Thursday, 31 December 2015

Low magnification Copernicus

There is a trap we can fall into with the Moon – we want to push magnification as far as possible all the time.  And if conditions are not up to scratch, we abandon efforts.

A recent sketch I saw on an astro forum reminded me that any telescope is better than no telescope.  So if your scope is of a small aperture, it is still an exquisite asset.

So, what do the two above statements have to do with anything?  Well, it means that you make use of what scope and conditions present.

This forth straight night of clear skies, conditions were particularly poor.  Even at 100X, the image of the Moon was showing a shimmering boil.  At another time I would just have packed up the old orange tube C8.  But the memory of that earlier sketch done using a smaller aperture had me take courage at looking at using much lower magnification than I would typically use.

This night, magnification at under 100X showed a minimal amount of boil, and this was to be the magnification to sketch the Moon with.

Even 91X, the amount of detail is staggering to behold.  The image though smaller, is much more concentrated.  This night I chose to revisit an old friend, Copernicus, and the surrounding maria and mountain ranges.  For me, mountain ranges prove the most difficult to replicate.  The detail is frightfully complex, and my eye struggles to accept just one point of detail, instead trying to absorb a dozen!  Tonight was a chance to take up a mountain range challenge too.

Copernicus was staggering.  The mountain range Montes Carpatus to the north appearing from over the terminus into the morning light with spectacular shadows.  To the south is Reinhold, with its crater floor still in complete shade.  To the east is Erastothenes, another big crater that is surrounded by a ring of secondary impacts created by ejecta material, just like Copernicus has.  Erastothenes is located off the end of the western spur of Montes Apenninus mountain range.

Further north of Copernicus, the terminator is rolling over the middle of Mare Imbrium.  The terminator here has a lovely, smooth rolling appearance.

And of course, there is the ray system radiating out from Copernicus, spread out over the surrounding maria.

I hope you enjoy this piece.


Object:  Copernicus and surrounds
Scope:  C8, 8” SCT
Gear:  22mm LVW, 91X
Date:  20th December, 2015
Location:  Sydney, Australia

Media:  Soft pastels, charcoal and white ink on black paper.

Saturday, 26 December 2015

Maginus, and this time no clouds...

I had a fabulous run of clear skies and the chance to sketch.  Three nights in a row.

Conditions this night were the best for a very long time.  400X was showing some ‘boil’, but still very acceptable.

In scanning the terminator for a sketch subject, I came across Magnius.  I had attempted to sketch Maginus one time before – on that occasion clouds rolled in, killing off the sketch session early.

Maginus is a very ancient feature.  Its floor is flooded, with the tips of the central peaks just showing.  The peaks, and the sheer size of Maginus are the only features still keeping the semblance of the original crater.  Otherwise, it has been heavily altered by the successive impacts that are slowly obliterating the remains of Maginus.

It is these newer impacts superimposed onto the massive ancient crater that make this a very attractive sketching subject.  The floor of Maginus is surprisingly clear of particularly major impacts, with the major newer impacts doing their best to obliterate the ramparts (wall structures) of the underlying crater.  This grace of luck has left the remains of the central peaks visible, and the remainder of the floor peppered with smaller impacts.

Maginus makes for a fantastic telescopic target.  Highly tortured, and littered with hundreds of craters inside and surrounding Maginus, and the floor making for a good test of conditions to be able to spy out the mass of tiny impacts.   Curious to call these craterlets at ‘tiny’, as the ‘tiny’ craters still range from 500m to 2km in diameter!  Bloody big holes all the same!


Object:  Crater Maginus and surrounds
Telescope:  C8, 8” SCT
Gear:  5mm Hyperion, 400X
Date:  19th December, 2015
Location:  Sydney, Australia
Media:  Soft pastels, charcoal and white ink on black paper.

Tuesday, 22 December 2015

Rima Hyginus - homage to my first telescope

 I got my first telescope when I was 13 years old.  A modest 50mm Tasco refractor.  At the time I thought it was the bee’s knees.

Though a modest little scope, I first saw Saturn with it, Halley’s Comet, and of cause, the Moon.

The little Tasco came with a map of the Moon, and I spent many hours studying it.  It also showed several rile systems, including Rima Hyginus, which I managed to see with it!  The thrill of seeing such a fine line traced on the lunar surface was one I have never forgotten.

Unlike the previous night, conditions were not as steady.  An 8mm eyepiece showed just too much ‘boil’ in the image.  My modest little 9mm TMB Type ii proved a better choice for the evening.  Might not seem like too much of a magnification difference, but it was sufficient to reduce the boil to a tolerable amount.

This night, while looking for a sketching target, I came across Rima Hyginus, and that happy memory of my first view of it came rushing back.  So, this night I sketched Rima Hyginus to commemorate my experiences with that little Tasco and what it showed me.

Rima Hyginus lies between Mare Vaporum & Sinus Medii, and carves a curious line that makes a turn about halfway through its ripping of the lunar surface, with a crater so very conveniently smack bang on the elbow of the bend, which also give the rile its name.

