Sunday, 4 February 2018
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.
Tuesday, 30 January 2018
Well, it’s taken close to a year, but I’ve finally managed to complete this HUGE sketch of the Large Magellanic Cloud for Prof. Renée James! AND I found a system that helps keep my paper DRY during dewy nights!
First the weather conspired to prevent any chance of an early completion, by which time the LMC season had finished. I had to wait until November last year for the new LMC season to begin, and the weather AGAIN delayed any chance of a favourable sketching night until two weeks ago. I had left the sketch last year with the majority of the nebulosity laid down. I then had the opportunity in mid-January for two crystal clear nights in which to complete the task.
If you recall, I had constructed a sketching rig especially for this size sheet. The size of the sheet I used with this sketch measures 510mm X 635mm. To the top of this rig I attached a pair of 100mm fans which I connected in series and runs on 12V. I attached the fans more only because I had them and I thought I had nothing to lose if I try this idea. On the second night of the sketch, conditions were very clear, but the easterly breeze that was blowing in from the coast meant that dew was forming a couple of hours after sunset, and my paper was beginning to dampen. So I turned on the fans. To my great surprise, the fans blew dry the damp and kept the paper bone dry the whole time I was sketching, while everything around us was getting soaked with dew!
I am absolutely overjoyed at this dew control find! Sketching in dewy conditions has always been a problem for me, and I just abandoned the exercise as it is impossible to work with damp paper. This system that I rigged up on a dumb whim of speculation proved to be the champion I needed to keep my paper dry and me working! If it were not for this sketch, I would never have found this solution. Thank you Renée!
As I had the fans connected in series, each fan was effectively running on 6V, and their spin velocity was lower than if they were running on 12V. Yet this air flow was plenty to dry off the paper and keep it dry. Connecting the fans in parallel would give me greater air flow, which could be advantageous when dew is very heavy, but at the same time, if dew is this heavy transparency would also be greatly diminished and less than ideal visibility. But it is something to consider and explore.
The sketch I have to say I am greatly relieved that it is done. The sketch presented serval technical challenges that I had to constantly keep on top of. The scope I used was a 100mm f/5 achromatic refractor with a 30mm 82˚ eyepiece giving 17X magnification, and a true field of view of 5˚. The LMC measures some 12˚ X 12˚, no less than 6 times the diameter of the full Moon, and nearly 3 times the true field of view given by my scope/eyepiece combination. The single biggest challenge was maintaining the scale of the piece and the relative positions of the stars to each other. Another challenge was keeping track of the different landmarks so I could position the different features in their correct position, stars and nebulosity the same.
There was another revelation that I found, though not as a result of this sketch, but of something else I’ve been thinking about – illumination of my work.
I REALLY dislike red light. It is synonymous with astronomy the use of red light, but the reality is that the use of red light in astronomy is entirely a throwback to the old dark room days when red light was use to process black and white photographic prints. The problem with red light is our human eyes are not great in making out detail when the only source is a feeble red light. To make out any detail, such as reading a chart or finding something in your kit bag, the brilliance needs to be increased and increased and this begins to stuff up your night vision. I for one really struggle to read my charts under red light, and my smartphone I run with the full colour display, not the “red light display”, as it is impossible to effectively read a dimly illuminated red coloured screen. Red is a lousy colour for our human eyes to register contrast with.
Yet, if we slightly shorten the wavelength of the light we are using, we can reduce the brilliance of the light, gain a marked improvement in contrast when reading, and not compromise our dark adaptation – this was the thinking I had, and there was only one way to prove this, by trying it out.
The size of this LMC sketch meant that I was positioned further away from the paper than I would be otherwise. Making out the pinpoints of the stars I was laying down with red light was impossible to see – all because our eyes are poor in making out contrast under red light. I had no choice but to try out the amber light.
What a difference it made, instantly! These amber LEDs are less brilliant than the red ones of the lamp I use for my sketching. Yet I was able to easily and clearly make out EVERY pinpoint I was marking on the paper. As for my dark adaptation and perception through the eyepiece? No issues whatsoever! I experienced no diminished dark adaptation at all. Instead, because the light I’m using is now less brilliant, I have noticed my eyes are less stunned, and this only improves my seeing.
