2” 50 - 60mm EP’s

[LDW47]

Anyone use / has experience using 2” 50 - 60mm eyepieces ? If so what brand and where did you buy them ? I am looking to get one just because I want one, I already have a 2” WO 40mm SWAN !

[notFritzArgelander]

The Takahashi LE series has a 50mm that is very nice but pricey.
https://www.takahashiamerica.com/takaha ... piece.html

The GSO superwides are cheaper and not so nice.
https://agenaastro.com/gso-50mm-superview-eyepiece.html

I have both. For private sessions I use the Tak. For random encounters the GSO.

The GSO is only good in slow scopes, f10. The Tak works in faster.

[avid.astronomer]

I bought a 51.5mm 2" eyepiece from the Surplus Shed (https://www.surplusshed.com/) several years ago. The eye relief produces a large "kidney bean" effect but if you can find the right distance to put your eye, it offers great widefield views of the Pleiades and the Double Cluster.

[Lady Fraktor]

Garry Russell and Harry Siebert both make good quality 2" eyepieces in the longer focal lengths
http://www.russell-optics.com/two_inch.html
https://www.siebertoptics.com/modules/eyepiecemenu.html

[DeanD]

The Takahashi LE series has a 50mm that is very nice but pricey.
https://www.takahashiamerica.com/takaha ... piece.html

The GSO superwides are cheaper and not so nice.
https://agenaastro.com/gso-50mm-superview-eyepiece.html

I have both. For private sessions I use the Tak. For random encounters the GSO.

The GSO is only good in slow scopes, f10. The Tak works in faster.

Our local Tak dealer has a single "old" model Tak LE 50 for $US280. It has been on the site for a while: see http://www.astronomy-electronics-centre ... educed.htm If you are interested it might be worth checking it out...

- Dean

[DeanD]

Garry Russell and Harry Siebert both make good quality 2" eyepieces in the longer focal lengths
http://www.russell-optics.com/two_inch.html
https://www.siebertoptics.com/modules/eyepiecemenu.html

I like the look of his stuff, and I assume Garry Russell would export to Canada, but he won't post to Australia: I tried to get one from him a while back, and he said his local post office won't send anything overseas, and the only way for him to send it to me was for him to drive 40 miles to a post office that does, (which he wasn't prepared to do) so he only deals with US clients.

I thought that was a bit weird, and rather sad...

- Dean

[LDW47]

Garry Russell and Harry Siebert both make good quality 2" eyepieces in the longer focal lengths
http://www.russell-optics.com/two_inch.html
https://www.siebertoptics.com/modules/eyepiecemenu.html

Russell Optics told me they won’t / can’t ship potside the US !

[Lady Fraktor]

Most likely because of issues between Canada/ USA customs.
Time to make friends with an American, I hear some of them are not that bad...

[LDW47]

No he said his local post office is privately contracted and they won’t / don’t handle foreign mail ! I have dealt with Canada / US Customs and the postal service hundreds of times without problems especially the USPS for my many, varied hobbies !

[Bigzmey]

I would go with 55-56mn Plossl. TeleVue if you have the funds, but Meade is good to.

[OzEclipse]

The Tak LE50 is excellent really sharp and contrasty. Narrow field - just 52 degrees.

I have seen through one in a friends Mewlon 300 and through my f9 Vixen Cassegrain.

I have a GSO 42mm. Not great compared to an LE 40 so I expect the GSO SV50 is going to give a similarly comparatively poor view.

A 50mm eyepiece will yield a 7mm exit pupil on f7 and isn't going to be effective on anything shorter.

A 60mm eyepiece will yield a 7mm exit pupil at f8.5 and isn't going to be effective on anything shorter.

Joe

[LDW47]

The Tak LE50 is excellent really sharp and contrasty. Narrow field - just 52 degrees.

I have seen through one in a friends Mewlon 300 and through my f9 Vixen Cassegrain.

I have a GSO 42mm. Not great compared to an LE 40 so I expect the GSO SV50 is going to give a similarly comparatively poor view.

A 50mm eyepiece will yield a 7mm exit pupil on f7 and isn't going to be effective on anything shorter.

A 60mm eyepiece will yield a 7mm exit pupil at f8.5 and isn't going to be effective on anything shorter.

Joe

What exactly do you mean effective ?

[OzEclipse]

The exit pupil is the diameter of the exiting shaft of light. If it is greater than the diameter of the entrance pupil to your eye, the light will not enter and you effectively have a smaller telescope. Also, the diagonal of a newtonian becomes more and more visible as a dark spot in the centre of the field of view. In any scope with a central obstruction, don't use eyepieces longer than f ratio x 7. In a refractor you don't get a central dark patch, you still lose or waste light.
Joe

[Bigzmey]

The exit pupil is the diameter of the exiting shaft of light. If it is greater than the diameter of the entrance pupil to your eye, the light will not enter and you effectively have a smaller telescope. Also, the diagonal of a newtonian becomes more and more visible as a dark spot in the centre of the field of view. In any scope with a central obstruction, don't use eyepieces longer than f ratio x 7. In a refractor you don't get a central dark patch, you still lose or waste light.
Joe

This is assuming your eye can dilate to 7mm. When we get older and for some other reasons max entrance pupil could be limited to 5-6mm.

[Lady Fraktor]

When using a refractor a oversized ExP will be wasted light and a slightly dimmer view.
Usable but not the "best" way to view.

[LDW47]

I know all about the exit pupil vs light loss vs pupil diameter, as a matter of fact the last time I had a specialist measure mine it was 5.0 or a little more but I don’t care, it does not bother my viewing I just want a 50-60mm ep, its the way I am but thanx for the info again !

[LDW47]

I accept it is what it is !

[LDW47]

My new GSO 2”, 50mm, 60°just came in from Agena Astro and its a nice looking, well built ep that I have yet to try under great skies ! Last nite I gave it a try in one of my refractors but the seeing was a wash out literally ! But stay tuned it will come !

[Bigzmey]

Congrats! Enjoy.

[Lady Fraktor]

Hopefully you will get some clear skies soon, good luck