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SpaceDawg

So I've Not Been to Jupiter But...

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...is it blurry up close?

I had my scope out for the second time tonight (twice in one week, eee!), still at the lower point of the steep learning curve but I had my astronomical climbing gear to hand (is this metaphor getting out of hand?) Anyway, just before 10pm Jupiter finally rose above the horizon (well, my neighbours house) and I got my first look at it (which was handy as it was something reliable with which I could properly align my finderscope, after looking at Pleiades through it all night but god-knows-what through the actual scope!)

Using both the 2x barlow and 10mm eyepiece that came with the scope, Jupiter looked quite blurry. Removing the barlow made it look better but I assume this is simply because the blur wasn't magnified. I spent ages tweaking the focus but I couldn't get it very sharp.

My question is where does the problem lie? Is it with the eyepiece, the motor (had that going for the first time tonight), the idiot running the show or something else I haven't thought of? :grin:

The scope is a 200p on a HEQ5 (must post more so I can just put that in my sig!)

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You sure it wasn't just atmospheric turbulence? If it isn't turbulence make sure it's collimated properly.

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Seeing conditions aren't great tonight. Anything over x100 magnification was very blurry for me. Was sharper at c x50 for me.

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I don't know what the transparancy was like for you but down here there was a lot of moisture in the air the sky was very red/brown that will affect views especially at high power

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Definitely the seeing tonight, lots of ppl complaining about it tonight. Seems like there's a lot of moisture in the air. Roll on the frosty nights!

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at 10pm it's likely to be atmosphere. it's improved here substantially since 10pm and will continue to do so as the night goes on if the weather plays ball.

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Also, viewing over rooftops will completely destroy the image. So much heat escapes from the roof tiles, it'l be like trying to view from the bottom of a swimming pool.

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Jupiter at that time its too low, been viewing it from about 12am until now (1.30am) and it looks fantastic, had a look earlier and it was just a fuzzy blob like you said. pushed the mag up to around 240x, could have gone a bit further. Oldham is quite high up so maybe the seeing here was a lot better than other places.

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Just to add more food for thought, as a general rule of thumb the brightness of an object will decline as you up the magnification. If I up the mag twofold, say, I'm reducing the image brightness by a factor of four. If I keep on doing this eventually details just disappear. On the other hand, increasing the mag does make detail more apparent, so, as you can appreciate, we're now at a trade-off: will increasing magnification gain more detail even though I'm making the object fainter?

I've found that playing around with this trade-off - dependent on the evening's seeing (I've found that LP doesn't really affect planets) - does make a difference. Even as little as 1mm increase or decrease in the mag - about 10% to 15% difference of magnification - can be quite surprising. You'll probably find that on a decent night your sweet spot is around 140x to 160x on viewing Jupiter and you will probably only be able to push 200x on the most excellent of excellent nights. With this is mind, I think barlowing your 10mm on an f/5 was a tad optimistic.

You've got a wonderful 8" telescope reaching out across the universe some 675,000,000 kilometers and I'm sure - on another better evening - 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. From time to time, if you want to enhance that colour of the giant maybe a light blue filter will work nicely, or a Wratten 11 or 12.

If you can, try to sit with Jupiter for a peaceful twenty minutes or so on your next observation session and I'm certain they'll be moments of great clarity and seeing. I've been following Jupiter since late July and every week it gets just that little bit better, the moons are getting brighter and more detail can be tweaked from the planet. Stay with it and as the weeks go by you will notice quite a difference.

Edited by Qualia
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Thanks for all of the replies. Being very new to all of this (less than a week!) I just thought a clear night was all I needed. Didn't think about moisture, atmosphere and the heat from the neighbour's house (they also have a room at the back with no curtains and they leave the light on all night...damn them!) I have a young daughter who doesn't tend to sleep very well through the night so me staying up until all hours isn't feasible at the moment (unfortunately). I'd taken the scope outside as soon as it went dark and spent most of the time outside. As a result I was pretty cold by the time I decided to call it a night. Perhaps in the future I'll go out later (and buy some thick socks!)

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I've got a Storm 60 with a x3 Barlow, Dawg, and Jupiter is blurry and out of focus. I think I need to step down to a x2 like you have, but I'd say definitely wait until your planet is well above the horizon. It's worth getting a crick in the neck for. :)

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