Wearing glasses and eyepieces

[John]

Just a friendly tip 🙂 - you might want to start new threads for some of these queries. Tagging them onto an existing thread can limit the amount of responses you get.

Plus some of them are quite complex topics in their own right.

Edited October 6, 2023 by John

[bosun21]

22 hours ago, Coolhand1988 said:

Also I think the 17.5mm version has either been misquoted or it's been redesign.

The 17.5mm was released several years later than the others in the range. It’s never been redesigned and in my opinion it’s the best of them all (by a whisker) The others are also excellent eyepieces and are the mainstay of my observing.

[Coolhand1988]

3 hours ago, John said:

I feel that using a 2 inch diagonal with a 1.25 inch adapter is the best approach. Less expense and hassle as well. 

 

That's what I was thinking.  It seems the best approach.

3 hours ago, John said:

Just a friendly tip 🙂 - you might want to start new threads for some of these queries. Tagging them onto an existing thread can limit the amount of responses you get.

Plus some of them are quite complex topics in their own right.

Good point. Guess I did not want to start newer threads. 

Referring to post 3 of this thread?  With my eye floaters, a 4mm EP in an F8 scope is the smallest FL to ( hopefully ) view comfortable with an exit pupil of 0.5mm?

Thanks

 

[Coolhand1988]

1 hour ago, bosun21 said:

The 17.5mm was released several years later than the others in the range. It’s never been redesigned and in my opinion it’s the best of them all (by a whisker) The others are also excellent eyepieces and are the mainstay of my observing.

Thanks. I'm hoping to get this range of eyepieces for the good eye relief as I wear glasses.

So that 2023 spreadsheet has a few errors for the 17.5mm version. And according to the Baader website, this eyepiece is slightly off for parfocal, to the rest of this range. 

Just getting all the facts before I buy.

Thanks

[Ricochet]

24 minutes ago, Coolhand1988 said:

Referring to post 3 of this thread?  With my eye floaters, a 4mm EP in an F8 scope is the smallest FL to ( hopefully ) view comfortable with an exit pupil of 0.5mm?

Floaters do not depend on eyepiece focal length but on exit pupil. A 4mm eyepiece will tend to show floaters because it is unusual to have a scope with a focal ratio less than f4 so the exit pupil will tend to be 1mm or less. When floaters become a problem will vary from person to person (eye to eye even) so you will need to find when they become problematic for you by experimentation. Floaters are usually only a problem with bright objects, so lunar and planetary, and a 0.5mm exit pupil will tend to be too much for these objects. 

[Coolhand1988]

20 minutes ago, Ricochet said:

Floaters do not depend on eyepiece focal length but on exit pupil. A 4mm eyepiece will tend to show floaters because it is unusual to have a scope with a focal ratio less than f4 so the exit pupil will tend to be 1mm or less. When floaters become a problem will vary from person to person (eye to eye even) so you will need to find when they become problematic for you by experimentation. Floaters are usually only a problem with bright objects, so lunar and planetary, and a 0.5mm exit pupil will tend to be too much for these objects. 

Thanks. I was reading a guide on eyepieces and must of had brain overload on my part.  

I understand eye floaters can vary from person to person. I was trying to get a rough understanding on exit pupil size of the eyepiece, where floaters becomes unbearable.

Thanks

[John]

I have some floaters but find that they are only an issue when observing targets which are large and quite bright, eg: the lunar surface. 

I use eyepieces down to 3mm or sometimes even 2.5mm focal length which give exit pupils as small as .4mm in my scopes.

For deep sky observing, double stars and planetary observing they are generally not an issue. 

Edited October 6, 2023 by John

[Coolhand1988]

1 hour ago, John said:

I have some floaters but find that they are only an issue when observing targets which are large and quite bright, eg: the lunar surface. 

I use eyepieces down to 3mm or sometimes even 2.5mm focal length which give exit pupils as small as .4mm in my scopes.

For deep sky observing, double stars and planetary observing they are generally not an issue. 

Many thanks. It good to hear other observers experience with floaters and different eyepieces on DSO, lunar, etc. One or two of my floaters are also visible in dim light.

Have to test this properly very soon.

Thanks

[Louis D]

The only reason I've found to use a 1.25" diagonal over a 2" diagonal in a 2" or larger focuser is due to lack of back/in focus with the scope or usage.  This is common with Takahashi refractors in particular.  It also crops up with binoviewers.  The latter need at least 100mm of back/in focus due to their optical path length.  2" diagonals require about 40mm more back/in focus than a 1.25" diagonal for the same reason.  Combine them, and now need 140mm of additional back/in focus exacerbating the problem when using BVs.

Most non-Tak refractors tend to be designed for use with 2" diagonals for monoviewing.  A few refractors have removable section(s) for native binoviewer usage.  Check specifications before buying to see if the scope will meet your needs.

