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Astrophotography and Sketching >> Sketching

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David Gray
sage
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Reged: 08/06/12

Loc: Co. Durham UK
Saturn April 4
      #5779122 - 04/05/13 08:37 AM Attachment (83 downloads)

Very nice view after some weeks of dismal cloudy nights (and days)!

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kenrenard
Carpal Tunnel


Reged: 12/13/12

Loc: Dunmore, PA
Re: Saturn April 4 new [Re: David Gray]
      #5779159 - 04/05/13 09:00 AM

David,
Stunning capture. I would love to see Saturn through your scope. Great Work.

Ken


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Jef De Wit
Carpal Tunnel


Reged: 03/06/09

Loc: Hove, Belgium
Re: Saturn April 4 new [Re: kenrenard]
      #5779176 - 04/05/13 09:07 AM

Looks like a photo to me

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Andrev
Post Laureate
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Reged: 02/08/11

Loc: Montreal, Quebec, Canada
Re: Saturn April 4 new [Re: Jef De Wit]
      #5779215 - 04/05/13 09:26 AM

Wow, what a beautiful sketch. So much details. Beautiful rendering.

Andre.


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dweller25
Pooh-Bah


Reged: 08/30/07

Loc: Lancashire, UK
Re: Saturn April 4 new [Re: Andrev]
      #5779271 - 04/05/13 10:07 AM

Excellent observation and sketch David, your 16" DK must be an impressive piece of kit.

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niteskystargazer
Carpal Tunnel
*****

Reged: 10/05/09

Loc: 41-43'-28" N 87-42'-39" W
Re: Saturn April 4 new [Re: David Gray]
      #5779328 - 04/05/13 10:33 AM

David,

Very good sketches of Saturn

CS,KLU,

,

Tom


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frank5817
Postmaster
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Reged: 06/13/06

Loc: Illinois
Re: Saturn April 4 new [Re: niteskystargazer]
      #5779788 - 04/05/13 02:44 PM

David,

That is a very, very beautiful sketch.
As Ken said, "Stunning".

Frank


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Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Saturn April 4 new [Re: frank5817]
      #5779807 - 04/05/13 02:52 PM

Yes, stunning is just shy of being the right word. Wow, beautiful.

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azure1961p
Postmaster
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Reged: 01/17/09

Loc: USA
Re: Saturn April 4 new [Re: Asbytec]
      #5780574 - 04/05/13 09:21 PM

The finish is nice but what I like most is the color fidelity.

Pete


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Asbytec
Guy in a furry hat
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Reged: 08/08/07

Loc: La Union, PI
Re: Saturn April 4 new [Re: azure1961p]
      #5780937 - 04/06/13 12:12 AM

David, what about Enke's division, ever seen it in your 16 incher?

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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: Asbytec]
      #5781171 - 04/06/13 05:58 AM Attachment (18 downloads)

Quote:

David, what about Enke's division, ever seen it in your 16 incher?




If you mean the Encke Minima (what I call the ‘classical Encke’): yes on very many occasions. If the IAU Encke then on average some five or so times per apparition (edge-ons excepted!), but only during better seeing. This latter to me is the true Keeler Gap: the IAU compounding the silliness by calling an impossibly fine line even nearer Ring A’s outer edge the Keeler. Can I see the IAU Encke as a ‘black’ gap like Cassini? Definitely not. On the BAA intensity scale (0 = White/Bright; 10 = Black) I usually make it twixt 7 & 8. Appropriately it looks to me quite like a fine lead-pencil line tho’ often a little diffuse – especially on the inner edge. I can’t rule out contrast effects entirely, but in my view perhaps 60/40: and undecided which predominates: real or illusion!! Nature seems to like hiding real features, at least to some eyes, under illusion/contrast effects; Saturn’s rings seemingly being particularly prone.

Somewhere in the BAA Saturn archive is a drawing of the only time I saw IAU Encke in my 10” (1970s?) also in their Journal – will need to check.

Attached is about the best view I ever had of Saturn. The original (HB pencil drawing) is a corrected scan. Never liked my scans as they usually necessitated a lot of computer work to bring them back with the original – very stressing (and eye-abusing!). Some would call this photo-shopping, but I largely contest this as the original is there for guidance; as opposed to giving some pimply model a flawless complexion (not denying some ‘primitive’ pleasure tho’!). In line with my current practice I plan to digitally photograph this, as correction is very minimal, and redo it with the saved colour hues – some cloudy night maybe.