I will be writing a separate blog entry about the use of orange and amber lights. There I will discuss in more detail the problems of red light, and the improvements that there are to gain by changing our mindset of “red lights only in astro” to instead a mindset that better takes into consideration our HUMAN eyes and the ways that we can better work with them instead of against them.
Once the work out in the field was completed, at home in the light of day I tidied up the sketch and touched up the piece to add those infinitely tiny and impossible to individually lay down tiniest of stars that as a whole lend their light to the overall visual appearance of the LMC. I used the same “machine gun” device I use with globular clusters to give the necessary lift and life to the LMC. Without these the sketch remains flat and lacking the necessary brilliance seen through the eyepiece. I’ve added a close up of the bar and Tarantula nebula section to show this detail that the whole of sketch photo just cannot reveal.
So, here it is. My rendition of one of our closest intergalactic neighbours, the Large Magellanic Cloud
Scope: 100mm f/5 achromatic refractor
Gear: 30mm 82˚ eyepiece (17X, 5˚ TFOV), broad band nebula filter and OIII + Hbeta hybrid filter
Location: Blackheath, NSW, Australia
Date: over three nights spread out over a year
Media: White soft pastel, charcoal and white ink on black card (510mm X 635mm)
Duration: 9 hours at the eyepiece, plus four more hours tidying and finishing off at home.
Close up photo of the bar and Tarantula Nebula area showing the fainter machine-gunned stars that give the sketch the necessary lift and life seen through the eyepiece.
A final revelation came to me about the LMC while I was examining a photo of it by Marco Lorenzi. A fantastic resource about the Magellanic Clouds is the brilliant website Clouds of Magellan:
It contains very detailed charts of these galaxies, and offers other resources such as links and even sketches of the Clouds and of objects contained within.
The LMC is classed as a dwarf barred spiral galaxy. The bar is very conspicuous when viewing it naked eye from a dark site. The arms are however not noticeable, instead we see these as lobes on either side of the bar. Even the majority of photographs fail to capture the structure of the arms, instead the over processing of the photograph washes out any trace. Yet I noticed something very special about Marco’s photo when I was comparing it to my sketch. The arms of the LMC are actually visible in both Marco’s photo AND my sketch!
What is additionally revealed here is that the arms are not perfectly symmetrical, as would be expected, because of the significant influence of the gravitational tidal pull of the Milky Way on the LMC.
Yes, there is a magnificent barred spiral galaxy right over our heads, with two sweeping arms that wrap themselves around the whole structure. Yet, while most of us may know of the spiral classification of the LMC, very few of us are actually aware that of its true magnificent structure, mainly because of over processed photographs, and of very few sketches of the whole galaxy. Marco’s photo is orientated in the same direction of rotation as we see the LMC directly overhead. The LMC is rotating in a clockwise direction when you view it naked eye. Due to the left-to-right flip of the image with a refractor, the LMC in my sketch it rotating anti-clockwise.
You will find Parts I and II of this project in the links below:
This sketch has been one big undertaking. From the start I was aware I had to do a lot of prep work to get to terms with the size and complexity of the LMC. From a new sketching rig to accommodate the larger sheet, to the provision of a dew control system (if initially only experimental, but ultimately successful), and the need to adopt a different colour of illumination. Then there were the technical challenges out in the field beside the eyepiece and the challenges crappy weather posed. Finally the revelation of the true whole appearance of the LMC above our heads.
I sincerely hope that this sketch, and my experiences that came with it, serve to INSPIRE you, not intimidate. I hope to inspire you to pick up a pencil. Inspire you to not be shy about tackling the seemingly impossible. And to inspire you to challenge yourself and explore different ways of thinking not only about sketching, but of how we go about doing our astro thing in the dark.
Clear skies and sharp pencils,
Thursday, 14 December 2017
With the horrid run of astro weather we have had here in Sydney, I've had to keep myself busy with other astro projects to keep my hands occupied. So, it became the perfect opportunity to revamp a flawed little scope, and transform it into a brilliant performer!
