Eyepiece for sw250 F4.7

[Adam Barnsley]

Hi all. 

I would like to buy my first eyepiece, but there is a problem which?

My choices are:

Nagler 22mm

APM HDX XWA 20mm

TS XWA 20mm

Myraid 20mm

ES 20mm

( Or used Ethos 21mm if i find any)

Second choices :

Delos 17.3mm

Morpheus  17.6mm

Delite 18.2mm

I would like to ask for suggestions helpful when choosing

Adam.

Edited December 12, 2019 by Adam Barnsley

[Louis D]

I tend to use powers between 75x and 100x the most often, so I would recommend getting a 12mm to 16mm premium eyepiece.  As such, there's the 13mm APM HDC XWA, 12mm ES-92, 13mm Nagler T6, 16mm T5, 12mm and 14mm Delos, etc.  I would avoid the 14mm Morpheus as it is the weakest of the line with some field curvature and edge astigmatism.  I would also avoid the 14mm Pentax XW due to field curvature.  Your choice will depend on the amount of eye relief you like to have, the size of the apparent field of view you like to see, the weight and bulk you and your scope will tolerate, and the price your wallet will bear.

[John]

I'm sure that you will get lots of help and suggestions with this choice Adam.

In that niche I currently have:

21mm Ethos

17mm Explore Scientific 92 degree

24mm Panoptic and 17.3mm Delos (for when I want to use 1.25 inch eyepieces only)

All are excellent in my opinion.

I've also owned an used others in this niche, again which are very nice:

22mm Nagler Type 4

20mm Nagler Type 5

20mm Explore Scientific 100 degree

20mm Myriad (which is the same optically as the APM XWA 20mm by the way)

The others you list are no slouches either.

You are going to be spoiled for choice. To narrow things down a bit:

- do you have a preferred budget range ?

- do you wear glasses when observing ?

- does the weight of the eyepiece matter to you (some of these weigh 1.2 kg) ?

My current dobsonian is a 12 inch F/5.3 but I've also owned a 250PX F/4.7. I believe all the eyepieces you list will work well with the scope but you might want to think about a coma corrector for the ones with an 80 degree or wider apparent field of view because at F/4.7 coma (from the scope mirror) will be seen in an ultra wide field even if the eyepiece is very well corrected. (edit: especially if the eyepiece is well corrected !)

I'll look forward to hearing about the choice you eventually make

 

[Adam Barnsley]

10 minutes ago, Louis D said:

I tend to use powers between 75x and 100x the most often

I chose 20mm as the first to get used to using the telescope (inverted image) I'm used to the binoculars. It's just my thought, maybe I'm wrong?

[Adam Barnsley]

11 minutes ago, John said:

- do you have a preferred budget range ?

400£

 

12 minutes ago, John said:

do you wear glasses when observing ?

No.

Thank you for your answers. Is not easy to make a choice.

[Ruud]

I'd go for the Morpheus 17.5 because that's an epic eyepiece which one needs to have anyway (because it is so engaging). It has a nice wide field with good eye relief, a well behaved exit pupil and great contrast and sharpness. It's an immersive and comfortable eyepiece. You'll certainly use it a lot.

[Adam Barnsley]

16 minutes ago, John said:

- does the weight of the eyepiece matter to you (some of these weigh 1.2 kg) ?

it does not matter to me. How will the Dobson and focuser handle such a weight?

[Louis D]

1 hour ago, Adam Barnsley said:

I chose 20mm as the first to get used to using the telescope (inverted image) I'm used to the binoculars. It's just my thought, maybe I'm wrong?

I generally recommend putting the most money into the eyepiece likely to get used the most often, thus my recommendation.

I would avoid spending a bunch of money in the 20mm range as you're likely to skip past it in the future for higher powers.  In that range, I would recommend the 22mm Omegon Redline SW, TS Optics Expanse WA, AstroTech AF70.  It served me very well for years before upgrading to a 22mm Nagler T4, but I still find it easier to use eyeglasses than the NT4.  You see that it holds its own pretty well against the vastly more expensive NT4 below at f/6 at least.  Perhaps a bit less so at f/4.7.

[Rob Sellent]

With my 250 f5 Dob, I tend to use eyepieces with focal lengths of 20mm, 14mm and 10mm respectively offering 4mm, 3mm and 2mm exit pupil. With 3 eyepieces and a decent x2 Barlow, I feel I really don't need anything more for a decent night's general observing. Around 20mm, I enjoy using TeleVue's 19mm Panoptic or their 20mm T5 Nagler. At 14mm and 10mm TeleVue's Delos.

[Adam Barnsley]

Can you say something about Delite 18.2mm? Don Pensack recommend this line of eyepieces to me. I don't want to undermine his knowledge, I just want to know some more opinions

[Rob Sellent]

For right or wrong, I understand DeLites as a smaller and lighter version of Delos or again, optically improved eyepieces that have filled the vacuum left by Radians.

[John]

18 hours ago, Adam Barnsley said:

it does not matter to me. How will the Dobson and focuser handle such a weight?

