Jocular is an open-source, cross-platform desktop software application written by Martin Meredith and designed specifically for EAA. It has extensive features for stacking, stretching, and other image correction. I've wanted to start using it in place of the ASIAIR Pro due to the larger feature set and the failure of the ASIAIR Pro to stack in certain situations. Thanks to a suggestion from Clouzot, I learned there is a way to still use the ASIAIR Pro for focusing, plate solving, goto, and imaging--which it is very good at--by remotely accessing the ASIAIR Pro's filesystem. (You can also use Sharpcap with the ASIAIR Pro this way.) Jocular is mentioned occasionally on this forum but I haven't seen any extensive discussion. I had my first night using it live recently and wanted to share information about the application and the results.
Jocular is written in the Python programming language. If you're at all familiar with Python, you'll find installation a snap. It's slightly more difficult if you're not, but not much as long as you know how to use a command line. Jocular uses a particular framework (Kivy) for its user interface, and when you open Jocular you'll immediately see it looks different than a typical desktop application.
Jocular has an eyepiece metaphor, and the controls are arranged around the perimeter. It's currently showing a stack of 30 mono images from a C8, 0.63x reducer, and ASI178MM. At the top, the number of stacked images is shown. You can change this to show individual subs and remove them from the stack. Next, going counter-clockwise, are controls for how the stack is processed, such as using the mean versus the median of the image values.
Continuing on, we get to the crux: stretching! No histograms here. Instead, Jocular sets the black point. You can adjust the white point by sliding the W, but that typically isn't necessary. You choose one of five stretching algorithms and slide the S to choose the degree of stretch. In the screen shot, I'm using the aptly-named "hyper" stretch with somewhat less than maximum amount of stretch.
Next, there is an "auto" button you can use to turn off the automatic setting of the black point, and use the B slider instead. However, I've found Jocular does a superb job of setting the black point. There are several buttons for displaying information, as well as sliders for the background level, noise reduction, and, most importantly, gradient removal.
"Landscape" lets you take a snapshot of the current view that looks like this:
I think the zoom level is based in part on the object size, but I don't know. You can also toggle this to take a snapshot of the main window. As you can see, the landscape view of NGC 7479 is oriented differently than the "eyepiece" view in the main window above. The eyepiece view is correctly oriented, with North up and East to the left. To get this orientation, you have to run Jocular's plate solving function. Jump over to the upper right, for the "dso," "loc," and settings buttons. After you set the size of the sensor, you identify the target DSO using the "dso" button and then run the plate solver using the "loc" button. This rotates the view correctly.
It also identifies other objects in the FOV that are in catalogues you've loaded into Jocular. In this screen capture, three PGC galaxies are shown and, using a toggle, labelled. The brightest is mag 18.5; it's not visible in this image. Three quasars are also identified by crosshairs, not labelled. Even if you don't use Jocular for stacking, you can use it stand-alone for annotation.
I'll finish up this longish post with a fun feature: you can create an animated GIF that shows the stacking process! Click on the image to see it in action.
Edited by steveincolo, 17 October 2021 - 02:39 PM.