Odd histogram
Odd histogram
Okay and one of the posts that shows how to image Jupiter I see that his histogram starts on the left hand side and goes to the right. Mine oddly is directly in the middle of the histogram and looks more like a ghost when he is saying that he turns off his exposure until it looks similar to a whale's head. Mine looks more like a ghost why is mine not starting from the left and jetting to the right? And I see many other people's post that there starts from the left and works its way into the middle. Do I have a setting off that mine never touches the left hand side of the histogram?
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Re: Odd histogram
Hi,
it's a bit difficult to tell from the description quite what is going on. Is there any way you could send a screenshot - if you include both the histogram area, the image itself and the control area so we can see control values, that should help.
thanks,
Robin
it's a bit difficult to tell from the description quite what is going on. Is there any way you could send a screenshot - if you include both the histogram area, the image itself and the control area so we can see control values, that should help.
thanks,
Robin
Re: Odd histogram
Mine looks like the pic on the left. And I see other people's look like the picture on the right. I'm not by my computer right now so I can't give you an image.
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- Screenshot_20211006-115054~2.png (288.11 KiB) Viewed 754 times
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- Screenshot_20211006-115150~2.png (18.61 KiB) Viewed 754 times
Re: Odd histogram
Okay my phone switched them around mine looks like the bottom picture
Re: Odd histogram
I wrote the manual pages that you are looking at.
The histogram shape shown would be obtained if the object was a disk surrounded by black. There are 2 peaks - the left hand one for the black pixels of the background and the right hand one for the bright pixels of the object. This is commonly referred to as the 'classic whale shape'. Once that histogram shape is achieved the camera settings are such that reasonable data will be obtained. For Jupiter, I set gain to around 70% of the camera's maximum value and adjust exposure until the right hand side of the histogram is around 80%. This gives a systematic way to achieve decent images. The figures are not 'cast in stone' but are 'guidelines'.
The other case is when the object fills the screen and there is no black surround - better understood with a lunar image. In this scenario, as there is no black background, the histogram will not touch the left hand side - in this example the histogram starts around 20.
Hope this clarifies.
Dave
The histogram shape shown would be obtained if the object was a disk surrounded by black. There are 2 peaks - the left hand one for the black pixels of the background and the right hand one for the bright pixels of the object. This is commonly referred to as the 'classic whale shape'. Once that histogram shape is achieved the camera settings are such that reasonable data will be obtained. For Jupiter, I set gain to around 70% of the camera's maximum value and adjust exposure until the right hand side of the histogram is around 80%. This gives a systematic way to achieve decent images. The figures are not 'cast in stone' but are 'guidelines'.
- disc-surrounded-by-black-background.JPG (27.94 KiB) Viewed 713 times
The other case is when the object fills the screen and there is no black surround - better understood with a lunar image. In this scenario, as there is no black background, the histogram will not touch the left hand side - in this example the histogram starts around 20.
- no-black.JPG (55.72 KiB) Viewed 713 times
Hope this clarifies.
Dave