[Stu]

On 04/10/2023 at 23:26, Coolhand1988 said:

Hi

Thanks for that, I was unsure what focal length eyepieces could cause this.

Binovewiers it is then!  But I will try just viewing with one eyepiece to get a feel for the floaters. I then should know what double FL eyepieces to get for binoviewing.

I have read that once you go Bino's, there is no way back to single viewing again. Is that true?

Thanks

Floater visibility depends on exit pupil, not on eyepiece focal length.

The exit pupil is the diameter of the beam of light entering your pupil, and is calculated by dividing the aperture of the scope by the magnification being used, or aperture * focal length of eyepiece / focal length of scope.

Take two extremes:

A 4mm eyepiece in a 60mm f15 (900mm focal length) refractor scope gives an exit pupil of 0.26mm and a mag of x225

A 4mm eyepiece in a 500mm f4 (2000mm focal length) dobsonian gives an exit pupil of 1mm and a mag of x500

Floaters tend to start being more visible under 1mm and get intrusive below 0.5mm, so the 60mm scope view would be very dark with lots of floaters, the 500mm would be brighter with few or now floaters despite the higher mag.

I suffer from floaters so do use binoviewers for high power lunar and Solar viewing in my refractors. I don’t need them in my 8” or above scopes, and don’t use them for low or medium power views as I prefer a single eyepiece for that.

I may have missed it, but I’m not sure what sort of scope you will be using? Depending on this, you may have to use better quality eyepieces of be able to get away with cheaper ones. Faster scopes eg below about f5 need better quality eyepieces to keep the edge performance acceptable. Televue eyepieces are designed to work down to f4 which is part of the reason for their greater cost.

Also mentioned is that if you don’t have strong astigmatism, you may get away without glasses at all which helps.

[Coolhand1988]

12 hours ago, Louis D said:

The only reason I've found to use a 1.25" diagonal over a 2" diagonal in a 2" or larger focuser is due to lack of back/in focus with the scope or usage.  This is common with Takahashi refractors in particular.  It also crops up with binoviewers.  The latter need at least 100mm of back/in focus due to their optical path length.  2" diagonals require about 40mm more back/in focus than a 1.25" diagonal for the same reason.  Combine them, and now need 140mm of additional back/in focus exacerbating the problem when using BVs.

Most non-Tak refractors tend to be designed for use with 2" diagonals for monoviewing.  A few refractors have removable section(s) for native binoviewer usage.  Check specifications before buying to see if the scope will meet your needs.

Yes I've been reading up on this. A 2" diagonal needs more backfocus, however if the diagonal is a prism type,  there should be no additional backfocus compared to a mirror type.

I've also seen some scopes have a detachable tube extension to make BV more friendly for mirror type diagonals.

Decisions decisions!

Thanks

 

[Coolhand1988]

5 hours ago, Stu said:

Floater visibility depends on exit pupil, not on eyepiece focal length.

The exit pupil is the diameter of the beam of light entering your pupil, and is calculated by dividing the aperture of the scope by the magnification being used, or aperture * focal length of eyepiece / focal length of scope.

Take two extremes:

A 4mm eyepiece in a 60mm f15 (900mm focal length) refractor scope gives an exit pupil of 0.26mm and a mag of x225

A 4mm eyepiece in a 500mm f4 (2000mm focal length) dobsonian gives an exit pupil of 1mm and a mag of x500

Floaters tend to start being more visible under 1mm and get intrusive below 0.5mm, so the 60mm scope view would be very dark with lots of floaters, the 500mm would be brighter with few or now floaters despite the higher mag.

I suffer from floaters so do use binoviewers for high power lunar and Solar viewing in my refractors. I don’t need them in my 8” or above scopes, and don’t use them for low or medium power views as I prefer a single eyepiece for that.

I may have missed it, but I’m not sure what sort of scope you will be using? Depending on this, you may have to use better quality eyepieces of be able to get away with cheaper ones. Faster scopes eg below about f5 need better quality eyepieces to keep the edge performance acceptable. Televue eyepieces are designed to work down to f4 which is part of the reason for their greater cost.

Also mentioned is that if you don’t have strong astigmatism, you may get away without glasses at all which helps.

Thanks for that information.

I plan to use a 5 to 6 inch EDT or ED F7/8 refractor and a F/10 8 inch or higher SCT. 

Eyepieces will be the Baader Morpheus range and looking at couple of Televue panoptics with medium to long focal lengths. However if my budget permits, the Delos EPs would be my next option instead of the baaders.

My astigmatism is low at 0.25/10d in my right eye only. The TV Dioptrx corrector sounds very good if I decide not to wear glasses, but it will be a worthwhile item for my collection.

