31mm Nagler - is it big enough?

[DRT]

I recently bought a 31mm T5 Nagler which I have very rapidly fallen in love with. I have also been upgrading my other EPs and now have the following range (some of which are still in the post)...

I bought the 11mm Plössl as a low cost way of testing whether or not my scope can cope with that power as I had to sell my lovely Pentax XW 10mm because I simply could not use it. If the 11mm works I will consider another Televue at the same focal length, but that conversation is for another day.

What I am wondering now is whether or not there is anything to gain by adding an EP with a focal length higher than my 31mm Nagler. If I stick to the TV range, which is my preference, I am limited to the 55mm Plössl or the 41mm Panoptic, both of which have a true field of view of 0.94º, so only give me an extra 0.08º of sky more than the 31mm.

Is it worth spending another £150-£300 to get that extra bit of sky or should I save the money and buy something else?

[Stu]

I would definitely say no to either the 41 or the 55. Hardly any more sky and a larger exit pupil so will just give a slightly more washed out view if you have any LP.

When I had my Mak which had a 4m focal length, I eventually stopped trying to 'fight' the limited fov, and just play to its strengths which are high power planetary and small DSOs such as globulars. I bought a range of TV Plossls and BGO/Hutech's and just benefited from the sharp optics and low scatter. Plossl work well in slow scopes anyway. For me, an 18mm BGO gave x222 which was a lovely high power. A 12.5mm Hutech would give roughly the same in your scope.

You could go crazy and try a 21mm Ethos ;-). Would give about a 2.1mm exit pupil which would be great for DSO observing, x133 and a 0.75 degree field.

In summary, I wouldn't try to achieve any wider fov with the CPC, play to its strengths, and use another scope for wide field.

Cheers,

Stu

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[faulksy]

I recently bought a 31mm T5 Nagler which I have very rapidly fallen in love with. I have also been upgrading my other EPs and now have the following range (some of which are still in the post)...

Screen Shot 2014-06-07 at 23.00.25.png

I bought the 11mm Plössl as a low cost way of testing whether or not my scope can cope with that power as I had to sell my lovely Pentax XW 10mm because I simply could not use it. If the 11mm works I will consider another Televue at the same focal length, but that conversation is for another day.

What I am wondering now is whether or not there is anything to gain by adding an EP with a focal length higher than my 31mm Nagler. If I stick to the TV range, which is my preference, I am limited to the 55mm Plössl or the 41mm Panoptic, both of which have a true field of view of 0.94º, so only give me an extra 0.08º of sky more than the 31mm.

Is it worth spending another £150-£300 to get that extra bit of sky or should I save the money and buy something else?

lovely set of eps, now sell your cpc and get a big dob

[John]

....Is it worth spending another £150-£300 to get that extra bit of sky or should I save the money and buy something else?

No it's not, in my opinion.

Save the money and buy an 8"-10" dobsonian to get some wide angle views with those lovely big Tele Vue's

I've got the 21mm Ethos but I'm still hanging on to my 31mm Nagler as it does show 20% more sky than the big Ethos does and that is worth having I reckon.

[DRT]

I've got an 8" dob already and intend spending some time with her soon as she has been badly neglected since I got the push-button thingy.

I am seriously considering upgrading the small dob to something more serious but probably not for a few months. I feel another thread coming on!

[DRT]

You could go crazy and try a 21mm Ethos ;-)

Was that you trying to be helpful to my bank balance?

[Tinker1947]

Was that you trying to be helpful to my bank balance?

I think you forget about Bank balances with Ethos type EP's either you can afford them or you can't......

[DRT]

I think you forget about Bank balances with Ethos type EP's either you can afford them or you can't......

Not quite. Some, like me, can afford these EPs but feel the impact and sacrifice other things to do so whilst others can afford them without noticing. If I could forget about the bank balance I would not have felt the need to start this thread

[swamp thing]

lovely set of eps, now sell your cpc and get a big dob

^^ This

That's what I'd do. You have an 8" Dob as a second scope. Go big, go Dob, get treat yourself

[alan potts]

I dis-agree with Stu, I love saying things like that, even though I know he had one. The 41mm Panoptic is my wide-field of choice in my LX which is a little longer than yours, it gives me my widest field of view and lowest power, exit pupil is well within any limit as well. It is the only reason I keep this eyepiece for the one scope, though it works in the 2700mm Mak I tend to stick with the 35mm Panoptic for that.

