Tuesday, February 24, 2015

NFeeder Progress; A Good Imaging Night at Last?

I added more to the Nebulosity script generator/feeder program NFeeder:
  • It now recognizes the time lapse setting, although I really don't understand the implementation of this in Nebulosity. (If you specify an exposure time of 15 seconds and a time lapse of 120 seconds, consecutive exposures start at 150s intervals. Time lapse is usually taken to be the time between consecutive frame starts. An alternative would be to treat it like a delay, setting the time between when a frame ends and the next starts. In the example this would give 135s between consecutive frame starts. I can't think of a rationale for 150s between frame starts given a time lapse setting of 120s.)
  • The status indicator now tries to show you when you're within a time lapse delay, although the above problem messes it up.
  • It can now parse a loaded script and set all the GUI widgets accordingly.
  • It now provides the total amount of exposure time the script will require and includes it in the script as a comment. At present it doesn't distinguish between light, dark, and bias frames; they all count as exposure time. I may change this. Nor does it take into account the time lapse setting. I assume total time when time lapse imaging is not as important as the clock time span of the session.
  • Auto-cooldown is now implemented. You specify the ambient temperature (to within the nearest 5 degree multiple), the set point, and the size of the temperature and time steps. You can also specify a final time interval to allow the camera to come to thermal equilibrium once it's been set to the set point temperature. The values of time delays must be found empirically. The following issue with the Delay command may impact how well this works--if it works at all.
  • I eliminated the possibility of delays after filter changes because of strange behavior by Nebulosity. Invoking the Delay command from clipboard commands seems to cause Nebulosity to ignore the clipboard for quite a bit longer than the delay itself. It's possible I may have to apply a workaround in which NFeeder itself provides the delays.
It's now in its fourth incarnation so it has a version number of 0.4! If you choose to download and try it, be aware that the help information is not up to date and won't be until the development of the beta is almost done.


Imaging tonight? Beautiful clear sky and a temperature around 30F now, but it will be falling through the upper teens and remain quite breezy when it gets dark.  Almost a first quarter moon, too. But fine for a 135mm Ha image of Sh 2-264, the big patch of nebulosity around Orion's head. It will be nice to get another winter object done.

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