Narrowband Project

[Ant]

Morning all.

I've been chatting with a few people about the lack of good information on the net (in one place) on the NB suitability of objects.

Obviously Emission nebulae generally respond well to NB, but which ones... are there any others? M82 has some great Ha data as does a number of other objects.

I started taking a few images the other night just to get my idea across

After chatting with Martin, to be most useful the data through each filter should be the same length and stretched to the same degree...

After Guy's (Coco) comments >>here<< multiple stacked subs will probably work best and he is right.

But at least to start with as we build up the library one sub in each will give a starting point.

So what NB images have you got - or more importantly what NB images have you got where you still have the unstretched subs for?

I plan to collate all of these images and have a locked reference thread on SGL - I think it'll be the first of it's kind anywhere...

Cheers

Ant

[foundaplanet]

What a fantastic idea. I look forwards to seeing some more.

Nice one, thank you.

[Ben Ritchie]

Obviously Emission nebulae generally respond well to NB, but which ones...

"Respond well" isn't quite the right way of putting it - emission nebulae ARE narrowband objects, in that their line emissivity is high.

In contrast, reflection nebulae are poor narrowband objects, as the bulk of what you see is broadband thermal emission (i.e. quasi-Black Body) from stars reflected off dust.

are there any others? M82 has some great Ha data as does a number of other objects.

Most spiral galaxies are star-forming, and will show strong H-alpha emission from star-forming regions in the arms (e.g. those clumps in M33). Interacting galaxies generally have intense star formation and hence are strong H-alpha emitters (e.g. M82). There is other forbidden emission there too, but it tends to be much weaker than for emission nebulae, so as a rule of thumb i'd say galaxies work best as a H-alpha/LRGB blend of some sort, rather than as pure narrowband objects. Most of the emission is still broadband thermal from stars.

Elliptical galaxies are generally not star forming, and therefore poor H-alpha emitters.

I plan to collate all of these images and have a locked reference thread on SGL - I think it'll be the first of it's kind anywhere...

Personally I think that rather than try and enumerate everything that works, it might be better to look at why it works - I find there's an awful lot of misunderstanding about what narrowband imaging means. I wonder if someone (Ken?) has spectra of a few, as it explains a lot. Most of what I have is of emission line stars, which are somewhat different.

[Ant]

I've made a start on how I see it working. The information may or may not be correct at this time...

This is me just getting things together in my mind - so this is likely to change. But this is the sort of thing that I had in mind.

Astro Imaging in the UK click on the link top right that says narrow band project.

This is the summary page as it currently stands, NGC 281 is at the top (but that's because this is the only one that I;ve got any data for) of the list - it will eventually be in the NGC list...

Thanks for the reply Ben, why these things work and emit the light that they do would be very interesting - but that's not what I'm trying to do here.

If you want to put something together I'm sure that there will be loads of interested readers. I'm hoping that the new software will have a good CMS and articles like that will look really good.

Cheers

Ant

[Stephen]

Good idea

[SlipperySquid]

I have a few images that I have single subs for. What is it you actually require mate?

Matt.

[Ant]

narrow band images of objects (single un-stretched subs would be best). Any object at the moment....

Any that you have stick'em through to ant@emberson.org

Cheers

Ant

[SlipperySquid]

JPEG format?

Matt.

[Ant]

Hi Matt,

If they are un-stretched then a fit would be better (if size is an issue for your email then you can re-size to 500 x whatever.

I can then stretch them all to the same degree

Cheers

Ant

[swag72]

I think this is a great idea as I was wondering what targets were good for narrowband imaging. It will be excellent to see what you can expect to see with eacg sub as well.

@Ben Ritchie - That is a very good description, than you for making that so clear.

Thanks Ant for looking at collating this - Top man!

[Keiran]

I think this is a great idea mate... cant wait to see what you put together.

I like the way you put them all together at the top. Give people an idea of what they can expect to get, and what bits of info make up different bits of the image... Just a suggestion, can you link the final image so it can be seen in a larger size?

[Ant]

For the first stage of the keiran that's not going to be possible. I am only asking for small one sub images. So I do not have the hi-res image to link to...

But in time I think that could be a great idea. People could submit a single unstructured sub along with a finished (multi sub/channel) image.

Cheers

Ant

[NickK]

Surely sharing 16bit FITS images would be better?

[NickH]

I have found that some comets work very well in OIII and SII filters, the OIII in particular, combined with a standard CLS and SII gives very interesting results.

[Ant]

Hi Nick,

These images aren't for sharing as such - certainly not images for combining into a hubble pallet finished image.

This project is to just show what of the four main (Ha, OIII, SII and Hb) narrow band lines is in objects.

So if anyone has any narrow band fits - preferably sets (ha, OIII, SII and maybe Hb) of the same exposure length then if your willing - email them over to me.

As this project is only at the start, any narrow band images will be great - does anyone have fits of mono/osc of galaxies and then a Ha image (M82 looks great with Ha added).

Keep a track of where I've got up to >>>HERE<< I have some emails in my inbox that I haven't sorted yet.

Cheers

Ant

[NickH]

Ant, sure, am more than happy to share the FITS from the comet imaging. Will send via sendspace link. Have already passed over a lot to another member working on a stellar extinction project

[Penfold]

That is going to be/is an excellent resource.

[Ant]

Another page added >>here<< for NGC 896 / IC1795. A little noisy these single subs... but they do the job.

Thanks to Rob and Tony for sending me some files - they are not up yet, but they will be!!!

Cheers

Ant

[NickH]

Will get mine to you soon mate, a bit snowed under with all sorts !