Central Texas is hot; maybe your location is too. Today, the high here was 103F, and I was outside in it taking these pictures of the sun. The solar scope is in direct sun, of course. My observing position is under the boughs of a nearby white oak – partial sun at worst. Still, it’s an oven out there.
Toys and Instruments
All of my audio-video and optical instruments are also toys. That is, upon their acquisition, I have to use them in order to satisfy the Y-chromosomal urge to tinker and discover. Read the manual? Who, me? Nay! Tinker and discover!
I’ve had a good two weeks of actual solar imaging toy tinkering, and it has been excellent fun. Now, it is getting time to read the manual and undertake a more disciplined and studied exploration of the instruments that were just yesterday wonderful toys.
Today, I systematically examined the image resolution, A/D image conversion, and exposure issues of the ASI183 color camera that is attached to the solar scope. Working in the toy phase, I had been using the second highest camera resolution and auto-exposure settings simply because they gave me a nice image with minimal fuss. Today, I tried the highest resolution (it’s a 20MP color camera) and manually set the exposure setting to 4-msec which seemed to provide a good image when the auto setting gave only an over-exposed blob. I also kicked up the A/D converter to use 16-bit RAW rather than 8-bit RAW encoding. That gives me a 65K color palette rather than only 256 colors. I manually tweaked the four focusing devices in order to optimize the image.
Below is the result of a stack of about 100 images.
The increase in color depth as well as the increase in resolution yield an appreciably better image albeit at the cost of a larger image size. There is no free lunch.
Below are cropped images that emphasize the largest group of sunspots and surrounding plage on the disk’s western edge, and the prominences from the upper eastern limb and the southern limb.