Thanks

[dweller25]

On 04/10/2023 at 22:42, Coolhand1988 said:

Doing some research, it appears eyepieces with an eye relief of 20mm or more is best suited, but was wondering from members If there is a lower distance that is highly acceptable?

I wear varifocals when observing and have found 15mm eye relief to be the lowest I can go (18mm Orthos), around 20mm eye relief I find is more comfortable.

[Coolhand1988]

33 minutes ago, dweller25 said:

I wear varifocals when observing and have found 15mm eye relief to be the lowest I can go (18mm Orthos), around 20mm eye relief I find is more comfortable.

Varifocals will be my next pair. I have around a 2 foot viewing distance where my bifocals are out of focus on both lens. It's good you can go lower than 20mm for your eye relief. The smaller FL of the Baader Morpheus EPs, are indeed lower than 20mm.

Thanks

Edited October 7, 2023 by Coolhand1988
Clarity

[DeanCJ]

Although not a wide field eyepiece, have you considered the Vixen SLV range? Myself I quite like the 50° view,especially for lunar and planetary.
https://www.firstlightoptics.com/vixen-eyepieces/vixen-slv-eyepieces.html              
Each focal length has a quoted eye relief of 20mm. 
I have SLV’s from 9 to 25mm and although I have never viewed through a top tier eyepiece I do find that for the price, the SLV’s are very nice, and not too expensive. If you shop around they can be found second hand at a very reasonable price.

[Coolhand1988]

51 minutes ago, DeanCJ said:

Although not a wide field eyepiece, have you considered the Vixen SLV range? Myself I quite like the 50° view,especially for lunar and planetary.
https://www.firstlightoptics.com/vixen-eyepieces/vixen-slv-eyepieces.html              
Each focal length has a quoted eye relief of 20mm. 
I have SLV’s from 9 to 25mm and although I have never viewed through a top tier eyepiece I do find that for the price, the SLV’s are very nice, and not too expensive. If you shop around they can be found second hand at a very reasonable price.

These indeed look very nice and glasses friendly as welI. I like the adjustable eyecups, unsure if that is a unique design for these eyepieces?

I was trying to stick to one or two brands and a higher AFOV, which is why I failed to look at any 50 FOV EPs.

My very first and now old EPs had a narrow FOV between 40 and 50 and I always wanted a much higher FOV for newer EPs.

I wonder if the 'old hand' observers still stick to these smaller FOV eyepieces?

Thanks

 

[John]

2 hours ago, Coolhand1988 said:

....I wonder if the 'old hand' observers still stick to these smaller FOV eyepieces?

 

A lot of them do. I use eyepieces from 40 to 110 degrees AFoV though. Not sure whether I qualify as "old hand" or not ? 🤔

Edited October 7, 2023 by John

[DeanCJ]

2 hours ago, Coolhand1988 said:

 

I wonder if the 'old hand' observers still stick to these smaller FOV eyepieces?

Thanks

 

I have read many posts over the last few years, especially on SGL regarding orthoscopic eyepieces. These eyepieces have a small fov and limited eye relief but seem to provide, from what I have read, a very clear, pure, and sharp view. 
I must admit, I really am tempted to buy one or two just to try them out. 
There must be a market for this type of eyepiece as FLO have a selection for sale in the ‘made in Japan’ section, and they seem to command a good used price. 
As well as my collection of SLV’s I also have the older Vixen LV’s in 4,5,6, and 7mm focal lengths. All of these have a 45°fov and if memory serves me a 20mm eye relief, they work well in my f7 refractor and f10 sct. I bought these used quite a few years ago, and the prices today are somewhat higher.
I forgot to mention that I also wear glasses but I remove them when I am observing, which can be amusing, or annoying for my wife, especially when I can’t see to find them, or when I have managed to sit on them.

 

[Coolhand1988]

56 minutes ago, John said:

 Not sure whether I qualify as "old hand" or not ? 🤔

Lol, going by your very long refractor profile pic, I thought you was.

9 minutes ago, DeanCJ said:

I forgot to mention that I also wear glasses but I remove them when I am observing, which can be amusing, or annoying for my wife, especially when I can’t see to find them, or when I have managed to sit on them.

I was debating about wearing glasses or not when observing. 

I was quoted about wearing glasses straps/cords around my neck when observing without them. Knowing me, I would forget they were there and start looking for them 😄

As I no longer have any of my old eyepieces, I will be starting from scratch and it would make sense to use EPs with long eye reliefs. 

However, Im still tempted by one of the TV Ethos EPs. 

Thanks

[Zermelo]

7 hours ago, DeanCJ said:

I must admit, I really am tempted to buy one or two just to try them out

If you want to try one, you could consider the 10mm BCO.

