advice needed, 5mm, 6mm eyepiece

Hi Guys

I need a little piece of advice, I want to get a 5 or 6mm eyepiece primarily for my 8"f5 dob. I do not want to break the bank but I do want something that will give decent enough views. I was contemplating a 5mm plossl from meade or celestron but, I was also reading this thread
www.irishastronomy.org/boards/viewtopic.php?t=2719
which has me thinking that since my scope is f5 I need to invest in a much better 5mm than a standard plossl. Any advice and opinions would be greatly appreciated. the 5mm I have at the moment is the one that came with the 70mm skylux and is not the best at all.

Hi Trevor,

I have both a 4mm and 6mm orthoscopic eyepiece. I think they're supposed to be quite good at high magnification (orthoscopic eyepieces that is). They both seem in good condition to me and are in their original box. They cost me £58 and £50 respectively back in the day. If you're interested you can PM me whatever you think is a reasonable offer as I've no real need for both. Only if you're interested of course...

Regards,

Dan

PS That Lidl scope is a real winner!

Eh, I hasten to point out that it's a 1.25" eyepiece. On re-reading I see you might be after a 2".

Sorry if that is the case...

Dan

Trevor --

The Plossl design (and other relatively-narrow-field designs such as orthoscopics and monocentrics) will have an easier time at f/5 than wider-field designs.

That being said, a Plossl in the 5 - 6mm range is going to have vanishingly short eye relief. I'd guess on the order of 4mm. My eyelashes are probably 7mm+, so I like to stay in the 8 - 10mm range for eye-relief. (The volcano-tops found on many orthos and the RKEs keep my eyelashes away, but I haven't seen many Plossls with that design. And the orthos have the down-side of an even narrower field of view than the Plossls.)

Do you have a decent 10 or 12mm that you can barlow? That might be another way to go....

-- Jeff

Thanks for allyour advice guys, all will be taken under consideration, before purchasing.

I've got a meade series 4000 6.7mm eyepiece and its like looking into a pin hole. I could not recommend it really, its not a comfortable one to use.