Help: need PP advice on wide field images

[Axeldude]

Hi all,

Been a while since I've last posted here, I've been out of the game for a while but I'm ready to get back into it with my newly purchased AstroTrac!

Yesterday I took a few shots from Cassiopeia (4 x 5 mins, iso 200, f4.5) and I came up with this as result attached.

Altough I think it's pretty good for a first try there's still room for improvement.

Anyone have a workflow for processing widefields?

Heres my unedited file on dropbox: https://www.dropbox.com/s/hf697krh6ljf6qz/clean%20edit.TIF?dl=0

Thanks!

Axel

[Axeldude]

Forgot to attach the image ..  

The subs were taken with an unmodified 600D with 24-105 f4l lens @ 32mm/f4.5

[andrewluck]

That's a very orange picture. Are you in the city?

Widefield is every sensitive to light pollution gradients. Can you find somewhere darker for your imaging?

Cheers

Andrew

[Axeldude]

Im near the Antwerp harbor and the orange dome is very visable, this was taken away from the dome

Might a cls filter do the trick to remove the gradient?

Cheers

Axel

Sent from my iPad using Tapatalk

[andrewluck]

Another thought occurs. Did you get the images off the camera in RAW format? I've found that if you let the camera handle conversion to jpeg then it blows the orange up.

A CLS filter would help. You'll probably need to rebalance the colour if you use one but you'll be able to use longer exposures before the sky glow overwhelms everything.

Cheers

Andrew

[ollypenrice]

The best software anti-gradient tool is DBE in Pixinsight. It works brilliantly well on widefields where you have plenty of background sky to identify for the programme. It also pulls the colours into line in an excellent caibration and sets black and white points beautifully. You can also use SCNR green to help your colour. The image above would be easily pulled into perfect shape by DBE.

Olly

[lensman57]

Hi all,

Been a while since I've last posted here, I've been out of the game for a while but I'm ready to get back into it with my newly purchased AstroTrac!

Yesterday I took a few shots from Cassiopeia (4 x 5 mins, iso 200, f4.5) and I came up with this as result attached.

Altough I think it's pretty good for a first try there's still room for improvement.

Anyone have a workflow for processing widefields?

Heres my unedited file on dropbox: https://www.dropbox.com/s/hf697krh6ljf6qz/clean%20edit.TIF?dl=0

Thanks!

Axel

Hi,

Here is a version with two passes of the ABE tool in Pixinsight. One pass to correct by division, fuction degree of 2,  and the other to correct by subtraction with default values.

I have applied background equalisation and colour calibration to the linear image and then stretched by STF parameters for simplicity. 

A.G

PS: Personally speaking I find the processing of these widefield shots quite demanding.

[wavydavy]

I use a CLS clip filter, in fact mine stays in my canon permanently. Well for me I think as you are still experimenting with your new astro trac........its a good image, I dont think the light pollution in the picture is "that bad" ive seen a lot worse, and its pretty easy to remove with a few mouse clicks. I agree with the above comments, the CLS will throw the colour balance, especially it the camera is modified, but processing will sort it. Well done on your image!

[andrewluck]

Sorry, I wasn't explicit in my earlier post. The orange I was referring to is really apparent on the tif file hence my question on the format that the images were pulled off the camera.

Cheers

Andrew

[Axeldude]

Oh my, it's been a month again since I've last visited this place, I've been so busy with work lately .. should take a bit more time off and get back into this hobby

Another thought occurs. Did you get the images off the camera in RAW format? I've found that if you let the camera handle conversion to jpeg then it blows the orange up.

A CLS filter would help. You'll probably need to rebalance the colour if you use one but you'll be able to use longer exposures before the sky glow overwhelms everything.

Cheers

Andrew

The images came straight from the camera in RAW format, stacked in DSS, played a bit and saved as a TIF file for the rest of the processing in Photoshop, I think I'm getting a CLS filter in a few weeks, sadly there haven't been a lot of cold, clear nights lately

The best software anti-gradient tool is DBE in Pixinsight. It works brilliantly well on widefields where you have plenty of background sky to identify for the programme. It also pulls the colours into line in an excellent caibration and sets black and white points beautifully. You can also use SCNR green to help your colour. The image above would be easily pulled into perfect shape by DBE.

Olly

Thanks for the tip Olly, should take a look at Pixinsight, seems like a neat little program.

Hi,

Here is a version with two passes of the ABE tool in Pixinsight. One pass to correct by division, fuction degree of 2,  and the other to correct by subtraction with default values.

I have applied background equalisation and colour calibration to the linear image and then stretched by STF parameters for simplicity. 

A.G

PS: Personally speaking I find the processing of these widefield shots quite demanding.

I noticed that widefield shots are harder to post process, lol ..

So another vote for pixinsight, might as well bite the bullet!

Thanks for checking the image out, I like how it has more detail to it! 

I use a CLS clip filter, in fact mine stays in my canon permanently. Well for me I think as you are still experimenting with your new astro trac........its a good image, I dont think the light pollution in the picture is "that bad" ive seen a lot worse, and its pretty easy to remove with a few mouse clicks. I agree with the above comments, the CLS will throw the colour balance, especially it the camera is modified, but processing will sort it. Well done on your image!

Thanks mate, well noted