NGC 7000

NGC7000 has always been a favorite target of mine and I’ve imaged it and the Pelican several times. I’ve got widefield images and telescopic shots but I’ve always wanted to take a telescopic shot of the whole North American and Pelican complex. My problem has always been that the field of view through my scopes was too small and even my Rokinon lenses had too short a focal length to give great detail. For the last several months I’ve been working on a solution, Mosaic Engine is a software package that controls any ASCOM compatible telescope mount to take wide mosaics of my favorite objects. On 7 July I got out to my favorite dark sky site for a test of the system. My plan was to shoot a 3 by 3 frame mosaic, but the Moon rose before I could finish so I still have three more frames to shoot. So far I’m very pleased with the result.

So far the mosaic consists of six frames, each one being a 30 minute stack of five minute subs. The image was captured on a night of very good transparency but only so-so seeing.

My software setup used Mosaic Engine to control the scope, PHD2 guiding software to accurately guide allowing Back Yard EOS to acquire the data from my Canon 60Da. I also use Earth Centered Universe (ECU) to provide scope control and show the position of the scope on the sky. ECU is a great planetarium program that focuses on what observers actually need and less on glitz. AstroTortilla provides precise positioning of the mount and measures the rotation of the camera (required by Mosaic Engine). Mosaic Engine calculates the center position of each frame in the mosaic and executes a goto to move the scope for each frame. It also interfaces with PHD to stop guiding before each goto and to reacquire a guide star after the goto completes.

The image was captured using a SkyWatcher Esprit 120 APO which produces pinpoint stars to the corner of the frame making it easy to assemble the final mosaic. The image was assembled using Microsoft’s Image Composition Editor (ICE), simply the best mosaic and panorama software I’ve used to date. Once the target is centered, Mosaic Engine acts as the central control hub handling the mount motions and controlling PHD to acquire guide stars for each frame.

Using ECU I was able to verify the position of each frame. This allowed me to check on the progress of the mosaic as Mosaic Engine stepped through the entire mosaic. Stay tuned, with summer vacation approaching I’m planning on finishing the mosaic and starting one of M31.


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