BTW I have a 31mm Nagler and I never use it, even though it is a fine eyepiece.

Alan.

[DRT]

BTW I have a 31mm Nagler and I never use it, even though it is a fine eyepiece.

Yikes! Does that mean that buying too many fabulous EPs with similar viewing experiences causes some of them to spend their life in a box?

That is what I am trying to avoid and is the real reason why I asked this question. I love the 31mm and suspect I would love the Pan 41mm just as much. If there isn't much to draw between them I think I am better having just one.

Feel free to suggest things that would fit nicely into the line-up but assume that 11mm-31mm are the lower and upper limits

Incidentally, my T1 Nagler 13mm is likely to be sold once the Ethos 13mm arrives.

[Stu]

I dis-agree with Stu, I love saying things like that, even though I know he had one. The 41mm Panoptic is my wide-field of choice in my LX which is a little longer than yours, it gives me my widest field of view and lowest power, exit pupil is well within any limit as well. It is the only reason I keep this eyepiece for the one scope, though it works in the 2700mm Mak I tend to stick with the 35mm Panoptic for that.

BTW I have a 31mm Nagler and I never use it, even though it is a fine eyepiece.

Alan.

I wonder if sky conditions play a part in this Alan? Your skies are obviously much better than mine, and I just used to find the 41mm that much more washed out than the 31, but this won't be the case under dark skies.

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[Stu]

Was that you trying to be helpful to my bank balance?

Yep :-)

I once asked this wonderful forum for help to reduce my collection by choosing whether I should sell my 17 or 21 ethos. The messages I received pretty much all suggested keeping both, or buying more! :-)

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[John]

I wonder if sky conditions play a part in this Alan? Your skies are obviously much better than mine, and I just used to find the 41mm that much more washed out than the 31, but this won't be the case under dark skies.

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Thats exactly my experience. When I owned 40mm eyepieces they did not get used because of the light pollution in my area. The Nagler 31 shows practically as much sky but the higher magnification darkens the background.

Having a number of eyepieces that do nearly the same job is a factor as well though I reckon. If you only have one low power / wide field eyepiece then thats the one that ends up in the focuser. If you have a few then often it seems to be the easiest to handle that gets the most use. Magnificent though they are, the Nagler 31 and Panoptic 41 are not the easiest eyepieces to use because of their sheer weight and bulk. I recently acquired a Baader Aspheric 31mm, ostensibly to use with my 6" F/12 refractor where balance is critical,  but the Aspheric, which weighs just 40% as much as the Nagler 31 and is very compact for a 2", is just so easy to pop into the drawtube that I'm using it with all my scopes despite the fact that it shows some astigmatism in my 12" dob 

[Stu]

As a serious part to this question, I would definitely have a think about what you want to see with a wider view.

Big dobs are fabulous, obviously, but even an f4 16" has around 1600mm focal length which would give around 1.6 degrees fov with your Nagler at x 51. This is enough for the vast majority of objects, with the exception of some of the larger nebulae and clusters (the veil and M45 spring to mind).

The alternative is something like a Widefield refractor, 4" f6 or 7 which would get you out to the 3.5 or 4 degrees of sky for a very different view.

So, think about what you want to see with a wider view and then consider whether a different scope would be cheaper!

Stu

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[alan potts]

Stu,

I am almost sure sky is the answer to this, I think you would have though different about yours if there were not so many lamps and other forms of LP. I know where my Brother used to live there was about 2x500w floods next door that came on if you so much as did something like scratch your ear. I am sure there is more than one garden in the UK where this is the case.

Derek,

I think you have a nice selection of eyepieces and all would be used if I had them, the trouble is I have rather a lot more and some do not get out much, they are sort of scope specific. I would  have though if I were you and as Stu pointed out have dark sky, get a Maxvision 40mm, it is a nice wide field eyepiece that will give you just over 1 degree on your scope. If you have dark sky the view is glorious. At F10 there really is no need to spend on Televue in my opinion even though I have. The other that is a good one for you scope would be the 40mm Aero from SW.

