Monday, 6 August 2018

Sunset at the Straight Wall reveals amazing detail

Hi all,

This is my second lunar sketch done using eyeglasses.  I’ve adapted a headband magnifier so it can carry a pair of spectacles suited to my eyes.  I’m getting used to the new way of sketching as there is now an additional step in my eyepiece-to-sketch-pad routine.  But the difference using these specs makes is well worth any initial discomfort.

I got up very early on Sunday morning for the chance to sketch something during the ¾ phase of the Moon.  As it turned out, seeing wasn’t the best despite the wee hour and cool temperature, but the occasional glimpses of remarkable clarity made the effort worthwhile all the same.

With all the lunar features on view tonight, it was an old favourite that most caught my attention, Rupes Recta, the Straight Wall.  I’ve sketch the Straight Wall during the ¼ phase as the Sun rose over this escarpment (see below), but this particular phase had the Sun setting, and the wall instead of being a dark shadow, was brilliant white, and the very low angle the sun was at cast the most remarkable long shadows and revealed a textured surface and details of this area of Mare Nubium that were jaw-dropping remarkable.

From the above sketch of the Straight Wall, the higher angle of the Sun leads one to think that the flooded ghost crater the Wall sits in is relatively smooth and not particularly textured.

Now, move the phase forward some 14 days, with the Sun casting its last rays across this same area at a glancing angle, and a staggering textured and tortured surface is revealed.  The Straight Wall and Rima Birt are not the only geological formations here.  Just west and running parallel to the Straight Wall is a long straight “depression” or fold that is roughly as long at the Straight Wall itself.  This long depression is crossed by Rima Birt, and continues on straight northward.

Rima Birt itself is remarkable in that its official selenologic origins are somewhat uncertain.  Most likely it is a rift fault that then allowed lava to erupt up along through the fault.  And as my sketch progressed, I picked up two volcanic domes (Birt 1 & 2) at the northern end of Rima Birt, the larger of the two sitting right on top of the rile!

The glancing angle of the fast setting sun also reveals so many other obscure features.  The oh-so-faint rims of several ghost craters are just barely visible – one being outlined by the chain of mountains, west of the Straight Wall, that circumvents and suggest the basin in which the Straight Wall sits in.  A highly pock-marked field of craterlets lies scattered south of Birt.  The faded ray system that extends southward belonging to Birt.  Several winding folds of old lava flows form wrinkles across the moonscape.  Long string-like streaks of light are cast eastward from the northern end of the Straight Wall across a jet black otherwise invisible plain.  And of course the curious twin peaks of dark shadows cast by the crater Birt across the brilliant white escarpment.

Object:  Sunset along the Straight Wall and surrounds.
Scope:  8” SCT
Gear:  10mm Pentax XW, 200X
Date:  5th August, 2018
Location:  Sydney, Australia
Media:   White and grey soft pastels, charcoal and white gel ink on A5 black paper

This was a remarkable session for me.   From starting not wanting to repeat a feature I had sketched before, a little time spent with it showed an astounding amount of invisible details revealed only by having the sun at as low an angle as possible before it dips below the horizon.   Quite superb!


Using Eyeglasses with Telescopes - one solution

Well, age has caught up with me.  I started to wear eyeglasses over the last couple of years as I’ve started to struggle with close up focusing.  This was fine with reading, but now I’m needing to use glasses with my sketching.  This has created a problem when I go to and fro between sketch pad and eyepiece and now needing to lift and replace the glasses from my nose.  This is a problem not just for those who sketch, but also for those people who make observing notes, and for microscope users too.

Lifting, holding and replacing traditional eyeglasses constantly is a fool’s game.  There had to be an easier way to make the switch.

I started looking into headband magnifiers.  Many of these come with an assortment of different lenses that provide different degrees of magnification.  I purchased a set that appeared to be light weight and as an added bonus has a pair of white LED lights built in.

My initial testing at home was most promising.  This headband set has a double articulating joint which allows or the lens to be lifted and for the whole LED assembly to be lifted too, and as the lens is attached to this element, the lens is able to clear the eyepiece safely.

The ultimate proof is using the headset at the scope while doing a sketch.  I used the headset on two occasions with the supplied lenses, once with a lunar sketch and the other with a DSO session.  As it turns out, the concept is good, but the supplied lenses are not.  The lenses are designed for close up work, and these lenses are not suitable for my purposes that has the sketch pad at a longer distance than these lenses work at.

