Checking and performing conditional collimation using Bahtinov masks!

[Psychobilly]

You already have the focus aid with The bahtinovs... ;-)

I really need to get my 25x100s sorted maybr a job for crimbo week...

When I was getting Bahtinovs laser cut I had looked at getting them printed or vinyl cut snd laminated as a lower cost option... Glad it worked for you

Peter...

[pleiades]

Heck, it is boring cutting out the slits on a Bahtinov! Did one this arvo, and nearly lost the will to live. I think I might get some inkjet transparency and see if that works instead...

First I like to thank you Steve for the great idea you have to use inkjet transparency!!! I didn't tried it yet but this was my purpose when I first asked if we can find any improvements in the procedure. Collaboration is a great thing.

used a distant street lamp a couple of hundred metres away, binoculars on a monopod. Because the streetlight is a relatively large extended object, the diffraction spikes aren't as crisp as with a star (or Jupiter), so it's impossible to estimate the degree of misalignment

Yes, you have right. As I can see if we want to test with a street lamp must be hundreds meters away and strong, so to be as crisp as it can and create spikes.

But never will be as good as a star.

I can confirm what Konstantinos (pleiades) has said, i.e. that it is probably impossible to "force" the centres of the spike-patterns into alignment if there is miscollimation. If a binocular is degrees out of alignment, anyone with two working eyes can tell. If it is within standard tolerances, miscollimation is not a problem. In between there is a "miscollimation zone" where we can "force" the images to merge, but where doing so causes eye-strain, followed by headaches, tiredness, or nausea (or some combination thereof)

Those are good news! Your description is very accurate Steve. Of course because I am a little "sensitive" with miscollimation and usually I spend hours in observation, I am trying to fix also small misalignments to avoid fatigue. But this is something personal and everybody can have different tolerance in miscollimation.

I'd like to do this more rigorously under stars, and to miscollimate the Strath 15x70 again and see how easy it is to get good conditional alignment.

Konstantinos, I think you have hit on something valuable here; I think it is your privilege to give the method a name of your choosing

To tell me how easy is the conditional alignment with the "crossed Bahtinov" technique will be a precious information. For me is easy to align my binoculars this way, and I hope also to be for you all.

As regards the name I thing you have already found a descriptive name better than I can!

What we need next is a focus aid so you know when your focus is spot on...and a pair of bins with a crayford slow mo focus knob!

Mark

Mark, Peter (Psychobilly) has right. I use Bahtinov mask when I test binoculars. Before some days I tested an Helios Quantum 4 20X80. I found a matter with the width of focus, and was not easy to tell if I was at the right focus for the test. Using a Bahtinov the problem solved easy.

Thank you all for the time you have spend already to this. I will be glad if somebody else will try it and review it.

[pleiades]

I can confirm that it also works with inkjet transparencies. It took me only one minute to cut the outside with scissors.

Brilliant idea!

Thank you again Steve for the advice

[BinocularSky]

So much neater tabs than mine! Being a cheapskate, I printed 2 each of 100mm, 70mm, 50mm and 42mm on one sheet of A4.

[chuckinnc]

I can't locate any adjusting screws on any of my bins, only ones I can see are on the metal strap that holds the prism down. I assume that if

you don't have the tilt adj screws then there is no way to reallign the bins?

[pleiades]

Where the adjusting screws are?

Pick up a little the outside material to uncover the screws.

Use a jeweler's screwdriver.

 

 

Celestron Skymaster

 

 

Helios Quantum 4

 

 

United Optics BA8 (Helios Apollo, APM HD, TS Marine, Oberwerk Ultra etc) * Do not touch the screw marked with the yellow circle.

 

 

Image on top, the screws on Vixen Ultima 9x63

 

 

Nikon Action (hex key, Allen key)

 

 

Bresser 10X50 (Lidl)

 

 

As you can see most binoculars has the screws in the same position.

Do you have more pictures to upload?

 

 

 

[StevieDvd]

I can't locate any adjusting screws on any of my bins, only ones I can see are on the metal strap that holds the prism down. I assume that if

you don't have the tilt adj screws then there is no way to reallign the bins?

Some collimation is done using 'eccentric rings', though check carefully for this before attempting. It involves removing the protective ring around the object lenses and re-positioning 2 rings which aim the lens.

Better to see this page Sun Images Method for Collimation of Binoculars - rchamon which explains far more than I can.

An old pair of Russian Kronos 20x60 were completely out of collimation so I had a bash as they only cost me £25. Cleaned up and collimated they are quite good now, but heavy

But as I say don't go blindly removing the object lens, check for you binocular make/model first.

[pleiades]

Some binoculars like Fujinon, use 'eccentric rings' for collimation.

Some older, use screws which lay inside the prism compartment. Find the adjustment and the fix screws. More:

 

 

But usually at most binoculars the adjusting screws are outside of the barrels.

[Umesh]

Hello,

I am having some problems with my Garrett Gemini 20x80 LW collimation, I would like to try your trouble shooting method, but I do not know the focal length of this binocular.

Any idea on how to find this parameter?

Also on the web page you referred for generatin the bahtinov mask, there is edge thickness parameter which is by default 15mm on the page, should that be altered or left alone?

Please let me know!

Umesh

[BinocularSky]

I am having some problems with my Garrett Gemini 20x80 LW collimation, I would like to try your trouble shooting method, but I do not know the focal length of this binocular.

Any idea on how to find this parameter?

If it's for generating a Bahtinov mask, assume f4.5 (360mm focal length) -- it'll be close enough.

Also on the web page you referred for generatin the bahtinov mask, there is edge thickness parameter which is by default 15mm on the page, should that be altered or left alone?

It;s teh thickness of the rim around the objective lens. It's OK to leave it alone.

