What Do You Think Of My Home Made Solar Filter?

[Suzy]

Hi everyone

I believe this is my first visit ever in this section!
And I guess you're wondering what I'm doing here
Because let's face it, anyone that knows me well enough will tell you I'm useless at "making" anything. So hubby (Russ) does all the work for me on my scope as it benefits him greatly- because as I've said plenty of times before- he prefers me out of the house than in.

Please could you tell me if this solar filter he made is safe?
I think it's a pretty good idea that he came up with but as I couldn't find anything like it on the internet, I got a bit concerned whether it was safe.



Here's what he did on my 10" dob.....

He got two DVDs, measured and cut out the hole in it to make it bigger (60mm) using his Lathe (boys and their toys ).
He chose DVDs because he thought they'd be stronger and flatter than cardboard.

He then inserted the Baader Solar Film between the two discs. The film doesn't measure out to the full size of the disc- about half way out. He stuck sticky tape down across a 3 points on the disc to hold the disc sandwich together. It's nice and firm.

He then used a black marking pen to blacken the edge of the discs.

He then got the dust cover (the one that covers the tube) and drilled 3 holes in it and then inside the cover he fixed fly screen clamps to it.
The film is mounted inside the cover, sitting under the little aperture stop down cap.
The fly screen clamps keep the filter firmly in place.


My Questions:

(1) Is this safe?
Should I completely seal the outside of the disc with tape all around the discs?
I worry that there might be scattered light going out of the edge of the disc & reflecting back at me (even tho it's well sandwiched together).

(2) Is a DVD safe to use with this film?

(3) Today I gave it a quick whirl and I found the sun a bit bright but certainly not uncomfortable- I was a bit nervous not ever looking thru a solar filter before, so I don't know If that's normal or because of scattered light reflecting back at me.

(4) A couple of times I also got a purple tint on the sun- what would that be?

Boy my first view of the sun was fabulous- there were so many sun spots!! But I didn't view for long as I thought it best to check with you guys if my solar filter is a go-er!


Thank you to all that go to the trouble of helping me.

[astroron (Ron)]

Looks very professional to me Suzy.
There should be no stray light entering the telescope as far as I can see.
Good job.
Cheers

[mozzie (Peter)]

great job suzy!!!! very professional.....

as to is it safe...you'll be blind within a second if not no looks good just be very cautious while using it...

[Dennis]

Hi Suzy

Looks a nice job! Just check to make sure you used the Baader visual astro solar film, with an optical density of 5.

The other type of Baader film is the Baader astro photo film, with an optical density of only 3.8, which is designed to let a lot more light through, so that you can use high shutter speeds for photographing the Sun - it is completely not suited to visual use.

Under controlled conditions, with the Sun low on the horizon, I once had a very quick glance through my Vixen 4” refractor with a full aperture 3.8 film, just to centre the Sun in the FOV and it was very uncomfortable to the eye.

Cheers

Dennis

[michaellxv (Michael)]

Hi Suzy,

Looks like a good solution. I'd be a little concernd that the CD's may warp in time with exposure from the sun. Just keep an eye on that and check before each time you use it and you should be ok.

[Poita (Peter)]

The blank DVDs I have aren't completely light-proof, I can see through them a bit. Other than that it looks pretty slick. I tend to use a polarising filter and an IR blocking filter for solar viewing, I like the extra detail it seems to give, and the added protection of the IR filter.

[astroron (Ron)]

The only thing that I see will be in the Sunlight is the solar filter.
The CD's joined together to hold the filter material are in the inside of the telescope and in NO direct Sunlight, and are securely clamped to the inside of the cap.
Cheers

[Suzy]

Originally Posted by mozzie

great job suzy!!!! very professional.....

as to is it safe...you'll be blind within a second if not no looks good just be very cautious while using it...

Aaaaaaaaaaarghhhhhhhhhhh!!!!!
Not what I wanted to hear!
Naturally I got Russ to try out his workmanship by making him look through it first.

Originally Posted by Dennis

Hi Suzy

Looks a nice job! Just check to make sure you used the Baader visual astro solar film, with an optical density of 5.

The other type of Baader film is the Baader astro photo film, with an optical density of only 3.8, which is designed to let a lot more light through, so that you can use high shutter speeds for photographing the Sun - it is completely not suited to visual use.

Under controlled conditions, with the Sun low on the horizon, I once had a very quick glance through my Vixen 4” refractor with a full aperture 3.8 film, just to centre the Sun in the FOV and it was very uncomfortable to the eye.

Cheers

Dennis

Dennis I was hoping you'd see this thread of mine and make a comment- so thank you!
Yes, it's visual film.
I'm glad to hear the sun can appear bright and not something we've done wrong- that's such a relief! I think I'll pop on a moon filter or a coloured filter and see if it dims it down a bit. As I said before, it wasn't "uncomfortable", but just might make the viewing more comfy as I'll be seeing it on and off most of the day.

Originally Posted by michaellxv

Hi Suzy,

Looks like a good solution. I'd be a little concernd that the CD's may warp in time with exposure from the sun. Just keep an eye on that and check before each time you use it and you should be ok.

Hi Michael- long time no see!
That's a great tip you gave and I will definitely check regularly.
In fact Ron gave me another great tip today- seeing as the scope is going to be outside facing the sun most of the day and with that big dust cap being black (and absorbing all the that heat all day, and also that the dvd will be sitting under that cover, he suggested it'd be a good idea to cover the dust cap with alfoil (except for filter hole).
So as double measure, I will seal the dust cap all around with tape (black electrical) as usual, then put the alfoil on and then I'll seal that all around as well. I want double precaution for that tape not to come off as my cap tends to fall off a bit easily when it's pointed down, so I don't trust it one little bit.

Originally Posted by Poita

The blank DVDs I have aren't completely light-proof, I can see through them a bit. Other than that it looks pretty slick. I tend to use a polarising filter and an IR blocking filter for solar viewing, I like the extra detail it seems to give, and the added protection of the IR filter.

Hi Peter,
I see Ron set you clear.
Thanks Ron, nicely explained.
During my many reading sessions of safe solar observing, I did come across an article saying that dvds weren't recommended for use- I didn't even know that was even a possibility on an level!
Thanks for your tip re polarising filter- I'll try the moon filter or perhaps one of my colour filters (yellow perhaps) and see how I go. As we'll be observing it for quite some time, it might make viewing more comfy on the eye during such a long session.

[Nico13 (Ken)]

Hi Suzy,
Looks good.
I hope you have more luck with the sun than I am down here at the moment though.
Every time I step outside with my scope with solar filter attached clouds appear from nowhere

[scopemankit (Chris)]

Well done Suzy
If you find it too bright, tape another layer of the filter over the present one. Check the sun out, if it is a comfortable brightness Remake the device with double filter.