John in a blue hat MenkeScientific

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John's Page

This page offers links to John's scientific interests and various files you can view or download.  Click on a category below to see a list of what's available.  Hint:  we usually add the newest files to the bottom of each list.

Astronomy Images

Below are some images from the many thousands that I've done over recent years.  Because I work mostly on asteriod light curves, much of my imaging is "boring", i.e., I take hundreds of images a night of the same stars to look for variations in their brightness.  Those images may not be pretty, but the curve that results is! 

On the other hand, as a change of pace, I often image planets, the moon, or interesting galaxies and nebulae -- I've included a selection to share here.  I should note that they do not represent "state of the art" for amateur work: many amateurs specialize in imaging, and with better equipment, locations, and skill, their work aproaches professional levels.  My goal is not perfection but rather the joy of seeing what's there and gradual improvement in my technique.


M82 taken 1/21/2000.  f12 4600 seconds, MaxEnt and DDP processed.  Shows apparent star/supernova?.
M82 taken 1/7/2001 f12 13x10min, MaxEnt and DDP processed.  Star/supernova missing.

Mare Nectaris area.  This shows the many small craters in the area.  See if you can spot the DHCs mentioned below.
m82 old Dark Haloed Lunar Craters (DHC).  The moon has several dozen small craters that are surrounded by darker material.  Not much is known about the cause of the dark material; however, volcanic emission seems to be one of the leading theories.  After stumbling onto a pair of these in Mare Nectaris, I have been studying the contrast under different lighting conditions to gain some additional insight.  The relatively poor seeing in our mid-Atlantic area, and the small refractor, make this study at the edge of feasibility.  Here is a  picture of the area, somewhat enhanced. Theopholis (75 km dia) is the large crater at the bottom of the picture.  The upper DHC is about 3 miles in diameter, the lower one is about half that, and not easy to see under this lighting.
M57. Stimulated by the excellent picture on the right by a well known astrophotographer,  I took the picture on the left with my 6 inch.  Clearly the right hand picture is better, but the left hand shows that with effort you can still do good work with a small scope.  Exposure was about 2 hours.
M31, The Great Galaxy in Andromeda.  This is a group of three exposures  with 20 min. exposures at f4.  The mosaic was put together using MaximDL (first attempt).  With heavier processing, one can bring out more of the central region, if desired.
Click for image of comet
Comet 2002 (Ikeya-Zha). UL Comet on June 9, 2000 shows some faint anti-tail to the right.  To show the tails more clearly, I averaged 16 comet images each rotated 22.5 deg, then subtracted from the original giving UR image.  On Jun 21, in strong moonlight, I took 30x1 min exp, median combined.  The comet has about half its former brightness.   Background moonlight is about 9x the background of the June 9 image.  Even so, with no processing, one sees a much sharper and relatively brighter anti-tail to the west (right, sunward) as we pass through the plane of the sun-comet-earth.  In the one minute exposures, the anti-tail is about 10 counts out of about 2000 background, the comet nucleus is about 500 counts above background.
Mars, taken August 24, 2003.  Black and white image compared to a drawing done a few days earlier.  (Please read the text below images for more details.)
Images of Mars on August 25, 2003.  Color vs. back and white. (See text below images for further description.)


Light Curve Measurements - asteroids and variable stars

Most asteroids are not perfect spheres, so as they rotate, their oblong shapes reflect different amounts of sunlight back to us.  Thus, even though we cannot actually see an asteroid, we can measure its reflected light, and this allows us to infer its rotation time.  Amateurs take the lead in this work, and many of us measure scores of asteroid light curves each year.  Not only are asteroid rotation rates interesting in themselves (why not faster?  why not slower?), after several years of measurements, it is often possible to use the data to infer the actual shape of the asteroid. 

I show below a small sample of the asteroids I have measured.  The results have been published in Minor Planet Bulletin.  I have also written papers on some of the techniques used in this work. 

My work on light curves of variable stars follows the asteroid list.



1116 Catriona
My first asteroid lightcurve measurement. I was so-o-o-o green, but even a rank amateur with persistence can achieve useful results.
27496 (no name)
A faint asteroid, also one of my first.  The results are not very trustworthy.
1016 Anitra
Bright, fast, easy, fun!
808 Merxia
A bright asteroid, a beautiful curve.
471 Papagena
A fast rotator, bright.
582 Olympia
Moderately bright object with a 72-hour rotation, making this VERY difficult.  Multiple observers have worked on Olympia.
2283 Bunke
Faint (nearly 15 mag) but fast (4 hours).  It pushed my skills and equipment to the limit.                     

