The following chapter is an unedited (with extras not in the book) reproduction with permission from Collins Foundation Press and Scott Degenhardt from the book Small Telescope and Astronomical Research that was released in 2009. It was written with contributions by those who presented or attended the 1'st annual Galileo's Legacy Conference celebrating the International Year of Astronomy 2009, the 400'th anniversary of Galileo turning the telescope to the heavens.

smiey face presentation



Effects of Optical Miniaturization on Occultations

By Scott Degenhardt (



We live in the dark….. 3

Heavenly bodies passing in the night. 3

Your thumb at arms length. 4

Stars gone wild?. 5

Hold still while I take your measurement!. 5

Can you point me in the right direction?. 6

OUT… IN!!!. 7

Smile for the camera. 7

Chords in harmony. 7

My “small” endeavor. 10

So what do I really need?. 11

More power to ya’ 13

How low can I go?!. 14

What’s drivin’ you?. 15

Galileo makes a return. 16

Greedy, aren’t I?. 19

How do I make me one of them there Minis?. 22

That feeling of completeness. 29

Stamp & Run. 30

Deploy & Run. 31

Bottom Line, what good has it done?. 33

In Conclusion. 38

Ya’ wanna know more?. 39

References: 40

And the Kudos go to…. 41

Scotty’s Bio. 41


Figure01 Mighty Mini PC164CEX-2 Owl FR

Figure 1: The “Mighty Mini” at 50mm in objective aperture is creating quite the revolution in asteroidal and lunar occultation measurements.

We live in the dark…

Unlike most endeavors of astronomy, where the goal is to gather as much light as possible for an image or a measurement, we occultationalists like to collect shadows! We are often referred to as “those guys that hide in the dark.” We set up telescopes and watch stars, hoping that the star will disappear as a celestial object passes in front of it. This entire science is well documented in the book Chasing the Shadow by Richard Nugent (

            According to the New Oxford American Dictionary the word occultation originated in the 15th century from the Latin verb “occultare”, meaning “secret”, based on “celare” which is “to hide”. It does sound as if we are quite the “shady” characters. It’s no wonder, when we knock on someone’s door and ask, “May I use your property to time an occultation?” that their facial expressions reveal mental pictures of masked menaces chanting in a circle with shrunken skulls and flaming tiki torches! So most times when approaching a property owner for permission to view an event from their ideally placed proximity, we describe it as an exciting eclipsing event instead, much more palatable.

Heavenly bodies passing in the night

           These celestial synchronicities where one object passes in front of another have been noted by man for many many centuries. David Dunham, President of the International Occultation Timing Association (IOTA), tells me documentation of occultations have been found all the way back to early B.C. times.  Aristotle observed the reappearance of the planet Mars on April 4, 357 B.C. and concluded that the Moon must be closer to the Earth than Mars. In fact, in Aristotle’s writings, On the Heavens, he refers to the Egyptians and the Babylonians observing occultations many years prior.

            Galileo Galilei certainly observed occultations, as is apparent by his engravings and other documents. He was not known for timing them accurately, but his depictions of them were published in his Sidereus Nuncius. Dave Herald of Canberra, Australia, who maintains the database of lunar and asteroidal occultations, confirmed that the reappearance of theta Librae on January 19, 1610, depicted in one of those engravings, matches our software prediction and rendering for Padua, Italy at 05:44:16 UT.  

Figure02 F7

Figure 2: Drawing ID F7 from Sidereus Nuncius depicting his view of the reappearance of theta Librae. (courtesy Galileo's Lunar Observations and the Dating of the Composition of SidereusNuncius , Whitaker, Ewan A., Journal for the History of Astronomy, Vol. 9, p.155)

Your thumb at arms length

Today we still use the moon as a yardstick during solar eclipses to measure the size of the sun. Baily’s Beads are a “side effect” of the sun’s light shining through the valleys of the moon’s poles during solar eclipses. This solar diameter measurement is made accurate by calibrating the lunar limb shape through lunar grazing occultations. Our Moon's equator is so close to the ecliptic, within 1.5 degrees, that the polar regions are never sunlit well enough to map in the normal way using sunlight, preventing accurate maps derived from photographic surveying. Accurate timings of multiple disappearances and reappearances of stars through the lunar polar regions is the best way to survey in the dark the lunar polar region that creates the Baily’s Bead visual effect.


