April 8th 2024 Total Solar Eclipse: Fine Detail in Corona

I went down a bit of a rabbit hole this week, assuming that to really get sharp detailed images of totality I needed to go through the rather involved process of using calibration frames to process all of the images I planned to stack before trying to stack, register and merge them. After spending a few evenings starting down that road, I took a break and in reviewing tutorials on processing solar eclipse images I ran across several that describe doing everything directly in Photoshop without the use of registration frames. 

Following the process described in this Sky & Telescope article, I created the image above using a set of images shot at 2 stop intervals from 1/4000th of a second to 1 second, all shot at f/5 and ISO 100 with my Nikon D750 through our Sky Watcher Evostar 72ED telescope. 

Click on it to enlarge and check out the incredible detail. You'll find features like:

• Plenty of detail in the solar corona
• Solar prominences
• The lunar surface illuminated with light reflected from Earth (Earthshine)
• Several stars from the constellation Pisces

This is just the first phase of edits described in the article so more to come. In the meantime, I did a separate version with features labeled. 

October 14th, 2023 Annular Eclipse Timelapse

 

Unable to make it to a spot on the path of the annular eclipse today to view the Ring of Fire, I captured this timelapse of the partial eclipse view from my backyard. 

What's great about successfully capturing this eclipse that I wasn't even home! Since our granddaughter Harper was showing her rabbit at the State Fair of Texas stock show today, I had the equipment set up to run automatically. Months of preparation and practice paid off! BTW, more to come on the State Fair....

The shadows on the first few seconds are power lines which appear to move across the face of the Sun but it's the Sun's apparent motion across the sky, tracked by the telescope/camera, that accounts for the motion. 

This view was captured with a special solar filter, a Baader solar film filter. Without it, pointing my telescope and camera at the Sun would have damaged my equipment. 

As we are approaching "solar maximum", the Sun is pretty active so there are plenty of Sunspots across the face of the Sun right now. 

Here's what I used to create this timelapse. I set the internal intervalometer on the D750 to take shots every 30 seconds at 1/1000th shutter speed from just before till just after the eclipse, about 380 shots in all. Just to be sure I didn't have to worry about batteries in the camera and tracker lasting long enough, I ran everything off an external power pack stored under the tripod. You can see the equipment in action in my post on eclipse preparations. 

Equipment

Sky Watcher EvoStar 72ED Refractor

Sky Watcher 0.85 Flattener/Reducer

Sigma 2X Teleconverter

DeepSkyDad AF3 Autofocuser

Baader Solar Film Filter

Nikon D750 DSLR

Sky Watcher Star Adventurer 2 Tracker

Radian Carbon Fiber Tripod

Processed on Mac OS with 

Adobe Lightroom Classic

LRTimelapse

DaVinci Resolve

Music

"Eclipse"

by 1st Contact

Shared under Creative Commons License

Attribution-ShareAlike 4.0 International License

https://freemusicarchive.org/music/1st-contact/single/eclipse/

Preparations for the Annular, er, Partial Solar Eclipse!

Tomorrow's the day! As mentioned in my last post, tomorrow an annular solar eclipse is visible across a stretch of the western half of the North American continent. 

For the rest of the country - including Dallas where I live - we won't get to see the Ring of Fire but we'll still get to observe a partial solar eclipse. 

Screen shot from Stellarium

Here is what the Sun will look like at maximum eclipse for Dallas (about 11:52am local time). Although that area blocked by the Moon in this simulation looks blue, keep in mind that this is a new moon which means we don't see any illuminated lunar surface since the Moon is in between us and the Sun. 

While you would think that with this much of the Sun covered up the amount of light we see would be low enough to be safe to view without eye protection, it's not! Except during the totality phase of a total solar eclipse when the Moon is completely blocking the solar surface, it is not safe to look directly at the Sun. If you are interested in seeing the eclipse tomorrow, only do so if you have a set of solar eclipse viewing glasses from a reputable source. If you don't already have eclipse glasses it may be too late to get some but here is information from NASA on safe viewing resources. 

Personally, I am treating this eclipse as a trial run for the total solar eclipse that will pass over North Texas on April 8, 2024. I plan to capture the partial eclipse from start to finish using my Nikon D750 and EvoStar 72ED refractor telescope with solar filter mounted on my Star Adventurer tracker. I'll leave it running from well before the eclipse through past the end of the eclipse, capturing a couple of shots a minute. Hopefully, the result will be a handful of good shots of different stages of the eclipse and possibly a sequence of shots I can use to make a timelapse video of the eclipse from start to finish. 

A lot has to happen for this to be successful - a good polar alignment of the telescope the night before, being able to get a good focus of the Sun once it peeks above the trees, the weather forecast being accurate (i.e., no clouds) - but even if it doesn't work out as planned, it will still be good practice for April!

Here are shots of my equipment set up for a test run today. 

That solar filter is critical for
safely photographing the Sun!

The tracker keeps the telescope pointed
at the Sun as it moves across the sky.

I hope you get to see the eclipse, too. Just be sure to be safe when viewing the Sun!

Solar Transit of a Jet

UPDATE: I've replaced the previous video with a new version that includes the sound of the jet flyover from the original audio track. 

While out filming the sun to practice for the total solar eclipse next April, I was photo-bombed by a jet! 

The technical term is "transit", when an object crosses in front of an astronomical body. There is plenty of air traffic over our house with Love Field and DFW serving the area so I guess this shouldn't have surprised me but observing a transit (like this one, or this one) takes being in just the right place at just the right time so it's a pretty rare thing to have happen. 

One reason I happened to be shooting at this time is that I'm working out exactly what equipment I'm going to be shooting with for the total solar eclipse. This video was shot using:

• Sky Watcher EvoStar 72ED refractor
• Baader film solar filter
• 2" mirror diagonal
• Celestron 1.25" 2X Barlow
• T2-ring
• Nikon D750 DSLR
• Focusing with DeepSkyDad AF3 autofocuser
• Sky Watcher Star Adventurer 2 tracker
• Radian carbon fiber tripod

I have a new 2" 2X Barlow and I plan to shoot straight-through (i.e., no diagonal) but I am still working out what combination of components will allow me to properly focus with the new Barlow. Once I have that worked out, I'll start working on automating my astrophotography workflow using a small computer (a Raspberry 4 running software called StellerMate).  

The quality of this video isn't great but that's basically because I was focusing (pun intended) more on getting the equipment working right than on the finer details. Next April may see a long ways off but it will be here in the blink of an eye and as I know from my experience in 2017, being ready to catch a full eclipse end-to-end, most importantly those few minutes of totality, takes an incredible amount of practice. So, I'll be shooting pretty regularly over the next few months to make sure I have everything working perfectly. 

Anyone have a way to ensure that April clouds don't spoil the eclipse for me, er, us?

Seriously, you'll notice from the video that the Sun is pretty active with quite a few sunspots showing. Over the next few weeks, if I can get a day with good "seeing" (i.e., where there is minimal air turbulence), I'll get some shots with lots of detail, everything in focus, and the sunspots should jump off the page at you. Stay tuned!

Warning 

NEVER look directly at the sun without proper protection. This video was shot using a telescope and camera equipped with a special solar filter.

Blue Moon Rising Over White Rock Lake

UPDATE [August 20, 2024]:
If you have followed the news you know there was a Blue Super Moon yesterday. However, it was different from the one I wrote about below. The one last year was a monthly Blue Moon, while the one yesterday was a seasonal Blue Moon. A monthly Blue Moon is the second full moon in a calendar month, whereas a seasonal Blue Moon is the third full moon in an astronomical season with four full moons, occurring between an equinox and a solstice. Why is the 3rd instead of the 4th full Moon in a season the Blue Moon instead of the 4th? Good question! If you know why, share it in a comment.

As for being a Super Moon, that label applies to both the full Moon yesterday and the one for last August although last August the Moon was slightly closer to Earth (about 2,700 miles closer).

With the extreme Texas heat, lately I've been waiting till after sunset to take our Weimaraner, Luna, for a walk and we've been walking along the shore of White Rock Lake near where we live since it's often cooler with a little breeze coming off the water. 

I had not planned to shoot the Blue Moon tonight, but after my wife Linda asked if I would be, it occurred to me that it would be visible over the eastern shore of the lake when Luna and I were out walking. I decided to see if I could get a shot of the full Moon rising over the sailboats at Corinthian Sailing Club before our walk. I grabbed my small refractor (Sky Watcher EvoStar 72ED), my Nikon D750 and a tripod, loaded Luna in the car and headed to the lake. 

Apparently, so did everyone else. I guess the news of the Blue Super Moon got enough press that lots of other people showed up at the lake to watch it rise and traffic driving up the west shore was like rush hour. By the time I was parking the Moon was already well above the tree line. I hastily set up the scope and camera, got a reasonably good focus on the Moon and started shooting. All the while, Luna hung out with me, thankfully only wrapping her lead around the tripod as I was finishing up. 

Ironically, the shot below was the first shot I took. Of all the others, I could perhaps merge a few bracketed shots for something with a higher dynamic range but frankly this is pretty much the shot I had in mind when I left the house. 

Enjoy!

As always, click on the image to see full-screen. 

The Moon and the Pleiades

There are plenty of interesting sights in the night sky each year. Headlines right now are touting the 5 planets that'll be visible this week, unique because it will be easier than usual to spot Uranus (though you might still need binoculars for it and possibly for Mercury). Unfortunately, I don't expect to see that given the current forecast for cloudy weather in North Texas. 

A sight that didn't get much press but that I looked forward to was a conjunction this past Saturday evening (March 25th) between the Moon and a star cluster called the Pleiades, also known as the Seven Sisters, or Messier 45, or Subaru in Japan or many other names across time and cultures. If you ever stared up into the night sky on a winter or spring night and saw what looked like the Big Dipper but almost so small you weren't sure that's what you were seeing, that was probably the Pleiades. 

The Pleiades is located in the sky just shy of 5 degrees off the ecliptic. As that's the path that the Sun, planets and the Moon generally follow across the sky, it's not uncommon for the Moon to pass near this star cluster. But many times it occurs during the daytime, or when the Moon is full or nearly full or the Moon doesn't pass close enough to the Pleiades to appear in the same telescopic view. So seeing a conjunction of the Moon as a crescent (just five days after its New phase) and the Pleiades is not that common. I've been told this occurs about every 12 years though I haven't been able to find a concrete source for that. 

To capture this event, I drove out to Terry Park on the east shore of Lake Ray Hubbard so I would have less light pollution to deal with than at home and so that I had a clear western horizon to allow the longest amount of time to shoot between the end of twilight and when the Moon set. For this session, I used my Evostar 72ED refractor telescope, Nikon D750 camera and Star Adventurer star tracker. 

Here is a raw, unprocessed image from my session on Saturday night. 

5 day old waxing crescent Moon with Earthshine passing near the Pleiades

This is not entirely what I had in mind but it's just one of the many shots I captured. I'm working with the full set of images to come up with a shot that addresses the challenges in taking this shot. 

• In this image, the sunlit side of the Moon is overexposed. I also have shots with the sunlit side properly exposed but the shutter speed for those shots was too fast to capture the stars of the Pleiades. I am working on a blend of this shot and the other one. It's a tough edit so wish me luck.
  BTW, the shutter speed for this shot was 2 seconds while the shot with the sunlit side properly exposed had a shutter speed of 1/160th of a second. That's a huge difference, over 9 f/stops apart. Although our eyes can see such a broad dynamic range, most cameras cannot, hence the need to blend multiple images.
• I still want the final image to have the rest of the Moon also dimly illuminated. This is called Earthshine because, well, it is the result of sunshine reflected off the Earth lighting up the part of the Moon that's not lit by the Sun. 
• I want to bring out the stars of the Pleiades better so that they aren't washed out by the Moonlight. However, it will just be a matter of the individual stars being a bit brighter.
  If you have seen images of the Seven Sisters like this one with lots of blue nebulosity surrounding them, it wasn't possible to capture the reflection nebulae that surrounds the stars of the Pleiades with the bright glare of the Moon so close by. 

I'll describe the post-processing I'm doing when I post the final image. 

More to come. 

As always, click on the image to see big.

PS. Here is my EarthSky community photo post of this image.

The Green Comet

Well, the first thing that came to mind seeing news headlines about The Green Comet was a flashback to the 60s TV show The Green Hornet staring Bruce Lee. :-)

Seriously, this has been a newsworthy comet. While it wasn't bright enough to be seen except under very dark skies and/or with optical assistance like a telescope, as you know if you've followed the news, it is a singularly unique solar system visitor. Check out sites like EarthSky.org for more details and some of the more interesting images. 

For my part, I had hoped to capture comet C/2022 E3 (ZTF) with my rig (Evostar 72ED on a Star Adventurer tracker, using a Nikon D750). Unfortunately, the North Texas weather hasn't cooperated. Last week when it was at its closest to Earth (and at its brightest magnitude), we were in the throes of a winter storm. By the time we had a night with relatively clear skies on Friday night, we also had a nearly full Moon. It was also still very cold outside. If it had been a moonless night, I'd have packed things up and headed out east of town to darker skies to shoot but since I knew the Moon was going to make it hard to get really good shots, I just set up in my backyard. At least I could duck inside from time to time to warm up. 

Here is the result. See below for more on how it was created. 

Comet C/2022 E3 (ZTF) captured in my backyard
February 3rd, 2023

Between the light pollution and the glare of the Moon, it was hard for me to pull out much detail but you can at least see the dim fuzzball of the comet's core. The comet was in a region of the sky without any bright stars but the few brighter ones on the right side of the image are in the constellation Camelopardalis.

Still, it was time well spent. It was the first time I've gone through the process of capturing what are called calibration frames (bias, darks, flats), additional shots taken to improve astrophotography images by accounting for things like sensor noise and dust. It is also the first time I have processed using calibration frames; I took 100 images (20 seconds each) and post-processed them and the calibration frames using a software tool called Siril and then finished in Photoshop. 

Capturing a comet is often tricky since it is moving at a different rate than the stars. Using a star tracker (vs. a telescope mount), my only choice was to track the stars and hope to be able to post-process the comet and stars separately then combine them afterwards. I did that but it took a long time and many tries just to get the results above. I wish I had more data but longer exposures weren't possible since the histogram showed that any longer than 20 seconds at ISO 3200 would have resulted in clipping (i.e., the blue was almost lost to the right side at 30 seconds). On top of that, the comet would have blurred if I used too long an exposure given how fast it was moving.

One of the other tools I learned how to use is Astrometry.net which can do something called plate solving, taking an image and finding where in the sky it is a view of. Here is the results of plate solving using one of the images used to create the shot above. I find this raw, astrometrically-labeled view an interesting alternative version of my night's labors since the comet (though not green) stands out a bit more.

The three dots and labels represent stars in the constellation
Camelopardalis identified using plate solving on astrometry.net

Anyway, the next time I am shooting a dim fuzzy (hopefully without the Moon up and away from city light pollution), I'll have had some practice and expect to be able to produce much better results. 

Stay tuned...

Click on an image to see full-screen. 

HST Transit Attempt: Failure is How We Learn

I camped out in Chris and Katie's backyard last night with my Nikon D750 and telescope (Sky Watcher Evostar 72ED) to try and capture a transit of the Hubble Space Telescope (HST) across the face of the Moon. Unfortunately, I didn't capture it. I'm not too surprised... stories from people who have captured a lunar transit of the International Space Station (ISS) often describe making 4-5 attempts before success and the ISS is about 10 times as large as HST in the sky (between HST being both physically smaller and about half again further away). 

This was my second attempt at a lunar satellite transit. I'd done a test shot of a transit of the Chinese Space Station (Tiangong) a few weeks ago. For that one, I had tried shooting a rapid series of shots but with the transit only lasting about a few seconds, I just was not shooting fast enough to capture it. That led to my plan for last night to try shooting 60 frame per second video with the goal of using individual frames to create a composite image. Assuming I had captured anything. Which I didn't. :-(

The evening wasn't a total bust though. On the one hand, I got useful information about trying to shoot video to capture something like a lunar transit. The high ISO I used resulted in far too much noise, so much so that I suspect the HST is there in my video but lost in the noise. I need to do some night time Moon video test shots to see how low I can set the ISO and still get decent video. I also learned that trying this when the moon is so close to the horizon (it was at only about 11 degrees, just above the trees along the back of their property) just makes it tougher since with it that low means shooting through more atmosphere and there is also more air turbulence. 

The end result of the evening (besides the things I learned) is this hazy shot of a first quarter moon, created with some editing in Photoshop to merge two images; one with the Moon properly exposed and the other with the high, thin clouds showing (but in which the Moon was completely washed out). 

Learning something new every day! 

July Waning Gibbous Moon

As a follow-up to the supermoon shot in my previous post, last night I spent time fine-tuning my technique for shooting the moon with the equipment I described in that post. Here is the result. 

The main difference is that for this shot I added a 2X teleconverter to increase the focal length. A longer focal length results in higher resolution for the subject, in this case, the Moon passing from full phase to gibbous phase. 

The Evostar 72ED has a focal length of 420mm. It's necessary to use the 85% focal reducer/corrector to capture images through it with a camera so that reduces the effective focal length to 357mm; that was what I used for the image in the prior post. Adding the 2X teleconverter increases the effective focal length to 714mm. The resulting higher resolution provides greater detail in this image. 

This photo is the result of stacking the 3 best of 12 shots using PlanetarySystemStacker. I then followed this tutorial to post-process the image in Lightroom Classic. While some of the improvement over the last image is due to the post-processing, I think that overall this is a much better shot thanks to using the teleconverter and spending more time getting as sharp focus as possible. 

Enjoy!

July 2022 Supermoon

As reported on EarthSky and other sites, the full moon yesterday was the closest and brightest of 2022, fitting the definition of what is now commonly referred to as a supermoon. It was cloudy to the east when I went out to the north shore of White Rock Lake to capture it rising over Corinthian Sailing Club so initially it wasn't visible but it eventually started peaking out of the clouds, appearing very orange. Here is the shot I captured with a Nikon D750 attached to our Evostar 72ED telescope and 85% focal reducer/corrector mounted on our Sky Watcher Star Adventurer tracker. This is the result of processing 150 shots, first cropped and exposure adjusted with Lightroom Classic and then stacked with PlanetarySystemStacker to get a cleaner, sharper image.

This is a pretty crude result as I am still learning how to get optimal focus with the camera on this telescope, how to balance the tracker to improve stability and how to use the stacking software. More to come...

While I was shooting this, I had another camera taking shots for a timelapse video of the supermoon rising over the sailing club and the lake. I'll post that after I have time to work on editing and rendering it. 

Click on the image to view full screen. Enjoy!

First (and Second) Light with New Equipment

Earlier this year, we started on the journey to replace our older telescopes, a Parks 60mm refractor (currently for sale) and an Orion 8" Dobsonian reflector, with something lighter and smaller. The new telescope is a Sky Watcher Evostar 72mm ED apochromatic refractor. It is under 18" long and only weighs a touch over 4 lb so it's very portable. On a solid mount and using our Sky Watcher Star Adventurer tracker, it makes a very nice platform for both visual and photographic views of the sky. 

The telescope itself is optimized for viewing large but dim structures like galaxies and nebulae but with the right optics it works well for wide-field views of the planets, the Moon and the Sun. Of course, for solar viewing, it takes more special equipment. As with our other telescopes, I opted for one of the more affordable solutions, a filter made of Baader solar film. I had ordered Baader film from the Baader Planetarium but I needed a holder to fit the new Evostar. Instead of creating one from scratch out of cardboard as I did for the 2017 Total Solar Eclipse, I searched online and found a design on Thingiverse. Thanks to Dari Esfahani for creating it for me on his 3D printer. 

Here are shots of the finished filter and the new telescope.

On Friday, I set up the telescope and filter in the backyard. The view was great as there is plenty of sun spot activity right now (see SpaceWeather.com). I grabbed a shot through the eyepiece with my phone as it was too hot (105°) to take the time to mount my camera on the telescope. This morning before it got so hot, I tried again with the camera mounted on the Evostar. So, here are the "first light" and "second light" shots for the new solar filter. 

Taken with Pixel 5 cell phone through  eyepiece on Evostar 72ED

Taken with Nikon D750 mounted on Evostar 72ED

The shot taken with my phone isn't quite as clear and it has some odd artifacts from how the phone camera processed the image but otherwise, it isn't too bad. The shot through my Nikon D750 is sharper though I was a bit rushed and I think I can get even sharper focus the next time. As for the differences in the sun spots between the two images, it is in part because the orientation of the phone camera yesterday vs. the Nikon this morning plus a small difference in the size and location of each sunspot due to the time that had elapsed between each shot. 

With the new solar filter, I'll be spending more time watching and photographing the surface of the sun. Stay tuned!

As always, click on an image to see full-screen.