# Basic celestial data

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complete beginner here, only got into star gazing a few days ago using my friend's telescope and I don't really understand at all what any of the measurements mean.

Anyway, talk about jumping in the deep end, but I'm poking around Nasa's Intergalactic Database, but sadly it's all greek to me: http://ned.ipac.caltech.edu/

Here's a galaxy: NGC 7590

Here's its basic data:

EquJ2000.0 RA

EquJ2000.0 DEC

Velocity km/s

Redshift / z

Magnitude / Qual Filter

Separ arc min

Now I'm afraid I don't really understand what any of these measurements and their values actually mean.

I remember from school what Red Shift is, its the wavelength increasing becoming 'stretched' making the light seem to appear more reddish the faster an object is accelerating away from us. But what is that z unit?

I'm afraid I really don't have a clue regarding anything else… spear arc min, magnitude / qual filter?

Is there a book for a brief understanding of these units? Not out to solve problems regarding celestial mechanics, I just want the NED to make a bit more sense to me so I can visualize these objects.

DEC :Declination

RA :Right ascension

Redshift / z :use to calculate velocity over earth z axis (azimuth)

Magnitude/ Qual Filter : zoom into image filter quality (??)

Separ arc min : if is a group as cloud magallans

If you browse further down the page, there are details for each of the top table data.

So RA and Dec give you coordinates (Right Ascension and Declination, like longitude and latitude). There is a designation J2000.0 which tells you the zero point to which the coordinates relate (remember, the Earth wobbles, so any coordinate system tied to Earth changes over time, hence a zero point), in this case the year 2000. The Equ. in front of that means equatorial, which ties is directly to the earth axis (poles & equator; the latter explains the name).

Redshift (z is the symbol for redshift) for a distance estimate.

Qual probably stands for qualification, for example the type of galaxy. It's likely not related to the filter. The type of galaxy would be the classification, which is further down the page.

Magnitude is the brightness, and Filter the filter it is measured in (most astronomy is done in a filter, to obtain a brightness in a specific wavelength range. Eg, red, blue, green, uv, infrared, H-alpha, Oxygen filters).

Separ arc min: the separation (or more likely, the diameter) in minutes of arc (so in 1/60 of a degree). You can't really measure the actual size (unless you trust the distance estimate), but you can measure the size as a angle projected on the sky. That's what it says here (e.g., the sun and the full moon are about 0.5 degree, or 30 arcminutes, "wide").

As mentioned at the start, browse down to get more in depth information, which may shed a bit more light on what the top table abbreviations actually mean and indicate.

RA and DEC are the coordinates on sky.

• RA (Right Ascension) is the angular position measured eastward in a full circle along the celestial equator.
• Dec (Declination) is the angular position measured from the celestial equator in either the north (positive) or south (negative) direction. $+90,^{circ}$ is the north celestial pole, $-90,^{circ}$ is the south.

Velocity (km/s) is the radial velocity that the galaxy has away from or towards the earth.

Redshift (z) is basically a distance estimate based on observing the amount that the light of the object is redshifted due to it's movement away from us. (Since galaxies farther away will appear to move away faster according to Hubble's Law) If you understand the Doppler effect, the equation for its definition is pretty simple: (from Wikipedia's "Redshift" page)

The higher z is, the further away in distance (and time) the galaxy is.

Magnitude / Filter : Magnitude is the measure of brightness of the object. This depends on which filter (at which wavelength range) the observation is made in. For this measurement: smaller values = brighter. The sun is something like -27, the brightest star Sirius, is around -1.5, the faintest stars visible to the naked eye are around +6 to +8.
The galaxy page you linked only lists the magnitude - I don't know why the filter doesn't seem to be there.

Separ. arcmin : The separation in arc minutes. (Probably meaning size, or diameter of the galaxy) An arc minute is an angular unit of size on the sphere of the sky (the same units as declination). So one arc minute is 1/60th of a degree, and there are 360 degrees spanning the entire celestial sphere.

Sorry, I don't know the "Qual" measurement.

## What is Astronomy?

Astronomy is the scientific study of celestial objects (such as stars, planets, comets, nebulae, star clusters and galaxies) and phenomena that originate outside the Earth’s atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe.

