Quote:
Originally Posted by alpal
Hi Roger,
A great result to image so many galaxies in a short space of time.
Now - you can choose which one to spend more time on?
I am surprised that you didn't go for the longer focal length to try
& get more detail from such small targets.
cheers
Allan
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Yes, quite a few
A few years ago I did my Project NGC (
more info here) in part to have a good overall coverage from which to choose objects to focus on. Turns out I just like taking more images the same than focusing on particular objects so much
Anyway, this time I'm aiming for higher quality and more complete coverage of galaxies in particular.
My Project NGC images were 10x30s (back in the days of my fork mount and it's limitations), where as these new ones are 5x180s, so are much deeper images and overall better. Also the old ones were with the ST7 and new with the ST8 so I have a wider FOV but exact same pixel scale, to get larger objects more easily.
Regarding focal length - I'm at 0.86"/pixel. I find that to get a sharp image at smaller than that needs significant data, good viewing conditions, probably a better optical tube than I have, and ideally a mountain top.
Over the last few years I've become convinced that anything smaller than ~0.86"/pixel is simply undesirable at sea level type normal locations like Perth and if I were to buy a new telescope I'd be making sure the focal length doesn't exceed that pixel scale with camera taken in to account, I think it just becomes a waste and you may as well take advantage of a better focal ratio permitting shorter exposure times/more light.