Well, this will be the last post in my lifetime on the transit of Venus in front of the sun. We have a couple of reader photographs of yesterday’s rare astronomical event.
The first comes from reader Pete, who calls our attention to his group of ten photos on his online album.
The photos were taken with Canon EOD 7D using a 70-200mm f/2.8 lens (at 200mm, obviously!) with a 2x teleconverter, yielding an 400mm effective focal length, or about a 13x zoom compared to a “standard” 30mm focal length for that body. I placed a 1000x (10-stop) neutral density filter on the lens, but even so had to use 1/8000s exposure at around f/16 for a reasonable exposure. Focus was manual using the LCD “live view” with 10x magnification to try to get as sharp an image as possible.
Interestingly, for this purpose it was better to use the 7D over my newer and higher resolution EOD 5D Mk III body, because in spite of the higher total pixel count, fewer of the 5D3’s (larger) pixels would cover the image. This is generally true for astronomical subjects: higher pixel density in the sensor is more important that a high pixel count, as long as noise is kept under control.
‘The videos and images displayed here are constructed from several wavelengths of extreme ultraviolet light and a portion of the visible spectrum. The red colored sun is the 304 angstrom ultraviolet, the golden colored sun is 171 angstrom, the magenta sun is 1700 angstrom, and the orange sun is filtered visible light. 304 and 171 show the atmosphere of the sun, which does not appear in the visible part of the spectrum.
Thanks, Jerry. Subscribing, obviously 🙂
That last shot is absolutely beautiful—and it’s almost what I would have seen this morning just after 5am but for my lack of proper viewing equipment… 🙁
And I had stayed up all night just to see it…
Sweeeeeeeet guys! Thanks for posting as I missed the transit (I was in my guitar lesson …)
{Dame Edith Evans as Lady Bracknell}
Gui-TAR les-son?
{/Dame Edith Evans as Lady Bracknell}
I at least have the excuse that there was a thunderstorm in the night, it clouded over just before the transit began and stayed clouded over all day. (The rest of the country had up to a metre of snow.)
Well, I suppose that would be my cue….
Pete’s quite right in that higher pixel density generally wins when you’re distance limited (you’re using your longest lens and can’t get any closer to the subject). I shot with the 5DIII that Pete didn’t use (since I don’t have a 7D), but instead of a 70-200 with a 2x teleconverter, I used a 400 f/2.8 with a 1.4x teleconverter, equalling 560mm. As you can see here:
http://www.canonrumors.com/forum/index.php?action=dlattach;topic=7074.0;attach=21229;image
even though I was using a longer focal length and a lower-density sensor, I wound up with pretty much exactly the same pixel dimensions for the Sun. What all that extra glass and weight and what-not got me, though, was a bit more sharpness.
(The color difference is due to white balance. I don’t know what Pete used, but I chose a color balance that rendered the Sun as a neutral gray; with the filter, that worked out to 5850K with -11 tint (meaning the filter imparted a hefty magenta bias). I re-used the exact same white balance for the sunset, so the color changes are due entirely to atmospheric effects.)
I had the 2x teleconverter with me, which would have resulted in more pixels-per-Sun, but the image would have been slightly softer and I wouldn’t have gotten as much of the skyline in the frame. In retrospect, with the cropping I wound up doing, it might have been a better choice, but it would have been riskier.
Oh — and, in place of Pete’s 10-stop ND filter, I used a Baader solar filter, basically a sheet of silvered (aluminumed) plastic. I tried taking it off shortly before the Sun hit the horizon, but I lost the sunspots. I might as well have left it off…I was shooting three-shot +/- 3EV brackets with the intention of doing an HDR composite, but even at 6 frames per second the Sun moved too much between frames for me to get good results that way…so I settled on the overexposed version, which preserves the skyline but at the expense of the sunspots, pretty much exactly what I would have gotten without the filter. Ah, well.
(I may yet still try to salvage the idea of a composite, but it would take more time than I had to get the results to Jerry.)
I suppose I should add: the just-the-Sun shot was f/5.6 @ 1/4000s @ ISO 400; the skyline shot was f/4 @ 1/15s @ ISO 1600. The just-the-Sun shot has no artistic post-processing and is as close to an accurate reproduction as I can get with my equipment as is possible (think fine art giclée copy work) while the skyline shot has a fair amount of post-processing to compress the tonal range into something that looks somewhat pretty.
Cheers,
b&
Nice details, Ben. Makes me want to check out that 400mm lens now 😀 (I’m also thinking of keeping my 7D body instead of selling it to offset the 5D3 cost, as I promised my wife…)
I was wondering how you managed focusing. Using the 10x LiveView, the image jumps all over the place (my tripod is a 25-year-old German one, maybe past its prime…) and what with that and the bright reflection of my shirt in the LCD (even after I fitted a sun-blocking card around the lens) I found it really hard to see if I’d achieved the best focus (though from the results I’d say I wasn’t far off). Weirdly, half pressing the shutter button didn’t seem to engage the stabilization, which it definitely did last year when I took these pics of the moon and Jupiter:
http://pcockerell.zenfolio.com/p579672816
That helped enormously trying to focus!
