APOD: ISON, Mars, Regulus (2013 Oct 17)

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Expand view Topic review: APOD: ISON, Mars, Regulus (2013 Oct 17)

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Chris Peterson » Mon Oct 21, 2013 3:43 pm

StarCuriousAero wrote:Unfortunately I have limited options on my work computer, I can't install anything on my own. Although, the monitor does have built in adjustments for picking sRGB, 9300K, 7500K, 6500K, 5400K, or a user specified setting, they all seem to be pretty worthless. Laptop looks better no matter how much I adjust the color, but that might be because it's new and the monitor is at least 5 years old.
It may be that the laptop has a better display. But I'd guess it's actually because the laptop has a color profile installed. They usually do, since the screen and computer are part of the same system, so manufacturers tend to ship them with all the right drivers- including the color profile- already installed.

Desktop computers don't come with anything except standard generic color profiles, and you need to apply a custom profile when you attach a new monitor. Many times this step is skipped, so you end up using a generic profile that is a poor match to the monitor.

If you're using a Windows 7 computer at work, try the Color Management app in Control Panel. Unless you're heavily locked down, that can be used to create a color profile, and doesn't typically require any administrative privileges.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by geckzilla » Mon Oct 21, 2013 3:40 pm

Does sunlight ever shine on the monitor, Star? I wonder if the plastic which should be clear has yellowed and darkened due to exposure to UV light. I always wonder about that and whether it's possible for dust to get inside an LCD screen and cover the screen between the backlight or even the backlight itself and cause dimming over time. I would hope they are sealed well enough to avoid such a thing but haven't ever investigated it. I've got one monitor where the backlight behaves much like any old office fluorescent bulb that takes forever to warm up. It'd be fine if the just the light were replaced but I don't know if that's a good idea.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by StarCuriousAero » Mon Oct 21, 2013 3:32 pm

Chris Peterson wrote:
StarCuriousAero wrote:I think it may be worth noting that some monitors might not be capable of seeing Leo I, for instance, at work I have a monitor used in conjunction with a laptop, and the monitor can't see it no matter how much I fiddle with the brightness/contrast/color, but the laptop screen shows it just fine. For especially colorful images I always have to drag my APOD window over to my laptop to get full enjoyment, the difference is astounding sometimes.
The actual screen on a laptop is likely to be inferior to that of a standalone monitor. That said, adjusting the brightness and contrast on a monitor- especially a LCD monitor- is only of limited value. What is important is having the right color profile installed on your computer. Using the one supplied with the monitor (but often left uninstalled) is a good start, although using a hardware calibrator is best.
Unfortunately I have limited options on my work computer, I can't install anything on my own. Although, the monitor does have built in adjustments for picking sRGB, 9300K, 7500K, 6500K, 5400K, or a user specified setting, they all seem to be pretty worthless. Laptop looks better no matter how much I adjust the color, but that might be because it's new and the monitor is at least 5 years old.

*Edited for spelling.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by DavidLeodis » Fri Oct 18, 2013 4:50 pm

Thanks all for your responses to my comment about the Leo 1 dwarf galaxy, which are appreciated. :)

From the image brought up through Ann's link I now realise that Leo 1 is a wispy faint blue area in the APOD. I still however think that it is too faint to have been noted in the explanation in that it looks just like some other wispy faint blue areas around Regulus, though admittedly just above those.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Chris Peterson » Fri Oct 18, 2013 4:39 pm

StarCuriousAero wrote:I think it may be worth noting that some monitors might not be capable of seeing Leo I, for instance, at work I have a monitor used in conjunction with a laptop, and the monitor can't see it no matter how much I fiddle with the brightness/contrast/color, but the laptop screen shows it just fine. For especially colorful images I always have to drag my APOD window over to my laptop to get full enjoyment, the difference is astounding sometimes.
The actual screen on a laptop is likely to be inferior to that of a standalone monitor. That said, adjusting the brightness and contrast on a monitor- especially a LCD monitor- is only of limited value. What is important is having the right color profile installed on your computer. Using the one supplied with the monitor (but often left uninstalled) is a good start, although using a hardware calibrator is best.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by StarCuriousAero » Fri Oct 18, 2013 4:24 pm

Chris Peterson wrote:
DavidLeodis wrote:In the explanation to the image it states "Just above Regulus, the very faint smudge of light is actually the Leo I dwarf galaxy, 800,000 light-years away and almost lost in the glare of the bluish hued bright star.". It must be very faint as I cannot make it out, so I wonder if anybody else is having trouble spotting the "very faint smudge"? I wonder if those who claim they see it would have noticed it if it had not been mentioned in the explanation? Unless it definitely needed doing I think mentioning such a very faint thing was unnecessary.
I see the smudge very easily. If you don't, your monitor needs adjusting. It is certainly obvious enough that without explanation, we'd have people inquiring here what it is.

