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Astrophotography and Sketching >> Sketching

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idp
sage


Reged: 08/21/09

Loc: New Haven, CT
Re: Saturn April 4 new [Re: David Gray]
      #5785663 - 04/08/13 11:03 AM

Quote:


Encke div: I spout off about this IAU thing at any opportunity it’s had me riled for years! I got the impression those that might have had some influence just seemed to roll over and accept it – speaking to, among others, upper-level BAA people back then.




I see. That surprises me a bit, as IAU nomenclature is first of all historically inaccurate and I'm sure BAA guys knew well about that...

Quote:

though for myself I like your term "draftsmanship"!




Uhm...not a native English speaker, so "draftsmanship" might not be accurate Or maybe it is American (I live in the USA now), or related to technical drawing rather than artistic, or I may just have invented it

Anyway, your drawings of Saturn are by far the best I see around; would love to know more about your technique. It takes both an experienced observer of the planet and a good artist.

Ivano

Edited by idp (04/08/13 11:05 AM)


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: idp]
      #5786160 - 04/08/13 02:33 PM Attachment (18 downloads)

Quote:

[around; would love to know more about your technique.




Draftsmanship: well I am far-north English born (mainly Celtic/Viking stock here!) so draughtsmanship; but that or artistic I guess I traverse their hazy boundaries. I have been accused of trying to produce planetary works of art; but I say if you get what you see at the eyepiece accurately, then, as they are often objects of beauty, the art takes care of itself! I have to say that assorted candy-colours on planets etc. elude me: even so I find our ‘drab grey’ moon a rich palette of subtle hues!

My technique: a good HB pencil and stumps (medium & thin). I adopted a method of stump painting some years back and ‘tickle’ in darker features with the HB. To me, why draw with the pencil first then have to blend in the marks afterward. Stump first and much of the blending is done and at the eyepiece; saving time and more retaining the integrity of the drawing with it pretty much finished on site. I am attaching more details, but the reference to Staedtler Mars Lumograph EB pencils is out of date as I find they (& EE) are discontinued now. Replaced with, I think, 8B & 9B graphite. A great shame as the EB takes a fine point and is ideal for Cassini div. C ring, and shadows etc as it has considerably less sheen than graphite – glad I bought a good stock years ago!

Erasers: I do not anymore use kneaded (putty) erasers as with using the stumping technique any putty-residue on the paper will greedily grab the graphite from the stump and leave a virtually irremovable dark patch. I find a good triangular pencil-end rubber perfectly fine and convenient.

Paper: I used to use Ivorex or Bristol Board. But now use Xerox Colotech+ (100 gsm) inkjet printer paper £10 ($15) for 500 sheets some years back; and some years back got a deal on three packs for £20 ($30) and have just recently started on the second. So much more economical than the board; very smooth, white (no yellowing yet!) and damp-resistant outdoors at night. Also gives good prints!

For planets with very delicate diffuse features I prepare the drawing area by rubbing all over in small tight circles with a small wad of tissue or cotton wool. This dulls the tooth making very smooth blends possible. With Saturn I apply this more thoroughly to the rings than globe area. I use small tight circles when stumping also, unless I want to lightly reinforce a faint belt, ring div or such.

David.


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idp
sage


Reged: 08/21/09

Loc: New Haven, CT
Re: Saturn April 4 new [Re: David Gray]
      #5786243 - 04/08/13 03:40 PM

Awesome tips, thanks!

Ivano


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Saturn April 4 new [Re: idp]
      #5787196 - 04/09/13 12:20 AM

So these oculars deliberately showing chromatic aberration work to cancel out atmospheric dispersion colors on things particularly like Galilean moons at high power and such? Amazing .

Could you explain it a little further? Is this a standard tool or method or one you developed on your own. Its the first Im hearing of it . Particularly in Connecticut in winter, dispersion can be very degrading to the image indeed. It'd be a fine thing if I had such a thing to counter its effects.

Pete


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: azure1961p]
      #5787303 - 04/09/13 02:48 AM

Quote:

So these oculars deliberately showing chromatic aberration work to cancel out atmospheric dispersion colors on things particularly like Galilean moons at high power and such? Amazing .

