Compromising on FOV

[Littleguy80]

Recently I’ve been pondering my eyepiece collection and how they get used. I have APM/Lunt 100 degree eyepieces and a 30mm ES 82mm. I also have a nice collection of orthos. The orthos all out perform the widefield EPs in terms of contrast and sharpness. This has led me down the path of considering eyepieces with a smaller AFOV but with better optical performance. 

Starting with the ES82 30mm, the alternative to this would be the APM UFF 30mm. I keep reading really positive reviews on this eyepiece. It’s a 70 degree AFOV but also a lot lighter. My two scopes are a 10” dob and a 80mm frac. The reduced weight would be particularly favourable with the frac. That being said, when sharing views through the big ES eyepiece, I always get a good reaction from my fellow observers. 

The next eyepiece I have is the APM HDC 20mm. I’m 100% happy with this eyepiece. It’s often used as my finder so I want to keep this focal as 100 degree. It’s performance is very good too. 

The 13mm is probably the least used of my 100 degree eyepieces. Not sure why. If money were not a consideration I would replace it with a Docter/Noblex 12.5mm, no question. The APM 84 degree 12.5mm eyepiece which is along he same lines as the Docter is getting some very positive reviews and at half the cost is quite a tempting proposition.

The final eyepiece for consideration is the 9mm Lunt XWA. This gives around a 2mm exit pupil and gets a lot of use. However, when I’m looking for something really faint it will immediately be swapped out for the 9mm BGO. The Ortho is unbeatable on this. Not sure what the options are here. 10mm Pentax XW or 9mm Nagler perhaps? 

I’d be interested to hear if anyone else has made the choice to reduce FOV to get better quality views. Is there an ideal middle ground? 

[michael.h.f.wilkinson]

I have used orthos in the past (and still have a 25mm), but what with cylindrical astigmatism, I really resent the need to push my eyeballs against the glass at the short end (I had a 5mm ortho, which I rarely if ever used due to its lack of comfort). I now have a set of Pentax XWs, and some Delos thrown in in the  gaps. These are absolutely superb, and few can see the difference in transmission and contrast between these EPs and orthos.

[John]

I thought that I might move in that direction a while back by building up a set of quality eyepieces with AFoV's of between 50 and 72 degrees. The Delos and Pentax XW's are the core of that set.

This didn't work though because I find that I still love using the hyper wides with my 12 inch dobsonian so I have kept the Ethos based set as well

What I've found is that I tend to use the smaller AFoV's with my refractors which they seem to suit well.

I can't see myself going back to using orthos again though no matter how good they are (and they are very good) 

I've given up worrying about there being eyepieces out there that are slightly better at this or that now than the ones I have. I think its possible to get a bit obsessive about that rather than fully enjoying what you do have

[jetstream]

26 minutes ago, John said:

I've given up worrying about there being eyepieces out there that are slightly better at this or that now than the ones I have. I think its possible to get a bit obsessive about that rather than fully enjoying what you do have

Thats because you have figured out the best eyepieces to use now IMHO

 

[jetstream]

1 hour ago, Littleguy80 said:

I’d be interested to hear if anyone else has made the choice to reduce FOV to get better quality views. Is there an ideal middle ground? 

The fastest, cheapest way to sort things out is to copy other experienced observers IMHO. I did this but just HAD lol! to go keep trying more and more eyepieces out.

I'll always have a 20mmish hyperwide and something around 13mm too. Supplementing the orthos wth Delos class eyepieces is a vg thing to do. Only my very best, few orthos go deeper than my Delos.

I shant ever be without orthos however, I just like them.

The 30mm ES 82 is adequate but lacking compared to the 21E/20mm APM IMHO but so is the 42mm LVW. So far I havn't found long fl eyepieces in the same class as the Ethos.

