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MarkVIIIMarc

Uranus through a 10" Dob, what to expect

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Previously after reading the EXCELLENT "What Can I Expect to See" and a few threads I assumed Uranus would appear to me as at best a blue star like object.  I THINK I recall others even posting they were sketching star fields to make sure they actually saw Uranus.

Then tonight I was goofing with Stellarium and put Uranus in the scope view and it shows Uranus as a blue disc with a couple moons possible to view.  I find Stellarium to be quite realistic in my Saturn and Jupiter views except the moons on Stellarium are discs not points of lights.

Which will Uranus be in my Z10 @ 200-300x?  A blue orb with a moon or two I can identify or a blue star like point of light I'll have to sketch to see if I really saw it.

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Uranus can definitely be seen as a small green disk in a scope of that size and you might be able to pick out the larger moons if the seeing is very good. The moons will be much dimmer and less obvious than those of Jupiter so it is worth using Stellarium or something similar to predict or confirm their position to avoid thinking you have seen a moon that is actually a very dim background star.

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Uranus can be seen like a small green disk and you can tell for sure that it is not a star. It is a stable small green disk. It's amazing actually. Give it a try.

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I will definitely give it a try then.  

We had a relatively cool night with pretty good skies.  Hopefully that is a good sign as we get away from the humidity of summer and head for fall.

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watched it the other night in my c8, looked like a blue (not greenish) featurless disk. almost like a planetary nebula, but not fuzzy.

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I saw it for the first time last year with my 10" dob, it's certainly worth a look. I too saw more of a blue disc rather than green. I couldn't see any moons, probably a bit too faint for my skies.

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As I've posted on this subject before, I'll do it again:

Uranus & Neptune both appear as different colours to different people. Some of this 'colour-changling' behavior could be attributed to it's being at different altitudes above the horizon for different peoples' locations. But even side-by-side the changing colour remains a source of their fascination to me. The best answer I can give regarding the cause of this is thus:

The Human ability to see all the different colours we do is the last major 'sense' to make an appearence in the animal kingdom. Most animals only see in black & white - and maybe red. If you've ever read Homer's Odyssey, you may recall the passage where he describes the colour of the ocean as being 'burgundy' coloured. So when I say it's a recent development of our senses, I meant really recent! And of the planets, none other than Uranus bears this out so well. Many see Uranus (and Neptune, though to a lesser degree) as being blue. Others see it as green. And the shades can vary dramatically. Results using the Munsell Color-System* are all over the map. Some folk even see it as being grey.

Personally I see Uranus as a Dutch Pea-Soup green. Neptune rings my bell as being what I call an Icy-Blue. My best view of both planets was at around 200X in my 12" LX90. Uranus was a good and unmistakable disc. Neptune was discernable as a disc, though an untrained eye might have thought it was a very bright star. The Moons seen were points of dim light.

And on this note,

Dave

Munsell Color-System.jpg

 

https://en.wikipedia.org/wiki/Munsell_color_system

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Animals see in a vast variety of colour depending upon their order. Maybe it was tongue in cheek, but are you seriously suggesting that colour vision in humans has evolved dramatically in 1000 years?

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Homer was blind, perhaps someone was pulling his leg and described the sea as 'burgundy' to him :)

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20 minutes ago, Moonshane said:

Animals see in a vast variety of colour depending upon their order. Maybe it was tongue in cheek, but are you seriously suggesting that colour vision in humans has evolved dramatically in 1000 years?

According to this our eyes evolved to a state where they could see the full spectrum of visible light about 30 million years ago...

https://en.wikipedia.org/wiki/Evolution_of_human_colour_vision

 

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I know people who are effectively blind to colours today. While I know others who see red, yellow, orange, and other shades and graduations of these as being the same colour. This sort of "deficiency" is screened for when you go in for a pilot's license for aircraft.

It makes for a fascinating field of study. In fact my father was a professor at MIT in Cambridge, Massachusetts, USA - and the application of colour in arts & design was what he taught and specialized in. Such is what lured Yours Truly into the study of this field as well. I was the 'black-sheep' of my family though - opting to study sciences instead of the arts. But I digress.....

Back to Outer Gas Giants?

Dave :p

Edited by Dave In Vermont

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You can see Uranus with a simple binoculars 10x50, and you will definitely be able to see it as a blue / green / grey disk at higher magnifications than 100-150x. 

Regarding the moons, I haven't been able to spot any moon at any magnification (tried up to 375x) with my skyliner 8" in 4-5 nights of very steady but light polluted sky (SQM: ~19 mag/argsec^2). Uranus' moons are dim targets (>13.5 mag), so sky transparency and darkness might make a difference. 

