Nice views of Uranus and Neptune (Finally)
Posted 29 September 2013 - 11:13 PM
Seeing : 5-7 Pickering
Transp: a little smooth high altitude haze
A very fair view (finally) that up to this point proved often too soft to stand higher magnifications. Here I got a nice 7 Pickering and best overall view at 303x. A tight slate blue pale green orb as it drifted across my undriven dob FOV. It took 450x to see Triton with certainty as transparency isn't great tonight, but the planet again was best at 303x..
Its sobering just how exceedingly minute this planet is at 70x. Its such a close call.
It was easy navigating to this brighter bigger object after having been back and fourth with Neptune the last 6 weeks. It was the best view Ive had in a while...
The face was a perfectly blank warm shade of wooly grey blue. The warmth is that pale yellow in the blue. Calling it green is an overstatement .
I found like Neptune that 303x tonight was a fair magnification. The seeing smeared it often but just the same it would reconstitute and be a tight sharp pale warm blue grey orb. It had a powdery texture. Though I saw no details I wouldn't call this a conclusive view in possibilities of seeing something on a better night.
Moons were out of the question - seeing had OK periods but the transparency while not awful, was poor.
Wrap up: Two very nice proper views of the two outter giants. Reading Schmudes book further enhances the observing experience. Some folks are let down by these two but I find their challenging nature very engaging .
Scroll down for finished renderings of both planets and Triton.
Posted 30 September 2013 - 01:18 AM
I'm seeing some color variations in both swatches, is Uranus north to the left? (Kidding.) Is Neptune really that dark?
Posted 30 September 2013 - 04:17 AM
Nice observations. It's really fascinating to observe those planets...
Regarding the color of Uranus, you may not be able to see the green color if your telescope is a 8" (if I look in your signature). When I was observing with a 7" newtonian many years ago, even under a dark sky the color remained pale blue to me. It was only when I got a 10" that the green tint became accessible.
More over, this depends as well on the sky transparency. With my 10", I do not see the green through my urban sky - the planet is almost grey. But with the same telescope used in the country, the green is visible.
Last summer at the eyepiece of the 620 mm cassegrain of Astroqueyras at an altitude of 3000 meters, the color was very pale green, almost white (!) and absolutely no blue, while Neptune was clearly sky blue.
(of course we may have some differences in our eyes, yet it is curious that observers disagree only about Uranus !)
Posted 30 September 2013 - 08:25 AM
Yes Norme the Neptune image is a little dark . It'd be easier if it were illustrated on a dark background but I did all the editing here on my phone!
Ill probably rework it today. Ill be putting out a finished digital sketch of Neptune and Triton later as well - though not edited with my phone.
Mr. Pellier - thanks for the accounts on your behalf. I completely agree that a darker sky has an impact on how well we perceive color. I find viewing from my condo with all the extraneous light from every angle plus the urban light dome really mutes the colors - particularly on Neptune. From a darker country sky there is this blue/teal that's unique and unmistakeable - but here from the city its merely blue with the barest suggestion of green element. Uranus is a planet Ive never seen through a large instrument but I don't doubt the added light and scale would help that green shine in through. A curious thing is my childhood view if Uranus. I stumbled upon it accidentally with a 4.25" reflector. It mystified me - i had no idea what i was seeing - more over that it defied substantial enlargement similarly vexed me. What I recall vividly still though is the color. Chris to my. 14 year old eyes it was a pale grey with lime green tinges. I had no pre suggestion here - I went to bed that night not knowing what the heck it really was. All that to say I believe the age of 52 has taken away some of the color sensitivity of 14! I later used a planetarium program to the date and time ( approx) and sure enough it was Uranus. How I chanced upon it is pure dumb luck. I think the low power color must've caught me. At anyrate - I agree with your finds - I look forward to a large aperture view one day - and the seeing to realize it.
I noticed color comes in pulses or bursts with small orbs like Titan and these outter two. The tinged of color would pop up almost like morse code sequence then fall back to muddled grey. I'm guessing the off and on pulses of color reception are the cells of seeing focusing and defocusing the light hence the way it would reconstitute in a series of subtle flashes.
Posted 30 September 2013 - 10:39 AM
Posted 30 September 2013 - 10:41 AM
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Posted 30 September 2013 - 03:38 PM
Posted 30 September 2013 - 06:36 PM
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Posted 01 October 2013 - 11:01 AM
( kinda related spooky article here (voyager 1 has since left the solar system) )
Posted 02 October 2013 - 06:52 AM
Pete I feel you have got some pretty near colours for these two planets.