One scary moment was when I was taking the last shot at about 6:30PDT: the sunblock card (about 18″ square) was a very efficient wind catcher, and a sudden gust ripped the camera away from the tripod’s quick-release mount. $6K of camera and lens started falling 5ft to the sidewalk outside my house, stopped only by my quickly grabbing the strap. Heart-stopping stuff!
Thanks!
The 400 sure is a fun toy, but you’d have to sell more than just the 7D to pay for it…but I’d hang on to the 7D for a while. It’s a good companion to the 5DIII — slightly faster framerate and higher pixel density, albeit a bit noisier and you lose a lot of field of view at the wide end. It’s a good compromise for what it’s intended to do.
The stabilization worked great on the lens. Autofocus, even in live view, was a joke, so I used manual focus at 10X, using Venus to gauge sharpness. Even a fraction of a nudge of the (huge) focus ring was enough to throw off focus.
It was pretty windy out here, too — but nothing close to enough to knock over the tripod! Heart-stopping, indeed. (I use the Manfrotto 055X and its predecessor. I haven’t seen the point of the carbon ones, and these are solid, sturdy, and versatile. I’ll either use a Really Right Stuff ballhead for most things or the Wimberly gimbal head for the 400.)
The wind would occasionally die down for a second or two, during which moments I’d take a shot or two. There was definitely turbulence in the atmosphere causing some distortions, too.
Nice Jupiter picture! It hadn’t occurred to me to use the 400 for Jupiter…but seeing your shot has inspired me. I’ll have to do Saturn, too.
b&
Wow, that’s serious money for the 400mm, and I’m not even sure my tripod could hold it up! I think a more sturdy tripod is next on my list, so thanks for the references. And a 300mm f/4L is more within my budget, but maybe it’s not enough of an extension on the 70-200, given the amount of use it would probably get (not really needed for baby pics :D)
There’s a guy at work who’s interested in my 7D and two decent EF-S lenses, but I think you’re right; I was really happy with it for the 2.5 years I had it (see my Zenfolio albums before April this year) and it would make a great second body.
I definitely need to debug my stabilization problems. When I try it off the tripod, even with the 2x adapter, it’s fine!
Yeah…it took a while to save up for the 400….
The 300 f/4 is a great lens. If you need a moderate telephoto that’s easy to hold and you’ve generally got not-bad light, it’s the one to go for. It’s a great zoo lens, and probably perfect for youth sports. It’s less than ideal for wildlife, but its light weight and small size can easily tip the scales if you’ve got to go backpacking to get to the wildlife.
The stabilization on some lenses get confused when they’re mounted to a tripod. The 70-200, if I remember right, was one of the first lenses to get IS, so chances are good that it’s one of those. Check the manual (which you might be able to find online easier than in a filing cabinet somewhere). It might also have a “tripod-friendly” mode setting. Canon has since done away with all that bother, mostly by making the IS more intelligent. The 400 has four settings: off, normal, panning, and only-apply-IS-during-exposure.
The other good thing about the Manfrotto tripod I didn’t mention is that it’s pretty cheap. It’s a very old design that’s proven itself over the years; the only real compromise you’ll be making over a $1000+ carbon fiber tripod is the weight, and then we’re only talking a pound or so. Plus, the Manfrotto works great as a put-the-camera-to-the-ground macro tripod.
b&
(I just noticed…I had tried to frame the iPhone shot so that the Sun would be visible in the viewfinder as well as on the LCD display. It didn’t look like it came out when I looked at the picture on the iPhone, but you actually can see the circle of the Sun in the optical viewfinder. b&)
Wow. I thought the skyline shot was fantastic, but then I scrolled down and found NASA had wiped the floor with it. Astonishing.
I know. Stupid NASA and their high resolution multi-spectral orbital solar observational satellites!
b&
Well, so when are you getting one, Ben?
UPS says it’ll be here day after tomorrow….
b&
Corny suggestion as a title for your skyline image: Apollo and Venus dancing on the wings of Phoenix.
The best I got with my old 300mm telephoto on my RebelXT with a hi-tech solar filter made up of an eclipse filter roughly cut into a circle and then taped onto the lens was a somewhat blurred and jittery image of the transit, though I did get the three most prominent sun-spots. Your iPhone shot of the back of your camera was still clearer though 🙂
I will…ah…take your suggestion under advisement….
b&
Ben:
Your images are very nice. I really liked your iPhone shot of the LCD screen… I felt like I was there! Loved-loved-loved the cityscape too.