Astronomy is one of the oldest sciences. Early cultures such as the Babylonians performed methodical observations of the night sky, and astronomical artifacts such as Stonehenge have been found from ancient times. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics.

During the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of celestial objects, which is then analyzed using basic principles of physics. Theoretical astronomy is oriented towards the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the observational results, and observations being used to confirm theoretical results.

Amateur astronomers have contributed to many important astronomical discoveries, and astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena.

## Introduction:

Over the years I have done a lot of calculations when investigating how to construct different things. Normally you find at internet what you looking information for, but sometimes it could be comfortable to have your own calculations that you can adapt for your own purpose. Here are my collection of Excel files, maybe parts of it can be interested for you too? It's my personal and could be difficult for others to use. But I have clean them up, translated them to English and given a short tutorial to each of them down here. I'm not sure if this is useful for others, but if you find it interesting, take a look.

Take a look behind the equations and learn how it's calculated and maybe find if I had done something wrong.

At bottom you can download the file which have all this equations under different maps at bottom of the Excel sheet.

Page best viewed with screen set to 1024x768 or higher. The pictures that are labeled Lars Karlsson, text and web page designs are © Copyright 2002 - 2019 by Lars Karlsson. All rights reserved. They may not be reproduced, published, copied or transmitted in any form, including electronically on the Internet or World Wide Web, without written permission of the author.

## Astronomy (ASTR)

This course surveys observations, theories, and methods of modern astronomy. The course is predominantly for non-science majors, aiming to provide a conceptual understanding of the universe and the basic physics that governs it. Due to the broad coverage of this course, the specific topics and concepts treated may vary. Commonly presented subjects include the general movements of the sky and history of astronomy, followed by an introduction to basic physics concepts like Newton’s and Kepler’s laws of motion. The course may also provide modern details and facts about celestial bodies in our solar system, as well as differentiation between them: Terrestrial and Jovian planets, exoplanets, the practical meaning of “dwarf planets”, asteroids, comets, and Kuiper Belt and Trans-Neptunian Objects. Beyond this we may study stars and galaxies, star clusters, nebulae, black holes, clusters of galaxies and dark matter. Finally, we may study cosmology, the structure and history of the universe.

Meets New Mexico General Education Curriculum Area 3: Physical and Natural Sciences.

Includes hands-on exercises that work to reinforce concepts covered in the lecture, and may include additional components that introduce students to the night sky. Two hours lab.

Meets New Mexico General Education Curriculum Area 3: Physical and Natural Sciences.

1996. Topics [Selected Topics]. (1-6, no limit Δ [3, may be repeated three times Δ])

An introductory course covering the basics of the night sky, relevant physics, and the Solar System. The level of math is trigonometry and pre-calculus. First of a two-semester sequence.

Prerequisite: MATH 1230 or MATH 1250 or MATH 1512.

Pre- or corequisite: PHYS 1230 or PHYS 1310.

Students learn how to carry out astronomical observations using actual telescopes. Students learn the basics of the celestial sphere, telescope design and characteristics planning observations, astronomical data reduction, how to make measurements from astronomical data, interpreting results, and writing reports. The topics of the lab are aligned with 2110. The level of math is trigonometry and pre-calculus. Three hours lab.

An introductory course covering the Sun, stars, the Milky Way, galaxies and cosmology. The level of math is trigonometry and pre-calculus. Second of a two-semester sequence.

Prerequisite: MATH 1230 or MATH 1250.

Pre- or corequisite: Any physics course numbered 1200 or higher.

Students learn how to carry out astronomical observations using actual telescopes. Students learn the basics of the celestial sphere, telescope design and characteristics planning observations, astronomical data reduction, how to make measurements from astronomical data, interpreting results, and writing reports. The topics of the lab are aligned with 2115. Three hours lab.

Gravitation, radiation, relativity, stellar atmospheres, structure, and evolution.

Applications of advanced astrophysical concepts to the interstellar medium, star formation, the Milky Way, external galaxies, and cosmology.

Principles of optics and quantum physics applied to modern astronomical instrumentation (over a wide range of electromagnetic wavelengths), data acquisition and processing.

Planetary physics planetary investigation using space vehicles optical properties of planetary atmospheres.

*455. Problems. (1-3 to a maximum of 6 Δ)

Independent studies course for students seeking departmental honors.