Could you explain it a little further? Is this a standard tool or method or one you developed on your own. Its the first Im hearing of it . Particularly in Connecticut in winter, dispersion can be very degrading to the image indeed. It'd be a fine thing if I had such a thing to counter its effects.

Pete




If you have “The Planet Jupiter” (1958) by B.M. Peek then you can find my first source of information in chap. 5 (OBSERVATIONS OF COLOUR) page 38. Also Sidgwick’s classics deal pretty thoroughly with chromatic aberration in general and may touch on the Ramsden effect. If you can’t access these I will be glad to quote some passages.

Actually a narrow angle dispersion prism, as used by many imagers now, would be the ideal; but needing differing angles for varying altitudes. There are variable ones available – one I have seen retails at over £300 ($450): I am just a poor pensioner! S&T years ago gave details of H.E Dall’s Compensating Eyepiece where the crown and flint components of the field lens are uncemented and a thumbscrew (with a graduated scale) alters the position of the flint against the crown.

In principle I would not be inclined to tackle the Galileans for detail at other than a goodly altitude where the atmospheric effects would be minimal. But it would certainly bring out truer colours (ball-park!) lower down.

Whilst checking out Peek I re-read (after many years) the “Drawings of Jupiter” section - page 35 bottom half to 36 where he had described an observing technique that years later in S&T Alika K. Herring (a bio.) wrote that a seasoned U.S. observer had told him in his early years: that we should look on a planet rather than at it. Those who seek elusive detail should particularly note this apparent absurdity – my experience finds it quite logical!! Hope you can see Peek’s book: and I will have to dig out those S&Ts to check the details against my memory!

Edited by David Gray (04/09/13 03:03 AM)


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kenrenard
Carpal Tunnel


Reged: 12/13/12

Loc: Dunmore, PA
Re: Saturn April 4 new [Re: David Gray]
      #5787488 - 04/09/13 07:07 AM

David,
This has been a fascinating post. As a beginning sketcher and novice observer your detailed information is wonderful. I look forward to see more of your posts and drawings.


Ken

Edited by kenrenard (04/09/13 07:10 AM)


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: kenrenard]
      #5787523 - 04/09/13 07:45 AM

Much appreciated Ken - thanks.

David.


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Paul G. Abel
sage


Reged: 01/28/10

Loc: UK
Re: Saturn April 4 new [Re: David Gray]
      #5787550 - 04/09/13 08:13 AM

An absolutely splendid rendering David, I really am most envious of your talents. Oh if only I could produce drawings as realistic as this!!!!!

Looking forward to seeing more of your work later in the apparition!

Best wishes,
-Paul


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idp
sage


Reged: 08/21/09

Loc: New Haven, CT
Re: Saturn April 4 new [Re: David Gray]
      #5788650 - 04/09/13 04:34 PM

Quote:

I have been accused of trying to produce planetary works of art; but I say if you get what you see at the eyepiece accurately, then, as they are often objects of beauty, the art takes care of itself!




This is an interesting point you bring up. The Italian astronomical union also emphasized, in its training program, the accurate measurement of intensity and positions over the realistic rendering of the planet. Back then, visual observations were after all the backbone of observing programs and the most important source of information on the planet.

However, it was never implied that artistic representations and accuracy would conflict, and personally I don't see why they should; they certainly didn't historically. The idea was that while few have the hand of an accomplished draughtsman (hey, the spell-checker is taking issue!), almost everyone can be trained to carry out useful and reliable observations.

I hope you will keep using your rare talent, and sharing it with us.

Ivano

Edited by idp (04/09/13 04:35 PM)


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Uwe Pilz
scholastic sledgehammer


Reged: 05/16/08

Loc: Leipzig, Germany
Re: Saturn April 4 new [Re: David Gray]
      #5789407 - 04/10/13 12:13 AM

Dear David,

these are real great sketches of Saturn. A have such a steadiness of the atmosphere not more than one time a year at my observation site. Thank you for sharing.


