This is a website of my voyage into photographing the night sky (hence the domain SeeingAfterDark.com). For those who are thinking of discovering the evening sky with their own camera, I will display some of the very first images I captured along with my best. This way you may better realize that with a bit of perseverance, truly beautiful images can be captured, even with a very modest budget.
M51 Supernova, 6-4-2011
16 x 60 secs, Canon 550D, iso 3200
|Speed reduced by a factor of 3
The International Space Station can be often seen passing overhead, generally as a bright golden yellow "star" moving relatively fast in the sky (In general, it will move across the sky in less than 5 minutes). There are a number of websites that will predict where & when the ISS will pass overhead based your location, notably www.heavens-above.com .
Occasionally, the ISS will pass near well known stars, planets, and even the Sun and Moon. Friday night 8-20-10, the ISS was predicted to pass in front of the Moon in Southern New Jersey. It was an "invisible" pass, meaning the ISS was in Earth's shadow and could not be seen in the evening sky, BUT would be silhouetted as it passed in front of the moon. A number of factors make witnessing this event not "easy".
At a distance of over 700 Km, the ISS is approximately
70 times smaller than the Moon, so it can't be seen with the naked eye.
High power binoculars or telescopes are needed.
Timing is crucial!! At a ground speed of over 18,000 mph, the ISS whizzes past the Moon in about 1 second. If you blink at the wrong time, you could almost miss it.
Just like an eclipse of the Sun, you need to be in the right location to observe this event, within a radius of about 8.5 km of it's predicted transit.
New Jersey has an average cloud cover of 60%, so chances are better than even the Moon would be covered over just as the transit occurred.
Fortunately, skies were predicted to be clear , so two intrepid groups from the Willingboro Astronomical Society met on Friday nightto witness this Lunar ISS Transit, one group meeting near Dellete, NJ and the other group (which I was a part of) met in Winslow, NJ.
I recently purchased an XT10G telescope from Orion Telescopes in Ca, a new class of telescopes just coming out for the public (suggested to me by Lloyd Black, our current WAS President). This is a medium/large size Dobsonian telescope, with a 10" diameter mirror, and a twist... it is a computer controlled Dobsonian, with GOTO and auto-tracking, a feature not common in most Dobs.
This is going to be my first time imaging with this scope. Understanding the optics of my scope, I know that my webcam has a small sensor (1/4" diagonal) so I could only image about 10% of the moon's surface. I also have 4 different size "focal reducers" (ranging from 0.8x to 0.33x), which essentially reduces the magnification and would allow me to image up to 15-70% of the moon's surface with each shot. Of course, none of them worked on my new scope. Fortunately, Alan Darroff, who knows so much more about the Solar Systems and lunar details than I do, helped me negotiate the lunar features and orient my scope so I would have the greatest change of capturing the ISS transit.
From previous experience of capturing a Solar ISS Transit, I knew the ISS is moving so fast that the image easily blurs. So, I set the brightness and gain way up, allowing me to set the shutter speed to 1/1500 sec. I checked all my settings... video is set for two minutes of capture; video file is being saved to the disk that has plenty of free space (made that mistake once before); frame rate is being captured at 30 frames/sec; Focus looks good; Put the laptop in sleep mode to conserve battery power (also made that mistake before). Now just wait.
Time for the transit is approaching. Drew Maser brought his shortwave radio, announcing the reference time. Steve Mattan showed me a new App for my iPhone that displays a standard reference time to hundredths of a second. I do a final focus check and begin capturing at about 1 minute before the predicted transit time of 10:26:45 PM. While watching the screen I hear, "Is it time yet? is it time?", being called out by other members. Then at 1 minute 10 seconds after I began capturing, I see a "black thing" zip by on my laptop screen and shout out, "GOT IT!!" Others in our group indicated they saw or captured it, some others think they got an image, but need to look closely to confirm. I open my folder and see the file is saved (Whew!!) I first make a copy of the video, so if the computer crashes while I view it, my original is still intact (made that mistake before, too). I open the copy, and at 1minute, 10 seconds after I began capturing, I see the ISS fly by again. Success!! I pause and can see relatively sharp images in individual frames.
I captured a total of 12 frames with the ISS (10 full images, 2 partials). The images were captured at a relatively high magnification, about 200x.
|Composite Image of ISS Lunar Transit
*Lunar surface was stacked in registax... 200 of 2347 images
(first removed the 12 frames that contained the ISS images)
* Extracted the 12 frames containg ISS using virtualdb
*Used "magic wand" in PS to isolate ISS and then applied unsharp mask
* Scope - Orion xt10g in autotracking mode (1200 fl)
* Camera - Philips Spc900NC webcam * 30 frames/sec
* Shutter speed - 1/1500
* Magnification - approximately 200x (webcam is equivalent to about a 6mm EP)
A successful evening with a great group of guys:
Jim Mack captured about 16 frames across the entire moon's surface with his DSLR and 12" Meade at a lower magnification (the focal reducers work on his scope).
Steve Mattan got what he called his first "successful" ISS capture.
And, as always, Jerry Lodriguss captured a magnificent image.