Principles of optics and quantum physics applied to modern astronomical instrumentation (over a wide range of electromagnetic wavelengths), data acquisition and processing.

Astrophysical problems illustrating E&M and classical/statistical mechanics: expansion of the universe dark matter big-bang nucleosynthesis stellar interiors neutron stars supernovae. May be repeated when topics are different.

Astrophysical problems as illustrations of quantum mechanics: atoms molecules spectral lines ionized regions surrounding stars centers of active galaxies Lyman-alpha forest. May be repeated when topics are different.

Applications of advanced astrophysical concepts to the interstellar medium, star formation, the Milky Way, external galaxies, and cosmology.

## 2021 - 2022 CatalogCourse Descriptions for Physics/Astronomy

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Prerequisite Required: MATH 1314 and MATH 1316 or MATH 2412.
Course Description: The first semester of an algebra and trigonometry - based fundamentals of physics sequence. The principles and applications of classical mechanics and thermodynamics, including harmonic motion, mechanical waves and sound, physical systems, Newton’s Laws of Motion, and gravitation and other fundamental forces are studied with emphasis on problem solving. Laboratory experiments supporting the topics are included. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4008015303

### Course Title: College Physics II

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Prerequisite Required: PHYS 1401.
Course Description: The second semester of an algebra and trigonometry - based fundamental principles of physics sequence. The principles and applications of electricity and magnetism, including circuits, electrostatics, electromagnetism, waves, sound, light, optics, and modern physics topics are studied with emphasis on problem solving. Laboratory experiments supporting the topics are included. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4008015303

### Course Title: Stars and Galaxies

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Course Description: The study of stars, galaxies, and the universe outside our solar system. Introduces the properties of stars, stellar evolution, black holes, galaxies and current cosmological ideas. Emphasis is on the application of scientific principles and explanation of phenomena in the universe. The laboratory includes outdoor viewing sessions and the use of spectra. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4002015103

### Course Title: Solar System

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Course Description: Study of the sun and its solar system, including its origin. Introduction to the solar system and the historical development of astronomical ideas. Topics include the study of the celestial sphere, the planets and their satellites, the sun and other objects in the solar system. Emphasis is on the application of scientific principles and explanation of phenomena in the solar system. The laboratory includes outdoor viewing sessions, constellation identification and the use of telescopes. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4002015203

### Course Title: Elementary Physics I

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Course Description: Conceptual level survey of topics in Physics intended for liberal arts and other non-science majors. Topics include mechanics, energy conservation, atomic nature of matter and thermodynamics. The history of scientific developments and their impact on daily life are discussed. Also included are laboratory experiments that emphasize a conceptual understanding of Physics. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4008015103

### Course Title: Elementary Physics II

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Course Description: Conceptual level survey of topics in Physics intended for liberal arts and other non-science majors. Topics include wave motion, acoustics, electricity, magnetism, optics, relativity, atomic and nuclear physics. The history of scientific developments and their impact on daily life are discussed. Also included are laboratory experiments that emphasize a conceptual understanding of Physics. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4008015103

### Course Title: Physical Science I

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Course Description: Course designed for non-science majors, that surveys topics from physics, chemistry, geology, astronomy, and meteorology. It is a study of the basic principles and concepts of physics and chemistry, showing the relationship of these two sciences to the physical world at an introductory level. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4001015103

### Course Title: Physical Science II

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Course Description: This course is for non-science majors, that surveys topics from physics, chemistry, geology, astronomy and meteorology. It foucses on the interaction of physics and chemistry with the earth sciences and the physical world. Geology, astronomy, meteorology, and space science are emphasized. Selected principles and concepts are explored. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4001015103

### Course Title: University Physics I

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Prerequisite Required: MATH 2413.
Course Description: The first semester of calculus - based physics sequence for science, computer science, and engineering majors. The principles and applications of classical mechanics, including harmonic motion, physical systems and thermodynamics are studied with emphasis on problem solving. Performance of basic laboratory experiments supporting theoretical physics principles and applications of classical mechanics, including harmonic motion, physical systems and thermodynamics. Also includes experimental design, data collection and analysis, and preparation of laboratory reports. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4008015403

