My God! It's Full Of Stars!

MysterX
reply to post by wildespace

 

Thanks wildespace, i suspected it might be due to exposure time, but was surprised how Earth and its Moon at their extreme distance were so well resolved, yet bright stars were not even faintly imaged.

I'd like to know how long this exposure actually was.

No worries, I like researching these kind of things.

The distance is not that extreme, and the Earth is also relatively close to the Sun, making it appear rather bright. I was more suprised to learn that the Moon would also be visible to the naked eye from Mars, and that it would be visible as separate from Earth (I assumed it's too small, too close to Earth, and would be drowned out by the Earth's light).

reply to post by Phage


Yes, i have noticed this a lot, when the sun has just dipped below the terminator and the last rays are dancing on the horizon.

Although the image taken from Mars was taken almost an hour and a half after sunset, by that time from Earth, even with the relatively enormous artificial light pollution we have in our towns and cities, i can see a lot of stars that long after sunset.

reply to post by funbox


Thank you funbox...what you've posted is exactly what i had expected to see in the image in this OP.

Lots and lots of lovely stars.

They must have removed them...i wish they hadn't done and instead just circled Earth to show us in all our cosmic glory.

Stormdancer777
OH no,
You know what this means don't you?

Go on then...what does it mean?

reply to post by wildespace


on closer inspection it appears that they are a few maybe stars/artifacts? its down to the interpretation see , and predawn is a contributing factor , mildly odd though , it doesn't look that bright, ,and with a thinner atmosphere you would expect very little turbulence/ noise

funBox

I guess Earth is visible to Mars as Venus is visible to Earth. After sunset, the only "star" you see is Venus, because its much brighter than other stars, clearly visible in dusk sky.

The stars are not visible because its not dark enough.

reply to post by funbox


Yep. Thin atmosphere would make the distortion and filtering a lot less on Mars than here. The odd browish speck here and there on the image looks like a few grains of dust on the lens to me.

(It's dusk btw, not dawn)

reply to post by MysterX

Mars does rotate a bit slower than Earth but yes, if you had been standing on Mars at the time you probably would have seen stars. Our eyes don't work like cameras though.

Here's the view that Stellarium provides. It gives Earth a magnitude of -1.1. I don't know the field of view of the image from Mars but there aren't many bright star in it. The brightest star in this Stellarium view is Alpha Aries at magnitude 2.0. Earth is more than twice as bright as that star.

reply to post by Phage


wow , nasas photos don't stand a chance against our ATS analysis , this photo just got ripped a new one

great work Phage your detective skill are bloodhoundish

drunkenPoetBOX

MysterX
reply to post by funbox

 

Thank you funbox...what you've posted is exactly what i had expected to see in the image in this OP.

Lots and lots of lovely stars.

All those specs of light in the original images are digital noise.

To echo Phage, cameras are a lot less sensitive to dim light than human eyes. Human eyes also have greater dynamic range, meaning that even in a city with lights you can see a few stars.

reply to post by funbox

wow , nasas photos don't stand a chance against our ATS analysis , this photo just got ripped a new one

That's somewhat ambiguous.
Are you saying that stars should be visible in the image from MSL based on what I posted? I don't think that's the case.

Aleister
reply to post by MysterX
Anyway, are you saying that there really are no stars when seen from other planets, that earth is unique in having stars to see? Or that the Rover isn't equipped to image stars, but its cameras work best to image their local environment and not the night sky? Or that there is no sky, and we are all living in a large container with holes cut into it? Or...worse of all....Earth is all alone in the universe, literally (except for Mars)!

edit on 8-2-2014 by Aleister because: (no reason given)

With both reading the lines and reading BETWEEN the lines...

I believe the OP is calling into question the idea that the photos may not actually be from "Mars". As in, why can we not see stars? As in, *if* for some reason the photos were faked....they apparently forgot that small detail of stars....which, as we know from earth when you are not deluged with a buttload of light pollution, the number of visible stars to the naked eye is legion......

Yepp, I believe that is what the OP was so secretly alluding to..wow, the OP is REALLY good at obscuring their ideas...aren't they ?

reply to post by wildespace


indeed , how to make a bias file without a lenscap

funBox

Thebel
I guess Earth is visible to Mars as Venus is visible to Earth. After sunset, the only "star" you see is Venus, because its much brighter than other stars, clearly visible in dusk sky.

The stars are not visible because its not dark enough.

Venus is more or less the same size as Earth, but is closer to the Sun than Earth is so it appears much brighter from earth, than we would be from Mars (Venus would be reflecting more light being closer to the Sun that we are)

We can see Venus as a bright 'star' soon after (or in many cases actually well before) sunset, but Earth is pictured quite brightly and surprisingly well resolved IMO, particularly as the Moon is easily seen as a separate point of light too.

I suppose i'm just surprised that we can see the Earth and the Moon as separate points of light, when we cannot see any other points of light in the image.

reply to post by wildespace


Hold on a mo...wasn't funbox having a laugh?

The image he posted had stars below the horizon / ridge line, so i naturally assumed he was having a giggle.

They were actual stars...but just superimposed onto the image from Mars (afaik)

reply to post by Phage


Thanks for going to that trouble.

reply to post by MysterX

I suppose i'm just surprised that we can see the Earth and the Moon as separate points of light, when we cannot see any other points of light in the image.

As I pointed out, the Earth was by far the brightest thing in that part of the sky at the time. But it's possible that in removing noise a star or two was removed from the image as well.

The Moon and Earth had an angular separation of about 5' (0.08º) so, yes, with the naked eye it would have been possible to discern them as separate objects. Just barely. Maybe.

reply to post by MysterX


Stars..........maybe simply satellite's in Earths orbit lol

reply to post by Phage


maybe , but without the exif data we do not know the shutter speed or iso setting, ill speculate and say 2" 400, but even at my lowest estimate I would have thought a few stars would have popped out

funBox

Here's a little noise-removing experiment I just did. I stacked these two images using "Difference" option in Paint Shop Pro (same way a photographer would use a "dark frame" to substract noise):
mars.nasa.gov...
mars.nasa.gov...
and enhanced brightness and contrast. Here's the result, showing what is left after the noise is removed:



It's full of stars!