Lulin, blazar, open cluster and Ha prom (really)
Posted 02 March 2009 - 06:46 PM
Posted 02 March 2009 - 10:01 PM
I really enjoy your solar sketch. Having recently observed NGC 2438 I enjoy your capture of his PN, especially the star on the eastern edge. I haven't viewed Mrk 421 yet I enjoy the contrast and the labeling you've done there. Lulin is wonderful sketch and I enjoy the tail, the coma and other parts. As always your background stars are tremendous.
Posted 03 March 2009 - 12:36 AM
Great collection of sketches. You always do a first class job at the eyepiece.
I caught MK 421 at about 12 mag. back in 1982 when I was monitoring it for variability.
Posted 03 March 2009 - 03:24 AM
An excellent set of images of solar prominences, M46 (containing the planetary nebula NGC 2438), Markarian 421 (a Blazar, or a cross between a quasar and a galaxy), and Comet Lulin. They all show impressive detail. Thank you for sharing them with us all.
Posted 03 March 2009 - 05:08 AM
The glare around the two bright stars in the Mrk421 sketch represents a new technique for me. (It was added digitally while I was adding the crosshairs and mag numbers.)
Anyway, I think I like it better than an earlier effort on Abell 12 (using faint pencil spikes), but I'd be interested in your opinions:
Posted 03 March 2009 - 07:27 AM
A great diversity of multiple sketched images! Seeing your h-alpha image of the sun and Erika's nice sketch in the current monthly contest has inspired me to observe the sun again soon when the weather permits.
Your other deep sky works are a great inspiration for me to venture out more as I have never observed Abell 12 yet. I had to search it in the web to inform myself and this came up first. A photo, a sketch and requirements to use OIII filter and suburban skies to see (Is that true?)>
Thanks for posting as I always learn something new from your sketches,
Posted 03 March 2009 - 09:08 AM
My observing notes:
Abell12 1/30/2008 00:15UT; Pickering 9, NELM 6, SQM 20.8
Unfiltered at 260x the PN is lost in the star's glare. However, if you move the star around the in a circle just outside the field-stop, an egg-shaped section of the glare remains when the star is off the ESE edge.
PN easy in averted, and sometimes direct vision with aggressive filtration (OIII). No structure in PN, but it does have somewhat of an egg shape.
Note that the evening was pretty dark and transparent for me (NELM 6 as opposed to my more usual 5.5). Under more light polluted skies, or with smaller apertures, a UHC or OIII filter might be required.
Posted 03 March 2009 - 09:16 PM
An excellent observation of this interesting planetary nebula in Orion. Thank you for sharing it with us all.
Posted 03 March 2009 - 10:28 PM
Thanks to all of you who post here for dedicating your time and observing skills for us to enjoy the art of the science.
Regards, Jason H.
Posted 03 March 2009 - 11:11 PM
I haven't tried toying with the digital aspect yet, I'm still trying to improve my skills with charcoal/pencils.
Posted 04 March 2009 - 04:47 AM
Any other opinions on shaded digital halos (a la Mrk421) vs. spiky pencil ones (a la Abell12)?
Posted 04 March 2009 - 09:30 AM
As for the digital halos vs. spiky ones, I'd go with whichever is truer to what you see visually. Personally, the digital one matches better to how I see halos visually, so I'm partial to that one.
Posted 04 March 2009 - 10:51 AM
Very insightful question. I think the answer is both: I see the spiky version at a much smaller scale, surrounded by the halo.
Which brings me to a third attempt:
Posted 04 March 2009 - 12:02 PM
Posted 04 March 2009 - 12:12 PM
Posted 04 March 2009 - 12:31 PM
Yeah, neither am I. I was trying for a softer touch, but I did it digitally where I'm all thumbs and big toes (or something like that).
Posted 04 March 2009 - 12:38 PM
"Use the blur filter, Obi-wan!"
(I also shrunk them down slightly, and bumped up the brighness at the very center.)
Posted 04 March 2009 - 01:08 PM
As a quicky, rough example, here's sort of what I meant. I'm not very good at this at all.
I think you are better than you realize. You have rendered a very realistic star image with halo.
I believe we can all learn Photoshop techniques with some practice but for me, getting the chalk on my hands and using old classic techniques seem to make for a greater challenge.
