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Sidewinder
31-12-2006, 07:57 AM
Hello fellow astronomers!
I hope you had a great holiday, down there in summery Australia!
Over the last weeks, I have gone quite amiss, there was a lot of work to do and the sky was overcast most of the time anyways. But just before Christmas, the weather showed its best side and the skies cleared up, providing very good observing conditions around 6m0, from one of my observing sites in Bavaria, located at a height of about 800 meters.
I decided to do some sketching with my Vixen 4.5" Newtonian on a Vixen GP equatorial mount - just to prove, what a small opening can provide for deep sky observing.
The five sketches I want to present today are only a part of what I had really drawn, still, it is a lot of work to re-process the sketches digitally, thus I haven't gotten around to re-work them all. So stay tuned to some more drawings in the future.

Sketch Number One "µ Cephei": This is a drawing I had already done back in November, the only drawing of that awful month. It's µ Cephei, a variable star in the constellation of Cepheus and reportedly one of the "reddest" stars that can be observed with the naked eye. A telescope intensifies the apparent colour. It's a Red Giant with a period of approximately 730 days.

Sketch Number Two "Messier 1": This is a well-known object, the Crab Nebula in the constellation of Taurus, one of the favourite winter objects here in Middle Europe. Being very sensitive to light pollution, a little flame is clearly visible under good conditions, even though no apparent detail can be observed, even with bigger apertures. The object is the remains of a supernova, which occurred there in 1054, thus making it one of the youngest objects visible with the telescope. For me personally filters provide not much use, because it is mostly synchrotron radiation, which is emitted by the nebula.

Sketch Number Three "NGC 2392": Fitting for the holiday season, an Eskimo makes its way across Europe's frosty nightskies. It's a planetary nebula, which offers the view of an Eskimo head on photographic long-time exposures. This cannot be seen with the 4.5" Newtonian, however, a triple division is clearly visible: there is a very bright, almost stellar central core, surrounded by two halos, one brighter and one fainter. A very nice sketching object, even for small apertures.

Sketch Number Four "M 78": M 78 is an easy to find reflection nebula in the constellation of Orion. Clearly visible in the 4.5" Newtonian are two "central stars" and a diffuse nebula, which spreads out into south-east direction. This is giving the nebula an almost cometary appearance, making it an interesting object for observation. Even though it is very bright, still a lot of averted vision and concentration had to be applied, to work out at least some details.

Sketch Number Five "NGC2903": This is a pretty bright galaxy in the constellation of Leo, clearly visible in a small telescope. The galaxy itself does not reveal a lot of detail, there is a relatively bright, but not stellar core, which is surrounded by a diffuse milky halo, spreading out from north-east to south-west direction. The galaxy is surrounded by a few stars, which can be helpful for focusing. Another galaxy for small apertures, which can easily make a stand against many Messier objects.

I hope you enjoyed viewing the drawings and read the little notes. Even though I own and have access to bigger-sized telescopes, I always like to bring out the 4.5" every once in a while. The biggest advantage of this little telescope is that it is pretty light, thus pretty mobile and easily set up on it's equatorial mount. When I bought it, I was lucky and got one with excellent optics - in the hands of the concentrated and motivated observer, it can be a real deep sky weapon.
I just want to encourage people with small apertures to go beyond the moon and planets and try to push a little further into space - actually, NGC 2903 is about 25 million light years away, still an easy catch for the 4.5".

Have a happy new year!

Sebastian

Orion
31-12-2006, 08:05 AM
You did a fantastic job at sketching Sebastian, the patience it must require.
Wonderful work.

sheeny
31-12-2006, 08:21 AM
Great work there Sabastian!



What do you do to re-process them digitally? Do you scan and invert/process them or are you redrawing them?

