Jupiter in excellent seeing - what is visible visually?

[Stu]

Having had such a great night observing Jupiter on 4th April, I thought I would start another discussion about what I saw and hope that others will contribute too. The idea is not some sort of competition, but to highlight what is possible with different scopes and hopefully for us all to improve and see more in future by knowing what to look for.

John (broadway1) posted up a lovely image from his C14 which he has kindly given me permission to reference as it was taken at the same time I was observing. I always find it fascinating to see images like this as it helps validate and clarify exactly what you were seeing.

John's post is here:

I've attached four images to this thread. The first is a labeled diagram of Jovian features. The second is John's original image, the third is the image with highlighted areas showing what I could see (red is definite and purple is suspected/hard to see), and finally there is a detuned version meant to roughly represent the visual view although this is not exactly successful. It looks much more washed out than the actual view because I have had to knock it back to remove detail I couldn't see. Anyway, hopefully it helps the discussion.

Kit wise I was using a Tak FC-100D on a Vixen GP mount with goto. I used a Baader Zeiss T2 prism plus a Leica Zoom and Zeiss Abbé Barlow giving me approximately x100 to x200 to play with. I found that roughly x180 was the most reliable in terms of the contrast of the fainter features vs image scale so I could see them. I tried a Neodymium filter but didn't think it added any detail although it did boost the perceived contrast.

So, working from the top, the North Polar Region showed as a shaded area, with what I assume to be the North Temperate Zone a whiter band below this followed by the NTB again a lightly shaded grey underneath it. I could not see the NNTB or the zone, both of which are visible in John's image. Next up (or rather down) was the Northern Tropical Zone showing as a paler band above the NEB. Note that I am still unsure whether I saw the NNTB and NNTZ or the NTB and NTZ! I suspect the former but have assumed the latter! Any input and clarification is appreciated. I have the same confusion in the Southern region!

The NEB itself had some subtle wavy detail on its northern edge (highlighted by the purple box). I could see some variation in intensity through it, but the main features were on the southern edge. Ahead of the GRS was a festoon, and directly above the GRS was a dark mark which I thought at the time was a barge. In fact it was just an intense swirl in the turbulence along the southern edge of the NEB as proved in the image. The main features I could see are highlighted in red boxes or ovals on the diagram.

The Equatorial band was fairly featureless, but then we come to the SEB. GRS itself was a lovely orange/brick colour, surprisingly intense. I could not detect any variation within it, that's something I will look for more in future. The lovely white separation between GRS and SEB was very clear, as was the dark 'eyebrow' which ran down from the GRS then all along the lower edge of the SEB. The separation of the SEB was visible as a lighter band running within it, and it was slightly darker towards the top. Following behind the GRS were what appeared to be two white ovals and a fainter feature between them. From the image they appear to be bright swirls in the turbulence following it, but still very nice to detect. Finally, I could just detect some waviness/texture along the top of the SEB.

We then had the Southern Tropical Zone, the STB and STZ and finally the Southern Polar Region. Same situation as in the north though, I could be confusing the STB/STZ with the SSTB/SSTZ. Either way I could see one and not the other. I could not see any white ovals in the Southern Polar Region which do appear in John's image.

So, that's it. A very rewarding session and surprising levels of detail from what is an excellent scope, but still only a 4" one!

Please do add your own experiences be they more or less detailed from whichever scope you used, big or small.

Stu

[Darren Poulson]

Awesome post, loads of details.

For my 2p worth, Jupiter was first light on my first scope, on Friday (1st April). StarTravel 102, on an EQ5 (vastly over spec for that tube, but I want to do astrophotography) and even with just the eyepieces included I got a great view. With the 10mm EP and 2x barlow, could easily make out the four Galilean moons and (thanks to your diagram, I can name them) the north and south equatorial belts. No other real detail could be seen, but for my first attempt I was happy. 

Need to get some more eyepieces, and my camera attached,  

[laudropb]

Very good post. Lots of interesting information. Unfortunately I only managed a 30 minute session before the clouds rolled in and the seeing was not great here.

