Quote:
Originally Posted by irwjager
Looking good Martin and congrats on the NexDome! I'm happy to hear you are all getting along with ST 1.7. 
I can't quite place Andy's comment though about the halos in this particular image; the stars are very well resolved to their - presumably overexposed - cores (as far as I can tell of course). Some operation may mildly accentuate them if no (or an unsuitable) mask is used, but they are nevertheless real, important features of your dataset.
Stars should readily show their diffraction patterns and definitely not look like blown out fuzzy blobs, smudges or featureless discs. Their over-exposed cores should not grow or bleed into neighbouring pixels when being stretched from their linear state and should always be well defined. Just like black clipping is a no-no to many of our peers, so is white clipping.
Diffraction patterns serve a few purposes to the viewer and person processing the data;
They serve as a good indicator as to what instrument was used, they serve as color balancing tool and star temperature indicator (in case of a visual spectrum dataset), they serve as a deconvolution calibration target and they serve as a proof/authentication of detail fidelity. The latter two are because they always constitute high SNR areas in your image (even in poor SNR datasets!). This makes it easy for deconvolution to do its thing and thus provide an ideal target to gauge how well the algorithm is doing. And due to to the intricacies of their patterns, they show up any artifacts much easier as well, giving a more experienced viewer a good idea of how an image was processed and where it might fall on the astro "art" vs documentary astrpphotography continuum if that is a concern.
Lastly, to get StarTools to launch on later versions of macOS, you may have to "unquarantine" the application ( simple instructions with screenshots here). Any license will allow you to evaluate 1.7 in full if that is of interest. Any trouble, do let me know! |
Ivo,
Thanks for your kind comment regarding my image
Looking forward to capturing some decent images in the Dome later this month and putting ST 1.7 through its paces , it’s certainly been a struggle with the weather of late ( mostly east coast of the Continent to the great divide )
Hopefully Andy reads your post regarding using Startools 1.7 on a Mac
Cheers
Martin