Shooting a solar eclipse

[AlphaLG]

Does anyone have recommendations on a suitable filter for shooting a partial solar eclipse? There is one coming up in June and I’d like to get a bit of practice in before then.

 

[Astrnmrtom]

Your best bet is to get a small sheet of Baader Solar film and some cardboard to fashion a filter you can place over the lens. Just do a search for Baader Solar film. It's available in various sizes and is quite inexpensive. Here's a link to an info page that even includes instructions on how to make your own solar filter using the film: https://astrosolar.com/en/ You can purchase the film in many places including Amazon. It's 100% safe for both your camera and visual use. I own and image with some very expensive solar equipment and Baader film is near the top of the list when it comes to resolution, and it's the cheapest option. One important thing to note is, the Sun is near it's minimum of the 11 year activity cycle so can often appear completely featureless. If you are lucky there might be a couple small sunspots, but that's it. One fun thing to do with white light solar imaging is to do a series of images spaced a few minutes apart starting with first contact and ending with last contact. Then combine them into a collage or even an animated giff of the eclipse. The hardest part will be keeping the Sun centered in the frame for each shot. Well, the first hardest thing will be to even find the sun and center it with the filter in place. Obviously if you are using a zoom, start at the short end, center the Sun, zoom in, occasionally re-centering until you are at full zoom. The other thing you want to practice with is focus. Good news is the solar disk though the filter will be extremely high contrast so most autofocus systems will lock on quite well. If not, and you must focus manually, one trick that's worked well for me is to rock the focus back and forth a few times while watching the image. By doing this you'll get a better sense of where best focus is. If all else fails, bracket your focus. Use a remote, the 2 sec self timer, or even Sony's touchless remote trigger app to eliminate shake because you'll want to use whatever long zoom you have for best image scale. One mistake a lot of people make when imaging the Sun is over exposing the image. If your exposure is too long the camera will pick up faint light leaking through the filter causing a halo around the Sun's disk. You want the Sun's disk to be surrounded by complete blackness.

Oh, if you want to do some practice centering, zooming, and imaging before your filter arrives, shoot the Moon. It's the angular same size as the Sun and is a good proxy for getting a feel for how your camera/tripod/techniques work.

One last warning. Be SURE to attach your filter so it can't easily be blown off while you camera is pointed at the Sun!

Good luck, and please share your images and if there's anything I can do to help, feel free to ask.

Tom

 

[pointreyes]

I used the Formatt Hitech Firecrest Solar Filter ( https://www.bhphotovideo.com/c/prod...h_fc77eclp5_4_firecrest_77mm_eclipse_5_4.html ) back in 2017 and ended up with results like this:

Eclipse - Hull Family

This gallery hosted by SmugMug; your photos look better here.

www.zhullfamily.net

Taken on a Fujifilm X-Pro2 with a cheap 1.4x TC on a used Nikkor 80-400. Color was not adjusted.

I practiced using that filter for a month testing on the Sun. One thing I did learn was to bracket so that if you mess up on the exposure you might have a good one in the bracketed shots. I was surprised that the jpegs were good enough and so never bothered to process the raw files I had. I also had a wireless shutter remote so that I could enjoy seeing the effects of the eclipse without having my eyes glued to the LCD. I got to enjoy interacting with others and only would adjust the camera for when the eclipse needed to be centered in the frame again. That also made it possible for me to have a second camera to record the effects around me and every once and a while trip the shutter from a far.

 

[Astrnmrtom]

Although not directly Sony camera related, I can share a couple pics of the 2017 eclipse taken through the h-alpha filter, and in white light using Baader film since we are talking about what to use for photographing a solar eclipse. The one that shows the spots clearly is using the Baader film. The other is taken though a narrowband h-alpha filter which shows a layer of the sun about 1000 miles above what is seen in the white light photo. This reveals hot plasma flowing along magnetic field lines. You can see where there's a lot of magnetic field activity where the sunspots are, and this is what causes the sunspots to form. Bright areas are hotter gas, darker features cooler. The h-alpha picture was taken a few minutes later than the white light one so the Moon's limb is beginning to intrude into the sunspot area. Images were shot with a small monochrome sensor, 658mm focal length f/7 lens. If shot using any camera on this forum, the entire disk of the sun would be visible at this focal length. One sign the seeing conditions are good, and the filter is a good one, is the grainy look to the Sun's surface in white light. You can see it in the first photo. This is solar granulation and consists of plasma convection cells about 1000 miles in diameter. The third image shows what is possible in good conditions with enough focal length. This was a large spot group visible a month after the August eclipse, and before the Sun went into it recent quiet phase. The main spot is big enough to easily drop the Earth into without touching the sides. A sunspot is a place where the Sun's magnetic field gets twisted up in knots, emerges from the surface, peeling back a layer of plasma allowing us to look deeper into the surface where it's cooler. The center looks black, but in reality isn't. it's just emitting less light that the surrounding surface. Seen by itself, it would still be bright.

Oh, speaking of seeing conditions. When you go to photograph the sun, you'll want to avoid doing so over hot pavement. If possible set-up on grass or a surface that doesn't radiate heat. Hot pavement will cause the local air to churn, blurring the image especially if you are shooting with a long lens. Same goes for shooting over the top of a hot roof or building. This advice goes for shooting astronomical targets at night too. Twinkling stars are pretty, but they are a sign of turbulent air. Shooting over hot pavement day or night makes it worse.

I' wish I'd saved them but I have a friend who images the Sun through his scope using Baader Astrosolar film and his NEX-7. He gets wonderful results. I'll see if he can send me some so I can show you what can be done with an ASPC camera, some cardboard, and some inexpensive solar filter film.

Tom

White light, w/Baader AstroSolar Film.

H-alpha 656nm in the red

Close up of large sunspot group. I'm guessing this photo was taken at about 3000mm effective focal length @ somewhere around f/24. High focal lengths are brutal at revealing dust motes on your sensor. :^(