DIY Solar filter for binoculars

[shelby90]

Hello,

I want to make some solar filters for my pair of 15x70 binoculars. I have heard of a material called mylar, which seems easy enough to purchase. However, I'm unsure about how to mount them. I would like to use a nice metal cell to fit the mylar into that can then fit snugly onto the end of my bins, but not sure where I would get that. Or I've thought it could be easy enough to just buy a couple sheets of the mylar and use rubber bands to secure them onto the ends (not the eyepiece end, I know). Maybe just purchasing a ready-made filter would be a better way to go. I've seen glass filters but they are expensive, but also seem more durable.

If anyone has personal experience making a pair of solar filters for their bins or their telescope, I'd be happy to have any advice on how you went about making them.

Thanks!

[Peter Drew]

I made some solar fiters for a 10x50 binocular by cutting holes in the objective cover caps and covering them with solar film. Attaching film to the front of the binocular with rubber bands works ok but involves a lot of fiddly handling of the film which it doesn't like. 

[Dr_Ju_ju]

Hi Shelby,

From the site sponsers', http://www.firstlightoptics.com/solar-filters/baader-astrosolar-safety-film-nd-50.html

The Baader film & range of pre-made solar filters is just about the 'standard' for us in Europe.

I've made multiple filters using it, simply by sandwiching the film between pieces of card, that is then fixed FIRMLY to the optical tube.

Standard warning NEVER EVER look directly at the Sun....

[JamesF]

If you buy the Baader solar film (which is arguably the best, but watch out for the clear protective sheet on one side), there is a set of instructions included for making card mounts for the film.  There are also a few posts in the DIY section by people who have made their own mounts for bins.

When I made my last set I made the mount from various bits of plastic I had lying around which is perhaps a bit more robust and looks neater.

In your case I think I'd be tempted to look for any sort of can, plastic jar or cup etc. that might be a reasonable fit over the end of the binoculars and cut them up as required.  If they're a little loose then some self-adhesive felt can be useful for lining the inside.  I'd also add some sort of lanyard or loop of elastic that can hold the filters in place so there's no way they can fall off.

James

[shelby90]

I made some solar fiters for a 10x50 binocular by cutting holes in the objective cover caps and covering them with solar film. Attaching film to the front of the binocular with rubber bands works ok but involves a lot of fiddly handling of the film which it doesn't like. 

Ah, yes I suppose I wouldn't want to ruin the film by messing with the rubber bands all the time. The objective lens cover is definitely a nice idea. I already know that they fit over the objectives so I'd just have to cut circles and tape some film in there. Thanks!

Hi Shelby,

From the site sponsers', http://www.firstlightoptics.com/solar-filters/baader-astrosolar-safety-film-nd-50.html

The Baader film & range of pre-made solar filters is just about the 'standard' for us in Europe.

I've made multiple filters using it, simply by sandwiching the film between pieces of card, that is then fixed FIRMLY to the optical tube.

Standard warning NEVER EVER look directly at the Sun....

I've seen some videos and instructions on making filters with cardboard, which seems super easy. I've read that the Baader film keeps the Sun looking like its natural white color versus some other brands that give either a blue or orange tinge. Is that your experience? Thanks for the input!

If you buy the Baader solar film (which is arguably the best, but watch out for the clear protective sheet on one side), there is a set of instructions included for making card mounts for the film.  There are also a few posts in the DIY section by people who have made their own mounts for bins.

When I made my last set I made the mount from various bits of plastic I had lying around which is perhaps a bit more robust and looks neater.

In your case I think I'd be tempted to look for any sort of can, plastic jar or cup etc. that might be a reasonable fit over the end of the binoculars and cut them up as required.  If they're a little loose then some self-adhesive felt can be useful for lining the inside.  I'd also add some sort of lanyard or loop of elastic that can hold the filters in place so there's no way they can fall off.

James

Great suggestion about the jar or cup. I've found a few jar caps around the kitchen that could work really well. With a little styrofoam or felt taped to the inside to make a snug fit, it could work really well. Thanks! I'll take a look at the other threads, too.

