Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Carole on Jan 29, 2013, 21:36:22

Title: M42 HaRGB
Post by: Carole on Jan 29, 2013, 21:36:22
Wanted to add some Ha to the QHY8L RGB image I took earlier in the month.  Despite a FULL MOON I decided to grab it before Orion gets too low as who knows when we'll get another clear evening?

I think this has brought out more detail and even resolved the stars in the trapezium.  Still experimenting and exploring what can be done with Mono and OSC.

Previously taken RGB QHY8L  1 hour 40mins on ED80
and now 2 1/2 hours Ha Baader 7nm Atik383L cooled to - 10degrees on ED120 (should have used ED80)
Guided with finderguider on NEQ6
of which I did 900sec x 7, 300sec x 8 and 30sec x 6

Still getting a bit of noise (in the RGB image), should I be using even lower temperatures, or is this through not having a LP filter for the RGB, or is it just plain Bromley?

Link to larger image
http://gallery.orpington-astronomy.org.uk/albums/userpics/10047/M42_1hr_40_RGB_%2B_2_5_Ha.png

(http://gallery.orpington-astronomy.org.uk/albums/userpics/10047/normal_M42_1hr_40_RGB_%2B_2_5_Ha.png)

Title: Re: M42 HaRGB
Post by: Carole on Jan 29, 2013, 21:37:42
Similar crop of RGB only for comparison:

(http://www.caroleastronomy.webspace.virginmedia.com/_wp_generated/wp4727adb2_0f.jpg)

Title: Re: M42 HaRGB
Post by: Whitters on Jan 30, 2013, 07:03:55
Carole, that's a really nice shot. The difference the Ha makes is very obvious, the nebula has more depth to it giving a sense of 3D.
Title: Re: M42 HaRGB
Post by: Carole on Jan 30, 2013, 08:07:44
Thank you Paul.

Carole
Title: Re: M42 HaRGB
Post by: Ivor on Jan 30, 2013, 08:42:19
Great result, I like the detail you've managed to pull out. I tried this target before Chirstmas and plan to process it over the next two weeks, I'll be pleased if my efforts are as good.

Title: Re: M42 HaRGB
Post by: Jim on Jan 30, 2013, 10:58:06
Well done Carole, that is a very nice image
Title: Re: M42 HaRGB
Post by: Carole on Jan 30, 2013, 15:28:14
Thanks Ivo and Jim. 

Carole
Title: Re: M42 HaRGB
Post by: MarkS on Jan 30, 2013, 21:57:39

The extra H-alpha data has certainly made a difference.  It's looking good.

The noise in the RGB data is certainly from light pollution and not thermal noise from the CCD.  It's because this is wideband data.  A light pollution filter would certainly help but even then, light pollution would still be the limiting factor.

You should have a lot less noise in the Ha data, although with the moonlight it will still be a lot noisier than it should be.

Mark
Title: Re: M42 HaRGB
Post by: Carole on Jan 30, 2013, 22:33:59
Thanks Mark,

Yes there is no discernable noise in the Ha image, it's all the the RGB, and considering it was Bromley with no LP filter, I guess this is not really surprising.  I now have a 2"CLS filter so I will use that next time with the OSC. 

Carole