[Peter Drew]

The first decent view of Jupiter I had with the new to me 20" F3.5 showed the level of detail shown in the detuned image but with sharper outlines to the features so I was pleased to prove that the telescope was capable of some high resolution views as well as revealing faint DSO's. 

[Stu]

1 hour ago, Peter Drew said:

The first decent view of Jupiter I had with the new to me 20" F3.5 showed the level of detail shown in the detuned image but with sharper outlines to the features so I was pleased to prove that the telescope was capable of some high resolution views as well as revealing faint DSO's. 

Thanks Peter. Yes, that was my challenge in detuning the image. The views for me were more vivid and as you say had sharper edges to the detail

[John]

Very interesting post Stu and a great way to correlate the visual with the image.

It sounds like your 4" Tak can discern similar levels of detail on Jupiter to my 12" dob. Maybe I'm going to have to re-think my scope strategy

 

[Piero]

This is a very interesting thread which can collect a lot of good information for observers, I feel. 

Your Tak is an excellent telescope, a dream for many to look through!

With my 60mm, under very good seeing / transparency I spotted the North Temperate Belt, North/South Polar regions and even some festoon. I haven't (yet) been able to spot the GRS even when I knew it was there. When I observed it with the 8" (only two times unfortunately) and Naglers, the GRS was easy to spot and all the other features showed more details. If it will be clear, I will test the Deloi soon at 150x, 200x, 250x, and 300x. The seeing over there can often be very steady for days, so it should be fun!  

[jetstream]

Great information Stu, I love comparing to images myself and I borrowed one to show what I see through the EP. Under the best of seeing the center bands are much sharper than this image shows and the colors deeper.Festoons show a blue/purple color, I must study the map of Jupiter you posted to refresh my memory on the features names. Thanks for posting this info.

 

[scarp15]

A useful template and reference after which, based on observing accounts recently there are some interesting active planetary surface features visible. I was resigned to having to miss the night of the 4th, but did get to haul a scope outside last night on the 5th. Compared to my session last week, surface features were a little quiet, during my brief ninety minute period with intermittent good seeing.  I have been using my 8" dobsonian, last night until about 11.30. I was using powers ranging X120, X150 and X200, my 10mm delos X120 provided the most satisfying on this occasion. I did not see any of the festoons or that dark marking along with the GRS as I had last week, but could perceive the polar regions, indications of the North and South Temperate belts, so pleasing enough.

[Moonshane]

Great post mate. I often despair at poor conditions which often allow only round 120x as per last night but in general I see the same sort of detail you refer to. My issue is that my sketching skills are not good enough to get down what I see half the time although the illustrations help my notes look a bit more attractive to the eye at least. I have never to my knowledge seen a white oval distinctly but the GRS, barges (in previous years) and festoons are regular. I can generally make out the darker, 'wavy' edges of the main two bands and of course the polar regions, often with pale bands through them.

Your post actually made me feel a little better actually as it seems that my eyes are not as dodgy as I was starting to suspect!! 

[Stu]

Cheers Shane.

My sketching skills are non-existent, or perhaps more I just find it too distracting to try to sketch whilst at the eyepiece, I find it easier just to concentrate on what I'm seeing at the time. Perhaps I should sketch from memory afterwards???

EDIT I meant to add that it is strange that barges seem to be missing this year, I distinctly remember plenty of them during previous oppositions?

White ovals have eluded me in the polar regions, the 4th was the first time I had knowingly seen the bright regions in the turbulence following the GRS

[John]

I've not seen much in the way of barges (Jovian !) for the past couple of oppositions. The white spots / ovals in the temperate regions are pretty challenging - I can see the more obvious ones but not the smaller ones that appear in images. When I can see them they tend to wink on and off as the seeing varies but then that applies to the whole planetary observing thing really. It's a rare night here when the full level of detail is available constantly through a session.

If we did our sketches at the worst moments of seeing, the main equatorial belts would be shown but not much else !

[Stu]

1 hour ago, Moonshane said:

Great post mate. I often despair at poor conditions which often allow only round 120x as per last night but in general I see the same sort of detail you refer to. My issue is that my sketching skills are not good enough to get down what I see half the time although the illustrations help my notes look a bit more attractive to the eye at least. I have never to my knowledge seen a white oval distinctly but the GRS, barges (in previous years) and festoons are regular. I can generally make out the darker, 'wavy' edges of the main two bands and of course the polar regions, often with pale bands through them.

