Ha Carina Nebula

[Mickoid (Michael)]

Despite this object heading toward Melbourne's light dome from a Bortle 6 location, a 7nm Optolong Ha filter had no problems pulling out the nebulosity surrounding Eta Carina last night. Just a test to see how it would perform. I had to push the subs out to 5 mins to achieve enough signal to show some detail. Mounted on an old HEQ5 non GOTO, I shot 8 x 300 second unguided subs with a vintage Pentax 135mm prime lens set at f5.6, using a Modded Canon 550d for a total of 40 mins exposure at 1600iso. Some darks but no flats, this image is a process of the red channel only. It's rather noisy but the filter passed the test.

[Anth10 (Anthony M)]

Onya Mick!

New toy hey? Good to see plenty of Ha coming through mate - nice widefield. I'm sure you will make this work in many applications and beat that every growing light pollution....
Anthony

[Mickoid (Michael)]

Thanks Anthony, appreciate the encouragement. It will also enable me to grab some Ha when the moon is in the sky and add it in the form of luminance or red enhancement later on to RGB data of the same object.

[xelasnave]

Michael you must be happy with your mount ....I do not think mine would do as well under auto guiding..well done.

How do you process?

You probably know I am a big Star tools fan and I will bet it would make that noise disappear and do wonders for your image in that area.

However let's look at the positives and I say you have done very well...

Alex

[Mickoid (Michael)]

Thanks Alex, I stack in DSS and combine the processed results of DSS and StarTools in Photoshop. Alex, I don't know any program that would remove noise from a stack of 8 subs at 1600iso without also removing the resolution of the image. StarTools does a great job of noise reduction but unfortunately it's just a byproduct of this camera using it at high ISO values with very little signal.

[AstroViking (Steve)]

Looks good to me, Michael.

Would you benefit from more subs of shorter duration to help chop the noise out? Rather than having 8 subs, how would 40 of 1 minute each turn out?

Cheers,
V

[multiweb (Marc)]

Very good Michael. That lens is a keeper.
Did you have to stop it down much?

[Mickoid (Michael)]

Originally Posted by AstroViking

Looks good to me, Michael.

Would you benefit from more subs of shorter duration to help chop the noise out? Rather than having 8 subs, how would 40 of 1 minute each turn out?

Cheers,
V

Probably would have Steve, I guess I just wanted to see something appear on the camera screen after one exposure to see some structure in the nebula. A one minute sub would hardly have shown anything until, like you said, I stacked all 40 of them in post processing. At least I know that is worth trying.

Originally Posted by multiweb

Very good Michael. That lens is a keeper.
Did you have to stop it down much?

Thanks Marc, it's a f3.5 but I stopped it down to f5.6, it's even better at f8.

I actually found some RGB data of the same region taken with the same lens last year. The problem was it was taken at a different time of the year and the framing was nearly 90 degrees from the Ha framing I did the other night. Consequently, when I replaced it with the RGB's red channel, the stars didn't quite align due to lens distortions and image scale. The second one is the Ha used as a luminance layer.