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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 mosaic was stitched together from a total of seven overlapping photos using Microsoft's Image Composite Editor (ICE). The camera was mounted only on a tripod; tracking was provided internally using the camera's Astrotracer feature. This image is accidental 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 is the globular cluster M22. Southwest of it is the 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 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.

_Imager: Pentax K-3II DSLR (APS-C). _Lens: SMC Pentax-M 200mm f/4 @ f/5.6 _Exposure: 60 seconds x 7 panels @ ISO 1600. _Tracking: Astrotracer (built in) _Date: August 10, 2018. _Location: Near Ayton, Ontario, Canada. _Sky Conditions: Bortle 3, good transparency.

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