This paper reports observations of the near earth asteroid 2010 AL30, discovered in January 2010 only days before it passed by our planet.  I include a light curve and discussion of measurements.
(PDF file, 373K)      

Below are measurements of selected variable stars.  Some variables produce light curves that look similar to asteroid light curves, but of course, there is considerably more to variables than that. The best source of information about variable stars is AAVSO, the American Association of Variable Star Observers, based in Cambridge, MA.  Despite its name, AAVSO is a worldwide organization.  It maintains a significant archive of observation data and collects new observations that it makes accessible through the AAVSO International Database.  The first paper listed below describes a highly unusual variable that AAVSO began targeting for more data in March 2009.

Variable Star

A cataclysmic variable star with very fast eclipses.  Observations taken in May 2009.
(PDF file, 188K)                             
"A Neophyte's Determination of EY Ceph Curves and Orbital Constants" (PDF file, 185K).
This paper was presented in May, 2002 at a meeting of the International Amateur-Professional Photoelectric Photometry-Western Wing (IAPPP) in Big Bear, California.  It describes intitial measurements of the EY Cephius eclipsing binary system.             
U Sco Monitoring
"Monitoring U Sco"
(PDF file, 657K)
U Sco is a recurrent nova with about ten years interval. Predictions have been made that  a new eruption is imminent. Monitoring the star is difficult because it is faint (18th magnitude), low in our southern sky, and has a very close field star.  This paper discusses how I handled the measurement challenges.                                                           


Asteroid Occultations

Asteroids, of course, move through space in their orbits.  As they travel, they sometimes pass in front of stars we can see, thus eclipsing the star and casting a shadow onto the earth.  These events can be predicted, with the paths and timing of the shadow path on the earth accurate to a few tens of miles and tens of seconds.  If one or several people set up observing stations across the path of the shadow, and if they measure the duration of the eclipse, then it's possible to calcualte the size and shape of the asteroid.  This work can be done either from a fixed observatory, or from portable equipment.  This is a very active field of study, with excellent resources on the web

As of early 2009, I have attempted about thirty occultation events: weather wiped out about twenty of them.  Half the remainder failed due to equipment problems or my human error.  The other half were successful, but in most cases, the shadow did not pass over the telescope, so the result was a "miss" (this is often a very important observation).  In one case, I had a "hit".  This record of results sounds worse than it is: as my skills improve, I will see more "hits".  Here are three files that explain occultation observing in more detail.


Asteroid Occultation Observations
A power point presentation on the addictive nature of observing asteroid occultations.  I made this presentation at the 2009 meeting of The Society for Astronomical Sciences (SAS) in Big Bear, CA.  It is a presentation version of the paper listed below. (Note the movie on slide 17 won't play, but I've posted it on YouTube.)
(PDF file, 16.9M)
The Addictive Properties of Occultations
Paper written for and published by the Society for Astronomical Sciences (SAS).  It was one of a pair of papers on this topic at the annual meeting of SAS, held in Big Bear, CA in May 2009.
(PDF file, 7M)                                                                                                                        
Detecting Occultations Buried in Noise
This paper describes using Excel software techniques to determine whether an occultation signal is present in noisy data.  Both real and pseudo-data are used as examples.
(PDF file, 511K) 



Here are a few spectral studies of comets.  More to come. I've also created an online archive of spectral images for objects other than comets  I invite you to read the paper on the techniques and the set-up I use when doing spectra. 

9P/Tempel1 Spectrum

"Spectrum of Tempel1"
(PDF file, 40K)
Spectrum taken on July 2, 2005 using DSS7 Spectrometer.  Very poor signal to noise, but the comet was faint: an interesting first try.  See below for better results.

Spectroscopy Techniques

"Spectroscopy Techniques".
(PDF file, 551K)
This paper describes my earliest setup using a C11 and DSS7/402 combination to observe astronomical spectra.  I also discuss briefly some of the challenges of the operations, as well as corrections needed to make the spectra useful.  Current techniques are described below.

