Trifid and Lagoon

[Asterix2020]

Well, the clouds ended my session earlier than planned, so I only got 8 subs, was going for 20.

Full res: http://www.astrobin.com/full/93447/0/

Thanks for looking.

[rustigsmed]

very nice - especially for only 40mins, you're pumping out the images at the moment Paul, nice work.

[Asterix2020]

Thanks Russell. I was really annoyed to see the cloud roll in and ruin some of the shots.

[cometcatcher]

Really nice for 40 minutes.

I was shooting the same thing last night but only got 2 subs before the clouds rolled in. :(

[RickS]

Nice work, Paul, but just a bit too saturated for my taste.

Cheers,
Rick.

[irwjager]

That is very, very impressive for a mere 40 minutes of exposure.
Your colouring is informative are very much spot-on. Compared to, for example, Bert's recent M8 (http://d1355990.i49.quadrahosting.com.au/2014_03/259483.jpg) (and many other M8s on this forum) you managed to keep color constant and comparable regardless of where a pixel sits in the dynamic range (e.g. you took your luminance processing out of the equation where possible). Consequently, you have extensive coloured detail in, for example, M8's core, which gives the observer clues about its chemical make up and/or other processes going on in that area. In addition, your stars all are coloured in a consistent manner and allow for objective comparison of their temperatures.

It's 2014 and people think it's still okay to stretch their colour information along with their luminance information. Just because you stretched your data in a certain way (or picked a particular exposure length) doesn't mean that things magically change colour out there in space just for you! Colour should be rendered as it truly is; a ratio of photon emissions as measured at particular wavelength intervals. This ratio is a constant - it does not vary depending on your exposure length and you certainly should not be altering that ratio arbitrarily by applying the non-linear stretching you perform on your luminance data to bring out detail. Nope, sorry, stars are not all mostly yellow (or some other random colour you picked), they are an even mix of all color temperatures combined across a large enough field. We can argue until the cows come home about which shade objects are exactly or how saturated something should look (this is subjective), but depicting colours differently depending on exposure length or depending on your luminance processing technique belongs firmly in the era of film photography (which is fine if you want to emulate that look, but it's not very scientific and you're doing the viewing public a disservice by distorting reality and making it hard to compare things in your image and between different images). I wish more people would render their DSOs like you have done here in this faithful M8, where information conveyed by colour has been maximised. :thumbsup:

[LightningNZ]

Great work Paul, I like the sharpness of stars and you've done your best to show everything in the image in spite of the short overall exposure time. I agree though with Rick that the colour is just a bit much, and maybe the luminance is a bit overstretched at the bottom end of the histogram. Still, it's all artistic license right? Once we're using a sensor that's not our eyeball the interpretation is entirely individual.

Ivo - the stars look almost psychedelic in their colour intensity and pastel shades. I really doubt that's "real" - especially the pale blue stars, they won't match scotopic or photopic colour curves.

[Asterix2020]

Thanks Kevin, Rick, Ivo and Cam. The saturation is something I struggled with, but I'm happy with the result in the end. I think we sometimes get conditioned to what an object should look like but the colour is a result of the camera's sensitivity and stretching. Unmodded cameras don't get the red stuff as well, we know that, so which colour is correct? Modded or unmodded? Filtered CCD or not? Which filters are correct? On top of this, individuals can have different colour perception, even without a true colour vision deficiency.

Since we cannot see these colours because at these light levels we rely totally on our rods which have no colour information (disclaimer: I am an optometrist so I do know a little about retinal function, visual science and colour vision). So to me every image is "false colour" and the best representation is the from knowing what colour a certain temperature star would look to us it were bright enough to stimulate cone function and where in the colour spectrum emission lines exist for the chemicals in the nebula. I think this is what Ivo means, the colours aren't just pretty, they faithfully describe the temperature of a star or the chemical composition of a nebula. Yes the saturation can be played with, but the colour itself doesn't change.

I can't process in Photoshop, and to me you can make it look anyway you want. (Cam I don't know exactly what you mean by "stretched too much at the bottom of the histogram as I don't use histograms). I find Startools gave me different images as first, but I now don't think they are wrong. I don't decide the colour I my image, I usually select a random area of stars in the image that should have a random distribution of temperature (and therefore colours) and Startools determines the colour from that sample. I also think they are prettier :)

I think Ivo has a great piece of software and I'm only just begging to know how to use it. I think I have an advantage in that I don't have to unlearn Photoshop thought processes :) I would suggest everyone try Startools and see what it does - reprocess an image you already have and compare. There is a free trial that does everything except save your work. I have no relationship with Startools other than being a happy user.

Although I was into astronomy as a kid, even did some film photography, I've only gotten back into this in the last few months. So the above is my thoughts, but I accept I may still have a lot to learn and reserve the right to evolve my thoughts in the future :)