DIY eyepieces!

[Chaz2b]

Having seen this guy on YouTube describing and showing how to make cheap, but really good eyepieces from old binoculars, I thought, wow! I have a couple of old binos around, got them for free as they were chucked out!

I followed his instructions, one Bino was not really suited as it’s all plastic with the objectives glued in.

But after constructing two small eyepieces and three objective eyepieces, I was amazed how good they are. 
I didn’t quite enjoy the large eyepieces in my maksutov as it revealed the central mirror, so in my TAL 100rs it wasn’t a problem.

Firstly, the view in the LOEs (large objective eyepiece) had to be viewed with a fair amount, and I mean a fair amount of eye relief, but the view was crisp and had a great depth of field, I compared this with my 2” erfel, the LOE was better in both respects, although it was more comfortable to get up close to the erfel.

The SBE, (small binocular eyepiece) was also very competitive to normal plossls, giving again a good depth of field. 
This is in daytime viewing looking at various distant and close objects.

If you want to try it yourself, don’t forget you will be partly destroying the binos, then follow …maplebridge48 “making an RDP ( reds double plossl ) telescope eyepiece” on YouTube.

have fun,

chaz

I have to add, in one of his videos, he mentions  Televue ethos, I’ll leave you to find out why.🤐

Edited May 17, 2023 by Chaz2b
Added photos

[doublevodka]

More info here on the Facebook group if that helps - A Second Look: Reusing Old Lenses for Astronomy 

 

 

[Chaz2b]

Yep, same guy. Didn’t know the group existed so thanks for the link.

chaz

Edited May 17, 2023 by Chaz2b

[Spile]

Red Henry is a wonderful chap, who posts out free eyepieces across the USA. 

[Chaz2b]

Question, am I binoviewing with one eye!?

Chaz

 

[GrumpiusMaximus]

I'm in the process of acquiring the parts for an eyepiece constructed from two pairs of 10x50 binoculars.  I've only had one pair delivered so far but on a quick dry assembly I cannot believe how simple it is.  It will take me about 10 minutes to assemble the whole thing once I've got all the bits!

If you are thinking of giving this a go, you'll need 50mm internal diameter steel tubing, not the 50.8mm, as a 2" focusser/diagonal is 50.8, so the barrel needs to be undersized.  I've bought some mild steel tube from eBay and it fits perfectly and I'll paint it for corrosion protection and preventing internal reflections.

I also took one of the smaller lenses from the binocular and converted it as it all just fits with a cheap 1.25" barrel from a spare (cheap) eyepiece.  I'll test it properly when I next get my small telescope out but daytime testing has demonstrated that it's not bad.  Not as good as my WO 20mm Swan - but usable in daytime.

I'm surprised to see so few people trying this!  The donor binoculars cost less than 10GBP each (including shipping) and the 50mm tube was around 13GBP for a length that will do ten eyepieces.  Some paint and epoxy (or superglue) and LX tape are fairly nominal costs too, so for around 35GBP I can apparently have a decent 50mm.

Will report back on performance of both the 1.25" eyepiece and 2" eyepiece when fully constructed and tested under a decent sky!

[Louis D]

There's a person over on CN, Martin Pond, that at least used to post quite a bit about his tinkerings with various home brew eyepiece designs made mainly from surplus binocular optics.  There are several more folks tinkering and sharing ideas there as well.  They also mention a Facebook group as well for homemade eyepieces.  Hunt around a bit, you might find some fellow eyepiece builders out there to share ideas with.  It's a subject that indeed comes up rarely on SGL, but a search here might be worthwhile as well.

[GrumpiusMaximus]

I'll have a look.  I'm aware of the Facebook group but haven't been on that site since 2010.  There are various things about.  Might give me an excuse to buy a 3D printer to make housings...

[GrumpiusMaximus]

Made up an eyepiece this afternoon.  It's a bit crude but I've just been giving it a go through my 70ED.  It's ridiculously oversized and the exit pupil at 8.3mm is bigger than I can take full advantage of but first impressions are good.  I've made an eyecup out of some thin foam to stop stray light as the eye relief is quite long.