Figure03 Lunar Graze Profile

Figure 3: Lunar profile from the graze of delta Cancri on May 9/10, 1981. (courtesy David Dunham)

Stars gone wild?

           On January 1, 1801 Italian astronomer Giusappe Piazzi discovered a star that was moving. He first thought it was a comet, but later determined it had a uniform orbit between Mars and Jupiter. It turned out to be asteroid #1 and inherited the Roman goddess’s name Ceres. This started a new database of celestial objects: minor planets or asteroids. Since then the number has risen to around 190,000. For many decades predicting the orbits of these rocks was very uncertain. It wasn’t until 1961 that a prediction of an asteroid passing in front of a star was successfully confirmed by the observation of (2) Pallas recorded photoelectrically at Naini Tal Observatory in India. The position of the stars in the sky was just as much to blame for the uncertainty in asteroidal occultation prediction. In the mid to late 1970s accurate star catalogs were finally being produced, and then the Hipparcos catalog became the crème de la crème for asteroid occultation predictions. Modern mathematics and good star catalogs now allow us to predict with a calculable uncertainty the occultation of stars by these minor planets. This enables us to remotely perform measurements of these bodies by measuring the shadow they cast on the earth during occultations of stars.

Hold still while I take your measurement!

According to Dave Herald, the primary goal of asteroid occultation measurements is to accurately measure their size and shape. The secondary goal is to provide astrometric updates of their positions to improve the orbital elements used to calculate their motions. Using GPS signals, we can enable video time generation devices such as a KIWI OSD to lay Universal Time stamps on video recordings of occultations of stars by asteroids. We can use this same GPS array to measure our observing position on the Earth to better than 15 meter accuracy. Given the NTSC video image rate of 59.94 fields per second and the positional accuracies of the observation, we are capable of measuring asteroid features on the order of 10s to 100s of meters, several orders of magnitude above visual observations done with even the largest of earthbound telescopes using adaptive optics such as Keck.


Figure04resolution compare

Figure 4: A mathematical comparison of the resolution of the Keck adaptive optics in 2008 compared to an occultation of (216) Kleopatra on September 26’th, 2008.

Can you point me in the right direction?

           There are many good sources for the prediction of lunar and asteroidal occultations. Dave Herald’s Occult 4 is the current standard for us at IOTA. Both predictions and reductions of observations are maintained with this software. OccultWatcher 3.1 (OW) by Hristo Pavlov will create a table of custom predictions for your observing location and desired parameters. OW also is used by observers as a centralized database for coordinating event planning. In OW, each observer posts his/her intended viewing location and then all viewers can see where others are placed along the shadow path to prevent two people from observing on the same chord. Numerous prediction pages are kept current on the Internet. Some pages even have very handy interactive Google maps with satellite and terrain images for remote site observation planning. Links for these are provided at the end of this chapter.

OUT… IN!!!

           So, with predictions easy to acquire, all that’s missing is observers. Now we get to the crux of the situation, the number of observers, i.e. the number of measurements or chords for each asteroid event. Chances are that if you are interested in observing this type of celestial event, you already own a telescope. If that is the case, you are only one shortwave radio and tape recorder away from performing an occultation timing and contributing to this important database of measurements. You can observe an occultation visually and, with a tape recorder, call out the disappearance and then the reappearance, while also recording the WWV broadcast time signal of Coordinated Universal Time. This is very low-cost, and helpful. However, the accuracy of this timing isn’t as accurate as the video method.

