Canon T3 - H-alphaRGB - First try

[jsmoraes]

Full Moon, high humidity with a faint fog.

Well, let me try to explain what was done.

1. First, 15 subs RGB, ISO 800 and filter Skyglow with 240 seconds.

Image of file RAW CR2 - photo 1

Image from stacking in DSS - photo 2

note: Stack in DSS disappeared with original colors informations.

Image of HDR process in Photoshop CS3 - photo 3

2. Then, 7 subs filter H-alpha 12 nm, sensor RGB Canon T3, ISO 1600 with 240 seconds.

Image of file RAW CR2 - photo 4

Image from stacking in DSS - photo 5

3. I did two different process with H-alpha in HDR of Photoshop CS3 to be used in global process.

Image of H-alpha with HDR wide field - photo 6

Image of H-alpha with HDR central field - photo 7

4. Copied the Red channel of light image RGB and done superposition of images H-alpha:

layer 2 - image Halfa wide field - 40 % opacity
layer 1 - image Halfa center field - 50% opacity
background - light image RGB - 100% opacity

5. Applied only curves, bright, contrast and to reduce of presence of stars minimum filter.

Final image - photo 8

note: It was not applied any other filter or process. My intention was to see the performance of H-alpha filter with unmodified Canon.

More tests wil be done.

[alistairsam]

hi Jorge,

Nice effort but I think you'll get far better results if you just replace the IR glass with clear glass. That will let a lot more of Ha data through.

For the Ha, did you discard the G and B channels? they'll almost have no data so just use the R.

Cheers
Alistair

[jsmoraes]

Thank you alistairsam.

Not if you live in Brazil. :rolleyes:


Yes, I used only the red channel, with two differents process: wide and center.

See, alistairsam. I didn't try, yet, to process the RGB image as normally I do. Only to compare them.
But You can see that the image from stacking process hasn't many color informations. The original CR2 photos have few red information, too.

It seems that the H-alfa helped to fill with some real red information. It is not an artificial manipulation in Photoshop.

As I told in other post, any help ... is a help ;)

I don't dream with good color photos from Canons. But I would like more faint nebulas informations without corruption by light pollution. Or artificial colorization with graphic process.

I can not buy a good mono camera. Price in dollar plus 120 % in dollar for tax in my country. And with 2.5 in cambio... out of reality. At least to me.

My photos never will show the quality of those I see here. But I want more informations from and about the objects that I shot. :thumbsup:

[cometcatcher]

Interesting test Jorge. I found the Ha sensitivity of my unmodified Pentax to be extremely poor even with a fairly wideband (30nm) Ha filter. Ended up getting an old full spectrum modified Nikon D70s that responds much better to Ha. That filter in the camera really has to go to get decent Ha shots.

[jsmoraes]

Thank you, kevin,

Theoretical response of original filter and my others. 25% of transmission in H-alfa region.

If you want a photo with visual impact ... it is poor. But to obtain information about the object, with DSLR that work with ISO, you can some result with it and total time of exposure.

I think the major problem is that you haven't 100% of pixel to catch the information as mono camera has. But there is improvement when the capture is HalfaRGB.

Mask and HDR can enhance this improvement. This will be the goal of my tests. I never did process with narrowband filters. I am just trying and learning about this task.

Nevertheless, the correct solution is:to buy a good mono camera, a good Halfa filter and go to a site with good dark-clear sky. Easy, no ? :rofl:

[jsmoraes]

And other process where the Halfa information was added in Tiff 32 bits. The first, above, it was done in Tiff 16 bits.

Some process in Photoshop CS3 was used to enhance details. But was not necessary to use any noise filter.

GSO 305 mm - HaRGB - Canon T3 - RGB: ISO 800, skyglow filter 15 x 240 sec - Ha: ISO 1600 - 7 x 240 sec

note: I lost a little of the nebula

[jsmoraes]

And now, the process without help from Halfa filter. I used similar method to process, enhance with HDR the red channel and superpositon. But from same file.

This photo was processed in Photoshop CS3 to enhance details, and it needed noise filters. Perhaps because of these filters, some details are less sharp.

Note: the first photo, more red, wasn't processed. Only curve and level to adjust de black in background was applied.

As the originals CR2 didn't come with much color informations, these tests aren't conclusive. But, it seems that with Halfa I don't need intense adjustment of curves, and inherent noises by it. And it seems to be a little clipped, too. If confirmed, the Halfa filter is positive.

As soon the sky is ok, I will continue with tests, and with another body. A faint nebula, for example, will be a good object.

[jsmoraes]

And final process in Photoshop CS3. Two version. I can not decide wich is more nice ! :question:

I like of the color with the first. And I love the details and nebula with the second !

http://www.astrobin.com/96360/

[rustigsmed]

nice work Jorge, its something I will probably start doing soon too when there is some moon out.

cheers

Russ

[cometcatcher]

That would be the ideal, but a full spectrum DSLR can still take excellent Ha pics even in light pollution or bright moonlight. Ha even sees through smog to some extent. It's a great way to image nebula when the odds are against us!

[jsmoraes]

thank you, rust and comet for coments

As I said, I hope to obtain more red information free from interference of light pollution, and with less work in curves.

I know it will not act as a perfect Ha filter. But if it enhance the quality of information... it will be doing what I need.

About Canons, I didn't believe in "APOD" photos with them. See the stars, they haven't the same shape and sharp appearance as those with a good astronomic camera.
But, for who intends to register the object... they will work well. I have some photos of star cluster with better resolution than many others photos that I saw in Internet. For me, some ones are reference to these objects. At least, up to now, while nobody capture them with a better camera.

But, as the photos in Internet, they aren't beautiful ! They are images of content and not of visual impact.

http://jsmastronomy.30143.n7.nabble.com/NGC-306-td91.html
http://jsmastronomy.30143.n7.nabble.com/NGC-2048-td100.html