I have to have my eye fairly well centered on the eyepiece and with a long eye relief, having the eyecup lets me gently rest my face in the right place.  I've got some lovely widefield views of M42 and the Pleiades, with the whole of the Pleiades fitting into the FOV nicely.  I can confirm that the diagram that astronomy.tools produces is fairly accurate:

I'm really quite impressed and for the sake of about 30 GBP, it's worth a go.  No issues with CA or astigmatism, sharp views across most of the FOV, etc. and definitely confirms that I like 2" eyepieces in general.  Will be trying this with some smaller binoculars in the future!

Edited January 10 by GrumpiusMaximus

[Louis D]

Please post a pic of what you came up with.  I'm curious now.

[GrumpiusMaximus]

46 minutes ago, Louis D said:

Please post a pic of what you came up with.  I'm curious now.

A slightly rubbish picture of the setup I took about 20 minutes ago, after getting too cold.  I'll get a better one tomorrow.  The eyepiece is too big for this scope really and needs something with a longer focal length and larger aperture.  But scanning the Milky Way with it is great fun.

[Louis D]

Not bad looking for a first effort.  It might also work well in a Mak with a 2" visual back to get to a large exit pupil for use with a nebula line filter.

[Chaz2b]

I’ve just bought a couple of Vivitar MC Tele Converters 2x-22. These are now my barlow 2x and were less than a tenner for both. I’ve still to make and fit the eyepiece receiving tube.

chaz

[GrumpiusMaximus]

Some pictures of the completed eyepiece.  I actually used three pairs of binoculars for this for various reasons but one of them didn't have a metal lens cell, so the top lens is just the lens without a surrounding, secured with a metal collimation ring.

[Louis D]

Tinkering with optics is a lot of fun, isn't it?  I've got several finderscope projects in various levels of completion myself.

[GrumpiusMaximus]

18 minutes ago, Louis D said:

Tinkering with optics is a lot of fun, isn't it?  I've got several finderscope projects in various levels of completion myself.

Even more fun when you have no idea what you're doing!

[Louis D]

15 hours ago, GrumpiusMaximus said:

Even more fun when you have no idea what you're doing!

But quickly enough, you learn what works and what doesn't.  It's sort of how SpaceX was run at the outset.  They didn't know what they were doing to start with, and look at them now.  Trial and error hopefully leads to success eventually.  As Edison (sort of) said about his light bulb failures, "I have not failed, but found 1000 ways to not make a light bulb."

[graham56]

i had a go the red henry way 4 50mm achromats , super sharp to 95% off the field , produces 5 deg field in a tak fs60c 

 

 

 

[LondonNeil]

That looks very smart,  if it works as good as it looks then we'll done indeed!

[graham56]

yes it does work remarkably well its made with , 4 50mm objectives from 2 pairs off 10x 50 binoculars off ebay (£35) the casing was made by in my fab shop (sheet metal worker by trade), so it functions greats and looks good its even threaded for 2" filters

[LondonNeil]

Good effort!  Its something to be proud of!

Have you tried it much yet? Is it in the 'its pretty decent for £35 and was lots of fun to make' bracket or are you now the proud maker and owner of optics norm costing considerably more?

[graham56]

its similar  to a 56mm a meade 56mm smothside plossl i once owned but with better eyeplacement , the other eye lens off the bins make good 1/1"4 eyepieces a lot better than entry level eyepieces supplied with entry level telescopes.

and yes l have only tried it in  my tak fs60c  which it performed very well i have a lot off better telescopes to try it in soon will keep you posted.

[GrumpiusMaximus]

That looks a lot nicer than my effort!  Exactly the same configuration in mine.  It's good fun, isn't it?

[LondonNeil]

We need an enterprising astronomer to sell some cases 😁  I imagine it could be quite simple for someone with a 3d printer. 

[graham56]

yes  it is good  fun , i have just picked up 2, 7x 35 binos  about to turn them into a eyepiece .  my personnel eyepiece collection is there  abouts complete (50) and yes acquiring . the lenses is easy, sourcing. eyepiece barrels isnt.