Astroblog

My first sighting of Comet C/2012 F6 (Lemmon) using 10x50 binoculars (click to embiggen). Seen from my back yard. Sadly most of the local light pollution is to the South, where the comet is.

I sketched it because none of my cameras are up to the kinds of exposures needed for comets (also, the light pollution would overwhelm my cameras). The sketch is a little rough because the Bettdeckererschnappender Wiesle has my red torch, so I sort of did it in the dark.

I'll drag out the telescope tomorrow, if the weather holds.

Labels: binocular, comet, comets, sketch

Jupiter sketched through my 50 mm unguided refractor (Alt Azmithal mount) on the nights of 15, 16 and 19 January	Jupiter as predicted by Stellarium (images inverted as my telescope inverts the image, and Stellarium doesn't in Alt AZ mode)

As I've mentioned before, the latest panic du jour is that Jupiter and Saturn are mysteriously tilting. David Greg has been imaging Jupiter, but I thought I'd present some of the sketches I did while on holiday down the coast.

For travelling, I use the little 50 mm refractor that I got when I was a teenager, it has an old and somewhat cranky alt/Az mounting, but it fits nicely in the back of an overloaded car and is good for the Moon and planets.

Since getting my webcam cameras set up and getting the digital camera adapter, I haven't done any sketching or about two years, so it was good to get back into it. Unfortunately, when sketching at home I have a red light torch to illuminate my note book, and a comfortable chair to sit on. This time I had to sketch on insolated sheets of paper in the semi-dark while crouching uncomfortably over the eye piece.

However, despite these limitations my drawing pretty closely match the predicted Stellarium position for Alt/Az mountings (when flipped because my telescope inverts the image, and Stellarium doesn't when in Alt/Az mode). I didn't look at the predictions until after I had made the sketches (at the very least because my computer with Stellarium on it was an hour and a half away).

So, no planetary pole flip.

Labels: Jupiter, Pseudoscience, sketch

Right: Sketch of Vesta near gamma Leonis on the 6th and 7th of February (Vesta indicated by a "v"), Left; Skymap Pro chart of same area.

While Mars is hogging the limelight at the moment, asteroid Vesta is heading for opposition later this month. As Vesta is near Gamma and 40 Leonis, finding it in binoculars is very easy (and Vesta will pass between gamma and 40 Leonis later in the Month too, a very interesting sight).

Since my webcam based imaging system isn't really up to faint stars, I've been sketching through binoculars. My sketches haven't turned out too badly, and the positions of stars and Vesta are pretty good considering I'm just holding my pad (size differences due to my binoculars having a smaller field of view). Some of the stars appear "double", but thats me just trying to darken up the dots, and missing the original in the dark. I can make out stars down to magnitude 9 through the binouclars on a bark night under suburban skies!

Anyone else sketching or imaging Vesta can send me their images if they like and I'll put them up here.

Labels: asteroids, Observational Astronomy, sketch, Vesta

Left Image: Mars as sketched through my 4.5" Newtonian Reflector. Right Image: Mars earthward facing side at the same time as I was sketching, via the JPL Solar System Simulator.

The opposition of Mars for 2010 was last night. It was never going to be an auspicious opposition, Mars having the smallest diameter since 2003 and the opposition being in Summer here, Masr never gets far above the horizon, where murk and turbulence interfere with viewing.

Given that it was 36 degrees C during the day, and still 25 degrees in the middle of the night, turbulence was going to be a big problem. Also given that it was eldest sons bithday party (he is a prime number old, which is the sum of MiddleOnes age (an even number) and half SmalestOnes age (his full age is an even number and half is age is a prime)) with kids rushing around it was not going to be a good time to get out Don the 8" Newtonian and my astrophotography gear.

Still, I was able to get out my unguided 4.5" Netwonian and combine my youth watching duties with observing the red world. I even got the kids to have a look at Mars, the "Blue" Moon and Saturn.

Despite the viewing being shocking, through my 6.5 mm Plosell lens the bright white polar cap was clearly visible. There were also sufficient moments of stillness where I could see some darker markings, and I got them down. Satisyingly, despite the conditions my sketch is in good agreement with the surface marking that were visible at that time. Not bad, seeing as the smaller circle in my sketch is approximately the size Mars looked like through my 6.5 mm lens.

Mars will still be good for most of February, so why not get out and have a look?

Labels: Mars, Observational Astronomy, Opposition, sketch

How was your day 3 of the 100 hours of Astronomy? Mine was largely clouded out. In the spirit of Galileo's 400th anniversary of looking through a telescope, and in the sprit of doing alittle more than just looking up, why not do some sketching? The Moon is bright and is showing plenty of craters, so this is a good time to sketch the Moon.

All you need is a paper some pencils and, say a pair of binoculars. Galileo's scope wasn't much more powerful than this. It can be a bit difficult to hold binoculars and sketch at the same time, so use the back of a chair or table to stabilise the binoculars. Have a go, you will see how much fun it can be!

100 Hours of Astronomy - Day 1
100 Hours of Astronomy - Day 2
100 Hours of Astronomy - Day 3

Labels: International Year of Astronomy, Moon, sketch

You may be familiar with red/(cyan or blue) anaglyphs. These are pictures where a 3D effect is produced by overlapping red and cyan (or blue) images. I have used anaglyphs to make stereo images of Mars and the Sun, for example.

A couple of days ago MiddleOne asked if you could draw 3D pictures. I thought it was possible from my experience with anaglyphs, and we experimented with various coloured textas, but with only minor successs.

