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ISS Lunar Transit (2018Feb01)

ISS Transit on Feb 1, 2018 ISS Transit on Feb 1, 2018 ©2018 Frederick Steiling
Image Links
Full resolution
Via Youtube
Target Information
Main Target Designation(s) ISS Transit of the Moon, 97.2% Illuminated Moon
Date(s) of acquisition 01Feb2018 (Transit at 22:13:34 CST)
Location Sunset Hills, MO
ISS Information
Angular Size 44.50″
Distance 620.99 km
Angular Velocity 29.5 ′/s
Transverse Velocity 5.32 km/s
Radial Velocity 5.12 km/s
Total Velocity 7.38 km/s
Transit Acquisition
One-shot Color Video 1080p Video at 29.97fps
ISS extraction 23 frames
Manual mode config 1/4000s exposure at ISO200
Capture resolution 1920x1080
Lunar Disc Acquisition
One-shot Color Exposures 30 of 614 frames stacked
Manual mode config 1/8000s exposure at ISO500
Capture resolution 4608x3456
Imager Olympus E-P5 (prime focus)
Telescope/Lens Orion 8" f/3.9 Astrograph
Focal Length 800mm (f/3.9)
Mount Celestron CGEM
Focuser Moonlite 2" Reflector Format
Focusing Moonlite V2 Controller
Acquisition FireCapture 2.5
Guiding None
Processing PIPP v2.5.9, AutoStakkert 3, Registax 6, PixInsight 1.8, Photoshop CC

In a fleeting moment, one could miss this curious celestial event, and that if you even knew it was coming!  Thanks to the handy Transit Finder, I was made aware of a lunar transit of the ISS very near my home location.  Though the ISS passed overhead in the shadow of earth, it made a quick cloaked appearance across a nearly-full lunar disc.  You can't blink -- and the camera can't quit -- for an event like this.  From where I sat (only about a mile from the center line in Sunset Hills, MO), the off-center transit at this location lasted a whopping three-quarters of a second -- only good for 23 frames in a standard 30Hz video as seen in the raw capture I posted of this event (via YouTube)!  In the composite above, we see the solar panels flanking the center service system of these 23 frames overlayed on the evening's moon captured just prior to the transit.  It's a fascinating look for many seeing it for the first time, as it may not be immediately considered that the ISS doesn't travel in an orientation square to its path of travel.

This was first time imaging the ISS from a telescope.  Some lessons learned are that the video capture on the E-P5, though necessary to provide the best opportunity at capturing the transit, results in some quite compressed frames extracted to composite.  A more appropriate large-format planetary camera would no doubt provide better resolution for this type of event, but I'm pleased of the outline detail of the ISS shape, albeit a bit fuzzy.  (Hey, that's why we call this Fuzzy Photos anyway!)

I look forward to trying the ISS again and honing in my acquisition technique.  For now, though, we can sit in awe of the ISS' sneaky appearance overhead.

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