DIY solar filter

[Moonshane]

Hi all

I finally gathered the bottle to make and use a solar filter.

I robbed the design from Paul (piece of Mars man!) at PSP 2012 (thanks matey) and it works really well. It's basically two rings of card to match the aperture and used as the bread in a Baader solar film sandwich. I then made a tube to fit the scope aperture - I was making a 6" full aperture mask to fit both of my OOUK newts.

I then stuck/taped/glued, the rings about halfway down after cutting a notch for my Telrad base.

Finally, I had some spare flocking from FLO and used this to cover the whole thing for more aesthetics than anything else.

It fits quite snugly but I am leaving nothing to chance so added a couple of hole punched holes for elasticated loops to wrap around the focuser and 'dob knob' to ensure there's no way it can ever blow off in the wind etc.

Here's a couple of pics.

[kenmyers]

That is very nicely done.

Where did you get the paper from? and can you look through the eyepiece with this on the end of the scope or do you project it still?

I have been thinking about making one myself.

[RikM]

That does look very nice indeed. I have one made from a Shreddies box so it's a bit more *flamboyant* than yours.

Do you think you get noticeably better resolution from the full aperture? I used a similar construction for my 6" but I just have a 70mm off axis filter. Being such a cheapskate, and with the Baader film being so thin, I figured I could make 5 of the things from one A4 sheet. It seems to work very well so if your full aperture version is better, it could be time for an upgrade.

[Moonshane]

That is very nicely done.

Where did you get the paper from? and can you look through the eyepiece with this on the end of the scope or do you project it still?

I have been thinking about making one myself.

hi Ken

Yes, with the Baader solar film (obtained from FLO First Light Optics - Baader AstroSolar Safety Film ND 5.0) I look through the telescope as normal.

It's really easy and as long as you make sure the film (or card) covers the whole viewing aperture with no gaps and cannot come off, then it's safe too.

[Moonshane]

That does look very nice indeed. I have one made from a Shreddies box so it's a bit more *flamboyant* than yours.

Do you think you get noticeably better resolution from the full aperture? I used a similar construction for my 6" but I just have a 70mm off axis filter. Being such a cheapskate, and with the Baader film being so thin, I figured I could make 5 of the things from one A4 sheet. It seems to work very well so if your full aperture version is better, it could be time for an upgrade.

ha ha

I reckon I'd have used black paint if I didn't have some flocking left.

I cannot really say about the smaller aperture other than my memory suggests the view through my 6" f6 is better than a WO Z66 refractor with full aperture that I looked through recently.

The detail was surprisingly good and I am looking forward to trying it with my 6" f11.

[arbacia]

Just a point about safety:

Use some string or velcro or whatever to strongly hold the filter to the telescope. A gust of wind could blow away suddenly the flter and that is extremelly dangerous for the observer.

[Gina]

Absolutely!! I prefer to use a camera. I know the Baader filter is supposed to be safe if careful precautions are taken but I value my eyesight to the extent that I'm not prepared to take the slightest risk (as must apply to all astronomers).

[JKB]

Absolutely!! I prefer to use a camera. I know the Baader filter is supposed to be safe if careful precautions are taken but I value my eyesight to the extent that I'm not prepared to take the slightest risk (as must apply to all astronomers).

Yeah couldn't agree more! Although I would love to look at the sun I'm just too scared to take the risk. Dunno why but just am.

It's a bit like taking drugs. I would love to know what they did/make you feel like but wouldn't as I'm too scared of the consequences. I'm sure in the right hands and following appropriate measures the solar filters are fine but think I would rather trust a dedicated solar scope?

Just my 2p's worth

Cheers

Jamie

[nightfisher]

nice job shane, no point in me doing this job, im yet to finish my "shreddies box" aperture mask for my tal 100, and like others im a bit of a scardy cat when it comes to solar viewing

[arbacia]

The baader film is safe. I have been using it for years. In fact, I made a number of cells. My previous message was only a reminder about the installation of some mechanism to hold safely the cell to the telescope. A simple cord or velcro is enough. Be carefull with adhesive velcro or tape as them with the heat of the sun can detach.

Patricio

[Moonshane]

I am also a scardey cat. That's why I made the cell out of card/paper, with the film glued between two circles, then taped and glued into the tube which is stapled and glued and then used more layers of papers and tabs also glued in before adding the flocking.

I also added a couple of tight elastic cords to go round the focuser to the tight fitting filter tube.

I am also taking no chances - also important, store it in a hard cardboard or plastic box.

[arbacia]

I also added a couple of tight elastic cords to go round the focuser to the tight fitting filter tube.

I am also taking no chances - also important, store it in a hard cardboard or plastic box.

Perfect!!!

[Merlin66]

Observing the sun is safer than driving a car!

Sure, you can drive irresponsively - crash and burn!

same with solar observing - use the proper filter, correctly and you'll enjoy 100% safe viewing of our nearest star.

Try it - you'll love it.

[RikM]

I also use a sturdy elastic strap to hold it in place and store it in a cardboard box when not in use.

[todd8137]

looks goodi would like to try this on my 12" but it means take in a smaller view,i might try and leave the film square and cut the support to fit,this may seem odd but if i used a web cam at the ep (to scared to eye view) can you use filters on the web cam to give dif views?

[Merlin66]

You only really need a UV_IR filter on the webcam. Adding a green filter will further improve the contrast. That's about it.

[Gina]

If you use anything but a circle for the filter you may get diffraction spikes. You can even see them at time with an ordinary camera (eg. DSLR) under certain conditions from the camera iris if stopped down.

[Merlin66]

Gina,

Not sure you'd see them viewing the Sun in white light ;-)

[Gina]

I'm not sure either. Try it and see I guess. I think you only get interference spikes on virtually point objects. I'm trying to remember when I've seen them

[RikM]

Do you still need the UV/IR blocker with a Newt?

[Merlin66]

Hmmm

Probably not.

The Baader solar film has a small IR leakage which seems to affect imagers; giving a slight loss of definition. Any likely hood of this problem would be removed with the UV-IR filter.

[kenmyers]

One more question,

Is it possible to double layer the film (twice the protection from pinholes?) or would this block all light?

[pete_l]

One more question,

Is it possible to double layer the film (twice the protection from pinholes?) or would this block all light?

Pinholes aren't a big deal. The light that does leak through a pinhole is dispersed and its intensity won't harm you. If you want, you can check that - get a piece of paper, pr ick a hole in it and hold it up to the sun. You won't go instantly blind!

As for "double bagging" the film - if you get a hole in one layer, it's more than likely that whatever made that hole would penetrate both layers.

[Merlin66]

There's no need to "double layer" - it works OK.

[RikM]

Baader film is coated on both sides anyway so the likelyhood of defects on each side 'lining up' is very remote.