of over processed
photographs, and of very few sketches of the whole galaxy. Marco’s photo is orientated in the same
direction of rotation as we see the LMC directly overhead. The LMC is rotating in a clockwise direction
when you view it naked eye. Due to the left-to-right flip of the image with a refractor, the LMC in my sketch it rotating anti-clockwise.
You will find Parts I and II of this project in the links below:
This sketch has been one big undertaking. From the start I was aware I had to do a lot
of prep work to get to terms with the size and complexity of the LMC. From a new sketching rig to accommodate the
larger sheet, to the provision of a dew control system (if initially only experimental,
but ultimately successful), and the need to adopt a different colour of
illumination. Then there were the
technical challenges out in the field beside the eyepiece and the challenges
crappy weather posed. Finally the
revelation of the true whole appearance of the LMC above our heads.
I sincerely hope that this sketch, and my experiences that
came with it, serve to INSPIRE you, not intimidate. I hope to inspire you to pick up a
pencil. Inspire you to not be shy about
tackling the seemingly impossible. And
to inspire you to challenge yourself and explore different ways of thinking not
only about sketching, but of how we go about doing our astro thing in the dark.
Clear skies and sharp pencils,
Alex Massey.