Your post actually made me feel a little better actually as it seems that my eyes are not as dodgy as I was starting to suspect!! 

Nothing wrong with your eyes if your new image/avatar is anything to go by Shane ??

[iPeace]

Excellent topic; great info in initial post. Now at least I can put names to details I can't quite see. 

I observe Jupiter using the TV85 (an 85mm F/7 APO doublet), a Baader/Zeiss prism diagonal and TV Ethos eyepieces of 8mm, 6mm and 4.7mm. I currently use an undriven alt/az mount (similar to the Vixen Porta) with slow-motion controls.

I've pretty bad light pollution and am surrounded by neighbours' dwellings complete with working chimneys.

My basic view of Jupiter is a small disk with the NEB, EB and SEB clearly discernible, the Northern and Southern temperate belts and zones more of a gradient and the polar regions as "caps" where the gradients end. "Discernible" doesn't mean that a lot of detail can be seen; the NEB and SEB will show interesting dark smudges of varying shape. The GRS will sometimes appear very nicely discernible against the background of the SEB as a small grapefruit-pink spot, and at the best of times with a border of "white" separation around it. Other times, it won't show at all, even though Stellarium tells me I'm staring right at it. Shadow transits are visible as tiny "bullet holes" and moons in transit are sometimes visible, sometimes hardly or not at all, when they seem to be lost in all the light reflected by the planet in the background. The tiny moons against the background of the surrounding void are (almost?) globular in appearance; they certainly won't be taken for stars.

With the 8mm, all is crisp and sharp. Most enjoyable and very satisfying - and makes me want to increase the power to see more details. The 6mm is a bit more sensitive to the actual viewing conditions, and the quality of the view fluctuates as the conditions do, but even at the best of times, the planet itself seems more blurry than through the 8mm. The 4.7mm potentially provides the most detail, but is considerably more sensitive to the fluctuation in the viewing conditions and renders the planet even more blurry. So the higher the power above 8mm, the more patience one must apply to get those vital moments of optimal - which is not perfect - clarity. And even then, details as blatant as the GRS can fail to show, even when it's right there on the CM - again according to Stellarium.

On the whole, I've had some great views, and am convinced the best are yet to come under darker skies and better conditions. I'm by no means in denial of the fact that the TV85 is more of a jack of trades than a master of the planetary - or any other. Nor do I expect to see as much at this stage as I will later in my career as my brain is trained through observation. The greatest factor in the variance between what I've been able to see is undoubtedly the local viewing conditions.

[John]

I don't think Jupiter needs dark skies or dark adaptation. I usually get my best views of it and it's suface features either in twilight or when I've just come from a well lit room. I often pop inside to catch some light while viewing Jupiter wheras for deep sky objects it's completely the opposite of course.

 

[Stu]

6 hours ago, iPeace said:

Excellent topic; great info in initial post. Now at least I can put names to details I can't quite see. 

I observe Jupiter using the TV85 (an 85mm F/7 APO doublet), a Baader/Zeiss prism diagonal and TV Ethos eyepieces of 8mm, 6mm and 4.7mm. I currently use an undriven alt/az mount (similar to the Vixen Porta) with slow-motion controls.

I've pretty bad light pollution and am surrounded by neighbours' dwellings complete with working chimneys.

My basic view of Jupiter is a small disk with the NEB, EB and SEB clearly discernible, the Northern and Southern temperate belts and zones more of a gradient and the polar regions as "caps" where the gradients end. "Discernible" doesn't mean that a lot of detail can be seen; the NEB and SEB will show interesting dark smudges of varying shape. The GRS will sometimes appear very nicely discernible against the background of the SEB as a small grapefruit-pink spot, and at the best of times with a border of "white" separation around it. Other times, it won't show at all, even though Stellarium tells me I'm staring right at it. Shadow transits are visible as tiny "bullet holes" and moons in transit are sometimes visible, sometimes hardly or not at all, when they seem to be lost in all the light reflected by the planet in the background. The tiny moons against the background of the surrounding void are (almost?) globular in appearance; they certainly won't be taken for stars.