Spectroscopy Techniques

"Spectroscopy Methods Summary"
(PDF file,  692K)
This paper, written in Fall, 2010, describes my current observation and analysis methods using the 18-inch Newtonian and DSS-7, controlled by custom software.  I no longer use the C-11 for spectroscopy because I need all the photons I can get!

Spectroscopy Techniques

"Spectroscopy Processing: The Video"
(AVI file, 76M)
This 30-minute video shows how I use MaximDL and Excel to process sprectroscopic images and convert the data to graphical output.  The video demonstrates techniques described in the paper "Spectroscopy Methods Summary", above.

Examples of Spectra, v.3

"Examples of Spectra". 
(PDF file, 1.1M)
This paper gives some of my spectroscopic observations of various objects, including M57, and Comets C073 and Comet Swan. 
Comet 17P Holmes - Spectra

Comet 17P Holmes - Spectra and Images
(PDF file, 1.5M)
Images and spectra of Comet Holmes - through November 29, 2007

Comet 17P Holmes - Coma

Comet 17P Holmes Coma Study
(PDF file, 800K)
An analysis of the coma density, including models and measurements of transparency during the first eleven days after outburst.

Comet Lulin

Spectrum of Comet Lulin, taken February 23, 2009, with comparison to Comet Swan spectrum.
(PDF file, 478 K)
Nova Scorpii 2011

Spectra and photometry of this nova discovered June 1, 2011 by John Seach in Australia.  My spectra were the earliest taken and submitted to AAVSO following the discovery of the nova.
(PDF file, 376K)


Here is an update on Nova Scorpii 2011:  this paper, written in September 2011, presents more light curves, more spectra.  The nova is now officially designated as V1312Sco, a new name to go with new data.
(PDF file, 1.8M)

AZ Cas pdf
AZ Cas ppt

AZCas is an eclipsing variable encompassing a cool M star and a hot B star.  The system shows occasional events lasting hours to days.  The pdf document describes the work to date, while the power point contains JPGs of all the spectra to date.  Each file is under 1MB in size.


Astronomy Equipment and Software

One of my great loves is working in the shop, taking an idea for a new elelctronic device or observing tool or software program from concept to reality.  I also enjoy solving problems with equipment I'm using, or analyzing why some products work the way I expect them to, but some don't. 

Here is a selection of papers on equipment related subjects.  These include descriptions of equipment, evaluation of various designs or products, better methods of making particular measurements, how I built the 18-inch telescope, etc. Enjoy!


"Are Flats Really Flat?" 
(PDF file, 42K).
I discovered a characteristic of the ST7E camera in which internal reflections in the camera can create a 2% gradient in the flat.  Use of the flat for calibration can then introduce an error when performing high precision photomertic analysis.  We show that a simple mask can prevent this effect. 
C11 Mirror Flop
"C11 Upgrade"
(PDF file, 20K)
Although the optics of the C11 were excellent, I was experiencing image shift as the scope moved to different positions. I modified the mirror cell of the scope to reduce mirror flop.  This paper describes the results.

More on Flats
"Just How Good are Flats?"
(PDF file, 987K)
This paper reports research done on flats used in CCD Photometry.  I measured how well different types of flats could, in fact, correct an image.  The work shows how to separate out the effects of camera, optics, and flat source.  This PDF is the first half of a paper given at the 2005 meeting of the Society for Astronomical Science, and is copyrighted by SAS.  The complete original paper can be retrieved at

"StarZap: A Method of Removing Unwanted Stars"
(PDF file, 39K)
StarZap is an automated program that can remove stars that interfere with the measurement of asteroid brightness.  The program uses tools available in MaximDL. This PDF (with slight modifications) is the second half of the paper described above.  The program and source code (VB6) are open source and available free.  Click here to download the installation zip file, which includes an essential "READ ME" file.   

Spectroscopy Techniques
"Spectroscopy Techniques".
(PDF file, 551K)
This paper describes my setup using a C11 and DSS7/402 combination to observe astronomical spectra.  I also discuss briefly some of the challenges of the operations, as well as corrections needed to make the spectra useful.

Drift Scan-o-meter

Drift Scan-o-meter
(PDF file, 884K)
A new method of performing a drift scan to measure asteroid occultations.

