Monkey head more data.

[tilbrook@rbe.ne]

Hi,

Iv'e added more data to monkey head nebula image.

Originally I had 72 minutes now 128 minutes, it certainly a good demonstration of the value of more data!

I have supplied both images, the first with more data and the original, cropping is different due to stacking issues.
http://www.iceinspace.com.au/forum/attachment_browse.php?a=128213
Apart from the satellite that zipped through one of the frames, Grrrr!
It looks smoother and slightly more detail.
8" f/4 astrograph, orion (http://www.astronomyforum.net/wiki/Orion) mini guider, HEQ Pro 5 mount.

Unmodded canon 1100D baader coma corrector.

8 minute subs at iso 800, total 128 minutes, darks flats and bias frames applied.
Median stack in DSS (http://www.astronomyforum.net/wiki/DSS), processed in PS (http://www.astronomyforum.net/wiki/PS) 7.

Cheers,

Justin.

[swannies1983]

Another top effort. Love the red. Star colours are great as per usual. How do you go about doing it?

Perhaps take the sub out that contains the satellite? Also, there's a significant gradient not fixed by flats. Do you have GradientXTerminator? Or perhaps follow the directions as per this (http://www.flemingastrophotography.com/gradients.html)?

[tilbrook@rbe.ne]

Thanks Dan!

In PS7, I usually convert to 8 bits, have to in PS7 to get full functions.

As follows.
Adjustments-levels miiddle input to 1.10 to 1.25 left input 3 to 5 if needed.
Adjustments-hue and saturation about 25%
Select-colour range- select stars-adjustments-hue and saturation 25%
Select inverse-adjustments-brightness and contrast, contrast to 10%.
Deselect.
Filter-Noise-1 pixel.
Filter-gausian blur 1.5 pixels.
Adjustments-selective colours-red 30% lesscyan. Magneta 30% less cyan.
I use selective colours quite a lot on all colours in the image. This is where I get most of the reds in my images, sometimes enhanced with a bit of adjustments-colour balance.
Of course this is not all the processes, as you know, but this seems to keep the star colours and enhance what red I have in the image and I may repeat this process several times.

I can't use gradientX in PS7, need to upgrade.
This is the way I deal with gradient.http://www.ccdastro.pwp.blueyonder.co.uk/gradient_removal.htm
Not ideal but it helps.
I forgot to use it for this image, here's another with the process applied.

Cheers,

Justin.

[Ross G]

A great photo Justin.

Again, I love your colours.

Ross.

[Larryp]

Looks superb, Justin!

[tilbrook@rbe.ne]

Thanks Ross!



Thanks Laurie!

Cheers,

Justin.

[Jbunky86]

I haven't seen this one before.

Good stuff Justin

Cheers jas

[tilbrook@rbe.ne]

Thanks Jason!

So much out there to image.

Cheers,

Justin.

[alistairsam]

Hi Justin,

You are getting some nice results but this one I think needs more data and less blur as it doesn't show much structure, just my opinion and I'm no expert.
Are you able to retain the 12 bit format while editing? I know 4 bits aren't too much but it could enhance transitions in subtle areas.
for eg, 12bit to 16bit does have quite a difference in the number of shades of gray.
PS CS5 supports 16 bit, so I presume would support 12bit native.
also, i'd suggest against using gaussian blur and to instead use dithering and darks to remove noise. the blur would remove a fair bit of contrast in areas with sharp transitions. dithering and darks are very effective with noise reduction.

this was an image i found with 5x20min subs with a cooled dslr so not a straight comparison, but i just wanted to highlight the dark areas that make details stand out if you know what I mean.
http://www.centralds.net/cam/?p=2269#!lightbox[auto_group1]/0/
Look forward to more.
Cheers
Alistair

[tilbrook@rbe.ne]

Hi Alistair,

Thanks for your input.

I'm running PS7 which is quite old, it will only allow me to have full control of the image in 8 bits and partial control in 16 bits. So most of my processing has to be done in 8.

Your right about more data, but this DSO never gets very high in the sky and was at a maximum height of 25 degrees when imaged. So I'm not going to acheive the detail that someone in the northern hemishpere.
I'm using darks, flats and bias frames, but until I have the camera cooled noise is going to be a problem in warm weather.
I will try dithering though.

I have done another repro here.

I used a little more black in reds and magneta in selective colours, also 15% more contrast on the nebulosity.

It has helped a bit.

Cheers,

Justin.

[atalas]

Nice work Justin!

[tilbrook@rbe.ne]

Thanks Louie!

Cheers,

Justin.