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Mars Climbs…….

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#1 David Gray

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Posted 16 October 2018 - 12:30 PM

Now getting as high as 15º from here and there has been an improvement of definition recently. I can now get it some 2 hours before the meridian but with the big scope’s full aperture still partly blocked by fence & wall structures till an hour or so before culmination.  As the higher/co-mounted 3” is not affected by those I have been starting sessions post sunset getting some detailed views with that.  Also with the 3” stopped down to 1½” (38mm) with fair detail apparent.

 

My impression re the dust storm aftermath is that perhaps some 60% of the main darker features are about up to 60-70% of their usual intensity.  Some like Sinus Sabaeus possibly near normal; but the narrowed Syrtis Major has not yet struck me as particularly dark as I know it can be.  The still-low elevation conditions possibly a factor affecting my judgement……….

 

Being so low we see through a considerable column of air and, even if relatively steady and transparent, a larger number of lofted particulates along the path and reducing contrasts are very likely.  That is adding another dimension to rating seeing/transparency……….after following planets etc. many times through low skies there is what I have called a crispness factor which seems to improve when they reach >20º-25º altitude seemingly due to those airborne motes not so much taking the contrast-edge off otherwise good conditions…….

 

On the attached is firstly a panel of selected views with the 1½” aperture, and from last night the non-masked views with 3” & 16.3” scopes……….all from relatively good conditions.

 

Dave. (In Haste - back soon.....tongue2.gif

Mars 2018 Oct Cmpl.jpg

 


Edited by David Gray, 17 October 2018 - 03:37 AM.

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#2 Kris.

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Posted 16 October 2018 - 01:37 PM

Excellent panel of sketches David waytogo.gif

Your 3" october 15 sketch does a much better job at showing what i saw than my sketch using the 12" lol.gif

How do you achieve the smoothness/blending of the markings on the disk? Do you use pencils or a digital drawing program?



#3 Sasa

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Posted 16 October 2018 - 03:28 PM

Excellent results, David. I appreciate the comparison of views in different apertures. This is excellent reference point to which I can compare my observations. Tonight, I was observing Mars at C.M~325 deg (close to your Oct 14 sketch).

 

https://www.cloudyni...-2#entry8894460

 

I can confirm that Syrtis Major was much less striking to what I remember from past apparitions.  The darkest albedo feature seemed to be in 60mm refractor the rim around southern cap. Hellas was also quite well defined.



#4 Uwe Pilz

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Posted 16 October 2018 - 11:10 PM

Thank you for your sketches. They give a good impression what to expect at an instrument of moderate size.

 

The SCP is very distinct. It still melts down, but usually there is always some remaining (in contrast to the NPC). This can be observed easily, and your sketches show how large (or small) the SPC still is. The increasing height above thh horizon helps.



#5 David Gray

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Posted 17 October 2018 - 08:44 AM

Thanks Kris, Sasa, Uwe and those who Liked……

 

How do you achieve the smoothness/blending of the markings on the disk? Do you use pencils or a digital drawing program?

Kris:  I get those blends from stump-painting the features in broad outline first – that is contrary to the usual practice of drawing them in with the pencil first.  This is done by applying a patch of graphite (from HB pencil) and then picking that up on the stump then applied to the drawing area. 

 

In short: one stump stroke saves many pencil ones!  Three stump sizes mainly used: small medium & large…..medium and small mostly. At times I use for very fine detail/areas those compressed paper lolly sticks sharpened to a point; also a fine pointed 2H pencil can be used to ‘tickle’ in/out a tiny ‘flaw’/spurious-detail that the stump can’t get at……

 

With this method those kneaded/putty rubbers need avoiding as they leave a residue that happily grabs the graphite off the stump; leaving a mark nigh impossible to remove……….

 

Back in the mid-1990s I graduated to that method rather than pencil-first then stumping and found I at least halved the time of getting a sketch, and virtually completed at the scope.  No need to ‘touch it up’ later…..Simply: eliminating the need to stump/blend-out inadvertent pencil marks later if you do not put them there in the first place……!  Thus I get the more natural look of the planets etc. there and then and much more quickly than pencil shading.

 

Retired these 9-yrs but initially this was to suit my work-day/night(shift) commitments – often coming home too tired or uninclined to spend time on working up drawings that were no longer fresh in the mind that had to be left – often with my post-observing early morning (or nightshift) starts or other reasons……

 

To get the smooth blends I do is simply down to using a fine-texture paper: cartridge paper being unsuitable for the technique; and also mostly abandoning such as Bristol and Ivorex Board. I have been using 100gsm Xerox Colotech inkjet paper (A4); this also resists the dampness of the night air much more than those others. Also it is more scanner-friendly for some reason – tho’ digital camera shots are always preferred.

