Recommended a budget 1.25 eyepiece

[Nakedgun]

3 hours ago, Don Pensack said:

Well, the advice changes a lot when you know the details.

The eyepiece most likely to meet his requirements would be the Stella Lyra 24mm Ultra Flat Field:

--large eye lens

--long eye relief

--low power

--good performance/well corrected at f/5

--large field stop diameter for maximum field

--not excessively heavy

--in his price range.

~

Is this ep available under other brand names?

 

 

. 

[Louis D]

59 minutes ago, Nakedgun said:

~

Is this ep available under other brand names?

. 

As @Don Pensack pointed out in another recent thread:

• Sky Rover (China direct, Australia)
• APM (Germany)
• Tecnosky (Italy)
• Celestron (USA)
• Meade (USA)
• Altair Astro (UK)
• Stella Lyra (UK)

And I'll add Orion USA for the 24mm.  I think their version is the only one to include a thread-on 2" barrel.

[johnnyp]

@Don Pensack many thanks for the insight. The stellalyra does tick all the boxes

[johnnyp]

8 hours ago, Louis D said:

If you're only going to use 1.25" eyepiece for reasons of balance on a small scope, I'd get a quality 1.25" diagonal to further reduce the loading at the back of your scope.  A 2" diagonal adds a lot of weight in my experience with the GSO dielectric.

Any ideas on a good quality 1.25inch diagonal?. The spikes on the stellamira erect prism one I have are far too distracting.

Cheers 

John 

[Don Pensack]

Right there at FLO:

https://www.firstlightoptics.com/diagonals/stellamira-1-25-90-di-electric-diagonal.html

A prism isn't recommended with that short an f/ratio.

But the above should be excellent.

And no line/spike.

 

[Louis D]

Unless @FLO can take a picture and demonstrate that their version of the curvy neck 1.25" diagonal does NOT have a constrictive ring at the bottom of the eyepiece holder, I would err toward getting a GSO made 1.25" dielectric diagonal.  They are sold under the iOptron brand in the UK.  They don't have a constrictive ring at the bottom of the eyepiece holder.

I have a WO carbon fiber 1.25" diagonal that has the curvy neck, and it has the constrictive ring at the bottom that causes vignetting with widest field eyepieces.  Since I only use it with a 22mm clear aperture binoviewer, I'm okay with it, though.

[Mr Spock]

I had an iOptron 1.25" - the build quality was excellent.

[johnnyp]

10 hours ago, Louis D said:

Unless @FLO can take a picture and demonstrate that their version of the curvy neck 1.25" diagonal does NOT have a constrictive ring at the bottom of the eyepiece holder, I would err toward getting a GSO made 1.25" dielectric diagonal.  They are sold under the iOptron brand in the UK.  They don't have a constrictive ring at the bottom of the eyepiece holder.

I have a WO carbon fiber 1.25" diagonal that has the curvy neck, and it has the constrictive ring at the bottom that causes vignetting with widest field eyepieces.  Since I only use it with a 22mm clear aperture binoviewer, I'm okay with it, though.

I believe it does as you say, have the ring at the bottom. I know the WO does as i've had one previously.  I am specifically looking for one without the ring, so thanks for your suggestion. I think i've seen that particular diagonal on rother valley optics. I'd like to try a prism like the tak or the baader T2, but i think i'd have problems with focus on my 72ed.

Cheers

John

[johnnyp]

13 hours ago, Mr Spock said:

I had an iOptron 1.25" - the build quality was excellent.

@Mr Spockis the eyepiece retaining screw on the bottom of the holder (as per the stock image ) or can the holder be rotated ? 

[Don Pensack]

3 hours ago, johnnyp said:

I believe it does as you say, have the ring at the bottom. I know the WO does as i've had one previously.  I am specifically looking for one without the ring, so thanks for your suggestion. I think i've seen that particular diagonal on rother valley optics. I'd like to try a prism like the tak or the baader T2, but i think i'd have problems with focus on my 72ed.

Cheers

John

The GSO is a good suggestion, too.

I don't advise the use of prisms if the scope is faster than f/8 due to the chromatic aberration you'd likely see.

[Don Pensack]

30 minutes ago, johnnyp said:

@Mr Spockis the eyepiece retaining screw on the bottom of the holder (as per the stock image ) or can the holder be rotated ? 

The iOptron star diagonal appears to be a rebranded GSO star diagonal, which would not be a bad thing.

If so, and I think it likely, the thumbscrews vary in position somewhat from unit to unit.

Look for the dielectric coatings to keep light transmission high.  72mm is not a lot of aperture and needs all the help it can get.

 

[Louis D]

1 hour ago, johnnyp said:

@Mr Spockis the eyepiece retaining screw on the bottom of the holder (as per the stock image ) or can the holder be rotated ? 

