Finally, a night where… A) The sky is clear. B) The wind is not howling through the palm trees. C) I am not exhausted by working the summit. D) I do not have to get up early the next morning.
A + B + C + D = Astrophotography from the driveway!
Comet C/2009 P1 Garradd on 29 March 2012 showing both tails, sum of 50 x 1 min exposures CoolSNAP ES and 180mm f/2.8 lensThus, under a very pretty sky, I rolled the photo rig out of the garage and spent some time getting everything back together. I was not in a hurry, time to let a bright crescent Moon set a little and my primary target rise a little. The target at the top of the list? Comet C/2009 P1 Garradd.
The comet is nicely placed in Ursa Major, transiting late in the evening, available for several hours of exposures. And expose I did, with the auto-guider locked on the a dim star beside the comet, the shutter open for well over two hours. I was shooting my Canon 20Da and the AT6RC, a combination that framed the comet nicely.
It will take a while to get the resulting images processed. In the meantime I did a quick process on a set of images taken with the wide field/finder CCD camera. The results of which can be seen at the right. I also shot a few quick images of the M95 area with the CCD to capture SN2012aw.
When doing any sort of public astronomy, showing folks the beautiful sights available to a telescope, I often hear the question “Can I take a photo of that?” The person asking the question is usually holding the ubiquitous compact digital camera. They are often surprised when my answer is “Yes”.
Taking a photograph of the Moon using afocal photography
It is indeed possible to manage hand held shots of bright astronomical objects by simply holding the camera up to the eyepiece. There are a few tricks to making it work, but nothing that can not be demonstrated in a minute or two. The resulting photographs can be quite pleasing, definitely worth showing to friends and family along with the rest of the Hawai’i vacation shots.
The method of positioning a camera with a lens in front of an eyepiece is called afocal photography, or sometimes digiscoping. Afocal has been around for a while, but was not considered a practical photographic method by most. The advent of common digital cameras without removable lenses has changed this.
I have been getting a few questions about the video. To answer a few of them I have compiled a guide to the scenes. Some quick explanations to what you are seeing, information on the camera used as well as the exposure information.
The video is a combination of two techniques. Many scenes were filmed as standard video then accelerated during editing to allow the motion to become clear. Examples of this are scenes of telescopes slewing and the interferometer delay lines moving.
Slower subjects, such as clouds or the stars moving across the sky, were photographed as time lapse. Here a large number of still images were taken. These are then processed and converted to video using Photoshop CS5 before loading into the video editing software, Adobe Premiere Elements. To construct the time lapse sequences sometimes required thousands of separate images, quickly filling memory cards and exhausting batteries. After dark it is long exposure time lapse that is used, with individual exposures often 15 seconds to one minute long.
With four days of observing scheduled starting tonight, the pressure was on. Both Keck telescopes, four nights, lost for something I am responsible for? Not an attractive prospect. Everyone in the department has a helpful hint or two, some of them even made sense, most we had already tried. Phone calls and emails fly as everyone chimes in, even the guys at JPL who built the cameras get involved.
It was not until three in the afternoon that I found it. Comparing oscilloscope traces between the two FATCAT instruments I note something amiss in the video signal. Most of the waveforms makes sense, even look OK if viewed alone. The colored trace on the screen isn’t the same as the working camera. Now I recall a couple other waveforms I had looked at earlier and wondered about, even to the point of making some notes about. Realization dawned with an enormous sense of relief. Those clock edges are not supposed to be rounded like that!
I pull the clock driver board out of the working camera and install it in the problem child… The noise goes away!
I stole a spare clock drive card from the instrument guys, from the spares for LRIS. I suppose I will hear about raiding their precious stash Monday when they find my note.
I need both cameras and two good clock boards. The spare has to be configured correctly, which takes another hour of logic and good guesses in the absence of decent documentation. Only two hours before dark we perform the final checkouts on the system, the mood notably lighter as we realize it is going to work.
As I write this the FATCAT cameras are on-sky, detecting fringes of interfering light from some distant star.
Yes, it is broken. Worse, I do not know how to fix it.
Specifically it is the primary fringe tracking camera, FATCAT, that has unacceptable levels of noise. We are due to be observing with it tomorrow night. No fringe tracker, no interferometer. After several days of troubleshooting I still have no idea what is wrong. I do know about a lot of things that are working, having painstakingly checked many parts of the system. The level of frustration is building.
Back to the summit tomorrow. Which sucks. I was supposed to be helping out with the Planet Walk tomorrow. Setting up a solar telescope to allow kids to see our star. Instead, it is back to the frustration of a broken camera.
A box was waiting for me when I got home. A long awaited box. A box that represented hours of reading, weighing and wrestling with the question…
A new camera!
I now have a replacement for my venerable Canon 20Da that I have used for over six years. Not that I will be getting rid of the older camera. It is still invaluable to me for astrophotography, a role it is specifically modified for. Nor will it replace my Canon G11, a camera I have carried every day for well over a year now. The G11 will remain my day to day camera, a role for which a compact is well suited.
The Canon 60D DSLR camera, image credit: Canon USA
No, the 60D will be there when the smaller camera is simply not enough. There have been a few recent instances when I had opportunity for a good photo. An image I knew the camera in my hand simply could not capture. There was that pueo sitting on a lichen covered boulder last week. Or the summit under a blanket of fresh snow, lit by the full moon. Or… To many instances.
Another primary reason for the 60D… High quality HD video capability. This is something I have come to truly miss in my existing cameras. There have been a number of occasions when I really could have used that capability! Unfortunately now that I have a camera capable of truly good HD video, our backyard volcano has stopped producing photogenic lava flows. At least I know that will not last.
The decision was made more difficult by the choice of cameras available. A dizzying array of options now exist. A number of very capable DLSRs, the new mirrorless designs, this was a decision without a simple answer. In the end it came down to a choice between the Canon 60D and the very similar 7D. The newer 60D sports a flip out screen (something I love to have), better movie controls, and while it gives up a metal body it is also much lighter to carry. Both cameras use the same sensor and feature essentially the same image quality.
My thanks to Baron. I ran into him at the ROV competition last week. And lo… he was carrying both the 60D and a 7D. Even better, he let me fondle his gear while we chatted about the relative merits of the two cameras. Nothing like a hands-on look at the gear and the opinion of someone who uses the cameras extensively.
Even when holding a brand new camera I am wondering what will replace it in a few years. Maybe a mirrorless compact? That is a market segment to watch. What about my veteran G11 camera? Deb is making less than subtle suggestions about my getting a G12 so she can have my G11, mostly for underwater I suspect. Cameras are one place the technology is still changing rapidly enough to make these decisions difficult.
For now I need to learn a new camera and find its limits. A good low light session is in order, and I have a night on the summit coming up… with lasers!
