Tuesday, August 10, 2010

M8 Lagoon - So-So Attempt

I need more light for this object, but this is a step in the right direction. If I increase the exposures to 6 minutes and maybe aim to get 15+ frames to assist with noise reducion, I should be in good shape. My guiding is looking decent though. It's still a tad noisy, even at ISO400.

Image details:

* Imaging Scope: Astrotelescopes 80mm ED Refractor
* Imaging Camera: Nikon D40
* Guiding Scope: William Optics 66mm Petzval Refractor
* Guiding Camera: Meade DSI-C
* Exposures: 6 * 4 minute lights, 4 * 2 minute darks
* ISO 400
* Aligned and Stacked in Deep Sky Stacker
* Post-Processing in GIMP (contrast, saturation and unsharp mask)
* Noise reduction in Neat Image


Polaris B said...

Yes! Guiding on 4' subs! Congrats! This looks good, Phil!

Phil said...

Thanks,mate. I went out on Friday night with the hope of going for longer exposures but there were too many high level clouds to do anything useful. I did see some nice meteors though!

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Tobin said...

Could you describe what you mean by this?

Exposures: 6 * 4 minute lights, 4 * 2 minute darks

I think I get the general jist of it, obviously to avoid underexposures or blowing out the highlights your exposing for different periods of time and then stacking. At least I am assuming that is what you mean.

Paula Ilha said...

Hi Phil,

Very nice blog!
I'll follow it.

Best regards.

Phil said...

Tobin - I *attempt* to explain this in another blog post, but there are probably other sites that do it better than I.


Anyway, at a high level, the light frames are images you take to gather the actual light photons. You take as many as you can so that the stacking software can reduce the overall noise ratio. The dark frames are used to help point out and take away bad pixels and camera noise.

Ideally, you want tog et as many lights as possible tor educe as much overall noise as possible when stacking. Then, you want to take as many darks as possible which are the same exposure times as the light images you take. (With my M8 picture I was rushed, so only took darks which were half the time length of my lights).

You also need to take flats and bias frames. These are also explained at the link above.

Let me know if you have any other questions!


Phil said...

Hello Paula,

Thanks for visiting and following! I'll do the same with your blog and will add a link!


Phil said...

Hi Megaan,

Will do!


Mike Sherif said...

nice one...thanks'