Constellation Cygnus the Swan – Canon 5DsR + EF 24-70mm f/2.8L II @70mm
I have tried my hand at many a genre of photography but none have humbled me the way astrophotography has. A few weekends ago I happened to be free the same time we had a New Moon. This meant that I could actually have a care-free 24 hours to pack up all my gear and run away somewhere with less light pollution than my backyard. I opted for my good friend Ethan’s place in Auburn. An amazing artist himself, it was refreshing just to catch up with him. Another friend Jeremy came out at the last minute. He’d always wanted to explore Astrophotography so I figured this would be a good opportunity to share what I’ve learned so far.
I stuffed my car full of everything I could think of – my entire telescope and mount setup (read more about that here) as well as my entire photography kit – and headed up the Auburn Hills to Grass Valley. I figured if it turned out to be a good showing, I wanted to be prepared. It was mostly cloudy but the forecast said it should clear up by 10pm, right when the sunset really ends, so I took my chance. Unfortunately the clouds and haze lingered all night especially in the Northern sky where it was darkest. The light pollution from the Sacramento valley was also much worse than anticipated. Combined with the haze it overpowered all but a few of the brightest stars.
Finally around midnight the North Eastern quadrant of the sky cleared up. Due to the weather conditions I was only able to perform a very loose polar alignment as well as a poor 2-star alignment of the Celestron Advanced GT German Equatorial (GE) Mount. This resulted in poor tracking. However poor tracking on a GE mount is always better than a simple tripod. To compensate for this I chose to use the Canon 5D Mark III for its excellent high ISO low noise capabilities. I mounted it (piggy-back) on the telescope and aimed at the clear part of the sky – the Constellation Cygnus. After just a handful of shots I realized that even with the poor alignment, I was still able to do 3 minute (180 second) exposures at ISO-400 without the stars trailing. I knew this was well within the capabilities of the higher pixel density sensor cameras such as the 7D Mark II or even better, the 5DsR. Both just happened to be laying idle in my bag.
I had never tried the 5DsR at astrophotography and very much wanted to see how it performed. I liked how the 7D Mark II did and knew the 5DsR would at least match or exceed it since they have very similar pixel densities. Accounting for about 1 stop exposure difference from the 5D Mark III, I bumped the ISO to 800. Exposure stayed the same at 3 minutes. I was also shooting with the Canon EF 24-70mm f/2.8L II which I recently added to my kit. I knew it was tack sharp and would be able to keep up with the 50 megapixel body. Nothing prepared me for what I saw. I only took 4 shots and decided it was good enough.
What you are looking at above is a single 3 minute exposure. Processed from a RAW file with no noise reduction, some color temperature and curve adjustments and a final light mask to help reduce the atmospheric haze. Nothing fancy not even lens correction (you can see some vignetting). The shot has bee downsized to about 1/12th it’s original size. At 70mm the detail is astounding. The light “clouds” are easily revealed to be individual stars. Mind-boggling scale and detail. It’s one thing to see images from the Hubble telescope, but an entirely different experience to see it for yourself.
I’m not sure what took me so long, but it’s safe to say I will be spending several sleepless nights shooting the stars out in the middle of nowhere this summer.
Sun shot 1 – full resolution
As usual this July 4th weekend we had several fires in the area so the skies have been particularly hazy which definitely does not help for any kind of viewing of celestial objects. However this morning I remembered the one object that would need more than hazy skies to obscure was available for observation: The Sun.
After my DSLR focuser support rail modification the two next items high on my list were an electronic focuser and a solar observation filter for the telescope. Today I decided it was time to put them both to work after installing them late this past week. Getting a shot of the sun is harder to acomplish than I thought. My spotting scope does not have a solar filter so I could not aim the telescope. after trying unsuccessfully for about 15 minutes, I took the cover off the spotting scope and placed the back of my hand behind the eyepiece to see if I could bring the sun within the field of view. Luckily I did not burn my hand but do not try this at home…LOL.