I doubt if the holder can be rotated as that would probably unscrew it.

[LDW1]

On 10/12/2022 at 11:42, johnnyp said:

I recently acquired a 2inch diagonal and a Skywatcher 28mm let eyepiece. Having never used a 2inch eyepiece before, I have fallen in love with the big eye glass on the let. 

I prefer 1.25inch accessories though as my scope balances better with them. Any thoughts on a low power 1.25 with big eye glass and pleasing views ?...I'm not exactly spoiled with the Skywatcher let so I'm easily pleased.

Budget up to around £150

Many thanks 

John 

 

Try one of the Svbony zooms for a bit of fun, a change of pace at a great price, I have 3 that I play with and I love them with solar viewing.

[Louis D]

3 minutes ago, LDW1 said:

Try one of the Svbony zooms for a bit of fun, a change of pace at a great price, I have 3 that I play with and I love them with solar viewing.

Do any of them have a big eye lens for relaxed viewing as put forth by the OP?  I've read that the APM SuperZoom has good eye relief due to a largish eye lens, but I'm not sure about the Svbony zooms.

[LDW1]

14 minutes ago, Louis D said:

Do any of them have a big eye lens for relaxed viewing as put forth by the OP?  I've read that the APM SuperZoom has good eye relief due to a largish eye lens, but I'm not sure about the Svbony zooms.

Relaxed ?  Throw in the cost comparison along with a relaxed view, to my eyes the views in any of mine are great. What does relaxed mean, not having to squint or blink or what ?  Sometimes they make me so relaxed that I almost fall asleep zooming in and out without having to change eps, lol ! Now thats relaxed !

Edited December 12, 2022 by LDW1

[Louis D]

5 minutes ago, LDW1 said:

Relaxed ?  Throw in the cost comparison along with a relaxed view, to my eyes the views in any of mine are great. What does relaxed mean, not having to squint or blink or what ?  Sometimes they make me so relaxed that I almost fall asleep zooming in and out without having to change eps, lol ! Now thats relaxed !

Don't ask me, ask the OP why he has "fallen in love with the big eye glass on the let".  I've assumed it has to do with the relaxed view from longer eye relief that doesn't require mashing your eye into the eye cup to see the entire field of view.

I know I can barely use my 7.2-21.5mm zoom due to its small eye lens (16mm diameter) and tight eye relief (9mm - 11mm) even without eyeglasses.  My eyelashes keep brushing the top of the eyepiece whenever I blink.  With eyeglasses, it's like looking through a soda straw.  Without eyeglasses, my 2.5 diopters of astigmatism make for spiky star images.

Also, the zoom action is so stiff that I have use two hands to zoom.  Are the Svbony zooms' zoom actions silky smooth enough as to require only fingertip pressure?

[Mr Spock]

2 hours ago, johnnyp said:

is the eyepiece retaining screw on the bottom of the holder (as per the stock image ) or can the holder be rotated ? 

Here's the one I had.

[johnnyp]

8 minutes ago, Louis D said:

Don't ask me, ask the OP why he has "fallen in love with the big eye glass on the let".  I've assumed it has to do with the relaxed view from longer eye relief that doesn't require mashing your eye into the eye cup to see the entire field of view.

I know I can barely use my 7.2-21.5mm zoom due to its small eye lens (16mm diameter) and tight eye relief (9mm - 11mm) even without eyeglasses.  My eyelashes keep brushing the top of the eyepiece whenever I blink.  With eyeglasses, it's like looking through a soda straw.  Without eyeglasses, my 2.5 diopters of astigmatism make for spiky star images.

Also, the zoom action is so stiff that I have use two hands to zoom.  Are the Svbony zooms' zoom actions silky smooth enough as to require only fingertip pressure?

Yeah I think it is the eye relief that makes it feel "relaxed " 

[johnnyp]

8 minutes ago, Mr Spock said:

Here's the one I had.

Does seem like the position of the thumbscrew varies from unit to unit. Thanks for that

[LDW1]

13 minutes ago, Louis D said:

Don't ask me, ask the OP why he has "fallen in love with the big eye glass on the let".  I've assumed it has to do with the relaxed view from longer eye relief that doesn't require mashing your eye into the eye cup to see the entire field of view.

I know I can barely use my 7.2-21.5mm zoom due to its small eye lens (16mm diameter) and tight eye relief (9mm - 11mm) even without eyeglasses.  My eyelashes keep brushing the top of the eyepiece whenever I blink.  With eyeglasses, it's like looking through a soda straw.  Without eyeglasses, my 2.5 diopters of astigmatism make for spiky star images.

Also, the zoom action is so stiff that I have use two hands to zoom.  Are the Svbony zooms' zoom actions silky smooth enough as to require only fingertip pressure?

