Saturday, September 2, 2017

Total Solar Eclipse of 2017 - Part III

Part III - The Technical Details

My Equipment

Basically my eclipse equipment doubles as my astrophotography gear.  That included my 8" Celestron SCT and a Celestron 500mm Mak lens piggy-backed on the telescope. I used two Canon cameras: my new EOS 6D was mounted on the C8 and my older EOS 50D was on the 500mm.

Primary Equipment

  • Celestron Celestar8 Deluxe Schmidt-Cassegrain (Schmidt-Cass or SCT) reflector telescope 
    • standard "Wedgpod" (wedge and tripod)
    • custom aluminum and 3D printed "piggy back" rail w/ Manfrotto quick-release adapter (I designed this adaptor and feature it on Thingiverse: C8 Camera Mount Assembly
    • Thousand Oaks Optical white light, silver/black polymer solar filter (RG-9187)
    • Celestron Reducer / Corrector f/6.3 (model #94175)
    • Orion T-Adapter (#5116)
    • TalentCell 12V/9V/5V 8.3Ah Power Bank w/5.5x2.1mm power cable (model YB1208300-USB)
  • Canon EOS 6D full-frame DSLR
    • Opteka intervalometer w/ Kirkland AAA batteries 
    • Canon LP-E6 and Powerextra batteries 
    • SanDisk Extreme PRO 32GB SD cards
  • Celestron 500mm f/5.6 Mirror Lens - Maksutov-Cassegrain (Mak or MCT) Spotting Scope 
    • Thousand Oaks Optical white light, type 2+ glass solar filter (S-4250 I believe)
    • Manfrotto 200PL quick-release plate
  • Canon EOS 50D crop (1.6x) DSLR
    • Zeikos battery grip (ZE-CBG50)
    • Neewer intervalometer (EZa-C3) w/ Kirkland AAA batteries 
    • STK BP-511A batteries 
    • SanDisk Extreme 8GB CF cards

Secondary Equipment

  • Canon FS100 digital video camera
    • XX tripod
  • GoPro Hero (original) action camera
    • custom 3D printed base (and duct tape)
  • Garmin Virb X action camera
    • Manfrotto 200PL quick-release plate and adaptor
    • Manfrotto ball head
    • Manfrotto tripod
  • Samsung Galazy S4mini Duos

Miscellaneous Stuff for the Event

  • Garmin "Colorado" 400t GPS
  • Sperti Inc, Astro Compass Mark II (WWII vintage)
  • green lasers for pointing to starts, planets, constellations, satellites, etc at night
  • Pin-hole viewing "equipment"
    • retasked lens aperture and telescope end-cup for an adjustable pin-hole
    • black foam board and aluminum foil pin-hole 'slides'
      • fingers, hats, etc work too
    • white foam board for a 'screen'
    • camp chair to rest the screen on
  • A few 4/5" x 5.5"shade #14 welding glass
  • miscellaneous "eclipse" glasses including sets from the WyoParksEclipse (came with the parks passes I purchased) and some older "Eclipser" glasses from the Venus transit
  • mason's line for setting-up / checking North alignment
  • folding table
  • scrap carpet remnant for placing more delicate equipment on the table (and keeping it from rolling / sliding around)
  • Walmart 'easy-up' sun shade (kept me from getting sunburn when not in totality)
  • camp chairs

Settings

The camera's were set with the following notable exposure values...

