best 40mm

[spoty1]

Hello.

i have skywatcher 8" telescope and i was thinking about buying a low power eyepiece, the minimum magnification is about X30, so the largest eyepiece i can use is a 40mm, what is the best 40mm eyepiece out there?

thanks...

[swamp thing]

What kind of budget are we looking at here? There's an enormous range of eyepieces out there to suit all budgets

[jabeoo1]

Bear in mind that if the magnification is too low it can produce an exit pupil that is large.  This can be an issue in scopes with a central obstruction like the newtonian you have.

I am not saying x30 won't work but just consider these factors !  

[ronin]

Suspect at 40mm the "best" is the TV plossl.

However the field of view of a 40mm is restricted by the shiny metal bit on the bottom, it acts like a field stop.

So the result is that the view is almost identical to the 32mm.

So the difference is the 40 gives lesser magnification but has lesser field of view that results in the same field of view to you.

In effect is it low magnification or wide field of view that you want?

If the latter then the 32mm and the 40mm are the same.

[John]

In the 1.25" format I don't think the 40mm focal length is worthwhile because a 32mm will show just as much sky and the slightly higher magnification gives a slightly darker background.

[Mr Spock]

Yes, if you are 1.25" only you'll need the 32mm eyepiece - 40mm has too small a field stop. 40mm only becomes useful in 2" fittings

[michael.h.f.wilkinson]

If you go to 2", the 40mm TMB Paragon is great (regret selling that). The SW Aero is a clone, and should be good too. I now have a 42mm LVW, also very good.

[russ.will]

Hello.

i have skywatcher 8" telescope and i was thinking about buying a low power eyepiece, the minimum magnification is about X30, so the largest eyepiece i can use is a 40mm, what is the best 40mm eyepiece out there?

 

thanks...

You don't state whether the SW 8" is the F5 Explorer 200p, or the F6 Skyliner 200p Dobsonian? Both will take 2" EPs, so that's not really the issue. You might get away with a 40mm EP in the Skyliner if you have young eyes, but it definitely would be excessive in the Explorer.

The old 7mm exit pupil rule is more of a rule of thumb (you can bend it) but you won't get very good views, regardless. The sky will appear bright, in all the the darkest locations and the view will look low contrast. So whether we're talking 1.25" or 2", I'd say the best 40mm is something in the 30-32mm range

And when you mean best, did you have a price limit in mind? Because in the range suggested, the best EPs would be the Televue Nagler 31mm with the Explore Scientific 30mm 82deg a very, very close second in quality, if not so much in price!

Russell

[spoty1]

thanks for the replays... i have the sky watcher collapsible 8".  5.9 focal length.

the telescope can take 1.25 and 2 inch eyepiece..

[russ.will]

Budget?

Russell

[deepspacehunter]

The MEADE 40mm SWA.... one AWESOME EP...

Mark

[russ.will]

Got one - or rather the same thing under the Maxvision label - and I still wouldn't recommend it for an 8" Newt. Great EP in my SCT, but in a Newt? It's out of it's comfort zone.

At a near F6 of the OPs scope, he'd be better off with the 34mm or (and this would be my bet) the 28mm SWA under the Maxvision label. With the Euro's weakness against the GBP, that would land for approximately £90. Wrap a Meade band around it and it's still a very good EP, but over £200. The MV is a no brainer in value for money terms.

I might add that having had all of the MVs and a 300mm F5 Dob (and so a longer FL than the OP's scope) at the same time, I found I frequently didn't bother with the 2" EPs and found the 24mm to be my finder workhorse. I deeply regret selling that one.

Russell