The Photo that Took 1½ Years to Take
Sometimes photos take a little longer. I first saw an image of the chapel at the Wankerfleck (yeah, yeah, I know, stop giggling) a couple of years ago and thought to myself 'wow, that looks cool, I'd love to get there - where is it?', and was promptly blown away to discover that it's actually quite close to me. I've lived here for twenty years. How have I not heard of this place? So in March 2022 - on my birthday to be precise, we took a hike up the long road from Halblech and got a first look in person.
Three months later I went back on a solo tour to check out the location a bit more. I'm not entirely sure when it occurred to me that this would be a really cool foreground for a Milky Way, especially with the imposing Geiselstein in the background.
Taking the Photo(s)
The final image was actually a composite of two images. There are three main reasons for this for any astro image. Firstly, there is insufficient light for the foreground image when the Milky Way is showing; it's only possible to get a good astro image starting around 2 h after sunset - before that there's simply too much light in the sky. Secondly, due to the wide open aperture needed to capture starlight, there would be insufficient depth of field to capture the foreground in an acceptably sharp manor. Thirdly, in order to maximise the quality of my astro images I use a star tracker instead of stacking my images. This device rotates the camera slowly in parallel to the earth's rotation, ensuring that the stars remain sharp instead of streaking in the sky as can be seen from this 180 s image - a close up of the final foreground shot.
Although the foreground and sky images were taken approximately 100 m apart, I did take care to make sure that the images would line up using the Geiselstein as a fixed point for reasons of authenticity as much as anything else.
I took a great deal of care when positioning the tripod to get a good composition with the chapel and the road to the right, giving enough room at the bottom for the image to breath whilst allowing enough space at the top of the image for, well, space. We then double-checked that the Milky Way was going to be where we expected it using the smartphone PhotoPills app. If you haven't got PhotoPills, use a free website such as Stellarium-web.org to plan the shoot ahead of time and use a compass in the field to set the image up. Although the Galactic Core is still visible above the horizon at the end of August, we knew that we wouldn't be seeing it due to the steep sided valley that we were in.
A good astro image doesn't need to be all about the sky, in fact as you can see here, only about 50% of the image is going to be stars. A good astro image lives or dies by the foreground, provided you have clear skies. When I envisioned the image I saw in my mind's eye light coming out of the chapel and I brought a couple of tea-lights - miniature candles.
The starry sky image was taken 100 m behind the chapel in an open field between cloud banks. There were two reasons for the alternative location. Firstly, tracking requires being able to sight the star tracker on Polaris. After setting up the camera I realised that my view of Polaris was blocked by a huge stand of fir trees right behind me. Secondly, it allowed a cleaner horizon avoiding the fir trees in the foreground.
Tips in the Field
I took my first astro images back in 2020. I'm no expert, although I feel with this image that I've learned enough from my mistakes to be able to speak with some authority.
Arrive early and take your foreground images in good time. Don't be afraid to keep taking the same image every 5-15 min or so as the light changes.
If you're using a star tracker, level your tripod, especially if you either haven't got a clear bead on Polaris or are intending to shoot a panorama.
Try to decide on a single composition and stick with it rather than taking several images to hedge your bets.
If you have a smartphone with the PhotoPills app, double-check that the Milky Way is going to be in the right place for your composition using Night AR mode.
Once you've achieved focus, shoot a couple of test images at ultra-high ISO to make sure the stars are sharp.
Dim your camera display as much as possible and base the exposure on the histogram rather than relying on your (dark-adapted) eyes - they will deceive you into thinking that the image is brighter than it is.
Rely on your in-camera histogram rather than your eyes in the field for a correct exposure. The main column of exposure should be about a third of the way into the graph and there should be a gap to the left of the exposure diagram, otherwise you are losing data.
Equipment & Technical Details
Panasonic Leica f/2.8-4 8-18 mm
Benro GC3WH Geared Head
MSM start tracker
Kase Alyn Wallace Starglow filter*
*enhances the glow and colour of the brighter stars in the image
I use OM-System (Olympus) cameras due to their portability and technical capability. It's not a system that I would have chosen if my photography was predominantly astro, but it's a system that works well for me.
9 mm, ISO 800, 180 s, f/8
9 mm, ISO 800, 240 s, f/3.1*
*exposure performed using the MSM Star Tracker and the Kase Alyn Wallace Starglow filter for 25% of the exposure time (simply held the filter in front of the lens for the first 60 s of the exposure, taking care to avoid reflections from the red lights on the MSM control panel.
I shoot my astro images using Starry AF mode with the OM-1 in Live Time mode with the interval set to 30 s, histogram showing, Night Vision mode on, White Balance custom set to 3800 K and Noise Reduction off. The display should be set to minimum brightness. I use a remote shutter.
Processing the Photos
Here are my two base photos that I now needed to merge together in ON1 Photo Raw in order to arrive at the final image. Notice that in the foreground image the stars are trailing, whilst in the sky image the mountain peak is blurred.
So how do you bring these two photos together into one cohesive image?
Tracking vs. Stacking:
The biggest issue with astrophotography is getting enough light. The amount of light in the image is limited by three factors; (1) ISO, (2) exposure time and (3) aperture, all of which have disadvantages.
(1) ISO increases the ISO of the camera can negatively affect the image in two ways; it increases the amount of noise in the image and reduces the colour range in the image.
(2) If you want pin-sharp stars rather than lines (see 3 min image above) exposure is limited by the focal length of your lens - the maximum exposure without a tracker is (500/[focal length]) s - with a 50 mm lens, for example, the maximal exposure would be 500/50 = 10 s.
(3) Aperture can affect the image quality (look up coma and chromatic aberration).
Basically, you want to keep ISO as close to the camera's native ISO - usually around 100-200, make the exposure as long as possible and make the aperture as wide as possible (lowest f/number possible) without causing optical problems.
One way of reducing ISO noise in an image is by stacking the images - taking multiple images and averaging them out using software (Sequator) - noise is a random phenomenon and can be overcome by averaging.
Alternatively, the (500/[focal length]) limit can be overcome by rotating the camera at the same rate as the earth is turning using a star tracker. Apart from necessitating additional equipment, the other downside to tracking is that additional processing steps are necessary to bring the foreground and sky together in one image.
The first step is to do a basic edit on the two images. I've adjusted the colour temperature and exposure, increased the contrast a little.
The two images are then loaded as separate layers into a single image. Only problem is that the mountain is more central in the sky image, leaving empty sky:
My solution was to cheat; I duplicated the sky layer, rotated it 180°, twisted a bit and arrived at this:
The last steps were to clean up the border between the foreground and sky, darken the background mountain, desaturate the light in the chapel as well as boost the overall exposure and adjust micro-contrast in selected areas to arrive at the final image.
I really feel that it's all come together at this point. Apart from one nagging detail, everything has finally come together from conceptualisation to execution. I think one of my favourite feedbacks that I've received about this image so far is from a photographer friend whom I look up to who had to ask whether it was a single image or not, indicating that the blending process between the two images was on point (even if he was only checking on a smartphone). The nagging detail? The only thing that I would change is that I would open the left-hand door 45° to invite the viewer in.