31mm Nagler/Antares 1.6x barlow?

[casstony]

The new Nagler arrived yesterday and it looks like being cloudy for a few days so I can only play with it in the daytime. It seems to work well with the barlow but I'm curious to hear from someone who's used this combo under the stars. Is there any negative impact on the image from using the 31 Nagler with the 1.6x barlow?

[blink138 (Pat)]

nothing really negative except that a 20mm eyepiece will give the same magnification with less glass to air surfaces (i think)
pat

[JethroB76 (Jeff)]

Have you got an Antares or considering one?
Haven't used one with the 31T5 but it works well with my Ethoses and 20T5

*edit* nvm, looks like you've got one and used it in daylight..

[ausastronomer (John Bambury)]

Originally Posted by casstony

The new Nagler arrived yesterday and it looks like being cloudy for a few days so I can only play with it in the daytime. It seems to work well with the barlow but I'm curious to hear from someone who's used this combo under the stars. Is there any negative impact on the image from using the 31 Nagler with the 1.6x barlow?

Hi Tony,

I have both of those items and they work very well together in my F4.5 newtonians. That having been said I only use that combo to "play around and test". While it has a larger TFOV, optically it is just short of the 20mm Pentax XW in a paracorr in those scopes, in terms of contrast and throughput. Slightly better at EOF, a little behind on axis. It comes down to personal preference and what performance criteria are most importnat to you.

If you don't already own an 18mm to 22mm eyepiece, the 31mm Nagler in the 1.6X Antares is an excellent option and saves the need to buy another eyepiece. Any gain from a standalone 20mm eyepiece isnt huge. And it does give very good eye relief at this focal length.

Cheers,
John B

[casstony]

If it works well, apart from getting dual use out of an expensive eyepiece, there is no other 20mm eyepiece which can equal the 80 degree, sharp to edge field with decent eye relief.

Nagler 22mm doesn't have the edge performance, Nagler 20mm and Ethos 21mm don't have the eye relief.

Edit: thanks John, saw your post after I hit the submit button. Good to hear it works well. It'll be used in my 6" f/5 achro with and without the barlow and in the C11.

[ausastronomer (John Bambury)]

Originally Posted by casstony

Nagler 22mm doesn't have the edge performance

Hi Tony,

The edge performance of the 22mm Nagler improves immeasurably in a paracorr, which brings it down almost to 20mm. The 17mm Nagler is another eyepiece which really needs a paracorr to do its best. Without a paracorr both arent great in a fast scope IMO. With the paracorr they are very good and have good comfort and eye relief. However, they offer no improvent over the barlowed 31mm IMO.

Cheers,
John B