Around 5:30 this morning SmallestOne kicked me out of bed, and I started thinking (or maybe I was already dreaming) about anaglyphs. I couldn't go back to sleep, so I tried experimenting. First you need the right colour textas. Our stereo glasses have red for the left eye, and cyan for the right eye. You need a red colour that will be invisible through the left eye, and dark through the right eye, and a blue/green that is invisible through the right eye and dark in the left eye.

It was pretty easy to find a light red text that fitted the bill (our previous attempts had used too dark a red). Finding a blue-green that worked was much harder, and I had to settle for a pale green/blue that sort of worked.

Once you have your colours, then how do you match them up to give depth? I started with simple squares. Blue-green lines to the left of the red lines make the boxes appeare below the picture plane, blue-green to the right makes the boxes appear above the picture plane. The wider the lines apart, the greater the feeling of depth. by grading the line spacing, you can give a feeling of volume to the surface.

You also have to choose your viewing postion, straight up and down at about a meter away works best.

The planet with craters and rings above is the result. Viewing with red/cyan glasses about a meter away gives a nice 3D effect for the cratered body of the planet. The rings are a little wobbly though, but still, this was a hand drawn image using only red and blue-green textas. A little practise (and a better shade of blue-green), and you can draw stunning 3D images without fancy computer graphics programs.

Labels: sketch, stereograms

In this time of webcams and affordable CCD cameras, we tend to forget that sketching is a simple, portable way of recording astronomical objects, especially planets. Sketchbooks don’t require cables, batteries or power cords. They don’t care which operating system you use, or whether you have RS232 or firewire ports. They can still be read decades later, long after the current electronic storage systems are obsolete. You also don’t need a big telescope system.

My first astronomical sketches were of the Moon, done through my Dad’s binoculars resting on my window sill. I’ve been sketching stars, planets and comets for years using a 115 mm reflector with no tracking. Almost anyone with an entry level telescope can sketch the Moon, Jupiter, Saturn, the later crescent phases of Venus and Mars at opposition. I even have sketched the sky as seen by my unaided eye to record movements of comets and planets.

On the other hand, making sketches does require some minimal form of manual dexterity. Still, sketching planets and stars is an entirely different proposition to drawing the Mona Lisa, so if you can set up a telescope without tangling yourself in cables, you should be able to produce a satisfying and workable sketch.

As with anything astronomical, a little preparation repays dividends at the telescope. Most people keep observing logs; it is very simple to combine an observing log with a sketch book. I use semi cartridge 110 gsm acid free drawing paper, A5 size in a spiral bound notebook. For me this is the right size for portability and ease of holding at the telescope. This sort of drawing paper can be found at all good newsagents or stationary stores.

At the head of each page I write in headings for the date, time, observing condition (cloudiness, sky quality, wind conditions), and then I draw in observing blanks. These are simple circles where I will draw the image. This is a highly technical production; I use a 2B pencil and the eyepiece dust cap of my telescope to draw a number of circles. I find this just about the right size for reproducing what I see in the scope. More technically minded people can use a popular word processing program to make the blanks, but you really need a laser printer for printing the blanks. Inkjet print will smear when you handle it while sketching, and any trace of dew will wreak havoc. Also, if you are printing out pages, you will need a clipboard or solid surface to support your sheet while sketching.

Having set up your sketching blanks, its worthwhile making sure you have two sharpened 2B pencils with you (or coloured pencils). If a pencil point breaks during sketching you don’t have to hunt around for a sharpener then.

Now you are at the telescope, how are you going to actually sketch? After all, it is dark! I usually do my planetary observing in suburban locations where there is enough stray light to see the page (but not enough to degrade the planetary image), but if you are observing in dark sky sites, I find a hands-free LED headtorch, with red cellophane wrapped around it so your (and other peoples) night vision will not be affected, is ideal. It also helps with all the telescope set up that you do as well. LED head torches can be found relatively cheaply at bushwalking or sports stores, and red cellophane can be found at any newsagent. David Reidy and Ken Wallace recommend one of those booklights that you can clip to a book or clipboard. Experiment a little to find the best and most comfortable method for yourself.

Now, you are at the eyepiece, pencil in hand poised above your planet blank, how do you actually start? I take a good look at the planet, memorize what I have seen, then glance down at the blank and quickly sketch in the major detail. As I wear half glasses for reading, I can wear the glasses at the telescope, look through the lens sans glasses, then look through the glasses at the sketch pad. I then look back through the scope, then back to the pad and sketch in more detail. I repeat this until I have built up a detailed sketch of the planet. You may find that the first time you look through the eyepiece, there is little detail, but don’t worry, just sketch out the main features and you will find that as your eye becomes adapted, you will be able to see more detail. Unguided scopes can be a bit of a pain, as you have to bring objects back into the eyepiece fairly often, but I spent most of my sketching career with unguided scopes, and you can still get good sketches. Made a mistake? Don’t panic, just start again, or use an eraser, to clear out the mistake.

It’s worthwhile practicing a bit before trying your hand at planets. The Moon of course is ideal for practise, bright, full of detail, and you can start sketching in the early evening (planets like Jupiter, Saturn and Mars are best when highest in the sky, which is often inconveniently late). Once you have had a go at the Moon, planets should be a doddle. Try experimenting with coloured pencils,. Jupiter, and Mars at opposition, is particularly good for colour. Getting the shade right may be a problem (especially under redlight conditions). Again, don’t be afraid to experiment.

Again, you are not limited to the telescope. I have sketched through binoculars (good for asteroids and moderately bright comets, see the sketch of comet V1 NEAT sketch through binoculars to the left. I made multiple sketches over several days showing the motion of this comet), and with the unaided eye (bright comets, planetary motion etc.), you are limited only by your imagination, a comfy chair and a good supply of sharp pencils. So pick up those pencils and get sketching!

Labels: comets, Observational Astronomy, sketch