I have a Moonlite focuser on my scope which handles that sort of weight without a problem. I use counterbalance weight at the bottom of the tube when I'm using these heavy eyepieces except when observing towards the zenith when I take the weights off.

 

[Paul73]

I used a 1kg 21mm Ethos in my 10” SW Dob. 
No slipping issues. No real balance issues either. You can tighten up the focuser if required.

Paul

Edited December 13, 2019 by Paul73

[Timebandit]

 

 

 

 A Nice quality eyepiece around the 20mm range . Then I would have to go for the TV Nagler 20mm T5 . My goto eyepiece for DSO in the F/4.6 reflector. And works just as good in my refractor. Quality build ,sharp optics to the edge and great eye relief and fov. I purchased mine some years back second hand and have never regretted it. A quality eyepiece at sensible money ,a "Keeper" 

 

Hope this helps 

 

 

 

[niallk]

I've a 250px too - my recommendations would be:

1. 13mm Nagler T6

2. 24mm Panoptic 

[RT65CB-SWL]

Although I do not own the same 'scope as you, (SW250/f4.7), I would also go with the 13mm Nagler/Type 6.

It's the one on the right! - the other two are a 13mm Plossl (left) and a 13mm Nagler/Type 1 (centre).

Edited December 13, 2019 by Philip R

[Paul73]

At the 20mm end of things, go wide! If the pennies allow, 100°......

Or, drop back to a 24mm 82° for a similar fov to the 20mm 100°. The ES 82° 24mm works really well in your scope.

Paul

[Louis D]

2 hours ago, Timebandit said:

A Nice quality eyepiece around the 20mm range . Then I would have to go for the TV Nagler 20mm T5 . My goto eyepiece for DSO in the F/4.6 reflector. And works just as good in my refractor. Quality build ,sharp optics to the edge and great eye relief and fov. I purchased mine some years back second hand and have never regretted it. A quality eyepiece at sensible money ,a "Keeper" 

Hope this helps

Which is only available used since it was discontinued by TV in 2016 and has been sold out for some time.

[Timebandit]

13 hours ago, Louis D said:

Which is only available used since it was discontinued by TV in 2016 and has been sold out for some time.

 

The OP did not say needed to be "new " so that's why I recommended the TV Nagler 20mm T5 . I found mine used , but being a quality eyepiece then you do need to keep an eye open on the used market, and be quick to buy(as we know quality eyepiece do not hang around for sale long). But IMO then we worth the wait and space in the case, and a "Keeper" for sure. A used Ethos may be easier to locate used, but more pennies. I don't think you will go far wrong with either of the above recommendations. And buying a quality used eyepiece can save you £££ from a new purchase.

 

 

 

 

 

[John]

The Nagler 20mm T5 was in my list as well. Very sharp eyepiece and one of the most compact 2 inchers.

[Louis D]

2 hours ago, Timebandit said:

 

The OP did not say needed to be "new " so that's why I recommended the TV Nagler 20mm T5 . I found mine used , but being a quality eyepiece then you do need to keep an eye open on the used market, and be quick to buy(as we know quality eyepiece do not hang around for sale long). But IMO then we worth the wait and space in the case, and a "Keeper" for sure. A used Ethos may be easier to locate used, but more pennies. I don't think you will go far wrong with either of the above recommendations. And buying a quality used eyepiece can save you £££ from a new purchase.

 

Understood, but I got the impression the OP wanted an eyepiece in the immediate future, and I wanted to avoid disappointment on his part if he decided on a discontinued eyepiece and only then found out it has no immediate availability.  While you might have implied it is only available second hand in your original posting, you never explicitly made that clear.  I always try to recommend currently available eyepieces to relative newcomers to astronomy since waiting 6 months to a year or more for an eyepiece to become available on the used market isn't really viable for them.  What are they supposed to use in the meantime?  Of course, they could put out a wanted ad and perhaps get lucky immediately.  I've heard people wanting the 22mm Vixen LVW have had success with this approach, and perhaps it would work with the 20mm NT5.  I waited 5 years for a 22mm Nagler T4 to come up used for what I consider to be a reasonable price due to a minor cosmetic defect in the outer finish.  Until then, I continued to use my 22mm AstroTech AF70 quite happily.

[Adam Barnsley]

Thank you for your time and answers. Now I'm thinking about Nagler or Delos.

Edited December 14, 2019 by Adam Barnsley

[Adam Barnsley]

On 12/12/2019 at 20:25, Louis D said:

I tend to use powers between 75x and 100x the most often, so I would recommend getting a 12mm to 16mm

More pople said excatly same to me. So

Nagler 12mm

or

Delos 12mm

[Adam Barnsley]

Delos Have a bit smaller fov , but is more comfortable. Is Optic better(Delos) ? 

[John]

9 minutes ago, Adam Barnsley said:

Delos Have a bit smaller fov , but is more comfortable. Is Optic better(Delos) ? 

Delos came from the Ethos and the Ethos is a step up from Nagler optical performance (I moved from Naglers to Ethos a few years back). So, yes, I think the Delos will improve on the Nagler.

All these are really good eyepieces though - we are talking about margninal improvements, nothing more.