Thats your eyes doing the brushing but maybe not the OP's and in -15C they are silky smooth but many are too afraid to tighten them down a bit for fear of marking the barrel. I have owned about 7-8 zooms and not one has been resistent to easy turning. It appeared the OP wanted options all I did was give them a good one.

Edited December 12, 2022 by LDW1

[LDW1]

10 minutes ago, johnnyp said:

Does seem like the position of the thumbscrew varies from unit to unit. Thanks for that

This Celestron dielectric is an excellent performer but its on the expensive side.

[Ricochet]

I own a 72ED and an Altair Starwave Mini mount, which I believe to be the same as the AZT6, although I have now upgraded to a Scopetech Zero. For a diagonal I usually use a Baader BBHS prism with a 1.25"-2" clicklock reducer for the clamp, a 2" T2 nose and two T2 extensions (15 and 7.5mm?) which weighs in a 328g. Despite the f6 focal ratio I see no issues with prism induced CA and I believe that the image is sharper than with a mirror diagonal. I tend to use three eyepieces: a 3-6 Nagler Zoom weighing 150g, a 13 Delite at 222g and a 24 Panoptic at 232g. I also own Pentax XWs, the lightest of which is the 14XW at 372g, but due to the difference in weight I never use these eyepieces with the 72ED. I've just tried the 14XW and the Starwave Mini definitely struggles more with it than it does with a 13 Delite. The suggestion of a 24mm UFF is generally a great suggestion but the listed weight is 330g so perhaps for this particular setup it might be a touch on the large side. A more lightweight alternative would be the 26mm ES62° which weighs in a 235g, basically the same as the 24 Panoptic that I use. However, I don't know how well this eyepiece will perform at f6 and I am fairly sure that the UFF will be better optically at all focal ratios.

[Louis D]

59 minutes ago, Ricochet said:

A more lightweight alternative would be the 26mm ES62° which weighs in a 235g, basically the same as the 24 Panoptic that I use. However, I don't know how well this eyepiece will perform at f6 and I am fairly sure that the UFF will be better optically at all focal ratios.

The general consensus is that JOC reissued the Meade 5000 Plossl series as the ES-62 series since the specs and focal lengths are so similar.  If that is the case, I can speak to the 40mm focal length since I own the Meade 5000 Plossl version.  It is super sharp in the inner 50% at f/6 and then rapidly fuzzes out moving to the field stop due to astigmatism.  On the plus side, the moon doesn't distort much at all moved from center to edge.

The design is basically a variation on the Zeiss Astroplan opened up to 60/62 degrees.  Even if it had been limited to 50 degrees, their design would still have had edge issues since that would only eliminate the outer 17% or so.  Normally, these Astroplan variations are sharp to the edge at f/6 over a 50 degree AFOV as with the old Celestron Ultima, Parks Gold, Orion Ultrascopic, and Baader Eudiascopic "Plossls".

The view through the 40mm Meade 5000 Plossl in my field flattened 72ED is shown below relative to others.  Since it is a scaled design, all of the other focal lengths except for the 5.5mm, which has 6 elements, should perform similarly.

[Ricochet]

Thanks, Louis. I should have known you'd have something from that line.

[great_bear]

23 hours ago, Louis D said:

The general consensus is that JOC reissued the Meade 5000 Plossl series as the ES-62 series since the specs and focal lengths are so similar.  If that is the case, I can speak to the 40mm focal length since I own the Meade 5000 Plossl version.  It is super sharp in the inner 50% at f/6 and then rapidly fuzzes out moving to the field stop due to astigmatism.  On the plus side, the moon doesn't distort much at all moved from center to edge.

The design is basically a variation on the Zeiss Astroplan opened up to 60/62 degrees.  Even if it had been limited to 50 degrees, their design would still have had edge issues since that would only eliminate the outer 17% or so.  Normally, these Astroplan variations are sharp to the edge at f/6 over a 50 degree AFOV as with the old Celestron Ultima, Parks Gold, Orion Ultrascopic, and Baader Eudiascopic "Plossls".

The view through the 40mm Meade 5000 Plossl in my field flattened 72ED is shown below relative to others.  Since it is a scaled design, all of the other focal lengths except for the 5.5mm, which has 6 elements, should perform similarly.

I took a S5000 Plossl apart (not the 40) and it wasn’t like that at all on the inside. Are you going by documentation or have you taken a look yourself? 
 

Mine was basically an Erfle variant. 
 

The 26mm would be a mess at F6. It wasn’t that great at F15 to be honest. 
 

However, apart from minor eye-glint, the 20mm and 14mm are essentially perfect in an F15 Mak - I wouldn’t swap them for anything. The glass has a breathtaking coolness to it. I’ve used mine in a WO Binoviewer for several years now, and nothing has beaten them. 
 

interesting to hear they’re back in production. I saw that range and wondered if those might be them redesigned.