home made Naglers for small refractor

[janoskiss (Steve H)]

Old or unwanted binos are a good source of eyepieces for small refractors that have 25mm (0.97") diameter focusers.

I have an old 60mm f/11.7 refractor which came with 9mm Kellner, 6mm Huygen and 4mm orthoscopic EPs, when I bought it 2nd hand. The 9mm is a good little EP but the 6 & 4 mm are near useless.

I've taken the EPs out of binoculars I no longer need and used 5 min epoxy to glue the bino EPs onto the metal bodies of the telescope EPs (after unscrewing the lens assembly). Here is the result:

http://members.optusnet.com.au/~janosk/misc/diy-eps.jpg

The EP on the left is an original Kellner. The EP in the middle is from the free Andrews 10x32 binos that Lee insists on giving away with every Dob purchase. This EP has an AFOV equalling that of my 30mm GS Superview! Focal length is somewhere between 12 & 15mm. The EP on the right is from an old pair of 7x50 binos that I've been using for star hopping till I got my fab new AOE 7x50s. FL is between 20 & 25mm, AFOV bit greater than a Ploessl.

Ready for some Dob piggyback wide field observing:

http://members.optusnet.com.au/~jano...diy-nagler.jpg

[ving (David)]

field tested yet? what are they like?
I have an old piar of binos I could use, I might try it... does it only work on 1" EPs?

[janoskiss (Steve H)]

They perform really well on clouds, David! Not much else to look at down here.

[ballaratdragons (Ken)]

Steve, try and focus on something about 2k or more away if that is possible from your location. A very distant hill, tower, anything.

How crisp is focus at that distance?

[janoskiss (Steve H)]

The smaller of the bino EPs (the Andrews one) I've used before on Jupiter and it looked good. It was on a wobbly mount, but looked nice and sharp nearly to the edge. I wouldn't expect too much from the bigger EP with nil coating, but it works OK terrestrial targets; seems sharp enough.

[ballaratdragons (Ken)]

Do you realise how many Knockies and EP's are going to be pulled apart now?

It's all your fault Steve!!!

But definately worth a try. Sometimes Cash Converters have half-decent knockies sort of cheap.

[dhumpie]

Maybe you can be the next Paul Rini and sell used wide field and super wide fields for cheap

Darren

[johnno]

Hi All,
You can also use binocular eyepieces in 1"/1/4 focusers by buying some 32mm light weight aluminium tubing,you will have to turn down the outside of the tube a little as it's a little too big as it comes.
Simply cut the tube to length,Araldite the eyepiece in the top,and you have a very cheap eyepiece.
I bought a pair of tasco 7x35 binoculars off ebay,which had an 82 deg fov,
ie, 620 feet at 1000 yards =620/52.5 = 11.8 deg x 7x mag= 82 deg fov.
the focal length of most binocular eyepieces varies from about 18mm to about 22m.
They eyepiece is certainly no Nagler,but is good on m42 for eg,and other wide views.
The other half of the binocular becomes a 7x35 82 deg finderscope.
Regards.John

[Sausageman (Mike Boggan)]

What a great idea!
Now I can fix the little Tasco up, I have a pair of Hanimex 10x50's with coated optics that should do the job nicely.
Janno, you have made my day..good on yer mate.

Mike

[johnno]

Hi All,
Mike,
I would keep the 10x50s for astronomy,they are a good size.
The problem with using the eyepieces from those, is they are usually not wide angle eyepieces.
Most 10x50s have a fov about 5-6 deg,which means at best the eyepieces are 50,60 deg types,not really wide angle.
Your best bet for wide angle is the 7x35,or some of the 8x40s,I have a pair of pentax 8x40s which have a 9.5 deg fov,this means the eyepieces are approx 8x9.5 = 76 deg.(I wont be pulling these apart though)
so as I said IF you want wide angle, keep an eye out for 7x35-8x40s.
Regards.John