Smile for the camera

           Recent advances in super-sensitive video cameras used security have enabled video documentation of occultation timings and boosted the potential from the sometimes up to one second of uncertainty for visual timings to 0.017 seconds for NTSC format video. There are a number of different video camera models available, depending on your main focus of observing, but two of the most common cameras used today are the latest model PC164C by Supercircuits (automatic gain and shutter) and the WAT-902 series (fully manual gain and shutter) cameras, which offer limiting magnitudes of around 12th magnitude in the average-sized backyard telescope. Recording devices such as digital recorders offer high quality playback for the cleanest observation reduction. Hand held digital camcorders such as the Canon ZR Models ZR10 through ZR300 have analog input capabilities, 2 hour tape capacity, and 5 hour life batteries, giving the remote observer a 1 pound, highly reliable recording device. The KIWI OSD video time stamping device uses a common Garmin GPS receiver to place on the recorded video the correct UT time to an accuracy of +/-1ms.

Chords in harmony

           With predictions, equipment, and planning software readily available to the average backyard observer, all that is needed is the observer and some coordinated efforts. The most popular method until recently was one person manning one scope, either at their home or at a remote location more optimal for the shadow’s path. While any and all observations are certainly welcome and needed, there is a limit to the information that can be gained by single-observer events. It is exciting for the one observer who saw the star wink out briefly, but the data is ambiguous. What part of the asteroid did you transect? Is the rest of the body to the left or the right of that chord? A single chord tells you nothing about the overall shape of the rock. Two well placed chords through a body begin to set some boundaries as to size and location of the center of the body. Both the astrometric position and a generalized idea of shape are detected in the reduction.


FigA1 single chord
FigA2 single chord
FigA3 double chord
Figure A shows a single chord doesn't define shape nor position, a single chord with a miss puts some constraints, but two chords well placed give good approximations of shape and position.


Dave Herald has frequently preached the point for more than one chord for each event being an important goal, and David Dunham has been the “spokesperson” for years trying to get IOTA observers to attempt running one extra observing station if possible. David’s basic ideal premise is to set up one observing station at your home and then travel a bit to set up a second attended station for the second chord. The miniaturization of electronic equipment in the past decade is making this endeavor a much easier task to perform. But it has taken a while for this type of observing to catch on. 

My “small” endeavor

           After almost a decade of not doing any astronomy at all, I decided to get back into occultation timing again and renewed my IOTA dues. On November 3, 2007 I made my first occultation timing, a lunar graze of the bright star Regulus. Figure 5 is a photograph I took of my setup in action. This expedition for me was a major milestone for me. I was able to take all of my equipment that I would normally run in my back yard using power outlets from my house and successfully remotely record an event completely power line free. But the extreme amount of “stuff” needed to make this observation suggested there had to be a better way. I needed less, not more, things, and the size of the things needed to be smaller. I simply could not practically lug a car battery around to run DC to AC inverters to power my recording device. I had to use something smaller than a lawn and garden battery to run my monitors and cameras. I had to figure out what I didn’t need and improve on what I did need.

Figure05 20071103 Regulus setup

Figure 5. My remote setup for a single station observation on November 3, 2007.

So what do I really need?

           As I tried to deploy more than one station for an event, several obstacles stood in the way, including the equipment itself. One by one I examined each necessary piece of equipment needed for accurate occultation timing and then searched for the best, most reliable, and smallest version. The list of absolute necessities is:


·         An optical instrument

·         A mount for the optical instrument

·         Precision star charts for pre-pointing the optical instrument to the part of sky where the predicted occultation will occur

·         A camera for the optical instrument to image on

·         A monitor for pre-pointing the optical instrument using the charts

·         A recording device to store the detector output

·         A long life power supply for a camera and recording device

·         Environmental containers to keep the camera and batteries warm and dry


            Assessing this list in order of what took up the most weight and volume, I found there was a tie between the recording device and the optical instrument. The recording device was much easier to deal with first. I was using a home VHS VCR that needed a car battery to have enough reserve to run an AC to DC inverter that provided 110VAC through many feet of extension cord for several hours. This VCR was in a very large Baskin Robbins thermal case made to keep ice cream cakes cold (used to keep the VCR warm). A good friend of mine, Tammy Woods, had a Canon ZR10 camcorder that I had once borrowed for some video work. I noticed that it conveniently had a composite video input. This could feasibly replace my entire 50-pound (or more) recording setup with a self-powered, one-pound device — and as a bonus, a device that records digitally. It only took one observing run to show me that the Canon ZR model camcorders were my recorder of choice.

