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Main
Date: 03 Dec 2006 14:33:36
From: Steve & Lizzie
Subject: Eyepiece construction
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Can anyone help?
After struggling for some time to collimate my newt - I believe I've finally
cracked it!
In the interest of maximising performance I decided that my grubby eyepieces
need a wipe - when I did this there still seemed to be evidence of dirt
inside so I split my 10mm - mistake! Two lenses and a spacer popped out and
now I don't know how they go back!
I've tried a few different ways - each time trying to focus an the roof of
the house opposite mine. Each time I can focus the middle of the image but
the outside is slightly out - if I focus the outside the middle goes
slightly.
Please can someone suggest the correct way for the lenses to go?
Many thanks
Steve
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Date: 03 Dec 2006 08:34:28
From: Curtis Croulet
Subject: Re: Eyepiece construction
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I had a Celestron (Vixen) ortho fall apart. There are three spacers and a
multi-element field lens. It's the spacers that have me (pardon the
expression) baffled.
--
Curtis Croulet
Temecula, California
33°27'59"N, 117°05'53"W
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Date: 03 Dec 2006 09:09:18
From: Shawn
Subject: Re: Eyepiece construction
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Steve & Lizzie wrote:
> Can anyone help?
>
> After struggling for some time to collimate my newt - I believe I've finally
> cracked it!
>
> In the interest of maximising performance I decided that my grubby eyepieces
> need a wipe - when I did this there still seemed to be evidence of dirt
> inside so I split my 10mm - mistake! Two lenses and a spacer popped out and
> now I don't know how they go back!
>
> I've tried a few different ways - each time trying to focus an the roof of
> the house opposite mine. Each time I can focus the middle of the image but
> the outside is slightly out - if I focus the outside the middle goes
> slightly.
>
> Please can someone suggest the correct way for the lenses to go?
>
Try this sight:
http://www.hypermaths.org/quadibloc/science/opt04.htm
Shawn
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Date: 03 Dec 2006 09:46:56
From: William Hamblen
Subject: Re: Eyepiece construction
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On 2006-12-03, Steve & Lizzie <steveandlizzie@blueyonder.co.uk > wrote:
> In the interest of maximising performance I decided that my grubby eyepieces
> need a wipe - when I did this there still seemed to be evidence of dirt
> inside so I split my 10mm - mistake! Two lenses and a spacer popped out and
> now I don't know how they go back!
>
> I've tried a few different ways - each time trying to focus an the roof of
> the house opposite mine. Each time I can focus the middle of the image but
> the outside is slightly out - if I focus the outside the middle goes
> slightly.
The spacer should go between the lenses. There are only eight
different ways two lenses can go together. The spacer can go in
two ways. Sixteen combinations altogether. You might find the
right combination before you do them all.
Bud
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Date: 03 Dec 2006 07:44:28
From: RMOLLISE
Subject: Re: Eyepiece construction
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Hi:
What you're probably seeing is just coma. It was there before you
unwisely took your eyepiece apart.
As far as "where/how" the elements go, what is the eyepiece's design?
(Plossl, Kellner, etc.).
At any rate, let this be a lesson: The Only Enemy of Good Enough is
More Better. It's OK to clean the eye lens of an eyepiece when it is
dirty, but taking your nice ocular apart to chase after that last speck
of dust? Uh-uh...nosir buddy. And don't go cleaning your telescpe
mirrors, either. ;-)
Peace,
Rod Mollise
Author of:
Choosing and Using a Schmidt Cassegrain Telescope
and
The Urban Astronomer's Guide
<http://skywatch.brainiac.com/astroland >
Steve & Lizzie wrote:
> Can anyone help?
>
> After struggling for some time to collimate my newt - I believe I've finally
> cracked it!
>
> In the interest of maximising performance I decided that my grubby eyepieces
> need a wipe - when I did this there still seemed to be evidence of dirt
> inside so I split my 10mm - mistake! Two lenses and a spacer popped out and
> now I don't know how they go back!
>
> I've tried a few different ways - each time trying to focus an the roof of
> the house opposite mine. Each time I can focus the middle of the image but
> the outside is slightly out - if I focus the outside the middle goes
> slightly.
>
> Please can someone suggest the correct way for the lenses to go?
>
> Many thanks
>
> Steve
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Date: 03 Dec 2006 20:58:15
From: Steve & Lizzie
Subject: Re: Eyepiece construction
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Sorry - should have said, this is a 10mm eyepiece. It came with my
Skywatcher 130P and says Super 10mm on the barrel.
Many thanks for the replies so far - I wont be so quick to rush in next
time!
Thanks
Steve
"Steve & Lizzie" <steveandlizzie@blueyonder.co.uk > wrote in message
news:4fBch.47240$qd7.5855@fe1.news.blueyonder.co.uk...
> Can anyone help?
>
> After struggling for some time to collimate my newt - I believe I've
finally
> cracked it!
>
> In the interest of maximising performance I decided that my grubby
eyepieces
> need a wipe - when I did this there still seemed to be evidence of dirt
> inside so I split my 10mm - mistake! Two lenses and a spacer popped out
and
> now I don't know how they go back!
>
> I've tried a few different ways - each time trying to focus an the roof of
> the house opposite mine. Each time I can focus the middle of the image but
> the outside is slightly out - if I focus the outside the middle goes
> slightly.
>
> Please can someone suggest the correct way for the lenses to go?
