I have finally found time to process this 4-plane mosaic of the region between Cygnus and Aquila. Coincidentally it can be considered my aniversary photo because I bought my Pentax 6x7 nearly exactly 10 years ago.
The shots were taken in 2018. The sky was covered by thin clouds nearly the whole season. This is why the stars are a bit hazy. Each plane was exposed for 40 min at f/4. The lens was Takumar 105mm and film Kodak E200. I used my homemade vacuum back to hold the film flat. The mount was aligned with the PARot program. The processing was the most difficult part. First I removed the vignetting and background gradients from each individual frame. I did it manually in Photoshop by selecting the dimmer/brighter areas and adjusting the levels. Increasing the contrast temporarily by an adjustment layer alowed me to make the corrections exactly. The mosaic was assembled in Photoshop again, using the photomerge function. This unfortunatelly doesn't leave a completely seamless result. After cropping the image there were some empty areas near the corners of the image. I had to fill them using the Content Aware Fill function. If you compare carefully the image with others, you can note that some stars don't match.