Telescope viewing

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Telescope viewing

Postby faultycelery34 » Mon Jul 02, 2018 9:25 am

So I've recently bought a telescope and I was viewing Jupiter last and I could see it with 4 of its moon. But Jupiter itself just looked like a ball of light (a bit like the photo attacked below). I use a Nova 114mm x 500mm reflector telescope and a 10mm lens with a 2X barlow. Was just wondering if there is any way I can better my view of Jupiter and maybe start seeing some detail e.g the bands. Thanks
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Re: Telescope viewing

Postby Aratus » Mon Jul 02, 2018 9:28 pm

If you are in the southern hemisphere then at the moment low altitude will not be a problem! The seeing conditions might still not be good. Wobbly images are not helpful. Try again on a better night. Your telescope has a fairly low focal length so high magnifications are going to be difficult to achieve. Getting a 3x barlow with your 10mm eyepiece will get more magnification out of your telescope which with good conditions will help resolve a band or two on Jupiter.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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Re: Telescope viewing

Postby faultycelery34 » Tue Jul 03, 2018 10:35 am

Aratus wrote:If you are in the southern hemisphere then at the moment low altitude will not be a problem! The seeing conditions might still not be good. Wobbly images are not helpful. Try again on a better night. Your telescope has a fairly low focal length so high magnifications are going to be difficult to achieve. Getting a 3x barlow with your 10mm eyepiece will get more magnification out of your telescope which with good conditions will help resolve a band or two on Jupiter.


If I used a 4mm lens and a 2X barlow would that help?
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Re: Telescope viewing

Postby Aratus » Tue Jul 03, 2018 5:06 pm

A couple of problems with your suggestion.

As it is - 500/10X2 = mag 100
3xbarlow - 500/10x3 = mag 150
4mm EP - 500/4x2 = mag 250

Now you have in effect a 4.5 inch telescope. 40x per inch is a maximum for most seeing conditions. 4 .5 x 40 is 180x, so straight away you can see that using a 4mm EP is going to mostly give a pretty dim image.

The other problem is that using a small focal length EP would also reduce your eye relief. If you are under 40, that might not be a problem, but the older you are the harder it is to cope with the image produced by a small focal length eyepiece. Finding the object when you put your eye to the EP becomes more difficult with smaller magnitude EPs. As you get older the eye gets worse at finding the image. You could try an 8mm EP for mag 125x Even my ancient eyes can cope with an 8mm! I still think the 3x barlow is the better solution for 150x and good eye relief.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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Re: Telescope viewing

Postby faultycelery34 » Tue Jul 03, 2018 8:51 pm

Aratus wrote:A couple of problems with your suggestion.

As it is - 500/10X2 = mag 100
3xbarlow - 500/10x3 = mag 150
4mm EP - 500/4x2 = mag 250

Now you have in effect a 4.5 inch telescope. 40x per inch is a maximum for most seeing conditions. 4 .5 x 40 is 180x, so straight away you can see that using a 4mm EP is going to mostly give a pretty dim image.

The other problem is that using a small focal length EP would also reduce your eye relief. If you are under 40, that might not be a problem, but the older you are the harder it is to cope with the image produced by a small focal length eyepiece. Finding the object when you put your eye to the EP becomes more difficult with smaller magnitude EPs. As you get older the eye gets worse at finding the image. You could try an 8mm EP for mag 125x Even my ancient eyes can cope with an 8mm! I still think the 3x barlow is the better solution for 150x and good eye relief.


Great, thank you!
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Re: Telescope viewing

Postby The Man with the Corrugated Iron Roof » Mon Jul 09, 2018 5:02 pm

I find a moon filter works well on Jupiter and Venus because they are so bright. Failing that, sunglasses will help to reduce the glare. My photos of Jupiter's moons look just like yours. I sometimes cheat by taking a photo of Jupiter with a shorter exposure then combing the two photos digitally.
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