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AutoClub
2007-Jun-28, 12:01 AM
Hi guys – Here’s an image I captured the other night of a -7 Magnitude Iridium 84 flare visible here in Los Angeles.

Image capture data: Date: June 25, 2007, 10:34 p.m. Pacific Daylight Time; Camera – Canon 20D; Lens – EF 28-135mm IS f/3.5-5.6, set at 28mm focal length; Other camera settings – ISO 800, Sunny (daylight) white balance, 30 seconds exposure at f/8.0, Shutter speed set to Bulb, Image size – Medium (1728x1158) .jpg format, Manual focus, Programmable remote shutter release used (set at 30 second exposure times). The camera was mounted on a top dovetail plate on my “new” Celestron C11 SCT, mounted on a Losmandy G-11 Gemini mount, roughly polar aligned.

Multiple images were captured before, during, and after the flare’s visible streak peaked. This image is a combination of just the two consecutive images that contained flare data. The two images were then combined with Image Stacker using the brighten mode. Image processing – PhotoShop CS was used only to adjust the midpoint (gray level) to reduce the red cast of the background sky. Very slight unsharp masking was done before saving the image as a .tif file and importing it into Neat Image for some noise reduction. The image was then saved and re-imported into PhotoShop to crop to 4x6 before adding the frame and text.

Comments, questions and critiques welcome. :)

Paul

Subra
2007-Jun-28, 12:05 AM
Nice picture. I don't quite have the camera equipment for that, I fear.

I'm guessing you knew this was coming, and didn't just randomly expose your camera at the sky. Where can I get orbital elements for these satellites?

andyschlei
2007-Jun-28, 12:52 AM
Nice picture. I don't quite have the camera equipment for that, I fear.

I'm guessing you knew this was coming, and didn't just randomly expose your camera at the sky. Where can I get orbital elements for these satellites?

It's a great picture!

You can get all kinds of satellite information at Heavens-Above.com (http://heavens-above.com/)

Subra
2007-Jun-28, 12:56 AM
It's a great picture!

You can get all kinds of satellite information at Heavens-Above.com (http://heavens-above.com/)

Well ain't that the coolest thing? Thanks!

For low-earth satellites, I guess being off by a few km might matter, would it? Their database doesn't have my town, but it has the next town over. I guess I could get a map and do some interpolation too.

andyschlei
2007-Jun-28, 01:22 AM
Well ain't that the coolest thing? Thanks!

For low-earth satellites, I guess being off by a few km might matter, would it? Their database doesn't have my town, but it has the next town over. I guess I could get a map and do some interpolation too.

What I have done for non-cataloged locations is to find the location in Google maps, and then look at the link provided in "Link to this page." The link has the latitude and longitude in URL, after &sll=

You could also try other mapping services like the Tiger Mapping service (http://tiger.census.gov/cgi-bin/mapbrowse-tbl/) from the census bureau.

AutoClub
2007-Jun-28, 01:55 AM
Thank you, Subra and andyschlei!

Subra, what I did to find my exact coordinates for my backyard/residence was to first go to www.multimap.com - I plugged in my home address and when it brought up the map for my neighborhood, at the bottom of the screen, below the map on the right side, it gave me the exact coordinates when I am located.

Then I went into www.heavens-above.com and told it I wanted to add a location, manually, and I entered the coordinates that I had received from Multimap. I called it "My Home" for easy reference. I then set that location as my default in Heavens-Above. So now when I want satellite info, it gives it to me based on where I am located. It's so cool! :)

I have used Multimap.com for numerous locations where I plan to set up for observing, or if I'm going on a trip somewhere and plan to observe with my equipment. For example, I've been to a few different schools here in Southern California for their "Science Night", and have helped other members in my local astronomy club by providing a telescope or two for the students/parents/staff/public to look through. It helps me when setting up my Losmandy G-11 - I just plug in the "new" coordinates for where I am observing from that evening, and the mount then knows where I am located. It helps a lot when it then goes to the first alignment star - at least it’s usually in the field of view or close to it, thus saving a little time in aligning the scope. Plus, one of the neat things about being able to plug in pertinent data on the Heavens-Above website is the ability to get satellite information and their "whole sky chart" for any particular day you want. It's kind of neat to be able to see when there's going to be an occultation, etc. I use their "Daily Predictions for brighter satellites" (usually Magnitude 3.5 or 4.0 is sufficient for my light-polluted area)) :( and by clicking on the time under the "Max. Altitude" column, it gives me the visible pass details, and the whole sky chart showing me the path of the object of interest. I have found it to be of great value, a lot of fun, and very accurate.

I was watching the ISS the other night after looking up the info on Heavens-Above. I watched it pass on the South side of the Moon - really cool through binoculars! I then went back into the house, and looked up other things to check that night, and found the HST was going across the Moon. I had hoped to get a sighting on this as well, but wasn't sure how accurate it would be. From my location, the HST went directly across the Moon, almost right through the middle of it. Too bad I didn't have time to set up a tripod and image this. Not sure how well the exposure would have captured it, though. The Moon was past Quarter and very bright, but with binoculars, the HST was very visible. The neat thing is that once the HST had passed the Terminator on the Moon, it became visible again. Man, that thing is clipping!

Subra, I don't know what kind of camera you have, but if you have a decent tripod that's sturdy, and a camera that you can take (hopefully) multiple pictures in rapid succession, and that has the ability to take probably 15 second or longer exposures, and an ISO setting of probably 400 or faster, I would think you should be able to capture at least the brighter flares. It would help if you also have the ability to use a cable release, or remote shutter cable, so you do not introduce extra vibrations into the image by pushing the shutter by hand. If your camera is an SLR-type that has a mirror that moves out of the way before the shutter is opened, the ability to "lock up" the mirror moments before the shutter is actually opened will provide additional damping of camera vibrations. Mirror lock up is probably not as important for wide-angle shots as it is for longer or telephoto shots, and longer exposure images from my experience are not troubled as much as very short exposures if this is not available.

Thanks to both of you for your comments! :)

Clear skies!

Paul

JAICOA
2007-Jun-29, 10:44 PM
Great shot! Welldone Paul

stktos
2007-Jul-02, 12:48 AM
great job, very neat

paul f. campbell
2007-Jul-03, 12:41 AM
Hi Paul.

Nice work as always. What I really like is your NEW set up. Cant wait to see what this scope has to show us, way cool. later Paul