Solar Eclipse Expedition

Heading Down for the Event

The day finally arrived, and it was time to head down south for the 2017 solar eclipse. Ed, Sydney and I all headed out around 8:30 a.m. on Sunday, August 20. The trip down was uneventful. We took state highways the entire way, in order to avoid any traffic buildup. We hit the Ohio River at Cave-in-Rock, IL around 4:30p.m. The trip was very boring (notwithstanding a little relief in the terrain down in Shawnee National Forest), so we took a quick side trip to Cave-in-Rock State park to see the cave. Back to it, and we touched down at my aunt's house around 6:30 p.m. We ended up going out to grab BBQ at Knoth's by the Kentucky Dam. It really is a crime to visit western Kentucky and not get BBQ.

The next morning, we got up, had breakfast, and headed over to another aunt's house for the event.

Setup

Setup took a good hour and a half. Using the coordinates obtained from Google Earth for the location, I was able to look up the location of the Sun during the event from where I would be positioned using the NOAA's Solar Position Calculator (azimuth = 161 deg., declination = 63.6 deg.) With this knowledge, I could line up the tripod to ensure the sun shield was correctly oriented. (This is visible in the image of the equipment that was taken very near totality: the shadows of the tripod legs show that it is lined up very well with the direction of the sun.)

My primary photography setup. Note the shorter rear leg on the tripod. I needed to tilt the entire apparatus back to ensure I could get the angle to the sun, and not drive the camera into the telescope's base.

I tried using the cameras on cell phones for other photography types, but the time-lapse on one stopped after a few minutes (the phone overheated), and the other phone, using the 12x zoom just didn't do a good job of capturing a clean image. So, most effort was placed on the Sony/Meade telescope setup.

The Equipment, and Preparation

This consisted of a Sony a3000 20 MP camera with a T2 adapter connecting into the Meade telescope adapter. I used the shorter ring along to try and reduce the size of the image on the sensor (hoping to get more of the corona). This attached to the back of the telescope. While sighting in, I attempted to start working on the focus with the electric focuser (the original from Meade meant for this scope). For some reason, I could hear the motor spinning, but the focus in the scope just would not change. I opted to remove the electric focuser, and revert back to the manual method (ultimately, the better decision). On the tripod, I mounted my home-made sun shield, then draped the telescope in a white t-shirt. I added a black t-shirt around the opening in the shield to minimise the amount of ambient light around the camera's LCD. Finally, I added the home-made solar filter, and it was time to start focusing.

When I tried this in July, it was very difficult; partly due to the heat, most mostly, it's just a difficult process. So first, a bit of background. The Sony camera is fully automatic (although it does support manual modes). Without a lens, however, the camera's software has no way to determine if the image is in focus. The telescope is where the focusing takes place, and of course, no integration with the camera. So the process to get the focus correct consisted of the following:

1. Attempt to focus the image using the telecope's focusing knob while looking at the LCD.
2. When I think it's right, capture an image.
3. Turn off the camera, and remove the SD card.
4. Insert the SD card into my laptop (sitting about 50' away in the shade).
5. Open the image I just captured and zoom into something with fine detail (sun spots worked very well for this).
6. Determine if the image is in the best possible focus.
7. Eject the SD card (waiting for the OS to fully unmount it).
8. Insert the SD card back into the camera, turn the camera on.
9. If the image was in the best possible focus, stop, and don't touch the focus knob.
10. If the image was not in the best possible focus, return to step 1.

Back in July, I went through this process 6 or 7 times, and nothing came out really well. This time, I had it on the 4th attempt. Had I continued to use the electric focuser (if it were working), I would likely have continued to adjust the focus a small amount throughout the event, ending up with a sizable amount of images that were out of focus. Manually focusing forced the discipline to not play with the knob during the event, as it is very difficult to reach under the shield.

The Event

The rest of the event was spent shooting images, and watching in awe. When the sun was about halfway covered, you could feel that the sun was not as hot, There was no discernable difference in temperature between the shade, and out in the sunlight. It was also visibly darker. The darkness progressed very slowly at first. Within the last 10 - 15 seconds before totality, however, you could see the light diminish, as if someone was turning down a dimmer switch on a light. The sky turned a beatiful shade of blue - somewhat similar to twilight. As reported, day creatures became silent as the darkness progressed, and night insects became much more vocal. When totality hit, I tried to get a picture with my cell phone camera, but the auto exposure adjustment ended up overexposing the image, making the sun look full. The stars and planets became visible, as did the corona, which was magnificent. It also appeared like sunset on the horizon in all directions which was really interesting. I also forgot one piece to my tripod, which prevented the use of that for my cell phone camera. I did get a wonderful surprise as I snapped the images of totality, however. With the brightness of the sun blocked out, you could see solar flares shooting off the surface of the sun. I was able to capture them, and it ended up being a real treat.

