Baader solar film

[gsjag]

Guys (& girls),

If I put some Baader solar film at the end of my ETX and hold it on with the dew cover, does this mean that I can safely view the sun or is there more to it than that and I'll end up burning my eye balls out?

Thanks

Gary

[GordonCopestake]

I wouldn't HOLD it there with your hands, whilst technically this would work there is the possibility that the film might slip or the wind blow it away. You need to construct a snug tight holder for the film out of card or buy a ready made one.

BE VERY CAREFUL WITH SOLAR OBSERVING!!!

[gsjag]

Yes, appreciate the dangers involved (thanks for re-enforcing the message though), but in principle, as long as I can secure the film there is nothing else I need? Don't need to reduce the telescope's aperture or anything; just apply the film and go.

Excellent. Thanks Gordon.

Gary

[GordonCopestake]

nope, just the film. Dont forget that you will only see white light though not Hydrogen alpha. Even so, it's a sight to behold and you can observe in the warm

[gsjag]

That's great (with all the cloud there is at night I need to look at something)!

Thanks again Gordon.

Gary

[OXO]

Not to over do the Caution side of Solar observing(if one can do such a thing?) but when you have you Filter check for pin holes in the foil, this is something i did by holding it up close to a lamp(bulb) and noted there was many pin holes(around 50) which i Would never use just thrown it in the bin..Iam sure any astro dealer would of given me my money back or exchange but id made the mistake of cutting it first etc etc(doh!)

Worth a check, but the Badder Solar Film does have a fantastic reprotation and this should not put off anyone buying..

James

[GordonCopestake]

Again, make sure everything is safe before you risk your eyes, but that being said....

Just taken a couple of snaps for you

[GordonCopestake]

You can't really see anything in the second shot but you can see the colour the sun appears using the baader film. There is one sun spot i can see in the bottom right at the moment.

[gsjag]

Good point James thanks.

And thanks Gorden for taking the trouble of posting the pictures. Looks like a really nice setup you have there.

Gary

[daz]

Gary

Telescope house also do a range of ready made covers for your ETX, if your worried about making something.

You will be stunned with the view, and as with all things astro, aperture is King!!!

[gsjag]

Thanks Daz,

Can more aperture really be a good thing when looking at the sun? Just seems like there is more light than you could ever use and even a pin hole objective would be sufficient. 8)

Thanks for the tip on Telescope house though, just that they are a bit expensive.

[GordonCopestake]

Dont forget that aperture provides not just light grasp but also resolution. The larger your aperture the smaller the details you can resolve

[gsjag]

Never thought about it like that Gordon, but why then are the Coronado 'scope so small (at least they look small in the mags, I've never seen one in the flesh)?

[GordonCopestake]

The PST's are 40mm IIRC, they are a whole kettle of different fish though as they use Hydrogen alpha filters which are MUCH more expensive than the usual fair. 40mm is enough resolution in HA to see the prominences which is what most people look at (mostly because you can't see them with white light)

[gsjag]

I never knew that! Thanks Gordon, really appreciate your insight.

[FLO]

The larger aperture Coronados are noticeably better but I feel sure most of that is due to the improved filter that they use.

[daz]

Having looked through the PST and SolarMax (60mm, IIRC) I can tell that the PST is AMAZING and the SolarMax is REALLY amazing!!!

And you're right Steve, the filters are different. The SolarMax is <0.7 Angstrom whereas the PST is <1.0.

Now, you ask, what is an Angstrom? It's a measurement of things, in this case, the size of Atoms. An Angstrom is 10^-10 metres, and a Hydrogen atom is 0.5A is diameter. So, you can see the PST would allow atoms of elements of less than 1 Angstrom through, but the SolarMax would only allow atoms with a diameter of 0.7 or less through. The result? Better clarity of the solar image because the Hydrogen is not being 'diluted' with other elements.

At least, that's how I understand it.....

[Astroman]

Um, a hydrogen atom is ~10^-8mm in diameter. The 0.7, 1.0 or 0.5 Angstrom specs refer to the waveband of light being passed through the filter. In other words, a SolarMax filter passes a very narrow band of H-Alpha light only 0.7 angstroms wide.

[gsjag]

Just had a thought. Given that solar scopes are rather specialised and expensive, why not use a relatively cheap solar filter on a standard telescope, which will give safe broadband viewing, with a H-Alpha filter on the eyepiece? Surely it would give the same effect but at a much reduced cost?

[Astroman]

Not the same effect, as the "specialized" filters are very narrow band and the filter you'd use in an EP would be most likely a photographic filter and therefore much wider band. Yes, they both say "H-Alpha", and they are centered on that wavelength, but it's a matter of precision.

[gsjag]

Thanks Astroman. Sounds like a possible gap in the market though....

[Astroman]

Weeelllll, if you can develop a filter that's precise enough to isolate H-A, can screw onto an EP and cost ~$100 US, I'll buy one. Where do I sign? I'm afraid we'd need another breakthrough technology to make this possible. Take a look at my second solar talk for some detail on the current etalon technology. Because of the precision needed, and the quality of material used, the cost is high.

[gsjag]

Understand, thanks Astroman. I will certainly look at your presentation, sounds really interesting. As to having a go at producing something, well, nothing ventured and all that (but don't hold your breath)!

Thanks again

Gary