Once in range I fiddled around with the fine adjustments on the mount controller until the sun came into view in the eyepiece. The filter is so dark, you cannot see anything until the sun “magically” appears in view. The electronic focuser is completely indispensable, especially with the heavy DSLR attached. The rail works so well you don’t notice it. It will remain on the telescope permanently (Orion should just make all refractors with a rail). I quickly swapped the 7D back in place of the eyepiece and used live view to fine focus and center the sun. I used a thick dark towel over my head and the camera in order to view the camera screen and get as clear a shot as possible. I will most likely get some kind of solar foil blanket to make this process easier. As a result my focus was not spot on, but good enough for a first run. From that point on it was just a matter of taking multiple shots at various exposures.
The 7D was set to manual, AWB, ISO-100, and shutter speeds ranged from 1/2000 to 1/8000 second. Using the RAW files I was able to see the ripples on the surface. They may look like noise but it’s just the enhanced contrast of the surface ripples (note, noise would show up in the dark area of the shot). If anyone has any ideas or tips on how to better process and filter the RAW files please drop a comment below. I’m new to this stuff and I know there are ways to enhance and extract features that would otherwise go unnoticed.
The entire telescope and camera assembly were starting to bake in the sun. In a rush to take it indoors, I forgot to take a shot with the Canon EF 2X Extender. I will post those next time I get around to it. You can read more interesting facts about the Sun here.
Thanks for stopping by.
Solar observation setup
Solar observation setup
Sun shot 2 – full resolution
Orion SkyView Pro 120mm EQ 1000mm on Celestron Advanced GT German Equatorial Mount.
For quite some time now I have had my heart set on taking the life-long journey into the world of astrophotography. I began studying and researching a few years ago. My initial goal was not to learn all there is to know out there but to simply understand what it would take to successfully photograph DSOs (Deep Space Objects). My whole life I have always read and consumed any media I could find on the subject of astronomy, astrophysics and the science of celestial bodies. Growing up in Cameroon, West Africa, a telescope was definitely a very far fetched fantasy so this is an especially significant experience for me. I had previously never looked through a telescope until about a week ago.
I learned enough over the past year to know that for astrophotography, I would need a really good refractor telescope with an aperture of at least 80mm and more importanly I would need a very good german equatorial mount, ideally with GoTo and tracking capabilities. Then I began researching refractors and found out that I would prefer a triplet or at least an apochromatic refractor or doublet. I also concluded that the focal length of most 80mm refractors (under 500mm) did not justify the expense considering I already had a really good 200mm f/2.8 lens and a 2x extender which when combined with my 7D crop factor gave me an effective focal length which was comparable.
So that left me with only refractor telescopes with an aperture of 120mm or larger. Needless to say I quickly saw the expense climbing beyond the stratosphere. So I started shopping the used market. I recently stumbled upon a gentleman who was selling his complete 120mm Orion refractor setup, complete with Celestron Advanced GT mount and auto guide CCD camera scope as well as an assortment of eyepieces, essential accessories and Canon EOS DSLR adapter.
There is so very much to learn. This is an opportunity for me to gain a firm grasp of the fundamentals of astrophotography and astronomy in general without getting too heavily invested. I was able to see Saturn and it’s rings within minutes of setting it up and a few more minutes later I was able to attach my 7D and snag a few really blurry shots. The weight of the DSLR on the focuser made it impossible to acquire and maintain focus. So the first order of business was to modify the telescope mount to accommodate the added weight and relieve the focuser of the stresses.
You can see photos below of a sliding rail I rigged together with some extra aluminum tubing I had left over from my DIY time lapse track and dolly . This vastly improved stability and focusing in my quick test moon shot. I just ordered an electric focusing motor which should eliminate the residual shake when trying to focus. I’m excited!
Focuser camera support rail and carriage modification.
Telescope next to the Canon EF 70-200mm f/2.8 IS II for size comparison.
Focuser camera rail and carriage.