How big, in my field of view, will Jupiter be looking through this telescope?

Question

http://www.telescope.com/control/product/~category_id=reflectors/~pcategory=telescopes/~product_id=09184

Answer 1

A 10-inch Newtonian will show Jupiter nicely, but it's difficult to describe "how big" it will appear. To my eyes, I think of it as a small image, but well-detailed. If you crank the power up a bit, it will get bigger, of course. The image may degrade slightly, and the other drawback is that it will move out of the FOV more quickly.

Answer 2

For any given telescope, magnification will depend a lot on what size eyepiece you use. The smaller the diameter, the greater the magnification.

I'm looking up your link but it is slow coming up. I'll get back to you when I see it.

Hey, nice telescope. When I first saw the picture of it, I never would have thought it was a ten-inch. So at 1200 it's about an f-4.7. With a 20 mm eyepiece, you will get a clear, bright view of Jupiter. You will be able to resolve its diameter and easily see the four Galilean moons. If you go to a 7mm eyepiece, it will appear about the size of a penny at about 6 to 10 feet. It won't be as bright, which is actually a good thing, because now you will be able to see some of the cloud bands.

It will never look like the pictures, so don't be disappointed. Just the fact that you are looking at it with your own eyes will be rewarding enough.

Quite right, Bobby, I checked my math on that f number and saw I had made a mistake. So Jansen, fast scope, good light-gatherer, like he said. But you will still be able to get nice views of Saturn, Jupiter, Mars, and Venus, with that large aperture. This scope is made more for deep sky and I would recommend getting something like a 50mm Plossl eyepiece, so that you can see larger nebulous objects and open clusters all in one field.

Answer 3

This scope comes with two eyepieces, which will give you magnifications of 48x and 120x. These are mainly for general viewing. 120x will show you a fairly small image of Jupiter, about three times the diameter of the Moon as seen with the naked eye. This will show you the four Galilean moons of Jupiter, the two or three main dark belts on the planet, and possibly the Great Red Spot.

I find, with a scope this size, that I get my best views of Jupiter with a magnification between 200x and 250x. For this you will need an eyepiece with a focal length of about 5 to 6 mm. The problem with inexpensive eyepieces in this focal length is that they have very short eye relief, meaning that you need to put your eye very close to them to see anything. A better solution is to buy something called a Barlow lens. This is a lens which, when inserted between the focuser and an eyepiece, effectively doubles the magnification of the eyepiece. A good example is this one:
http://www.telescope.com/control/product/~category_id=barlows/~pcategory=accessories/~product_id=05121

A Barlow lens can be used with any eyepiece, and essentially doubles the number of magnifications you have available. So, with a Barlow, you will have 48x, 96x, 120x, and 240x. I wouldn't worry about getting this right away, as you will have plenty to occupy yourself with, with the two eyepieces supplied with your telescope. Besides, Jupiter is now behind the Sun for the next 6 months or so.

Anyway, with 240x in this scope, you will be able to see a large amount of fine detail on Jupiter, in particular the beautiful festoons along the southern edge of the North Equatorial Belt. At first, Jupiter will probably look tiny to you, but the image is very finely detailed and, as your eye becomes trained, you will see more and more.

Currently Mars is well placed, and with a 10" scope at 240x you will be able to see the North Polar Hood, soon to condense into the North Polar Cap, and the dark highlands visible against the orange of the deserts. At 240x, Mars will appear about twice as big as the Moon seen with the naked eye.

Answer 4

That's a great scope. Depending on the eyepiece you use, you should easily see some pretty good detail in the cloud bands that surround the planet. With a 1200 mm focal length, you could get 200X with a good 6 mm eyepiece. That should easily resolve the planet Jupiter as a disc that appears about the size of your fingernail at arm's length.

Don't limit yourself to Jupiter - with this scope you can easily see galaxies that are 40 million light years away. Just gotta find 'em. Enjoy.

Added:

Careful - I wouldn't go much beyond 200X - you will not get a good clear image. Anything beyond 400X I would describe as unuseable.

Answer 5

Because this telescope is f/4.7, it means it is a "fast" telescope; one that will give you a wide- field of view.
Planetary observations are possible, but to really crank up the size of Jupiter in your field- of- view, you'll need to REALLY bump up the magnification.
For higher power, high- resolution views of the planets, a somewhat 'slower' telescope (higher f/ number) would be more appropriate.
Slower telescopes offer a narrower field- of- view, thus the ability to magnify more with the same eyepiece than a wide- field scope.
Either way, the size of a target in your field is dependent upon the eyepiece you are using.
I have an f/10 SCT, and one night, when 'seeing' was almost perfect, I managed to target Sturn at just over 700X, and it almost filled my field- of- view!
It was gorgeous!
I hope this helped!