Getting Started

These are the important points to consider in SharpCap when attempting to capture a reasonable video of Jupiter:

·         Set the Gain to 60 – 70%.  (70% if using a Barlow).

·         Start the Histogram ensure the Logarithmic checkbox is selected.

·         Adjust the Exposure until the right-hand side of the histogram is at 80%.

The following need to be considered when trying to balance gain, exposure and frames per second (fps).

·         Using a filter may require more gain (or longer exposures) to increase brightness levels.

·         Using a Barlow will require more gain (or longer exposures) to increase brightness levels.

·         Higher gain adds noise but this can be averaged out in stacking.

·         Blurring caused by atmospheric seeing fluctuations cannot be cured hence a high frame rate is desirable to improve image quality.

·         Exposures of less than 30ms have a chance to ‘freeze’ the seeing thus try to capture at 30 fps or better.

The calculation is:

fps = (1 second)/(exposure)  

fps = (1000)/(exposure)                [with units in milliseconds (ms)]

As an example, an exposure of 250ms would give:

                1000/250 = 4 fps

As an example, an exposure of 30ms would give:

                1000/30 = 33fps

All this will vary depending on factors such as atmospheric conditions, proximity of the moon and equipment.  As a general guideline:

lower exposure => higher frame rate => better image 


 

For this scenario, a large planetary disk, the shape of the histogram (with a logarithmic vertical scale) should be a ‘whale’.  See http://docs.sharpcap.co.uk/2.9/#The%20Histogram for further information and background reading.  In the picture below, SharpCap is shown ready to capture with the histogram undocked.

image