2" 36mm Eyepiece

  2" has a 70 deg. FOV and 20mm's eye relief.

 Compact in size and only 9 oz.

No "Blacking out" or "Pin Cushioning" 

  2" is $229 (Ob236mm) Brass add $70

35mm Pan vs. Siebert Observatory 36mm. Both are sharp to the edge in fast scopes but the OB wins on pin cushioning and it also has eye relief that people with eye glasses will appreciate. >>>>>>>>>>>>>>>>

All Observatory. eyepieces are under 9 oz.

Were did the Observatory Series eyepieces come from. Click here

Large optics reduce apparent vignetting.

Click on picture to enlarge. Here is the eyepiece comparisons page. 

Observatory eyepieces are known for their excellent edge correction. The 34mm and 36mm are sharp to the edge at f5 and very good at f4.5 without a Paracorr.

2" 34mm Eyepiece  

2" has a 70 deg. fov and 20mm's eye relief.

 Compact in size and only 9 oz.

No "Blacking out" or "Pin Cushioning" 

    2" is $229 (Ob234mm)Brass add $70

All Observatory. eyepieces are under 9 oz.

Large optics reduce apparent vignetting.

Click on picture to enlarge. Here is the eyepiece comparisons page.

Observatory eyepieces are known for their excellent edge correction. The 34mm and 36mm are sharp to the edge at f5 and very good at f4.5 without a Paracorr.

 Observatory Elite

This line has many professional and  amateur applications

Click on pictures below.

 2.7" and 3" 65/70mm

 4"  65/70/80/90/100/120mm

FOV 2,7" 65/60deg

FOV 3"    70/65deg

FOV 4"    70/70/65/60/55/50deg

2.7" 65-70mm $799 Brass add $299  3.1lb.

3" 60-70mm $999  Brass add $399  3.5lb.

4" 60-120mm  $1199  ( Brass add $499  4.3lb.

 All T-6 and Delrin construction

Fully Anodized black.  

No "Pin Cushioning" 

 Has removable camera provision for both 1.25" and 2" adapters >>>>>>

Doubles as top end cap.

Bottom Delrin cover.

Info and prices on 2.7" and 3" eyepieces above.

Observatory Elite 80mm 4 inch eyepieces are 6 element.

The first prototype 80mm 4" eyepiece made in this series was sent to the Mount Wilson observatory for use in their 60" Cas

Feed back with the 80mm eyepiece when used with the 60" was completely positive.  

Were did the Observatory Series eyepieces come from. Click here

 This eyepieces come with top and bottom Delrin dust caps. The top dust cap has a  2" and 1.25" stepdown built in to it for eyepiece projection photography to be done on it. This makes it easy to attach your camera to the eyepiece with little or no additional hardware.

------------------------------------------------------------------------------------

  4 " Eyepieces

Here Above compared to a 40mm Pentax XL.

And below shows the mounted on camera adaptor

4 " Eyepieces

----------------------------------------------------------------------------------------

  2.7 and 3" Eyepieces These eyepieces are great for your long F.L. backyard Observatory scopes. The eyepieces below will give you twice the amount of sky possible for your largest field stop

12" - 16" Cassegrain scopes

5" and larger long F.L. refractors.

EX: 6" f15 refractor F.L. 2268mm 1.15deg True FOV. with a 46mm Field stop (41mm Panoptic) Now with the Elite 65mm and it's 65mm FS. now has a 1.63deg True FOV. Now that sounds like only about 40% gain in true FOV but the amount of sky you are now covering is twice the amount sky area. This will hold true for any scope you use. More facts below.

Exit Pupil with 65mm and 70mm at F15 is      = 4.3mm  and 4.6mm

Exit Pupil with 65mm and 70mm at F12.5 is   = 5.2mm  and 5.6mm

Exit Pupil with 65mm and 70mm at F10 is      = 6.5mm  and 7.0mm

Click on eyepiece pictures below to enlarge.

What scopes can use the 60mm-120mm?  Well for taking pictures they can be used with any  F-ratio scope since any large CCD chip will benefit from the 40mm-50mm eye lens and huge optics. In fact it may be the lowest possible power photo you could take through your scope is with projection imaging. 

Almost anyone's Exit Pupil can use an 80mm eyepiece at over (f-13)

 2.7" 3" Diagonals

Level 1

2.7" Diagonals   

3" Diagonals 

2.7" inlet to 3" outlet  

3" inlet to 2.7" outlet  

Black Anodized. $1249

++++++++++++++

Level 2a

2.7" Diagonals L2  

3" Diagonals L 2 

2.7" inlet to 3" outlet  L 2

3" inlet to 2.7" outlet  L 2 

Black Anodized. $1799

  T-6 and Black Delrin construction.

++++++++++++++

Level 2b

2.7" Diagonals   

3" Diagonals  

2.7" inlet to 3" outlet  

3" inlet to 2.7" outlet  

Black Anodized. $1799

 T-6 and Black Delrin construction.

L1:  Diagonal are 10th ~ and  99% reflective. Precision Annealed Pyrex.

L2a:  Diagonal are 20th ~ and  99% reflective.  Fused Silica for Enhanced Thermal Stability and Scratch Resistants. Black Anodized.

L2b:  Diagonal are 20th ~ and  99% reflective.  Zerodur-"Ceramic" for Unmatched Thermal Stability. Black Anodized.

All diagonals are fully and easily  collimatable. 

 All T- 6 and Black Delrin construction, Fully baffled.

60 day return policy. "No restock fees"

Pictures soon to come.

One such project to build an eyepiece for an historic Observatory is describes here below.

In this case I was asked to build the following:

It was thought that the ideal deep sky eyepiece for the Lick Observatory
 36" f19 refractor would be as follows:
>
 116mm focal length (would yield a 6mm exit pupil)
 134mm (5.27") diameter field stop
>
 The above is based on a 60 degree apparent field.  If  the FOV was to be narrower then the 116mm focal length should be
 longer. This eyepieces is to have 20mm ER so it could be used with or without eyeglasses.

The reason such an eyepiece might be needed described below.
>
 The Lick refractor is steeped in history and is the largest
 refractor in daily use today.  Currently they observe with a
 55mm Plossl, which provides only 0.15 degree field.


 This information was based on my conversation. with Alan Adler from the Lick Observatory in Diablo Range east of San Jose, California,

An eyepiece would be needed that would give a .25 deg instead of the .15 deg he was getting with their present eyepiece.

Click to the Lick  website  http://mthamilton.ucolick.org/ 

Much time and expense was put into the Observatory eyepiece project to help these type of large observatories.      These costs can never be recouped from selling single eyepieces for these specific scopes. Put into other words: You can't make a living on this type of work but here is the good news. 

The time an research that went into the project to create those eyepieces can  be brought into the world of amateur astronomy and applied to the relatively modest scope that are commonly available.

The 2" 34mm, 36mm and 40mm Observatory Series are the byproducts of this research. These have been scaled down from the original's but this makes them no less significant.

So there's nothing mystical about the name of these eyepieces. In fact the name that has been chosen for this series could not be any more descriptive of their origin. 

Harry Siebert / Siebert Optics.