Newbie question on wide-angle eyepiece

[Malcolm]

I have a 200mm x 1200 mm dobsonian, and two Celestron eyepieces, 6mm and 20mm. I came across a 6mm 66 degree and a 4/10/23mm 62 degree.
Which one of these would be the most useful and is there a lot of difference to what I have now. TIA. :-)

[dannat (Daniel)]

the 6mm 66deg sounds like an orion expanse type eyepiece, they provide quite accptable views for a budget eyepiece.
can you elaborate on the brand name of the 4/10/23 -62 degree fov is an odd number

[Malcolm]

It is by Celestron apparently. http://www.ebay.com.au/itm/271656878...%3AMEBIDX%3AIT

[dannat (Daniel)]

i havnt seent hose eyepieces by celestron before -nor do they see to appear on the company webpage -

[julianh72 (Julian)]

Originally Posted by dannat

i havnt seent hose eyepieces by celestron before -nor do they see to appear on the company webpage -

If you do a Google Search, you'll find a lot of "Celestron" products which also carry the "Chitlan" brand, including a lot of eyepieces that look like these ones. (I've also see them on Amazon with the "VITE" brand; eg http://www.amazon.com/VITE-Aspheric-..._bsnr_499164_6 .) I don't know what "Chitlan" means - but I suspect it's Chinese for "fake".

My personal favourite is this listing for a "Celestron" 20 mm eyepiece:

Chitlan 20mm of bovine anti bovine anti telescope eyepiece magnification positive eyepiece for bovine anti astronomy
http://www.aweldaw.com/p-38836180352.html

(I think it might have lost something in the translation! )

[Malcolm]

Probably a fake then. I'll get this one. http://www.ebay.com.au/itm/191401022...%3AMEBIDX%3AIT :-)

[geolindon (Lindon)]

G day Malcolm,

I doubt you will see much difference at 66* compared to what you have now. I encourage you to do more research, I found this calculator to be very helpful;

http://www.davidpaulgreen.com/tec.html

It is always recommended to get to star parties/groups n try b4 buy. I found that difficult and cheated by seeing what other Dobbers had in their signatures n forum or google searching. There have been some great threads here, in particular I remember a recent contribution from ' mentalasastro?? mental4astro??aka Alex Massey of Gondawana Telescopes.

A couple of gems of wisdom from others;

The ep is half the scope, and

Invest in good eps that you will retain even if you change scope.

I also used an in expensive Barlow to check my seeing v increased magnification.

I am very hapi with my eps (half of em were bought via the classifieds here, pre used) the 100* n 82* even when barlowed have wider fovs that the planet can drift through giving me steady obs between nudges

Cheers, L

[David Niven (David Niven)]

Hi Malcolm
You might check out the swan 72 fov, 9 mm.
Just came across them at Vti webpage for just $49.
Agena sell them for over a Hundred bucks and so do others!

[Tropo-Bob (Bob)]

Malcolm,

Many observers find EPs which have a 2 to 2.6mm exit pupil to be their favourite EPs for general observing. With your scope, this would be EPs in the 12mm to 15mm range.

I recommend that your next purchase be in this range, with my preference being either a 14 or 15mm premium EP.

[Malcolm]

Thanks for all the advice. :-)

[Renato1 (Renato)]

You have an f/6 telescope. My opinion is that a 2 mm exit pupil is best for finding faint galaxies at a dark site - so you'd want a wide-angle (65 to 70degree) or ultra-wideangle (82 degree) 12 mm eyepiece.

But some people prefer a 3mm exit pupil eyepiece for general Deep Sky Object viewing, in which case you'd want an 18mm wide-angle or ultra-wide angle eyepiece.

For looking at planets at high power, you'd want 0.5 to 1mm exit pupils (depending on how steady the atmosphere is) which equates to a 3mm to 6mm eyepiece, delivering 400X to 200X respectively. Though 200X is pretty low for your telescope, which should easily be able to hold 300X at most places on many nights (i.e a 4mm eyepiece).
Regards,
Renato

[dannat (Daniel)]

just to add something to this -apparently the eyepieces were prototypes for celstron but they decided not to list them, there is a thread on the vote aspheric on cloudy nights -they are getting good reviews in long f/l scopes [f8+] esp. considering the price