 

A further technique for very smooth blends (Venus, Uranus etc.) is to firstly rub the blank drawing area all over with a small wad of tissue (Kleenex) paper in tight circles (much as the actual stumping).

 

Although I no longer use the inversion method for Comets, DSO and such – the attached demonstration (posted somewhere here before) describes the method as with planets.

 

Dave.

HB Stump.jpg


Edited by David Gray, 17 October 2018 - 08:47 AM.

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#6 niteskystargazer

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Posted 17 October 2018 - 10:33 AM

Dave,

 

Very fine sketches of  Mars Climbs……. smile.gif .

 

CS,KLU,

 

thanx.gif  ,

 

Tom



#7 Kris.

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Posted 18 October 2018 - 04:03 AM

Thanks for the elaborate explanation David!

 

I had a feeling standard printer paper was unsuitable for fine blending… Also the scanning apparatus has a big influence: on the actual paper drawing the blending can be acceptable, but the process of scanning can be so unforgiving and magnifies any ‘roughness’ in the paper making the scanned image very grainy. I then have to smooth it digitally using gaussian blur technique to make it restore the smoothness like on the actual paper drawing again. but alas this also blurs the finer detail and just messes up the sketch!

 

Come to think of it, I didn’t have this issue with my old (broken) home scanner: draw and scan, didn’t need to blur it afterwards, the scan and drawing were very similar.

 

Nowadays I scan sketches using the big scanner/copier/printer at work making it very grainy, and I have a lot of patching up to do, hence why all of my scanned Mars sketches from 2015 onwards look very different from each other in color, contrast and sharpness/smoothness… compared to those of ‘09/’10, ‘11/’12 and ‘13/’14.

 

Might have to change my technique/paper source as well…



#8 David Gray

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Posted 18 October 2018 - 06:46 AM

Thank You Tom.........smile.gif

 

I had a feeling standard printer paper was unsuitable for fine blending… Also the scanning apparatus has a big influence: on the actual paper drawing the blending can be acceptable, but the process of scanning can be so unforgiving and magnifies any ‘roughness’ in the paper making the scanned image very grainy. I then have to smooth it digitally using gaussian blur technique to make it restore the smoothness like on the actual paper drawing again. but alas this also blurs the finer detail and just messes up the sketch!

 

 

Kris:  It’s the troubles you describe that led me to what I do now.

 

I see nothing wrong using a computer to bring the scan-despoiled sketch back to match the original and in my case Corel Draw has many ways of doing that. 

 

Straight forward in theory; but often I found myself spending over an hour (several...blush.gif ) digitally trying to match the originals that often only took me ten minutes at the scope.  Ending up stressed out of my head with a feeling of betraying the old-time principles of messing with the actual sketch itself.

 

Ultimately I decided to mouse-sketch copies, but apart from the time factor (life is too short!) they always looked ‘plastic’ to me. In fact I can go back to the time I had that ‘great’ idea…..see this Link…….

 

http://alpo-j.asahik...11/u110121z.htm

 

Getting increasingly dispirited over the results one day I tried the digital camera……..as related on this Link……

 

http://alpo-j.asahik...12/u121212z.htm

 

Still essentially the same procedure to date; and natural sky (not sun) light works best.  I usually take the swivel chair to the best lit part of the room, mount sketch, rotate the chair for best lighting angle and take a few shots from about 8-10 feet and pick the best from those.  No messing with scanner settings and all just simply the SD card camera to PC.  If hurried to ‘scan’ the sketch when still dark an artist’s daylight bulb in the desk lamp serves pretty well – but natural has proved best.

 

A lot of words this and previous post to describe it all; but in actuality 20-30 minutes from sketch-start: scope-to-posting has been done on occasion

 

Dave.


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#9 Sasa

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Posted 18 October 2018 - 07:38 AM

I ended up with using digital camera as well. The problem is with uniform background, as you described David. Especially in case of DSO. Not only you need to take the snapshot at good lighting, not to get some gradients (from my astroimaging days, when one fights with gradients all the time, I learned how to get most of it, using PixInsight). But the paper has to be well preserved as well, which is not the case of my logbook pages. Otherwise one has discrete jumps in background which are very hard to get rid of.

 

I tried using scanner we have at work, several times. As Kris was saying, the result was very bad. In one case, I used it intentionally. I wanted to  add "vintage" look to my sketch of NGC7027

 

https://www.fzu.cz/~..._30/NGC7027.jpg

 

I wanted  the result to look like old Curtis sketches of planetary nebulae ( http://stars.astro.i...sow/N7027bw.jpg )

 

Nowadays, I have so little time that if I don't finish the electronic version of Mars sketching the very same night, there is little chance that it will be done later. I still have several raw sketches of some DSO objects from this summer that are waiting to be processed...


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#10 Kris.