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: Uwe Pilz]
      #5789690 - 04/10/13 07:27 AM

Much appreciated Uwe and Paul.

I do seem to enjoy much good seeing here: my best seeing 'seasons' seem to be April/May & Sept/Oct; but getting relatively good spells year round contrary to the UK's reputation with this. Perhaps I am favoured with a somewhat unique/anomalous micro-climate.

The lie of the land may have something to do with it as we are considerably, quite abruptly, higher here than to the s'east south & s'west. I have found those good conditions here since arriving to take up home in 1976. It certainly seems more consistently good than when I observed (1961-76)from Trimdon some 8 miles n'east of here - but there were more houses surrounding there: being pretty rural here.


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: idp]
      #5789754 - 04/10/13 08:17 AM

Quote:

Quote:

I have been accused of trying to produce planetary works of art; but I say if you get what you see at the eyepiece accurately, then, as they are often objects of beauty, the art takes care of itself!




the accurate measurement of intensity and positions over the realistic rendering of the planet.




Yes very much agree; and when they (accusers) say “art” I think they have in mind the more embellished types – what John Rogers (BAA Jupiter) calls “fairy castles”!

Making intensity estimates (done thousands) is a good part of training for a more accurate drawing tonally. Being a baker for 50years (the craft-bakery kind as opposed to the supermarket type!) may well have contributed to my sketching efforts. Intensities (10 = black): I did considerable amounts of oven-work where intensities are a large part: too much darker than ints. 6-7 and you would be sent elsewhere!

John Rogers once told me that my personal equation for central meridian transits was uncannily near to zero – I responded “you have to be able to spot the centre of the cake to get the cherry there”!

Previous post I mentioned my artist mother and her elder sister Florence. I would say both could produce accurate renditions; but I would say to mother that her paintings were more impressionist than my preferred detailed ones by Aunt Florrie. She would reply “Oh I can’t do them like her”!

David


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: David Gray]
      #5789777 - 04/10/13 08:39 AM Attachment (11 downloads)

With further regard to using a Ramsden to cancel atmospheric dispersion attached is something relating to this that I was working on back in 2009 but never followed up – as with many things!

Actually being a humble Ramsden it was never ideal for the finest detail; so was happy to discover (my prev. attachment) that the prisms in the optical train put enough chromatic inequality back to still apply the Ramsden technique and with much superior eyepieces.

I have come across a CN post (“CPC 11 screwing up Jupiter?”) that dealt with this issue and I see that brianb11213 got it sorted!

http://www.cloudynights.com/ubbthreads/showflat.php?Cat=&Board=nexstargps...

It must be said that as the 415mm D-K works at f/16 (6640mm f.l.) it handles simpler eyepieces very well. But I prefer wider field types such as the Plossls referred to in the earlier post/attachment.

Edited by David Gray (04/10/13 09:03 AM)


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kenrenard
Carpal Tunnel


Reged: 12/13/12

Loc: Dunmore, PA
Re: Saturn April 4 new [Re: David Gray]
      #5789917 - 04/10/13 10:13 AM

David,
Pardon my ignorant understanding of eyepieces, but being a skilled planetary observer as yourself. Can you make a recommendation for a good eyepiece say in the 10-12mm range with decent eye relief. I often see many post speaking of very expensive eyepieces which no doubt may be good but am wondering how much a novice observer with a 8 inch 1200FL F5.9 reflector will see such as myself. I enjoy viewing planets from my home and just started sketching deep sky objects and would like to try the Moon and planets at some point. I would like to get your thoughts on what you think is important and what is just sales hype.

Also do you have a website or a place where some of your articles are? I would certainly enjoy to read more. You have a very interesting telescope as well.

