Lens for MEADE etx 80?

[WonderMan]

Hi everyone. Ive got a meade etx 80 telescope and was wondering what lens would i need for more magnification? Any info or adviec about what i would need?

Thanks!

[WonderMan]

Eyepiece*

[John]

Which eyepieces do you have at the moment ?.

[NGC 1502]

Hi and welcome to SGL. To find the magnification any eyepiece will give,

divide the focal length of the telescope by the focal length of the eyepiece.

I've just looked at an advert for the ETX 80, it said that the supplied eyepieces

were 26mm and 9.7mm. If that is what you have, then dividing those numbers

into the 400mm focal length of the telescope gives the magnifications as below.

Your telescope also has a built in barlow lens, when that is in use, it will double

the magnification.

400/26 = 15x, with the barlow in use, 30x

400/9.7 = 41x, ---------------------, 82x

I think I would have a few sessions with the scope, and see how you get on,

a lot can be seen with that range of magnifications. You could get a 6mm

eyepiece to give 67x and 133x, but I personally wouldn't go higher than that,

but owners of this scope will hopefully chime in with their experiences as to

what this telescope is capable of. I think a smaller sharper view is always

better than a larger but fuzzier one.

Best regards, Ed.

[ronin]

The scope is 80mm f/5 as I recall. It is also an achro, not ED so don't expect similar performance. I would say that a 6mm would be about the most usable, giving 400/6=66.6x mag.

A 5mm will give 80x.

If you go smaller I doubt that the image would be much use, although you can try.

Plossl's will not be a great deal of use at that small a size, you will end up with the eyepiece very close to your eye. So I suggest that you consider a planetary or two of say 6mm then if you find it workswell you could try a 5mm.

At these sizes it is a case of trial and error until you buy one that simply does not work.

[WonderMan]

I have the 26mm and 9.7mm which are the eyepieces that come with the telescope

[WonderMan]

So a 6mm would be best? i know that etx 80 is not the best telescope for viewing planets with great detail. So if i wanted more sky i would need a better scope?

Thanks for the replies

[ronin]

Have the ETX70, very similar.

Found that a 4mm plossl EP was basically useless, as in utterly and completely useless. The 6mm was the one I use the most.

I do have a 5mm but somehow think I never used it, may have purchased it later. So cannot really say anything about that.

Now to the oddity, would like to try it at 100x, meaning a 3.5mm EP. Knowing that a plossl is no good I will one day try a planetary. It's only money, and should be good on a decent ED refractor I have.

I have a 4.3mm (81x) that works pretty good in it, just not sure what the basic design type is. So hoping that a 3.5mm planetary will be OK.

As I said it is trial and error. Fortunately if too much for the 70 then I can use on the ED refractor without problems.

If you wanted better then (assuming a refractor) you are looking at say 100-110mm ED. I would go for something in the f/7 range. f/5's are simply pushing the ability of the glass too much. I will also say that if you can keep the 80. You will find that it is easy to set up and use and I would say that you will still use it the most. A 4mm planetary will probably be acceptable on the 80, but should be very good on an f/7 100ED.

[WonderMan]

Hi Ronin, sorry but is it ok if you can simplify that last paragraph pls? im kinda a newb to astronomy and dont understand some of the stuff

Thanks

[WonderMan]

HR Planetary 6mm - High End eyepiece for telescopes: Amazon.co.uk: Electronics

Would this be a suitable eyepiece?