Planetary timelapse - how often do you refocus?

[Stonius (Markus)]

Curious for the guys that do this type of photography.
Do you do a quick refocus every hour?
Firecap is not like Voyager, NINA or SGP in that there is no autofocus routine built in to the framework. It's still manual.


And of course, if you take too long dithering about, you'll mess up the timing of the captured frames and create a 'jump' in the finished animation.


Anyone had to deal with this?


Markus

[Dave882 (David)]

Probably depends on a number of factors, but i'm going to say it should be more frequent than every hour. When the temperature's dropping I've got to refocus my c14 every 15min.

In reality, a timelaps can have 3-5min gaps between exposures and still look pretty smooth so it shouldn't be too hard to refocus in between shots. But it's much much easier if you're focussing on the planet itself and not slewing to a nearby star or doing an autofocus routine. If the seeing is so blurry that you can't get a good clear focus point on the planet itself, I reckon you should wait for better conditions before you spend lots of hours capturing and processing a timelapse.. If you're shooting mono you'll need to refocus between each filter change (but mono's not going to be ideal for a timelapses).

[Stonius (Markus)]

Thanks David, good points! :-)