Thanks

Ken


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: kenrenard]
      #5790170 - 04/10/13 12:11 PM

Thanks Ken: I’m not well abreast of what is on offer these days but the Meade 5000 Plossls mentioned/shown in my recent attachment I have found to be perfectly suitable for my purposes. With your scope at f/5.9 this type should be well suited for planetary work with one proviso: seek out a good quality Barlow a variable one if possible then you do not have to use what I call peephole high power types. For example a tiny 4mm would give x300 – if your scope/conditions can handle it! So if you seek powers twixt 150-300 your proposed 10-12mm with a x2 Barlow would give 240-200. I have used a friend’s 8” Celestron at these powers and had very good views of planets. Also the 415mm D-K with a 6” off-axis stop at up to x365 (c.f/44!). When my 10" f/8 Newtonian was in use I used x250 (8mm Orthoscopic) very successfully.

I can’t tell you the pleasure and comfort it is to be using larger eyepieces at high powers without risking compromising (and with more eye-straining) fine detail and delicate contrast detection with those awkward 4mm and even 6mm ones. From what you observe now (DSO) I guess you will already have some of the larger long-focus types: if they are of good design and quality then all you may need is a good quality Barlow of appropriate amplification?!

I do not have a website or such, but have considered it - we'll see! My 415mm Dall-Kirkham was made to my specification back in the mid-70s by James Muirden (optics) and Peter Drew, now at the Astronomy Centre Todmorden UK, did the mechanical components. The mirrors were last re-coated in 1989 by (in person) non other than, the now late, David Sinden (formerly of Grubb Parsons) who also worked with such as the 98” Isaac Newton and larger (AAT etc). Testimony to his work that in recent years I can still see stars accurately determined fainter than mag. 16 (tho’ 15 with the binoviewer attached).

David.


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kenrenard
Carpal Tunnel


Reged: 12/13/12

Loc: Dunmore, PA
Re: Saturn April 4 new [Re: David Gray]
      #5790257 - 04/10/13 12:48 PM

Thank You David,
I really appreciate it. I have a 24mm Panoptic eyepiece which I am very fond of. It is very clear edge to edge. I bough a TMB 5mm eyepiece and do like it but found it to work only a few nights a year with seeing here in the Northeast US. I will look into a good barlow as you have suggested.

I certainly have enjoyed reading your posts as well as learning more about your telescope. It must be an impressive scope to look through. Thanks for taking time out of your day to answer my questions. I really appreciate your response.

I look forward to seeing your other drawings and posts.

Clear Skies

Ken


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chrisrnuttall
Professor Emeritus


Reged: 12/29/10

Loc: York, England
Re: Saturn April 4 new [Re: kenrenard]
      #5793802 - 04/12/13 04:49 AM

David
What a beautiful drawing of Saturn, the colours are many and varied, but also subtle and realistic (no candy colours here). I'm not sure how anyone can say that such a rendition could be astronomy-art, rather, it is simply a faithful reproduction of a beautiful planet, and this is the goal of everyone who contributes to this forum. It's the reason we draw the objects we see through our telescopes; they are beautiful, awe-inspiring things, which we try to reproduce on paper or screen as perfectly as we can, and in doing this we can capture the changing details on these objects which collectively form a useful scientific record which grows over time.
I too love the personal connection I feel with the object I am drawing and whilst imagers are able to record finer details with less uncertainty, I think that it is a colder and less enjoyable pursuit, obviously others disagree, and that is what makes it all so interesting.

David, it is fascinating to read your posts here, your drawings have amazed me for several years but I had no idea that you held so much knowledge about the process/art/science of visual observing, I am glad you seem keen to share it. Like Pete I am intrigued by the idea of cancelling atmospheric colour smearing with the introduction or contrary chromatic aboration in the optical train. I wonder if the prism in my binoviewer will be doing this to some degree?

Re: Kenrenard, I have found that Televue plossls, University Optics orthoscopics, and Baader Genuine orthoscopics give fine views of the planets. There is much to read on the web about eyepieces for planets, but in general go for simplicity of design and highest available quality. Don't spend hundreds on wide-field eyepieces for planets, they are a waste of money.
I also use a binoviewer with a glass-path corrector which amplifies the power of the eyepieces, meaning I can use longer focal length eyepieces at high power, it is very easy on the eye to do that.


