Deep sky seq planner- smart histo

[stbkaiser]

Hi Robin
Using your DEEP SKY SEQUENCE PLANNER
In that under CAMERA SETTINGS
you have the option to MEASURE THE SKY BACKGROUND
" and computing the most appropriate values based on upon the SharpCap Smart Histogram functionality."
When I use this function will it let me set the parameters for the SMART Histogram operation, such as
MEASUREMENT measure brightness of BLUE channel
IGNOR image edges /corners

Or do I need to run SMART Histogram by itself, set the parameters, and then Deep Sky Sequence planner will use the previous values when it runs SMART Histogram?

Thanks
Steve

[admin]

Hi Steve,

it will default to the Green channel for a colour camera and obviously luminosity for mono. The avoid edges option will be turned on. You can't alter these via the sequence planner, but you can if you use the 'Advanced Edit' button to transfer the plan into an editable sequence.

Oddly I just discovered that testing that step seems to fail if the camera hasn't already taken at least one frame in still mode - I will try to work out why and fix it.

cheers,

Robin

[stbkaiser]

Great.
If I'm using a Filter (required for in town imaging) L-enhance , dual band , with my ASI2400 MC pro color camera,
Should I be using the Green channel (brightest) or the Blue (darkest) for the Smart Histogram to gauge the sky brightness.

Thanks.
Steve

[stbkaiser]

HI Robin
Interesting tonight.
I am running the same setup/ equipment as the past 2 nights.
Tonight I ran the Smart Histogram function using the brain tool by itself. (not from within the Start Capture/ Deep Sky sequencer)
The sky is the same as past nights.
The Smart Histogram came up with the same Gain but the recommended exposure time was 90 sec.
The smart histogram settings set from within Deep sky imaging was repeatedly 25sec.
I don't understand why there would be that much of a difference in calculated exposure time.
Any Ideas?
Thanks
Steve

[admin]

Hi Steve,

your filter lets through very little in the blue part of the spectrum, so blue will be very dark and also not contributing much to the final image, so it's probably best to ignore the blue channel and focus on the green.

I suspect that the cause of the different exposure recommendations was down to different values measured for the background. You should be able to find the measured values from the sequencer measurements in the log. It would be worth checking first from the log that the options relating to measuring the background (ignore edges, channel) are the same in both cases. Also check the value for 'maximum noise increase %' which is in the UI and can be adjusted. For the sequencer, that defaults to 10.

cheers,

Robin

[stbkaiser]

Hi Robin
Maybe i am misunderstanding something about executing the Smart Histogram .
Should I get the same exp time, gain and other settings if I run it from the Deep Sky sequencer or if I run it from the Tool drop down menu using the brain function?

I just ran a test this evening.
For the same sky location, and camera cooling setting.
I ran the Smart Histogram using the Tool dropdown.
I then used the Deep sky sequencer to run the Smart Histogram
I then ran Smart Histogram using the Tool dropdown again.

The Exp time for Smart Histogram using the Tool dropdown was within a few seconds of each other (99.8 and 104)
The Deep sky sequencer run of the Smart Histogram returned a value of 27.6sec.

I checked the Histogram settings (green channel & ignor edges) with the EDIT function in the sequencer and they were the same as the Drop down Smart histogram settings.

Am I doing something wrong in the Deep sky sequencer?
Thanks
Steve

[admin]

Hi Steve,

if all the settings used for the measurements by the smart histogram window and the sequencer are the same then you should get the same value - that's what I would expect anyway.

I will test myself when I'm looking into the bug of the first frame not capturing and see if I get the same results in both places. If I do get the same results then that would suggest to me that somehow the measurement settings are different - maybe I can make SharpCap dump the settings to the log
as well as the results, which would help diagnose this.

cheers,

Robin

[stbkaiser]

Robin
Thanks for looking into this for me.
My main concern would be if I use the Smart histogram within a sequence for multiple targets in one night.
If it shorts me on the exposure time, as compared to the Tool dropdown operation, then I can't take advantage of your calculations for optimal capture settings during a sequence run.
It is interesting to note that the exp time generated by the Sequence call to Smart Histogram has been consistent within a few sec (23-26) over the past couple nights.

For now I use the Tool, dropdown Smart Histogram settings ,(which seem to be more realistic) and don't run Smart Histogram within the sequence.
Not a big rush on this.
take care
Steve

[admin]

Hi Steve,

I did test this and as far as I could tell if the settings were the same then I got the same results. However, if you have selected 5% noise limit in the smart histogram window, the sequence planner will run with the default (10%) and suggest a lower exposure. To be sure of what is going on I have added an extra line of logging to the sequence planner version that will record all the settings being used.

I also found and fixed the issue with the first frame going wrong - Altair camera specific after switching the camera from live mode to still mode.

cheers,

Robin