24mm eyepieces lowest power useable on f4.7?

[Tot]

Hoping to get a 254mm (10 inch) , f4.7 dob reflector soon. Hoping to see wide-field views of clusters etc. I'd like the widest field of view my budget and scope will allow. Would a 24mm eyepiece be the lowest power to use? I'd love to get huge wide fields as with TV Delos and Ethos, but my budget for this eyepiece is around £150. Thinking maybe Hyperion? Any help much appreciated.

Tot

[cutepetgroomer]

okay well, I have a scope with a 70mm aperture and a 300mm focal length so that would be 4.28 and all these are eyepieces I have used with it.. : 40mm, 25mm, 20mm,10mm,6mm and 4mm as well as a 3x barlow. so I would think you could definitly try a 40 mm..  I am looking upgrading to a bigger scope (90 mm is what I tried out for a week and loved it)

[Dave In Vermont]

24mm = almost 50X in a f/4.7 Newt. The magnification is not a problem on the lower tier. It's the upper magnification that can be more problematic. But the Field Of View - FOV - can present problems with vignetting. The Hyperions have a 68-degree FOV, and some think this will present problems. Others don't agree. I'd wait for more opinions to roll in before 'pulling the trigger.'

However, the Hyperions are excellent eyepieces.

Clear Skies,

Dave

[jetstream]

The 23mm Luminos works well and is in this price range, FLO sells them for 165 pounds.  There were some negative reports on this series of EP's but they are good IMHO, mine is anyway. At f4.7 there may be some astigmatism showing at the outer edge, and there will be coma for sure. The open cluster views with a widefield are amazing and this eyepiece performs well with UHC/OIII filters. Heavy sucker though.

The more expensive 24mm ES 82 is another great option, maybe a used one can be found, good luck Tot, you are on the right track.

[Joves]

I'd have absolutely no hesitation in recommending the 24mm Panoptic. Cracking eyepiece and would fall within budget. I'd go so far as to say that the 24mm Pan is probably the eyepiece in 1.25 format that impresses me the most and i have quite a few.

[Tot]

I'd have absolutely no hesitation in recommending the 24mm Panoptic. Cracking eyepiece and would fall within budget. I'd go so far as to say that the 24mm Pan is probably the eyepiece in 1.25 format that impresses me the most and i have quite a few.

I should have said that I'm probably going for a 2" format eyepiece to try to get the feeling of "dipping your head in a bucket of stars". :-) Those 24mm Panoptics look ideal though for a 1.25" size.

[Tot]

The 23mm Luminos works well and is in this price range, FLO sells them for 165 pounds.  There were some negative reports on this series of EP's but they are good IMHO, mine is anyway. At f4.7 there may be some astigmatism showing at the outer edge, and there will be coma for sure. The open cluster views with a widefield are amazing and this eyepiece performs well with UHC/OIII filters. Heavy sucker though.

The more expensive 24mm ES 82 is another great option, maybe a used one can be found, good luck Tot, you are on the right track.

Thanks Gerry. I had been considering that Luminos. I like the idea of a 2" widest angle possible eyepiece and that looks there or thereabouts. Does look huge, though.

[Tot]

24mm = almost 50X in a f/4.7 Newt. The magnification is not a problem on the lower tier. It's the upper magnification that can be more problematic. But the Field Of View - FOV - can present problems with vignetting. The Hyperions have a 68-degree FOV, and some think this will present problems. Others don't agree. I'd wait for more opinions to roll in before 'pulling the trigger.'

However, the Hyperions are excellent eyepieces.

Clear Skies,

Dave

Thanks Dave. I'll see what more folk have to say!

[Tot]

okay well, I have a scope with a 70mm aperture and a 300mm focal length so that would be 4.28 and all these are eyepieces I have used with it.. : 40mm, 25mm, 20mm,10mm,6mm and 4mm as well as a 3x barlow. so I would think you could definitly try a 40 mm..  I am looking upgrading to a bigger scope (90 mm is what I tried out for a week and loved it)

Wow. It was my newbie understanding that anything more than approx 5 times the f ratio would be wasted. I would have thought that a 40mm would be too much for a f4.7 newtonian but I'm probably wrong! :-)

[cutepetgroomer]

Wow. It was my newbie understanding that anything more than approx 5 times the f ratio would be wasted. I would have thought that a 40mm would be too much for a f4.7 newtonian but I'm probably wrong! :-)

I have had the approach of buying second hand eyepieces and see if it will work.. so far I have been very lucky that way (also second hand is much cheaper as well)

[Paul73]

The 28mm MaxVison 68° 2" is well liked in that scope and performs well when properly dark.

Although I like mine. I will be trading it in at some stage for the ES 82° 30mm or the 31mm Nagler (in the event of a moderate lottery win).

Paul

[Joves]

I should have said that I'm probably going for a 2" format eyepiece to try to get the feeling of "dipping your head in a bucket of stars". :-) Those 24mm Panoptics look ideal though for a 1.25" size.

Oh, well thats easy then... 21 Ethos!!!

