Starship Asterisk*

by **geckzilla** » Tue Jun 07, 2016 5:31 pm

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.

by **rgendler** » Tue Jun 07, 2016 5:22 pm

geckzilla wrote: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.

by **geckzilla** » Tue Jun 07, 2016 5:12 pm

rgendler wrote: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.

by **rgendler** » Tue Jun 07, 2016 5:06 pm

geckzilla wrote:
rgendler wrote: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.

by **geckzilla** » Tue Jun 07, 2016 5:04 pm

starsurfer wrote:@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.

by **starsurfer** » Tue Jun 07, 2016 4:58 pm

geckzilla wrote: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.

by **starsurfer** » Tue Jun 07, 2016 4:40 pm

rgendler wrote:
geckzilla wrote:
rgendler wrote: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!

by **geckzilla** » Tue Jun 07, 2016 2:42 pm

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.

by **rstevenson** » Tue Jun 07, 2016 2:25 pm

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

by **geckzilla** » Tue Jun 07, 2016 2:10 pm

rgendler wrote: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.

by **rgendler** » Tue Jun 07, 2016 12:05 pm

geckzilla wrote:
rgendler wrote: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.

by **geckzilla** » Sun Jun 05, 2016 11:54 pm

rgendler wrote: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.

by **rgendler** » Sun Jun 05, 2016 11:50 pm

geckzilla wrote:
rgendler wrote:It's not just the background. The transition of halo to black background is too abrupt and unnatural. We have dozens of computers where I work all with calibrated monitors and the image looks the same for me. So if you think it looks great then I suggest you look into calibrating your monitor or buy a new one.
No thanks. I'll take the bias I'm used to. Besides, your monitors are all calibrated to look the same as each other. Of course the image looks the same to you on all of them. In reality, most people don't have that. I looked at my images on a bunch of uncalibrated monitors to get an idea of what I needed to do with them.

Personally, I think you are ... very rigid in your thinking on this. There is nearly always room for improvement, but you seem to see it as some kind of unforgivable flaw. Maybe you should email him instead of commenting here. I don't think he's reading the comments.

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.

by **geckzilla** » Sun Jun 05, 2016 10:53 pm

rgendler wrote:It's not just the background. The transition of halo to black background is too abrupt and unnatural. We have dozens of computers where I work all with calibrated monitors and the image looks the same for me. So if you think it looks great then I suggest you look into calibrating your monitor or buy a new one.

No thanks. I'll take the bias I'm used to. Besides, your monitors are all calibrated to look the same as each other. Of course the image looks the same to you on all of them. In reality, most people don't have that. I looked at my images on a bunch of uncalibrated monitors to get an idea of what I needed to do with them.

Personally, I think you are ... very rigid in your thinking on this. There is nearly always room for improvement, but you seem to see it as some kind of unforgivable flaw. Maybe you should email him instead of commenting here. I don't think he's reading the comments.

by **rgendler** » Sun Jun 05, 2016 12:52 pm

geckzilla wrote:
starsurfer wrote:The image was originally like this and has not been altered by APOD, that is something they never do. For some reason, Martin changed his processing approach last year and all his galaxy images now have really dark backgrounds. I also agree with you as a lot of information for background galaxies is lost.
At least one of the editors has modified images in the past, actually. I think he stopped, though, other than perhaps a color profile going missing from time to time.

It's not just the background. The transition of halo to black background is too abrupt and unnatural. We have dozens of computers where I work all with calibrated monitors and the image looks the same for me. So if you think it looks great then I suggest you look into calibrating your monitor or buy a new one.

by **geckzilla** » Sun Jun 05, 2016 11:34 am

starsurfer wrote:The image was originally like this and has not been altered by APOD, that is something they never do. For some reason, Martin changed his processing approach last year and all his galaxy images now have really dark backgrounds. I also agree with you as a lot of information for background galaxies is lost.