With the 8mm, all is crisp and sharp. Most enjoyable and very satisfying - and makes me want to increase the power to see more details. The 6mm is a bit more sensitive to the actual viewing conditions, and the quality of the view fluctuates as the conditions do, but even at the best of times, the planet itself seems more blurry than through the 8mm. The 4.7mm potentially provides the most detail, but is considerably more sensitive to the fluctuation in the viewing conditions and renders the planet even more blurry. So the higher the power above 8mm, the more patience one must apply to get those vital moments of optimal - which is not perfect - clarity. And even then, details as blatant as the GRS can fail to show, even when it's right there on the CM - again according to Stellarium.

On the whole, I've had some great views, and am convinced the best are yet to come under darker skies and better conditions. I'm by no means in denial of the fact that the TV85 is more of a jack of trades than a master of the planetary - or any other. Nor do I expect to see as much at this stage as I will later in my career as my brain is trained through observation. The greatest factor in the variance between what I've been able to see is undoubtedly the local viewing conditions.

Great post iPeace, thank you. You may be relatively new to this but your descriptions are very detailed and accurate which tells me you know exactly what you are seeing! ??

I used to own a number of Televue scopes, including a TV85 which I loved. It is a beautifully engineered 'nugget', built like a tank and something which will last several lifetimes if cared for properly. Optically I found it very good, though I would say it is a little behind the Tak in terms of sharpness, scatter and contrast. The additional 15mm aperture also has a significant impact at these sizes in terms of the available resolution. I found clear differences in every step up from a 66mm William Optics scope, through the TV76 then TV85.

Coming back to your observations about your observations (??), I do think you would benefit from getting away to a more stable site. As John says, light pollution is not really a big issue for planetary observing, but local and high level seeing conditions are critical to being able to catch the fine detail. Getting away from chimneys and heating plumes, plus keeping an eye on the Jetstream forecast can make a huge difference.

From experience with the TV85, I know that I found benefit in using eyepieces down to around 3.5mm under the right conditions. I used a number of different ones including a Nag Zoom, 3.5mm Type 6 Nag, 3.5mm Delos and 3.7mm Ethos SX. In terms of focal length, I found the Ethos to be about the most consistent as an optimum maximum under good conditions (or the nag zoom at the same f/l but the quality is not quite to Ethos standard). I did not particularly get on with the Ethos eye relief or field of view though and sold it. The 3.5mm eyepieces were lovely but just a tad too short to be optimum much of the time.

Your comments about the stability of image at varying magnification are very accurate and interesting. The same applies to different aperture sizes. I was observing using both 4" and 8" scopes the other day, and the seeing was quite variable. The 4" frac was giving pretty stable images, cutting through the seeing reasonably well, but the 8" was far more variable. When the seeing was at its best, it showed more detail than the frac, but at its worse it was far blurrier, which made the frac more enjoyable to observe with.

Thanks again

Stu

[iPeace]

6 hours ago, John said:

I don't think Jupiter needs dark skies or dark adaptation. I usually get my best views of it and it's suface features either in twilight or when I've just come from a well lit room. I often pop inside to catch some light while viewing Jupiter wheras for deep sky objects it's completely the opposite of course.

 

That's just as well, at least for this location...I've tried intermittently exposing my eyes to even more light during sessions with Jove, but haven't noticed much difference - possibly because the plentiful neighbourhood lighting is already giving me maximum 'benefit'...? I'll keep experimenting with this in due course.

[iPeace]

1 hour ago, Stu said:

I used to own a number of Televue scopes, including a TV85 which I loved. It is a beautifully engineered 'nugget', built like a tank and something which will last several lifetimes if cared for properly. Optically I found it very good, though I would say it is a little behind the Tak in terms of sharpness, scatter and contrast. The additional 15mm aperture also has a significant impact at these sizes in terms of the available resolution. I found clear differences in every step up from a 66mm William Optics scope, through the TV76 then TV85.