Another problem with these lenses comes from the way they are made.  As the individual lenses are attached to each other with no spacing, the field of view when using these lenses is very narrow, and ultimately impractical.

My eyeglass script is mild, and at a pinch the ready-made glasses available at pharmacies  work well for me.  So, the thought occurred to me to swap the lenses that came with the headband for one of these inexpensive pharmacy eyeglasses.  If the experiment works, I can look at making a new set of lenses of my script.  By making use of these eyeglasses, I would also make the field of view much, much larger

So, I chopped up one of the supplied acrylic lenses to use the coupling mechanism it has, and attached it to the eyeglasses also using acrylic.  The arms on the eye glasses I cut off.  If I unscrewed the arms to remove the, it would have left two long tags would become a hindrance and get in the way when moving to and from the eyepiece.

Now for the third field test and proof of concept.  This was a lunar sketch.

The result was successful.  The new lenses are much easier to use, with no noticeable eye strain, and with a much larger field of view.  With this successful test, I can look at having a new eyeglass script made up for me that I can modify to fit this headband.  Of course, not having to use eyeglasses is easier, and I will need to get used to the actions of lifting and lowering the lens, but the gain of clarity of image is well worth whatever hassles using glasses presents.  I’ll post this latest lunar sketch in a separate blog entry.


Monday, 30 July 2018

Total lunar eclipse above Sydney, July 2018

Hi all,

This particular lunar eclipse presented a unique opportunity – to see the eclipsed Moon set behind the Sydney skyline.

It required some investigating to work out the best vantage points.  The angle of the line of sight window was a small one, and the landscape of Sydney’s east is also very hilly, AND the harbour also presents its own points and islands that can present obstacles.  What I wanted was a vantage point that allowed for a good view from the Harbour Bridge in the north and the city’s CBD to the South,

I could have the Moon set behind the gorgeous harbour bridge, but vantage points for this were limited and would mean being too close to the city for the sort of image I was after.

The area between the Bridge and the CBD is rather empty so I preferred not to have the Moon set here.

A vantage point was needed that would have the Moon set behind the CBD, and with any luck, it will set very close to Sydney’s tallest building, Centerpoint Tower.

So, at 4am I found myself on the foreshore of Sydney Harbour in the grounds of Strickland House.  Stickland House is a beautiful manor built more than 150 years ago, and has a gunbarrel view of the City down the harbour.   From here I had an uninterrupted view of the City skyline.  There was a risk that predicted cloud cover could ruin the event, but this only made things more interesting with an element of risk.

The photographic camera I have is not designed for long exposure work, so my intention was not to capture a textbook pretty photo of the blood red Moon.  But I brought it with me for the odd chance that I could manage a photo of the eclipsed Moon, but more for photographing the spectacular skyline at sunrise.   My main tools for the event was a modest Brinno time lapse camera, a sketch pad, oil pastels and binoculars.  I’d be happy with a nice little time lapse video, and a sketch of the event which would be a very different way to present the lunar eclipse.

As the eclipse progressed, I still hadn’t worked out what to do sketch wise.  Then it hit me – I have a gorgeous skyline in front of me, and why not a sketched time lapse too!?  I had done a sketched time lapse of Comet Lovejoy a few years back, so not a new concept to me.  What made it even more appealing to me was the changing appearance of the red illumination of the Moon as it progressed through Earth’s shadow.  The threatening cloud sitting behind the skyline would also add to the complexity of the sketch and add to the movement of the final piece.

I was not alone at the foreshore vantage point I set up on.  When I arrived a met three mates there who are photographers.  I set up next to Dan Chee from Delta Charlie Images ( ).  Dan’s welcoming nature made the cold so much more bearable, and with his mates for a very jolly one too!  Dan posted his spectacular images of the eclipse on his Facebook page.

The time lapse sketch also shows Mars which was just a little to the left and above the Moon.  This is why there are only three apparitions of Mars despite there being four of the Moon.  The two streaky lines are of a couple of planes that crossed through the field.

Oil pastel on black paper

As I had to wait for some time between each new position of the Moon in my time lapse sketch, I passed some of this time by doing a quick oil pastel sketch of the blood red Moon as viewed through my binoculars.  What made the apparition  so interesting was the difference of the density of the red across the Moon as it transited through Earth’s shadow.  It gave a wonderful range of hues across the lunar surface, and this suited very nicely the brisk sketching form in using oil pastels.  Oil pastels are not a medium for very detailed work.  They are an excellent medium for a fast Impressionist style of sketching.

