Yes Tony it's a lot of money for a little extra performance in the nagler 31 and the ES 30 at the current price is a winner but I was surprised to see as I went through archived posts that the ES 30 has never come up for sale ever on iis,it has been in the wanted list but not for sale,someone might prove me wrong but when I went through the archives last night didn't see one ,to me that speaks volumes
...when I went through the archives last night didn't see one ,to me that speaks volumes
There are a lot fewer ES 30mm out there than T5 31mm, that's all. Considering how many T5 31mm are out there (rare to go to a star party and not see one) there aren't many of those sold second hand either.
I like my ES 30 82 a lot. Pinpoint stars to the edge in my 6"f12 frac and 10" f4.8 Newt with coma corrector. Mostly I use it in my 4" f5 Achro where a small bit of FC (from the objective) shows in the outer 20%...a tiny turn of the focuser fixes that...very happy.
I bought 30 82 used on IIS about two years ago. There was one for sale last year, but the ES sale price is good. I'll be buying the ES 24 82 soon.
I think that there must be a few 30's out there as explore scientific has completely sold out but they can be back ordered,my eyes must be failing me I didn't see those 2 ,it's seems like it is a rare type on the used market
I've looked through the ES82 30mm a couple of times in other people's scopes. I wasn't doing any kind of critical evaluation but it is certainly a stunning eyepiece.
My ES 30 82 landed today and in not perfect conditions gave it first light ,scope used SV80ED on a Vixen porta ii mount,no weight issues thank goodness ,the views were nothing short of awesome,pinpoint stars across the FOV and did what i really wanted to be able to do view huge sections of the night sky but the biggest surprise for me was the contrast ,very similar to my XW's and is a definite keeper .would like to thank those that suggested this eyepiece to me as it is TBH more than i expected and can't wait to get out and view through it again
I've owned both the 30mm ES 82 and I now own my second 34mm ES 68. Sold my first 34mm ES 68 to get the 30mm ES 82....I like the 34mm ES 68 more because of:
1. Longer eye relief
2. Sharper stars with less flaring on axis
3. Less weight
The scope I tried my 30 82 in is f7 and had none of those problems the stars were very sharp across the whole fov,I noticed your scope is f4.7 which would test most eyepieces,have a wo zs66sd f5.9 ,will try it in that scope to see if it performs the same
It is a big eyepiece but the 24mm er is plenty for me
The scope I tried my 30 82 in is f7 and had none of those problems the stars were very sharp across the whole fov,I noticed your scope is f4.7 which would test most eyepieces,have a wo zs66sd f5.9 ,will try it in that scope to see if it performs the same
It is a big eyepiece but the 24mm er is plenty for me
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,484
exit pupil considerations
The points made about apparent fields of view and astigmatism are relevant.
When selecting eyepieces, exit pupil is another consideration. While a healthy young persons eyes may dilate to 7mm, older observers may be limited to 5-6mm. If the scope exit pupil exceeds your pupil dilation you are not utilizing the full aperture, light from the outer part does not enter your pupil reducing the effective diameter of the scope.
EXIT PUPIL(mm) = EYEPIECE FL(mm) χ telescope ratio
another way to look at it is for a 7mm exit pupil :
Longest useable eyepiece focal length = ratio x 7
So for an f4.7 scope, 33-34mm is the about the longest eyepiece you should purchase. If you want wider fields, the 30mm or 31mm x 82 deg eyepieces are a better way than going to longer focal lengths.
Some people go longer just because they want the low power and accept the loss of light. Just also be aware that the central obstruction from the secondary starts to become visible as a dark central patch at large exit pupils. This can be quite annoying.
i am looking for advice on a low power,widefield eyepiece,i only want to buy one so it's critical i buy right first time,my scopes are WO66SD,SV80HD and a SW100HD if i could get some clarity on the eyepiece to suit the scopes i have it would be most appreciated.
I hear this all the time from people: "I only want to buy one, forever, so tell me what I should buy."
The truth is, until you have a lot of experience with eyepieces and observing, you simply won't know what will work perfectly for you.
It's unrealistic to expect to buy an eyepiece, any eyepiece, that will suit you forever as your tastes and needs change.
There are a lot of good eyepieces, and it might be better to ask about specific ones.
You can download my 2016 Buyer's Guide to Eyepieces to get an idea of what is available and then go from there: http://www.cloudynights.com/topic/53...-buyers-guide/
If you are under 40, look for an eyepiece that yields a 6-7mm exit pupil (Eyepiece Focal length / Telescope f/ratio). If you're 40-60, try a maximum of 5-6mm, and if 60+, try for a maximum exit pupil of 5mm.
I ended up buying a ES 30 82 after advice given on this post and can honestly say it has lived up to more than my expectations and couldn't ever see me selling it,i have bought an sold many eyepieces but have found that this eyepiece along with a pentax xf and xw's i have do the job for me but do take on board your advice through the experience you have
