Oct 042015
 

Sun in H-alpha

This is my first successful image of the sun, taken through my new Coronado Personal Solar Telescope (PST). The PST uses a Hydrogen Alpha filter to block out all wavelengths except a narrow 0.5 Angstrom band (the spectrum of visible light ranges from 4,000 to 7,000 Angstroms). One advantage of using such a narrow bandwidth is that glowing hydrogen gas that moves toward us or away from us can be seen as a slight darkening or brightening relative to the background. For example, solar prominences are plumes of hydrogen that erupt from the surface of the sun. Seen edge on, they appear as dark ridges because the wavelength of light they emit is reduced slightly and consequently blocked by the H-alpha filter.

In this image, you can see dark “cracks” on the face of the sun that are actually prominences viewed edge-on. Prominences can also be seen on the limb (the edge of the sun’s disk) as red bumps on the right-had side of this image.

This image is not the result of a single snapshot, but rather the sum of over 1200 frames taken from a 2-minute video taken at 30 frames per second on October 1, 2015. Software is used to analyze the quality of each one of 3600 frames (120s X 30 fps = 3600), sort them by quality, then align and add together the best third and discard the rest.

Camera used was the Canon 6D shooting at 1/30th sec, ISO 6400 for 120 seconds. I then used PIPP (Planetary Imaging PreProcessor) to open the source .MOV file and AutoStakkert!2 to align, combine and sharpen the images. Original video was shot in monochrome. Red color to approximate what our eye sees when it views a Hydrogen Alpha source was added to the final result.

Compare the image above with a single frame of the video below. Note the vastly improved quality that results from aligning and combining hundreds of individual frames.

Single frame from video sequence, 1/30th sec exposure, ISO 6400.

Single frame from video sequence, 1/30th sec exposure, ISO 6400.

Jun 062012
 

A Transit of Venus (Venus passing across the face of the sun) is a rare event. This alignment of Venus directly between the Earth and the Sun will not occur again until the year 2117, when I am 169 years old. So I really wanted to see this one. Cynthia and I had planned to drive to Eastern Washington if the sky conditions there looked more favorable. But on the contrary, on Tuesday morning the forecast for East of the mountains looked worse than for here (cloudy to mostly cloudy). So we decided to stay on Whidbey and take our chances.

It was raining here early Tuesday afternoon, June 5 and the sky was overcast. The Venus transit was to begin at 3:06 pm. But this ever-optimistic astronomer went out to turn on his equipment in the observatory and set up the “sun funnel” he built for this occasion.

Friend Sue and second cousin Emily showed up full of hope, believing that anything is possible: for all we knew, we could get lucky and the sky could clear just in time. We couldn’t open the observatory dome right away, but by 2:30, the rain had turned to a light mist so we opened the dome.

Telescope at the Tinyblue Observatory

Takahashi 4" refractor telescope mounted on Paramount ME mount with sun funnel

sun funnel

This "sun funnel" is attached to the telescope eyepiece.

It was too cloudy during First Contact (when Venus first appears to touch the disk of the sun) and Second Contact (when Venus is completely inside the disk). But about 45 minutes after the transit started, the clouds thinned out a bit. We never had a clear sky, but the clouds were thin enough that we could see an image of Venus, along with a few sunspots and clouds drifting by.

Image of Venus crossing the face of the sun

Venus crossing the face of the sun

Transit of Venus

Transit of Venus about an hour after first contact

Cynthia viewing the transit of Venus

Cynthia viewing the transit of Venus

Be sure to take a look at the movies taken by the Solar Dynamics Observatory, which is an earth satellite in a geosynchronous orbit at an altitude of 22,000 miles.

So thank you, Sue and Emily and Cynthia for your optimism. I’m glad I don’t need to wait until I’m 169 to see my first transit of Venus.