[Timebandit]

 

 

A lot of my experiences have been trial and error, finding out what my particular eyes like for the targets I am viewing. But by using more experienced astronomers successful and negative feedback on eyepieces as a bit of a guide. My particular eye's do not really feel the need for these hyper wide fov eyepiece's for the DSO targets and therefore I am more than happy with my 20mm nagler and Pentax XW for these targets. As for planetary and Luna. The Pentax XW work very well in both the reflector and refractor, and these eyepiece's  fov seem great for my eyes preference. And the Pentax XW contrast and sharpness are so Ortho like. The set of BGO I have seem to work that bit better in my refractor than the reflector . And so BGO fov and sharpness are kept mostly for refractor use on planetary and Luna. And the BGO are so good on these targets, especially when you have those brief moments on near perfect seeing conditions (for the UK ) and the Ortho really comes into its own, due to the tight fov I prefer this on planetary as it seem to draw you in more and concentrate the eye on the planetary target better. The great thing with the BGO ortho also is that I have paired some up for binoviewing on the refractor. Personally I think eyepiece's not only need to be matched to the scope, but ones eyes own preference. Eyepiece's that work for others, may not work for your eyes . As we all have are own preference, but others experience can be a great starting point for a well put together eyepiece case.

 

 

 

[Louis D]

As you probably know, I enjoy trying different eyepiece types on a given target to see which I prefer.  Sometimes, the widefield wins out, other times, it's a narrower field of view eyepiece.  There's no one perfect eyepiece for all occasions, so it's nice to have options.

[bomberbaz]

personally I have never used ortho eyepieces, so not really able to comment on this.

However I have had Delos and XW glass, I owned both these and the Nikon 17mm in my sig for a time. The Nikon 17mm replaced the 14 & 17mm Delos at the time I bought it.

 I bought the 12.5mm Nikon later  and so the remaining delos and XW went shortly after but I digress.

I found the Nikon to be as good as the delos and XW across like for like fov.  

I still love using them and imo the 17mm gives a much richer view than the nagler 26 on certain dso's.

I would relish the opportunity to compare the nikon with ethos. Sadly with the current situation that is not going to happen anytime soon.

[JTEC]

3 hours ago, Littleguy80 said:

The orthos all out perform the widefield EPs in terms of contrast and sharpness.

My experience too.  I have the, 6, 9 and 12.5 mm Taks, the last two in pairs for the binoviewer.  Other fairly simple eyepieces that are very sharp and, to my eye, deliver on those criteria, if not on all others, are some of the TV Plössls, though these look warmer to me and I like them more on lunar and planetary than deep sky.  The BGOs I used to have - though not the BCOs, which I tried and sold - were pretty much on a par, imv, with the current Taks. For resolution of critical detail, contrast and transparency, the orthos are the closest thing to a final answer in my bag and, in use, I’m likely to funnel down towards them after starting with wider fields.

But it’s not that simple.  There are so many options open to us.  We can experience the sky at multiple breadths and scales and, nowadays, all with remarkable clarity.  Spend an evening staring into M42 and, if you’re like me, you’ll experiment with different eyepieces, scoping it’s extent with one and probing its depth and detail at different scales with others. Each eyepiece will show you something different depending on field, mag and individual character. Together they build a picture that no single eyepiece can.

Some years ago I sold a small refractor and forked out for a 13mm Ethos.  It is a wonder of optical design and execution. Is it as sharp and contrasty as an ortho?  Personally, I don’t think so but it’s still remarkably so considering all else that it achieves. If I were doomed to be stuck with one eyepiece for the remainder of my observing career and the choice was between the Ethos and a 5mm ortho, it wouldn’t be difficult to decide, especially if my scope was a big push-around Dob. 👀

Personally, and based only on the eyepieces I’ve had a chance to use, I think the eyepiece that comes closest to squaring the circle is the Delos. 

Edited April 13, 2020 by JTEC

[scarp15]

Relaxed immersive eye relief transformed and became my personal approach to gradually establishing an eye piece set. This emerged when I purchased a 10mm Delos soon after they came out, my 1.25" 7mm, 9mm, 13mm naglers were sold on. The first good eyepieces I used were TeleVue plossls 11mm and 8mm, the tight eye relief, I could not imagine going back to them now, no matter how good they are (exception is 20mm and 25mm and reasonable ER). DeLite eyepieces would be my choice at a compromised field of view, used frequently in my refractor and potentially with my dobsonians. As with John's post, ultra wide field eyepieces are my preference for the dobs. 

[Don Pensack]

I'm an ultra/hyper-wide junkie, but my 2nd scope, a 4" f/7 apo, has such a short focal length, I found I could get adequately-wide true fields with 62-65° eyepieces.

So I tried a couple Delite eyepieces, thinking they might be good enough, and was simply amazed at the small pinpoint star images from edge to edge.  62° orthos, essentially, with long eye relief.