Canon EOS 6D (t-mount on C8 w/ reducer)
  • effective focal length 1280mm
    • 'un-reduced' focal length is 2032mm
  • fixed aperture f/6.3
    • 'un-reduced' aperture is f/10
  • Custom 1 (partial phase):
    • "M" mode
    • ISO 100
    • Tv 1/800s
    • no bracket
    • Remote timer settings: 
      • 1min interval
      • N=81
  • Custom 2 (totality):
    • "M" mode
    • ISO 400
    • Tv 1/30s
    • +/-2stops, +/-4stops bracket (5 shots)
      • +/-2stops = 1/8s, 1/125s
      • +/-4stops = 0.5s, 1/500s
    • Remote timer setting (planned): 
      • 1/2s interval
      • N=272
Canon EOS 50D (piggy-back on C8 w/ 500mm lens)
  • focal length 500mm
  • fixed aperture f/5.6
  • Custom 1 (partial phase):
    • "M" mode
    • ISO 100
    • Tv 1/200s
    • +/-1stop bracket
      • +/-1stops = 1/100s, 1/400s
    • Remote timer setting:
      • 1min interval
      • N=81
  • Custom 2 (totality):
    • "M" mode
    • ISO 400
    • Tv 1/8s
    • +/-2stops
      • +/-2stops = 0.5s, 1/30s
    • Remote timer setting (planned):
      • 1s interval
      • N=136
50D under-exposed at 1/400s
These exposure settings were based on Fred Espenak's exposure guide: MrEclipse.com SEphoto.html and the results of a few test shots.
For example, the 50D on the 500mm was test-shot at ISO 100, using shutter times of Tv = 1/1000s, 1/800s, 1/640s, 1/400s, even 1/25s, finally settling on a bracket at 1/200s.

Similar testing was done for the 6D on the C8, shooting at ISO 100, using shutter times of Tv = 1/400s, 1/500s, 1/640s, 1/800s, and 1/1000s.  For the 6D/telescope setup I settled on 1/800s as the best exposure.

Lessons Learned

Practice, practice, practice!  OK, that was the advice of the Canon site, and a number of others that I visited pre-eclipse. The problem was, I did not follow it very well and when it came to totality, I was mesmerized.  My biggest mistake: I did not switch my camera customs settings from C1 to C2.  All told, photos came out OK anyways and I witnessed an amazing event.

What would I change for next time:
  • Spend more time on focusing the telescopes - I had tools at my disposal that I did not use.  I brought along a laptop to view the test shots--did not pull that out.  I had a Bahtinov focus mask I could have used--but didn't.  I could have done more with the "live view" and a magnifier, but didn't.
  • Adjust the orientation of the 50D - I had the Moon traveling across the Sun from bottom of frame to top of frame.  This was mostly old habit because the camera orients better when mounted piggy-back on the C8.  However, the solar corona tends to be "wider" in the solar plane or ecliptic.  Because of this, I would have captured more corona if the camera was oriented 90deg or "landscape" mode.
  • Change the exposure settings for totality - as already noted, I had planned to do just that, but the emotion of the moment apparently got in the way.
  • Don't forget the other science - I had planned to bring my hand-held weather station, but forgot.  I considered trying to video record the shadow bands, but figured I had enough going on. 
  • Try wide-angle shots of the eclipse - it is very common to see wide-angel stacked photos (multi exposure pictures) with a visually appealing foreground and the eclipsing Sun / Moon in the sky.  Equipment limitations were my primary reason for not trying this--I already had two DSLRs and three (four) video cameras going.
  • Try making video of totality (magnified shot of the Sun/Moon) - again, equipment limitations were my reason for not trying this.
  • Bring my ham equipment - one of the guys I met on the hill (from TX) was a ham and he had been following the NASA balloon experiments.  I should have thought of that!
  • See if there are other phenomenon that can be mixed with the event - A great example is that one of my long-time buddies who is also a photographer (much closer to pro than me), captured the ISS transitioning the eclipse (BlairCraft Photograpy)!  Blind luck, considering the whole transition took less than a second, but he caught it.

Next Chance

With all the reading, videos, etc that I followed leading up to this event, I heard a similar mantra repeated by folks who had already experienced totality: it is addicting.  I have to say, I now understand.  The event went too quickly and I want to experience it again.  Is that a consequence of today's high-tech society were repeated videos are just a click away; where you can find literally thousands of photos, from different angles, times, colors, ... of the same shot?  Maybe.  

This was an experience.

Now, just like back in 2014--prior to the total lunar eclipse--I am looking forward to 2024 in Texas.

Thank you for visiting my blog!

Just a little plug for my equipment:
#Canon #EOS #CanonEOS #6D #50D #Celestron #Garmin #virb


As with the original Star Wars trilogy, the best part of the story starts with a later episode.  I have captured this total eclipse adventure in a number of postings for my own recollection--and you are more than welcome to visit the other pages...
Part III - The Technical Details


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