### Course Title: University Physics II

This is a Texas Common Course Number. This is a Dallas College Core Curriculum course.
Prerequisite Required: PHYS 2425 and MATH 2414.
Course Description: The second semester of calculus - based physics sequence for science, computer science, and engineering majors. Principles of electricity and magnetism, including circuits, electromagnetism, waves, sound, light, and optics are studied. Performance of basic laboratory experiments supporting theoretical physics principles and applications of electricity and magnetism, including circuits, electromagnetism, waves, sound, light, and optics. Also includes experimental design, data collection and analysis, and preparation of laboratory reports. (3 Lec., 3 Lab.)
Coordinating Board Academic Approval Number 4008015703

Designated by the Texas Higher Education Coordinating Board for general academic transfer among community, state, and technical colleges in Texas and state public four-year colleges and universities as freshman and sophomore general education courses.

WECM (Workforce Education Course Manual) Courses

Designated by the Texas Higher Education Coordinating Board as workforce education (technical) courses offered for credit and CEUs (Continuing Education Units). While these courses are designed to transfer among state community colleges, they are not designed to automatically transfer to public four-year colleges and universities.

## Basic celestial data - Astronomy

In time-domain astronomy, data gathered from the telescopes is usually represented in the form of light-curves. These are time series that show the brightness variation of an object through a period of time (for a visual representation see video below). Based on the variability characteristics of the light-curves, celestial objects can be classified into different groups (quasars, long period variables, eclipsing binaries, etc.) and consequently be studied in depth independently.

In order to characterize this variability, some of the existing methods use machine learning algorithms that build their decision on the light-curves features. Features, the topic of the following work, are numerical descriptors that aim to characterize and distinguish the different variability classes. They can go from basic statistical measures such as the mean or the standard deviation, to complex time-series characteristics such as the autocorrelation function.

In this document we present a library with a compilation of some of the existing light-curve features. The main goal is to create a collaborative and open tool where every user can characterize or analyze an astronomical photometric database while also contributing to the library by adding new features. However, it is important to highlight that this library is not restricted to the astronomical field and could also be applied to any kind of time series.

Our vision is to be capable of analyzing and comparing light-curves from all the available astronomical catalogs in a standard and universal way. This would facilitate and make more efficient tasks as modeling, classification, data cleaning, outlier detection and data analysis in general. Consequently, when studying light-curves, astronomers and data analysts would be on the same wavelength and would not have the necessity to find a way of comparing or matching different features. In order to achieve this goal, the library should be run in every existent survey (MACHO, EROS, OGLE, Catalina, Pan-STARRS, etc) and future surveys (LSST) and the results should be ideally shared in the same open way as this library.

## What is the basic difference between Astrophysics and Astronomy?

Astronomy is the study of the universe beyond the earth's atmosphere. The main branches are astrometry, celestial mechanics, and astrophysics.

Astrophysics is the branch of astronomy concerned with the physical processes associated with the celestial bodies and the intervening regions of space. It deals principally with the energy of stellar systems and the relation between this energy and the evolution of the system.

So, astronomy is sort of a top level science that covers any scientific explorations of space beyond our atmosphere and astrophysics is a branch of astronomy that is concerned with the actual physics of stars, planets, black-holes, etc. , their formation, evolution and ultimately their future.

For example, if you have a telescope in your backyard and you like to observe the night sky and make star charts and learn about our solar system then you are an amateur astronomer but if you like to use equations to calculate how big does a star have to be in order to become a black hole one day - well then you are an amateur astrophysicist.

'Watch the stars, and from them learn.
To the Master's honor all must turn,
Each in its track, without sound,
Forever tracing Newton's ground.'

## Sky Guide

Sky Guide is an astronomy app for sophisticated star enthusiasts and hobby astronomers who value well-founded and precise astronomical illustrations and data.

The basic app function displays a detailed, scalable and fully user-configurable celestial map with constellations and celestial objects (limit magnitude up to 6.3) that are visible with the naked eye or smaller telescopes. The place and time of observation as well as the direction of view can be manually configured by the user or automatically with the so-called “Live mode” (i.e. GPS, real-time and compass-guided).

Detailed additional information is available for every celestial object (fixed star, deep sky object, planet, moon, sun, meteorite shower). The information of the Bright Star Catalog and the Washington Double Star Catalog is made available for fixed stars. Additionally, users can add notes and links for every object.

