The Drizzle, an algorithm designed for Deep Space

This feature is present in the main Astrophotography processing softwares longer in use, and to be clear, the commercials “[Nebulosity](http://www.stark-labs.com/nebulosity.html)” and “[PixInsight](https://pixinsight.com/)” and freeware and “[Deepskystacker](http://deepskystacker.free.fr/english/index.html)“. What makes it special is the ability to get enlargements of the area photographed, with greater definition, without compromising it with additional noise as would happen oversampleing a 200% crop, and in some cases also allows you to get more signal/detail in that area. Taking a cue from what little I’ve found on the internet about the Drizzle, this is the function that takes advantage of the algorithm called “The Va**riable-Pixel Linear Reconstruction”** which was originally developed at the** Space Telescope Science Institute **to process **Deep Field i**[**mages**](http://en.wikipedia.org/wiki/Hubble_Deep_Field) [from](http://en.wikipedia.org/wiki/Hubble_Deep_Field) the** Hubble Space Telescope.** [https://en.wikipedia.org/wiki/Hubble_Deep_Field](https://en.wikipedia.org/wiki/Hubble_Deep_Field) **Drizzle** is a linear algorithm for reconstruction of downsampled images from ditheri**n**g (*), basically allows you to work in pixel mode doubling the size of each image (triples if you choose the drizzle 3 x). To take effect, the Drizzle, you must have raw data that have these requirements: **Downsampled images:** If the images are already well sampled, the Drizzle won’t give you great benefit. **Images with Dithering**: Drizzle is absolutely necessary and without proper dithering the rebuilding process is not working. **Many images**: Drizzle requires more images than a handful of images that a wide field astrophotography. The more the better, but generally you should acquire at least 20/30 images to get good results. [ *** **] ** **-For dithering applied in astrophotography, also as a function of driving software, means that every single shot has the exact same field resumed (FOV), but always present a small shift, a drift that then generates the final image darker sides those borders. See also: h[ttp://dslr-astrophotography.com/dithering-optimal-results-DSLRs-astrophotography/](http://dslr-astrophotography.com/dithering-optimal-results-dslr-astrophotography/) We could call it vulgarly a crop more powerful, but also a little as if the photo shooting increased three times without carrying those annoying aberrations than a “teleconverter” optic, although of excellent brand you would bring back. A little like giving hormones to the telescope:) or one of his “second life” warning though, this type of processing actually produces the benefits in the image only if it was taken with perfection to the native focal, I mean focusing great Chase very good, otherwise the image produced in drizzle also amplifies these faults! This is the pubblication of Space Telescope Science Institute about Drizzle: And here are some examples to better understand what we’re talking about, before without drizzle to campio full (APS-C) and then Drizzle 2 x: [](https://www.flickr.com/photos/xamad/16908135980/in/album-72157606352390123/) *M51-Whirlpool Galaxy-Celestron optics C11 xlt block mirror mod. f/10 @ f/7 (2200 mm focal length)* [](https://www.flickr.com/photos/xamad/17316090334/in/album-72157606352390123/) *The same stack processed in drizzle 2 x* [](https://www.flickr.com/photos/xamad/28541770740/in/dateposted/) *NGC7293-Helix Nebula-with a 130 Super Apo Triplet f/7 mm (focal 910mm)* [](https://www.flickr.com/photos/xamad/19998339404/in/album-72157606352390123/) *The same stack processed in drizzle 2 x* To learn this technique of elaboration, I suggest you my TUTORIAL “Deepskystacker e Drizzle Function”: [Tutorial: Deepsky Stacker (DSS) and Drizzle function](http://www.xamad.net/blog/en/tutorial-by-astrophotography-deepskystacker-dss-and-the-function-drizzle/) 1e3)g=1e3;else if(~~g Thanks for viewing and bye 🙂 [/sociallocker]