At least one of the editors has modified images in the past, actually. I think he stopped, though, other than perhaps a color profile going missing from time to time.

by **starsurfer** » Sun Jun 05, 2016 6:56 am

Also stellar streams associated with this galaxy are mentioned, two separate pro-am collaborations detected them separately. Two images show them clearly, this one by Fabian Neyer and another by Karel Teuwen.

by **starsurfer** » Sun Jun 05, 2016 6:54 am

rgendler wrote:
geckzilla wrote:
robgendler wrote:Martin is a fine astrophotographer but the image is severely clipped. There's absolutely no shadow data. The background is black which is a major flaw in processing.
It's there, it's just not stretched. I'd call it an aesthetic choice rather than a flaw.

Well it was a poor (and surprising) processing choice. I really wonder if Martin made this choice or the image was manipulated by APOD staff. Hard to believe someone as experienced as Martin would clip the image that much.

The image was originally like this and has not been altered by APOD, that is something they never do. For some reason, Martin changed his processing approach last year and all his galaxy images now have really dark backgrounds. I also agree with you as a lot of information for background galaxies is lost.

by **geckzilla** » Sat Jun 04, 2016 9:26 pm

rgendler wrote:
geckzilla wrote:
robgendler wrote:Martin is a fine astrophotographer but the image is severely clipped. There's absolutely no shadow data. The background is black which is a major flaw in processing.
It's there, it's just not stretched. I'd call it an aesthetic choice rather than a flaw.
Well it was a poor (and surprising) processing choice. I really wonder if Martin made this choice or the image was manipulated by APOD staff. Hard to believe someone as experienced as Martin would clip the image that much.

Could be that he got a new monitor. I've long had a monitor that shows a lot of brightness in the shadows and images like this look fine on my screen. I've always had to compensate for the general population having much darker monitors by pushing the brightness up to the point that things look a little washed out on my screen. Sometimes I'll still make something that just looks good to me and forget everyone else, though. I always laugh (or at least grin a little) when I see that someone has taken the selection tool and paint bucket to fill the background with pure black. It's so obvious on my screen, but most people clearly can't see it. Martin's picture looks great to me.

by **rgendler** » Sat Jun 04, 2016 7:13 pm

geckzilla wrote:
robgendler wrote:Martin is a fine astrophotographer but the image is severely clipped. There's absolutely no shadow data. The background is black which is a major flaw in processing.
It's there, it's just not stretched. I'd call it an aesthetic choice rather than a flaw.

Well it was a poor (and surprising) processing choice. I really wonder if Martin made this choice or the image was manipulated by APOD staff. Hard to believe someone as experienced as Martin would clip the image that much.

by **Ann** » Sat Jun 04, 2016 5:25 am

heehaw wrote:Yellowish core? Does not seem to be at the center. What the heck is it?

: Click to view full size image

M101 and NGC 5474.
Photo: Thomas V. Davis.

A galaxy is not a solid structure, and the core may "slosh around" inside it. Or, if you'd rather put it like that, the fluffy arms may slosh this way and that around the core.

Check out this picture of M10 and its small satellite galaxy NGC 5474. In both galaxies, the core is visibly displaced from the center.

Ann

by **heehaw** » Fri Jun 03, 2016 11:14 pm

Yellowish core? Does not seem to be at the center. What the heck is it?

by **Boomer12k** » Fri Jun 03, 2016 11:11 pm

This image looks more like a Dolphin....

Great Shot.
:---[===] *

by **geckzilla** » Fri Jun 03, 2016 9:25 pm

robgendler wrote:Martin is a fine astrophotographer but the image is severely clipped. There's absolutely no shadow data. The background is black which is a major flaw in processing.

It's there, it's just not stretched. I'd call it an aesthetic choice rather than a flaw.

by **robgendler** » Fri Jun 03, 2016 8:30 pm

Martin is a fine astrophotographer but the image is severely clipped. There's absolutely no shadow data. The background is black which is a major flaw in processing.

Starship Asterisk*

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

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