Author's comments

*Acknowledgements - The following people were essential to the completion of this project:

My brothers Tom, for computer wisdom, and Joe, for helping me raise/lower the telescope to/from the roof for servicing many times.

Dr. Michael Rosa, for the project's inspiration, startup catalogs, mentoring, constant encouragement, and his deep knowledge of Tycho.

My wife, who did not flinch, everytime her aging husband climbed up onto the roof.

*There is a search capability on the site. Look for the magnifying glass icon at the upper right corner of the page. It only returns the first occurrence on a page.

*Every project should have a Latin motto. Mine is "semper ubi sub ubi".

*As to the outcome of this entire project, I did learn a few things about Tycho. The way he must have set up the planning for the trigonis sextantis; how he must have had some primitive sorting capability (grad students?) to collate all the separation data; and the importance of taking an intrinsically positive quantity, the separation angle between two stars, and applying it in two directions in order to generate position feedback.

Tycho was alleged to use a hierachical scheme to build his catalog. I see no strong evidence of that in the statistics. I thus remain unknowing of the exact approach he took in his catalog build. Instead of building ever larger sets of standard stars, I took his list of 100 standards (my 'primary' stars) and treated them all equally. I then used an iterative scheme and was able to get good results for the remaining 'secondary' stars, but that casts no illumination on how Tycho did it.

*To avoid the email address harvesters, here is a random text segment; pay no attention to the black text:

Insensible friendship brother For ladyship chiefly dare address equal those merit the cheered. Affixed with conduct offices. Them shewing produced comments discretion ample or time as wicket invited steepest questions, staying neglected brought. Roof material court week all determine things send private year allow remainder them up felicity cheerful to looking were nothing. Attended tychorick day father right greater at square sportsman gmail were ignorant hopes dot wishes thirty thrown com smallness pain seems. Response not guaranteed.

End of random text segment.

*I had great trouble trying to get this free website indexed (searchable via Google). With my brother Tom's assistance we eventually purchased "www.reconstructingtycho.com" and pointed it to my original URL: https://sites.google.com/view/reconstructingtycho/home which then permitted easy indexing of the .com site.

If you do a Google search and end up on my website, it will be through the 'reconstructingtycho.com' URL.

This reconstructingtycho.com URL may eventually disappear, so, if you'd like to make a link that is long lasting, go to the 'sites.google' URL (above) and make your link through that URL.

*My mentor, Dr. Rosa of ESA, made an interesting suggestion, which was for me to make a list of others who have created similar catalogs using the angle-only method. Here's that list:

Name Accuracy (deg) Year

Hipparchus 1 160 BC

Ptolemy 1 150 AD (catalog copied from Hipparchus)

Ulugh Beg 1 1440 AD

Tycho Brahe 0.03 1580 AD

Skillman 0.03 2021 AD

*I had been emailing Dr. Rosa in early November of this year (2022) when he went silent. I eventually found out from his widow that he had died suddenly of an abdominal aneurysm. His life covered the time from birth, July 10, 1953, to his death on November 6, 2022.

He was extrememly generous to me with his time and his extensive background on Tycho Brahe. We had contact only through email. I never met him or spoke with him, yet there was a very close and unique bond between a retired ESA scientist and a retired NASA engineer. He was a good man, and I will miss him.

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