I’ve had this 130mm Celestron Astromaster scope for a little while. The single biggest problem with it is the poor equatorial mount it comes with. The mount is too wobbly, and really more of a pain in the neck than what it offers. And for beginners, this mount is the single biggest frustration that leads to this and similar scopes being put away and never used again.
The finder bracket on this scope had also broken off. I am not too sorry about this as the original finder it came with was rubbish too. Too close set to the tube made using it difficult, and its design is not easy to use.
So, the solution to this scope to give it a new lease on life is to ditch the eq mount and make a new table top dobbie mount for it, and install a better red dot finder to it.
I went to town on this little scope! I had some fine materials left over from some other DIY projects, so I was able to use the following stuffs:
· * 15mm marine grade plywood
· * Ebony Star laminate
· * Teflon bearing pads
· * Marine grade varnish
· * Stainless steel azimuth pivot bolt and washers
· * And a brand new 20mm red dot finder on a dovetail block.
Many dobbie mounts, including table top designs, do not have a balanced Optical Tube Assembly (OTA). This means that if you switch between a wee little eyepiece to a very heavy eyepiece, the tube become top heavy or tail heavy when you switch back. So these mount have a friction mechanism by which the altitude bearing is tightened, and there by making action of the altitude bearing stiffer so the tube does not drop under a heavy load. Biggest problem with this being the quality of the action of raising and dropping the scope not only becomes harder/stiffer, but it makes tracking a target at high magnification as the action becomes jerky and very difficult to control.
Not with this little scope!
I designed the mount without any friction mechanism, but the OTA is perfectly balanced and the mount allows for the OTA to be loaded with any size of eyepiece, and the scope does not drop or rise – it stays put and the quality of the action not only remains exactly the same all the time, but it is silky smooth ALL the time!
This little scope now is a red hot, stable and very user friendly instrument. I can swap eyepieces and the tube does not shift, even with no eyepiece in the focuser. I can more easily locate targets because of the higher set red dot finder, and I can easily keep track of targets no matter the magnification I am using!
Wednesday, 13 December 2017
I've added a new links gadget to my site in the right hand side margin - Sites and Blogs of fellow astr-sketchers and other astro-sketching resources. It is dedicated to the websites and blogs of fellow astro-sketchers and other astro-sketching resources.
I've started on a journey to find as many fellow astro-sketchers, and add their sites to the listing. Different artists use different media, some pencil and paper, others soft pastels and black paper like myself, others work with digital processes, and many other different materials and media. Astro-sketching though a very small niche, there is a wide variety of media, materials and techniques being used. By adding the sites of as many astro-sketchers as I can, I aim to give exposure to all the different ways people illustrate and fulfill their passion for astronomy and sketching in its many forms.
There are a few people who cannot view into their telescopes due to physical limitations, so they use electronically assisted methods, such as video astronomy, to produce an image on a monitor, and they then make a sketch of what they see on the monitor. Technology now provides a means of allowing a wider audience to participate in astronomy, and gives them tools by which to facilitate their own passions within astronomy and art that prior to this technology being available these people had no way of doing so. Marvelous stuff!
If you know of a site that I have not listed, PLEASE let me know of it!
Please explore the work of these fellow astro-sketchers. They all offer a different take on their art, different experiences and different approaches.
Wednesday, 22 November 2017
This really has been a miserable astro year for me and all of Sydney for that matter. We may have sunny days, but the evenings are cloudy or windy or seeing is just the pits. Yet we amateur astronomers are an optimistic bunch, and opportunistic if need be.
Yesterday was another one of those sunny teasers. Few clouds all day long, and sunset saw the clouds disappear! But this was just a tease. On the horizon there was an ambush of rainclouds waiting for the final rays of the sun to disappear to mark their charge upon the Sydney sky.