Figure06 ms dollar chart

Figure 6. A statistical analysis of the millisecond time accuracy achievable multiplied by the $ per device. It’s very interesting to note that a $20 tape recorder with a $50 SW radio actually ranks over 20K ms$ due to the average 0.3 second accuracy associated with visual timings. MDVR remains blank due to no statistical timing analysis done at the time of publishing of this chart but is a valid remote recording option.

More power to ya’

After solving the recorder issue, I attacked the battery used for providing power. I know from experience with other electronic devices that both the Lithium Ion and the Nickel Metal Hydride (NiMH) offer the lightest weight with the highest amount of reserve power. Lithium rechargeable batteries are a bit pricier than NiMH, so I first bought a few dozen NiMH battery packs and tested them and found them to be very practical, very reliable, and easy to find on the market. I then filled my observing arsenal with many packs of Duracel 2650mAH NiMH AA batteries. I ran numerous tests to try to run down the battery pack and found that I could get more than a dozen hours of current to run our common video camera. I also found the Canon ZR camera had an optional BP-522 high capacity battery available as an accessory. This battery has 5 hours of lifetime compared to the just over 1 hour of the standard ZR battery. Thus the long lifetime power in a miniature pack issue was solved.


FigureB Duracell 2650mAh discharge test

Figure B. A discharge test of my NiMH cell battery pack consisting of 9 AA Duracell 2650mAh batteries gives me more than a dozen hours of power.


How low can I go?!

           Things were shrinking fast now! The only major piece that needed attention was the optical instrument. The problems here were not only the size of the 6” f/8 Newtonian, but the fork mount that had a stepper motor clock drive, which required yet another lawn and garden battery to drive the worm gear. It would be nice to have a smaller mount, something like a camera tripod that was collapsible, and this would then eliminate the clock drive, thus eliminating yet another large battery I had to drag around to all remote viewings. But how could I logically eliminate the clock drive…? How about replacing it with the most accurate and consistent rotating mechanism available to man, the Earth’s rotation!

What’s drivin’ you?

           Just suppose I was able to point ahead of time my optical instrument to the exact area of the sky where the occultation might occur many minutes or hours later. If I knew how to readily determine this location and aim in that area I would be able to use the Earth as my clock drive, allowing its rotation to bring the target star in view of the telescope and camera at precisely the predicted moment the event was to take place. This would eliminate the need for any clock drive at all. So, using Guide 8, I started manually plotting a line from the event time target star backwards in time, showing where the altitude and azimuth of the event would be at any given time that I might arrive at my planned observing sites. This new method worked flawlessly, but it was a bit unwieldy to generate the charts. It would take several hours to create enough charts for a single event. I had the thought that since an animation feature already existed in Guide 8.0, with which one can create a labeled track for other celestial objects, it might be easy to add one more to this function, to track the alt-azimuth of an object and place time tick marks on the sky chart that lead back to event time. I made a request to Bill Gray, author of Guide 8.0, if such an upgrade to his software were possible, thus automating my manual method. Bill wrote back almost overnight with an easy upgrade to his Guide 8 that converted my several-hour plotting method to 2 minutes of work, and now several of us use this method. Another quantum leap in portability was made with this capability. By eliminating the need for a clock drive, I could now indeed use a collapsible camera tripod… if I had an optical instrument that would function on this type of mount.

Figure07 prepoint charts

Figure 7: Bill Gray of Project Pluto has graciously added a feature to Guide 8 star chart software that will create these custom prepoint charts that allow you to arrive at any location at any time and point the telescope at the correct altitude and azimuth of the sky so that the target star will drift through the camera’s field of view at event time.

