03-16-2017 09:33 AM
I think I have demonstrated that I have shot the sun, both with and without a filter - but I only went filterless in those few moments at sunset - when I had to work *fast*.
Everone agrees that you need to track, but you do not need a tracker which are generally more useful for long exposures.
03-16-2017 10:43 AM
kvbarkley the statement was general not specific. I saw your very nice shot. But it does depend on what you want as to how it can be accomplished. The moon is a good 'test' subject and most people start there. Size for size and opportunely.
04-05-2017 02:05 PM - edited 04-05-2017 02:07 PM
I realized I should probably comment on some of this. I recently gave a presentation at an astronomy conference on the topic of photographing the solar eclipse. "The" expert on the topic is a guy named Fred Espenak. Fred is a retired NASA physicicist who still does their eclipse predictions (even in retirement). If you've seen those maps that plot the path of totality across the country... those are all his work. He's the guy responsible for this eclipse prediction (so if he's right, you have him to thank and if he's wrong you have him to blame. But he's VERY GOOD at this.)
Anyway, I happened to set next to him at a lunch and discussed some of the aspects of eclipse photography in a bit more detail than was offerred at the presentation. I've done lots of solar observing (I own quite a number of solar filters, a herschel wedge, and a dedicated hydrogen alpha solar telescope). I've photographed partial eclipses... but never a total solar eclipse.
I never talk about the sun without bringing up the topic of safety.
The sun pumps out nearly as much energy in the infrared spectrum as it does in the visible spectrum. That's why you feel warm when you stand in sunlight. If there were no infrared, you wouldn't feel the heat (it'd be a bit like using LED lighting).
MOST welding glass is NOT SAFE for use with your eyes. Welding glass used to be smoked glass. Today it's mostly modern polymers that are designed to eliminate the spectrum harmful to the welders eyes (mostly in the visible spectrum and mostly toward the UV end) but not so much in the IR.
You ONLY want to use a filter that is known to be intended for and safe to use with the Sun. As I tend to joke when I give these presentations "Do NOT stare DIRECTLY into the Sun with last-remainging functional eyeball."
Incidentally there are no pain receptors in your eye... as you torch your retinas, you wont feel it. The retina doesn't stop working instantly... it takes about 24-48 hours for the effects to set in. So you may do something unsafe, think you are ok because you aren't blind at the end of the eclipse... then wake up a day ... may be two days ... later and realize you don't see so well.
Spend the money for a proper solar filter before the eclipse... or spend the money for a white cane after the eclipse. Your choice. ;-)
On the topic of partial phases...
Ernie is right... it is NOT SAFE to look at ANY PARTIAL PHASE without eye protection... even 99% eclipsed isn't safe. Only when the ecipse is 100% (totality) is it safe to remove all eye protection.
Why? I illustrate this on the white board when I give my presentations... don't think of the sun as being 1 point of light deliverying energy to just 1 point of on your retina. Instead... think of it as lots of points of light being emitted and focused to lots of points of light on your retina. When the eclipse is ... say 50%... what that means is that 50% of the sun is covered. But the light emitted from teh 50% which is still visible is just as bright as it ever was. This light is now being focused onto a smaller area of your retina. So if you consider a single cell at the back of your eyeball... that single cell is getting just as much light intensity as it would get even if there were no eclipse. Covering part of the sun just means fewer cells are exposed to light. But those cells which ARE exposed to light will be damaged just as quickly as would occur if there were no eclipse.
Hopefully that covers the safety topic. I don't advise using welding glass. The heat build-up in your camera may be considerable because most welding glass doesn't block infrared and the heat buildup is happening the infrared part of the spectrum.
Most solar filters are ND 5.0 which means they block 16.66 photographic stops of light. A proper solar filter blocks both visible and infrared. That works out to mean that the filter blocks 99.999% of all the energy... or in different terms, 1 photon out of every 100,000 will make it through the filter.
We refer to these as "white light" filters not because the sun will appear "white" per se (although it could) but becuase the entire spectrum is allowed to pass through the filter... but only a very tiny amount of light at each wavelength.
Usually these filters do not block all wavelengths evenly. The Thousand Oaks filters are designed to block the blue and green wavelengths a little more than the reds... this causes an orange-bias so that the Sun has a somewhat familiar "red/orange" color to it (the sun actually is "white" in human vision but human vision is less sensitive to reds... in truth it's a slightly yellow star. The spectral classification for our star is G2 on the HR diagram.)
Baader film usually blocks the reds a bit more and these often result in a sun that looks white with a slight blue tint.
I happen to own a special device called a Herschel white-light wedge and based on it's designed it actually delivers true color. When I use that device on my scope the sun actually appears "white" with no color cast whatsoever. (it's not a simple filter... it's used like a mirror on a 45º angle and in which only .001% of the light is reflected and the rest of the energy is passed through to a heat sink (which does get hot). The caveat for this device is that it goes on the back of the scope, there is no energy rejection filter on the front of the scope, and they generally shouldn't be used on any scope that has an objective aperture greater than 100mm / 4in diameter ... to avoid heat build-up in the scope that can damage the scope.
BTW... the heat build-up problem is real.
For anyone who doubts this, I offer exhibit A:
I am the person holding the finder scope and speaking in this local-access show. But this finder-scope was on a larger telescope that was pointed at the sun. The main-telescope had a safe-solar filter. But what the owner of the scope did not know is that one of his friends had removed the cap from the front of his finder scope (thinking they needed to use the finder scope to help find the sun (very bad idea)) but hadn't gotten around to removing the back-cap. The owner pointed the scope at the sun and within moments he smelled burning plastic.
If you watch the video, you'll see a hole melted clear through the back cap.
Additional the cross-hairs inside the finder scope are metal wires... both of which snapped from the heat.
So if you want to point your camera directly at the sun at mid-day without filter out both visible and infra-red (that's where all the heat is) energy, that's up to you... but my camera will have safe solar filters on the lens at all times other than the short period of totality.
TIPS (from Fred Espenak's talk):
I took good notes when Fred was giving his talk on Solar Eclipse Photography and I'll share this with you. These tips assume you are viewing from a location which will experience totality.
I do own a solar filter that is threaded onto the front of my lens... but I also own Thousand Oaks filters that cap over the lens. I prefer the "caps" because in that window of time between 50 seconds and 10 seconds prior to totality. You will want your camera set to manual focus and you'll need to be able to remove the filter without accidentally altering the focus. I find I can get the cap type filter removed more quickly and without adjusting focus.
Using some gaffers tape to prefern the focus ring from turning (once you've refined focus) might not be a bad idea. I always have gaffers tape in my bag.