[swamp thing]

Wow. It was my newbie understanding that anything more than approx 5 times the f ratio would be wasted. I would have thought that a 40mm would be too much for a f4.7 newtonian but I'm probably wrong! :-)

No you are not wrong. The exit pupil of a 40mm eyepiece used in a f/4.7 newt (8.5mm) is way to big and you are wasting light. There is also a chance you'll start seeing the secondary shadow when viewing bright objects. TBH you can get wide enough 32mm eyepieces to get any object you want in a 10" f/4.7 newt.

[Tot]

Oh, well thats easy then... 21 Ethos!!!

If you're buying, I'll take one!

[Tot]

No you are not wrong. The exit pupil of a 40mm eyepiece used in a f/4.7 newt (8.5mm) is way to big and you are wasting light. There is also a chance you'll start seeing the secondary shadow when viewing bright objects. TBH you can get wide enough 32mm eyepieces to get any object you want in a 10" f/4.7 newt.

So I could go to a 2" 32mm eyepiece and get the widest field possible for my scope?

[swamp thing]

Depends on the AFOV (apparent field of view) of the eyepiece.

A 32mm 50deg plossl has the same FOV as a 24mm 68deg eyepiece. This in turn has the same FOV as a 20mm 82deg eyepiece.

So as you can see a 24mm 82deg eyepiece would be wider still. Obviously if you can get hold of a 32mm 82deg eyepiece the field is enormous. They are also huge, heavy and expensive.

[Tot]

Depends on the AFOV (apparent field of view) of the eyepiece.

A 32mm 50deg plossl has the same FOV as a 24mm 68deg eyepiece. This in turn has the same FOV as a 20mm 82deg eyepiece.

So as you can see a 24mm 82deg eyepiece would be wider still. Obviously if you can get hold of a 32mm 82deg eyepiece the field is enormous. They are also huge, heavy and expensive.

With a budget up to £200 is this the sort of thing you'd recommend?

http://www.telescopehouse.com/acatalog/Explore_Scientific_30_mm_82__water_proofed.html

[Paul73]

Yes. Good choice.

Telescope House are sold out at the moment but Explore Scientific themselves still had some the other day.

Paul

[swamp thing]

With a budget up to £200 is this the sort of thing you'd recommend? http://www.telescopehouse.com/acatalog/Explore_Scientific_30_mm_82__water_proofed.html

Not really it's a great eyepiece but it's huge and heavy requiring loads of faffing about with extra counterweights every time you get it out of the case.

I have the televue version and seldom use it in my 10" scope for exactly the above reason. My 'go for' eyepiece, the one that goes straight in the Focuser every single time I use my 10" Dob is a 20mm 82 degree one. This is as wide as I need to go for 99% of objects in the sky.

[Gazabone]

I have a 24mm Hyperion which I love on my 10" Dob if that's any help :-)

[John]

With respect to the previous poster, I'd not recommend a Hyperion in an F/4.7 scope. They show quite a lot of astigmatism even in F/6 scopes. The Aspheric Hyperions are the same. They are nicely made eyepieces but not suited for faster scopes.

Up to 30mm is a reasonably practical focal length eyepiece to use in the scope but, if you have much light pollution where you observe you will find 20mm gets more use as Steve suggests because the background sky will seem darker.

[Paul73]

Steve.

Yes good point. It is a big beast. But, if you want big wide quality views for aprox £200. You've got to accept some compromises.

I'm getting it because I'm after the context and multiple objects. For a quick swap in and out eyepiece, then 24mm 68° or a slightly shorter 82° will do the job.

Paul

[John]

The Explore Scientific 28mm 68 degree eyepiece might be worth considering. It gets good feedback when used in a 10" F/4.7 dob from an experienced observer (RikM) here:

http://stargazerslounge.com/topic/178019-es-28mm-68%C2%B0-any-good-at-f47/

[rwilkey]

Hoping to get a 254mm (10 inch) , f4.7 dob reflector soon. Hoping to see wide-field views of clusters etc. I'd like the widest field of view my budget and scope will allow. Would a 24mm eyepiece be the lowest power to use? I'd love to get huge wide fields as with TV Delos and Ethos, but my budget for this eyepiece is around £150. Thinking maybe Hyperion? Any help much appreciated.

Tot

Hyperions are no good at f/4.7, they will be fuzzy at the edges.  I am in favour of the ES82 series 24mm, this will be great in your f/4.7.

[Tot]

With respect to the previous poster, I'd not recommend a Hyperion in an F/4.7 scope. They show quite a lot of astigmatism even in F/6 scopes. The Aspheric Hyperions are the same. They are nicely made eyepieces but not suited for faster scopes.

Up to 30mm is a reasonably practical focal length eyepiece to use in the scope but, if you have much light pollution where you observe you will find 20mm gets more use as Steve suggests because the background sky will seem darker.

Ok, so I'm best not to go overboard, going much beyond 20 - 24mm, as here is light polluted? If I went to 30mm I'd have a wider view but things would looked "washed out"? My compromise then might be a 24mm, wide view but not troubled by LP so much?