Galileo makes a return

           Now I arrive at the next quantum leap in asteroidal and lunar observing, returning to Galileo-sized aperture observing systems.

First let’s take a trip back almost two decades… At the Free Electron Laser Center where I once worked, we used 75mm focal length lenses and sensitive Supercircuits CCD cameras by the caseful to image the electron beam path through its high vacuum pipe. One Friday I approached my boss about borrowing some of these lenses and cameras over the weekend to test with my telescope. After these tests with the video camera and lens, I put away my eyepieces and almost never used them again. This simple experiment in the early 1990’s would forge a path that today has lead to a complete 21-station remote observing expedition kit that fits in two suitcases and a backpack ((216) Kleopatra in September 2008)!


When pondering how to shrink my optical system, these decades-old experiments started coming back to me. I had an observation coming up in a few weeks; I was planning on flying to Florida with several stations and deploying them near the Everglades. I dug through my storage boxes and pulled out my old 75mm focal length (42mm aperture) f/1.8 C mount lens and attached it to one of my PC164C Supercircuits cameras and imaged the Pleiades. Figure 8 shows the image taken with stars down to almost 10th magnitude, visible in a very large field of view, perfect for asteroidal occultation observing, and perfect for the 6th magnitude target star for the December 18th, 2007 (219) Thusnelda occultation event in Florida. Even my 25mm C mount lens was capable of imaging a 6th magnitude star. So I sent out an email announcement to the IOTA group stating that C mount camera lenses were a new alternative for portable asteroid occultation timings for targets 9th magnitude or brighter and attached the following picture (Figure 8).


75mm f1_8 C_mount resized


Figure08 PC164_75mm_f1_8_lens_single_frame

Figure 8: On December 6th 2007 I sent this single video field of the Pleiades imaged with my 42mm diameter f/1.8 C mount lens showing stars to almost 10th magnitude. You might say this is the picture “seen around the world.” It began the miniaturization implosion (since observing instruments got smaller it wouldn’t be an explosion?!).

David Dunham and I succeeded in deploying seven remote stations between the two of us. I deployed two with an aperture of 42mm and one with a mere 18mm aperture (a 25mm focal length f/1.4 C mount lens). This event would be the demarcation of a large increase in the number of extra stations per event. After the success of that trip, I devoted nearly all of my energy to finding ways to design optical systems similar in size to these C mount lenses but at a fraction of the cost. I priced 75mm C mount lenses commercially and found they were generally well over $100 each.


            Thinking back again to my early video days, I remembered another routine modification I used to make to my finder scopes. In an effort to not use eyepieces, and especially to not have to stoop over at odd angles looking down the inverted view of my finder scope, I used to attach a camera to my finder scopes and convert each one to a video finder. This removed the crick in my neck from visual finder scopes and also allowed me to use a normal star finder chart — no more standing the chart upside down and backwards to make the view match! I recently purchased an Orion Sky Quest 10” f/4.7 dobsonian that came with a 9x50 finder scope. On one trip to the plumbing section of my local hardware store, I was able to purchase a few dollars worth of PVC parts that allowed me, after unscrewing the permanent focusing mechanism, to couple my PC164C straight to the 9x50 right angle finder. I now had a small video observing scope for a modest price, and it was almost a magnitude more sensitive than the 75mm C mount lens due to the fact the C mount lens aperture was only 42mm, while the 9x50 was a true 50mm aperture.


9X50 PC164CEX2

Figure C. The Orion 9x50 right angle finder converted to a video scope using a PC164CEX-2.

Greedy, aren’t I?