So I bought the complete set.  I wanted one lower low power, so added the APM 24mm Ultra flat field because it can accommodate glasses, which I need with focal lengths of 14mm or longer.

I previously had a 24mm Panoptic for a low power, but, alas, it's not glasses-compatible; nor was the ES equivalent.

So, did I move down in apparent field?  Yes, because I prefer 100-110° fields and treat 82° fields as "narrow" on my dob.  I would never use eyepieces narrower than, say, 70-76° in that scope, even for lunar/planetary viewing.

 

So what is the "middle ground"?  I think 70-76°--wide enough to feel immersive, sharp enough for critics, and available with long eye relief for glasses.  If you had one set for multiple scopes, that would be where I'd go.

Edited April 14, 2020 by Don Pensack

[Paul73]

Delos all the way..... (not tried the Pentax though). 72° of pint sharp stars.

Paul

 

 

[Paz]

My first good eyepiece after the plossls that come with scopes were a pair of ES82 eyepieces - 18mm and 6.7mm. I was after goof AFOV and quality but not paying TV money.

They were very good and the 6.7mm in particular saw a lot of action in many scopes but I realised that I had enough astigmatism that not using my glasses was a handicap and I also realised that it was the quality of the view not the field of view that mattered most to me so I changed tack and long eye relief became the number 1 criteria.

I went for Vixen SLV's for a light set for small scopes - the AFOV is only 50 degrees but they are small and light and worked well. Then I went for Delos for a heavier set with the Dob and they have also been great.

I don't miss very wide views, the only compromise was having a higher workload tracking objects, but I get around this with mounts. If I'm looking at fast targets near the celestial equator I use an EQ5 with an RA drive for small scopes or a tracking platform for the dob, but if I'm looking at slower targets further north I don't use motorised tracking.

[niallk]

I've never tried an ortho, but am intrigued by all the reports from experienced folk - same with Delites.  I've only looked through my own EPs, and moved from plossls to 82° Naglers and a 68° Pan24, to a set based on 17-10-6 100° Ethos.  I really like the wide field of view in my manual dob.  Hopefully I'll get to try a Delite some time at a star party.  Think I'm done purchasing EPs though

[John]

1 minute ago, niallk said:

....  Think I'm done purchasing EPs though

I think I've reached that point as well. Probably a while back really but I've had the occasional lapse since 

I have used quite a lot of orthos and they are very good in pure optical performance terms. I do prefer longer eye relief, wider field of view and a larger eye lens these days so I don't find myself reaching for my remaining ortho very much.

I think viewing comfort as a lot to be said for it, particularly using undriven, alt-az mounted scopes as I do.

 

 

 

[JamesF]

8 minutes ago, John said:

I think viewing comfort as a lot to be said for it, particularly using undriven, alt-az mounted scopes as I do.

I think it's essential.  The fewer distractions the more focused (ahem) you can be in your observing.  If you're not comfortable in your seating or standing position or don't feel completely relaxed at the eyepiece I don't think you get as much out of a session as you could.

James

[mikeDnight]

Eyepieces can be very personal things and what suits one person may not suit another. I've owned many top end wide fields, but over the last five years I've dropped them all in favour of narrower field,  but superbly transparent five element pseudo Masuyama's. I don't miss the wide field eyepieces at all, and although i really like orthoscopic's, when you get to the shorter focal lengths the eye relief can make the view uncomfortable. So, to reach high magnifications I use the Vixen High Resolution eyepieces, and so far I've not found anyother eyepiece as sharp while retaining a high level of comfort.

[John]

These were the sharpest eyepieces that I've used - a University Optics HD ortho 5mm and a TMB Supermonocentric 5mm. The latter is probably the best high power eyepiece that I have ever owned in terms of sharpness, contrast and lack of light scatter. With a 30 degree AFoV and about 2.8mm of eye relief it was hard work though. Vixen have done very well to produce their HR range that deliver excellent performance and provide 10mm of eye relief.

[johninderby]

Had 4mm and 5mm Supermonocentrics. They were great optically but the lack of eye releif made them very uncomfortable to use so soon sold them on.

