12 replies to this topic

[has530]

I have a celestron hummingbird micro-spotting scope which I am trying to get a good fixed eyepiece for. I want something in the 7-9mm range as that puts me at 22-28x and it would be my preference to have an exit pupil of at least 2mm. So far I have tried the 8mm paradigm which had too much kidney beaning for daytime use, the SVBONY redline 9mm which also had tricky eye placement and poor color correction on high-contrast targets, the 9mm BST 58 which had a bright rainbow ring around the field stop, and the 7 and 9mm x-cels which both had a lot of stray light scatter and very sensitive to eye placement. I am wondering if anyone has any suggestions for a well corrected eyepiece with a 60-72 degree FOV and easy pupil placement. I don't need perfect edge correction as at f/3.6 that would be an expensive demand but I also want good center sharpness and contrast. I am considering the 8mm hyperion as I have the 13mm that does okish at f/3.6 it and it has easy eye placement, the 9mm delite but it is a little pricey for what I was hoping for, the orion 8mm flat but I would prefer more eye relief, maybe the ES 62 9mm? Is there something good out there I haven't considered? Does anyone have experience with these in fast scopes? Any opinions would be appreciated.

[luxo II]

No eyepieces do particularly well below f/4.5.

At f/3.6 you're asking for something that doesn't exist.

 

If you really valued image quality above all else you should choose a slower scope to suit the eyepieces. This is why mine are f/12.

Edited by luxo II, 25 March 2025 - 01:51 AM.

[eblanken]

Hello (aka has530),

 

I confess that I'm very spoiled by my set of Televue DeLites and would highly recommend the 7mm or the 9mm to you. Sorry for the hit that either would put to your budget. Either would do well for you.

 

Tell us if you need corrective eyeglasses (ie. what Eye Relief do you need ?) ? For Astigmatism ?

 

I also own all the Baader Hyperions. They are going to get "beat up" by many as not suitable for your fast OTA at f/3.6. Additionally, to get the wider Apparent Field of View of 68 Deg. as compared to the DeLites at 62 Deg. AFoV, the eye lens of the Baader has to be bigger, so the whole eyepiece is bigger and heavier as you have experienced with the 13mm Hyperion that you have in hand. Is it too big and too heavy or not ?

 

I also own the Pentax XW 68 Deg. Set as well, but these are big also just like the Hyperion, so same considerations apply.

 

So please hunt for a DeLite at 7mm or 9mm on the used market ? Also, a used 8mm Radian might work, but 57 Deg.AFoV might not quite cut it for you even if the price was palatable ?

 

How do you feel about Barlows ? A 2x Barlow and a 18mm to 14mm would be f/3.6 TIMES 2x for the result of f/7.2, so how does that feel ? Even a 1.5x would get your f/3.6 into a slower position of f/5.4 and that could be achieved with just the lens cell of a 2x Barlow that can unscrew from the Barlow's Body (If that appeals to you, speak up and I can try to get you a link).

 

Sorry to say it, but you picked a tough corner to position yourself into . . .

 

Low Price, Wide AFoV, Fast OTA: Pick two and give in some on the third . . . 

 

Best,

 

Ed

Edited by eblanken, 25 March 2025 - 02:11 AM.

[eblanken]

No eyepieces do particularly well below f/4.5.

At f/3.6 you're asking for something that doesn't exist.

 

If you really valued image quality above all else you should choose a slower scope to suit the eyepieces. This is why mine are f/12.

 

+1 on the harsh reality of what luxo II says . . . 

 

Ed

[Jon Isaacs]

+1 on the harsh reality of what luxo II says . . . 

 

Ed

 

People are using Ethos's, Delos and other TeleVue eyepieces in fast Newtonians.  Mel Bartels has a 24 inch F/2.6 that's F/3.0 with a Paracorr 2.  He designed the scope around the 21mm Ethos.

 

A Delos could be a good choice.  I think a 9mm Type 6 Nagler should be sharp at F/3.6 assuming the field curvature of the 200 mm objective is not a problem.  

 

Eyepieces that are well corrected at F/3.6 exist but they will cost more than the scope.  

 

Jon

[SeattleScott]

Do you know the Xcel LX have adjustable height eyecup to help with eye position? If don’t wear glasses, you should raise the eyecup.

The Xcel LXs are the cream of the crop of the eyepieces you have so far. The fact that eye position got easier as it got darker is the simple realistic that eye position gets easier as your pupil dilates wider. Terrestrial viewing is hard. But again, raising the eyecup can help here. Both the 7 (really 6.5) and the 9 tested quite well at F4. Ernest recommended them, with their great edge correction, easy eye placement and noted that stray light was within acceptable limits (in other words, about as good as it gets without spending $300). Your issues with the Xcel LXs weren’t edge correction so much as eye position and a lot of stray light. Adjusting the eyecup can help with eye position. The stray light control is pretty good for an affordable eyepiece. To do better, expect to spend around $300.

I am guessing this scope is a pretty small thing and a Delos might seem like a bit of a boat anchor. I can attest that Nikon SW performs great at F4 (as can Ernest) although it probably won’t be perfect at F3.6. It will be as good at the edges as the Xcel LX with easy eye placement and 72 AFOV with great stray light control. The Nikon also has desirable distortion characteristics for terrestrial viewing, Delite is even lighter, similar performance at F4. A Delos will have the best edge correction. It is just heavy and even more expensive, and the distortion characteristics are better for astronomy than terrestrial.