It performs very well for its price, and the eye relief isn't too bad (not good enough for glasses though).

[Ricochet]

13 hours ago, Coolhand1988 said:

I like the adjustable eyecups, unsure if that is a unique design for these eyepieces?

 

The "look" of them is a Vixen deisgn, and the NLV Plossl range have something very similar. Other eyepieces with twist up eyecups are the BST Starguiders, Pentax XWs, UWANs/Old Nirvanas, Old Meade 5000 SWA/ES Maxvision and probably more that I've forgotten. Televue Delos/Delite have adjustable eyecups via outer barrel sections that slide up and down and are secured at the desired height with a lock ring. 

[Coolhand1988]

5 hours ago, Zermelo said:

If you want to try one, you could consider the 10mm BCO.

It performs very well for its price, and the eye relief isn't too bad (not good enough for glasses though).

Interesting review by J.Huntley on these eyepieces. Good budget as well. 

2 hours ago, Ricochet said:

The "look" of them is a Vixen deisgn, and the NLV Plossl range have something very similar. Other eyepieces with twist up eyecups are the BST Starguiders, Pentax XWs, UWANs/Old Nirvanas, Old Meade 5000 SWA/ES Maxvision and probably more that I've forgotten. Televue Delos/Delite have adjustable eyecups via outer barrel sections that slide up and down and are secured at the desired height with a lock ring. 

Thanks for that information.

I was unsure what other eyepieces have the twist up eyecups.

[Second Time Around]

Vixen NPLs have twist up eyecups.  However, they're either up or down.  If you want an intermediate position all you need to do is add an elastic band or hairgrip at the desired position.

[Coolhand1988]

6 hours ago, Second Time Around said:

Vixen NPLs have twist up eyecups.  However, they're either up or down.  If you want an intermediate position all you need to do is add an elastic band or hairgrip at the desired position.

Thanks, I have just looked at these. The EPs have good customer reviews and their prices are amazingly low.

However the eye relief, has one of the lowest I have seen yet under 15mm FL. The 4mm only has 2.3mm ER.

So far, the Baader Morpheus and the Stellalyra EPs are in the medium end range for my budget and glasses friendly.

Also a quality Barlow or tele-extender, if I decide not to get the lower FL eyepieces, as the former should increase the eye relief for EPs.

Thanks

 

 

 

[JOC]

This another thread in what is a popular subject on SGL.  I am a spectacle wearer I have a respectably strong prescription and a touch of prism in my lenses.  There is an awful lot of mathematical stuff written about what people should and shouldn't be able to see through EP wise both from the perspective of wearing your specs at the EP if you need to wear them normally, not wearing specs at the EP if you normally need to wear them and even similar conversations from people that don't normally wear glasses yet still struggle to see through some EP's.   Eye relief def. plays a part, but at the end of the day everyone is different and what works for one person may for any number of reasons not work for another.  I am def. neither a regular telescope user nor any form of expert in the matter, but I have a mixed box of EP's including some good branded ones and would like to offer up my common sense based observations on the basis of my own experience.

1.  The only EP I've ever completely failed with is a 10 or 11mm Televue Plossl which had eye relief of about 7-8mm I bought that second hand and resold it at no loss.  On that basis maybe things with longer eye relief are easier to use overall whether you wear specs or not and I think from what I read that seems true.

2.  Just because an EP works for someone it might not work for you.  Try buying EP's second hand, try them and resell what doesn't work for you.  Once they have reached second-hand price they seem to change hands at around that mark ad infinitum within a reasonable time period.  You can read threads like this all day, but even if you buy something that someone recommends it might not work.

3.  Don't assume that because you have to wear specs day to day, that you need to wear them at the telescope - I often remove mine and just adjust for focus with the telescope.  FWIW I also find that if I am snorkelling I don't need my specs on to see enough with - looking through the water makes a huge difference.  There are def. some things that you might find you can take specs off for.  A bit like removing them to thread a needle.  Some prescriptions are designed for short and some for long distances, not to mention varifocals - it therefore stands to reason, that not all specs might lend themselves to use at the EP - try taking them off and see how you get on.  

4.  I personally find I get on best with the 'hover above the EP' approach - I am no big fan of the rubber EP guards and mostly fold them down whether I have my specs on or not.   I guess if you are a DSO nut then perhaps the light exclusion from the eye cups is useful, but I am not that dedicated.  FWIW a couple of cheap bar stools one set higher and one set low is a useful investment to sit on and helps you stay still when 'hovering'.  Another advantage to hovering is you are almost automatically compensating for a  little bit of the focus esp. if you don't have your specs on.  However, just because it works for me it might not work for you.  Get a couple of second-hand EP's and get out there.  If they work for you in some way hang onto them - if they don't sell them on and have another bash.