EVENING TWILIGHT TOTAL LUNAR ECLIPSE
Lake George (35km NE of Canberra)
November 8th, 2022
Introduction
In June 1993, two years after Mt Pinatubo erupted in 1991, I observed
the darkest lunar eclipse I have ever witnessed with my friend Greg
Bond from my backyard in Canberra. The Moon, at mid-eclipse, was just a
ghostly dull charcoal brown colour, barely any colour to the naked eye,
and definitely not obvious in the sky.
My hopes for a repeat event in the wake of the
Hunga-Tonga-Hunga-Ha'apai volcano eruption last January 15 weren't to
be realized. I'm afraid that 1993 amazingly dark eclipse is probably
going to be a once in a lifetime experience.
For a week before the event, weather models were predicting cloud to
block Tuesday night's view of the lunar eclipse across most of the ACT.
However, the models predictions were consistent, day after day which is
an indication of good reliability of prediction. Dispite the dismal
forecast for Canberra, just 35km northeast of the CBD at Lake
George, multiple models were predicting also with great consistency,
clear skies all evening. Those predictions transpired to be correct. In
the course of the whole evening, small clouds drifted across the Moon
on just two occasions for a minute or two each time. The rest of the
night we had a perfectly clear view of the whole event. It was a mostly
mild evening, it didn't cool down until after 10:00pm.
Eclipse Day
I made arrangements to view the eclipse with a friend of mine.
Given that Lake George is such a short drive, we travelled in separate
cars so that we could each go home whenever we felt like it.
I drove out to the lake straight after work to set up my EM200
equatorial mount before sunset with a DSLR at the prime focus of my
ED80 mounted side by side with an Orion 102 Maksutov with a 21mm
Denkmeier, [60x, ~ 1 degree field] for visual observing.
I polar aligned the mount in daylight using my Google Earth method.
Using a square, I sighting the edge of the square on wind generator
tower that was due east of my lakeshore location. I then used an
inclinometer to set the altitude of the polar axis. This gave me
excellent alignment, more than adequate for an eclipse. The Moon's
image only drifted very slightly over the next 6 hrs of tracking.
About 30 mins before the Moon rose, my friend arrived at the lakeshore
site and set up her tripod and camera with an 11-16mm lens.
The Moon rose over the hills across the lake about 40mins
before the commencement of the partial eclipse. The partial eclipse
progressed for just over an hour. I tried to pace myself. Although I
had spare memory cards and batteries, it is very easy to end up with
stupidly high numbers of frames that you never ever use.
I had made a detailed plan for a multiple exposure to be taken with my
second camera. Unfortunately, I forgot the bag with my second
camera and all my intervalometers at home. I gave my friend the plan
and showed her the required sequencing and exposure changes. Felicity
didn't have an intervalometer and as mentioned, all mine were in the
second camera bag with the spare camera body.
Photo credit: Captures: Felicity Latchford Processing: Joe Cali
The sequence intervals aren't quite perfect but she did a pretty
amazing job. This event was 4 hrs long, as long as a double marathon of
manually triggering the shutter at 5 min intervals with a single cable
switch using only an iPhone for timing. She doesn't have Photoshop so
the next day I processed and stacked her images into this composite.
For my money I think it looks great!
Later in the
partial eclipse I could see a nice blue transition band at the shadow
edge in my photos but could not discern any blue visually in the
Maksutov telescope. With the onset of totality, the Moon exhibited its
typical dull coppery red colour.
All of the images have been cropped. Below is a full frame image showing Uranus which was located just 1o from the eclipsed Moon.
I recorded some
more blue banding during egress of the shadow. These colours come from
the Earth's atmosphere and are caused by the same scattering and
absorption of light that causes the same red to blue transition we see
at sunrise and sunset. To the best of my memory, I have never seen the
blue banding to the naked eye, but it's easily recorded
photographically. Through the telescope, the image was so dark that we
saw less colour than with the naked eye and from memory, I haven't used
anything bigger than a small refractor to observe a lunar eclipse for a
very long time. Some day, I must try observing a lunar eclipse with one
of my larger aperture instruments. Perhaps I'll glimpse the blue.
The partial phase finished at 11:49 pm local time. We didn't stay for
the penumbral and didn't waste any time packing up as we both had to be
at work next morning. We left the site just after midnight local time
and with a short drive home down the highway arrived home at 12:45am.