Oil pastel on black paper

I’m also pretty happy with the modest little time lapse video of the eclipsed Moon.  Mars is also very easy to see.  The Moon makes its last apparition around the 57 second mark at it comes in very close to Centrepoint Tower.  And of course I forgot the camera was rolling towards the end of the filming.  Well, it was very cold by the end and I wasn’t thinking too straight! LOL

I hope you have enjoyed my little collection of images of this lunar eclipse.  To finish off, I’ve included a couple of photos I took of the skyline of my home city as the Sun began to rise.


Friday, 8 June 2018

Unique Planetary Alignment coming up in October this year!

Hi folks,

I've happened to have stumbled upon a very unique planetary alignment that will occur for a few days either side of October 18 this year!  All 8 planets, plus the Moon and Pluto will all be visible all at the same time.  This is one of the rarest planetary alignments visible!

Over the last few months I've started doing some sidewalk astronomy sessions, taking a telescope or two down to a popular spot along Coogee Beach near my home, and show people who are passing by a look at the Moon and any planets that happen to be visible on the night.  These sessions have been very popular with some people even calling their families and friends out from their warm homes to rush down to have a look at the Moon, Jupiter and Saturn! 😊

So, early this week I was doing some research for some future dates using an astronomy app that would be favourable in showing the Moon and planets when I notices something very interesting in October.  On the western horizon Mercury, Venus and Jupiter were all close together  soon after sunset.  It then occurred to me that Uranus might be up at that time as I was aware of its location in the sky.  Well, wouldn't you know it!  I shuffled the screen to show the eastern horizon, and there was Uranus!

This means that for a few days either side of October 18, ALL 8 planets, PLUS the Moon and Pluto will all be visible in the sky simultaneously!  All be it for only a few minutes, but all the major bodies in our solar system will all be visible at one time, and visible telescopically all within a couple of hours after sunset.  And from what I've been able to gather, this event has been totally missed by all major astronomical organizations.

This is an extremely rare event.  With the current position of the planets in their orbits, this whole of solar system event will occur on three separate occasions:

1st event will happen mid-October this year just after sunset, 2018.

2nd event will happen late April next year, 2019, just before sunrise

3rd event will happen late October and into early November next year, 2019, again just after sunset.

Then that's it for a few hundred years!

This alignment sees all the planets lined up all along the ecliptic from the eastern horizon all the way across to the western horizon.  The "ecliptic" is the plane around which all the planets travel in their orbits around the Sun.  Unfortunately this whole of solar system apparition will only last for a few minutes during each day that it is visible due to the position of the planets in their orbits.

Below are two screenshots from the Sky Safari app of the October 2018 event, with the location being from my home here in Sydney.  Please note that the screenshots below are for SYDNEY.  You will need to make the necessary adjustments for time immediately after sunset for your location.

Looking East on October 18 at 7:57pm

Looking West on October 18 at 7:57pm

Below is an image showing the relative positions of the planets at this time when viewed from above the ecliptic.

A linear alignment of all the planets and Pluto does occasionally happen, but with mean hundreds of years between events.  This linear alignment doesn't have all the planets perfect aligned, but the tightest clustering of the planets sees them spread out across 30° from the Sun.  The next such linear alignment isn't expected until the year 2854.

I will be endevouring to make a special occasion of this.  I'll be trying to organize some of my friends to join me with a few scopes to put on a planetary marathon, or a "Solar System Sprint" to bag all the major bodies in our solar system as quickly as possible, and to show all of these bodies to the general public.  I now have a reason to make an effort to chase down Pluto as well!  Prior to knowing about this event I've never had any interest to try to identify Pluto.  After all, it will only appear as a faint star in a field of other faint stars.  This very rare even now changes all of this!  I'll be starting to make observations with my 17.5" dob on a monthly basis of the area that Pluto sits in in order to pinpoint it by its movement against the background stars.  I'll also be doing this photographically from home as I doubt I'll be able to spot Pluto from my home because of light pollution.  It won't stop me from trying though.  I've already identified a magnitude 14 star that is easy to identify, and I have already pinned it with my video astronomy rig from home.  So I know Pluto with within reach of my video astronomy gear from my home.  If I am able to spot this same star with my 17.5" dob, then I know that Pluto is cooked!

Now, fingers crossed for a clear clear night some time on these dates!

