Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

Explore Scientific eyepieces - get them while you can in the UK

simonfletcher7

By simonfletcher7
in Discussions - Eyepieces

Recommended Posts

  • Replies 521
  • Created
  • Last Reply
Naemeth

Naemeth

Posted
Posted

LOL I'm travelling light, carry-on bag only :eek:

Hence the challenge...I've got less than 24 hours to place an order to get it delivered by the time I'm there... what not to buy??? :evil:

Dunkster, I have most helpfully changed your post for you :lol:.

Perhaps get some of the 100 degree ES EPs :)

Link to comment
Share on other sites
Dellis

Dellis

Posted
Posted

Yes, I agree. For £200 this is an excellent hyper-wide eyepiece :smiley:

I bought an eyepiece from Algady, he's a really nice guy. The 8.8/82 I bought off him was like new and when I started to correspond with him over the e.p. I realised we'd met at The Peak Star Party and I'd already looked through the e.p. I was buying, small world.

Dave

Link to comment
Share on other sites
Doug

Doug

Posted
Posted

Could one of you lucky guys measure the size of the box please? I've been asked to drop in to our US office next week and wonder if it would fit in carry-on ... :huh:

Dunkster

If you talking about the 100 fov eyepieces the box is 6.5 x 6.5 x 7.5 the answer is yes I would get them all If I was you :evil:

Link to comment
Share on other sites
John

John

Posted
Posted

Finally arrived, all I need now is a clear sky....it's big! Total cost £260 or thereabouts

Nice - I've had mine for a couple of weeks now but only limited time to use it, unfortunately.

I find it's more immersive with the eyecup rolled down.

Link to comment
Share on other sites
OneEyedSam

OneEyedSam

Posted
Posted

In your f5.3 scope how sharp is the image at the edges ? My dob is f5, hoping for great views. Wow that 100 degree field is wide, looking through it just now into the (blurry) garden, you cannot see the edge of the field.

Link to comment
Share on other sites
John

John

Posted
Posted

In your f5.3 scope how sharp is the image at the edges ? My dob is f5, hoping for great views. Wow that 100 degree field is wide, looking through it just now into the (blurry) garden, you cannot see the edge of the field.

It's sharp across about 90% of the field. In the last 10% it's actually starting to show coma (which is scope generated rather than eyepiece generated) more than astigmatism. You might find this eyepiece prompts you to investigate coma correctors for your F/5 scope.

I can just perceive the edge of the FoV with the eye cup rolled down but who wants to see it ? - it's the "endless pool of stars" impression that I'm after with these eyepieces. If I liked looking at field stops I'd get orthos instead !

Link to comment
Share on other sites
John

John

Posted
Posted

I can't see field stops in 82s without moving my head quite a lot. How do you even get close to seeing it all in a 100 degree without moving your head? !

I don't find I need to move my head around with either my Naglers or my Ethos / ES 100's. I'm only seeing the field edge out of the "corner of my eye" so to speak but that suits me fine !

I have to say that 82 degrees looks a little cramped once you have used 100. Sounds crazy but that how it seems to me !

I've no problem with narrower fields of view either though, if the eyepieces do a great job :smiley:

There is just so much choice available these days - something to suit everyone really !

Link to comment
Share on other sites
Stargazer_00

Stargazer_00

Posted
Posted

Yeah there is. I need to avoid looking at 100 degrees for at least a while. When I looked at my first 82 from a 60 I just knew then that I would be happy with nothing less than a set of 82s. Having acheived that all I need now is to get the same inclination again but for 100 degrees!

Link to comment
Share on other sites
Stargazer_00

Stargazer_00

Posted
Posted

I don't find I need to move my head around with either my Naglers or my Ethos / ES 100's. I'm only seeing the field edge out of the "corner of my eye" so to speak but that suits me fine !

I actually just looked through all my eyepieces at lunch and you're right you can see the field stop, just, in the periphial vision. If you look straight into the eyepiece and then move your eye to look for the field stop and not your head then you crop the view significantly, by as much as 30%. If you go looking for the field stop to look at directly you have to move you head but I devised a test. I lined up the eyepiece on a rooftop with only the top edge of the field stop showing a tiny portion of sky, by looking at that part of the field stop. I then looked directly into the eyepiece to see if I could see any sky in the periphiary and I could.

So if you want to look at the field stop then you have to move your head but if you look directly into the eyepiece's centre of FOV your periphial vision will be gathering light from the edges, you just wont be able to see it in focus wihout moving your head to align the field stop in the centre of your eye's vision.

I appreciate you already knew this, just recounting a test I devised and it's results is all.

How does this test work on a 100 degree, can you see the sky in the corner of your vision or just rooftop?

Link to comment
Share on other sites
John

John

Posted
Posted

I've just compared the views with my Nagler 31mm, ES 20mm 100 and Ethos 13mm in my ED 102 F/6.5 refractor. No rooftops on view, just a distant pine tree.

I can see the Nagler 31's field edges quite easily with the eye cup rolled up, when looking at the centre of the field. With the ES 20, I can't see the field edges with the eye cup up without tilting my head. With the eyecup down I can just see the edges of the field in peripheral vision while looking that the field centre. With the 13mm Ethos I can just perceive the field of view edges with the eye cup rolled up - no need to tilt the head.

Now my eyeball might be scanning around during the above, I'd need to film it to see if that is happening and I'm not sure how to do that !.

The above results tally more or less with the eye relief for the 3 eyepieces - 19mm for the Nagler 31, 14.5mm for the ES 20 / 100 and 15mm for the Ethos 13mm. Eye relief should be (I think) the distance the eye needs to be from the top surface of the eye lens at which the full field of view is visible. If the eye lens is recessed a bit then the physical eye relief seems tighter as you have to jam your eye closer to the top of the eyepiece to hit the correct eye distance. The ES 20 / 100's eye lens is recessed a couple of mm further inward than the Ethos, which accounts for why you need to roll the eye cup down on the latter, I reckon.

Field of view is only one aspect of these eyepieces though - their contrast, light throughput, light scatter control and sharpness needs to be, and is, excellent across the whole field of view to make them really useful tools :smiley:

Link to comment
Share on other sites
Doug

Doug

Posted
Posted

Yeah there is. I need to avoid looking at 100 degrees for at least a while. When I looked at my first 82 from a 60 I just knew then that I would be happy with nothing less than a set of 82s. Having acheived that all I need now is to get the same inclination again but for 100 degrees!

It is so easy to get court up in this as i have found out I've just seen on a USA site a Meade 24mm UWA with Meade diagonal 2" for $159.00 what a bargain :evil:

even though I have 100 fov I will still be using my 82 fov they give wonderful views and I still use a Meade 18mm 1.25, I have always enjoyed the view in this eyepiece

Link to comment
Share on other sites
Stargazer_00

Stargazer_00

Posted
Posted

It is so easy to get court up in this as i have found out I've just seen on a USA site a Meade 24mm UWA with Meade diagonal 2" for $159.00 what a bargain :evil:

even though I have 100 fov I will still be using my 82 fov they give wonderful views and I still use a Meade 18mm 1.25, I have always enjoyed the view in this eyepiece

That deal is what got me started with importing in the first place. See the other thread I made on here and you'll even see it in one of my scopes :)

Link to comment
Share on other sites
Doug

Doug

Posted
Posted

Finally arrived, all I need now is a clear sky....it's big! Total cost £260 or thereabouts

Nice one Sam congratulations again here's hoping the weather gets better now we are comming to the end of all the buying :grin: for me in my area I have rain tonight and Snow tomorrow and bad weather up till tuesday Just my luck :sad:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.