Eye Relief

[Yendor]

So where and how do I begin to understand what I will need to buy as far as making good viewing possible. I wear specs for short sight, and I'm Astigmatic. Are these things made in a variety of sizes, and if so how do I choose the correct one. Do they attach to the eyepieces that come with a scope, or are they part of a replacement item I might need to buy.

[g0ibi]

Good question, I am the same as you (optically!) I shall be following any constructive answers you get closely. I tend to roll back the eye cups on most of my EP's the same as I did on my bino's during 20 years of birdwatching, works for me!

[John]

Eyepieces have a characteristic called eye relief - the distance that your eye needs to be from the top lens of the eyepiece to take in the full field of view. Some eyepiece designs have longer eye relief and, without any specific knowledge of your needs, it sounds to me that these long eye relief designs might be for you. You may find this article by Al Nagler (hte founder of Tele Vue) of interest:

Tele Vue Optics: Determining When To Use Eyeglasses

Tele Vue manufacture a special device called the Dioptrx which claims to be an astigmatism correcting lens.

[Yendor]

Thanks for the link....... Not sure I understand what its telling me? I know, I really am a duffer!! So I think perhaps the question I posted isnt going to have an easy answer. I really do have a steep learning curve dont I? I must try and study the information about the eyepeices that come with my scope when I get it, try and learn about them.

I never realised the rubber cups on binoculars could be turned down. Well I never :-) I feel a double helping of embarrassment coming on.

[John]

What would help would be some input from someone who is in a similar situation to yourself and has been through the learning curve already

The eyepieces that come with the scope (which scope by the way ?) will at least allow you to experiment. They will be rather basic but there are many options available, in due course, for improving on them

[Yendor]

I haven't fully made my mind up with regard to scope choice? I think perhaps I need to see and use them first. It'll be either a Skywatcher 200p or a Skywatcher Mak 127, both very different

Ive read so much stuff about Eye relief and while I think I can grasp the basics, I think maybe I need to go and tallk to someone in the business of selling the eyepieces. Excellent idea, hopefully someone with the a similar eye condition may be able to have input. Thanks

Eye Relief And Eyecup Design Technical Guide Article by Eagle Optics

I found the above link. Moderator please delete if it infringes any forrum rules.

[CAB]

Hi I have the same eyesight as you and use glasses for observing. The eypieces I have all have good eye relief for glasses wearers. My Williams 4mm UWAN has a twist up and down eye cup so it can be ajusted for glasses and non glasses wear.

I know it all sounds confusing but basically when wearing glasses it puts extra distance between your eyeball and the lens of the eyepiece. Eyepieces with better eye relief mean that you can have your eyeball further away from the lens and still see the full field of view the eyepiece can give. This does not mean you cannot look through other eyepieces with glasses on you just need to move your head around slightly to see the sides of the view. Once you decide on your scope it will be easier to find some suitable eyepieces for you. I have some at all budget levels that are fine for glasses use.

[Bukko]

Hi, guys,

I wonder if this will help.

I am also short sighted with astigmatism and here is my last pescription, left eye for comparison..

Sph: -6.5, Cyl: 2.00, Axis 172

I have several eyepieces and can get by with most of them. The bigger the focal length of the EP, the easier they seem to be, as generally, the eye relief is bigger.

I favour a good 10mm eyepiece and use a Barlow to get the magnification, rather than using a 5mm with the (generally)smaller eye relief.

However, I can also manage without the glasses; I just need to adjust the focus and I can get a pretty sharp view without them.

Gordon.