The powerful search function makes it possible to align the map to a specific celestial object or guide the observer – in „live mode“ – to an object in the starry sky with specific notices. Searches can be performed according to the traditional name of an object, the catalog designation or the constellation. Moreover, the app makes it easy to identify celestial objects by aligning the device to the object in “Live mode”.

## Astro Notes: Astronomical Vignettes

Astro Notes are bits of information or tools that might be of use to amateur astronomers. They each cover a specific topic and are narrow in scope. They are produced by the Astronomical League as a service to our members. They may be copied and distributed freely as long as they are reproduced and distributed in their entirety with the Astronomical League cited as the source. The information contained in the Astro Notes is available from a variety of sources on the internet. Regional officers may make copies available at Regional Conventions with fees to cover their duplicating costs.

#### A - Safety Concerns

B - The Astronomical League Information

#### C2 - Determining Seeing Conditions

• An easy technique for determining how stable your skies are (seeing). This scale is acceptable for all AL Observing Programs.
• An easy technique for determining how clear (transparent) your skies are. This scale is acceptable for all AL Observing Programs.

#### C4 - Astronomical League Observing Programs

• This is an introduction to the Astronomical League's Observing Programs and Awards.
• To access the AL web pages for the Observing Programs, go to the Observing Program Website.

#### D - General Astronomical Information

The first three topics in this section deal with buying equipment for astronomical obsersving.

I create and teach all of the workshops in celestial navigation presently offered by ReedNavigation, including all online workshops. Although on-site classes are currently cancelled due to social distancing, I also teach all of the classes currently offered at Mystic Seaport Museum (MSM), as well as Boston Community Boating Inc. (CBI) and other venues. I am fluent in nearly every technique and tool in celestial navigation from ancient historical methods to the most modern computer-based applications, and I am the world's leading expert in the topic of lunars --the process of determining absolute time at sea by measuring with a sextant the angular distance between the Moon and the Sun (or a selected star or planet).

