Friday, 29 July 2016

My Sketch Pad Rig

Hi all,

Thought I'd share the sketch pad rig that I use, and how I came about to creating it.  Pretty much a case of necessity being the mother of invention, but into the mix was some good fortune and the local council elections!

You will find the article in the "Telescope Bits and Bods" page of my blog.  There you will find other bits and pieces that I've come up with too.


Tuesday, 26 July 2016

Back to School - a lesson from new friends.

Hi all,

The last DSO sketch I did, that of the Lagoon Nebula, you may recall I was not totally happy with.  Thing is, I encountered a limitation of the soft pastel dust I use with the Mellish Technique.  The limitation is not being able to lay down a sufficiently dense/brilliant amount of the soft pastel dust.  This is not normally a problem.  However, occasionally there is an object that has a particularly brilliant glow, such as the central hub of the Lagoon Nebula, and also the glowing nebulosity immediately around the Trapezium in the Orion Nebula.  Come to think of it, my last sketch of M42 planted the seed of dissatisfaction as I really was not too happy with the shading density/opacity of the area around the Trapezium.  And this Lagoon Nebula sketch brought it to a head.

A friend of mine, astronomer Dr Renee James, introduced me to a close friend of her's, artist Lee Jamieson.  The correspondence we've shared regarding my work led to Lee suggesting I try powder pigment colours, such as powdered titanium dioxide or zinc oxide.  These pure pigment colours are essentially pure titanium and zinc compounds.  Lee mentioned that these powders would be of a fine grain size than the soft pastel dust, and much more dense in opacity, and not filled with binder material, such as calcium carbonate that is typically used in soft pastels.

This suggestion really caught my attention and imagination.  My initial thinking being that these powders would be like using a sledge hammer to swat a fly if I wasn't careful.  But, these could also be the answer to the brilliance problem I had encountered.

I just had to get my hands on some of this stuff!!!

And thankfully, my local art store is very well stocked, and carries both of these powder pigments.  I picked up a little tub of the titanium dioxide as the zinc dioxide is a little more translucent.

So to test the new powder, I brought up a black and white image of the Lagoon nebula that closely resembled its appearance through a telescope.  I started the sketch as ususal with the pulverised soft pastel.  Once completed, I took to the central areas with the powdered pigment - the results were immediate!

Those areas that I struggled to achieve the desired brilliance now absolutely glow!

Compare with the sketch I did just a few weeks ago.  I was just not able to generate the same brilliance in the right hand lobe and the stripe of material beside the star cluster.

If you decide to use these powdered pigments, be aware that these colours are very brilliant due to their greater opacity compared to powdered soft pastels.  Start very sparingly with it as it is very easy to overdo the intensity of the white.

I can't wait to use this new tool out under the stars next time!


Wednesday, 20 July 2016

Schickard & Bailly - ancient features prove most intriguing

Hello everyone,

Finally another break in this run of poor weather for a visit to the Moon.

And two consecutive nights too!

As things have transpired, the last few visits to the Moon for me have been close to the Full Moon phase.  Not a complaint, just an observation on the coincidence.  For me, ANY time I get with the Moon of late is welcome.

Both sketches I managed were of very ancient features on the Moon.  So both show their age with their own set of tell-tale features.  And each also offered different sets of features that made each appealing to work on.

The first piece was centred on the ancient crater Schickard.  Schickard is just about a ghost crater now.  Having being formed long ago when the Moon’s crust was thin, the impact saw most of the crater filled in with lava, leaving just the rim.  But today this rim has been just about totally obliterated from the thunderous shaking and jolts it has experienced over billions of years of subsequent impacts, shaking the rim to almost flat today, with just the flooded crater mostly intact.  Not really surprising though as the rim is essentially just pulverised material with no structural integrity, just like dry sand, and the flooded floor being pretty much just a solid lump of rock.

