Thilter forts

[Demonperformer]

OK, confession time. I can feel myself being drawn down the astronomical razor-blade into the dark side. Can't afford it at the moment, but from what I have read, I suspect the way to go is a mono ccd camera with Ha, Hb, SII and OIII filters. With that in mind, I am starting to wonder if benefit can be gained from some of those filters without the aforementioned mono ccd camera.

Specifically:

* Do these filters provide improvement visually or jus ccd-ally? I keep reading that OIII filter makes nebulae much clearer. If so, such a filter may be a useful purchase on its own. Or indeed would it help me get piccies of the brighter nebulae on my modified webcam? Would the other filters also bring out more detail with the webcam? I suspect there would be problems because the webcam is colour?

* If I was to get an Ha filter and use it on the sun [also using my thousand oaks solar filter of course], would that give me some nice Ha views of the sun like the piccies we see of SGL without having to fork out for a coronado, or is that something completely different?

Thanks for your input.

[Whippy]

What you're talking about here is narrowband imaging. The filters you've mentioned let through very specific light frequencies that emission and planetary nebulae emit and nothing else. They're great for nebulae but pretty much useless for imaging anything else (with certain exceptions of adding Ha to galaxies for example). For me, the one big advantage with narrowband filters is that you can image while the Moon is about. You can still do mono or colour (with RGB filters) with a mono cam.

WRT the Ha filter and the Sun, you're right, it's completely different. The Ha filters used for imaging are different to the filters used in solar scopes.

Tony..

[RobH]

Hello DP.

As Tony says, the filters you mention are for narrowband imaging and are not suitable for visual use...they don't let enough light through.

Ha filters used in solar telescopes are completely different to Ha narrowband filters, and are a much tighter bandwidth....whatever you do, DO NOT use an Ha NB filter to try to look at the sun!

Smell of burning eyeball and all that

NB filters on a webcam won't work, because you need long exposures, typically 10 minutes or more unless you have a really big scope, due to the small amount of light they let through, and webcams aren't the right choice for long exposure imaging.

Cheers

Rob