Friday, 2 September 2016

AstroCrop for Linux

Earlier in the year I reported that Nicola Mackin and I had published an article in Popular Astronomy on AstroCrop, Windows software for the precise cropping of images.

AstroCrop for Windows

This was developed particularly for Bridge camera imaging using a static tripod for the rapid collection of solar or lunar images, that inevitably will have significant movement of the object of interest and that Registax will be unable to cope with the movement between images. The resulting registered, cropped images can then be used easily by Registax for stacking and wavelet processing.
Nicola is a very experienced programmer and has now ported AstroCrop over to Linux.

Splash Screen of AstroCrop for Linux

The cropping area defined

Stack of 98 Bridge camera images cropped in AstroCrop for Linux, Stacked and Wavelet processed in Registax 5.1 in the Windows compatibility layer Wine and Post Processed in The Gimp 2.9, which can work with 16 bit files.


The Linux version will be released as soon as testing is complete and an installer is constructed.

Tuesday, 22 March 2016

Jupiter-Moon Conjunction March 21/22, 2016

A tripod mounted Panasonic Lumix DMC-FZ72 bridge camera was set to ISO 100 and 1/60s exposure and zoomed to F = 35mm, (35mm equivalent of  217mm) to capture the conjunction. A single exposure was captured using a 2s time delay to avoid camera shake. The JPG image was processed in Camera RAW and then Photoshop:



Wednesday, 20 January 2016

88%, waxing, gibbous Moon

A tripod mounted Panasonic Lumix DMC-FZ72 bridge camera at 60x optical zoom was used to image the 88% waxing, gibbous Moon. The camera was set to  ISO-100 and 1/250s exposure at f/5.9. 101 images, were precisely cropped and registered in Nicola Mackin's AstroCrop software, stacked and wavelet processed in Registax 5.1 with post processing in Photoshop.



Sunday, 17 January 2016

How to capture rapidly, register and precisely crop, bridge camera images of the Sun or Moon

On January 15, A tripod mounted Panasonic Lumix DMC-FZ72 bridge camera at 60x optical zoom was used to image the 38% waxing, gibbous Moon. The camera was set to  ISO-100 and 1/250s exposure at f/5.9. 102 images, were precisely cropped and registered in Nicola Mackin's AstroCrop software, stacked and wavelet processed in Registax 5.1 with post processing in Photoshop:

38% waxing, gibbous Moon


The way that large numbers of images are captured in a short time is to use a static, robust tripod, and to hold the camera firmly whilst capturing the images. The camera is set to maximum optical zoom, with an appropriate shutter speed for the subject. the ISO is set to 100 to minimise noise and to set the camera to burst mode. The camera used here captures 3 images per burst, but other cameras may capture more. The Sun or Moon is kept as close to the centre of the field of view of the preview screen and focus lock is used so that the camera does not need to refocus for each burst capture. About 100 images are relatively easy to capture rapidly.
The images captured by the camera used here are 4608 x 3456 pixels in size, which means that even a small apparent movement of the subject between images, is in fact, a very large movement in terms of pixels. Too large, usually for Registax to be able to cope with the movement between images when it comes to stacking the images. What is required is to be able to precisely crop around the Sun or Moon in exactly the same way in every image, so that the cropped images can be presented to Registax with virtually no movement between images. This is a laborious task if done manually, which led Nicola Mackin and myself to develop AstroCrop software for registering and precisely cropping images. Nicola did all of the coding and I produced the required statistical algorithms.
In the Nov/Dec issue of Popular Astronomy, we published an article about AstroCrop:


The software can be downloaded from the website asys-software.co.uk The download website also has a short video showing AstroCrop in action with a small data-set showing extreme movement of the subject between images. There is also a PDF set of instructions on how to use the software.
Nicola Mackin, the programmer of the software was an IT professional for more than 25 years. She ran the European IT technical work for an International printing company. She now runs an independent publishing company aSys Publishing , publishing authors' work to the highest professional standards of the industry.
Nicola is also the programmer of the Aspect Ratio Corrector used to correct images captured by PAL video cameras.

Tuesday, 29 September 2015

Crepuscular rays, Sundogs and Circumzenith arcs

A Panasonic Lumix DMC-FZ72 bridge camera was used in automatic mode to capture these images of atmospheric phenomena:

Crepuscular rays

Best seen when the Sun is low in the sky

Parhelia (Sundogs)

Caused by hexagonal ice crystals

Setting sundog


Circumzenith arc

Caused by hexagonal ice crystals acting as prisms


Thursday, 2 July 2015

Jupiter, Venus conjunction setting over the Afan Valley

A tripod mounted Panasonic Lumix DMC-FZ72 bridge camera was set to ISO 100, at f/5.5, a 35mm equivalent focal length of 183 mm. A 2s exposure was captured of the setting conjunction:




Thursday, 18 June 2015

AR2367 and AR2371 dominating the solar disk

I have been experimenting with how many images can be successfully captured and stacked with an equivalent focal length of 1200 mm with the camera on a static tripod. The more images that can be incorporated into the image stack, the greater the signal to noise ratio and more detail can be extracted.
A static tripod mounted Panasonic Lumix DMC-FZ72 bridge camera at 60x optical zoom, fitted with a Baader solar filter, was used to image the Sun. The camera was set to burst mode, ISO-100 and 1/1000s exposure at f/5.9. Images were captured in bursts of three. 102 images, precisely cropped and registered in Nicola Mackin's AstroCrop software were stacked with optimum derotation and wavelet processed in Registax 5.