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grs struggle


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Hi all,

I have a quick question for you folks. I have been observing Jupiter for the last couple of nights through my skywatcher 200p. I can just about make out 3 darker cloud bands, but was wondering about how easy the great red spot would be to see. The cloud bands I can see are quite feint, and I understand that the grs has been quite feint also in recent years. The reason I ask is that I have just read a post on here where someone mentioned they saw the grs and a couple of smaller trailing spots through a four inch refractor! I think i would struggle to see this at the moment. Would it be because...

Light pollution- I live in a fairly light polluted area, but certainly not the worst.

Bad seeing- Am I just being unlucky with bad seeing

Eyepieces- I am still using the stock 10mm and 25mm eyepieces and also a 6mm plossl from celestron (very basic model)

Any input on this subject would be most welcome

P.s. collimation is good on my scope star test revealed concentric circles

Thanks

Ian

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you may have just been unlucky with the side presented to you. the GRS rotates along with the planet and may not have been on view at the times you have observed. I would say that it's pretty obvious when it's there.

this site http://www.skyandtelescope.com/skytel/beyondthepage/Great-Red-Spot-Transit-Table-2012-2013-159437655.html gives transit times for the current year or so http://www.skyandtelescope.com/skytel/beyondthepage/Great-Red-Spot-Transit-Table-2012-2013-159437655.html

I think I am right in saying that Universal time is the same as GMT?

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I've seen the GRS with my 4" and 4.7" ED refractors over the past few nights. It resides in the southern side of the south equatorial belt so in Jupiters southern hemisphere. The most distinctive feature is the "hollow" that the spot sits in on the southern side of SEB, which seems to have a pale rim to it. The spot itself appears pale grey really, maybe just a touch of pink now and then, and is "eye" shaped. Currently there is a dark plume or partial belt that appears to start on the southern side of the spot and trails back behind the spot, so to speak. There have sometimes been pale eddies following the spot across the disk.

I find the most effective magnifications to be 165x - 190x with my 4" refractor and 180x - 225x with the 4.7". With the exception of the main 3-4 belts, these details don't usually jump out at you. I find they become more obvious after 30 minutes or so observing the planet and your eye gets "trained" to pick out the details. Seeing conditions cause the finer detail to come and go so the more time you spend looking, the more times you catch those moments when the scope gives its best views.

Hope that helps - your scope is fine and completely capable. Just spend as much time observing the planet as you can. I don't use any filters by the way. The 6mm eyepiece should do the trick if you keep at it.

I try to resist checking to see where the spot is initially to try and ensure that I observe what is, or isn't, there rather than what I'd like to be there, if you see what I mean :smiley:

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I totally agree with John's summary although I do use a filter - Baader Neodymium as I believe this brings out a little more contrast. I have seen the GRS and lots of other detail recently with my 6" f11 newt and at magnifications between 100-250x. you just have to be lucky with timing. in your scope it will appear at about the 2 o'clock position and work its way left across the disk.

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I find they become more obvious after 30 minutes or so observing the planet and your eye gets "trained" to pick out the details. Seeing conditions cause the finer detail to come and go so the more time you spend looking, the more times you catch those moments when the scope gives its best views.

I agree with everyone's advice but this bit is the advice I got given once and following it has helped my observing no end. Patience at the eyepiece pays :)

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I agree with Moonshane regarding the neodymium filter, in that for me, it does make a slight improvement on contrast and so teases the detail out just a bit (no silver bullet I'm afraid) but patience here is the key - difficult with the lack of clear sky I know! :grin:

James

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+1 for the patience bit - My best moments with Jupiter have been when trying to make a sketch of what I see. I find it forces you to spend a lot longer at the eyepiece and to try and tease out the details. Your eye definitely "tunes in" the longer you spend on it. The other benefit of spending a lot of time on it is that you'll get more of those occasional moments when the atmospheric turbulence subsides for a couple of seconds and you suddenly get a much clearer glimpse.

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Instead of looking directly at Jupiter, if you view with your right eye, look slightly to the right of the planet, if you view with your left eye , look just slightly to the left , the edges of your pupil will pick up more detail then if you looked directly at Jupiter

Have fun

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Your 6mm should be enough to see it if its facing you. I just had a quick look earlier with just a 8mn vixen. I could see 3 solid band and 2 thinner ones, GRS, some darker shaded clouds like the barge but not exactly sure if it was, some polar detail and some turbulent cloud around the GRS. Mine had been left outside since about 8pm (I went out about 22:30) so it had ages to cool.

Detail comes and goes. Few seconds it'll look blurry then all of a sudden all this detail comes out of nowhere.

I live about 2 miles outside centre of Liverpool so get a lot of LP. Just practice mate and have a lot of patience.

Enjoy.

Tom.

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I forgot to say. With the 200p and the 8mm EP that gives roughly 125x on its own with no Barlow. I tried a Barlow but just blurred out completely.

I've been able to get 200x with a lot of detail once. Other times they've just blurred it. All depends on what the atmosphere is like. Keep with it!

Tom.

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