Hi all,
We have just released new versions of the standard StarGenerator and StarAlignment tools as an update for all supported platforms. These tools can now work with comma-separated value (CSV) text files.
In its new
Generate CSV Text File working mode, StarGenerator writes a CSV file encoded in 8-bit ASCII format, instead of rendering a synthetic star field as a new image. The generated CSV file has a first row with the projection dimensions (width,height). Subsequent text lines provide data for the set of stars within the projection coordinates (xPos,yPos,flux). These are the first 16 lines of an example CSV file:
4096,4096
4043.59,3980.36,1.5129e-04
4043.54,3980.13,1.2017e-04
3954.77,4027.85,6.3649e-05
3896.12,4052.81,1.0962e-02
3886.20,4074.14,3.0187e-04
3861.86,4065.13,1.4448e-04
3829.01,3976.81,1.0960e-04
3819.04,4039.27,1.2241e-04
3763.50,4044.26,5.6473e-04
3721.76,3998.48,2.4650e-04
3703.09,4067.60,6.3066e-05
3653.61,4004.56,8.3138e-05
3637.62,3969.14,7.5822e-05
3586.79,4032.09,6.9151e-05
3561.83,4044.34,1.1798e-04
In these files, coordinates are expressed in pixels and the third column of each star line represents the star's
flux scaled linearly. For each star, the flux value is computed as:
2.512Mmin - Mstar
where M
min is the catalog's minimum stellar magnitude (corresponding to -1.5, or the approximate visual magnitude of Sirius) and M
star is the catalog star magnitude.
The new version of the StarAlignment tool can use these CSV files as alignment references. When a CSV file is selected as reference, the corresponding star data are acquired in a very fast and accurate way, without requiring any access to the original image.
The main advantages of CSV star lists are:
* Execution of StarGenerator instances is extremely fast in CSV file generation mode.
* StarAlignment acquires reference star positions much more accurately than by exploring a synthetic star field image.
* StarAlignment's execution is faster because the initial structure detection phase is not performed for the reference image.
With these improvements, we have released an official version of
Andres Pozo's ImageSolver script with the following enhancements:
* Works with CSV star lists, which removes the bottleneck of image generation with the StarGenerator tool.
* StarAlignment is more accurate because it now reads positional and brightness data directly from the original catalog, without the degradation involved in representing the data as an image. In addition, StarAlignment execution is also faster.
* Since the script is now much faster, more iterations can be performed (4 or 5), which leads to more accurate plate solvings.
Thanks to Andres Pozo for writing and releasing his ImageSolver script. This script is a nice example of an extremely useful and well designed tool implemented with PixInsight's JavaScript runtime.
