56 replies to this topic

[Mike B]

@ msinc:

 

The views of Saturn and then later Jupiter, once it got high enough, were the best I have ever seen. Been looking thru telescopes of all kinds since I was 11 years old.

Very pleased to hear these worked out so well for your scope & your eyes!

[penguinx64]

I had some older Starsplitter SS3 eyepieces.  Probably the best views of any of my eyepieces, but eye relief was a bit short.  I still have a Siebert 5x Barlow that's a keeper.

[izar187]

I had some older Starsplitter SS3 eyepieces.  Probably the best views of any of my eyepieces, but eye relief was a bit short.

_____________________________

 

SS3's are out of production now.

I speculate, due to component availability issues.

60º x 10mm eye relief, with eye lens right up top.

Pretty good design, going down into short focal lengths.

Definitely not eye glasses eye relief, for the whole fov at once.

But I can follow targets across the whole field, glasses on.

My 5.4 and 3.9mm SS3's easily surpass my particular barlow

combo's, with RKE's, VT orthos, plössl's and konigs,

to at or near their focal lengths. Sure, old school combo's.

[Dr Arnheim]

I just received two 2" Observatory 35mm, 72° eyepieces from Harry Siebert and had a first light with them yesterday. First of all, I have to say that Harry was super responsive and helpful with questions that I had since using 2" eyepieces in a double refractor with not much in-focus is not trivial. It is much too early for me to have a verdict on this eyepieces but I want to share my initial impressions on them and will update my experience here with time. The information can also be found in a thread on my double refractor but I want to post it here too, so that people can find it when they search for Siebert Optics. I bought them because I wanted to have eyepieces that give me the largest true field of view (4.2°) in a bino set-up (means not too wide barrels) that still give a high quality image. Since seeing and transparency was super bad last night here are my daylight observations:

 

- I like the agricultural style. They feel solid and of high quality.
- They were tack sharp over 90% of the view field and only deteriorated slightly on the last 10%.
- Distortion seems to be well controlled (I didn't see any, but have to look more critically again).
- Eye relief is large (actually a little bit too large for my liking).
- Easiness of view/immersion is not as good as with the Morpheus but close.
- I couldn't see that the afov (72°) is any smaller than the stated 76° afov of the Morpheus 17.5mm.
- One thing they don't excel at is CA control: they showed significantly more lateral CA than my Morpheus 17.5mm at half the magnification (I would say they show even more than the Morpheus 4.5mm but I have to test that). I will use them for ultra wide views of the Milky Way, so CA control is pretty meaningless for my use case but for daylight use it would bother me.

[SeattleScott]

The Morpheus 17.5 is 72 AFOV.

All the Morpheus are advertised as 76 AFOV, but none of them are actually 76 AFOV. Some are more, some are less. Perhaps Baader took sort of an average and used that for the advertised spec for the whole line. The 4.5 is one of the wider ones. Just compare how wide the view seems in the 4.5 and 17.5. The angular view should look noticeably wider in the 4.5.

It sounds like you are using these in small, relatively fast refractors. Around 600mm focal length. It would be expected that a 600mm focal length refractor would show some mild/moderate field curvature at lowest power, widest field. Did you play with the focus to see if you could make the outer 10% sharp? (At the expense of the center of the field being less sharp) The issue in the outer 10% could be primarily coming from the scopes and have little to do with the eyepieces.

Edited by SeattleScott, 17 May 2025 - 11:01 AM.

[azure1961p]

I never heard a single sour note on ANY Seibert ocular.  

 

Pete

[Dr Arnheim]

The Morpheus 17.5 is 72 AFOV.

All the Morpheus are advertised as 76 AFOV, but none of them are actually 76 AFOV. Some are more, some are less. Perhaps Baader took sort of an average and used that for the advertised spec for the whole line. The 4.5 is one of the wider ones. Just compare how wide the view seems in the 4.5 and 17.5. The angular view should look noticeably wider in the 4.5.

It sounds like you are using these in small, relatively fast refractors. Around 600mm focal length. It would be expected that a 600mm focal length refractor would show some mild/moderate field curvature at lowest power, widest field. Did you play with the focus to see if you could make the outer 10% sharp? (At the expense of the center of the field being less sharp) The issue in the outer 10% could be primarily coming from the scopes and have little to do with the eyepieces.

Yes, of course I refocused - the extend of field curvature of my Borgs is MUCH bigger than the sharpness loss of the eyepieces in the last 10% - in practical use it is a non issue. I will test more and give an update on this. I wasn't able to point the telescope on a complete even surface in a 90° angle.