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An Accidental Mosaic: Sagittarius & Ophiuchus with Saturn

astrophotography dslr dso tripod planet star party


Alen Koebel

An Accidental Mosaic: Sagittarius & Ophiuchus with Saturn

This panoramic mosaic was stitched together from a total of seven overlapping images using Microsoft's Image Composite Editor (ICE). Each image is a 60-second exposure @ ISO 1600 taken through a 200mm f/4 SMC Pentax-M lens @ f/5.6 using a Pentax K-3II DSLR on a tripod. The camera's Astrotracer feature allows it to track the stars without needing an external tracker or equatorial mount. This image is an accidental mosaic because I did not plan it. I just happened to take overlapping shots around that area in the course of evaluating the Astrotracer feature on my first night of using it. On the left side of the image is the globular cluster M22. Southwest of it is the much smaller globular M28. Saturn shines brightly near the middle of the frame, with open cluster M21, the Trifid Nebula M20 and the Lagoon Nebula M8 in an arc to the right of Saturn heading south. The large open cluster M23 is northwest of Saturn some distance away. Numerous dark nebulae are visible. The mosaic's original size is over 16,000 pixels across. Unfortunately, this upload is at the maximum 1,600 pixels across allowed by CN. Despite some sharpening to make small features more visible after the resizing, it has lost most of the original's details and stars look woefully under-sampled. Note that this mosaic was constructed from the in-camera JPEGs as a test. I will replace with a better version from the RAW files at a later date. Taken August 10, 2018 at the Starfest star party near Mount Forest, Ontario.

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