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11/30/-1
    
Tuesday, November 24th, 2009
Tonight was clear enough for experimentation. The fog was high all night and ultimately rolled in making me turn in hours before I would have liked.

I had the gear out acclimating for a while and by the time I got out to it everything was very wet. Not a good sign.

Even still, the sky was essentially clear - that is, I could see stars, so I went ahead with the experiments.

I performed some Live View focusing tests on Polaris (1.96 Magnitude) with and without the 12nm Ha filter. The screenshots are in the gallery below. The bottom line is that Polaris is just visible without the filter and barely visible with the filter. In fact, with the filter, I needed to know where it was in the frame in order to get the magnified view of it.

More Hydrogen Alpha Imaging
The primary target tonight was the California Nebula with the Ha filter via the ZenithStar 66. 20 minute sub exposures and at least an hour of integration time (but hopefully 3). So the goal was met, but it would have been nice to get the 3 hours instead I only got 1.
 
The California Nebula NGC 1499 Image in H-alpha
I've been wanting to shoot this since I got the Ha filter, but we haven't had a clear night. Tonight was only good for a short time and I only got an hour on it. Even still, it turned out better then I expected. I was disappointed when I saw the frame come through with 3 satellites in it. I knew that I wouldn't get enough frames to get rid of the trails.

I was stunned at how much signal was acquired for only 1 hour. It's more and better signal then what was achieved in an hour with the MegRez 90 last year in the desert. Image here: Cali Shot 08.


Scope: William Optics ZenithStar 66 SD @ f/4.7 w/WO 0.8x Flat II Reducer
Mount: Orion Sirius EQ-G with GoTo
Guiding:  Meade DSI Pro and PHD Guiding
Guide Scope: Vixen R200SS 200mm
Camera: Canon EOS 1000D (modified) w/Astronomik 12nm Ha Clip In Filter
Special Settings: None
ISO: 1600
Exposure: 1 hour - (3 x 1200s)
Processing Software: Acquired in Nebulosity with Extreme dithering, Stacked in Deep Sky Stacker (Kappa-Sigma Median Clipping for all frames), Levels, Curves, Astronomy Tools, Gradient XTerminator and Noise Ninja in Photoshop
Support Files: 0 flats, 50 bias, 3 darks
See Gallery below for image


Image Gallery For This Session
01 California Nebula Ha 1h 02 Screen Neb 3 second
03 Screen Live View Polaris Custom WB 04 Screen Polaris Daylight WB
05 Screen Polaris Daylight WB Zoom 06 Polaris Live View Ha
07 Screen Polaris Live View Ha Zoon 08 Screen Polaris Live View Ha Zoom Focused
   

01-California-Nebula-Ha-1h.jpg
Click picture above for larger version
If the picture seems too bright or too dark, try adjusting the brightness below.
Brightness:
|
  



Comments:
On 11/28/09 at 01:22pm Jeff W. wrote:
Very nice image Neil. 3 x 1200, 20 minute exposures, wish my gear would guide that nice. I like the red, not the really blown out red a lot of people who shoot ha use but a nice contrast to the monochrome you see a lot of in ha images. You got a lot of image for 1 hour, from everything ive read using a narrow band filter like that means you really have to increase exposure time.

Jeff W.

On 11/26/09 at 12:33pm Neil Heacock wrote:
Yup. Exactly. It's a very nice method of colorizing a grayscale image. Maybe not 100% accurate, but Noel did a fine job isolating the stars and the nebulosity. I still think his toolkit is the best $20 I've spent in astronomy.

-Neil

On 11/26/09 at 09:11am Greg wrote:
Thanks. So I guess this action effectively recognizes stars (small bright dots), leaves them alone and suppresses blue and green elsewhere. It seems to work quite well except for a couple of places where halos around stars are red.


On 11/25/09 at 09:22pm Neil Heacock wrote:
Thanks Barry. I'm well pleased with the shot.

Greg, I'm still looking into pixel rejection stacking options to see if I can get rid of the satellites. Normally they go away with the median sigma clip stacking, but I also usually have more then 3 frames!

Regarding the processing. the picture was captured 99% in the red channel, Converted to grayscale and processed, then re-colorized using Noel Carboni's "B&W -> Ha False Color Black Space" action and finally tweaked a bit more.

-Neil

On 11/25/09 at 09:12pm Greg wrote:
That looks great, Neil - too bad about the satellites.

Since the stars are white you must have either combined the H-a with other image data or created a mask for the stars and forced them to white, right?


On 11/25/09 at 10:01am Barry wrote:
Hey Buddy, what did you want....candy & flowers...dinner and a movie? He hee hee. It's a great shot!

On 11/25/09 at 04:43am Barry wrote:
Terrific



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