March 14, 2025 Total Lunar Eclipse

[gdlewen]

I'm interested in seeing the images ST members have of the total lunar eclipse on 3/14/2025.

Here is mine, taken a little after totality. There is a bright spot which I think is the crater Aristarchus. What struck me was how the normally sharp features are blurred, and this is "real" because the edge of the moon's disk is sharp so the image is in focus. Also, I don't think the blurring is due to the fact the image is "darkened".

Nikon Z6; 200mm f/6.3 lens; Shutter Speed: 1/5 sec; ISO 1600​

Obviously the dark red color is due to scattering in the earth's atmosphere, but I never before considered that the atmosphere just doesn't redden the light, it also creates a diffuse annular light source that is very different from the plane-parallel light normally incident on the lunar surface--in the absence of the eclipse.

I'm doing a search for papers that quantify how this diffuse light affects imaging the moon's surface from the earth, but so far it is a bit slow. Lots of discussion of color-shifts and how scattering changes the light distribution across the lunar disk but so far none taking the extra step to discuss effects on subsequent imaging. (That's a long way of asking if anyone can provide some references.... Thanks!)

 

[Amelia Urquhart]

I shot this timelapse aiming to show the full progression of the eclipse from start to end. Clouds stuck around in south-central Kansas much longer than any model had forecast, so I lost the first ~10 minutes, but I got all the rest and I'm very proud of the result.

It seems like the blue color at the edge of the Earth's shadow was much more visible at the start of totality than at the end. I'm not sure whether that was caused somehow by my use of aperture priority to keep the exposure consistent across the timelapse, or an actual real-world effect.

I also made a still image using similar techniques to deep-sky astrophotography. 30 mph+ gusts degraded astronomical seeing conditions and also shook my tripod and tracker despite my best efforts to use my car to shield the imaging rig from the high winds, so the image isn't quite tack-sharp. Despite that, what blurriness there is is hard to notice and overall too minor to be distracting. Using the 32 images closest to maximum eclipse, amounting to 5m 20s of integration time, both the moon and the background starfield can be seen clearly.

I'm still planning to make a sequence composite, but I haven't gotten around to it quite yet.

 

[gdlewen]

These are very nice. Do you mind providing details of the camera, lens, and exposure parameters? There is clearly more detail in your final image but it is also better-exposed. [thinking….]

Next eclipse!

 

[Amelia Urquhart]

I used a Canon EOS R100 and an Astro-Tech AT60ED Telescope, which has a focal length of 360mm and a fixed aperture of f/6. It's all budget equipment since I'm on a college student budget, but for the price tags it's pretty good quality. I set my camera to aperture priority with an exposure compensation of -1 EV and tried to keep my ISO at 100 the whole time, but it ultimately needed to be bumped to 250 during totality. I had exposure parameters ranging from 1/500 f/6 ISO 100 during the penumbral phases to 10 sec f/6 ISO 250 during totality. I tried to write some code to plot a light curve for the eclipse and while it didn't turn out quite as pretty as I wanted, it might still be of interest.

Using a star tracker was critical for the exposures during totality. While I fudged the polar alignment, it was still close enough for individual exposures even if there was noticeable drift between exposures. I used a SkyWatcher Star Adventurer 2i, and had to shield it behind my car for the full duration of the eclipse to keep the ripping southerlies from shaking my rig too much.

The still image I posted was composited using Siril and Image Pattern Alignment. Siril has a steep learning curve so I would recommend only using it if you either have prior experience or you're not satisfied with the results of a single exposure.

 

[gdlewen]

Thank you for the very detailed description! There are significant differences between our set-ups that make it difficult to compare results but one takeaway message for me is that the blurriness of my image probably has nothing to do with diffuse scattering in the atmosphere. (That's a very big deal and it saves me some reading....)

 

[Amelia Urquhart]

I think your blurriness is probably the result of denoising. If you shot in JPG then your camera might've applied some very aggressive denoising setups. I have a bit of blurriness too, but I'm guessing it's to blame on mount instability.

 

[gdlewen]

I used a RAW file for the ST post and processed it gently (the best word for it, really) in RawTherapee because I was unsure where I was going. I will go back and check the settings I used. I don't know how much time I will spend on it for a while, because The Bill (HB2426) is heading to the OK Senate and I am committed to doing all I can to stop it.

BUT: it is good to know that I can do better than the image I posted. Very valuable feedback, for which I am grateful.