Is it safe?

[rfdesigner]

I have recently taken posession of a narrowband filter set.

It occured to me that I could use the Ha filter to look at the sun.. WITHOUT THE SCOPE, just take a peek and see what's there, maybe pick out a solar flare.

It might be a great thing to show my daughter too.

at only 7nm wide.. and blocked well into the high IR is this safe to do?

Derek

[JB80]

NO don't do that!

It is not the right type of Ha filter, it wont work and will be very dangerous.

You can use it with baader solar film for white light imaging but you need to have that blocking protection, and you wont see any flares.

[stem1989]

in a word no! always get the right equipment when it comes to the sun. Theres no room for error really.

[DirkSteele]

As already stated, definitely NOT safe. Solar scopes, including Hydrogen-Alpha also use an energy rejection filter. When it comes to the Sun, and your eyesight, take no chances.

If you really want to see the Sun in H-Alpha, the cost of entry is far lower than it use to be thanks to solar scopes like the PST.

[rfdesigner]

Thanks, not doing it!

Derek

[Naemeth]

As I understand it, the problem is not the colour (or wavelength) of the light coming through, it's the heat from the sunlight. If the Sun can easily burn mist in the atmosphere, think what it can do to your eyes or camera!

[JamesF]

I'd assume the real issue here is that whilst the Ha filter may block most of the visible spectrum, or indeed most of the spectrum to which camera sensors are sensitive, you may still get a lot of energy passing through the filter in the Ha band and in the higher energy non-visible wavelengths that may be damaging. There's also the possibility that the filter may not be totally opaque to the visible wavelengths either, but works sufficiently well for it's intended application not to be an issue. Asking it to stop all (other than the Ha) visible light from an object as bright as the Sun might be asking way too much of it.

James

[rfdesigner]

Just located the 'safe limit'

turns out it's 0.0032 percent, and 0.0003 for comfort. So a Ha filter passing approx 1% of the light is allowing about 300x too much light just to be safe and 3000x more than comfortable

Ouch!

[Pig]

Just a tad too much then

I thought I was hallucinating when I read you were going to get your daughter to try it

This cannot be a serious post -

[rfdesigner]

It's been so long since I've seen the sun I've forgotton just how bright it is

[DaveS]

Many a long year ago when I was young and foolish I built a spectroscope with quite a wide dispersion and thought I'd have a look at the solar spectrum by projecting the image from my 60mm 'scope on to the slit. Even though the slit was very fine and the dispersion very wide it was still too bright, and although it didn't blind me that eye still has a slightly yellower colour rendition to the other. I could actually see the H&K lines very clearly, there was so much light.

What is worse it that it's my dominant eye and is still opticly better than the other.

I think I got off lightly, all things considered.

DON'T TAKE CHANCES WITH THE SUN!

[OutThereSomewhere]

What are h&k lines?

[OutThereSomewhere]

Ah, just googled the term and i'm going a bit off topic by asking so please forget my post