Guess what? Eyepiece questions

[ohoward]

I have recently acquired a Celestron Nexstar 4SE. Due to cloudy skies i have been unable to do any viewing as yet, other than a little terrestrial when alligning its red dot finder.

The scope comes with a Celestron E-Lux 26mm Plossl and already I'm thinking of expanding my 'set' of eyepieces. Does anyone have any suggestions? Should I buy 1 or 2 seperate eyepieces and a 2x Barlow, and if so what sizes? Would a 4mm eyepiece be stretching the limits of what this scope can achieve?

Any and all help much appreciated.

[DanDare]

Hi,

Buying say two more eyepieces and 2x Barlow is a good idea and will give you a reasonable range.

From an internet search I see that the 4SE has a focal lenght of 1325mm and with a 4mm eyepiece this will give a magnifaction of x331 which I think will be too much for your scope. I believe the general rule of thumb is x50 per 1" in excellent seeing and with our indifferent skies this could be difficult to achieve, probably x40 per 1" is nearer the mark.

Hope this helps, I'm sure other will be able to give you their input.

Have fun using your new 'scope!

Roy

[Badgerjc]

Try having a look at these ep's i have just got mine and they are great value for money mate!! A good buy for sure!!

Hope this helps!!

Badgerjc

http://www.firstlightoptics.com/proddetail.php?prod=CelestronEPkit

[jgs001]

The other option is to keep an eye on the For Sale sections on the forums and maybe astro buy and sell. Then you can grab some ep's possibly quite cheaply that will get you up and running.

[The Warthog]

With such a long focal length, almost any eyepiece will give very good sharpness. For example, the 20mm EWA that I am offering on the for sale page, is a bit fuzzy round the edges in my f/5 scope, but sharp in my f/9.5 scope. Your scope is about f/13, and that will sharpen up any decent ep. If in doubt, though, stick with Plossls, you can't go wrong.

[jgs001]

Worth taking a look <a href=http://www.astrobuysell.com/uk/propview.php?view=16709>here</a>

[John]

I think a 2x barlow lens would be worth getting - your 26mm / 51x eyepiece would then also be effectively a 13mm / 102x eyepiece when used with the barlow lens. I think I would also invest in an 18mm eyepiece which would give a nice mid-range power of 75x on it's own and 150x with the barlow lens. After that you might want to think about a 7mm (192x) eyepiece which is the max you will be able to use effectively - and then only on good, clear nights. Those would give you a good range of powers in your scope.

John

[The Warthog]

I don't disagree with you, John, but I would suggest a 13 - 15mm ep, which with the Barlow will just about max out the scope, rather than having an ep you can use only when the seeing is exceptional.

[John]

I don't disagree with you, John, but I would suggest a 13 - 15mm ep, which with the Barlow will just about max out the scope, rather than having an ep you can use only when the seeing is exceptional.

That's a sound approach WH - nothing worse than a piece of kit that gathers dust !.

John