Hopefully, you will be able to also enjoy this unique celestial event and attempt your own Solar System Sprint!


Monday, 4 June 2018

Steampunking an old telescope!

Hi folks,

Here’s something a little different.  With conditions having being so poor for so long, I’ve still been keeping my astro mind occupied with another project.

I have an older big 6” f/8 refractor.  For being an older achromatic refractor, it actually throws up a very nice image.  However, it isn’t a first preference scope for me.  It is just too big, too heavy and too bulky for my liking.  However, it is an excellent outreach scope, especially when there are other scopes around.  As a refractor is what most people consider as what “a telescope looks like”, at outreach this scope attracts people like moths to a flame.  Yet the purpose of this scope is in reality as a tool for making people aware that there are actually other telescope designs, and that these can be much more compact and others larger in aperture, and as people view through the different scopes on offer they will come to realize not only the differences between scopes, but that those “odd” looking “things” are actually better astronomical instruments than this refractor.

Yet the appearance of this big blue scope is lacking a certain “something”, a certain BIG scope look that early 20th century refractors had.  It occurred to me that this was a fantastic candidate for receiving the Steampunk treatment.

With this Steampunk treatment, there were a few things that the project had to accomplish:
·          *  Provide an exotic Steampunk appearance
·          *   Lots of brass and quasi electronic gizmos
·          *   Lots of lights as astronomical telescopes are mostly used at night
·          *   Not impede any of the functionality of the telescope
·          *   If possible enhance the telescope’s performance
·          *   Make use of the existing power source of the mount that the telescope mount’s uses.

So here it is!

The large focuser knob is completely functional and acts as a fine focus in the same way as the large focuser knobs that I made for the SCT’s of mine.

The long brass rod does spin a little wheel at the front end of the unit and goes over an LED.  This particular assembly is my brand new invention – BEHOLD! the “Alien Detector Device”!

The studded brown leather wrap is made out of kangaroo leather. 

At night, the exotic look continues with the use of 8 LED lights on the big unit, seven of which are flashing RGB.  The focuser knob also has a flashing RGB LED.

This project was a ball of fun to design, create and put together.  My Steampunking won’t stop here though.  I’ve come up with a design for my SCT that I’ve been wanting to transform for some time, but its stumpy shape presented a few design challenges that I’ve only just resolved.  I’ll also be giving my 8” f/4 solid tube dobbie the same Steampunk treatment.



Saturday, 12 May 2018

Jupiter - transit of Europa and its shadow animation

Hello everyone,

The day following my Jupiter sketch I revisited Jup’ and saw the last few minutes of the shadow transit of Io.  With this being essentially the time of Jupiter’s opposition, the gap between Io and its shadow on Jupiter’s disk is just about nil.  As a result it is actually very easy to spot Io against the disk of Jupiter when it is very close to the limb.  This really excite me, and I was keen to sketch the event when it repeated itself.

A couple of nights later (poor seeing conditions prevented any possible sketching), Europa was to transit across Jupiter along with its shadow.  The passing of just four nights was already enough to make the gap between the satellite and its shadow larger, but the effect was really just as intense and fantastic.

 As the transit of Europa started, it occurred to me that I could possibly do an animation of the event out of a series of sketches.  So, two and a bit hours later, I had a completed a sketch with the necessary details and time points that would allow me to prepare a series of twelve individual colour pencil sketches.

Below is the complete series of individual sketches from which the animation was made.

Normally for a high magnification sketch I would have used my 8” SCT.  This time however I used my 8” f/4 Kulali push-pull dob.  Its action is so smooth and easy that following an object at high magnification is very easy.

Object:  Jupiter with transit of Europa and its shadow
Scope:  8” f/4 Kulali push-pull dob
Gear:  5mm TMB Planetary Type II, 160X
Date:  9th May, 2018, 21:10 to 23:20 AET
Location:  Sydney, Australia

Thanks for looking,


Saturday, 5 May 2018

Jupiter - good conditions and a newer scope reveals remarkable detail

Hello everyone,

Well, after so long, I’ve managed reasonable seeing conditions to attempt a sketch of Jupiter.  Last year was a complete non-event with Jupiter as no matter when I looked at Jupiter, seeing was just terrible.  In fact, I haven’t managed a sketch of Jupiter in many years.