>
> Many thanks
>
> Steve
>
>
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Date: 03 Dec 2006 22:21:59
From: gobbletwo
Subject: Re: Eyepiece construction
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Steve & Lizzie wrote:
> Sorry - should have said, this is a 10mm eyepiece. It came with my
> Skywatcher 130P and says Super 10mm on the barrel.
>
> Many thanks for the replies so far - I wont be so quick to rush in next
<snipped >
I see you folks are in the UK. Skywatcher scopes are not sold in the US,
under that name.. ;-) Brady Johnson, in Canada, is a Skywatcher dealer
(a very good one,too) and should be helpful. Google kw-telescopes and go
from there. Good luck.
jon
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Date: 03 Dec 2006 19:17:10
From: Sam Wormley
Subject: Re: Eyepiece construction
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Steve & Lizzie wrote:
> Can anyone help?
>
> After struggling for some time to collimate my newt - I believe I've finally
> cracked it!
>
> In the interest of maximising performance I decided that my grubby eyepieces
> need a wipe - when I did this there still seemed to be evidence of dirt
> inside so I split my 10mm - mistake! Two lenses and a spacer popped out and
> now I don't know how they go back!
>
> I've tried a few different ways - each time trying to focus an the roof of
> the house opposite mine. Each time I can focus the middle of the image but
> the outside is slightly out - if I focus the outside the middle goes
> slightly.
>
> Please can someone suggest the correct way for the lenses to go?
>
> Many thanks
>
> Steve
>
>
Tell us the eyepiece brand, model, type in addition to the focal length,
so we have something to go on.
-Sam
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Date: 04 Dec 2006 03:23:23
From: Sam Wormley
Subject: Re: Eyepiece construction
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Sam Wormley wrote:
> Steve & Lizzie wrote:
>> Can anyone help?
>>
>> After struggling for some time to collimate my newt - I believe I've
>> finally
>> cracked it!
>>
>> In the interest of maximising performance I decided that my grubby
>> eyepieces
>> need a wipe - when I did this there still seemed to be evidence of dirt
>> inside so I split my 10mm - mistake! Two lenses and a spacer popped
>> out and
>> now I don't know how they go back!
>>
>> I've tried a few different ways - each time trying to focus an the
>> roof of
>> the house opposite mine. Each time I can focus the middle of the image
>> but
>> the outside is slightly out - if I focus the outside the middle goes
>> slightly.
>>
>> Please can someone suggest the correct way for the lenses to go?
>>
>> Many thanks
>>
>> Steve
>>
>>
>
> Tell us the eyepiece brand, model, type in addition to the focal length,
> so we have something to go on.
>
> -Sam
>
>
From: http://homepage.ntlworld.com/robin.scagell/reviews/Explorer%20130M%20EQ2.html
The eyepieces supplied are 25 mm and 10 mm, labeled simply as
'Super Wide Angle Long Eye Relief'. The barrels are plastic and
they feel very lightweight compared with, say, the Plössls supplied
with Meade telescopes. They are actually *modified Kellner eyepieces*
which do give a wide apparent field of view and have good eye
relief. Only an increased amount of false colour from about half
way out from the field centre shows that they are not Plössls, but
they are quite adequate for general viewing, particularly at the
centre of the field of view. The Barlow, however, leaves something
to be desired as it introduces noticeable amounts of false colour.
Even so, the results are not terrible so it is an achromatic
Barlow, and I could see the Airy disc using it with the 10 mm
eyepiece. I did get better results when using other eyepieces, so
it would be a good idea to purchase a new eyepiece at some stage to
get the best out of the instrument. I was able to use a Celestron
7.5 mm eyepiece with 2x Celestron Barlow, giving a good image of
the Double Double, with both pairs of stars well separated. Any
higher powers should not show any more detail because at this
magnification you are simply magnifying the Airy disc even more.
The eyepieces did take standard filters, and I was able to view the
Veil Nebula using a Meade OIII filter under average conditions.
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Date: 04 Dec 2006 03:40:32
From: Sam Wormley
Subject: Re: Eyepiece construction
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Sam Wormley wrote:
> Sam Wormley wrote:
> From:
> http://homepage.ntlworld.com/robin.scagell/reviews/Explorer%20130M%20EQ2.html
>
>
> The eyepieces supplied are 25 mm and 10 mm, labeled simply as
> 'Super Wide Angle Long Eye Relief'. The barrels are plastic and
> they feel very lightweight compared with, say, the Plössls supplied
> with Meade telescopes. They are actually *modified Kellner eyepieces*
> which do give a wide apparent field of view and have good eye
> relief. Only an increased amount of false colour from about half
> way out from the field centre shows that they are not Plössls, but
> they are quite adequate for general viewing, particularly at the
> centre of the field of view. The Barlow, however, leaves something
> to be desired as it introduces noticeable amounts of false colour.
> Even so, the results are not terrible so it is an achromatic
> Barlow, and I could see the Airy disc using it with the 10 mm
> eyepiece. I did get better results when using other eyepieces, so
> it would be a good idea to purchase a new eyepiece at some stage to
> get the best out of the instrument. I was able to use a Celestron
> 7.5 mm eyepiece with 2x Celestron Barlow, giving a good image of
> the Double Double, with both pairs of stars well separated. Any
> higher powers should not show any more detail because at this
> magnification you are simply magnifying the Airy disc even more.
> The eyepieces did take standard filters, and I was able to view the
> Veil Nebula using a Meade OIII filter under average conditions.
>
Edmund's RKE (modified Kellner) eyepieces might provide some
guidance with the cemented pair closest to the eye.
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2075&search=1
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