5mm EP OR 10mm EP + 2x barlow??

[abumuhannadh]

Hi,

what is better? a 5mm eye piece or a 10mm eye piece with a 2x barlow?

[yeti monster]

I guess that would depend upon the quality of the EPs and Barlow in question.

[Demonperformer]

In theory a 5mm should give a better result than 10mm+barlow, but whether the difference will be noticeable will be largely dependent (as per previous comment) on the quality of the ep/barlow being used.

Another thing is, depending on the scope you have and your local seeing conditions, 5mm may give you a magnification which you cannot use a lot of the time, whereas if you go for the barlow option, you can always use the 10mm on its own if conditions do not warrant the 5mm.

IMO go for a 10mm (which will always be useful) then add a barlow. If you are using the combination enough to warrant it, consider a 5mm at that stage.

My 2p ...

[Moonshane]

another consideration is eye relief. if you look at some eyepieces (eg plossls) the eye relief of a 5mm would be very tight but a 10mm barlowed would be more comfortable to use. as others have said though, the quality of both barlow and eyepiece has to be decent.