I do have to say that one big part of this was due to the old orange tube C8 I was using at the time just wasn’t up to the task.  In terms of focus, that old scope was remarkable and outstanding.  But she didn’t have coated optics, and being close to 40 years old, the optics were not as reflective as when new.  With the Moon this wasn’t an issue, but for planetary detail she wasn’t the best tool for the job.  The new SCT I’m now using, well, there is a big difference!  I am fortunate that the optics are also very good with this new unit, and I can pull outstanding detail with it at high magnification, but the optics are multicoated, and this has made an enormous difference for planetary detail and with DSO’s.

Well, it was good to have a break in the poor seeing and have the opportunity to not only pin Jupiter, but to also try a few illustration techniques I’ve been wanting to have a go with.

As with all my sketching, the longer I spend on a target, the more and more I see as time goes on.  Jupiter was no exception.  As clear seeing windows wafted through, these details revealed themselves as festoons, smaller pressure cells within the two main belts, a mottled structure within the fine bands, subtle colour variations within all the band structures, and most staggering of all was the significant hue difference and structural differences between the two main belts – something that I hadn’t noticed in photographs.  I've also noted the position of the four Galilean moons with just the first letter of the name of each.

Again, the best eyepiece for the night was my modest 9mm TMB Planetary Type II.  My 8mm LVW was just too much grunt, and the TMB just gave a longer and more frequent detail sweet spot as seeing came and went.  I also use two colour filters to help tease out details, a #80A blue and a #8 yellow.  The blue was excellent to tease out the Great Red Spot and the fine cloud banding. The yellow was especially helpful in highlighting the hue differences between the two main cloud bands and the subtle colour variations between the fine bands too.

The sketch at the scope was carried out using a good old graphite pencil on white paper, with a few notes added.  In the light of day I redid the sketch using a variety of coloured pencils on fine white paper – the fine texture paper is important in order to control the scratchy appearance drawing onto paper can have.  Once I was happy with the colour sketch, I cut out the disk and stuck it onto a sheet of the black paper I use for sketching the Moon, Sun and DSO’s.  I think I may need to improve my scissor cutting skills a little! LOL J  I am very happy with the final sketch construct as it gives a better rendition of what is seen through the eyepiece.

Thanks for viewing this piece of mine.


Object:  Jupiter
Scope:  8” SCT
Gear:  9mm TMB, 222X, #80A blue and #8 yellow filters
Date:  4th May, 2018 14:00hrs UTC
Location:  Sydney,  Australia
Media:  Colour and graphite pencils on fine white paper, cut out and stuck onto black A4 size paper.

Crater Humboldt - still so much to learn!

Hi all,

My golly josh!  It has been some 5 months since my last lunar sketch!  This summer has been terrible with astro weather.  Finally there’s been a break in the weather!  Woohoo!

I’ve been wanting to sketch the eastern limb of the Moon from just after the full Moon phase for a very long time.  It is really the only opportunity to sketch features that otherwise are only visible very soon after the New Moon phase, which is not practical being too close to the Sun and the sky is still too bright for good contrast in the image.  On this occasion, the phase was just one day after Full Moon.

It was like looking at the Moon for the very first time!  The whole eastern limb of the Moon is packed full of features that I hadn’t seen before!  It was quite a revelation for me to find out that there was a whole section of the Moon that I was totally unfamiliar with.

This night I took a different approach on what to select to sketch as I couldn’t decide between three or four different areas.   One particular big crater caught my attention, Humboldt.  What most caught my attention is the curious set of central peaks.  So, I looked up Humboldt on the net, and was met with a staggering image from the Lunar Reconnaissance Orbiter – the floor of Humboldt is riddled with a most regular lacy pattern network of riles.  I have never seen such a regular pattern in any crater.  Along with the curious set of central peaks, I was sold on Humboldt as being the center piece of my first lunar sketch in several months.

I was rusty, very rusty to start with.  Not having sketched the Moon for so long, I struggled a little at first to find my grove with the foreshortening and then the shading.  But I persisted and eventually things started to flow and happen a lot more easily.

I found this area quite intriguing.  Humboldt itself is an extremely old feature, yet it’s somehow managed to avoid too much damage over the eons.  Quite remarkable really considering its location so close to the far side of the Moon that has taken the lion’s share of impacts.  Being so close to the limb, and with the terminator just creeping away from the limb, the shadows of the craters, mountains, lone peaks and ridges all made for an outstanding scene and composition to tackle.

