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focusing on Jupiter


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I am fairly new to this hobby and I am having difficulty getting Jupiter in clear focus. I have a Skywatcher 130 explorer and several lenses including a 25 mm plossl and a 5 mm BST starguider plus a 2x Barlow. The problem is that I can't see any detail I.e. the different coloured bands which I would to expect to see. I can see 4 of the moons of Jupiter. I have also tried an IR filter and a moon glow filter and a combination of the two.

I have also converted a lifecam webcam and again I can see the moons but Jupiter is just a blob. Do I need to collinmate the scope or is there something else.

Any help would be appreciated

Jake

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With my celestron 130, Jupiter is a large disc, with some detail on a night with very good seeing, but you will never see it the same as in the books. If I use a 9.8mm and 2x barlow, on a very good night I can se bands if I relax my eyes and allow them to 'see' for a while - but I found it it takes quite a bit of practice

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Hello Jake. A good tip for focusing on Jupiter is to at first focus on the moons, once they are the smallest points of light Jupiter should also be in focus. You will not see much in the way of colour on Jupiter with a 130mm aperture. A 5mm eyepiece should easily show you the two main cloud belts, to check your collimation defocus Jupiter and the black dot in the image should be central, if not then collimation is required. If you can see the moons with your lifecam then Jupiter will be over exposed and not show any detail. You need to up the magnification or reduce the exposure, failing that try a ND filter.  :smiley:

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I find less is more with Jupiter, through my 10"SCT it is a blurry blob but through an 80mm f/9 refractor I can see the bands.

Dave

Is that a focal length issue rather than a aperture one. I guess the SCT will have a much higher magnification, thus requiring better seeing - no?

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According to the Skywatcher blurb the 130 Explorer will give "memorable views of the bright planets" not sure what that means, you can remember that you can't see any bands, is that a memorable view ? :)

Dave

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Jake,

When it comes to viewing Jupiter, good seeing conditions are very important and assuming your collimation is also spot on you'll find that on average, Jupiter doesn't really need much more than 100x to begin observing some interesting detail. Of course, depending on the night's seeing you can up this magnification .

You've got a lovely scope, but recall, it is one typically used for wide views, rich star field observing. Obviously. there's no reason why you can't do planetary work with it but you may on occassion find you need quite high focal length eyepieces or the Barlow to gain the necessary magnification. If possible, make sure your collimation is spot on and start out with around 100x and see how Jupiter appears in your 5" f5 reaching out across the universe some 675,000,000 kilometers. If the stars are twinkling naked eye and you're viewing a blurry mess of Jupiter, then spend the night on clusters and star fields and come back another night.

Both my 3" and 4" frac can make out the north and south equatorial belts, great red spot, the equatorial band and the north and south polar regions. If you stick with him, gradually, after 15 minutes or so, Jupiter reveals even more subtler markings especially in the north and south temperate belts and larger markings in the north and south tropical zones. So you really shouldn't have too much of a problem.

Try to view Jupiter as close to the zenith or celestial meridian as possible and I'm sure with a little practice you will be able to see the Great Red Spot, those delicate reddish-brown belts, a darker, greyer hue to the Polar regions, and so on. You'll be able to trace the movement of the Jovian moons and observe their play of shadows over Jupiter in times of transit or of their eclipses by Jupiter's own shadow.

If you can, try to sit with Jupiter for a peaceful twenty or thirty minutes or so on your next observation session, ask yourself questions about what you are seeing, perhaps make a little sketch which also helps the eye to see more.

Good luck and let us know how you get along.

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Your scope’s primary mirror will produce its sharpest images when your eyepiece is aligned with the mirror's focal plane. That's why collimation is so important; if it isn't well aligned the image may suffer coma. In effect, you end up seeing less detail and in light of the orginal enquiry, Jupiter’s belts may vanish.

An ND filter blocks a given degree of brightness from objects. The only time I've ever had occassion to use one is the ND 3.0 filter in my Herschel Wedge.

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i also have just got the explorer 130m and saw jupiter for the first time last night (have obviously seen it before but didn't realise it was jupiter but a bright star)

i too couldn't  get a very clear view using my BST 8mm starguider and was a bit disappointed to be honest.

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Been out tonight myself looking at Jupiter through a 6mm wo and a 15mm vixen, on my 200p Dob, I agree with the sentiment that sometimes less is more as the 15mm ep gave me a better overall view where the 6mm takes more time to relax your eye as other's have said.

Having said that, I have very recently collimated the Dob and I could clearly see some good banding and more once I relaxed my eye / focus a bit.

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Newb with a 100p here but similar to others I have found high magnification unhelpful. Using a 9mm (c45X in this scope) without Barlow and some patience I have seen the dark bands

learn a lot about patient viewing on Jupiter; get the moons as dots, sit a while (with both eyes open) and Jupiter reveals itself - quite magical   :grin:

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Even on a 200P it takes time and patience, and for me, still  hoping for better weather, as I have new EPs to test,  the weather is constantly pants?

I have had one perfect moment with Jupiter, and the Moon transit shadow was clearly defined. An image not forgotten.

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