Starship Asterisk*

gam wrote:The stars in the background do not appear to have moved over the six-hour exposure. Why not?

gam wrote:All the meteor tracks appear to pass through the same sequence of colors. Why is that?

The stars in the background do not appear to have moved over the six-hour exposure. Why not?

The moderator says that the apparent divergence of parallel meteor tracks is due perspective. Rays of sunlight from clouds also seem to diverge for the same reason, I suppose, which gives one a clue about how great the distances of even earthly phenomena can be.

León wrote:I wonder meteor showers have been used to set dates by the ancients.

Known since ancient meteorites attributed to the stones that were thrown the gods have not been marteria of analysis.

In front in the center of the image of my personal collection of stones is possible to observe a meteor.

In front in the center of the image of my personal collection of stones is possible to observe a meteor.

I see it. But the proper term is meteorite. A meteor is a flash in the sky.

FreekOne wrote:
I was out two nights in a row, stargazing outside Timisoara, Romania - just a couple hundred miles from where the picture was actually taken. There weren't really as many meteorites as I saw in previous years but it was worth it, nevertheless ! During both nights I saw quite a few meteorites streaking the sky TOWARDS the radiant point in Perseus, rather than FROM it. I am now curious whether these were Perseid meteorites and if so, what is the explanation for their backwards direction ?

http://antwrp.gsfc.nasa.gov/apod/ap090511.html wrote:

[color=#00FF40][b]S[/b][/color]outhern [color=#00FF40][b]D[/b][/color]elta [color=#00FF40][b]A[/b][/color]quariids & Alpha [color=#0080FF][b]CAP[/b][/color]ricornids are late July showers on the opposite side of the sky map from the [color=#FFAF00][b]PER[/b][/color]seids

---

--------------------------------------------------------------------------------------------
Name  ↓                 Dates  ↓       Peak dates↓     R.A.    Dec. (km/s) ZHR   Rating
---------------------------------------------------------------------------------------------
Alpha Capricornids     3 July-15 August    30 July    20:28    -10    23     4   Medium
S. Delta Aquariids    12 July-19 August    28 July    22:36    -16    41    20   Strong
Perseids              17 July-24 August    12 August  03:04    +58    59    90   Strong
---------------------------------------------------------------------------------------------

Case wrote:

gam wrote:The stars in the background do not appear to have moved over the six-hour exposure. Why not?

It is a 30 second exposure, one of a series of exposures over a period of 6 hours. There are some image details in the EXIF data.

DavidLeodis wrote:... I am wondering Case how you were able to get the EXIF data, as my attempts failed. However, using your link, I see that the image was taken on August 13 2010 at 12:51:25 AM (timezone not specified). ...

rstevenson wrote:

DavidLeodis wrote:... I am wondering Case how you were able to get the EXIF data, as my attempts failed. However, using your link, I see that the image was taken on August 13 2010 at 12:51:25 AM (timezone not specified). ...

I'm not sure how Case did it, but when I open that image in GraphicConverter, my fave Mac OS X graphic tool, I can choose to Copy EXIF Data As Text (under the Edit menu) and I get a large quantity of information when I paste it into any text editor. I assume any good image program can do something similar. For example, in PhotoShop all of this info was contained in multiple tabs inside the File Info... window, from the File menu.

Rob

DavidLeodis wrote:I know I can get EXIF Data (or at least some of it) by clicking on Properties on my digital camera images and also some online images but that did not work for this APOD. I only have a basic image editing program and that did not give an EXIF Data for this APOD. I clearly need a better such program! The amount of information in EXIF data can be quite staggering! :)

DavidLeodis wrote:[The} image editing program did not give an EXIF Data for this APOD.

Case wrote:

DavidLeodis wrote:[The} image editing program did not give an EXIF Data for this APOD.

The image on the APOD page (1) doesn't have EXIF data, but the "high res" click-through image (2) does have the EXIF data embedded. Note that the image manipulation (stacking etc.) means that the EXIF data is only true for one of the source images used in this composite.

P.S. the Info window for Preview (the Mac OS image and PDF viewer) also shows (some) EXIF data in one of the tabs. It loads quite a bit faster than a full image editor, if you want just a quick peek.

I thought it was quite cool to find the online EXIF tool at http://regex.info/exif.cgi, both for sharing (linking) and not-downloading-anything.

DavidLeodis wrote:... (though it did not give a date ).

I like to try to find the date when APOD images were taken as that is often not given yet lots of technical photographic data is in the information with images.