While researching this crater after completing the sketch, I came across the site for the Lunar Reconnaissance Orbiter.  The site contains some very high resolution images of Humboldt along with an explanation for the cause of very curious pattern of riles.  As it turns out, these are fracture lines caused by the subterranean magma pressure causing the floor of Humboldt to dome.  From the LROC photograph below, one can see that the pattern of fracture lines is of-center to the geometric center of Humboldt.  This is because the crown of the dome is not centered either.

LROC image.

This sketch was a lovely way to blow the cobwebs out and get back into the grove of some sketching.  Fingers crossed it won’t be another five months until the next!

Object:  Crater Humboldt and surrounds
Telescope:  8” SCT
Gear:  9mm TMB, 222X
Date:  1st May, 2018
Location:  Sydney, Australia

Until next time,

Clear skies and sharp pencils,


Tuesday, 17 April 2018

Jazzing up Open Clusters

Hi everyone,

This year has been very lean pickings.  So my apology for the poor frequency of posts.

Of all the deep sky objects, open clusters have proven to be the most difficult to lay down in a way that conveys the sparkle that we see through the eyepiece.  This has been the main reason why I’ve avoided sketching them.

This last Sunday, the sky for once was remarkably clear hear at home, despite the warm day and smoke from major bushfires happening in southern Sydney.  With the Southern Cross being high up early in the evening, I thought it would be a good opportunity to experiment a little with some open clusters and trying to work out some ways to add that sparkle.

There are two magnificent open clusters that are bright and spectacular.  IC 2602 is also known as the Southern Pleiades, is very bright and large cluster just south of Eta Carina.  IC 2606 is just over 1.5° in diameter.  NGC 4755, the Jewel Box, is a gorgeous bright and compact cluster in the Southern Cross.  Its name comes from the lovely colours of white and red that can be seen in the component stars.

I sketched each in turn and photographed each before attempting some jazzing up techniques.  Through the eyepiece, these are quite spectacular clusters.  Being located in the band of the Milky Way, there is a certain background glow that goes to brightening the background, and adds to the pizzazz of the image.  The longer you spend looking at these clusters, the more and more stars you begin to make out as your eye adapts to the view.  It really is quite amazing.

So here are the two clusters.  And as always they appear as just dots on a black page…  <sigh>

Now, how to give some lift to these?

I’ve tried two techniques here.  The first is a very soft application of soft pastel dust to the cluster (Jewel Box), or around the individual component brilliant component stars (Southern Pleiades).  Ok, a little better, but still not enough.  Next, I added something I rarely ever use – the dreaded Ring Of Death… a field of view circle.  Yet this alone isn’t enough to convey the glow that is seen through the eyepiece.  So here I added another soft dusting all around the inside of the field of view circle, being careful to make it fade out coming into the field of view and not be too wide.  The idea here is to lift the overall image as it appears through the eyepiece, but not make too much impact on the cluster itself.  The trick being in the control in application of the dust around the circle.  The application of the dust on the cluster itself also needs to be very careful or it could come across as nebulosity instead of a wee lift in overall brilliance.

So, what do you think?  Any suggestions?

Difficult to convey through digital media, but hopefully the differences can be noticed.

Object:  IC 2606, The Southern Pleiades                         Object:  NGC 4755, The Jewel Box
Telescope:  8” f/4 push-pull dob                                       Telescope:  8” f/4 push-pull dob
Gear:  24mm 82° eyepiece, 33X                                       Gear:  10mm 70° eyepiece, 80X
Location:  Sydney, Australia                                             Location:  Sydney, Australia
Date:  15th April, 2018                                                      Date:  15th April, 2018

Thanks for looking,


Sunday, 4 February 2018

Dew Control With Astronomical Sketching

This has been one of the most confounded exercises for astro sketchers.  There have been lots of ideas, but few effective solutions.

For any solution, there should be a set of criteria that needs to be met:

·       *   Simple to make
·       *   Simple to use
·       *   Modest in power requirements
·       *   Be effective in keeping paper dry

Not an onerous set of requirements, but these have proven difficult to achieve.

This article will describe my experiences with dew and sketching, and the three solutions I’ve found that have proven most effective in controlling dew during my astro sketching sessions.  As they say, “necessity is the Mother of invention”.  Sometimes however, these solutions can have flippant origins!

