Starship Asterisk*

by **Ron-Astro Pharmacist** » Thu Mar 26, 2015 2:23 pm

Thanks to both of you. I really want to learn more about the images we see. To do that I suspect I'll have to learn the steps between the shooting and the end product. The videos help but but unlocking the data from your own images will go a longer way towards understanding these. Ron

by **Chris Peterson** » Thu Mar 26, 2015 12:55 am

Nitpicker wrote:I think Chris was talking about a plugin that doesn't even require you to download the image, let alone upload it somewhere else. Sounds handy.

Right. I have this one installed in Firefox, and I can just right-click any image and get the Exif data.

Also useful is this site (but there are many similar ones) that you can just paste in a link to an image already on the web. This is usually simpler than downloading an image and then uploading it to an analyzer site, or downloading the image and opening it in a local viewer (or examining the file properties in Windows).

Exif data is only reliable if you know all the processes the file has been through. For anyone else, it can easily be unreliable or misleading.

Definitely. I usually strip it from images I post, and it's common to see JPEGs with no header data. And as you say, processing will often change many fields. Usually, however, the camera information is persistent, as is the exposure information if the image isn't a stack.

by **Nitpicker** » Thu Mar 26, 2015 12:42 am

Ron, I didn't look too closely, but it looks like that web utility requires you to download the image off the original website and upload it to theirs.

I think Chris was talking about a plugin that doesn't even require you to download the image, let alone upload it somewhere else. Sounds handy.

When I check for Exif data, I simply download the image file to my machine and right-click on Properties in Windows Explorer. All the Exif details appear on the Details tab. (At least in Windows 7, but probably the same in most other versions.) You can manually modify/delete the Exif data from this tab, too (and a lot of software will meddle with the Exif data automatically, as well). Exif data is only reliable if you know all the processes the file has been through. For anyone else, it can easily be unreliable or misleading.

by **ta152h0** » Thu Mar 26, 2015 12:21 am

fhis could be an issue with images of people

by **Ron-Astro Pharmacist** » Wed Mar 25, 2015 10:59 pm

I don't know if this will extinguish the "file" but it might help us photo unenlightened. Lot's to learn so hints are always welcome because it was "Beyond" me too. Thanks Chris – we always wonder how you do your magic.

Click to play embedded YouTube video.

by **Beyond** » Wed Mar 25, 2015 6:55 pm

Chris Peterson wrote:
Beyond wrote:I don't take photographs anymore, or even have a camera, since my pocket camera zoomed in to a floor close-up a couple of years ago, after it teed me off. Besides, i hear a lot about all that stuff in the conversations that take place. I just don't have any interest in photography, or all the things that go into making pictures, just like i don't have any interest in politicians or the making of them, even though they both exist.
That's sad.

Not for me. My interests lie elsewhere, but even then, i don't get into many details at all.

by **Chris Peterson** » Wed Mar 25, 2015 6:45 pm

Beyond wrote:I don't take photographs anymore, or even have a camera, since my pocket camera zoomed in to a floor close-up a couple of years ago, after it teed me off. Besides, i hear a lot about all that stuff in the conversations that take place. I just don't have any interest in photography, or all the things that go into making pictures, just like i don't have any interest in politicians or the making of them, even though they both exist.

That's sad.

by **Beyond** » Wed Mar 25, 2015 6:40 pm

Chris Peterson wrote:
Beyond wrote:I guess I'm one of the most trivial image viewers, as i have no idea on how to view header information. But then, i don't have a use for any of the information anyway.
I don't really see how anybody interested in images couldn't sometimes be interested in the details that have gone into making them.

I don't take photographs anymore, or even have a camera, since my pocket camera zoomed in to a floor close-up a couple of years ago, after it teed me off. Besides, i hear a lot about all that stuff in the conversations that take place. I just don't have any interest in photography, or all the things that go into making pictures, just like i don't have any interest in politicians or the making of them, even though they both exist.

by **Chris Peterson** » Wed Mar 25, 2015 6:19 pm

Beyond wrote:I guess I'm one of the most trivial image viewers, as i have no idea on how to view header information. But then, i don't have a use for any of the information anyway.