What is intriguing about Schickard is the patch-work nature of its flooded interior.  From its age, one would expect a uniform colouration of the fill material.  Weathering of the lunar surface happens as a result of solar wind reacting with the material on the lunar surface.  The darker the material, the older it is, as newer impacts throw up fresh, unweathered material.  This is why craters such as Tyco and Copernicus are so bright.  Over time, these too will lose their brilliance.

Yet the fill material of Schickard is varied in colouration.  And there is a clue to the reason for this variation in colour through the internal feature of Schickard 1, a volcano.

Volcanos inside craters is a common feature of ancient, flooded craters.  It tells of continued volcanic activity on the Moon long after the original impact opened the thin crust, and lava filled the hollow.  Schickard’s stained floor, and the volcanic dome, can only mean that there was a significant change in the composition of the lava over subsequent eruptions.  The change in composition then explains the difference in colouration as the solar wind reacts differently with different lava compounds.  Curiously too, Schickard 1, the volcano, is the single brightest feature inside Schickard.  Schickard1 is the bright spot just to the right of centre.

To the South of Schickard is a trio of craters that form a very interesting grouping.  What caught my eye about this grouping is the flooded floors of all three give the impression of being higher than the surrounding moonscape.  According to Virtual Moon Atlas, they are!

Object:  Crater Schickard and surrounds
Scope:  C8, 8” SCT
Gear:  8mm LVW, 250X
Date:  18th July, 2016
Location:  Sydney, Australia
Media:  Soft pastels, charcoal & white ink on A4 black paper.

Twenty two hours later I followed up the Schickard sketch with work of the largest crater on the Moon, Bailly.

What most attracted me to Bailly was the delicate shading and fine lines that riddled the entire circumference of the rim, internal and external.

Bailly sits on the western limb of the Moon.  The result being that it is very foreshortened, and the Moon’s libration altering the amount of foreshortening that is seen.  Its position on the limb is such that the Moon’s libration has Bailly come very close to but not quite disappearing behind the limb.

Bailly’s foreshortening provides for an exquisite range of delicate shading and details along the length of its rime.  And the damaged rim on ends of the major axis provide wonderful textures and curving lines as the adjacent moonscape and craters encroach on the rim of Bailly.

The moonscape in front of Bailly is oddly smooth, with a cluster of mid-sized craters providing textural variation.  Despite the similar size of these craters, the age of these craters varies greatly.  Some of these are flooded, while others have clear floors with central peaks.

Object:  Crater Bailly and surrounds
Scope:  C8, 8” SCT
Gear:  8mm LVW, 250X
Date:  18th July, 2016
Location:  Sydney, Australia
Media:  Soft pastels & charcoal on A4 black paper

These two pieces took over two hours each to complete.  A most satisfying few hours spent with the Moon.  I hope you enjoy these pieces too.


Tuesday, 5 July 2016

Beaten up shore side, and remembering a friend

Hi all,

This has not be the kindest year for myself so far this year with astronomy.  This weekend was my first good New Moon weekend since January.  Also the last couple of months from home, the atmosphere has been particularly turbulent with even the most modest of magnification showing a shimmering image, making sketching the Moon and Sun ney impossible.

On a more grave part, my good friend, Rod Hay, was tragically killed in an airplane accident in February.  Rod was the manager of Katoomba Airfield, the location of my dark sky site.  With Rod’s death, access to the Airfield to EVERYONE has had to be stopped until the murky business of insurance and new lease arrangements are determined.  Rod was a very experienced pilot & flying instructor, and welcoming of anyone who cared to show interest in flying and his dear Airfield.  One of Rod’s biggest boasts was that he had more students become commercial pilots than any other flying instructor!  Over the five years I had known Rod, my relationship with him and his partner grew beyond astronomy.  My little son and I came to have a little end of year ritual with just the two of us spending an evening up at the Airfield doing “boy stuff”.  My first hearing of Rod’s passing was from the TV news on the Sunday morning following the disappearance of his aircraft.  While no name was given of the missing pilot, other than that the pilot was a Katoomba local, sent a deathly shiver up my spine.  Tragically, it was Rod who was lost.

