Confusing HFR results


#1

I’ve had no luck getting AF to work with my AT6RC so I decided to spend an evening playing around with manual focusing using HFR results from single images taken through the Frame and Focus module. I took images of the stars around Regulus, but without the bright star in the FOV. A series of single images were taken with a DSLR at ISO 6400 at 8 sec. When each image loads a HFR value pops up on the image and the HFR value in the Image analysis module also changes, thohg these values appear to be not correlated with each other, and a bunch of stars in the image are annotated with circles and HFR values. That makes sense. The problem is if I then click on the “star” icon on the toolbar to turn of and then on again HFR calculation, I get a very different HFR result displayed on the image. If I turn it off then on again I get the same value, so what is the first value that automatically came up when the image downloaded, and why is it different than after I “reset” the calculation?


#2

Automatic HFR is capped at sample sizes of 100. HFR run manually with the star icon will use as much data as it can find. This is done in order expedite manual focusing on slower machines. You are seeing a difference in mean values most likely.


#3

i have it working OK with my AT6RC+moonlite, except for the fact that i had smart focus turned on for a while which would sometimes cause the AF routine to get lost. recently i switched that off and i have not had any focus failures as far as i can tell… anyway you should be able to get tis working; maybe you need longer exposures? i am using 20s exposures thru an L filter on a mono CCD.


#4

Ken, Thanks. That would explain it.

pfile, Thanks for the tip. I will check the Smart Focus setting.


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