Now — NASA has a solar group and they were all over this event (as well they should be & they did – not – disappoint).
When I saw their picts and that music video, I had to send the link along to Jerry. But, I really liked your stuff and your comments on equipment.
Tom
Thanks! If I have to be upstaged, it might as well be by a multibillion-dollar government agency….
b&
This transit of Venus surely signifies the final passing of love, sex, and beauty from our fallen world.
Here, in fact, is the scientific evidence you atheist heathens have been so snidely demanding. It proves everything will come to an end, as predicted, on December 21, 2012.
Repent, sinners!
Gee, I sure hope you’re joking, but I don’t see a smiley face…
The smiley face is yet another sign our world is coming to an end. Heathen.
Apparently it is very easy to just pass a law that says that the world is not allowed to come to an end. Punishable by fine and/or imprisonment.
Heathen, GOD’S LAW trumps man’s…..
Oh, the hell with it. If I keep this up I’m gonna lose IQ points, and I don’t have any to spare.
😉
😉
😉
I’m still laughing over that smiley face comment. Too true.
Thank you Pete & Ben. Great work!
Great photos Pete and Ben! You both have some serious equipment, and know how.
I had my 90mm Maksutov-Cassegrain telescope set up, hoping to capture some images from the scope with my little Nikon S100. After much planning and setup time . . . . we had solid cloud cover all day long.
Thanks! I just think it’s astonishing what you can capture with what is essentially standard (albeit high-ish end) camera equipment these days. It’s a testament to what modern lenses and sensors are capable of.
I’m sure you would have gotten some great pics with your telescope if the weather had cooperated. In spite of scattered clouds, I was lucky right up until about the midpoint of the transit, when large cirrus clouds started to spoil the view.
Thanks!
…you might be a good person to ask. Would I be right in thinking that it would take silly amounts of money to either get an Hα filter for a camera lens or to get a dedicated Hα telescope that plays nice with a camera?
I got my first (and so far only) taste of Hα the day before the eclipse….
Cheers,
b&
Ben:
I’ve been, and so might you be, surprised at what you can do nowadays with a RAW image taken into Photoshop. It’s no longer just a “brightness-contrast” thingamabob that deteriorates your image.
On the other hand, camera attachments to a good spotting scope (my world for raptor imaging) or a telescope is dicey business ($$, etc). So Pete Cockerell can chime in here.
Tom
Oh, believe me — there’s an awful lot of RAW processing going on in just that skyline shot above. The Sun originally was mostly blown out (and there’s still a fair amount of single-channel overexposure) and the sky was almost as black as the buildings.
But what the Hα filter does isn’t something you can do in RAW…it’s a very narrow-band filter that only passes light with a wavelength of 656.28 nm. That’s the light that gets emitted when the electron in a hydrogen atom falls from its third to its second lowest energy level. It “just so happens” that using such a filter lets you see pretty much everything that happens in the solar atmosphere…all the storms, prominences, filaments, the works.
…and, as I’ve been led to believe, there’s no cheap way to set up that kind of a filter on a camera lens….
b&
Absolutely. I shoot only in RAW and use the full processing goodness of Lightroom 4 to make the most of the exposure latitude it gives you. I’m also rather partial to LR’s noise reduction too, given the high ISOs that I’m often using during concert shoots.
For the Venus photos I used mainly Exposure and Highlights to get the images looking consistent brightness (since I was playing around with f-stops) and a hint of Contrast and Clarity to try to bring out the sunspots. I didn’t change the color balance from “as shot”.
I am no expert, but here is a few bits I know. You can set a camera up for Hα imaging, but how difficult that is depends on the camera. If your camera accepts filters in front of the body, it will be easier to find a filter of the right size as opposed to a filter in front of the lens. Depending on the camera you might have to get more creative, for example building a light box to attach to the lens. A telescope dew guard of the appropriate size might be a good place to start with something like that.
Prices for filters range from about $300 to $800. You could get a decent telescope in that price range, but you would still need a filter. But hey, then you could get into astrophotography. These days you can get decent self tracking scopes, with reasonably good drives for $600 to $1000.
You give me an interesting thought…the 400 takes drop-in filters, and that’s the last element before the lens mount. There may be hope yet!
But I didn’t know that an entire scope worth using for astrophotography can be bought for that kind of money. Will it project a full image onto a full-frame DSLR? What kind of angular field of view will it have? And how close will the sharpness come to matching the resolution of the camera?
Thanks!
b&
Sorry for leaving, had to help the kids make some watermelon pineapple popsicles.
Well, giving it a little more thought I think I was a bit overoptimistic. Considering the equipment you have, the knowledge and skill you’ve displayed a telescope set up for your level would be a bit more. For one, for serious work the mount is as important than the scope, no exaggeration. If you ever need to take longer than 30 second exposures, common for deep sky objects, you need a top quality mount, and those cost of course.