Thanks,

Al.

h0ughy
31-12-2006, 09:31 AM
fantastic, AstroSouth would love those too. They are great

Sidewinder
31-12-2006, 09:35 AM
Hello Ed and Al!
Thanks a lot for your kind words!
I am glad, if people like the sketches!
As for the re-processing: first thing I do is scanning the sketches, then I do an automatic correction of contrast, brightness etc.
The next step is inverting the sketch and adjusting the brightness to exactly that degree, where not much information on the objects is lost, but where scanning artifacts are no longer visible, this can be a bit tricky. Then I start polishing up the sketches, this means erasing mistakes, pencil streaks, all that stuff that simply happens, while sketching on the telescope. The next step is re-processing the stars, this means that I assign a certain brush size in Adobe Photoshop to the relative brightness of a star, then I erase the hand-drawn star until there is just one pixel left marking the exact position, the brush is then centered just above that pixel with exactly the right size and one click on the mouse produces a nice and round star, which still looks natural, not computer generated.
In the next stage colour and glow can be added to the stars, this is done in a combination of tools, mainly various brush functions and the gaussian blur, it can be tricky and there is no general order in which to apply the various functions, even though I've come up with a certain routine.
If the object is a star, double star or open cluster, the process is now almost finished. If the main object is a galaxy or nebula, this object must also be reworked, though not as "radical" as the stars, it is mainly left, how it was drawn, some blur can be added, a bit of tidying up can be done, errors removed etc.
The final step is lighting the brightness of the background (+11 in the brightness adjustment tool in Photoshop), to enhance the detail and make it all look more natural.
Last but not least the drawing can be presented in the internet (and torn to bits by far superior sketchers ;)).
My aim is to use the benefits of digital processing without losing the natural look of a hand-drawn picture, I am not sure, how successful I am.

To illustrate the steps described above, I attached another drawing of the phantastic Plejads, one of the mighty winter objects here. It's completely fresh out of the press, finished in these minutes. The drawing was processed in exactly the described way above. Without the help of digital reprocessing, I could never have added the bluish glow, we all know, from observing this wonderful cluster. Still, I think it looks quite natural. :)
Merope Nebula was not visible, unfortunately.

OK, I hope, I wasn't going into detail too much, perhaps it becomes apparent, how much work goes into those sketches, even though they are no match for the might photographs presented here. As for the Plejads, I took me about 20 minutes to draw them on the telescope and about 45 minutes to re-process them, this adds up to more than an hour of work!
If there is any interest, I could write a tutorial to pass on my limited knowledge, but if you want to see real astronomical art, look for Jeremy Perez on the net, the guy is fantastic, many ideas, I use for re-processing, have in one way or the other originated from his mind, I just took them and worked around on my own, but I owe him a lot!

Sebastian

Sidewinder
31-12-2006, 09:36 AM
Thanks a lot to you, too, Houghy! :)
You answered, just as I was writing!

astro_south
05-01-2007, 01:42 PM
You are certainly right Houghy

Great work Sebastian!! I would be interested in your tutorial too - you seem to involve more post processing once you have scanned than I have ever thought about - maybe it is something I should look into.

I will be searching for Jeremy's work too :thumbsup:

Ric
05-01-2007, 04:43 PM
Hi Sebastian, what a fantastic set of images you have sketched, great work and very inspiring.

I enjoyed looking through them very much.

Cheers

Sidewinder
06-01-2007, 02:06 AM
Hello Andrew, Hello Ric,
thank you very much for your kind words, too!
It's always great to get some feedback and to hear that people like, what you are doing.
The next time, I'll make a drawing, I'll post a step by step tutorial of how I process it, maybe it's of use for one or the other. Still a lot of stuff, I use, has been done by people before and I just copied it in one way or the other, even though I might do some things differently.

To make my set of Christmas Drawings complete, I'll post another two sketches, one of M44 and one of NGC 457.

M44, Praesepe or The Beehive, as it is called, is one of the greatest open clusters of the whole sky, maybe even greater than the Pleiades. It's located in cancer and about 570 light years away, it is suggested that the stars originated from the same intergalactic nebula as the Hyades, which are close by, in Taurus. To me most of the brighter stars glow in blue or white colour, even though other colours have been reported. I tried to work that impression into my drawing.
NGC 457 is an open cluster located in Cassiopeia, and thus maybe pretty unknown in the Southern hemisphere. It is also called Owl Cluster, because the brighter stars, which shine in a yellow-orange tone, form the eyes, whereas the other stars seem to make up a body, spread wings and claws. The similarity to an owl is striking!
Funnier people also call it E.T. cluster, as seen from another perspective, it has some resemblance to the extraterrestrial.

Sebastian

P.S. Andrew, is there some website, where I can see your drawings?

Ric
06-01-2007, 10:21 AM
Hi Sebastian, very nice additions as well. The use of colour is a great touch.

Thanks for sharing