First attempt at M57 (ring nebula)

[OzDave]

Here's a scaled down version of my first attempt at M57.

It was taken using IR Cut + LP filters, ISO 400, 2 minute subs, flats, flat darks, and darks. The shots were auto-guided with PHD.

Framing wasn't particularly good, but I went with it anyway. I think the central star is just visible.

If I wanted this object to be larger, presumably I'd need a longer focal length to get the magnification, and then probably a larger aperture to compensate for the longer focal length (or longer subs). Does that sound right?

I've seen some M57 images with red hues as well as blue/green. Am I doing something wrong that I only get Blue/Green? Do I need different filters, more subs, longer subs, modified Canon EOS, proper Astro CCD instead of DSLR, something else? Or does this look normal?

Dave

[gary1968]

Nice image mate. I aint tried that object yet. As for the other colours you mention, if you remove the IR cut filter you should let the red light through improving the red channel, IIRC.

Gary

[the rev]

Nice clear image, wih good round stars. As said above remove the filter to let red in.

Kate

[OzDave]

Hmm...well...removing the IR Cut filter would be easy, but I'm pretty sure the Light Pollution filter covers most of the IR Cut filter's spectrum, but I could be wrong. Not really sure why I use both filters, but since I have them...

And then, my DSLR is unmodded, so has its own IR cut filter.

Am I fighting a losing battle with Red here? I'm thinking simply removing the IR Cut won't be enough as I've tried this target before with no filters and got similar (but unpresentable) results in the colour.

Any other ideas?

[davew]

Hi Dave,

From the details supplied, that's just how I would expect M57 to look. It's a very small object and yes, you will need to get closer in to see any red at the edges and then only just.

To give yourself a better chance I would make sure it's centered and up the ISO to 800. Then have another go. Try 2 mins again ( single shot ) and have a look. Then 3 mins then 4. Which ever looks the best have another run at it.

I'd also take the IR filter out. Why have a lump of useless glass in the system if the LP filter has it

It's good image. Back to work

Dave.

[gary1968]

my 1000d is unmodded and I get a fair bit of red in my images, I have imaged the HH and the Rosette, both are mainly red. For these I used a CLS clip. I have just bought a SW 2" LP filter so will be giving that a try instead of the CLS Clip next time out, wich will be Autumn.

Give it a go without the IR cut filter and as mentioned above try some longer subs, if you have a barlow or image mate you could try them to get in a bit closer.

On the whole its a great start and like most things in this hobby it takes perseverance to get it to a stage where you'r happy with it.

HTH,

Gary