NASA kindly e-mailed us to notify of an ISS passage over our back garden so I decided to “have a go” with the Tak Mewlon 180 F12 and ASI 120MM CCD camera at prime focus (2160mm).
I used a heavy duty photo tripod and a binocular alt-az fork mount and tried to follow the ISS in the finder scope. The ASI 120MM ccd is 1280x960 pixels fiving a FOV of approx. 6x4 arcmin, so I wasn’t expecting great results. From the 8126 frame AVI (over 9 GB) I manually found a handful of frames with the ISS in the FOV, the remaining 8100 were empty!
Here are two of the better frames; no stacking was possible so these are just single frames.
Tak Mewlon 180 F12
ZWO ASI120MM CCD camera 1280x960
˝ millisecond exposure.
I was in my back yard last night with my Scope .....glanced up and saw this ' bright ' moving object travelling overhead ( roughly the same time Dennis saw it ).....watched it for about 2 minutes....ISS I thought....must be.....never seen a ' satellite ' that bright.
Quite enjoyed the occasion watching it.
Flash......
Last edited by FlashDrive; 29-09-2013 at 01:32 PM.
Great capture Dennis! My question is how did you pick an exposure to suit?
We were in town waiting for Riverfire. There was a newspaper article mentioning the IIS would be visible in the lead up to the show, so I looked up heavens above and worked out where to look. It arrived, bang on cue.
The jets were incredible during their daylight passes. They were banking from side to side along the city reach of the river, and then pulling up sharply to avoid the apartment buildings beside the Story Bridge. They appear to be much more manoeuvrable than the old F1-11s, but not as loud or spectacular without the dump and burn...
Thanks Laurie, Morton, Col and David for your comments, I appreciate them.
@David: I was fortunate enough that the brilliant Venus was visible in the falling dusk light so I was able to focus reasonably well on the planet’s disc although manually pushing the mount/scope combo whist eyeballing the computer screen and tweaking the focus knob could have done with 3 pair of hands, not just the one!
I just guessed the exposure (first time doing this) and using Firecapture, set it to 0.5 milli-seconds and just hoped for the best based on what Venus looked like on the display.
I think that for this particular pass, I was in the ball park as on a couple of the frames, specular highlights are completely blown out.
It went over Sydney too. I was outside showing SWMBO Venus+Saturn+Mercury when I unexpectedly spotted a bright satellite - we followed it almost from horizon to horizon.
I must keep a better watch for ISS passes. When I went inside and checked Satellite Safari and CdC had predicted the ISS would be mag about -2.1.
Thanks guys; I just downloaded the data sheet for the Aptina MT9M034 ccd chip which I understand is the one used by ZWO for the ASI120MM camera.
The chip dimensions are 3.54mm x 2.69mm and if I had known this before the ISS passage, I probably would not have attempted to arm wrestle a 2160mm focal length telescope with the hope that a few photons may serendipitously land on the chip!
Thanks for all your nice comments, I appreciate them.
The AVI came out to over 9GB and all my traditional AVI applications did not recognise it so I used VirtualDub to “repair” the file (an error message about not being able to find keyframes) and then just scrubbed through the 8126 frames using the Slider in VDub to select those few lucky frames where the ISS appeared.
I have never played a computer game in my life so maybe I’ll practice on aeroplanes in daylight next time!
Cheers
Dennis
@John – love the “is sprinting astroimaging” comment – excellent pithy humour!
Top effort Dennis, reckon if you put your mind to it wont be long before you image an astronaut on a tether performing maintenance outside the Space Station.
Great work Dennis. Excellent detail showing and that must be good given the wrangling needed to capture a couple of sharp frames. Must be a bit like the scene in Apollo 13 where Lovell and Haise are trying to keep the earth in the field of view during a burn without the computer.