[Dr_Ju_ju]

Hi,

Yes, you are correct in that the cheaper filters are yellow in colour, but also be aware that there are 2 main types of Badder film, an ND 5.0 for visual use and an ND 3.9 for photographers ONLY.

[Bizibilder]

Baader film is very good.  However I do not recommend using rubber bands to hold it in place!  The film will be damaged if you crease it.  As suggested make a holder from either plastic or card and use that - you only need to make one if you like but make sure the other lens cap is taped in place so it cannot fall off!!!  The film can (and usually is) somewhat "rippled" when put in a card holder but this is of no consequence - you must not "stretch it tight" or you will damage it.  Having told you how easy it is to damage. I must add that when properly handled it is very tough indeed.  Keep your filters in a container so they can't get scratched or damaged and they will last you for years.

[Alien 13]

The solar filters can be made slightly smaller than the actual objective size which can make it easier to secure in place. With my scope I cut two pieces from an old DVD case and sandwiched the film between them then mounted it all in a tight fitting tube.

Alan

[shelby90]

Hi,

Yes, you are correct in that the cheaper filters are yellow in colour, but also be aware that there are 2 main types of Badder film, an ND 5.0 for visual use and an ND 3.9 for photographers ONLY.

I was not aware of that, so thank you for the info!

Baader film is very good.  However I do not recommend using rubber bands to hold it in place!  The film will be damaged if you crease it.  As suggested make a holder from either plastic or card and use that - you only need to make one if you like but make sure the other lens cap is taped in place so it cannot fall off!!!  The film can (and usually is) somewhat "rippled" when put in a card holder but this is of no consequence - you must not "stretch it tight" or you will damage it.  Having told you how easy it is to damage. I must add that when properly handled it is very tough indeed.  Keep your filters in a container so they can't get scratched or damaged and they will last you for years.

I was wondering about the rippling, since all the pictures and videos I've seen show the finished product to have some slight rippling, but good to know it doesn't affect the observing. And I did read to certainly NOT put tension on the film as it deteriorates the quality, so good to have that reiterated. Thanks 

The solar filters can be made slightly smaller than the actual objective size which can make it easier to secure in place. With my scope I cut two pieces from an old DVD case and sandwiched the film between them then mounted it all in a tight fitting tube.

Alan

Very nice idea. The DVD cases seems like a very strong option. I like the idea of making them slightly smaller than the objective as there isn't that much room between the two tubes of the binoculars. It would be a bummer to make one side only to realize the other side doesn't even have the room to fit on! Thanks for the input!

All very helpful info 

[Alien 13]

This is a useful guide http://www.baader-planetarium.com/sofifolie/bauanleitung-objektivfilter-en.pdf

Alan

[shelby90]

This is a useful guide http://www.baader-planetarium.com/sofifolie/bauanleitung-objektivfilter-en.pdf

Alan

Thanks so much! By the way, I love your avatar picture--reminds me of my dog that passed away a few years ago 

[michael.h.f.wilkinson]

Another +1 for Baader film. Watching the sun through binoculars is great fun.

[michael8554]

Hi shelby90

Just to be absolutely clear, all the above posts have steered you towards the Baader Solar Film.

IF YOU VALUE YOUR EYESIGHT YOU MUST NOT USE THE ORDINARY MYLAR THAT YOU SUGGEST IN YOUR FIRST POST.

Perhaps you meant the Baader film, if so No Problemo.

Michael

[shelby90]

Hi shelby90

Just to be absolutely clear, all the above posts have steered you towards the Baader Solar Film.

IF YOU VALUE YOUR EYESIGHT YOU MUST NOT USE THE ORDINARY MYLAR THAT YOU SUGGEST IN YOUR FIRST POST.

Perhaps you meant the Baader film, if so No Problemo.

Michael

You know, it's funny, I do value my eyesight   When I first posted, I didn't know much about any solar film, but the message seems to be loud and clear that Baader is the best way to go.

Thanks for the help everyone. I haven't gotten around to making them yet, but the advice has been very useful.