That said, I'm skeptical we are seeing it with anything like the natural brightness is should exhibit. The fact that it is the same color as the light from Regulus reveals that it has been enhanced by some sort of stretching operation that emphasized the blue channel. It is in the right place, and I'm sure we are really seeing the galaxy, but it isn't a good representation. But this APOD has some serious color problems (the image that Ann referred to earlier is much more accurate- and while showing similar limiting magnitude, doesn't show the dwarf galaxy). I'm not sure why the blue is so elevated in Pete's image- even Mars is magenta! And Regulus is far too blue, as is the comet (again, the other image shows a much more accurate greenish color, typical of cyanogen, in the comet tail).
I think it may be worth noting that some monitors might not be capable of seeing Leo I, for instance, at work I have a monitor used in conjunction with a laptop, and the monitor can't see it no matter how much I fiddle with the brightness/contrast/color, but the laptop screen shows it just fine. For especially colorful images I always have to drag my APOD window over to my laptop to get full enjoyment, the difference is astounding sometimes.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Chris Peterson » Fri Oct 18, 2013 3:17 pm

Ann wrote:This is a good picture of bright star Regulus and dwarf galaxy Leo 1. The colors seem believable, too.

Given the brightness of Leo and the faintness of the galaxy, it must be very hard to photograph these two objects in a way that does both of them justice.
That's a very good image. Reflective optics offer many advantages, but imaging objects like this isn't one of them. Most telescope mirrors have a degree of surface roughness that creates a halo around bright, overexposed stars. And most reflective optics aren't cleaned very often (because it is so easy to damage the surfaces), which further increases scattered light. The image you link above was produced with a good quality refractor, which will generally do a much better job when you have a dim object very close to a bright one. Of course, that advantage comes with the disadvantage of a small aperture, and therefore a longer required exposure time.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Ann » Fri Oct 18, 2013 2:59 pm

This is a good picture of bright star Regulus and dwarf galaxy Leo 1. The colors seem believable, too.

Given the brightness of Leo and the faintness of the galaxy, it must be very hard to photograph these two objects in a way that does both of them justice. Bear in mind that the B magnitude of Regulus is about 1.4, all of this light for all intents and purposes concentrated in a single point. The B magnitude of Leo 1 is about 11.2, almost ten magnitudes fainter than Regulus. But this feeble light is also spread out over about 12 X 9 arcminutes. Consider, too, what the Morphological Catalog of Galaxies (MCG) says about the surface brightness of Leo 1. The MCG ranks the surface brightness of galaxies from 1 to 6, where 1 is the brightest and 6 is the faintest. Almost all well-known galaxies are given a number 1, suggesting a high surface brightness. That includes a galaxy like M33, which is a relatively faint face-on galaxy. So what about Leo 1? It is given a 4 by the MCG.

Really, Leo 1 is faint!!!

Ann

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Chris Peterson » Fri Oct 18, 2013 2:21 pm

BMAONE23 wrote:It is about 4 times the span of the visually brightest part of the star above it and about the same size, so to me it appears to resemble a lens reflection
It does look like a lens reflection, but given its location and size, I think it actually is Leo I. Also, the image was made with a simple telescope which doesn't offer many surfaces that could produce internal reflections. There is a good deal of scatter (possibly from a dirty primary), but that's all. Internal reflections are typically seen in camera lenses, which have many air gaps between elements.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by BMAONE23 » Fri Oct 18, 2013 2:10 pm

It is about 4 times the span of the visually brightest part of the star above it and about the same size, so to me it appears to resemble a lens reflection

-----
----- Faint Mass





____
____ Regulus

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Chris Peterson » Fri Oct 18, 2013 2:07 pm

DavidLeodis wrote:In the explanation to the image it states "Just above Regulus, the very faint smudge of light is actually the Leo I dwarf galaxy, 800,000 light-years away and almost lost in the glare of the bluish hued bright star.". It must be very faint as I cannot make it out, so I wonder if anybody else is having trouble spotting the "very faint smudge"? I wonder if those who claim they see it would have noticed it if it had not been mentioned in the explanation? Unless it definitely needed doing I think mentioning such a very faint thing was unnecessary.
I see the smudge very easily. If you don't, your monitor needs adjusting. It is certainly obvious enough that without explanation, we'd have people inquiring here what it is.