If you print out the mask onto transparency film, it works well enough and saves a lot of cutting.

Another thing you can try is a different coloured gel (or cellophane sweet wrappers) over each eyepiece. Does a similar job.

[michael.h.f.wilkinson]

What a neat idea. I should try this.

[Umesh]

If it's for generating a Bahtinov mask, assume f4.5 (360mm focal length) -- it'll be close enough.

It;s teh thickness of the rim around the objective lens. It's OK to leave it alone.

If you print out the mask onto transparency film, it works well enough and saves a lot of cutting.

Another thing you can try is a different coloured gel (or cellophane sweet wrappers) over each eyepiece. Does a similar job.

Thank you Steve, that clears my doubts about bahtinov mask.

Umesh

[Umesh]

Hello All,

I just finished collimating my Garrett Gemini LW 20X80, it had a major collimation problem. The images were offset vertically and horizontally. This technique of using bhatinov mask is very very effective as Konstantinos has already explained so well, I never expected it to be soo easy to collimate.

I had same issues with my skymaster 15x70 before and had struggled a LOT to collimate them. Wish I had read this thread back then, would have made my life so much easier.

Anyway, I was able to collimate my 20x80 in less than 10 mins, that too the skies were not very clear, i focussed on jupiter as the stars were not bright enough.

This is one of the best or I should say THE only way to collimate without having to go through any pain in the neck.

I am very happy

THANK YOU SO MUCH KONSTANTINOS!

Best Regards,

Umesh

[Umesh]

Hello All,

I just finished collimating my Garrett Gemini LW 20X80, it had a major collimation problem. The images were offset vertically and horizontally. This technique of using bhatinov mask is very very effective as Konstantinos has already explained so well, I never expected it to be soo easy to collimate.

I had same issues with my skymaster 15x70 before and had struggled a LOT to collimate them. Wish I had read this thread back then, would have made my life so much easier.

Anyway, I was able to collimate my 20x80 in less than 10 mins, that too the skies were not very clear, i focussed on jupiter as the stars were not bright enough.

This is one of the best or I should say THE only way to collimate without having to go through any pain in the neck.

I am very happy

THANK YOU SO MUCH KONSTANTINOS!

Best Regards,

Umesh

BTW I printed the masks on transperancy sheet, as Steve suggested. Thank you Steve!

[michael.h.f.wilkinson]

Neat stuff, must give it a try.

[themos]

I will print out some crossed Bahtinov masks as soon as my transparencies turn up, later this week. Until then, I can share my experience with my laser-pointer-assisted binoculars. They are the Revelation 15x70, also known as the  Kunming United Opritcs Corp. BA1 15x70  which are mounted on a mirror mount made by ScopeTeknix. I have added a green laser pointer so that I can see the laser beam both in the binoculars and with naked eye, to help with accurate pointing. Last night, I was trying them out when I realized, with this thread's information fresh in my mind, that I could use the appearance of the laser beam to achieve the same thing without the Bahtinov masks. I mount the laser between the objectives so the view in each eyepiece is different when the laser is on. Due to the intensity of the laser, that difference is quite pronounced and so acts to inhibit the brain's "auto-merge" which means I can detect the miscollimation quite easily. I will compare the two methods and report back.

[pleiades]

Hi Themos! I'm glad you are trying a comparison between different methods and test them.

I had experimented with laser beams for collimation in various ways, and also in the manner you describe. Try it out and when finish tell us about the results, so I will describe my experience with laser beams in the past, and the effort for conditional alignment through them.

[FLO]

What an excellent idea!

I hadn't noticed this thread until today (it was much easier back when SGL only fifty members!) 

I'll have a chat with Keith at StarSharp Bahtinov focus masks. It should be a simple thing to produce them in pairs, one at 90-degrees to the other. 

Steve 

[edjuh]

For those with a 3d printer, or the urge to have one printed, there is a bathinov-mask on thingiverse, which you could adapt for the exact opening of your binocular.

No need to hang it on the bino with ductape. The real advanterous might even extend the design with a funnel, (like a dewcap). Or even make it a dual-mask,

if the surface of the printer is that large you could even use them for that huge fujinon.

[stargazerslivingroom]

Just stumbled on this thread....Excellent!

So glad I found it

Steve

[EricFRP]

Konstantinos, thanks for this 'easy to use' collimation method I will apply ASAP (my binoculars need it)...

But does anyone know where the collimation screws are on the Miyauchi 100mm (BJ100RB model)?

I guess they are inside the binoculars which would maybe lead to loose the Nitrogen filling (not a big issue for me) but I would like to be sure.

Any experience and info collimating the 100mm Miyauchi binoculars?

Thanks

Eric

[pleiades]

You are welcome Eric!

About Miyauchi 100mm collimation screws, must be inside the binoculars below eyepieces as APM 100mm binoculars. It's not very difficult to align them. You just have to open one eyepiece at a time, adjust screws and cover with the eyepiece again to check the alignment.  I am not sure if you will lose the Nitrogen filling. Any way the best thing will be to give us a report about it, and take and upload here some pictures, to help others.

[SnakeyJ]

Very interesting thread and method - thanks Konstantinos.    I shall print up some masks for my own, rather old and travelled bins and have a go.

[szabi]

Hello.

Unfortunately the photos in the original post describing the exact procedure of collimation are lost.

Does anybody have them saved, and maybe could reupload? I'm not 100% sure how to use this method to collimate my 10x50 Carl Zeiss Jena binculars.

Or maybe some pictures, or youtoube vidoe on how you do the collimation would be very helpful.

Thank you.

[Grant]

The original images were hosted outside of the forum software in 'ImageShack' and have since been removed which is why the links are dead. The only way they can be reinstated is if the original author still has a copy and can re-upload them.