Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Carole on Jul 05, 2012, 11:01:33

Title: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 05, 2012, 11:01:33
I tried an experiment in adding the Ha image from my Atik into the DSLR image to see how this would work with a long term view to getting an HA filter for the DSLR.

This is the Atik CCD image in Ha taken back in March 600 x 9

(http://www.caroleastronomy.webspace.virginmedia.com/_wp_generated/wp89b9d441_0f.jpg)

This is a crop of the DSLR image done in November 300 x 49 mins (cropped to match the CCD FOV)

(http://www.caroleastronomy.webspace.virginmedia.com/_wp_generated/wp25d22630_0f.jpg)

aligned in Maxim and then the Ha added to the red channel of the DSLR image in Photoshop CS3

(http://www.caroleastronomy.webspace.virginmedia.com/_wp_generated/wp2babb209_0f.jpg)

Needs a bit of noise reduction, but as an experiment at least I can get it to work.
Having a bit of a problem with bright blue when I add data to the red channel.

In view of the reduced imaging capacity of an HA filter with a DSLR, would I be better getting a 35nm filter for the DSLR?

Carole



Title: Re: Ha added to DSLR image of Horsehead
Post by: Rocket Pooch on Jul 05, 2012, 11:21:48
Thats actually quite good.
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 05, 2012, 11:22:39
Thank you Chris that is reassuring.

Carole
Title: Re: Ha added to DSLR image of Horsehead
Post by: Rocket Pooch on Jul 05, 2012, 11:26:03
If you can get the colour balance where you want it in Photoshop with Ha as Red, then try applying the Ha again as luminance, you can then apply a Median filter to the RGB stack and you will see ther noise drop out, but remember to add a Saturation layer between RGB and Ha and set the saturation at 25% or more, or you will not see many colours.


This will then be an RGBHa
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 05, 2012, 11:31:06
Oops, a bit too technical for me as yet Chris, but I'll work on it slowly. It has taken me a while to work how how to align in Maxim and add the Ha channel which is why it is so delayed.

But as a starter, where do I put the luminance channel.  Do I add an extra channel, if so I already tried that with disasterous results !!!!  :cheesy:

Obviously still a lot to learn.

Thanks for your anticipated help.

Carole
Title: Re: Ha added to DSLR image of Horsehead
Post by: RobertM on Jul 05, 2012, 12:56:35
I'd also add 25% of the Ha signal to the green to represent Hb and give you a better colour balance.

Robert
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 05, 2012, 13:37:36
How do I select 25% Robert?

Sorry this is all a new ball game for me.

Carokle
Title: Re: Ha added to DSLR image of Horsehead
Post by: RobertM on Jul 05, 2012, 20:15:31
How did you add 100% to the red channel ?  All you do is the came but scale the amount back.  It's been a while since I did any PS but it might be lightness in the layer you add to the green channel.

Let me know if you're still having trouble and I'll load PS or cheat and have a look on the web ;)

Robert
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 05, 2012, 23:18:03
All I did was copy and paste the Ha image into the red channel, no options to choose a percentage. 

Carole
Title: Re: Ha added to DSLR image of Horsehead
Post by: Mac on Jul 06, 2012, 06:44:49
Have a read, might give you some ideas.

http://forum.orpington-astronomy.org.uk/index.php?PHPSESSID=88e3d8594c21b45b7255ec1e04e1dd41&topic=7739.0 (http://forum.orpington-astronomy.org.uk/index.php?PHPSESSID=88e3d8594c21b45b7255ec1e04e1dd41&topic=7739.0)

Mac
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 06, 2012, 09:12:09
Thanks Mac, I had forgotten about that thread.  This uses a different method to the one I was following i.e. using layers whereas the one I was following pasted the different channels into the channel palette.

Added to my useful favourites and will peruse.

Carole
Title: Re: Ha added to DSLR image of Horsehead
Post by: RobertM on Jul 06, 2012, 18:49:55
Carole,

The layers method is very powerful as you can can even blend the best bits for instance an over sharpened and noisy to one that's less less sharp and more smooth - the best of both worlds so to speak.

Robert
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 07, 2012, 00:26:52
Thanks Mac and Robert.  I started to take a look at that today but other things took over.  will have a serious look in the next few days.  As you may have noticed I have been doing a lot of processing and experimenting of late.

Carole
Title: Re: Ha added to DSLR image of Horsehead
Post by: Mac on Jul 08, 2012, 19:34:48
QuoteAs you may have noticed I have been doing a lot of processing and experimenting of late.

Why? have the skies be cloudy or something?  :cheesy:

Mac
Title: Re: Ha added to DSLR image of Horsehead
Post by: Carole on Jul 08, 2012, 21:50:05
 :lol: