APOD: NGC 4631: The Whale Galaxy (2016 Jun 03)

[geckzilla]

Perhaps this is beating a dead horse....but this isn't just any image. It was chosen as Astronomy Picture of the Day. The fact a seriously flawed image was chosen gives credibility to critics of APOD that the very best images aren't always chosen.

The editors have often shown that they are not in agreement with whatever is considered normalized within the astrophotography community. And now I see why you don't care if Martin sees your criticism or not. You were criticizing the editors all along.

[rstevenson]

Always willing to ride a dead horse, I'd like to say that I loved the image and it's been my desktop background since it was published here. On my iMac 21" monitor (calibrated) I cannot see, despite playing around wildly with the brightness and contrast controls in my image editor (GraphicConverter), the problem you're describing Robert. I don't know what that may indicate, nor how it helps, but I just thought I'd chime in.

Can you suggest a particularly egregious spot for me to zoom in on?

Rob

[geckzilla]

There is this thing among some (most?) astrophotographers to try and lay bare the Universe by bringing up the floor of the image a little bit from pure black so that the darkest parts become more easily visible. Hours upon hours are spent trying to capture the faintest details to reveal tidal streams and deeper, more distant objects. He wants it to look something more like the attached image, except for the harsh lines caused by posterization. You can see them easily just under the galactic nucleus, although if your eyes aren't trained to look for that sort of detail you might miss it. You can also see a little bit of extra light around the periphery which ideally would be flattened down since it's not actually there. Valid criticisms for sure, but in the end it's still just an aesthetic choice, and I stand by my assertion earlier that the histogram hasn't been clipped.

Edit: Looking at some DSS imagery of this galaxy, I think the hard lines under the nucleus may actually be present and not actually the posterization I thought they were. Disturbed galaxies don't always have a smooth transition.

[starsurfer]

No I'm not rigid on this. I have a lot of experience processing images (probably more than you) so I do know what I'm talking about. You seem compelled to defend the processing for some reason I'm not sure about. I know Martin (although I no longer have his contact info) as a great image processor so that is why this image got my attention. As long as my comments are appropriate to the image I think I'll continue to post them here. Sorry if that offends you.

Offends me? All I'm saying is that it's possible he wants his images to look exactly how he processes them. Not how Robert Gendler would have processed them—how he wants them. It's also possible that something else is up.

And I didn't mean for you to stop posting your comments here. I mean that your criticism can't help him if he doesn't see it.

Perhaps this is beating a dead horse....but this isn't just any image. It was chosen as Astronomy Picture of the Day. The fact a seriously flawed image was chosen gives credibility to critics of APOD that the very best images aren't always chosen.

I think the point Rob is trying to make is that you're used to things being a particular way and then when they change unexpectedly without an apparent good reason (in this case a processing workflow and the "darkness" of space), you want things to go back to how they were, I think it's kinda reverse nostalgia type thing?

@Rob: APOD isn't about the "best" images, it's not a competition. It's just about showing people the images the editors consider interesting to them.

@geckzilla: I love your diplomatic approach and tactfulness, I've always considered you a fair and just person and stand by my position that you are a nice person!

[starsurfer]

There is this thing among some (most?) astrophotographers to try and lay bare the Universe by bringing up the floor of the image a little bit from pure black so that the darkest parts become more easily visible. Hours upon hours are spent trying to capture the faintest details to reveal tidal streams and deeper, more distant objects. He wants it to look something more like the attached image, except for the harsh lines caused by posterization. You can see them easily just under the galactic nucleus, although if your eyes aren't trained to look for that sort of detail you might miss it. You can also see a little bit of extra light around the periphery which ideally would be flattened down since it's not actually there. Valid criticisms for sure, but in the end it's still just an aesthetic choice, and I stand by my assertion earlier that the histogram hasn't been clipped.

Edit: Looking at some DSS imagery of this galaxy, I think the hard lines under the nucleus may actually be present and not actually the posterization I thought they were. Disturbed galaxies don't always have a smooth transition.

I much prefer this version to the original version. I can clearly see many background galaxies easily now! One of the reasons some people might make the background dark is to hide any artifacts that might exist.

[geckzilla]

@geckzilla: I love your diplomatic approach and tactfulness, I've always considered you a fair and just person and stand by my position that you are a nice person!

I get pretty salty sometimes. You must have missed it.

[rgendler]

Perhaps this is beating a dead horse....but this isn't just any image. It was chosen as Astronomy Picture of the Day. The fact a seriously flawed image was chosen gives credibility to critics of APOD that the very best images aren't always chosen.

The editors have often shown that they are not in agreement with whatever is considered normalized within the astrophotography community. And now I see why you don't care if Martin sees your criticism or not. You were criticizing the editors all along.

Lol...you know Judy....your responses are so immature and thin skinned, I'm really surprised, especially since I know you are no stranger to doling out criticism yourself. Apparently you want to turn my critical technical comments into something personal. Good luck with that.

[geckzilla]

Lol...you know Judy....your responses are so immature and thin skinned, I'm really surprised, especially since I know you are no stranger to doling out criticism yourself. Apparently you want to turn my critical technical comments into something personal. Good luck with that.

I'm not sure when I lost the benefit of the doubt with you.

[rgendler]

There is this thing among some (most?) astrophotographers to try and lay bare the Universe by bringing up the floor of the image a little bit from pure black so that the darkest parts become more easily visible.

BTW astrophotographers DO NOT bring up the floor of an image from pure black. The background data is NEVER pure black. There are plenty of pixels in any adequately exposed area of the night sky besides noise. However some astrophotographers render it black (either by clipping or supressing shadow data). Rendering the background pure black is considered by almost all experienced astrophotographers as not a good practice either informationally or aesthetically. That said I realize you will either throw the comment back in my face or make it personal in some way.

[geckzilla]

The background data will have a low point which, in order to maximize the dynamic range of an image, can be considered the black point. In practice, though, most people have issues seeing the darkest of those values and so it is prudent to raise it up from that slightly at a loss of range.