I have to say over the years Neptune has fairly consistently looked to me quite strongly blue, a little more greyish at times. But have often been perplexed by the hues that Uranus has presented. All the way from sky blue to almost yellow. These past apparitions with it getting higher in my skies I see more of cyan, tending more green-ward at times: so yellows might come from low altitude reddening. In fact I reckon that the colours used in the WinJUPOS simulations are pretty good representations for both planets on the whole – at least for my impressions of late.
When I started systematic observing of Uranus back in 1969 March (10” f/8 Newtonian) I was getting striking differences night to night. Often looking quite green; then another night almost sky-blue. Intriguingly when it looked green I was getting faint banding (plus limb shading), in the best seeing, and in equally good conditions it looking sky-blue and quite blank apart from limb shading.
Looking back then I was using a red light (which I always found uncomfortable and abandoned for good in 1970 – preferring ‘white’) and have often wondered if the common use of red is behind a lot of the green hues perceived by others. A pity I have no record of which of those nights I had the red light on….! But the planet is back higher and an experiment is easily set up.
Back in 2007 James Bryan (Texas Uni.) sent me a paper by the late Peter J. Young, an accomplished UK observer, who described his experiences with both planets. He used the following instruments (1974 & 1976): 9” refractor, 12” (Northumberland/Cambridge) refractor, the 36” & 82” reflectors at McDonald Observatory Texas. He had these comments re. their colours - Uranus: “The colour of the disc in the large apertures would best be described as creamy-grey with only a vague hint of yellow or green; the hue is less pronounced in the luminous images of the large reflectors than in the small refractor.” Neptune: “Again the colour was not as pronounced as in the small refractor, best being described as cold grey, different from the creamy grey of Uranus.”
Uranus in particular might well be accentuating individual differences with colour perception??
Posted 02 October 2013 - 05:10 PM
What was surprising is that the color was actually less intense than what I see through my 250 mm. I would have expected the opposite....
Neptune's color was more easy to catch in comparison. Just pale blue.
Posted 02 October 2013 - 09:34 PM
David, I am always surprised at how susceptible color in small apparent orbs like Uranus and Neptune ( Ill add Titan and Io in there too) can be to changes in seeing conditions. That Uranus had shown a different hue when sharp and revealing bands is a nice example of how it resaturates its color from periods of lesser seeing. What's so curious about these things to me is that had I a micrometer to measure the soft focus compared to the sharper focused orb itd be a very close measurement - quite fractional even. But for my eyes anyway its the difference between seeing neutral plain grey and specific color. Lesser seeing seems to desaturate.
What's interesting about the larger apertures showing less color than smaller is that it seems to echo the effects of color with doublestars where a medium aperture might show a nice crimson carbon star tinge while a very large aperture turns it a rusty orange and that snazzy cherry color is lost totally. Perhaps these larger reflectors are bleaching retinal sensitivety and paling some of the colors if not appearing to shift them outright.
The low altitude reddening by the way is an interesting notion . A low altitude Jupiter to me will have a creamy appearance - it'd make send that Uranus would as well. infact, the yellowest I saw Uranus (when I was 14 as mentioned elsewhere) the color was a dead ringer for Christophes Uranus . I had often believed, lamentably, this was an age thing where my 52 yr old eyes can't match my youths even though Ive doubled my aperture. Looking back on it though, it was no more than 25 degrees off the horizon - I had to look through tree branches across the yard. Maybe Ive put too much blame on age?
Thanks for the comments and accounts.
Attached for comparison is the color Ive sen under dark country sky's without the intrusion of lights etc. Itd have this color surface out of the grey that was beautiful actually and unlike Uranus though still, dimmer of course. That blue green under dark sky's and no glare is a very fine sight.
This was a fleeting though reoccuring tinge - the pic makes it seem rather plainer than it actually was.
Posted 02 October 2013 - 10:55 PM
Funny thing, and I think I've posted this before, but at low powers, Uranus looks almost lime green to me, the blueness not registering until I raise magnification. Neptune always seems blue to some level at any power.
Posted 03 October 2013 - 12:50 AM
presently this opposition the planet appears to be creamy-litgh yellow greyish in the 280mm and more greenish in the 127-180mm. Last opposition the coloring was according my observation more greenish.
It seems variating from an opposition to an other and I think our personnal eyes may get different aspect with regards to own eye sensitivity to some color channel.
But these considerations are not coming from photometric measurements.
Posted 03 October 2013 - 02:58 AM
Posted 03 October 2013 - 03:54 AM
Posted 03 October 2013 - 05:07 AM
I have taken issue in the past when certain popularisers wax lyrical about blood-red Mars (and Betelgeuse etc); and have to say if they have blood that colour they need medical attention and would be surprised to see them walking about!