Will 2 additional inches in aperture help you with this? :dontknow:   I suspect they will if you give it a go under a sufficiently dark and steady sky. :rolleyes: 

Interesting test! :) 

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On 9/5/2016 at 15:45, Piero said:

You can see Uranus with a simple binoculars 10x50, and you will definitely be able to see it as a blue / green / grey disk at higher magnifications than 100-150x. 

Regarding the moons, I haven't been able to spot any moon at any magnification (tried up to 375x) with my skyliner 8" in 4-5 nights of very steady but light polluted sky (SQM: ~19 mag/argsec^2). Uranus' moons are dim targets (>13.5 mag), so sky transparency and darkness might make a difference. 

Will 2 additional inches in aperture help you with this? :dontknow:   I suspect they will if you give it a go under a sufficiently dark and steady sky. :rolleyes: 

Interesting test! :) 

I need to take a field trip out to central Missouri and get some dark sky time in is what it sounds like.

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3 hours ago, MarkVIIIMarc said:

Interesting link.  30 million years ago was half way back to T-Rex, KT is 65 mya, right?

Yip.

Here is a link to the research paper cited in the Wiki article: http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004884

Apparently our ancestor at that time looked something like this...

200px-proconsul_nt.jpg

 

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I like the Munsell scale link.

I normally see Uranus as:

2.5BG9/8 or 

R 114

G 251

B 233

From my NELM 5.5 garden I can catch moons !!!

Paul

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I recently read an article suggesting that you can't see a colour unless you have a name for it. May sound silly, but it went on to describe a tribe that doesn't have a name for the colour blue, so when shown 7 green spots and 1 blue one, they struggled to identify the blue spot (which I \We could easily identify); conversely, this tribe has different words for different shades of green, so when shown a bunch of green spots with one a very different shade of green, they easily found it (whereas I struggled).

The word blue didn't exist when Homer wrote the Odyssey, and this is a suggestion as to how he experienced the colour of the sea.

Not sure how exactly this relates, but I maybe your own experience of colours has something to do with how you see it.

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On 9 September 2016 at 20:58, rockystar said:

I recently read an article suggesting that you can't see a colour unless you have a name for it. May sound silly, but it went on to describe a tribe that doesn't have a name for the colour blue, so when shown 7 green spots and 1 blue one, they struggled to identify the blue spot (which I \We could easily identify); conversely, this tribe has different words for different shades of green, so when shown a bunch of green spots with one a very different shade of green, they easily found it (whereas I struggled).

The word blue didn't exist when Homer wrote the Odyssey, and this is a suggestion as to how he experienced the colour of the sea.

Not sure how exactly this relates, but I maybe your own experience of colours has something to do with how you see it.

Do you still have a link to the article Lee. Think it might be usefull to many of us to rwad and see if this apparent strange phenomenum affects us all!

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My 180 Mak shows Uranus as a defined, blue-white disk, and Neptune as a little bluer and smaller, but clearly a disk. Interestingly, my 127 Mak shows slightly more intense colours on Uranus, but not on Neptune - must be a feature of old eyes!

Chris

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I can see Neptune and Uranus as defined disks with my 4" refractors but quite a bit of magnification is required, especially on Neptune where the planetary disk is just 2.3 arc seconds in diameter, which is around the separation of the star pairs in Epison Lyrae, the famous "Double Double". Their colour tints are apparent but rather washed out in smaller apertures. With my 5.1" refractor the colour tint is more obvious and I've managed to see Neptune's brightest and largest moon Triton using averted vision. With my 12" scope the colours are clearer again and Triton can usually be spotted with direct vision although it's still a very faint point source. I have also managed to spot the moons Titania and Oberon around Uranus with the 12" scope but these are slightly fainter than Triton so a real challenge even with the 12" aperture I find.

The most striking colouration of Uranus that I've witnessed came when it was very close to the Moon a year or so back and I could get both the bright lunar lumb and Uranus in the field of view at 199x with an ultra wide eyepiece in my 12" scope. On that occasion the Uranian disk was remarkably colour saturated I thought and really very beautiful as it appeared to hang in space just above the lunar limb and rather like the famous Apollo 8 "Earthrise" photo albeit with a much tinier planetary disk and one that was considerably further away than the Moon of course !

I've often wondered since whether the strong colour was a product of having the bright lunar segement in the same field and since then I've taken a different view on the need for dark adaptation when planetary observing (or not !) :icon_biggrin:

Edited by John
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To see the real colour of the planets, just defocus them.

U can see the proper green & blue then.

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