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Kowa TSN-820 alternative Eyepieces (2 Viewers)

robson_h

Member
Hello,

i adapted an Nikon FEP-30W Eyepiece to an TSN-824 and have some pictures to show. For me the quality of this Eyepiece is unbelievable.

The original Bajonett is srewed to the Eyepiece. The plastic housing is secured with a threw ring. I was able to unscrew this with a slide gauge. I do not own a Nikon EDG Scope. I have bought the Nikon for the Kowa.

Robert
 

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robson_h

Member
more

The picture of the linden leaves is done with a smartphone hold directly to the beam of the eyepiece. The last picture shows my super old lathe i made the adapter with.
The Adapter is attached to the Kowa with three screws to the outer Thread of the Kowa. It is made of strong Aluminium 7075. The white Adapter Ring for the Nikon is made of Plastic and has 2'' diameter.

No need to glue, everything holds.
Focus goes from 6 Meters to infinite.

Robert
 

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jring

Well-known member
Hi,

wow, looks very nice - mechanically and optically too - the EP has nice field flattening ist seems... sharp to the edge.

Joachim
 

mayoayo

Well-known member
Yes looks great..Massive eyepiece! (maybe looks bigger than it is). The picture image looks very good indeed, I am sure visually is an amazing eyepiece...This eyepiece is 30X on the EDG, and although unsure of The FL differences between the EDG and 824 , it is safe t o assume that the EDG has a longer, perhaps considerably longer FL than the 824, so this eyepiece must be closer to 25x than to 30X in your kowa.. What is the inner diameter of the plastic ring? Seems to me that you couldn have turned a smaller threaded ring to attach to the bottom part of the eyepiece and screw in the 824 bayonet inner threads, to save some weight.. Maybe a future project...
 
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robson_h

Member
Hi Mayoayo,

the Nikon FEP-30W is heavy and huge!

https://imaging.nikon.com/lineup/sportoptics/scopes/edg_fep/spec.htm

Without the Nikon Housing it has 376g. The Plastic Ring has 12g and the Aluminium Adapter 41g.

The Diameter of the exit Pupil is close to 2,8mm shown in the picutre. The magnification is calculated like this 82mm/2,8mm = 29,2

It is possible to build an adapter to directly fit the Nikon 42,4mm to the scope. I decided to use 2'' size because this fits to my Newton Teleskope.

Robert
 

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mayoayo

Well-known member
Yes, the exit pupil shows the magnification indeed.. This data means that the EDG has a FL closer to that of the 824 versus the speculation, years ago, that the scope had a long focal length similar to the 525 mm of the Fieldscope 82
 

robson_h

Member
Hello Yves,

the nikon performs realy great. I don't have the 32x and can not compare them.

I spend some more money. Bought a used Nikon DSA-N1 Digiscoping Adpater. The Adapter fits to the Nikon Eyepiece and has a Nikon 1 Bajonett. Bought a used Nikon 1 V3 camera. :king:

Here are some Pictures...
 

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robson_h

Member
Yesterday at Castle Königstein. I was there to see the Eagle Owl.

I have not found the Owl. Maybe it already left the castle. I have found a Kestrel and made this picture. He was far away. I have not tuned the picture in Photoshop. It is what the camera captured. Not cropped.
 

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robson_h

Member
Hello Joachim,

the littlle one in your video is Buddhine. Yesterday we arrived at the castle at 8 a clock. And no owl was there. We had a pizza in Königstein and returned to the castle at 9:30. We walked around the castle. It was dark and no Owl was there. The Webcam is inside the castle and it is closed at night.

Two weeks ago i had more luck and made this picure of Buddhines father.
 

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jring

Well-known member
Hi,

I think it used to be closed all the time due to the owls nesting there... might have re-opened lately though...

Joachim
 

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