Expecting this, I had a quick look towards the west as a very thin waxing lunar crescent was low in the sky and close to Saturn. The Moon just proved irresistible, and a huge urge to sketch the gorgeous scene had me thinking – “Do I have enough time? Can I get the gear together fast enough and smash out a sketch before the Moon dips too low and beat the impending rush of cloud cover? Shall I chance it? YES!”
In two minutes I set up my ED80 refractor, and four minutes later again I had my pencils sharpened and sketch pad in hand. A quick compass scrawl of an incomplete circle for the outline of the Moon, off-set for composition value, and then started the mad rush to get as much detail down as possible. The Moon was no more than 30° above the western horizon and dropping fast. In my favour was surprisingly stable seeing over what normally is a very warm and shimmer laden western sky. And as always, the more I look the more detail I see. But there’s no time! The leading charge of clouds started moving in, taunting me as the Moon was briefly obscured. No time to pause. What can I see through the haze that I can lay down in the sketch? MOVE IT! Alex! Keep it neat! Don’t dawdle. MOVE!
And in half an hour it was done, and the Moon disappeared behind clouds right on que!
What a rush!
With the crescent done, I just filled in the Earthshine with a paint brush using soft pastel dust and tidied up any loose markings along the limb. Finished.
I am really happy with this piece. The composition works really well being off-set, and that some of the Earthshine part is cut off works too as goes to make the crescent the focus of attention. It has a certain 3D feel to it, like you are passing by the Moon on your way to another destination. I hope you enjoy this piece too.
Object: 4 day old Moon
Scope: ED80 refractor
Gear: 9mm TMB Planetary Type II, 72X
Date: 21st November, 2017
Location: Sydney, Australia
Media: White soft pastel and charcoal on A4 black paper
Monday, 11 September 2017
There’s one variety of solar prominence that I’ve been wanting to see for a long time. Even from before acquiring my first Hydrogen Alpha telescope. Coronal Loops.
I’ve been starved of any form of solar observing for a long time thanks to the terrible run of poor seeing conditions that have persisted over Sydney for several months. Even just at 50X magnification, the image of both the Sun and the Moon are unbearably shimmering. Yesterday I took a chance on a break in conditions, and boy, I was richly rewarded!
My first peak through the eyepiece saw my jaw hit the ground, and I started “Yahooing”! Coronal Loops! A big cluster of them too!
This is where another part of my fascination with astro kicks in. I did not know the name of this type of prominence, so if you don’t know something, you ask. I sent a text message to a fellow solar buddy of mine, Ivan, about the fabulous apparition. He was also kind enough to enlighten me on the association that these proms come from.
These are a rare prominence type, associated with highly volatile Active Regions on the Sun’s surface. Here, very high temperature plasma (atoms that are so hot they have been stripped of their electrons), is electrified and is racing along magnetic fields. These magnetic fields are also connected to areas containing Sunspots. Sunspots are a common feature on the Sun’s surface. However, Coronal Loops are not always present. They are only seen during periods of high activity, particularly during the Solar Maximum.
The Sun has been very subdued for a time, with very little prominence activity. These last few days has seen things take a major turn with not only several prominences appearing, but the Coronal Loops indicate a burst in activity.
This first sketch shows a complex set of Coronal Loops, erupting from several points.
Today, Ivan sent me a message to bust out the solar scope again. I couldn’t resist the suggestion. The Coronal Loops cluster had changed in appearance, and I just had to sketch this new apparition. There’s also two sets of sun spots that can be seen towards the bottom of these first two sketches. It can be seen the difference in the position of these two sets from one day to the next, indicating the rotation of the Sun during the 24 hour period.
The circumference of the sun was riddled with hedgerow proms, pillars, detached proms, pyramid proms, spicules, inclined proms, and one massive eruption. Along with the extraordinary Coronal Loops, the entire scene just demanded a sketch of the full disk – something I had not done before.
For my prominence sketches, I use a Quark Prominence filter on an ED80 refractor. While this filter is exquisite for prominences, details on the chromosphere are not particularly evident. These details are still there, but they take some doing to tease out. To help me tease out these details more easily, I use a little PST. This little scope allows me to quickly identify where significant chromosphere and then I use the Quark to pull out more detail from these specific areas. This way I was able to more easily identify where several filaments were, and another Active Region around a small group of sunspots.