I don't really see how anybody interested in images couldn't sometimes be interested in the details that have gone into making them.

by **Beyond** » Wed Mar 25, 2015 6:15 pm

I guess I'm one of the most trivial image viewers, as i have no idea on how to view header information. But then, i don't have a use for any of the information anyway.

by **Chris Peterson** » Wed Mar 25, 2015 5:46 pm

Bill in Tennessee wrote:
Chris Peterson wrote:The image header says it was a 224 second exposure, which seems reasonable.
Well OK, I'm looking at the page again and STILL don't see the "224 second exposure" but I'll take your word for it.

It's in the Exif file header of the image itself. Embedded. The camera type, date and time, exposure information, focal length, lots of information. Anything but the most trivial image viewers will provide the ability to display the header contents. There are also browser plugins you can use to view Exif headers, and online viewers that you can simply provide the URL of an image.

by **Bill in Tennessee** » Wed Mar 25, 2015 5:32 pm

Chris Peterson wrote:
Bill in Tennessee wrote:OK, so how long was the shutter open on this shot? I'm wondering because the stars are showing movement so I'm guessing several minutes? Please explain.
The image header says it was a 224 second exposure, which seems reasonable.

Well OK, I'm looking at the page again and STILL don't see the "224 second exposure" but I'll take your word for it.

by **Ron-Astro Pharmacist** » Mon Mar 23, 2015 7:07 pm

ta152h0 wrote:The boss must be out taking a break today

Fortunately as Safety Ambassador for our building I just undistinguishly e-mailed it to him too under the topic, "Fire Awareness". Great 500 posts - I can retire. From "work" that is - you all will have to endure more "play" perhaps.

by **ta152h0** » Mon Mar 23, 2015 6:46 pm

The boss must be out taking a break today

by **Ron-Astro Pharmacist** » Mon Mar 23, 2015 6:32 pm

I'm sure NASA engineers know what they're doing when it comes to figuring out "how" to make (or break) a good fire". I, on the other hand, would be better described as below.

by **Ron-Astro Pharmacist** » Mon Mar 23, 2015 4:37 pm

The Atlas V and the Saturn V sound similar and may tell a similar story although quite dissimilar in characteristics.

http://en.wikipedia.org/wiki/Comparison ... ch_systems

Total weight at liftoff the Saturn V, at around 3 million kg versus for the Atlas V at 300,000 kg, and could lift 118,000 kg versus 9,000 to 19,000 kg respectively (depending on the various versions) to low Earth orbit according the above source. It seems a pretty similar efficiency rate. Have modern rocket engines and propellants not improved much over the years?

Maybe my math is "Mickey?" The Saturn V was definitely Mighty! Logically – I could be also be:

: Mickey on Mercury.jpg (11.12 KiB) Viewed 5473 times

Edit Addendum: http://arstechnica.com/science/2013/04/ ... of-thrust/

by **BPCooper** » Mon Mar 23, 2015 3:29 pm

Yes that is correct, 224 seconds. Thank you.

by **Chris Peterson** » Mon Mar 23, 2015 3:04 pm

Bill in Tennessee wrote:OK, so how long was the shutter open on this shot? I'm wondering because the stars are showing movement so I'm guessing several minutes? Please explain.

The image header says it was a 224 second exposure, which seems reasonable.

by **ta152h0** » Mon Mar 23, 2015 2:41 pm

And I thought this was an image taken a split second after totality

by **Bill in Tennessee** » Mon Mar 23, 2015 12:32 pm

OK, so how long was the shutter open on this shot? I'm wondering because the stars are showing movement so I'm guessing several minutes? Please explain.

by **hoohaw** » Mon Mar 23, 2015 9:11 am

"No species other than human can even comprehend what is going on, nor could any human just a millennium ago." A powerful statement! We must be enormously proud, and extremely grateful!

by **bystander** » Mon Mar 23, 2015 5:06 am

http://asterisk.apod.com/viewtopic.php?t=34533

by **APOD Robot** » Mon Mar 23, 2015 4:05 am

Atlas V Launches MMS

Explanation: Birds don't fly this high. Airplanes don't go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description. Pictured above, an Atlas V rocket lifts off carrying NASA's Magnetospheric Multiscale Mission into Earth orbit 10 days ago to study the workings of the magnetosphere that surrounds and protects the Earth. From a standing start, the 300,000 kilogram rocket ship left to circle the Earth where the outside air is too thin to breathe. Rockets bound for space are now launched from somewhere on Earth about once a week.

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Starship Asterisk*

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