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Astrofriend
26-10-2017, 07:45 AM
Over the years I have done a lot of Excel calculation to solve my astronomy problem when I try to make parts work together. Most of them has been my private and only in Swedish, some of them I have published on a Swedish forum and I believe some people have found them useful.

Now I decided to translate them into English and put them on my homepage for downloading.

It's always hard to understand Excel sheets that others have put together, but I hope that these ones with a little help of the instructions on my homepage could be interesting and useful to some of you.

http://astrofriend.eu/astronomy/astronomy-calculations/astronomy-calculations.html

Beware that it could be something wrong in the calculations, if I find something I try to correct it.

I don't take any responsible of it, you use them at your own risk !

/Lars

bojan
26-10-2017, 08:24 AM
Awesome, thank you!
I am sure there will be something useful for me there.

Crux
26-10-2017, 10:03 PM
Lars,

Thank you for the work you have done on this and making it available to the community.

Astrofriend
20-12-2017, 12:04 AM
Hi,
Happy to hear that maybe you can find it useful.

Now I'm in the learning process how to do the calculation direct on the web page.

I have started with the first one, which is not in the excel sheet.
In this calculation you find how many pixels a star moves when you have the camera on a tripod (without a motor). It not just calculate for the eclipta, it do it for the DEC angle where the center of sensor is pointing, and the bottom an top of the sensor along the DEC axis. The last two could be important when having wide angle lenses.

Take a look:
http://astrofriend.eu/astronomy/astronomy-calculations/max-exposure/max-exposure.html

This is very new for me, what I have understand you must have a HMTL5 compatible web browser.

I will develop it further.

Merry Christmas and a Happy New Year to all of you!

ps.
A curious question from a man living in the northern hemisphere. How do you orient your camera, the top of image to the south pole, which would be most natural, or to the north as the maps are usually orientated in the books?

/Lars

bojan
20-12-2017, 05:35 AM
I think North up is a standard.
Same as geographical maps.

Astrofriend
09-01-2018, 10:06 AM
Hi,
Get correct focus is always tricky, sometimes the automatic focus function works, sometimes not. Not uncommon that I spend one hour to find the optimal focus point. Now I have done this excel sheet that could assist me. It's still in development process.

I have added a new excel sheet, this one will calculate where the best focus is from a table of your focus positions and FWHM numbers. It fit a second degree polynomial to your numbers and find the focus point even if it's between your numbers.

If you have temperature compensation activated it's better to deactivate it during this process.

http://www.astrofriend.eu/astronomy/astronomy-calculations/excel-sheets/astronomy-calculations-excel.html

/Lars

Astrofriend
29-01-2018, 10:15 AM
The last days has been productive, I have now transformed one more page of my Excel sheets, the Light Pollution calculator to a new Web Calculator page.

I added a lot of new links with information, and also now tested that the calculation was correct, It at least look that now.

You can read more here if you find it interesting:
http://www.astrofriend.eu/astronomy/astronomy-calculations/skybackground-magnitude/sky-background-magnitude.html

I now know that if I move from my balcony to a really dark place the sky background will be 5 magnitudes weaker or 1/100 of the flux. At the summer house I gain 3.6 magnitudes a typical night.

/Lars