Dark library generation

[Phoenix]

This is a feature that was asked for years ago, and we still dont have it. For the love of all that is holy can we please get a dark library generator, where we can put in a range of exposures and gains, and have it iterate on cloudy days to grind out darks so we dotn have to waste good observing time time?

I love most of whats in Sharpcap and its become my main capture program, but this one thing, drives me absolutely insane as to why its not already a thing.

[turfpit]

Phoenix

Sequencer perhaps???

Dave

[admin]

Hi,

The sequencer is probably the right solution for this (even if it requires some improvements to the sequencer to make it easier). That's certainly my preference for things like this where I get the feeling that a feature isn't going to be widely used. Of course if I get lots of other people chiming in to say that they also want a tool to create a dark library then I may need to re-assess that...

Actually, the sequencer can currently be used for that, subject to some limitations. There is a step to create and use a master dark frame, with the option to set how many individual darks to capture, so that is usable. There are steps to repeat blocks of sequencer code, which is again fine. What isn't quite available in the sequencer is a clean/easy way to work through a range of exposure or gain values

One approach would be to use loops like the below - this would capture darks at 30s, 45s, 60s, 75s and 90s and at gains 0,50,100,150,200 for each exposure. At least, it would do that subject to tweaking the 'Adjust' value for exposure - depending on the type of camera being used, the raw value for exposure may be in seconds, milliseconds or microseconds, so the adjust amount would need to be 15, 15000 or 15000000. This gets you a series of darks, but as you see not easy to pick exactly the gains/exposures.

Code: Select all

SEQUENCE
    SET EXPOSURE TO 30
    LOOP 5 TIMES
        SET GAIN TO 0
        LOOP 5 TIMES
            CREATE MASTER DARK FROM 10 FRAMES
            ADJUST CONTROL Gain BY 50
        END LOOP
        ADJUST CONTROL Exposure BY 15
    END LOOP
END SEQUENCE

Another approach would be to use subroutines, like this

Code: Select all

SEQUENCE
    DEF SUB "Capture Dark"
        CREATE MASTER DARK FROM 10 FRAMES
    END SUB
    DEF SUB "Capture Dark For Gains"
        SET GAIN TO 0
        GOSUB "Capture Dark"
        SET GAIN TO 60
        GOSUB "Capture Dark"
        SET GAIN TO 120
        GOSUB "Capture Dark"
        SET GAIN TO 180
        GOSUB "Capture Dark"
    END SUB
    DEF SUB "Capture Dark Library"
        SET EXPOSURE TO 15
        GOSUB "Capture Dark For Gains"
        SET EXPOSURE TO 30
        GOSUB "Capture Dark For Gains"
        SET EXPOSURE TO 60
        GOSUB "Capture Dark For Gains"
        SET EXPOSURE TO 120
        GOSUB "Capture Dark For Gains"
    END SUB
    COOL DOWN TO -10 RATE 8 TOLERANCE 1
    GOSUB "Capture Dark Library"
END SEQUENCE

At the expense of longer code, you get to pick the exact gains/exposures to capture your dark frames at. In this case there is no need to worry about the weirdness of camera exposures being measured in different units - the 'Set exposure to' step understands that and will deal with it while the more generic 'adjust <control> by <amount>' does not understand that, so the sequence creator needs to handle the problem.

cheers,

Robin