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Kris.
Carpal Tunnel
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Reged: 09/16/04

Loc: Belgium
Re: Saturn April 4 new [Re: David Gray]
      #5781302 - 04/06/13 08:48 AM



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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Saturn April 4 new [Re: Kris.]
      #5781371 - 04/06/13 09:50 AM

I think photoshoping, or other image editing software is a necessity for any imaged artwork, astronomy or not for me anyway. I havent yet found ever an image thwt stays intact from scanner or came 8ra, or iphone (surprisingly good). I may try the graphite drawing as you do and color it in photoshop if only because the color balance in my pastel drawings were , for all intent and purpose, awful. The originals Im proud of. The published end product online was awful. Like my avatar. Oil paintings fair better, my pastel planetary drawings end up with white balance shifts and muddled tones whe re there should be clarity and fine blending. And i draw jupiter with a 5" disc. This time around with Saturn imdefinately going a different route.

Superb work Dave.

Pete

Edited by azure1961p (04/06/13 09:51 AM)


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: azure1961p]
      #5781679 - 04/06/13 12:07 PM

Much appreciated Pete, thanks:

One thing I quickly found when first trying the computer-colouring method is how grossly wrong the judged hue turned out to be. For example I might decide a pale lilac fill (Corel Draw pre-prepared vector) might be close for ring A, but when applied has to be desaturated considerably. This can be done by holding down control on one of the greys; left-clicking adds small increments of the chosen grey. Then the same procedure with an appropriate colour to achieve a closer hue to what was seen. In addition belts and zones (vector fills) can be adjusted against each other to get a nearer relative hue. E.g. I once judged a broad dusky band on Uranus (!!) as of warm brownish hue. Had I been using pastels would I probably have used a small amount of terra cotta + grey/brown; but after being satisfied with the relative hues the Corel colour-sampler indicated the band an olive-brown hue but it looked reddish-brown in relation to the general cyan hue on the monitor! I have a totally black work-area/background when pursuing this. The computer being in the house some 20yds away entails a lot of to-ing & fro-ing so a certain ability of carrying the general view/hues in the head is desirable, but manual drawing-media method demands much more on the memory even if you get down to it straight after – and of course there is the scanning nightmare!!

Colour work is a veritable mine-field and many many variables: futile to claim absolute colour; ball park is the best aim I feel. I have already used a lot of words to describe relatively basic/simple procedures; and it would take pages to relate what is involved with what I am seeking tinting my drawings.

I am finding a basic Kodak Easy Share camera ideal as a substitute ‘scanner’. A discard from our son Stuart after he moved to DSLR! Inserting an SD card in the PC quicker and simpler than scanning.

David/Dave (either - been called worse!)


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Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Saturn April 4 new [Re: David Gray]
      #5781850 - 04/06/13 01:07 PM

David, thank you for the outstanding reply on Enke. Fascinating. I am impressed with your observation and account of it. You're description is of a true observer of planets.

I thought I observed Enke once in a 6" Mak. But after some research and a lengthy thread discussing it, I determined it was not very likely observed. Highly improbable, in fact. Enke minimum, however, will suffice.

Not to get off topic, but some manipulation to get it just right or to display well is fine. Observing is the result of long periods of careful study, it's not nice to ask your audience to do the same work studying a "realistic" sketch.

Outstanding work, David.

Edited by Asbytec (04/06/13 01:37 PM)


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: Asbytec]
      #5781947 - 04/06/13 02:08 PM Attachment (13 downloads)

Quote:

I thought I observed Enke once in a 6" Mak. But after some research and a lengthy thread discussing it, I determined it was not very likely observed. Highly improbable, in fact. Enke minimum, however, will suffice.



Many thanks Norme:
If you had good faith, and with all due caution, in your observation at the time I would say stand by it. 6” scopes do remarkably well in skilled hands (S.W. Burnham: 0.2” doubles elongated etc) Some cynics conceal many explaining-aways beneath their comfort- blankets. I saw someone on the first locked Uranus (“…Season…”) thread virtually talked-out of his Uranus drawing, which accorded well with my impressions around that date.

In earlier days there was a dictum “draw only what you actually see” even if you suspect an illusion. If there is a strong feeling of illusion note it down as a cautionary: someone else may have independently recorded your ‘illusion’; then there is a chance of mutual confirmation. Taking this principle to its extreme, if one night I found that the turbulent Jovian atmosphere had produced markings that looked like “Hi There” (not impossible) I should draw it as I see it. Imagers would soon sort this one; but just to demonstrate.

Please pardon if I am telling you what you already know/practice. But simply stating my strong views.

The late Andy Hollis had strong views with this all this: note the last paragraph in his letter attached. I have hidden the name of a very experienced (still living) observer to spare his blushes!
Dave


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Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Saturn April 4 new [Re: David Gray]
      #5782820 - 04/06/13 10:36 PM

David, your sketches of Saturn speak of your ability to work at the edge of uncertainty, that realm just beyond what is physically possible for most observers. That can only come with practice and probably some genetic disposition toward observing. I recently learned to observe planets through patients and long hours at the eyepiece. Shy of any known genetic advantage, the hard work really paid off.

It is possible to observe what others cannot or might doubt. Sure, record what you see and note observations. I've tried to be aware of optical illusions such as the mach effect. But those illusions are much easier to see on an internet web site than picking the illusion from Martian maria.

Jupiter and Mars were amazing during their recent flybys. I am afraid I will miss Saturn during our short dry season and being away on travel.


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ericj
professor emeritus


Reged: 02/17/05

Re: Saturn April 4 new [Re: David Gray]
      #5783700 - 04/07/13 12:29 PM

Wonderful sketch as always David thank for posting it.

Best,

Eric Jamison


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idp
sage


Reged: 08/21/09

Loc: New Haven, CT
Re: Saturn April 4 new [Re: ericj]
      #5784145 - 04/07/13 03:51 PM

Quote:

the IAU compounding the silliness by calling an impossibly fine line even nearer Ring A’s outer edge the Keeler.




Glad to know I'm not the only one to be bothered by the silliness of the UAI nomenclature. When I wrote reports on Saturn for the Italian Astronomical Union I tended to call "Encke minumum" the large, easy shading at the center of A ring and "Encke gap" what used to be Keeler's gap, just to avoid confusion.

Quote:

Saturn’s rings seemingly being particularly prone.




Indeed

Quote:

Attached is about the best view I ever had of Saturn.




Awesome. I've always been stunned by your draftsmanship. I remember too the green hue around the polar region in 2003. I've given up trying to get a decent digitization from a scanner, I just take a digital shot - which of course has its drawbacks too.

I'm also intrigued by the bright spot in the temperate zone; how "visible" was it? Could you definitely see its rotation?

Great to see your works on this forum.

Ivano


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: idp]
      #5785322 - 04/08/13 06:38 AM

Quote:

I'm also intrigued by the bright spot in the temperate zone; how "visible" was it? Could you definitely see its rotation?




Many thanks Ivano:

Not sure if the spot is real; but was more certain of a mainly slight scalloping of the NTB n. edge. There being a deeper more apparent indentation/bay that I followed to the CM from early in the session: NTB thicker and darker p. & f. the light ‘spot’. We are familiar with this effect on Jupiter: where any real lightness can be contrast-enhanced. So possibly illusory and perhaps made a little too apparent/light through artistic incompetence/carelessness. Actually it is less apparent on the full-res version (300 dpi) on the monitor, and the original drawing!

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.

2003 drawing: I think I defined the green hue as “a duck-egg-bluish-green” or some such and it was striking to a lot of observers I recall.

Very much like your drawings too; and would like to add I feel honoured to be among some very accomplished artists on this forum – though for myself I like your term "draftsmanship"! My late mother and, very especiially, her sister Florence (Raine) (Aunt Florrie: 1892-1931 [d.tragically]) were the real artists of the family

David.


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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
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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
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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
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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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chrisrnuttall
Professor Emeritus


Reged: 12/29/10

Loc: York, England
Re: Saturn April 4 new [Re: chrisrnuttall]
      #5794766 - 04/12/13 03:38 PM

Oh, btw David, my wife is an English lit teacher, up to A-level, with a degree in English lit.... and she can't help with your poet, sorry!

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David Gray
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Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: chrisrnuttall]
      #5794904 - 04/12/13 05:01 PM

Quote:

Oh, btw David, my wife is an English lit teacher, up to A-level, with a degree in English lit.... and she can't help with your poet, sorry!