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: chrisrnuttall]
      #5793957 - 04/12/13 08:35 AM

Quote:

I too love the personal connection I feel with the object I am drawing and whilst imagers are able to record finer details with less uncertainty, I think that it is a colder and less enjoyable pursuit, obviously others disagree, and that is what makes it all so interesting.




Many thanks Chris:

I had thought that in later life with perhaps failing sight that I would have by now resorted to imaging, As I am soon 69 yrs I had thought that by now my eyes would have deteriorated somewhat. Apart from becoming slightly longer-sighted some ten years back, which seems to have stalled in recent years, I find no loss whatsoever. I often joke I can read the time on a church clock etc. a mile away with more ease than the watch on my wrist!

Imagers are producing wonderfully detailed work now and far more scientifically useful than I ever could and hopefully never pretended to! However in recent times when getting those rarer exquisite views I have come realise that I could never go to imaging. I am not a religious person but when experiencing such sightings there is something there that neither myself nor the imager (even Hubble!) manages to capture and defies recording – but as you say “personal connection”. The legend I understand is that trying to capture this contributed to Van Gogh’s madness…??! So it is that I would never go over to imaging: if not contradictory - stunningly detailed as they are; for me they become the poet’s “Cold-star bane that deadens human hearts” - Blake? Milton? Educate me someone!

When the acuity fades I may well go more into the speculative astro-art al la Bonestell, Hardy et al. Of course applying, as they, scientific discovery/principles for accuracy!!

I agree with what you say to Ken about eyepieces. My choice of the 20mm Meade 5000 Plossls with their 65 deg. field proved ideal for planets as there is barely noticeable distortion right across the field – even at the edge! The relatively wider flat field is good in another regard: my D-K has had no working drive for many years (you adapt) something I had hoped to rectify when I retired: but so many diversions! Also fairly inexpensive as oculars go – a big consideration when you have to buy in pairs for binoviewers!

Again my thanks for your compliments – your work has my high regard also.

David.


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kenrenard
Carpal Tunnel


Reged: 12/13/12

Loc: Dunmore, PA
Re: Saturn April 4 new [Re: chrisrnuttall]
      #5793974 - 04/12/13 08:52 AM

Chris,
Thank You for your assistance with eyepieces. I often see so many new folks just buying equipment for the sake of having the latest gadget. When I see sketches like yours and David's I see a keen observer. I trust your and David's opinion on eyepieces by looking at your skilled drawings. I just started sketching and I only have a few years observing under my belt. I have learned so much in the sketching forums and I am glad I started sketching and reading the posts here. I will look into a binoviewer down the road. Unfortunately sitting at a computer all day my eyes are not the best. So eye relief will help. I will look into the eyepieces you suggested. I think a 10 -12 mm may be my sweet spot with seeing where I live.

Thank You again. Your drawings are very beautiful.

Ken


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chrisrnuttall
Professor Emeritus


Reged: 12/29/10

Loc: York, England
Re: Saturn April 4 new [Re: kenrenard]
      #5794754 - 04/12/13 03:33 PM

David / Ken, I work mostly at a computer these days and I have developed a dioptre of astigmatism in both eyes over the last five years; my eye sight was always razor sharp until then and it lead me to believe I had defective eyepieces, binoculars, even an entire telescope, not to mention the TV! Eventually the unthinkable entered my head and I got an eye test. I now have glasses for screen work. Luckily for us astronomers it seems that a bit of astigmatism doesn't matter with smaller exit pupil images through telescopes, and apparently myopia can be corrected with the telescope too.
I can see the attraction of imaging; I captured dozens of driven digital camera photos of Comet Panstarrs the other week and I quite enjoyed it, but I think my first love will always be to spy with my own eyes at those secret things in the sky, and then to draw them.

Once the clouds go away I really must turn my 12" to Saturn for the first time, I have always done fairly well with its belts, but detail on the disk has never come easily 'til now, (the dragon storm in my Avatar excepted!)the biggest scope I have used on Saturn so far was my 8", which whilst being an excellent scope was just not big enough!

I hope to be able to see the kind of detail in the sketch at the top of the page, that will be very exciting!


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