Free Astronomy Magazine – January-February 2019 Issue Available For Reading And Download

Above: This illustration shows what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credit: SETI Institute.

Slightly late to the posting game – the January-February issue of Free Astronomy Magazine is available for your reading and downloading pleasure. Highlights from the original content (h/t Michele Ferrara) include an excellent introduction to panspermia and the wonderful ways in which small, dense solar systems (like TRAPPIST-1, one of the only solar systems with its own website – www.trappist.one) might serve as test beds for better understanding if such an explanation is applicable to ourselves and our Earth – either from a local source (Mars?) or from the greater beyond.

Please download, read, and pass along. Also, check out the many back issues at www.astropublishing.com

astropublishing.com/1FAM2019/ | Direct PDF

Click the Table of Contents image below for a full-size view.

The 16-inch f/4.5 Collapsible-Truss Dobsonian From New Moon Telescopes – Feature Article (Again) In Astronomy Technology Today

And happy new year.

With Operation: How-The-Hell-Do-I-Do-It-In-Gutenberg well underway, a quick post to mention the re-publication of a New Moon Telescopes review in Astronomy Technology Today (Vol 12. Issue 5) that first appeared in ATT’s May-June 2013 issue (a post about that publication resides on this site HERE).

So nice they printed it twice.

While the “classic” NMT scope has gone into discontinuation on the website in favor of the “hybrid” designs (the reprinting of the review of the “classic” model is perhaps not the best of timing), let there be no doubt that the long-short of the article and its reprint stands.

In the last seven year, I’ve bought extra pairs of binoculars. I’ve picked up sky charts. I thought about adding to my Televue collection (then won a Delos at Cherry Springs Star Party 2014 a few years back, scratching that itch). I even went so far as to pick up an iOptron SkyTracker to merely dabble in astrophotography.

In all that time, “Ruby” (NMT #1) has performed so well that I’ve never felt the need to even consider buying another telescope. In a hobby that caters to gear-hounds like no other, that’s about as strong an endorsement as I can make. Simply, Ryan Goodson continues to make the finest Dobsonian scopes on the market today. Period.

And make sure you subscribe/renew your subscription to support Astronomy Technology Today (as I did before the reprint!), which remains one of the best sources for in-depth equipment reviews and excellent commentary from real, honest-to-goodness amateur astronomy contributors.

Evaluating The Friction Of Rotary Joints In Molecular Machines

Howard Lovy’s name came across my calendar (happy birthday!) and Josh Hall published a fresh post to “Where is my Flying Car?” – seems like a perfect time to post an everything-new-is-still-new-for-the-first-time-type update.

Published way back in 2017 in Molecular Systems Design & Engineering; reportedly one of the most-read Q3 2017 articles to boot. Also my first foray into arxiv territory for those limited in their journal access (arxiv.org/abs/1701.08202).

Tad Hogg*a Matthew S. Moses*b and Damian G. Allis*c

a. Institute for Molecular Manufacturing, Palo Alto, USA
b. Independent Consultant, Lafayette, USA
c. Department of Chemistry, Syracuse University, Syracuse, USA

Abstract: A computationally-efficient method for evaluating friction in molecular rotary bearings is presented. This method estimates drag from fluctuations in molecular dynamics simulations via the fluctuation–dissipation theorem. This is effective even for simulation times short compared to a bearing’s energy damping time and for rotation speeds comparable to or below typical thermal values. We apply this method to two molecular rotary bearings of similar size at 300 K: previously studied nested (9,9)/(14,14) double-walled carbon nanotubes and a hypothetical rotary joint consisting of single acetylenic bonds in a rigid diamondoid housing. The acetylenic joint has a rotational frictional drag coefficient of 2 × 10^-35 kg m2 s^-1. The friction for the nested nanotubes is 120 times larger, comparable to values reported by previous studies. This fluctuation-based method could evaluate dissipation in a variety of molecular systems with similarly rigid and symmetric bearings.

Mol. Syst. Des. Eng., 2017, 2, 235-252 (10.1039/C7ME00021A, direct link)