Ultimately the two Xcel LXs you have are outstanding performers for the price. If they aren’t cutting it for you, you need to step up to $300 eyepieces. Do you want to spend that much for spotting scope eyepieces? Or get a different spotting scope?
The ES 62 is only a five element eyepiece and not suitable for such a fast F ratio.

Edited by SeattleScott, 25 March 2025 - 05:36 AM.

[25585]

A Vixen SLV is small and light, with adjustable eye height. They are very sharp and might do well. Lots of focal lengths to try.

[CrazyPanda]

No eyepieces do particularly well below f/4.5.

At f/3.6 you're asking for something that doesn't exist.

 

If you really valued image quality above all else you should choose a slower scope to suit the eyepieces. This is why mine are f/12.

Tele Vue eyepieces do just fine below F/3, let alone F/4. Saying you need F/12 to get good views is silly.

 

The issue OP is going to run into is he has a short focal length refractor and field curvature is going to be the dominant issue when it comes to edge quality. There's no fixing that short of getting lucky and finding an eyepiece whose own curvature profile matche's the scopes. There's no way to attach a field flattener to it as far as I know.

 

Still, the best performers are going to be premium widefields (Tele Vue, Nikon, Pentax). When I was auditioning eyepieces for my 60mm F/3.75 finder scope, the best performers were Tele Vue DeLites. Field curvature was still noticeable but I could mostly accommodate it.

 

 

 

Does anyone have experience with these in fast scopes? Any opinions would be appreciated.

 

OP, no experience with that scope in particular, but as I mentioned earlier, I tested a variety of eyepieces in my 60mm F/3.75 finder scope which will have similar behavior to your hummingbird spotter. Tele Vue DeLites were the best. The flat, ~62 degree field minimized field curvature visibility and the edge correction was perfect. Yes, it's spendy, but if you're favoring optical quality, DeLites are the way to go. There is no kidney beaning and no off-axis glare since DeLites are very well baffled, but you do have to make sure you adjust the eye guard to the right height to avoid blackouts.

Edited by CrazyPanda, 25 March 2025 - 06:59 AM.

[SeattleScott]

To me, yes, if the OP wants better performance than the Xcel LXs, they need to look at $300 eyepieces. But because of the baffling and light suppression, not edge correction. They understand and accept that the edges won’t be perfect. They seem happy enough with the edge correction of the Xcel LXs. Their complaints are eye placement and glare. Eye placement is just an issue of terrestrial viewing and not knowing how to use an adjustable height eyecup. Some practice will fix that. It isn’t like Xcel LXs struggle with eye placement. But if someone wants eyepieces as easy to use in the day as at night, that’s probably not happening. It is the glare issue that drives the need for premium glass. The Xcel LX are pretty well blackened/baffled for affordable eyepieces. To do any better, you need a premium brand. To me, that’s the driver. They are ok with less than perfect edges as long as the center is as sharp and contrasty as possible. Which means premium glass.

The OP said the 13 Hyperion works ok-ish. We know the 13 Hyperion is particularly poor at F3.6. So to me it isn’t really about edge correction.

The Nikons are smallish and contrasty with great edge correction, and have good distortion characteristics for terrestrial. The Delites are even smaller, and at just 62 AFOV, the distortion characteristics should be ok for terrestrial. Both have adjustable height eyecups. Both are regarded as easy to view through. These are the obvious contenders if the OP is willing to spend $300 on eyepieces for a $350 spotting scope. If not, the Xcel LXs are as good as it will get.

[eblanken]

+1 on what Scott said , , , 

 

Ed

[has530]

Yes I don't care too much about edge correction. I use a lot of old 7x35 10-12 degree binos which are pretty bad at the edge so I am used to just using the edges for object finding then enjoying the center field. I do not need glasses but I do need about 12mm of ER thanks to my long eyelashes. Maybe I should give the X-cel another go. I may have just had lemons as both had visible bubbles in the glass so I would imagine most of the poor contrast was from light scatter in the shoddy glass. I had no problems with the eyecups and actually rather liked them. The tricky eye placement I think was rather catching stray light from outside the exit pupil and the extreme sensitivity to lateral color in the eye placement (very little with perfect centering but just a little off it was pretty bad).

 

I also tried a barlow but couldn't get any eyepieces to come to focus even with a shorty threaded on to the eyepiece.

 

A little less expensive than the delite...has anyone tried the Siebert SS4 7.9mm? Looks like it would fit the bill but have never tried anything from them. I am also not opposed to bigger EPs like the XWs but am worried about getting focus as my 10.5 XL juuuuuust barely doesn't reach focus at infinity (I can kind of get there with my visual accomidation but it is not comfortable).

[SeattleScott]

Unfortunately Xcel LX do have a sketchy reputation for QC. If you get good ones, the 7 and 9 are fantastic values. But it can be hard to get good ones.

The size of the eyepiece has nothing to do with the focus position. I believe XLs focus at the shoulder (at least their cousin XWs do). So this might rule out eyepieces that focus at the shoulder, like Pentax, Nikon, Morpheus, etc. Televue would work fine, and likely ES, Meade.

[GGK]

Delos and Delite eyepieces are excellent in my f/4 flat field refractors. I have no experience below that focal ratio.

Gary