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 $199 (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 $199 (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.

2" 40mm 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 $199 (Ob240mm)Brass add $70

The 40mm is Best used at over f6

 Observatory Elite

 2.7" 60/65/70mm 

 3" 60/65/70/90/120mm

 4" 60/65/70/80/90/120mm

FOV 2,7" 72/70/65deg

FOV 3" 72/70/65/65/50deg

FOV 4" 72/70/65/65/50deg

2.7" 60-70mm $799 Brass add $400

3" 60-120mm $1199  Brass add $500

4" 60-120mm  $1349  ( Brass add $650

 All T-6 and Delrin construction and only 4.3lb. Fully Anodized black. 

  Here compared to a 40mm Pentax XL >>>>>>>>>>>>>>>>>>>

No "Pin Cushioning" 

 Has it's own camera provision for both 1.25" and 2" adapters >>>>>>

Doubles as top end cap.

Observatory Elite 90mm 4 inch eyepieces is 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

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 you camera to the eyepieces with little or no additional hardware. Huge optics are in these eyepieces

What scopes can use the 600mm-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. 

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

Many have asked where this series came from and the time has final come to tell the story.

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 eyepiecewould 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.