Switch to full style
Got a beginners' question? No matter how elementary, our friendly forum community and magazine writers will answer it.
Post a reply

Eyepiece help

Fri Nov 02, 2018 9:01 pm

I have been researching on eyepieces for a day or two now and I can not come to a conclusion on what to get. I have an Orion space probe 130st. The focal length is 650mm and I am looking to view planets mostly Saturn as its the planet I took most interest in. If anyone has a good recommendation it would be great to hear it thank you.

Re: Eyepiece help

Fri Nov 02, 2018 10:44 pm

The usual advice is that the rings are visible with about a 25x magnification and you should be able to separate the rings from the planet at 50x
However, I would assume that is the case for when Saturn is closest to us - and at the moment, it's only at about 80% its max size.
So, if you want to see Saturns rings relatively distinctly, you should aim for about 60x magnification - which would require a 10mm focal length eyepiece.

I believe that low f/ratio telescopes (like yours) are more demanding of eyepieces, but I'd expect you would probably get good results with Saturn if you used a medium-low end eyepiece like Celstron's X-Cel 12mm or 9mm EP that will give you 54x / 72x respectively. These should be good enough for observing a planet - I can't guarantee how well they'd work across the whole field of view for your f/5 scope; but they work very well with my f/10 and f/12 scopes,

If you get a 2x Barlow lens, you could effectively get a second EP to give you double the magnification without so much expense.

As your scope is f/5, you would normally expect the shortest focal length eyepiece that you can usually get good results from would be a 5mm EP - any shorter than this and your viewing is likely to deteriorate unless the skies are particularly good.

However, with Saturn being as low as it is at present, your best views will have to wait until next year - but they will improve gradually year on year over the next few years

Re: Eyepiece help

Sat Nov 03, 2018 12:27 am

Wow thank you so much that was a great response and so quickly. So you mentioned the Celstron's X-Cel would that also be good for other planets as well or just Saturn?

Re: Eyepiece help

Sat Nov 03, 2018 11:33 am

BawlNova wrote:Wow thank you so much that was a great response and so quickly. So you mentioned the Celstron's X-Cel would that also be good for other planets as well or just Saturn?

Yes, it should be good for the other planets too, it's just that they're smaller.

I can't say whether they're the best for their price range, but i reckon they're good quality at a reasonable price - about £70.

If you give one of the online vendors a phone call, you could ask what they would advise; they should have a good idea of what will work for your scope.

Re: Eyepiece help

Sat Nov 03, 2018 1:56 pm

Well I am not to bothered about the price at the moment.As I am willing to pay for quality

Re: Eyepiece help

Sat Nov 10, 2018 11:20 pm

BawlNova wrote:Well I am not to bothered about the price at the moment.As I am willing to pay for quality


Quite honestly, I would not consider buying expensive eyepieces unless you were planning to buy a high quality telescope later on.

With a focal ratio of F/5, your telescope is better suited to wide field views, such as star clusters and galaxies.

I have a 32mm Skywatcher Plossl and some Moonfish Group eyepieces. They perform well with my 127mm Maksutov and Coronado PST.
Post a reply