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HT and thanks/Willie Soon
Hinode’s close call with Santa?
Based on a highly accurate back of the envelope calculation, Santa is larger than the planet Earth. Quelle surprise!
sun & sound
Thanks, and Merry Christmas, Happy Holidays, and/or whatever else is appropriate and non-offensive to you.
Have a radiantly happy day!
The energy range of X-ray photons detected in solar X-ray imaging is 2-80 keV, according to Skyandtelescope:
Does anyone know if this solar X-ray imaging is done using a optically scintillator-coupled ccd, or a flat panel (Cmos) camera? These are the two most commonly used X-ray cameras for laboratory systems over this photon energy range.
CCD based X-ray cameras have the better spatial resolution and good sensitivity up to about 30-40 keV. But flat panels have a thicker scintillator and wider energy window, and are better for photons from 30-80 keV.
NASA’s HDO carries two Extreme UV Variability Experiment instruments (collectively called: EVE) instruments that collect data in the soft X-Ray spectrum:
Different, complementary technologies.
MEGS-SAM employs a pinhole camera used with MEGS-A CCD to measure individual X-ray photons in the 0.1 nm to 7 nm range.
ESP uses 9 Si photodiodes behind a transmission grating, with 4, 5, 6, 7 diodes in the soft X-Ray spectrum 0.1-5.9 nm bandpass.
NOAA’s newest GOES-R (GOES-16/17) has 1 instrument for soft X-Ray data collection,the Extreme Ultraviolet and X-ray Irradiance Sensors (EXIS).
Thanks. I guess that flux is no problem so a pin-hole makes sense. Also I presume those X-ray detectors are energy-discriminating?
Occasionally when I get bored I go on google earth and look for interesting features far away from any human habitations or at the ocean floor.
Recently I got puzzled by this one
Easy to find with the location’s (coincidentally) square coordinates. The outer circle is 7 miles diameter, while the inner circle is 5 miles, no significant elevation difference, so may not be of volcanic origin. Geologically appears to be created ‘recently’and doesn’t appear to be man made since the nearest 2 roads are at 400 and 380 miles away.
Could any passing geologist explain? Unless there is an obvious explanation, I would favour a ‘Tunguska’ type meteorite atmospheric explosion.
To judge from the other circular features nearby indicating vulcanism, a heavily eroded volcano.
The lakes are also striking…
Also there could be, slightly off centre, an innermost circle with a two mile diameter.
Wikipedia says it is an impact crater, much eroded, less than 345 m.y. old, and that there are others nearby –
Space shuttle has looked at it
Thanks, Wiki’s article radar photo shows clearly the innermost circle.