GMT6 8.4m Casting

GMT6 8.4m Mirror Casting Web Index

Latest Oven Temperature Plots
(These plots of temperature versus time are what the oven pilot watches.
They update about every 4 minutes, and will continue into early June 2021.
Click on the individual plots for a fullsize version.
Click here for plots cycling one-by-one each minute with size matching browser.)
Historical High Temperature Plots
(These historical plots of the high temperature phase of 8 different mirrors help us verify the recipe.)
Before & After Flash Video Images
(Compare as the blocks of E6 borosilicate glass soften, merge, and flow down into the honeycomb mold.)
Latest Flash Video Images
(Click on the individual images for a fullsize version.
The pages of plots and images have optional auto refresh timers - 20 sec minimum.)
Latest Flash Video Images as a Slideshow
(We have 6 digital video cameras that look at the hot glass inside the furnace through small holes.
They take flash images in blue light for contrast against the blackbody radiation every 6 minutes or so.)
Timelapse Movie of Glass Melting
(This time lapse movie of each camera in sequence is assembled by G. Gasson.
It shows the motion of the softening glass sped up by a factor of approximately 5000.
This is a 129 MB MP4 file from 10pm on March 6, and it has stopped updating.)

Approximate schedule of glass softening:

Friday, March 5, 2021
  15:00 MST  Furnace starts turning  (750 C)
  16:00 MST  Furnace rotating at 4.8 RPM (762 C)
  19:00 MST  Noticeable glass softening (810 C)
  21:30 MST  Glass blocks slumping (850 C)
Saturday, March 6, 2021
  00:50 MST  Glass melting        (900 C)
  05:40 MST  Smoothing of glass surface (980 C)
  10:30 MST  Glass clear          (1070 C)
  14:10 MST  Maximum Temeperature (1165 C)
  18:10 MST  Start cooling        (1165 C)

Spinning furnace during previous GMT5 casting
(20171106 photo by Alessandro Cavallaro)

YouTube video about preparing for the GMT6 casting (3 minutes)
YouTube video from Zoom event on Saturday March 6 (1.5 hours)
phys.org 06-Mar-2021 by GMTO Corporation:
Engineering Marvel: Sixth mirror cast for Giant Magellan Telescope (w/ mold assembly timelapse)
spie.org 01-May-2020 by William G. Schultz:
Casting Giants: spun-cast telescope mirrors continue to shape astronomy's future
Richard F. Caris Mirror Lab public web page
Giant Magellan Telescope public web page
Steward Observatory (UArizona Dept of Astronomy) public web page