Monday, March 18, 2024

Countdown to April 8th: Sun Funnel Project

As I mentioned in my last post, I have a lot of irons in the fire for the April 8th 2024 total solar eclipse! One of those is all about viewing the overall eclipse: building a "Solar Funnel" or "Sun Funnel". 

Our old telescope,  a Parks 60mm refractor we bought about 30 years ago, happens to be on an equatorial mount and has a sidereal motor. All that means is that I can point it at something in the sky and the motor ensures that the object remains in the eyepiece (with only an occasional need to adjust the direction the telescope is aimed). 

Normally, we would never point a telescope at the Sun without a solar filter but in this case it is OK: we won't be looking directly into the eyepiece. Instead what would appear in the eyepiece is projected onto a piece of rear-projection screen material, allowing us to see it safely. Better yet, more than one person can watch at the same time!

We have used a similar approach in the past, projecting the Sun onto a white piece of poster board to check out sunspots but that was kind of cumbersome. This Sun Funnel design is much easier to use. 

Ironically, while the Sun Funnel does a great job of showing the solar disk including sunspots and the Moon taking a bigger and bigger "bite" out of the Sun during the partial phase of an eclipse, it won't be something we'll pay any attention to during the "Big Show"; it will be useless during totality since the Sun will have disappeared behind the Moon!

Still, the partial phase of the eclipse lasts hours compared to totality which only lasts minutes so the Sun Funnel will get a lot of use on the 8th. 

If you have a small telescope (even if it doesn't have a motorized mount) and you'd like to build your own Sun Funnel, they are pretty simple to make and don't cost much, either. One of the most commonly referenced sets of instructions is this one from American Astronomical Society, Nightwise.org and NASA:


It has full instructions on building it, how to use it and details like the calculations for how to determine the right size eyepiece for using a Sun Funnel on your telescope. 

I finished ours the other day but today was the first time the Sun was out long enough for me to test it. If you look closely at the second picture (click on it to see enlarged), you'll see that the bright circle in the middle is the Sun, pretty much filling the entire field of view. You'll also see a number of sunspots, several just above center and another one down at the bottom.

Whether you build your own Sun Funnel or not, I hope you will be someplace in the path of the eclipse on April 8th and wish us all "clear skies"!




Saturday, March 9, 2024

Countdown to the April 8th 2024 Total Solar Eclipse!

It's just a month away! Actually, as of the time of this post, the next total solar eclipse visible from North America is 30 days 10 hours and 43 minutes away!

Although we had to travel to see the Great American Eclipse in 2017 - the first and only total eclipse I have seen so far - this time the eclipse is coming to us. In fact, we could just step outside in our back yard in East Dallas and enjoy almost 4 minutes of totality. However, we have family a little south of here who live closer to the centerline and will get 4 minutes and 16 seconds of totality so our plan is to spend the day with family enjoying the view. As long as the weather cooperates, of course!

The last time, I was hoping to capture images with a long lens and also a wide angle time lapse. See link above for posts about that experience but unfortunately I had to skip taking pictures to still be able to see the eclipse with my own eyes (something everyone needs to see at least once in their lives). I did get the wide angle time lapse with a glimpse of totality through the clouds but the real treat was seeing it. 

This time I hope to both see totality as well as capture the experience through many other means. The primary goal is to capture the full eclipse, start to finish, through our small telescope, shooting with a solar filters for most of the eclipse and removing it only for those few minutes where the Moon has fully eclipsed the Sun. 

The list of other ways I plan to capture the eclipse isn't final and I am sure I'll have to give up on some of my plans but right now, in addition to the telescopic images, my tentative plans include:
  • a wide angle time lapse of the eclipse from beginning to end with our son's family chicken coop in the foreground
  • a long-exposure shot on film with a Brownie camera (a family heirloom) outfitted with a pinhole lens
  • the family being able to view the sun, sunspots and eclipse through a solar funnel attached to our other small telescope
  • video of shadow bands on a white sheet
  • aerial video captured with a drone of the lunar umbra moving across the landscape 
  • data collection before, during and after the eclipse using a variety of home made digital sensors based on a low-cost microprocessor called an ESP32, collecting information on the environment (temperature, humidity, pressure), sound levels, light levels and light color spectrum 
Stay tuned for more updates on my progress getting all this ready to go!

