Re: Tracking and guiding with and without encoders - Part2
Michael Fulbright <mike.fulbright@...>
I haven't given it much thought but if you assume a Gaussian profile for your stars and the guide errors are normally distributed I would think the final FWHM of the star broadened by guide errors would add in quadrature.toggle quoted messageShow quoted text
sigma_F = sqrt( (sigma_*)^2 + (sigma_g)^2)
where sigma_F is the final sigma of the Gaussian star profile, sigma_* is the unbroadened star profile, and sigma_g is the error guiding.
If you have seeing like me and most stars are around sigma_*=2 arcsec and sigma_g=0.4 arcsec I get sigma_F = 2.04 arc sec.
I'm sure there is work on this in professional journals if someone really wanted to know the answer.
Just a quick search I found this:
Seems to consider many sources that must be controlled to give the best image resolution including atmospheric and guiding effects.
You could do a test and take a < 5 second exposure of a bright star cluster then take a 300s exposure of a fainter star field and compare FWHM. Presumably the short exposure is roughly measuring your optics and short term turbulence while the longer would incorporate guiding errors as well.
On 9/17/19 5:14 PM, badgerz49@... [ap-gto] wrote: