Mars
Opposition 2020
In Harry
Potter, a Centaur surveys the sky through the trees of the Forbidden Forest at
Hogwarts and opines, ‘Mars is bright tonight’, a portent of Voldemort’s return.
In reality, Mars is regularly bright for no more sinister reason than orbital
mechanics: every couple of years when it’s near ‘opposition’, when its orbit
brings it to the opposite side of Earth from the Sun and so close by.
Right now
(yesterday, the 14th October 2020 to be precise) Mars is again
in opposition, although exact orbital alignments mean Mars was actually at its
closest to Earth a few days earlier. It’s impossible to miss - that brilliant
yellowish (not red in R.L.) star rising in the west from mid evening. Unlike
other recent oppositions though, Mars gets good and high in the sky for
northern latitudes this time, crossing the meridian here at about one in the
morning local time at an altitude over forty degrees. And even though this
isn’t the closest opposition in this cycle (that was the ‘perihelic’
opposition of 2016) it’s only about 10% smaller and much better placed here in
Europe – perfect for viewing or imaging!
Mars’
closest 2020 approach around the 6th October was a total
weather washout for me and I thought opposition night was going the same way. I
got a quick look at about nine thirty with a 4” Takahashi FC-100DZ refractor
from my balcony, just enough to spot some tantalising albedo markings at 200x.
But no sooner had I got my dome open than the clouds rolled in, typical!
Then, just
as I was already in bed and dozing at midnight, I spotted a brilliant yellow
star through a gap in the curtains. I waited to see if it would blink out
behind clouds again, but it didn’t. So I reluctantly
dragged myself back out of bed, knowing I’d regret it if I was lazy. A clear
dark sky, cool but not cold and with just a few scudding clouds, greeted me as
I stepped into the garden. The stars were steady, not twinkling, the
all-important sign of good seeing. Mars was so bright those stars around looked
dim.
I soon had
the dome back open and my 7” refractor pointing at Mars over the roof of my
house. A pair of 5mm Nagler eyepieces and an old
binoviewer giving 280x gave a fabulous view. The atmosphere held still, as
those twinkle-free stars had promised. Mars has a similar rotational period to
Earth, so the visible part varies slowly from night to night and tonight was a
view with special significance for me, beyond the closeness of opposition.
What I
could see on the (large for Mars) 22.3” full disc, was this: a broad swathe of
dark markings and a tiny bright polar cap in the southern hemisphere. In the
northern half, an expanse of seemingly featureless ochre desert shimmered
tantalisingly. I have a lifelong fascination with volcanoes and it so happens
that the largest one known anywhere was lost somewhere in that desert.
Generally, Olympus Mons, the largest of a group of giant volcanoes in the Tharsis region, is only visible when it’s covered in white
cloud (‘Nix Olympica’, the ‘snows’ of Olympus). Not
much cloud tonight, but that didn’t stop me looking. And looking …
For the
next hour or two, I relaxed in the red-lit quiet of my observatory and enjoyed
Mars as I only rarely get to see it – a proper little world with real details
visible whenever the seeing went especially still. This is the simple,
immediate visual astronomy I like best. Eventually I resolved darker lobes and
subtle E-W bands in the shaded southern region and a dark streak in the far
south east. Meanwhile, some blueish bright areas on the far western limb were
probably patches of hazy high cloud. In occasional split-second moments the
view stilled further to reveal fleeting structure within the dark areas, a hint
maybe of why Lowell and other believed they saw canals. No artist, but I tried
to sketch what I’d seen.
Then, in
the small hours with Mars descending past the meridian, the seeing steadied
even more. My local female Tawny owl screeched from the copse
across the field and some cat (I hoped!) howled from the gardens up the road. I
waited. Eventually, a spot or two flickered out from that ochre desert in the
Martian north west and were gone in an instant. I recorded, ‘Spots! Volcanoes?’
on my sketch. Imagination? Or had I really glimpsed Olympus Mons? Well,
perhaps. Then again, Mars will be well placed on the run-up to Christmas of
this strange year of 2020; and if I’m lucky I’ll get to search for Mars’
volcanoes again.
Mars
rising above my chimney pot!