So, until the situation with the Airfield is settled, we as a group of astronomy friends have had to find a new home to exploit the night sky.  The trick has been to find a site that offers the unique set of parameters that made Katoomba Airfield such a fabulous location for astronomy:

·     *     Set high on a ridge, not in a valley – fog settles in a valley, leaving the ridge tops clear
·     *     Rocky or sandy ground, not turf – grass expels a lot of water during the night which becomes dew.  This can be just about eliminated by setting up on rocky terrain.  While there are measures by which to reduce the ill affects of dew on optics, if dew is not present from the start, then dew control measures may never need to be taken.
·      *    Away from the bane of light pollution.  Being set up high on a mountain greatly helps to as the reduced density of the atmosphere harbours less light pollution
·      *    Away from agricultural land as this has the same consequences as a grassy ground with dew

Katoomba Airfield offered all of these, plus it was a safe place for us to set up.  AND we were able to use the office which has a combustion heater which became the centre of the Universe on those freezing winter’s nights.

So, after a few months of pouring over maps, aerial photographs, asking people, councils, police and state authorities questions on possible locations, it looks like we have found a new home for our band of merry astronomers – roadside, deep within the western end of the Blue Mountains National Park, at Mount Victoria, on one of its higher peaks.  This almost barren ridgetop has a completely unobstructed 360° view of the horizon!  And as it turns out, this site has a gun-barrel view of the Sydney Harbour Bridge! some 92km away!  Holy cow!  Who would have thought that The Bridge would have been visible from so far away, and from the far side of the Great Dividing Range!

The Bridge and North Sydney buildings are visible from a tiny, tiny gap in the mountains.  The picture below shows the lumpy profile of Mt Banks in the east of the site.  The gap is a thin slither located off to the right of the shorter third peak of Mt Banks, and stopped by the yellow cliff face just beyond the right side of that same short third peak.

Wai Keen, one of the fellows who joined me at this new location, came up to take photos of the night sky.  Below is one of the lovely pieces he was happy for me to add to my blog.  It shows another mate who joined us, Mark, lying back enjoying the sky while he waited for his scope to take a photo.  I really like this composition,  What is also noteworthy of this photo is it shows what the sky looked like naked eye to us!  Brilliant!  Thanks for the photo Wai Keen :)

These photos were taken the first night we used this new location.

As things would be, when I arrived the sky was crystal clear.  On sunset, clouds rolled in from the west.  The next two hours were spent looking for holes in the clouds, and the holes slowly became larger and longer lasting until the full splendour of a totally unhindered sky came into view!  Magnificent!

I had hope to complete a few sketches this night.  The two first hours being lost to cloud meant that my initial plan went out the window.  Fatigue then set in, making concentrating and settling on a sketch difficult.  After a short sleep to refresh, I was ready to tackle a sketch.

I have sketched M8, the Lagoon Nebula, a few times over the years.  Yet never from a dark site.  What I didn’t anticipate was the level of complexity that The Lagoon shows from a dark site in a 17.5” scope.   Instead of being a flat glow, it is fibrous.  Instead of being tight and compact, it is enormously expansive and diffuse.  And instead of being a grey glow, it is bright with an almost electric blue tinge to it.  I also managed to pick up hints of a couple of the bok globules that inhabit M8.

This voyage over the Lagoon was a sobering experience in complexity.  It challenged my technical capability and acuity of examination.  I am not completely satisfied with this effort.  Don’t get me wrong, I’m not disappointed.  But I hope to revisit the Lagoon next month and have another shot at it – weather permitting.

Object:  M8, The Lagoon Nebula
Scope:  17.5” push-pull Karee dob
Gear:  24mm 82° eyepiece, 83X
Date:  3rd July, 2016
Location:  Mt Victoria, NSW, Australia
Media:  Soft pastel, charcoal and white ink on A3 size black paper