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.** **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: http://cds.cern.ch/record/362045/files/9808087\.pdf   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: \[caption id\="attachment\_157" align\="aligncenter" width\="1000"][](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)\[/caption] \[caption id\="attachment\_151" align\="aligncenter" width\="1000"][](https://www.flickr.com/photos/xamad/17316090334/in/album-72157606352390123/) The same stack processed in drizzle 2 x\[/caption] \[caption id\="attachment\_156" align\="aligncenter" width\="1000"][](https://www.flickr.com/photos/xamad/28541770740/in/dateposted/) NGC7293\-Helix Nebula\-with a 130 Super Apo Triplet f/7 mm (focal 910mm)\[/caption] \[caption id\="attachment\_153" align\="aligncenter" width\="1000"][](https://www.flickr.com/photos/xamad/19998339404/in/album-72157606352390123/) The same stack processed in drizzle 2 x\[/caption] To learn this technique of elaboration, I suggest you my TUTORIAL "Deepskystacker e Drizzle Function": http://www.xamad.net/blog/?p\=497⟨\=en Thanks for viewing and bye :) \[/sociallocker]