I do indeed love this scope and plan to use it exclusively for at least a year, incrementally (experimentally) upgrading everything peripheral to make sure I'm getting all there is to be had out of it; we'll see whether my nagging greed for more aperture / focal length subsides.

It's hard to imagine anything bigger that is just as grab-and-go. It's even harder to imagine me not ever getting a 102mm, a 120mm or a 150mm. It's hardest to imagine me not keeping the TV85 for several lifetimes.

1 hour ago, Stu said:

I do think you would benefit from getting away to a more stable site. As John says, light pollution is not really a big issue for planetary observing, but local and high level seeing conditions are critical to being able to catch the fine detail. Getting away from chimneys and heating plumes, plus keeping an eye on the Jetstream forecast can make a huge difference.

Soon!

1 hour ago, Stu said:

From experience with the TV85, I know that I found benefit in using eyepieces down to around 3.5mm under the right conditions. I used a number of different ones including a Nag Zoom, 3.5mm Type 6 Nag, 3.5mm Delos and 3.7mm Ethos SX. In terms of focal length, I found the Ethos to be about the most consistent as an optimum maximum under good conditions (or the nag zoom at the same f/l but the quality is not quite to Ethos standard). I did not particularly get on with the Ethos eye relief or field of view though and sold it. The 3.5mm eyepieces were lovely but just a tad too short to be optimum much of the time.

This mirrors my own experiences; I also have and have used the Nag 3-6 Zoom and 3.5mm Type 6 Nag. The Zoom is irresistibly useful at times, like a "second focuser" even though, as you say, it's not on par with an Ethos. Somewhere between the 5mm and 4mm stops is usually the highest magnification before the returns diminish; the 3.5mm T6, while clearly very good, confirms this and makes me suspect that a 3.7mm Ethos may well be an over-investment for this setup.

On the other hand, and these are possibly factors down to personal taste, I've yet to be bothered by the eye relief of an Ethos and the field of view is - for me, using a manual alt/az mount - fast becoming essential for maximum enjoyment.

1 hour ago, Stu said:

Your comments about the stability of image at varying magnification are very accurate and interesting. The same applies to different aperture sizes. I was observing using both 4" and 8" scopes the other day, and the seeing was quite variable. The 4" frac was giving pretty stable images, cutting through the seeing reasonably well, but the 8" was far more variable. When the seeing was at its best, it showed more detail than the frac, but at its worse it was far blurrier, which made the frac more enjoyable to observe with.

For my part - not having caught as much as a single photon via a mirror other than one mounted in a diagonal, and even having provisionally replaced that one with a prism - I'm quite sure I've become a lifetime addict with regard to the sharpness and "snap" a refractor provides. I'm sure you've read, as I have, elsewhere on SGL about one of us (one with a lot more experience than me) deploring the view of "Newtonian stars"; while I'm quite open to using a reflector and feel I should at least own and use one for a while, sometime in the future, it's hard to imagine me putting up with an experience of that description.

 

Thanks for your comments Stu, they are most encouraging!

Mike

[Stu]

Good stuff Mike, I like your approach ?

Just to clarify a few points. I have no issue with the normal ethos field of view, it is lovely! I struggled with the 110 degree afov of the 3.7 SX for a couple of reasons. Firstly, for some bizarre, personal reason I need to see the field stop to be happy that I'm not missing anything. Stupid I know but that's life. In order to do this, I found myself pushing my eye further into the heavily dished exit lens, and often found myself viewing my eyelashes more than the target! As you say, it's a purely personal thing, the views themselves were exquisite! Being able to fit the full moon into the fov at x162 was pretty spectacular!

I would reserve judgement on maximum mag until you have used the scope under stable seeing conditions. I agree that 3mm is too much generally, but sub 4mm can definitely show some more, even if it is just by increasing image scale without adding further detail.

I've used many high quality small refractors and find that using exit pupils down to 0.5mm is often useful/required to get the most out of them for high power work. The optics are good enough, the limiting factors are eyes and conditions. Even below this at 0.4mm it can be useful on double stars or the moon. My problem ends up being visibility of floaters in my eyes which get significant at these levels.