Flats Revisited

Flat Errors Are Not the Problelm
(PDF file, 377K)
Demonstrating how some "huge errors" in a flat source can sometimes make no difference.  Surpirse!

18-inch, f3.5 Newtonian

Fast Newtonian Scope for Photometry and Imaging
(PDF file, 8.6M)
This paper describes construction, testing and operation of an 18-inch f3.5 Newtonian telescope, brought into service in 2007.

Remote Scope Cover

Remote Operated Scope Cover System
(PDF file, 1.3M)
onstruction of a remotely operated telescope cover (for the scope described above) and associated electronics.

Comparing Video Cameras
How effective are new, more sensitive video cameras for occultation measurements?  This paper reports my findings when I compared four cameras in six tests.  Results suggest that the increased sensitivity in some models is more usesful than in others. 
(PDF file, 4.4 M)

Mintron Camera Timing Logic
The Mintron is a video camera with integrating capability.  This paper describes a study that explores the timing logic when the camera is used in integrating mode.  My results show that the integration mode causes a substantial delay in the output signal but no other delays.  This finding is relevant when determining uncertainties in timing occultation and similar astronomical events.
(PDF file, 1.4 M)

This paper describes construction and testing of an instrument for fast photometry.  The instrument has been tested both on the bench and with stars.  Paper includes photos and schematic.
(PDF file, 4.1M)

This paper describes how to extend the long wavelength limit of the DSS7 from the usual 7500A to >9000A.  Using an ST7 or ST402 requires a simple modification, while an ST1603 requires none.  The paper also describes my DSS7 Control Program, available as a free download here for your experimentation.
(PDF file, 1M)

Fast Spectrometer

In 2011-12, I built a spectrometer to match the optical characteristics of my 18-inch, f3.5 Newtonian telescope (described above).  This paper shares the steps in design, construction and initial testing of the "FS-1".
(PDF file, 5.6M)

Fast Spectrometer

Here is the paper I presented at the May 2012 meeting of the Society for Astronomical Sciences in Big Bear, CA.   It describes observations that demonstrate some of the capabilities of the instrument.
(PDF file, 2.8M)

Research with Fast
The paper describes two projects: (1) researching the RV curve of the pulsating star BWVul for an RV signal of a faint star, and (2) compiling the full 1.2-day spectroscopic signal of SigOriE, a B emission star.  I presented these results at the May 2013 meeting of the Society for Astronomical Sciences, Big Bear CA.
(PDF file, 1.1M)

Spectrometer Wavelength Calibrator
In summer 2013, I constructed a wavelength calibrator for use with the fast spectrometer described above.  The calibrator uses small ampoules of gas excited externally from a 12V:2KV power supply, all at a cost of about $100.
(PDF file, 3.2M)


Papers on topics other than astronomy

The world has other challenges besides understanding the universe.  I've given much thought recently to Global Warming and related non-astronomy issues.

 Can Global Warming be Stopped?  This Power Point presentation outlines a very pessimistic (but realistic) view of our future ability to cope with global warming.
(PDF file, 1.1M)

A Heretic's View of the 7th Principle
This is a lay sermon that analyzes the Unitarian-Universalist 7th Principle (concerning the interconnected web of existence) from a very different point of view than is common.  The sermon discusses global warming as a major example.
(PDF file, 140 K)

This paper analyzes energy sources that could substitute for fossil fuel.  The conclusion is that only nuclear electricity and conservation can meet the major needs of the world in the short (40year) time available.
(PDF file, 116 K)

Global Warming:  Poppycock???
This paper is targeted at readers who are reluctant to accept that global warming is real.  It confronts some of the current claims that scientists are wrong about global warming.
(PDF file, 316K)

Tee Shirt Flipping Study
This paper explores the long-standing question of what makes clothes turn inside out in washing machines.  Data collected during 2009 reveal a 30% flipping rate. 
(PDF file, 1.7M)

The small Sentry Firesafe in the office of a volunteer organization would not open due to a stuck handle.  I brought it home to investigate.  This paper describes (with photos) how the safe works and suggests maintenance that may be needed.
(PDF file, 8M)

One lucky day, I found a 1978 Motron moped on a pile of discards.  I invested a modest amount of  time and money restoring it to operating condition. This paper describes my moped adventures with text and photos and explains why I chose to "soup it up" for fun and safety.
(PDF file, 13M)