HH and Tarantula widefield - 4hours in Ha

multiweb (Marc) · #1 23-12-2008, 03:27 PM

The weather's been atrocious and I’ve been grabbing bits and pieces through sucker holes for the past few months increasing the data I had on those two frames. I’m now around 4 hours exposure time on each. The noise is certainly getting better and better as I add more subs to the stack but I need a lot more to get rid of it completely to use these as a luminance channel. I shot those from home in my backyard. There’s no point doing RGB where I live so I do exclusively Ha and keep the colors for the new moon week-end when I drive away from Sydney.

About the pictures: both taken at prime focus on a 5” Celestron Newtonian, QHY8 Gain:1 Offset:60. Guided with ED80/PHD on G11 and captured with Neb2. I used the dithering in PHD. Subs were 900s. The data was acquired between November and December. Processed and stacked in CCD Stack.
I did run one pass of noiseware in PS and adjusted the core brightness down on the Tarantula.

If anyone interested the full frames are available at:
http://www.multiweb.com.au/astro/ic434_20081222_ha_f.jpg [3.3MB file]
and
http://www.multiweb.com.au/astro/ngc2070_ha_20081223_f.jpg [2.76MB file]

Thanks for looking. Comments/Tips most welcome.

dugnsuz (Doug) · #2 23-12-2008, 03:49 PM

Love both of them Marc - HH is my fave though.
It's such a Ha-friendly object n'est pas!!??
Very nice
Doug

bluescope · #3 23-12-2008, 05:23 PM

Very nice images Marc .... new moon is not far away for some colour

The QHY8 coupled with your 5" Newt gives a nice wide fov.

Paddy (Patrick) · #4 23-12-2008, 06:40 PM

Some beautiful detail in both of them Marc. I don't know anything about imaging, but I had no idea that you could capture so much with a 5" newtonian. I'm well impressed.

multiweb (Marc) · #5 23-12-2008, 07:11 PM

Quote:

Originally Posted by dugnsuz

Love both of them Marc - HH is my fave though.
It's such a Ha-friendly object n'est pas!!??
Very nice
Doug

Oui , Merci

Quote:

Originally Posted by bluescope

Very nice images Marc .... new moon is not far away for some colour

The QHY8 coupled with your 5" Newt gives a nice wide fov.

Thanks. Yes it is a nice match. Nearly as big as the ED80.

Quote:

Originally Posted by Paddy

Some beautiful detail in both of them Marc. I don't know anything about imaging, but I had no idea that you could capture so much with a 5" newtonian. I'm well impressed.

Oh you certainly don't need to spend a lot on your scope to do nice pictures. You need a good mount and a decent camera. That's all.

Garyh · #6 24-12-2008, 10:19 AM

Nicely detailed Ha shots there! Marc verry nice!

peter_4059 (Peter) · #7 24-12-2008, 10:38 AM

Both great images Marc. How do you achieve the same composition when you combine images from multiple sessions?

Ric · #8 24-12-2008, 10:46 AM

Lovely images Marc, Ha really does these areas justice.

Cheers

multiweb (Marc) · #9 24-12-2008, 11:40 AM

Quote:

Originally Posted by Ric

Lovely images Marc, Ha really does these areas justice.

Cheers

Thanks Ric. Yeah there's plenty of Ha stuff around especially the tarantula.

Quote:

Originally Posted by peter_4059

Both great images Marc. How do you achieve the same composition when you combine images from multiple sessions?

Thanks Peter. I do a rough polar alignment usually within 10' on each side of the pole then find a few alignment stars and finally sync the gemini on a bright alignment star within the area of the DSO. For the Tarantula I sync on Canopus and Betelgeuse for the HH. When I slew from the star to the DSO I'm usually spot on. The G11's great for that. Consistant. I never get exactly the same framing but it's +/- 10-20 pixels. Good enough not to have to crop too much. In CCD Stack I use CCDIS. It aligns based on star patterns so it will combine subs from each side of the meridian without a sweat.

Quote:

Originally Posted by Garyh

Nicely detailed Ha shots there! Marc verry nice!

Thanks you very much Gary - glad you like them.

mick pinner · #10 24-12-2008, 11:46 AM

they are both very fine images, well done.

jase (Jason) · #11 24-12-2008, 12:33 PM

Really nice work Marc. The additional data is allowing you to work it harder. Tarantula is quite a visual treat. Would be good to see these target in color. Well done.

multiweb (Marc) · #12 24-12-2008, 04:59 PM

Quote:

Originally Posted by jase

Really nice work Marc. The additional data is allowing you to work it harder. Tarantula is quite a visual treat. Would be good to see these target in color. Well done.

Thanks Jase. Much appreciated. That's the beauty with Ha. You can always add to it and it looks better and better. I hear you with the color but it's a whole new ball game for me to integrate properly and you need good data to do so. Imaging RGB from home is not an option. Acquiring color on new moon week-ends... well, the weather's been a bit like that

lately. It's going to take longer.

marc4darkskies (Marcus) · #13 24-12-2008, 05:11 PM

Hey - nice job Marc!!

Both images are a visual treat, well done. Love those Ha only images!