Have fun with the scope Mike, I look forward to reading more about your experiences. Oh, and by the way, get yourself a Herschel Wedge and (making sure you know what you are doing!) look at the sun with it in the TV85. This combo works really well ??

[Stu]

Oops, I've derailed my own thread! Apologies.

Back to Jupiter, we can pick up the TV85 elsewhere ??

[iPeace]

13 minutes ago, Stu said:

Oops, I've derailed my own thread! Apologies.

Back to Jupiter, we can pick up the TV85 elsewhere ??

My fault Stu, I know by now how contagious this scope can be

[niallk]

Super post Stu   - after a (rare) night of decent seeing, I too often look for postings from the imagers to compare to what I've seen.

I guess that at different times (because Jupiter is so changeable), I've seen all the labelled banding structures in my 250px with binoveiwer @220x.

It's been a while since I've seen a dark ruddy brown coloured barge, but have done several times in the past.  There have been some great festoons recently - blueish grey to my eyes.  I've really enjoyed Jupiter over the last month, and love catching transits.

I see a sharper version of the pic Jetstream posted on a good night of late, with a slightly darker brown hue to the banding in my 15" at 280x in a 7mm Nagler - I've read they may give 'coffee tones'...

What I find is that my 250px with binoveiwer and 15" cyclops give very similar views: I typically can view sooner with the quicker cooling 250px, and tend to view at 280x in the 15" - which is just much nicer from a balance and smooth movement perspective - important when patiently waiting for those really crisp moments, when some finer details in the turbulent regions flicker into view briefly. I need to get collimation spot on in the 15" though - it seems more sensitive to this (f/4.7 vs f/4.48 ...?)

I'm yet to clearly catch a white oval this year. The GRS is an immediately noticeable salmon pink.  I've read reports from people in places like Florida going to 1000x and seeing whorls within the GRS - only a dream for me. I've never discerned detail on the moons either! I did have one morning years ago on Saturn when there was just no discernable atmospheric blur - the seeing must have been exceptionally good. What I'd give to catch those conditions again! Which is part of the fun: just keep on trying and you might get really lucky - a bit like going fishing

[Size9Hex]

What a outstanding post. Nice one Stu! 

I wish I had more time to do it justice. I'll paste a quick screenshot below, and if you put your eyeball a close few inches from the screen, I think it's a reasonable approximation of the view in the Skywatcher 250px on a good night with patience. 180x is my main mag, but 250x when seeing allows. A few things that spring to mind compared to the photo.

• The Great Red Spot is seen to be darker in the south than the north.
• White spots in the southern temperate belt in the photo have never been seen.
• North polar region does indeed look bit marbled (seen 1 or 2 nights in 10 maybe), but I'd struggle to say anything specific about it. It's just a subtle texture.
• The moons intrigue me too. When they are close together, I feel that Ganymede and Callsito can be identified as being larger than Io/Europa. Io looks a muddy ochre yellow compared to Ganymede which seems more of a grey-brown colour, but the colour is extremely dependent on where you catch them (transit or open sky). When Europa emerged from eclipse (only seen once and I'm keen to check this again one day), it looked briefly "wrong" for 30 seconds or so - tall and thin basically, but not with any specific shape exactly.

 

Edit: I definitely did paste a screenshot here! Let me see if I can figure it out... 

[Size9Hex]

Here we go... hopefully...

[niallk]

Have had the scope out cooling for 2hrs tonight in case the cloud bands passed a little to the north of the southern coast of Ireland, and have had to use the hair dryer once already on the secondary - but WOW! Jupiter is looking great tonight @ 205x (15" f/4.5 w/Paracorr + 2.5xPM + Panoptic 24mm).  There's a star (HD95848) that makes it look like there are 5 moons at first glance!  I reckon I can see 3 white ovals in the South Temperate Zone region - will have to compare against someone's image tomorrow There are several festoons, and just waiting for the GRS to continue to rotate across the disc. Tantalising detail in both the NEB and SEB; GRS showing a strong reddish salmon colour.  So glad I took a chance and threw the scope out!!!

Good also with the 7T6 @280x, but not so good at 380x (PM'ed 13T6). Light cloud obscuring from time to time - and dew threatens to end the fun!