It has been quite a wonderful return to solar sketching these last couple of days. From nothing for several months to three pieces that filled me with excitement. From very little solar activity, to a spectacular set of Coronal Loops and a massive eruption and an amazing collection of different prom types.
I hope you enjoy these three pieces too.
Thursday, 11 May 2017
It has not only been a long time since my last DSO sketch, it’s also been a long time between lunar sketches too.
One thing that’s kept me in touch with my scopes has been making bits and pieces for them. One has been the new case for my SCT that I posted a few weeks ago. I’ve also changed the secondary holder and spider of my 17.5”. I’ve now also modified the large fine focus knob I made for my SCT.
I made a large dial knob for both my old orange tube SCT and one for my new instrument. However, just making the same thing all over again left me feeling a bit ho-hum about it. It lacked a little bling. So, after a friend asked me to make a new pimped up dial for a controller of a scope of theirs, I went to town on mine! It looks like a 19th century time machine exploded all over it! As some of the gears have a lot of height to them, I first had to make sure that the position I put them in did not interfere with the operation of the scope nor with stowing it. This Steampunk treatment complements the timber of the knob, and has given me ideas on how to possibly give the Steampunk treatment to the new case for this scope. I also have a few old glass electronic valves that I can use for this exercise.
This week also saw the lunar drought break for me with two sketches! Hooray!
Sunday night proved to be the break of the drought with a gorgeous clear night. My initial examination of the Moon threw up two great sketch candidates. One was around the elongated crater Schiller that I’ve been wanting to pen for some time. This area is very busy. The other area was around Aristarchus, with the sun just illuminating its rim edge, and a more gentle area of smoother Maria. Not having sketched the Moon for so long, I felt very rusty and in need of getting my eye in again before tackling something like Schiller. Also, with seeing not being too flash, I felt that I would struggle more with a more detailed crater ridden area compared with a more smooth plain area.
Dawn Rising Over Aristarchus proved to be a most enchanting piece. The flat maria lunar surface is rolling back around the Terminator, giving a lovely 3D effect, and the shadows cast by the nearly totally flooded crater Prinz and a series of lone mountains next to Prinz, made for a wonderful juxtaposition between light and shade, giving a lot of drama and precious detail to the piece.
Object: Dawn over Aristarchus and Oceanus Procellarum
Scope: 8” SCT
Gear: 9mm TMB Type II, 223X
Date: 7th May, 2017
Location: Sydney, Australia
Media: Soft pastels, white ink and charcoal on A5 size black paper
Drygalski and Mountains During Full Moon was done a couple of nights later on the Wednesday that followed. Smack bang in the middle of the Full Moon phase!
I LOVE the full Moon! LOVE it!
Most astronomers wouldn’t even think about hauling out a scope during the full Moon. Me, I see it as the perfect time to spot one of the most striking features on the Moon itself, its mountains and lunar scape seen from profile, instead of just from above!
Most people think that there are no shadows to be seen during the full Moon. Not so! The only time that there would be no shadows visible is during a lunar eclipse, which is the only time that the sun’s rays fall perfectly perpendicular on the Moon to us. But as the Moon most often orbits the Earth above and below the Earth’s orbital plane, some degree of shadows been cast will always be seen. And the full Moon phase allows for a most extraordinary display of shadows cast over hills, rolling plains and behind mountains. A most extraordinary sight.
I have sketched Drygalski before. However, libration of the Moon had it in a much more favourable position that first time, with the crater floor visible then, but totally black filled this time. It and every other crater is VERY squashed and elongated due to foreshortening. And as the scene is such a wonderful field, I had to sketch this spot to a much wider size.
Object: Crater Drygalski and Mountians during the Full Moon phase
Scope: 8” SCT
Gear: 9mm TMB Type II, 223X
Date: 10th May, 2017
Location: Sydney Australia
Media: Soft pastels, white ink and charcoal on A5 size black paper.
Two widely different scenes, one Moon.