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Posted 18 October 2018 - 09:06 AM

Before recently, when I started using the scanner at work, I also shortly used a digital camera to digitalize my sketches. I found it very frustrating because I never could get a good result, lighting was never uniform, with flash/without flash, never got the balance quite right. I have no experience with cameras or lighting techniques…

Really considering reinventing my sketching technique here, but the scanner at work will have to do for now…

 

Here’s a comparison showing my latest sketch with scanner at work (notice the attempt to lower the grain with blurring, and the bleak, poor colour depth), a recent one using the digital camera (smoother, more colour depth/differences, but overall colours are off, and one from 2008: simply scanned and untouched, very similar to the original, more colour differences and some fine/sharp details while overall quite smooth. It would be nice to get back to those!

 

Summarized, it’s nearly impossible with big scanners to preserve the combo of smoothness + sharply defined borders/details which was originally on paper.

 

https://www.cloudyni...5_324_83727.jpg


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#11 azure1961p

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Posted 27 October 2018 - 11:59 AM

Yikes Ive been away too long and missed this.  Again Dave, your are fearless in your low altitude forays.  This is a snapping assemblege of observations.  I truly am glad you are getting improved altitude to work with and persevering despite some obstruction issues.    I'll remember this apparition as the Big Bland One.  And of all times to throw up a $/&#* global dust storm.

 

Pete



#12 azure1961p

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Posted 27 October 2018 - 12:01 PM

On the Hale Bopp *onion rings* - you know I did see them with my 70mm Ranger that cold winter. Not to your resolution level but let me tell you, the little guy put up a very fine little image of that phenomenon. Thanks for the views! 

 

Pete


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#13 clay1022

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Posted 28 October 2018 - 11:52 PM

outstanding work David, as always, i like that you compared the two scopes as well, nice job!

Clay



#14 David Gray

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Posted 29 October 2018 - 10:57 AM

Thanks Pete, Clay & All….

 

The planet coming good again after some recent vile seeing during the nights twixt getting the two sketches. Also not great weather recently; even a brief blizzard Saturday morn……….!

 

Conditions good enough now to get >500x with climbing Mars but mainly 385x with these offerings.  With the lower power the ADC is really helping eking out those more subtle tints - which get somewhat flattened in these lo-res postings.  For e.g. an ochrish cast in the south third of the disk might be lost on some screens??

 

Pete: Hale Bopp really delivered for me back then – lots of beautiful structure…...need to dig out some dozen or so drawings and post sometime – some pencil some pastel.  Another bright one would be nice given the additional optics I now have……..20x100s etc.

 

Dave.

Mars 2018 Oct 17 28.jpg


Edited by David Gray, 29 October 2018 - 04:30 PM.

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#15 chrisrnuttall

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Posted 29 October 2018 - 03:50 PM

Lovely work Dave, you are getting some incredibly subtle tonal variations in the deserts e.g. around the outer edges of Hellas, and through the equator north of Cimmerium.

I also notice that you are rating your seeing as Ant II, conditions I have experienced only once these past few months.

Are you observing in white light too?

I'm thinking your ADC is making a big difference!



#16 David Gray

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Posted 29 October 2018 - 04:20 PM

Thanks Chris........

 

White light: you mean sketching with?........can't abide red at any level - seems I'm that sensitive! 

Other than for critical colour work my preference is yellowish-green.  For many years a 12v Christmas

tree light on a 9v battery was what I used till it gave out.  Since simply a 6v bicycle dynamo bulb on a

variable mains adapter covers most needs. 

 

Yes I'm delighted by that ADC; more than I expected too.......!

 

Dave. 



#17 frank5817

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Posted 30 October 2018 - 01:04 AM

David,

 

Very impressive work. Even as Mars falls towards 0 magnitude, it is so bright that I need a polarizing filter to improve contrast and cut down that brightness.

You must be thrilled as Mars has climbed in your sky.

 

Frank :-)



#18 chrisrnuttall

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Posted 30 October 2018 - 03:13 PM

Dave, no I meant are you observing in integrated light, i.e. without colour filters.



#19 chrisrnuttall

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Posted 30 October 2018 - 03:14 PM

i'm liking the idea of using fairy lights as an observing aid though ;)


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#20 David Gray

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Posted 30 October 2018 - 04:53 PM

Thanks Frank……..
Yes good to have Mars clear of the obstructions at last…..smile.gif

 

Dave, no I meant are you observing in integrated light, i.e. without colour filters.

No filters for this type of sketch Chris – I guess I had better make that clearer in future…..Always ensure to state when I do – so should be doing likewise when I don’t!blush.gif

 

In fact when I’m seeking to render colour as seen in IL I try to avoid prior viewing with filters as that can upset the white-balance as much as using non-white lighting.  For e.g. after using say a #25, non-filtered Mars looks almost pure yellow for some time.  Tho’ I’ve found I can reset my vision quicker by looking awhile with a #58; but as I say I resist filter-first under normal circumstances.

 

Dave.




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