By this time, the heat in the air felt the same no matter whether you were in the shade, or in the sunlight. You can see we got the bonus of some sunspots.

As we got close to the sun coming back out, I hopped back on the camera to try to grab the 'diamond ring' image. Unfortunately, the sun had shifted in the frame (as it had been doing, expectedly, all day), and when I tried to re-orient the telescope, it paused, and I held the button to move left a little too long. I then moved it back to the right and down a bit, then snapped the image of the diamond ring. Alas, it was too late, and the flare was really much larger than I intended it to be. At this point, I continued to shoot the progression from totality as I had when the event started. This gave me the ability to do the progression image below.

Notice the solar flares on the right, and lower right. Awesome bonus for the event. This image is shows that there wasn't much to see for the corona; though I could have increased the ISO and/or shutter speed, and captured more. That said, with this setup, the sun is sop large in the frame, I would not have been able to see much.

My 'diamond ring' image. You might say this has a really big rock.

As much fun as this was, photographing the entire event spanning a few hours was very hot work. The temperature was into the 90s, and when my aunt checked the weather, the heat index was 105 degrees. The period of totality, went by very fast however. As I think back, it felt like it lasted 20 seconds.

Progression through the event.

Lessons Learned

What Went Right

• Take more gear than you think you'll need.
• Make a checklist of everything you want to take.
• Practice, practice, practice. Most of the problems I had were averted because I ran into them over the summer leading up to the event.
• I ended up using a fisheye lens on the time-lapse device. This allowed capturing the tree line and the arc of the sun (even the wide-angle was not sufficient to get both).
• Share the event with friends and loved ones. This is one of those events that are so much more fun when shared, and I got to see it with my daughter which really made it much more special.

Opportunities for Improvement

• I had problems with the electric focuser during practice, and again during the event. I will definitely not trust that piece of equipment again.
• Snap more images. I used only about 1 Gb (on a 16Gb card). There was no reason I could not continue snapping away during totality.
• Try to get the diamond ring before and after totality - two chances to get the image, rather than one.
• Instead of having a solar filter that fits over the end of the telescope tube, I think a small apparatus that allows you to flip the screen in/out of place makes more sense. I dropped the filter when I removed it, and could have risked bad dust spots when I put it back in place.
• Start preparing earlier. I missed grabbing the full sun prior to the start of the event because I was still working on the focusing exercise.
• When trying to shoot a time lapse, make sure the device stays cool. A shield of some sort may have prevented the phone from shutting down early.
• A better camera would be a good bet. The a3000 isn't bad, but Nikons and Canons are better suited to astrophotography. Having something that is viewable from the computer screen would be really helpful, as I would not have to run back and forth during the focusing exercise.
• Locating on high ground would allow a better view of the horizon.
• It might be worth getting the tracking software working. Much of the time behind the camera was spent adjusting azimuth and declination to keep the camera in frame.

Other Interesting Notes

• This was viewed from Princeton, KY (37ᵒ 05' 28.6" N by 88ᵒ 01' 17.95W).
• Telescope properties: f-stop: 13.5, focal length: 1350mm.
• Temperature was in the low - mid 90s.

Parting Thoughts

I spent the day of the event with family. This was as important as the event itself. Aunt Jean provided accommodations while we were down there, and Aunt Barbara and Ron hosted the event (and threw together an amazing dinner of pot roast, potatoes & carrots, and cole slaw). With my dad and daughter participating also, it made for a really neat family event. To further illustrate the hospitality that you get down there, I give you the following. As the eclipse was proceeding, a man and his wife from Texas was driving slowly through the area. They had been locating the center line of totality on an app for their phone, and ended up on the street in front of the house. It seems they were chased away from another neighbor. We waved them over, offered them lunch, and had a nice visit with people we had never met. When you can share events like this with others, it makes for a sense of community, and and a much better story.