Eyepieces for Orion XT8

Well, my son and I had a very quick viewing of the moon and Mars last night. (The clouds don't seem to want to give up in NJ.) But, from the brief viewing we had, we noticed we needed more magnification to view the moon's craters and Mars up close. We have the eyepieces that came with the scope which are 25mm (48x) and 10mm (120x).

So, if we want more magnification, which eyepieces would you suggest? Should we go for a Barlow? Or, should we get a 4mm (300x) or 5mm (240x) eyepiece? I know the rule of thumb for maximum magnification is about 50x or 60x per inch under the best seeing conditions so I don't want to go too high, do I?

Does a quality Barlow give the same image as an equivalent eyepiece?

On the other extreme, I could see getting a really low power eyepiece for a larger field of view for galaxies and nebula. Perhaps, a 2" one? Any suggestions on this?

I know Televue seem to make the best. But, will I notice the difference in my scope?

Please suggest brands, types, etc.

Thanks.

Doug

Hi Doug,
If you want higher power than the 10mm provides, I think a barlow would be good. The reason for this is that the smaller EPs have very tight eye relief unless you buy the more expensive EPs with 20mm eye relief. This can be a big problem for some. The Barlow actually increases the eye relief so that the smaller focal length is less of a problem.
Also the exit lens is quite small in a 4-7mm Plossl design. This is like looking though a peep hole and is not that easy for kids I find.
A nice Orion Shorty Plus Barlow http://orion.telescopes.com/products/Orion_Shorty-Plus_2x_3-Element_Barlow_Lens_37049.html would be good or just about any other like the Celestron Ultima barlow shown here. http://www.buytelescopes.com/product.asp?t=55&pid=436&m=
This would give you 25mm (48x) 12.5mm (96x) 10mm (120x) & 5mm (240x) from just the two EPs. This should be plenty of magnification for any night.

Barlow next, and then an even longer (than 25)for wider views--(although watch out you don't go too long so you don't get the black spot). Save up for wider apparent field of view in future eyepeices.

It is pretty easy to overpower a scope when you already have a 10 mm eyepiece. The next shortest starts to give you too much magnification. Reember, you are looking for detail and not size.

Alex

Just to mimic what has already been said

Floyd said get a barlow, I agree

Floyd said stick with the 1 1/4" EP size I agree

Floyd and Alex said to get a lower power EP, like a 32mm after the Barlow, I agree

Now here is another reason, The barlow will turn the 2 EP's you have into effectively 4 EP's and when you get the 32mm you will then have 6.

I guess I'll chime in with some recommendations on eyepieces as well. My experience with 8" newtonians has been that the best views of planets are generally at magnifications no higher than 160x to 200x - ususually the atmospheric conditions don't allow for much more detail at higher powers and hand tracking with a dob becomes a pain at higher powers. I would suggest getting another plossl in the 13 to 15mm range along with the Orion Shorty Plus 2x barlow - a TeleVue 15mm plossl can be had in great condition for under 60 bucks on Astromart. For a wide field, low power eyepiece I would consider one of the 2" 30mm 80deg. eyepieces like this one:
http://www.buytelescopes.com/product.asp?t=&pid=8409&m=
It will give you that nice "spacewalk" effect for a reasonable price and provide much more field of view (about 50% more) than a 1.25" equivalent. The stars at the edge won't be perfectly sharp but who cares - it's still a lot of fun to look through one.

Joplin

The group has great ideas but please also look at Rini eyepieces. I have a pair 30mm Rini and love them. They sell for $30 each. The web site for his eyepieces is http://proptics.ieasysite.com/paul_rini_scientific_010.htm

Steve

Wow! So many suggestions. I guess I asked for it.

I do like the Barlow suggestion since I wear glasses. I would like more eye relief. So, my first purchase will be a Barlow.

And then, maybe a 32mm Plossl. I guess I'll stick with the 1 1/4" EPs for now.

Thanks again.