Testing for Solar Eclipse 2017, August 21 - Tellico Plains, Tennessee

"Whenever we want to watch an eclipse of the Sun 

we set out basins filled with oil or pitch, 

because the heavy liquid is not easily disturbed 

and so preserves the images it receives."

-- Seneca (Roman, 1st century AD)

There are some some photos which I did before solar eclipse, just for testing,  Canon 60Da,  Celestron Nexstar 4SE, Coronado SolarMax II 60.

Waiting Total Solar Eclipse 2017 - Celestron Nexstar 4SE Canon 60Da

Cloudy Sun - Celestron Nexstar 4SE Canon 60Da - Testing for Solar Eclipse 2017

H Alpha Sun - Coronado SolarMax II 60 Canon 60Da - Testing for Solar Eclipse 2017

Single Sunspot Astrophotography - Celestron 4SE Canon 60Da - Testing for Solar Eclipse 2017

Perfect Sun without Sunspots - Coronado SolarMax II 60 Canon 60Da - Testing for Solar Eclipse 2017 

Bahtinov Focus Mask - astrophotography Celestron 4SE

The Bahtinov mask is a device used to accurately focus astronomical telescopes. The Bahtinov mask consists of three separate grids, positioned in such a way that the grids produce three angled diffraction spikes at the focal plane of the instrument for each bright image element (star). Bahtinov Focus Mask, Celestron NexStar 4SE

Bahtinov Focus Mask, Celestron NexStar 4SE, Canon 40D, Spica Out of focus - the central spike is noticeably displaced from the

Bright star near perfect focus using Bahtinov Mask. Optimum focus is achieved when the middle spike is centered on the star and symmetrically positioned between the other two spikes. Small deviations from optimal focus are easily visible. Bahtinov mask, Celestron NexStar 4SE, Canon 40D