I was able to escape from the Bay area light dome and spent two weeks in Abiquiu, NM, where I used extensively the Astrotrac Travel System with a set of good Canon teleobjectives and my Takahashi fs60-c.
I’ll post most of the pictures I took – but I was very satisfied with the performance of the Astrotrac for unguided wide field photography.
Photographies were taken either with a modified Canon XTi, or with a Qhy8 CCD coupled to the Teleobjectives.
Here is NGC 7000 and the Pelican Nebulae with the Canon 200mm f/d 2.8 L Teleobjective and the Qhy8 CCD camera.
It is a combination of 27 exposures of 2 minutes, processed with Dark, biais, and Flat frames.
When coupled with the CCD it is not possible to control the F/D ratio of the Teleobjective, but at f/d 2.8 the lens performance is still honorable and shows sharp stars.
I was able to observe the Qhy8 does a slightly better job in capturing faint details of the nebulae. I suspect it is due to the pixel size of the Qhy8 sensor (7.8 microns). This is about 50% larger in area compared to the Canon XTi sensor, and captures in theory 50% more photons by pixel in the same exposure time for extended objects like nebulae.
Below is the cropped image showing details of the Anerica and Pelican Nebulae. As you can see the image is still full of details when magnified.
Combining 27 frames contributes a lot in increasing the signal/noise ratio. Focus has been done using the real time view of the CCD, and here again advantage for the Qhy8 compared with the Canon XTi. Focus is done by looking in real time at the Full Width Half Maximum measurement on a bright star – and allows a very precise focusing – which is not a small feat at f/d 2.8.