Have you tried Neat Image for noise reduction (it has a PS plugin as well)?

Cheers, Marcus

multiweb (Marc) · #14 24-12-2008, 05:18 PM

Quote:

Originally Posted by marc4darkskies

Hey - nice job Marc!!

Both images are a visual treat, well done. Love those Ha only images!

Have you tried Neat Image for noise reduction (it has a PS plugin as well)?

Cheers, Marcus

Thanks Marcus - Cool! I checked the website. Apparently it even works as a smart filter in CS4. That's interesting. Non destructive layered noise reduction. Thanks heaps for the tip.

dcalleja · #15 24-12-2008, 05:42 PM

Marc
Really nice, great detail in the wavvy structures to the right of the horse (totally missing in my version). The QHY seems to be a really good cam.

It just goes to show how much detail you can get with decent exposure times (I really must follow your lead on this) even from a suburban backyard.

Hagar (Doug) · #16 24-12-2008, 05:42 PM

Very nice images Marc. Takes me back to film with the grey scale. Somewhere I don't want to return to. The detail you have captured is wonderful. You certainly get the best out of the QHY8.

multiweb (Marc) · #17 24-12-2008, 06:07 PM

Quote:

Originally Posted by Hagar

Very nice images Marc. Takes me back to film with the grey scale. Somewhere I don't want to return to. The detail you have captured is wonderful. You certainly get the best out of the QHY8.

Thanks for the kind comments Doug. Love your work too.

Quote:

Originally Posted by dcalleja

Marc
Really nice, great detail in the wavvy structures to the right of the horse (totally missing in my version). The QHY seems to be a really good cam.

It just goes to show how much detail you can get with decent exposure times (I really must follow your lead on this) even from a suburban backyard.

Thanks Dan. Yes Ha and narrow band in general can be done from light polluted backyards. Just stick at it and collect data one sub at a time. Each new sub is "money in the bank" so it's a very rewarding feeling.

The QHY8 has definitely a lot of potential once you've worked out all the drivers issues and hurdles it performs quite well on a budget. It's not a camera for the "faint hearted" though.

gregbradley · #18 24-12-2008, 09:10 PM

You're off to a flying start! Well done on your persistence and boy don't we need it these days in Oz with the weather being imaging unfriendly!

A couple of minor suggestions:

1. As you mention you would've liked more exposure time (don't we all!) and I take it you used 2x2 binning with your QHY8 and there is some background noise. You could download a free trial of Noise Ninja and run that and it will help. Or perhaps even moving the black point a tad more in levels or even using the blur tool and smoothing out the heavier areas of noise.

If you don't then when you do your mix of the Ha with the RGB colour you'll get that noise showing up as red and it will be more intrusive at the point.

Then do selective sharpening on the horse itself to sharpen only that area up and nothing else.

2. The Tarantula core is slightly overblown. You could lasso it and use curves/levels or shadows/highlights to get the detail back in the blown areas and then do 1 above to selectively sharpen the Tarantula neb area itself.

Greg.

multiweb (Marc) · #19 27-12-2008, 09:06 AM

Quote:

Originally Posted by gregbradley

You're off to a flying start! Well done on your persistence and boy don't we need it these days in Oz with the weather being imaging unfriendly!

Thanks Greg. Yeah the weather is a bit of hit and miss right now for everybody especially in Sydney.

Quote:

Originally Posted by gregbradley

A couple of minor suggestions:

1. As you mention you would've liked more exposure time (don't we all!) and I take it you used 2x2 binning with your QHY8 and there is some background noise. You could download a free trial of Noise Ninja and run that and it will help. Or perhaps even moving the black point a tad more in levels or even using the blur tool and smoothing out the heavier areas of noise.

If you don't then when you do your mix of the Ha with the RGB colour you'll get that noise showing up as red and it will be more intrusive at the point.

Then do selective sharpening on the horse itself to sharpen only that area up and nothing else.

That was binned 1x1. I loose a bit of resolution when debayering but it's still better than binning 2x2. I just collect the red channel for Ha. I have a slight signal in green but I don't use it (the core in the tarantula) and a lot of noise in the blue. I downloaded Noise Ninja. Thanks for the link and I'm playing with it now. Pretty cool plugin. Yes I did get red noise when playing with the tarantula frame as lum/luminosity layer in PS.

Quote:

Originally Posted by gregbradley

2. The Tarantula core is slightly overblown. You could lasso it and use curves/levels or shadows/highlights to get the detail back in the blown areas and then do 1 above to selectively sharpen the Tarantula neb area itself.

Greg.

I used the Shadow/Highlight tool but processed the picture as a whole. I like to keep the cores fairly bright (same for M42). I find that dimming them too much in respect to the rest of the pictures makes the frame look "flat". I'm not really a fan of fully resolved core for widefields. I think a crop of the core with a longer FL looks nicer rather than trying to integrate it to a larger frame. The distribution of the light from center to the edges looks more natural. But that's a personal preference. Like colors

I do most of the sharpening in CCD Stack. Now I have noise Ninja and Neat Image I'll be able to post process the sharpening a bit harder without having to worry so much about bringing the noise level up which was the limitting factor to date.