While I built several of these 9x50 video finder scopes, I was still looking for simpler and cheaper. I was going through my stash of optics and lenses, counting to see how many very small systems I could put together to carry to the remote areas of Fort Nelson, British Columbia to get the highest resolution “snapshot” of the asteroid (216) Kleopatra on September 26th, 2008 as possible, to try to resolve if she was indeed a dog bone shape, or the other theory that Kleopatra may be two boulders clumped together ( The ultimate goal for me was to set up, as nearly as possible, 20 chords from the predicted centerline to the 1 sigma error line. David Dunham likewise would squeeze out as many chords south of centerline as he could. As I dug to the bottom of the depths of the lowest elevation of accumulated optics I had collected, I stumbled upon one half of a torn 10x50 binoculars I had purchased around 1995. Back then, I had never gotten any further than tearing up a perfectly good pair of working binoculars. I held this broken piece in my hand and said to it, "I'll give you one hour of my time, and then you’re going in the trash if this doesn't work!" I rooted around for plumbing parts and kluged a few pieces together and held the camera up to the exit end of this optical Frankenstein to see if I could even get a focus. I did right away, and I grabbed a ruler to see how far I would need to build plumbing to attach the camera securely. A few minutes, a hack saw, and a roll of electrical tape later I was holding a prototype ready for testing. As soon as it got dark I took it outside. I didn't even take the time to mount it to a tripod, as I didn't hold out much hope, figuring it would probably suffer from severe spherical aberration among other things, due to its fast f/ratio. But when the first images came into focus I said, "wow!" I immediately scrambled to get a tripod and started doing some closer inspections. What a field of view! And stars everywhere! This was very notably a wider FOV than the Orion 9x50 and with the same about 10.2 limiting magnitude. The field of view was 2.4 by 3.2 degrees.

            Needless to say, what was once a piece of optical scrap just became my most useful remote asteroid occultation observing instrument! In the following days I purchased a brand new pair of binoculars and better plumbing parts, and constructed two very reliable versions of this system. I mailed the other one to Dunham to get his opinion. I got the same wow back from him, and the new name he gave it... The “Mighty Mini”!

20080926 (216) Kleopatra stations OW V1

Figure D. My planned station spacing to map out this computer model prediction of (216) Kleopatra's orientation for September 26th, 2008.
(computer model courtesy of Daniel Hestroffer ( with the Paris Observatory)


As I dug to the bottom of the depths of the lowest elevation of accumulated "optical crap" I had collected, I stumbled upon one half of a torn 10x50 binoculars I had purchased around 1995. Back then, I had never gotten any further than tearing up a perfectly good pair of working binoculars! I held this broken piece in my hand and said to it, "I'll give you one hour of my time, and then you’re going in the trash if this doesn't work!" I rooted around for plumbing parts and kluged a few pieces together and held the camera up to the exit end of this optical Frankenstein to see if I could even get a focus. I did right away, and I grabbed a ruler to see how far I would need to build plumbing to attach the camera securely. A few minutes, a hack saw, and a roll of electrical tape later I was holding a prototype ready for testing. As soon as it got dark I took it outside. I didn't even take the time to mount it to a tripod, as I didn't hold out much hope for it, figuring it would probably suffer from severe spherical aberration among other things due to its fast f/ratio. But when the first images came into focus I said, "WOW!" I immediately scrambled to get a tripod and started doing some closer inspections. What a field of view! And stars  EVERYWHERE! This was very notably a wider FOV than the Orion 9x50 and with the same about 10.2 limiting magnitude. The field of view was 2.4 by 3.2 degrees.


Needless to say, what was once a piece of optical crap just became my most useful remote asteroid occultation observing instrument! (Yes, it passed the 1-hour test). In the following days I purchased a brand new pair of binocs and better plumbing parts, and constructed a pair of a very reliable version of this system. I mailed the other one to Dunham to get his opinion of it. I got the same WOW back from him, and the new name he gave it... The “Mighty Mini”!

How do I make me one of them there Minis?

                The parts that go into a Mighty Mini cost roughly $20 per Mini. First purchase a Tasco 10x50 Essentials binocular (this specific brand works best out of the many brands I tried). The optical objective element is mounted to a tapering barrel and that barrel will literally unscrew from the binocular body that houses the prism mirrors. Both left and right objective lenses will unscrew in this manner, allowing you to make two Minis. From my local hardware store I purchase a PVC plumbing part called a “1 ½” trap adapter”. I also purchase a PVC 1 ¼” diameter x 6” long drain extension tube adapter. Don’t forget to grab a tube of 5 minute quick-dry epoxy.