Yes thanks Chris and zilch from Google. I know I saw the quote years back in S&T: the poet's reference to astronomy as "the cold star bane............" and seemed to remember Blake as the offender but Google has cast doubt!

When are these clouds going to shift - I'm getting observing withdrawal again and it makes me tetchy!

David.


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Asbytec
Guy in a furry hat
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Reged: 08/08/07

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Re: Saturn April 4 new [Re: David Gray]
      #5795363 - 04/12/13 08:52 PM

Quote:

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”!

David




David, I hope you know that is not the context of "art" I was referring to. You do seem to take "accurate" measurements of the planet and make them beautiful to look at. I guess you could put numbers all over it, or list them as bright or vey bright. That would be more technical and less artsy. I prefer you keep up the good work.

I like Ivano's take on it.


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David Gray
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Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: Asbytec]
      #5796086 - 04/13/13 07:38 AM Attachment (11 downloads)

Norme,
Artist/artistry/art/draughtsman: perhaps I have come across as making too much of a deal on this. I will say at once that I have gratefully taken all the complimentary remarks on here as genuinely felt – even in my most paranoid moments!! I can usually spot the insult wrapped in a compliment type! No problem with “art” comments: my mother and aunt Florrie would be proud! Should hear what some back at the bakery called me!

When I commence a session I always try to routinely do intensity estimates of every feature I am sure of: could be 30 or more. Including some that are not strictly required on the BAA Saturn programme. I regard this as an essential prerequisite to doing drawings; after completing this I believe it gives more feel for getting the tones right on the drawing. It also leaves open the possibility of doing a retrospective drawing in special circumstances/requirements. So with every drawing, in the main, there is an accompanying prior one with “numbers all over it”: see attached!

David.


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idp
sage


Reged: 08/21/09

Loc: New Haven, CT
Re: Saturn April 4 new [Re: David Gray]
      #5796106 - 04/13/13 08:14 AM Attachment (9 downloads)

I Counted 37 estimates on that sketch, and seeing was just average! Speaks volumes on how diameter helps on Saturn (and maybe on the advantages of a binoviewer, too?).

That's more or less the best I could do on Saturn with an 8" newton, but in excellent seeing, with rings wide open and when I didn't travel much. Then I started graduate school

Just a "technical" question: I assume like usual dark background sky = 10 and RingBinn = 1 (when rings are open enough), then I find it troublesome not to have an intermediate reference. Do you find the same? How do you manage?

Steady skies,

Ivano


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David Gray
sage
*****

Reged: 08/06/12

Loc: Co. Durham UK
Re: Saturn April 4 new [Re: idp]
      #5796181 - 04/13/13 09:11 AM

Quote:

Just a "technical" question: I assume like usual dark background sky = 10 and RingBinn = 1 (when rings are open enough), then I find it troublesome not to have an intermediate reference. Do you find the same? How do you manage?




Yes sky=10; but BAA has B outer (adjoin. Cassini) taken as 1 but I feel this is too variable throughout an apparition to trust: earlier I even got it as dull as 2.5; and brightens markedly around opposition (Seeliger). An intermediate would be nice: best I could think of is limb-shading - but dicey I reckon. I suppose it comes down to a lot of practice, and as I said earlier here I guess my baker's ovensmanship (50 yrs.) has given me more than a little edge with intensity judgement!

Can't believe it; turned nice outside - may be gone a while. Even longer if it clears (against forecast) tonight!!

David.


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ericj
professor emeritus


Reged: 02/17/05

Re: Saturn April 4 new [Re: David Gray]
      #5796561 - 04/13/13 12:43 PM

Hi David,

Thanks for all of your sketching suggestions. Very interesting.

With regard to eyepieces for the planets here are a couple of articles I have written on comparisons of different eyepieces I have used over the years:

http://ejamison.net/equipment_reviews.html#2

It includes:

Zeiss Abbe Orthoscopics, Pentax SMC Orthoscopics, TeleVue Plossls, and University Optics Orthoscopics compared

Clave Plossls compared with TeleVue Plossls, Brandon Orthoscopics, and Aus Jena Orthoscopics

Clave Plossls compared with TeleVue 9mm Nagler

Clave Plossls compared with Zeiss Abbe Orthoscopics and Pentax SMC Orthoscopics

University Optics Orthoscopics compared with TeleVue Radians

Also TMB Super Monocentric Eyepieces:

http://ejamison.net/equipment_reviews3.html

Best,

Eric Jamison


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