How colours are perceived depends a lot on what we have been looking at just previously to the object in view. During some colour investigations with Titan’s redness I selected a number of similarly bright G,K&M, near-field, stars for comparison. As I thought at times Titan was even rivalling some carbon stars I decided to include some, and found, then, nearby SS Vir – this soon showed me it was way redder than Titan! However I was so charmed by the star’s hue I spent some time just looking at it (415mm/16.3” D-K) – was about mag. 7. Just after that Mars caught my eye toward the west and after SS Vir it looked nothing more than pure yellow (n. eye) and it took some 20 mins. to ‘normalise’.
Further during that investigation Titan made a very close approach to a K star that at first looked more orange than Titan; then as they closed a most peculiar complementary ‘double-star’ effect became increasingly marked. Titan started to look the redder then when they got to c. 15” Titan took on the most strange dull brick-red cast and the star looking little changed – very curious.
These past years I have spent a lot of my observing trying to represent colours I see on planets etc on the computer. Before going on I would like to stress that what I depict is not an attempt (futile!) at absolute/true colour; but simply as I see them. This has taught me much as to how colours are affected against each other. Difficult with art media: the PC allows fine tweaking one shade adjacent to the other/s. For instance some years back I was getting a broad dusky band on Uranus that often conveyed a warm brownish tendency. Had I been using pastels I would probably have applied a grey with a touch of terra cotta. The PC revealed this to be way off (against the general hue) – garish even; and by I had tweaked it to satisfaction the Corel Photopaint colour-sampler revealed it to be a pale olive-brown – regardless of whether it was subjective/real or not in the eyepiece.
Of course how I see colours on my monitor/s probably differs with others – and that is a another can of worms! Once at a family gathering we had my two desktops and four laptops all set to default as an experiment, and we viewed some of my colour drawings on ALPO-J – and they all looked different: colour-wise and contrast & brightness too…..!! Some really dreadful to me!
I should point out that my various colour differences with Uranus were very much in comparable ideal to excellent conditions, In particular I stress that I resist doing drawings of any planet if the seeing is not better than III (5/10): for Uranus, Neptune & Venus no worse than II-III (6/10 – 7/10). Unless some ‘extreme’ phenomenon was apparently ‘poking’ through the turbulence – then an impressionistic drawing would be executed; with appropriate notes.
Ageing eyes: Walter Scott Houston often touched on this in his S&T Deep Sky Wonders. In particular with yellowing of the eye-lens. Which he also put down to smoking, and I’ve seen photos of him with a pipe…!! He used to offer as a test certain planetary nebulae that tended to look bluer to younger eyes and more green to older ones.
I’m 69 and a non-smoker all my life and pretty happy that any yellowing is very minimal – if any. Vega, brighter Pleiades, Orion belt stars all striking blue to me; not greenish or even yellow that some would be saying I’d be seeing at my age. Back in the mid 1960s I used to enjoy the sky-blue hues of NGC 6210 & 6572 and have often revisited them over the years; most recently when I still saw no green in 6210 with 6572 very slightly so – both these have a superficial resemblance to Uranus to me and could ascribe either’s colours to it at various times.
Could go on (lots of worms in the cans) but better stop perhaps other points some other time.....!
I am hoping to put a graphic-type illustration on the Sketching Forum of the colour changes in Nova Del against it's light-curve and included carbon star X Sge. Maybe on soon but hoping the weather forecast is right for the weekend and allows me to add more before posting.
Posted 03 October 2013 - 08:12 AM
Posted 03 October 2013 - 08:38 AM
All sorts keep coming to mind lately from those old S&Ts: keep meaning to get them (100s/jumbled ) back in proper sequence and go through them!
Posted 03 October 2013 - 10:45 AM
Posted 05 October 2013 - 09:07 AM
Next, I slewed over to Neptune and there it was too. Much smaller than Uranus even at high magnification, but still a sight to behold - for me since I had never seen it anything more than a pinpoint. It was sitting there as a solid round little disk.
Posted 05 October 2013 - 11:49 AM
Nice report. You might want to try the Galilean moons next when Jupiter rises to height at an hour you agree with. Even in mediocre seeing every moon subtends a discrete disc at 200x or more and 350x is superb. The latter magnification from my experience needs 7/10 or better seeing. Pretty rare last winter. Titan's another one that subtends a true disc . When the seeing complies 8" can go way down to extremely minute orbs.
I enjoyed your account Jon.