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Paul G. Abel

Jupiter; GRS and Oval BA

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Greetings all!

Here's a couple of drawings of Jupiter, one showing the GRS and Oval BA, the other drawn much later after the spots had rotated off the disk. There is much activity on Jupiter now, the NEB is broader and darker than it was, similarly the NTropZ is a darker almost salmon colour. Looking forward to some long nights with the planet around opposition!

Best wishes,

-Paul.

Jupiter_2012_10_13_23-10_Visual_PAbel_zps960595a9.jpg

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Gets a thumbs up from me! My fingers get so cold out observing, I don't think I could hold a pencil, never mind draw something!

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Absolutely superb Paul :smiley:

Shows what detail can be seen when time is spent really studying the planet. I notice the scope is a 203mm newtonian - can I ask which brand it is ?.

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I think that's a stunning result for an 8" newt.

The blue-edged features up against the NEB fascinate me. They look like the image has become ink-stained after it was made. I thought at first it must be a fault in my images, but they show up in all the ones I've seen this year and look very similar.

James

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Wow thats a great observation of Jupiter Paul and thanks for posting. :)

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Looking good there Paul. There's some excellent detail up around the GRS at the mo. Quite a treat...when the sky is clear.

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Absolutely superb Paul :smiley:

Shows what detail can be seen when time is spent really studying the planet. I notice the scope is a 203mm newtonian - can I ask which brand it is ?.

It's a skywatcher. It's permanently mounted in my observatory.

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Thanks all! @James, they're called festoons, and they have been well documented by Jupiter observers from at least the 1800s. Like everything else on Jupiter, there is some variability in their frequency and contrast since the EZ seems to undergo periods when it is not as active as at other times. A red W#25A filter helps to enhance them visually.

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I'd like to observe Jupiter better, so I understand the filters mentioned above, and the magnifications. May I ask your eyepiece of choice? Ortho? Plossl? Wide Angle?

Thanks!

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I'd like to observe Jupiter better, so I understand the filters mentioned above, and the magnifications. May I ask your eyepiece of choice? Ortho? Plossl? Wide Angle?

Thanks!

To be honest, it really doesn't matter too much about the make of the eyepiece, so long as the glass is a reasonable make. I have a mixture of wide angle and some standard plossl eyepieces. You will no doubt here advice about choosing the most expensive eyepieces, but I would ignore that personally, none of mine are particularly expensive. The main tool you need is time. When most people have a go at visual observing, they have a quick five minute look and declair that all they can see is a white disk with one or two bands on it. Well yes, that is the first impression, but you have to work beyond that. I spend 15-20 minutes looking before I even make a drawing. You have to train your visual system to see what's there, get your eyes to respond to the faint delicate markings and the subtle colours which are present on the Jovian disk. Visual observing is like exercising, the more you do it the better you get.

As for magnification, the answer is the right magnification is the one which suits the seeing- your telescope may allow powers of x400, but this is quite pointless if the seeing is poor, all you will see is a steam pudding. So always make sure the disk of Jupiter is sharp and as focused as possible. On an average night, Jupiter will tolerate anything from x160 to x250. Good nights I use x300 or more, on truly excellent nights I have used x400 and x500 for some overwhelming views.

Hope this helps,

Paul

Edited by Paul G. Abel
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If you start to see canals though, it's time for a break :)

James

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Levity aside I think Paul is making a point here that perhaps I'd not really internalised (I don't currently spend a huge amount of time actually looking at planets, I admit). The impression I have is that a fair bit of the cost of more expensive eyepieces is paying for the large field of view and the quality of the image towards the edges (though clearly that's not all you're paying for). If you have a scope on a tracking mount that does a good job of keeping a planet (maybe even globs and other small DSOs) in the centre of the field of view then the off-centre performance of the eyepiece perhaps isn't so much of a concern. I imagine many people would get as much out of a BGO (or something even cheaper) as an Ethos in that situation.

If you're using a large manual dob on the other hand, stick a 6mm BGO in it and you'll quite possibly spend more time playing "chase the planet" than you will having it clear and steady in the eyepiece. In that situation a nice wide well-corrected view is a real benefit.

James

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Excellent drawings Paul, I agree with your recommendations especially tim. Spending time at the eyepiece is the secret to planetary observing but may I add one more recommendation? An essential for me with my creaky back, a good observing chair so you are comfortable at the eyepiece.

I have fond memories of observing Saturn back at SGL7 for over an hour (approx 0100 to 0200) sat on my Lidl ironing chair just drinking in the views through my 127 refractor with different eyepeieces and filters, I have never seen so much on that planet before.

I am now using the same technique with Jupiter and its amasing what can be seen.

philj

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..... The main tool you need is time. When most people have a go at visual observing, they have a quick five minute look and declair that all they can see is a white disk with one or two bands on it. Well yes, that is the first impression, but you have to work beyond that. I spend 15-20 minutes looking before I even make a drawing. You have to train your visual system to see what's there, get your eyes to respond to the faint delicate markings and the subtle colours which are present on the Jovian disk. Visual observing is like exercising, the more you do it the better you get.

As for magnification, the answer is the right magnification is the one which suits the seeing- your telescope may allow powers of x400, but this is quite pointless if the seeing is poor, all you will see is a steam pudding. So always make sure the disk of Jupiter is sharp and as focused as possible. On an average night, Jupiter will tolerate anything from x160 to x250. Good nights I use x300 or more, on truly excellent nights I have used x400 and x500 for some overwhelming views.

Hope this helps,

Paul

This is great advice Paul. We ought to make it a "sticky" on planetary observing technique :smiley:

I also find that, apart from a few exceptional nights, the seeing conditions just give you brief glimpses of the true resolution your scope can achieve. The longer you spend observing an object, the more of those glimpses you get and your eye and brain seem to string them together (almost like the a visual equivalent of stacking images !) so in time you seem to perceive more overall detail.

It's subtle stuff but so rewarding when it comes together :smiley:

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Gets a thumbs up from me! My fingers get so cold out observing, I don't think I could hold a pencil, never mind draw something!

Had to laugh at this as im exactly the same, in summer i was sketching every DSOs while at the EP. Come winter, its hand in pockets time.

They are brilliant drawings, really brought out the detail.

Edited by Matt Scunthorpe

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