M83 Test

[Rezn8]

Hi All...

Meade 115mm APO + flattener, EOS60Da, CGEM, PHD, BackyardEOS, lousy editing in PS

shot from city balcony over last two nights

66 x 5min subs @ 400ISO 300sec

31 x Darks

Cropped

Link to full image if anyone wants to try at editing.

https://dl.dropbox.com/u/50035099/M83%20Edit%201.tif

[billhinge]

Hi

Done in pixinsight, mainly just histogram and curves with a range mask and the dark structure enhance script (perhaps may look too red on some monitors?)

[Cloudwatcher]

A quick lunch time tweak in Photoshop.

[Rezn8]

Thanks guys, shows me what to work towards.

[astrosathya]

One of the images is too red and grainy, while the other looks like the optics fogged up. Is it my PC showing these effects? Either case the background sky is too black..

[Cloudwatcher]

Did a bit more work on your image using the Dodge and Burn tools in Photoshop to enhance the detail in the galaxy also adding Photo Filters to saturate. The star background still needs attention but I think the main subject is looking better.......purely subjective off course.....

[lensman57]

Hi All...

Meade 115mm APO + flattener, EOS60Da, CGEM, PHD, BackyardEOS, lousy editing in PS

shot from city balcony over last two nights

66 x 5min subs @ 400ISO 300sec

31 x Darks

Cropped

Link to full image if anyone wants to try at editing.

https://dl.dropbox.c.../M83 Edit 1.tif

Hi,

I am a novice just trying to learn how to start doing some DSO imaging from a light polluted back garden, so I hope you don't mind my having a go at your capture. I did this in CS2 as an exercise for imaging M42 with a Canon 1000d and an SW100 ed. I used your original file to create a mask and stretch the final image. There is not much I could do with the core and some of the delicate detail in the arms as the core is bleached out but as a whole I am happy with it and I hope that you are too. Many thanks for posting a great image.

regards,

A.G

[Rezn8]

Wow, thanks for all the input guys.

[Jannis]

Did a bit more work on your image using the Dodge and Burn tools in Photoshop to enhance the detail in the galaxy also adding Photo Filters to saturate. The star background still needs attention but I think the main subject is looking better.......purely subjective off course.....

I've seen how you correct color balance and make almost any pic look much better in no time like it's a childs play, and i guess it probably is too if i only knew how you did it so well.

If you would be able to record a video of how you do it in photoshop i'd (and probably many others too) would be extremly happy.

I've seen a few tutorials on it, but still haven't really been able to do it very well...

[ollypenrice]

One glance at the image tells us that nothing useful can be done with it, not because it is necessarily a bad image but because most of it has been thrown away and simply isn't there to be worked on. Look at the histogram in Levels.

The image is massively black clipped. The histogram peak which we see jammed over the to the left should have the mirror image of itself visible on the left as well. Half the useful data you captured is in that discarded section and is lost. A healthy histogram should look like this;

*

Here the entire peak is visible with a safety margin of faint data to the left as well. This means the image has retained and incorporated all the useful data captured. It is absolutely vital never to clip out any of the main peak because that is your image.

Any attempt to lighten the background sky or pull out fainter signal on the clipped image, using whatever programmes you like, will be pure invention because the data simply isn't there. I'd suggest you go back and restretch the image taking care not to black clip it. If you are fighting LP black clipping may be temptiong but it is not the way. DBE in Pixinsight will be your best bet.

Olly

Edit; Note that on galaxy images the left hand side of the peak does usually rise very steeply because there is either background sky or bright galaxy and not that much in between. On an extended bright nebula the peak will rise more smoothly and gently since there is a lot of nebulosity just a little brighter than the background.

[ollypenrice]

PS, What I realize I should have done was show the effect of black clipping on the Leo Triplet image. This is how it would look;

Jet black sky and no faint signal around the galaxies. Absolutely nothing can now be done to recover the lost details.

Olly

[Rezn8]

Thanks Olly, will give it a go.