Angular field of view varies widely between optical types. There are numerous configurations for attaching a camera to a telescope, which can affect field of view. You can use eye pieces to vary the field of view, with the proper adapters and what not, but tanstaafl. Other things may suffer, like resolution.
A good quality refractor in the 4″ range can achieve a stellar resolution in the 1 arc second range, which is pretty close to what is possible due to atmospheric seeing.
Considering ease of use, ease of maintenance and optical properties a refractor is the best bet for general astrophotography. With the proviso that you spring for one with apochromatic lenses. Refractors also have relatively fast focal ratios compared to other optical types.
For a very good apochromatic refractor in the 80mm range, about $800. For a slicker than owl shit one in that size range, about $3000. To jump up to the 100mm range, probably more to your taste, your looking at $1500, for very good to $4500 for tops.
A good place to start looking is here.
Wow…that’s some good advice, and that page i excellent. Thanks!
I’m thinking that I should start with what I have, especially considering that the 400 f/2.8 is already an apochromatic 143mm / 5½ refractor. I’ll shelve the idea of Hα for a while and concentrate instead on full-spectrum stuff. I’m already toying with the idea of going back to the Grand Canyon later this year to photograph the Milky Way…I suppose there’s no reason I can’t take the 400 with me and see what it’ll do with Andromeda.
(Deep sky stuff like that is usually stacked exposures, right? Assuming I can find Andromeda in the viewfinder, I should be able to get away with exposures short enough to not streak…the inter-frame motion won’t be a problem, so long as it doesn’t drift too far from the edge of the frame — Photoshop can auto-align the frames. And the 5DIII does great at high ISOs….)
Thanks again!
b&
No sweat, thank you.
143mm aperture? Holy shit! You already have a telescope. I’m not real familiar with those sorts of lenses. Had no idea it was that large. Only thing you are lacking a bit with respect to a telescope, and assuming astro, is focal length.
Stacked exposures are definitely common, but when light is real sparse there is no substitute for long exposure time. If there is not enough light gathered in any of a series of images to stimulate a given pixel, stacking the images won’t give you anything. But a several minute exposure will. Think Hubble deep field for an extreme example. Stacking works great for a composite of different wave length images too, which each hilight different features not well seen, or not seen at all, in the other wavelengths. But to do that you need a set of good filters.
If you get the Milky Way over the Grand Canyon, PLEASE make Jerry post some images.
Well, 400 / 2.8 = 143…so, yeah.
If the math I just did is right, then 400mm is just about right for all of Andromeda plus just a little bit extra for framing. I know the really deep stuff is smaller, but I’ve got both the 1.4x and 2x teleconverters, which turn it into a 560mm f/4 and 800 f/5.6 respectively. (You can stack the two, making it an 1120 f/8, but the image quality hit is bad enough with the 2x that you might be better off just interpolating in Photoshop than stacking.)
But…if I leave out the teleconverters, I’m still left with an f/2.8 lens. The page here:
http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/m31-500mm-8780-8825-av46_RJ.v5-600.html
says he stacked 46 exposures, each being 60s @ f/4 @ ISO 400. At f/2.8 and ISO 25,600, that’s only a half a second for the same exposure…any chance that’s fast enough to not need a tracking mount? If so, I can just manually re-align the camera between exposures (and be prepared to crop away the outer edges where the overlap doesn’t match up). Sure, it’d be a bit on the noisy side, but probably not much more than the 10D he used — and isn’t that part of what stacking is supposed to help with? And you can take an awful lot of half-second exposures over the course of an hour…almost a thousand, if you have the camera do the dark-frame noise reduction for you.
And, rest assured: if / when I shoot the Milky Way over the Canyon, I will absolutely inflict the results upon Jerry.
Thanks again!
b&
Watch the clip 32 seconds in. YOu can see the edge of the sun through Venus. Why? Is this fake like the moon landing?
First, if you don’t think the Apollo program was real, then you belong in the psychiatric ward of a hospital. I’ll therefore assume for the moment that that last sentence is snark.
I have no clue what sort of equipment NASA is using there, but I’ve often seen similar effects with my own DSLRs. Indeed, you can even see it in my own photo at the top of the page of the Sun setting behind a skyscraper. I’m no engineer, but I’d suggest it’s a form of overexposure overload, possibly enhanced by lens flare.
Remember — these aren’t merely shots into the Sun, and not even shots with the Sun in the frame, but actually shots of the Sun. That goes beyond mere torture tests of optics straight into the Hellfire and Brimstone realm. With only a very few exceptions, lenses are an insane mess of lens flare artifacts in these situations. And sensors? The Sun isn’t merely beyond the published specifications of what the sensor is capable of imaging, it’s well into the range of, “Doing this carries a high risk of irreparable physical damage that will not be covered by your warranty.”
b&