Avoid dew to begin with!
The easiest solution requires no specialized equipment at all.  Careful site selection can provide an environment that is dew free in the first place all night long.  Dew and astronomy DO NOT need to be inseparable bed fellows.  It is possible to actually find locations that are dew free.  It does require knowing what to look for in the first place, and then to use this knowledge to finding the site.  A big grassy field is actually the WORST possible situation for any astro activities.  Grass means rich moist soil, and at night moisture saturation is quickly achieved with water vapour being released by the grass itself and from the soil, and dew settles very quickly as it is denser than air, and everything becomes very wet very quickly.  There are even some popular astro sites that have had no appropriate site selection processes carried out to fully determine the location’s suitability for astro activities.

However, it is possible to find dew free locations, if only being seasonal.  The dark site locations my observing bubbies and I use have been painstakingly vetted for exactly this purpose, and these 19 times out of twenty are perfectly dew free during our dark sky sessions.  On those rare occasions when dew does form, it also means that transparency is not as good as it can be, and usually we end up packing up early.

That’s another thing that dew affects.  The increase local water content in the air also reduces transparency.  Finding a dew free location has many more added benefits than just no dew – it also brings with it improved transparency, and it can also bring improved seeing depending on the local geographic surrounds.

You will find information on how to start looking for dew free locations in an article I wrote on the topic:

Dew shield solution
However, sometimes dew is unavoidable, no matter what we do.  I have been able to deal with modest amounts of dew with the very first sketching rig I made.  My first solution followed the simple “dew shield” principle and I created an awning that wraps around the sketch rig.  Very simple and effective as dew tends to fall around the paper largely without making the paper damp.  This awning also provides a great location from which to perch the lights by which I sketch. 

The location of the light source is also extremely important.  The worst location for the lighting is on top of one's head!  With the light being square to the paper, the reflected glare that comes off the paper goes wholly into one's eyes!  By having the paper being illuminated from the side, whatever glare there is is reflected straight off the side, and an absolute minimum of glare is reflected into one's eyes.

Fans and localised evaporation
Yet this initial simple solution has its limitations.  When the sketch exceeds A3 in size or when dew is particularly heavy, the simple awning just doesn’t provide enough protection.

I encountered this when I made my second sketching rig to accommodate a very large sheet of card to sketch the Large Magellanic Cloud.  The first night I used this rig, dew was very, very light, but the absorbing properties of the paper meant that it became damp very quickly, despite the larger awning I made for the rig.  I had to find another solution or this sketch would be impossible to do.

Using fans to cool and control dew on telescopes is very common place, and when implemented correctly can be extremely effective.  I had several 4” 12V fans at home that I had accumulated over the years as part of experiments with my scopes and from cannibalising them from old computers.  Running out of time and options, and having nothing to lose, a somewhat flippant idea came to me to install a couple of these fans to the top of the sketch rig.  To improve airflow efficiency and flow direction, I enclosed the fans with some thin black foam rubber.  For this initial iteration, I connected the fans in series.  Using a 12V power supply, this would mean a slower fan rpm rate, but I had to start somewhere.  If the initial testing proved positive, I could always reconnect the fans in parallel to increase the fans rpm’s and increase airflow.

Finally, the night came when dew was problematic, with my paper becoming damp very quickly.  I had no alternative but to switch on the fans and see what happened.

WOW!  These fans were so very effective!  Not only did they stop dew from dampening the paper, but they also dried out the damp that had already been absorbed by the paper!  On this particular night, EVERYTHING became wet from dew.  Our cars, telescopes, the ground, even my headlamp.  Yet the modest rpm’s that these fans were working at proved totally effective in keeping my paper absolutely bone dry.  It would have been impossible to work for three hours on the sketch that night if the paper wasn’t kept dry.  Damp paper leaves the paper very fragile and impossible to work with.  Just think of attempting to write on damp newspaper – an impossible task without causing damage to the paper, no matter how careful one is.

One other solution
Some people have suggested making a heated sketch pad.  The biggest problems with this is it means a huge power requirement that only gets larger as the sketch pad becomes larger.  It also means a more complicated fabrication, and it is not cost effective, nor simple to use.  I quickly discounted this as a viable solution.

This has been my journey so far in finding an effective dew control rig form my astro sketching.  When a sketch at the eyepiece can take anywhere between half an hour to nine hours, I really need to be able to have an extremely effective way to prevent my paper from becoming damp.  I now have three solutions – a dew free observing site, a simple awning reaching over my paper, and a fan powered sketching rig.  I hope this has given you some solutions and inspired so ideas for you to explore in your own astro sketching journey.