I have used Photoshop but only to save and store the art. I tried to add sometimes with Photoshop enhancement as Jeff did here but later chose to stay in the old medium of art as some people still ask me if my sketches are all hand sketched only. As you mentioned earlier in another post, you said that you used to clean up your chalk smears in Photoshop but then you said that you stopped doing that. Can you elaborate on that and tell us why? I think there is something about an artists work showing what some might consider as little errors. That is what did it for me when I saw your solar prominence sketch on Oct 12th 2006 in Spaceweather.com [If I haven't told this enough ] That is why I started seriously sketching and why I am here in CN today.
Thanks for any further info. I commend you and Jeff for starting a great tutorial here for new sketches to consider old classic rendering vs Photoshop and/or combinations of mediums.
Posted 04 March 2009 - 03:42 PM
Like Frank said : a first class job!
About the brighter stars, I tend to follow Erica's advice : a subtle mix of halo and spikes.
Posted 04 March 2009 - 04:55 PM
You need to ask "yourself" some questions at some point- which way "do I think is best"? Am I trying to make a pleasing sketch for myself or others? Am I trying to make a realistic sketch as I see it? Am I trying to do all of these at the same time? If the seeing is very good you may see diffraction rings in addition to spider diffraction spikes. Should I put all this in a sketch? If the seeing is bad the stars may be blurred. Should you sketch the stars blurred if they look that way? Should you sketch them the way they look under ideal conditions if conditions are not ideal?
These are the kinds of questions you are asking yourself now. Jeff, your sketches are fantastic and continue to get better. Certainly better than anything I have done.
I don't feel there is any one best way.
I have yet to make a sketch I am completely happy with. It may never happen. But the quest is the fun part anyway.
The variations in sketches submitted here makes this a wonderful place to visit, look and learn.
For me there is no one best way to sketch anything astronomical. All sketches are the mind-eye-hand of our fellow beings. Vive la difference!
Posted 04 March 2009 - 11:57 PM
I see the spiky version at a much smaller scale, surrounded by the halo.
Jeff, do you think the spikes are seeing "warbles" (see the lower end of the Pickering scale) or just the fact that you're observing bright stars that show up "spiky" to you through the EP?
I haven't tried to capture that level of detail in my stars, but if I get a great night of seeing I'm definitely going to sketch the airy disc. I don't often get to see it except if I push the magnification really high.
Posted 05 March 2009 - 04:57 AM
He, he, the answers to those questions are messy, at least for me.
I started sketching as a way to share an accurate representation of what one might expect to see through various instruments (something that astrophotos can't do very well). And I'd still consider myself a fully-paid-up, card-carrying member of the realism school. If I see glare, I render it. If my scope had a spider, I'd render the diffraction spikes. But....
Last night I was sketching Lulin (next to a beautiful carbon star), and I found myself re-positioning my binoculars to render the stars in the outer 15% of the field. Take note of what that means -- I did not render the astigmatism that they showed while near the edge of field.
As I've gotten to be a more skilled observer, I also find myself rendering features I deduce, but don't really "see". For instance, if a galaxy shows a small elongation E-W in direct vision, and a larger elongation N-S in averted, then I can be pretty sure there's a galactic bar E-W and an extended disk N-S. But is rendering the bar really what I "see"? I don't have a ready answer to that.
Solar has also "led me astray". In H-alpha, due to the color and immense amount of detail on the disk, photographs show a more accurate representation of what one might see than sketches. But I still sketch prominences because I enjoy it, and others enjoy my work. (Which sounds a lot more like "art" than "realism".) But I am still true to my roots, and I attempt to sketch what I see as accurately as possible.
Now you've got me wanting to experiment again. I'm going to go back and render some astigmatic stars in that Lulin sketch and see how it looks....
Posted 05 March 2009 - 05:07 AM
I believe it's the seeing, but it could also be my eyes. Most of my sketches are done through the 16", which presents tiny, tiny Airy disks (much to small for me to see at anything under 1000X). But it could certainly be the seeing-induced warbles in the whole Airy pattern.
The effect is highly accentuated with bright stars (Sirius, in particular), which one would expect with seeing-induced effects -- but might also be a factor with eye-induced aberrations.
FWIW, I judge the seeing through my 4" refractor using 320X. The Airy pattern is reasonably easy to see at that scale, with the disk and portions of perhaps the first 3 rings on a steady night.
Posted 05 March 2009 - 06:16 AM