Viewing Jupiter.

[Tremolo]

I saw Jupiter on Wednesday night and it was fantastic as I could also see what I assume were Callisto, Ganymede, Io and Europa. Unfortunately I couldn't see any details of Jupiter at all, it just appeared as a slightly large star. My current set up is an Orion Observer, 60mm refractor with 25mm and 10mm lenses. The conditions weren't perfect, and I'm quite new to this. I'm just wondering if I'll ever be able to make out details ( even a single cloud band, anything ) with this set up without higher magnification. I've been looking at 1.5 x barlow lenses and in another topic on this forum I've been told the best thing to do is to get another lens?

[John]

What focal length is your 60mm refractor ?. When I used to use one (which had a focal length of 800mm) I found that a 6mm eyepiece (133x) was the absoloute max that I could use in really good viewing conditions. With Jupiter pretty low down you would probably find 100x a more useable power - to find out what eyepiece you need to get that divide the focal length of your scope by 100 - the result is the focal length in mm of the eyepiece you need eg: 800mm / 100 = 8mm.

The nearest you can get to that in a reasonable eyepiece design is a 7.5mm plossl:

Skywatcher - Skywatcher SP Plossl eyepieces

John

[old_eyes]

I first looked at Jupiter with a 6" Celestron SCT and a 25mm eyepiece - my first astronomical object with my first telescope. Isn't it a blast?!

At first I saw just a small bright disk, but after waiting for a while and just letting my eye rest on the target, a couple of darker bands just sprang into view. Once I had got them, they remained clearly visible. A bit like suddenly 'seeing' an optical illusion. Other times I have looked at Jupiter it was the same, so my learning on seeing the bands clearly is:

1. Be patient and allow your eyes to dark adapt. I saw the bands much better later in a session.

2. Relax and let it come. It seems if you 'look' too hard the eye doesn't see the detail.

Keep trying

old_eyes

[pvaz]

On the other thread you asked for a barlow so I advised on what your ware looking for. Now, instead of advising, I'll tell what I would do in your situation:

Your scope FL is 900mm and the max potential magnification is 140x. To get that magnification you need a 6.5mm EP. The cheapest well rated eyepieces for planetary are the University Optics Orthoscopics (sold as CircleT in the UK).

They don't have a 6.5mm, but they have a 6 and a 7mm. The 6mm will give you 150x, and the 7mm will give you 128x. At 120x on my scope the 2 equatorial bands are perfectly visible on a good night so any of this mags should be fine. If you want to be safe buy the 7mm and stay bellow the max mag of your scope or you can go for the 6mm witch is only 10x over the recommended limit.

You can buy them here at 59.95 USD a piece:

Eyepieces - 1 1/4" Oculars from University Optics

[brianb]

I'm just wondering if I'll ever be able to make out details ( even a single cloud band, anything ) with this set up without higher magnification.

The main problem with Jupiter at the moment is that it's so poorly placed. More magnification is NOT the solution, in fact you're very probably using TOO MUCH, x25 to x30 should show the main belts and is far better suited to your small aperture scope.

[pvaz]

Brian, I disagree a bit. It is low! But you are assuming Tremolo is at your latitude. I'm at 39º North, average less 12º then English observers, so the ecliptic here haves a steeper angle and right after sunset I have about an hour and a half time window, where Jupiter is still at a good hight.

During that time, I can push 240x with my 5mm Ortho and see lots of detail, provided that it's a decent seeing night. Just sow a festoon clear and sharp 2 days ago at 240x.

Besides, eventually it will come around in a few months. Right now Mars is at highest point of the ecliptic before sunrise and Saturn is getting higher and higher. The high mag will always be useful in one situation or the other.

[Tremolo]

Thanks for all the information! To be honest, whether I can see the cloud bands or not I'm still shocked that I can see four moons from my bedroom at 400 million miles away! I guess I'll go for another eyepiece, but even using my 10mm pushes it a bit.

What focal length is your 60mm refractor ?.

It is 700mm

[Capricorn]

700mm with a 10mm EP will give 70x magnification. This should be OK to see a band or 2 on Jupiter. I can see 2 with 60x mag on a 70mm scope.

I wouldn't bother with a smaller EP and so more magnification for the scope you have.

[arad85]

Thanks for all the information! To be honest, whether I can see the cloud bands or not I'm still shocked that I can see four moons from my bedroom at 400 million miles away!

Your bedroom Are you outside Looking through a pane of glass (or two if double glazed) will seriously degrade your viewing....

[Tremolo]

Hey, yeah...um, I guess I didn't take that into consideration at all. It's double glazing, yes. How silly of me. I'm quite new to this!

[pvaz]

Looking from indoors, even with the window open will make any decent scope look like a bad one. As arad said looking through the window glass will degrade the image and, if you open it, the air follow of the hot air getting out will act as the air coming out of a candle flame. If you look over a burning candle everything will be blurred. The more mag you use in this conditions the worst it will be.

The best views are achieved outside, when the line of sight doesn't go near buildings on mountains that release the heat, they gathered during day time. Also if a jet stream in the upper atmosphere is above you, it will affect the views very much.

I forgot to say in my last post: the high mag will also be useful to split double stars, observe globular clusters and for detailed views of the moon.