Spreadsheet to provide imaging calculations in one place

[iapa]

I have been working on an EXCEL spread sheet (work in progress) to allow me to select my kit and calculate FoV, effective focal length, f ratio, optimum exposure, effective imaging circle and guiding pixel scale.

This is attached for critical comment.

Astrodata Shared.xlsx

If 50+ individuals approve this I will do a usage video.

The tabs with data in the names are tables where you can add new products by entering details at the blank row at the bottom.

I will be adding calculations to provide total load vs mount payload shortly.

 

Edited May 30, 2022 by iapa

[iapa]

I have updated Astrodata Shared.xlsxto look neater.

It will also now update the calculations for unity gain and exposure based on selected imaging camera; IF you have Sharpcap Sensor data for your camera.

Added graphs of e/ADU, read noise and dynamic range for selected camera.

Notes

1. when adding SharpCap data, the camera name must match the camera name in 'camera data' tab.
2. included data was gleaned from the internet or measure on my cameras, and will not necessarily match yours, particularly sensor data.

Hope this proves useful to some.

Edited June 3, 2022 by iapa
typos corrected

[Xilman]

On 03/06/2022 at 16:25, iapa said:

I have updated Astrodata Shared.xlsxto look neater.

It will also now update the calculations for unity gain and exposure based on selected imaging camera; IF you have Sharpcap Sensor data for your camera.

Added graphs of e/ADU, read noise and dynamic range for selected camera.

 

This looks rather useful. Would you like to receive updates?

I can provide information about Starlight Xpress cameras, for instance, and could also report back a few tyops I discovered in the current version.

Paul

 

[ollypenrice]

What do you consider to be the importance of F ratio? What about pixel size?

Olly

[iapa]

On 10/06/2022 at 19:17, ollypenrice said:

What do you consider to be the importance of F ratio? What about pixel size?

Olly

F-ratio is used to estimate sky background noise, and thence an approximation for exposure length.

The sheet uses pixel size (and f-ratio) for field of view using the formula 180 x π (2*ATAN((0.5*Sensor__h__mm)/(Binning*combined_focal_length)))

Pixel scale is pixel size *206/effective fl.

I'm not setting any importance to any factor, merely, putting the calculations in one place.

In my research I also found, yesterday, that something similar has already been produced on  Astrofriend's website. So, I may discontinue this project rather have duplicated sources.

Edited June 12, 2022 by iapa

[ollypenrice]

Thanks. I'm not a great theorist but it seems to me that the information we really need, and don't have unless we work it out ourselves, is the value for area of aperture relative to area of pixel. F ratio was OK in the days of film but when we introduce pixels it's the flux per pixel which matters.

Olly

[iapa]

easy enough to add I expect,

1. aperture is optic diameter^2*π/4 mm squared
2. pixel area pixel width/1000 * pixel height/1000 mm squared

do you want aperture area : pixel area or vice versa?

One will be very large in the order of 1x10^9, the other very small, 1x10^-10

Adding calculation for pixel flux should be straight forward - let me dig up the calculations from somewhere.

Edited June 12, 2022 by iapa

[iapa]

On 10/06/2022 at 14:02, Xilman said:

This looks rather useful. Would you like to receive updates?

I can provide information about Starlight Xpress cameras, for instance, and could also report back a few tyops I discovered in the current version.

Paul

 

Of course, feedback is welcome.

Camera data is useful, and will be appreciated, I just need to make it more obvious the data provided is sample and will vary per individual camera.

I will be adding my ASI 1600MM, another 183MC, 120MM and 174MM once I have time.

[iapa]

• minor changes to layout (again 🤪)
• added aperture area : pixel area ratio as a prelude trying yo get flux per pixel
• now displays an asterisk for items in various data tabs to when "owned" field contains "y"
• added colour to data tabs
• reviewed calculations against AstroTools utilities to validate results

 

Astrodata Shared.xlsx