Wednesday, January 17, 2024

Experimenting with AI

Over the course of my career in technology, I gained an appreciation of the use of 'accelerators' — utilities, tools, and techniques that help get a task done more quickly than doing the same task by hand. Although I am retired now, I have various personal projects that involve some form of coding so accelerators are still useful. A new option that has really been a game-changer is ChatGPT. By describing the logic I need, it can sometimes provide complete, working code. At worst, it offers a foundation I can adapt, significantly cutting down the time it takes to create a new script or automation, especially in languages that I didn't use professionally like Python.

With the integration Microsoft has provided between ChatGPT 4 and DALL-E 3 under the covers of Copilot (previously Bing Chat), I decided to try my hand using it as an accelerator for creating images. For a few years now, I've had the idea of having a blog title image that highlighted the various interests I write about on this blog, primarily astronomy, photography and sailing: a nighttime seascape with a sailboat and the Milky Way arching overhead. As I have never received a response to my post seeking help from an artist, I decided to experiment with Copilot to create the image myself.

One thing I learned along the way is that creating with ChatGPT and DALL-E isn't like painting with a tool like Photoshop... there are limits to the degree of control you have. My original intent was to have the horizon centered in the image with a pretty plain foreground and limited detail at the top so that I could crop the standard DALL-E square image down to a landscape orientation. The initial images often placed the horizon lower or higher than specified, and revising the prompt didn't always affect its position in the final image. Similarly, I originally had specified having a single-masted sailboat yet every image generated had a two or three-masted ship. Anyway, it appears you have flexible about the details of the generated image.

After numerous passes, I started from scratch with the following prompt which didn't include a reference to a sailboat.

Create a photo-realistic image of a night-time  seascape with a calm sea with a large foreground of water and no land visible, with the stars across the sky an do the Milky Way rising high the the sky on the right side of the image, a low line of clouds along the horizon with a few small lightning bolts in the far distance and a full moon just above the horizon on the far left side of the image.

Of the 4 images generated, I chose the one that was closest to what I had in mind and provided a second prompt to add a small sailboat off in the distance, along the horizon. Here is the result.

This image came close to matching my original vision. The unexpected rocks under the water in the foreground were easily cropped out, although I left a few visible in the final version. Similarly, the Moon was up high instead of on the horizon but, again, not something I minded cropping out. Although the sailboat was a bit smaller than I'd like, I think it works well.

The one issue with this version is the reflection on the water in the middle. It's obviously not the Moon as that's at top right but it's not clear what it is a reflection of. The brightness on the horizon looks a bit like a sunset so perhaps it is supposed to be the Sun behind the clouds. I decided that I'm fine with the sky brightness but the reflection had to go.

Picking the image in Copilot opened it in Image Creator where I could pick Customize which opened the image in Microsoft Designer, an AI-powered design app. One of its features is 'generative erase'. Basically, all I had to do was select the reflection on the water with a brush and Designer replaced it by filling in that space with something that looked like everything around it. This is similar to the 'generative fill' feature in Photoshop. As you can see, it worked pretty well.

If you read the post linked above, you'll see that my ultimate goal was to have an image like this animated as a GIF. My research suggests that using existing AI tools for this is feasible, but it's not as straightforward as just giving ChatGPT a prompt. It involves creating and compiling a series of images, then employing tools like Stable Diffusion to convert them into a video, which can subsequently be saved as a GIF. It sounds like that could even involve writing code. Eventually, I may give that a try but, for now, I'm satisfied with just cropping this image down and using it as the blog title image for a while.

Your thoughts? Whether you love AI, hate it or are ambivalent, I'd like to hear about it in the comments.

As always, just click on an image to see it full screen!