To the North (right of the rile) lies a dark and tortured series of lava mountains.  On other occasions when Rima Hyginus looked like a sketch candidate, this dark area looked too sinister and difficult to lay down.  No escaping this time.  I found it a lovely area to sketch!  Very detailed and intricate.

To the east of Hyginus, a second long rile system, Rima Ariadaeus.  Together the riles make for a spectacular area.

Object:  Rima Hyginus
Scope:  C8, 8” SCT
Gear:  9mm TMB Type ii, 222X
Date:  18th December, 2015
Location:  Sydney, Australia

Media:  soft pastels, charcoal and white ink on black paper.

Saturday, 19 December 2015

Posidonius et Lacus Somniorum - a volcanic paradise

Finally, a clear night, the Moon is up, and I have time for a sketch!  I’ve hit the jackpot!!

The feature I sketched tonight was one of the first features I sketched when I took up the pencil after many years, Posidonius.  I was not aware at the time that this was Posidonius – did not matter really as the features on offer were most exciting.

What was interesting for me once I found out the identity of the crater, was how much more I was able to identify and details I was able to pick out that previously made no sense to me.

Posidonius is not one of the oldest features.  In fact, it is really just middle aged.  For the oldest of features, a crater this size would have been totally flooded with lava, and only a ghost crater left – much smaller impacts than Posidonius can be seen close by which are totally flooded, making those features very, very ancient, much older than Posidonius (such as Le Monnier to the top left of Posidonius).  The youngest of features happened once the Moon’s crust was so thick that a crater this size on longer was able to punch through to the molten rock below.  Posidonius is one crater where the crust was punctured to allow for partial flooding, but the flooding was not complete, and now long extinct volcanos pot-mark its flooded floor and surrounds.

Posidonius is one extraordinary feature.  The partially flooded floor not only has many volcanic vent and domes, but it is also highly fractured, with several massive riles running through it.  Its walls are also very interesting.  Close examination shows what appears to be a second rim on the inside.  This is something I have not seen before.  There are a few co-centric craters on the Moon, but these all are on the small side.  Posidonius is some 100km in diameter – for a second concentric impact to happen of such a close size to the parent impact is just too much of a long shot.  The highly fractured crater floor may hold a clue to this apparent secondary crater – massive upheaval from subterranean magma forces pushing up.  Mind you, this is only speculation on my part.  There are other examples of magma lifted features on the Moon, which is why I suspect this may be the reason for the double rim.

Posidonius’ floor is not the only location of volcanism in this area.  Lacus Somniorum appears featureless, but is actually littered with domes all around Posidonius.  One clue to spotting the shield volcanoes is to look for totally isolated ‘mountains’ with no other mountain range within cooee of it, only an empty lava field.  This would make the chances of this solitary ‘mountain’ to actually be a shield volcano or Dome.


Object:  Posidonius et Lacus Somniorum
Scope:  C8, 8” SCT
Gear:  8mm LVW, 250X
Date:  17th Dec. 2015
Location:  Sydney, Australia

Media:  Soft pastels, charcoal and white in on black paper.

Sunday, 6 December 2015

More Sun and more learning...

Hello everyone,

The opportunity arose for a session with the Sun this Sunday morning.  Today a sector of the Sun contained several prominence features and some sunspot and filament activity.

The prominences on show were particularly fast moving.  Their shape and patterns changed markedly over the half hour of sketching them.  Such were the changes that I just could not go back to the first lot I laid down as the structures were pretty much totally altered.  This surprized me, and lesson learned about not leaving proms to come back to them – you just don’t know how fast these features are changing.

Conditions were not great today.  Thermal haze was constantly having the image come in and out of focus.  The chromosphere features are particularly sensitive to thermal haze, and it took some stubborn persistence to get the detail I wanted.  A nice cluster of sunspots and a lot of plages around them made for a great challenge to lay down.  Oh, if that haze would just stop!!!

When close to finishing this piece, it occurred to me to stop down the aperture of the scope, essentially out of curiosity just to see what would happen.  I got a lovely surprise that this helped to increase the contrast and made features easier to see with the magnification taken really low down.  Second lesson learned today.

My kids came out for a look when I completed my sketch.  I quietly mention to be patient with the red & black image as our eyes are not accustomed to seeing in such colours, and that the details will reveal themselves as if by magic.  And they always come up with great questions that test my knowledge and ability to answer their questions in terms that make sense to them, and not overwhelm them with science jargon.  I have an outreach night coming up in April with the Girl Guides’ – my kids’ questions make for some good practice!


Object:  Sun – (left to right) broken detached pyramid, mound & anomalous prominences, sunspots, plages & filaments
Scope:  ED80 f/7.5
Gear:  Daystar Quark, 25mm Pl, 101X
Date:  6th December, 2015, 10:30 am AEST
Location:  Sydney, Australia.

Media:  Coloured soft pastels & charcoal on A5 size black paper.