### General Background:

• StarTalk television: Celestial Navigation Expert
I was recently a guest, aboard as an expert in celestial navigation, on the December 3, 2017 episode of StarTalk, a science talk-show hosted by Neil deGrasse Tyson which airs on the National Geographic Channel (look for S4E10). The episode is also available for streaming (paid) on youtube, itunes, etc. Dava Sobel, author of "Longitude" also joined us in the studio for one segment.
• Developer, GPS Anti Spoof apps for Android and iOS
My "GPS Anti Spoof" app has been released for iOS and Android. The app does everything. Shoot the Sun (or Moon, planet, star) with your sextant and directly compare with the displayed altitude in the app. No calculations / no paperwork. It's great for sextant training --you get instant feedback. And it easily detects GPS spoofing, if you're worried about pirates and that sort of thing! Unlike nearly all other available apps and software, this app also incorporates the deflection of the vertical, which can throw off your sights by more than one minute of arc near many islands. The app is dead-on accurate. Details and download links: ReedNavigation.com/GPSantiSpoof/.
• Head Cartographer, Centennia Historical Atlas
The principal focus of my business, Clockwork Mapping, is the development and marketing of the Centennia Historical Atlas. The Centennia Atlas was, for over fifteen years, required course material for all students at the US Naval Academy at Annapolis, MD. Please visit HistoricalAtlas.com to learn more. My youtube channel has over 1.2 million views. Other videos, generally copyright-violating, based on my map animations have accumulated over fifteen million hits.
• Invited Whaleship Voyager
Celestial navigation expert on the 38th Voyage of Mystic Seaport's 1841 whaleship Charles W. Morgan, July 2014. Demonstrated historical celestial navigation techniques at sea off the coast of Massachusetts. Organized and operated 38Talk, an online community for discussions among Voyagers and others related to the 38th Voyage. Featured guest in live webcast from the deck of the Charles W. Morgan as we sailed among the whales on Stellwagen Bank north of Cape Cod, July 2014. I discussed the basics of "nautical astronomy" for an introductory audience: watch the video. I also appeared briefly on the CBS Evening News in their coverage of the 38th Voyage.
• Gravitation and Physics
I am an expert in gravitational physics including topics ranging from theoretical general relativity to practical tidal analysis. My thesis at Wesleyan University (Middletown, CT, 1984) was awarded High Honors, and I was also the winner of the Sherman Prize in Mathematics and the Bertman Prize in Physics. Read an article about me from Physics World magazine in their Once a Physicist column.
• Leap Second Conference
In October 2011, I presented a paper on celestial navigation and the issue of "leap seconds" at the conference on "Decoupling Civil Timekeeping from Earth Rotation" hosted at the headquarters of AGI near Philadelphia. I was the "small fry" non-academic among the world's experts in positional astronomy and the science of time-keeping including Dennis McCarthy, George Kaplan, and P. Kenneth Seidelmann among others. Neil deGrasse Tyson, television personality, host of the new Cosmos, and director of the Hayden Planetarium in New York City, also joined us as an interested guest. Here's a photo of us.
In addition to appearing recently on StarTalk television, I was a guest on Neil deGrasse Tyson's StarTalkRadio in 2012: StarTalkRadio: Time Lords and the Science of Keeping Time (to listen to my contributions, go to time stamps 12:09-14:50 and 24:20-25:35).
• Published article "Celestial Navigation and UTC"
On the significance of changes in 'leap second' procedures and its potential impact on traditional celestial navigation. Presented at conference in Exton, PA. October, 2011. Published in the Journal of the American Astronautical Society, 2012. Read the preprint.
• Interview on NPR's "Here and Now"
Discussing the future of celestial navigation and the recent announcement that some basic instruction in celestial navigation will once again be part of the curriculum at the US Naval Academy. October 2015. Listen here.
• "After Longitude", National Maritime Museum
In March 2012, I delivered two presentations on lunars at the "After Longitude" conference at the National Maritime Museum at Greenwich, UK (a few hundred yards from the Prime Meridian). One paper focused on the role of lunars in American commercial dominance in the Pacific in the 19th century, especially aboard whaling vessels. The second paper "Lunars in the Space Age" focused on modern use of lunars for position-finding in space. Lunars were shot during Apollo missions to the Moon, especially on the flight of Apollo 8, the first manned mission to reach lunar orbit.
• Susan P. Howell Memorial Lecture
In June 2004, I gave the Susan P. Howell Memorial Lecture on the topic of Lunars focusing on the use of lunars aboard the Boston trading vessel Reaper in 1809-1810. The logbook of this voyage is in the research collection at Mystic Seaport.
I have organized "Navigation Weekend" conferences in 2006, 2008, 2010 and 2017 bringing together navigation enthusiasts, scholars in the history of astronomy, and practical navigators to the Treworgy Planetarium at Mystic Seaport. I also did numerous presentations of my own at these conferences on lunars, the history of the Nautical Almanac, and other topics.
• Experience at Mystic Seaport
Though I am not on staff now, I've been employed by Mystic Seaport directly several times over the past couple of decades. I have presented over 3000 planetarium lectures there primarily focused on topics in celestial navigation.
• Management of NavList
I manage NavList, a community devoted to the history, modern practice, and future of celestial navigation and other forms of traditional position-finding. NavList began as an online community and our message boards continue as, by far, the most active arena for online discussions on these topics.
• Navigation Instructor, Physics Instructor: Northeast Maritime
I've recently taught several intensive two-week USCG licensing classes in celestial navigation at Northeast Maritime Institute in Fairhaven, Massachusetts. I am a USCG-approved instructor in celestial navigation. I also taught an introductory college level conceptual physics course at NMI during the Winter/Spring term of 2017.
• Editor, Pub.249 "Tables for Navigation"
I maintain the celestial navigation tables known as "publication 249", marketed commercially by Celestaire, Inc., which are used by thousands of vessels at sea as a backup method of celestial navigation. These tables list the altitudes and azimuths of stars during twilight enabling quick and easy sight reduction. The tables in volume 1 are updated every five years. I manage the complete update process including collecting data from official USNO sources and validating that data by independent calculation of each of over 400,000 numbers, and I also produce and edit the pdf from which the printed book is published.
• Invited Planetarium Lecturer, Wickware Planetarium
During the fall of 2016, I presented two special hour-long planetarium programs at the Wickware Planetarium, Eastern Connecticut State University in Windham, Connecticut focused on topics in celestial navigation. These were unique, live programs written and developed specifically for these events.