I bought a new lens recently: a Canon 100mm f/2.8 Macro USM. It's a highly recommended 1:1 macro lens I wanted it to digitize my slide collection, which is a long term project unrelated to astrophotography.
However I thought I'd try it out for astrophotography. So in the early hours of Sunday morning there was a break in the clouds and I attached it to the full frame modified Sony A7S and collected nearly 2 hours of data:
(http://www.markshelley.co.uk/Astronomy/2019/cygnus100mm_20190504_small.jpg)
Here's the full size version:
http://www.markshelley.co.uk/Astronomy/2019/cygnus100mm_20190504.jpg
Considering I used this wide open, it's not a bad result as long as you don't look too closely. The reason for going wide open was to get an image as deep as possible to form a good reference for the 6x6 panel Cygnus mosaic I shot in France last year. Processing the mosaic has been a nightmare. AstroPixelProcessor did a perfect job of aligning all the pieces but removing the background gradients and selecting the black point for each panel is actually a very hard problem.
Here's a preview of the output from APP after white balance, camera correction matrix and gamma have been applied:
(http://www.markshelley.co.uk/Astronomy/2019/cynus_mosiac_early_draft.jpg)
It actually did an excellent job of blending the pieces together but the black points of the various panes are not quite correct because there are no areas of pure background sky - the Milky Way is simply too full of stars!
So it's a work in progress - a medium term project. But at least I have a halfway reasonable reference image to compare against. It's a happy coincidence that the field of view from the 100mm lens is pretty close to the mosaic FOV. It's almost impossible to find an image of this area on the internet which has correct colour and correct black point.
Mark
The image is looking stunning Mark. Having seen the National Geographic 'Take the Mickly Way' they found acceptable I wouldn't worry too much about the really twiddly fiddles. But I know your OCD about these things!
But confused as to what the top image represents, as it seems to have a larger FOV to the bottom mosaic-ed image.
However I much prefer the mosaic-ed bottom image as it has better contrast, star colour and detail and the individual nebulae stand out much better.
Or is the top one the one you did in France??
Carole
Quote from: Carole on May 10, 2019, 15:44:57
But confused as to what the top image represents, as it seems to have a larger FOV to the bottom mosaic-ed image.
However I much prefer the mosaic-ed bottom image as it has better contrast, star colour and detail and the individual nebulae stand out much better.
Or is the top one the one you did in France??
Carole
The top one was taken with a 100mm focal length lens this week.
The bottom mosaic was taken in France last year using the Tak Epsilon (500mm focal length). It will be a huge image when finally processed. Hopefully a true pièce de résistance.
Mark
Great image Mark. When you click on the link and then enlarge it, the star field is amazing!
Hugh
Yes - an amzing star field!
A very interesting piece of work Mark.
Noel
Superb image Mark! Can't wait for the final version of the original mosaic or what you will be able to do with the lens in the future.
Roberto