That said, I'm skeptical we are seeing it with anything like the natural brightness is should exhibit. The fact that it is the same color as the light from Regulus reveals that it has been enhanced by some sort of stretching operation that emphasized the blue channel. It is in the right place, and I'm sure we are really seeing the galaxy, but it isn't a good representation. But this APOD has some serious color problems (the image that Ann referred to earlier is much more accurate- and while showing similar limiting magnitude, doesn't show the dwarf galaxy). I'm not sure why the blue is so elevated in Pete's image- even Mars is magenta! And Regulus is far too blue, as is the comet (again, the other image shows a much more accurate greenish color, typical of cyanogen, in the comet tail).

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by DavidLeodis » Fri Oct 18, 2013 1:38 pm

In the explanation to the image it states "Just above Regulus, the very faint smudge of light is actually the Leo I dwarf galaxy, 800,000 light-years away and almost lost in the glare of the bluish hued bright star.". It must be very faint as I cannot make it out, so I wonder if anybody else is having trouble spotting the "very faint smudge"? I wonder if those who claim they see it would have noticed it if it had not been mentioned in the explanation? Unless it definitely needed doing I think mentioning such a very faint thing was unnecessary.

PS. It's good to see the APOD back to normal. Thanks to all for keeping it going. :)

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by geckzilla » Fri Oct 18, 2013 2:24 am

Tonight they talked briefly about today's APOD on the Hubble Hangout! Fun little gathering of astronomers talking about ISON.
Click to play embedded YouTube video.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by metamorphmuses » Fri Oct 18, 2013 2:22 am

Yes, indeed... Welcome Back!

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by yellowbag » Fri Oct 18, 2013 2:13 am

i am so happy to have apod back! there was a link that was supposed to open the site way back, what happened to it , it didn't work at all. i missed apod so much! :D

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Beyond » Fri Oct 18, 2013 1:51 am

To me the comet looks blue-green and then green blue, which isn't as drastic a change as Mars and Regulus. But I'm not as familiar with filter effects as others are. :no:

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Ann » Fri Oct 18, 2013 12:54 am

Beyond wrote:
Ann wrote:An interesting "comment" on today's APOD is this image of Mars, Regulus and Comet ISON by Nuitsacrees. As you can see, the color balance of Nuitsacrees' image is quite different from the color balance of the APOD. Comet ISON is again very faint and can be seen at about 1 o'clock.

Ann
Well that's a bit strange (to me anyway), the comet color seems about the same in both photos, even though the Mars and Regulus colors are different in both photos. How come :?: :?:
Actually the color of the comet isn't the same. ISON looks quite blue in today's APOD, but decidedly green in Nuitsacrees' image.

Ann

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Beyond » Fri Oct 18, 2013 12:26 am

Ann wrote:An interesting "comment" on today's APOD is this image of Mars, Regulus and Comet ISON by Nuitsacrees. As you can see, the color balance of Nuitsacrees' image is quite different from the color balance of the APOD. Comet ISON is again very faint and can be seen at about 1 o'clock.

Ann
Well that's a bit strange (to me anyway), the comet color seems about the same in both photos, even though the Mars and Regulus colors are different in both photos. How come :?: :?:

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Ann » Fri Oct 18, 2013 12:18 am

An interesting "comment" on today's APOD is this image of Mars, Regulus and Comet ISON by Nuitsacrees. As you can see, the color balance of Nuitsacrees' image is quite different from the color balance of the APOD. Comet ISON is again very faint and can be seen at about 1 o'clock.

Ann

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Arizona Jeep Guy » Fri Oct 18, 2013 12:08 am

It made my day that you guys were back online! :D

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by DavidGovett » Thu Oct 17, 2013 11:52 pm

Welcome back.
I missed the site.

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Boomer12k » Thu Oct 17, 2013 11:40 pm

Hey....Regular APOD link is working again....Great.....My Tax Dollars at work!!!!

Great Picture....Go, Comet, Go....

:---[===] *

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by appreciator » Thu Oct 17, 2013 9:20 pm

Welcome back NASA! :)

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by owlice » Thu Oct 17, 2013 7:36 pm

Weatherman wrote:Sorry, but I thought it was pretty disgusting for whoever to go in and intentionally remove the website. If you don't want to update it every day because you can't do it on your off time at home fine, but to take the time and MONEY to cut the link? Time for tar and feathers with government idiots. :evil:
http://asterisk.apod.com/viewtopic.php?f=28&t=32210

Re: APOD: ISON, Mars, Regulus (2013 Oct 17)

by Anthony Barreiro » Thu Oct 17, 2013 7:26 pm

For those of us who have been trying to observe Comet ISON, this picture is very helpful in showing what it might look like currently: very small and very faint, if you can see it at all.

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