First Mosaics

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The comparably short focal length of 525mm provided by the Hyperstar is giving a quite big field of view enabling the fast imaging of objects that are simply too big for the optics I was using before. The C9.25 has a focal length of 1480mm with reducer and 2350mm at primary focus. This is good for smaller objects like most galaxies, but most of the objects I showed in the previous posts simply wouldn't fit in one picture. 

I was eager to take picture of all the big objects that I always took off the list before. However, as it turns out, there are still a number of "famous" objects that won't fit in a single image even with the Hyperstar. So, I did bite the bullet and started composing mosaics of multiple images. It turns out that this works quite well, even though the required exposure times grow quite fast with the number of mosaic panels.

Here is a first 2x2 mosaic I did of the North America and Pelican Nebula. Each subimage is an integration of 200 frames.


My second mosaic - the Veil Nebula - is using a 2x2 pattern as well. However, I "cheated" a bit with the exposure times. The bottom left panel, that has only stars and no nebulosity, is only integrating 20 frames, while for the other panels I took 200 frames. In addition I included the images of the eastern and western veil nebula I took earlier for the "first light" post. So the number of frames actually ranges from 20 to 400 depending on region. This approach makes it a bit harder to get an even background, but is saving a lot of time and making best use of the available data.



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