Most uncomfortable eyepiece for eye releif I ever used was the Type 1 4.8mm Nager. Think it had negative eye releif. 😁 Televue says 7mm but actually about 2mm or less. My nomination for worst eyepiece of all time. Not surprisingly they are cheap to buy.

[John]

I had the 4.8 Nagler T1 as well at one point. That and the 7mm were my first Naglers. Eye relief was not a strong point I agree. The 4.8mm was very sharp though. Apparently Roland Christen used the 4.8 T1 Nagler as his principle testing eyepiece for his refractors for many years.

I didn't hate mine at all but I was happy to move to the T6 Nagler 5mm and 7mm to replace it in due course because they proved to be better eyepieces

Then the Pentax XW's and Ethos's proved to be even better .... for me at least

 

 

[bomberbaz]

20 hours ago, John said:

These were the sharpest eyepieces that I've used - a University Optics HD ortho 5mm and a TMB Supermonocentric 5mm. The latter is probably the best high power eyepiece that I have ever owned in terms of sharpness, contrast and lack of light scatter. With a 30 degree AFoV and about 2.8mm of eye relief it was hard work though. Vixen have done very well to produce their HR range that deliver excellent performance and provide 10mm of eye relief.

I hear what you say about a sharp and contrasty view but for me the lack of ER would straight away make me turn off. I was viewing the sun the other day using a 6mm generic plossl and it really wasn't fun, this was on a gti goto mount too.  I wouldn't like to use the same setup non driven. (NB: since bought a decent zoom for solar)

I am one of those who likes to sit at the eyepiece and not unduly struggle to get a comfortable position at it and just let the photons fall upon my retina without having a constant battle to centre the object in question. Maybe this makes me a lazy gazer 😄

I have taken my dob up to near 250 using the Nikon with their 102 fov and 16mm ER and still find that a pleasing experience.

[John]

1 hour ago, bomberbaz said:

I hear what you say about a sharp and contrasty view but for me the lack of ER would straight away make me turn off. I was viewing the sun the other day using a 6mm generic plossl and it really wasn't fun, this was on a gti goto mount too.  I wouldn't like to use the same setup non driven. (NB: since bought a decent zoom for solar)

I am one of those who likes to sit at the eyepiece and not unduly struggle to get a comfortable position at it and just let the photons fall upon my retina without having a constant battle to centre the object in question. Maybe this makes me a lazy gazer 😄

I have taken my dob up to near 250 using the Nikon with their 102 fov and 16mm ER and still find that a pleasing experience.

I'm the same now Steve.

I used to put up with tiny eye lenses and very short eye relief but I prefer some comfort these days.

 

[NGC 1502]

I had a 4.8mm and a 7mm type 1 Nagler.  The 7mm was no problem with eye relief without glasses.  I could also cope with the tight ER 4.8mm, however what spoiled it for me was that it would very regularly fog up, especially on cold damp nights.

Shame because otherwise it was a cracking high power EP.   The 7mm barlowed nicely for very high power occasionally.

Ed.

[JeremyS]

Having got used to using the wonderful Vixen HR series of planetary eyepieces,and  having read this thread, I thought I'd have a go with the my orthos. I have a set of Fujiyamas which are great performers. So I switched from the Vixen HR 3.4 to the Ortho 4 mm (the closest FL in the too sets; 4 mm is the shortest in the Fujiyama series, 3.4 mm is longest in the Vixen HR series). What a difference!!! I am not talking about the quality of image as that was difficult to judge as the seeing wasn't brilliant, but the ease of use. First there is the tiny eye lens in the ortho - the Vixen seems massive by contrast. There there is the need to place my eye almost on the lens. This is fine for short periods, but for longer sessions which are required to spot those fleeting moments of good seeing, the Vixen HR's win hands down. I suppose they should, though, given the price tag.

I like the Fujiyamas as the are compact and lightweight. But the Vixen's are not so different in those aspects compare to some of the short FL wide angle eyepieces. 

Can't think how I got on with that 1-inch barrel Pentax 4 mm Hi-ortho 20 years ago. Stunning performer. But not quite as good as the Pentax XP 3.8 - also in 1-inch format.

Needless to say I'm glad I bit the bullet and collected the complete set of Vixen HR's. They are a real revelation. Even the HR 1.6 mm has decent eye relief and eye lens (thanks to @mikeDnight for the nudge).

Edited April 20, 2020 by JeremyS