Alan

[Stu]

Thats exactly my experience. When I owned 40mm eyepieces they did not get used because of the light pollution in my area. The Nagler 31 shows practically as much sky but the higher magnification darkens the background.

Having a number of eyepieces that do nearly the same job is a factor as well though I reckon. If you only have one low power / wide field eyepiece then thats the one that ends up in the focuser. If you have a few then often it seems to be the easiest to handle that gets the most use. Magnificent though they are, the Nagler 31 and Panoptic 41 are not the easiest eyepieces to use because of their sheer weight and bulk. I recently acquired a Baader Aspheric 31mm, ostensibly to use with my 6" F/12 refractor where balance is critical, but the Aspheric, which weighs just 40% as much as the Nagler 31 and is very compact for a 2", is just so easy to pop into the drawtube that I'm using it with all my scopes despite the fact that it shows some astigmatism in my 12" dob

Agreed John. Just recently I'm finding myself doing whole sessions with my travel case which has a 24mm Panoptic, 20, 15 & 11mm TV Plossls, 5 to 18mm BGO/Hutechs and a 3 to 6 Nag zoom.

They are all very similar in weight so don't affect balance and give lovely views. With a VIP Barlow I can extend the eye relief on the Orthos and I really enjoy using them.

I tend to keep the heavy guns for those rare nights away under dark skies, or if there is a particularly dark night at home.

Stu

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[Stu]

Just one more thought! I think the set you have are fine for the CPC1100, you've got most things covered. It is probably worth looking at how they work in the 10" and where your gaps are there.

There is plenty of talk on here about only needing 3 or 4 eyepieces. That is probably true with one scope, but where you have differing focal lengths, on particular a large dob or Mak/SCT combined with short focal length fracs you need more to cover all bases.

As an example, a 31mm nag in my apo triplet gives a wonderful 3.68 degree field to take in the whole of the Veil. In my Mak it gave x125 and became fabulous for globs, or even planetary observing!!

Stu

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[DRT]

Thanks, guys, lots of good stuff and food for thought here.

Now all I need is a night when the sun goes down for more than an hour or two

[swamp thing]

Seriously

I considered the big pan for use in my large scope where size of field is more important, at these powers it's more about fitting things in than exit pupil, but it simply doesn't offer any real advantage over the Nagler. It's not a big enough field to be worth sacrificing exit pupil for.

I don't think the big pan offers you anything you haven't already got in a better package with the Nagler myself and I'd keep the Nagler. Plus if you ever go big and fast with a Dob the Nagler is the eyepiece to have.

[DRT]

I've been out looking at the Moon this evening with the Nagler 31mm. The Moon fits in the FOV comfortably in the CPC. I then tried it in the 200p Dob and was amazed at just how much sky I could see. The FOV had a bright star in it as well as the Moon but the star wasn't visible to the naked eye as it wasn't yet dark enough. A quick look at Stellarium revealed that it was Spica...

I am rubbish at working this stuff out but can someone who knows these things please tell me roughly what represents in terms of true field of view?

I can now see Spica with the naked eye and drawing an imaginary circle around it and the Moon gives a huge area of sky. Are there any DSOs that would not fit in that view?

[Moonshane]

I 'discovered' long ago that for the price of a 130mm or 150mm f5 (maybe £50-100 max) you get a wonderful wide field and at a price much cheaper than a huge wide field eyepiece which weighs and cost a ton.

[Stu]

If your scope is the f5, 1000mm f/l then it would be 2.54 degrees. This is a snapshot from SkySafari.

To answer the question, most DSO's would fit this fov, except things like the Veil.

Stu

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[DRT]

If your scope is the f5, 1000mm f/l then it would be 2.54 degrees.

The 200p is 1200mm / f5.9 - presumably that makes a difference?

[John]

The Nagler 31mm gives a 3.83 degree true field with my ED102 F/6.5 refractor and the whole of the Veil Nebula will fit in with a little room to spare around the edges of the field of view. In the same scope the 21mm Ethos gives a true field of 3.16 degrees and the E & W segments can be seen within the field but are right up against the edge of the field stop and it's just not quite as nice a view in my opinion. The Nagler 31 earns it's keep here 

The F/5.9 scope will show a little less sky than an F/5 that Stu has assumed.

As Shane says, sometimes getting another scope is the most effective solution