Lowes trap adapter.jpg                Lowes drain extention.jpg

Mini parts and tools.jpg

saw tube.jpgsawed tube.jpg

tap tube.jpgstrips.jpg


glue front.jpgglue back.jpg

screw in.jpg

            Here’s where you might just get creative with your arts and crafts skills, and you may have to make several iterations to assemble this. You may want to just use electrical tape until you find a combination that works well for you and comes into focus. You may even find a different or better way, but here is what I do:

1.      I hacksaw the smaller diameter pipe off of the 6”drain extension tube. I sandpaper that end of the 1 ¼” housing clean. I throw away the compression nut that comes with this, as it won’t be needed.

2.      Next, I prefer to drill and tap and place a 10-32 thumb screw on this threaded end of that 1 ¼” drain pipe. I realize this may be an advanced type of procedure for some.

3.      Now let’s look at the trap adapter. One end has a larger opening than the other. The smaller end is where you will eventually attach the binocular objective to. The larger end is where the chopped off 1 ¼” drain pipe will insert. But first you need to take some thin strips of (preferably black) paper and shim up the outer diameter of the chopped off 1 ¼” drain pipe so that it slides smoothly in the larger opening of the trap adapter. I usually cut two strips ¾” wide by 11” long and tape this towards the end away from the threaded side (as this is the side that will go in the trap adapter). I usually add one additional layer of just scotch tape after these two strips so that this tube fits very snugly inside the trap adapter (this helps to keep the objective somewhat collimated to the camera’s CCD).

4.      Once this shim is in place I slide the non-threaded end of the 1 ¼” extension tube inside the larger end of the trap adapter and I leave 25mm of the 1 ¼” drain sticking out. This should provide you with the right spacing so that your video camera with an Owl 0.5 focal reducer attached to the correct C mount adapter ( will reach a focus.

5.      Glue the drain pipe to the trap adapter inside and out.

6.      Once the glue dries I spray paint this whole assembly flat black inside and out.

7.      Once the paint dries you are ready to screw the objective into the trap adapter. In almost all cases the trap adapter I buy has a lip on the inside that makes the binocular threads just screw right in tight, no glue needed. About 1 out of 10 that I buy has a loose enough fitting that I feel I need to put a dab of glue around the outside of the threads to keep it together (make sure not to drip glue on the objective!). But in most cases you can simply push the objective forcefully into the trap adapter and you can force the objective to thread right into the trap adapter. If all of this text was not too confusing, you now have a Mighty Mini (refer to Figure 1)!


That feeling of completeness.

            Now I had the perfect portable observing station for events 9th magnitude or brighter, the 8” long (camera included) Mighty Mini! I added one more instrument to my arsenal shortly after this, the Orion 80mm Short Tube Refractor. This is a small observing scope that was designed to be a guide or finder scope and is inexpensive, yet gives me more than another magnitude in sensitivity. So my completely portable observing system would comprise for this:

·         If a star was about 9.5 magnitude or brighter I can deploy dozens of Mighty Minis.

·         If the star is 10.5 magnitude or brighter I can deploy an array of Orion 80mm STs (although I have succeeded in timing occultations to 11.2 magnitude with the 80mm).

·         Anything fainter than that will require my Orion 10” Sky Quest. There are several events a month that can be observed with the Mini and ST.

With the observing equipment in place, I had to develop a routine for deploying them that was simple, repeatable, and—most importantly—successful. After several deployments two different methods evolved. One I would call a “Stamp & Run” procedure, and the other a “Deploy & Run”.


Stamp & Run

  • Prior to end of twilight or start of deployment, as much equipment is assembled and laid out in order of their deployment in my vehicle.
  • Prior to the “Event Time – 122 minutes” RECORD window, sites are pre-pointed to the correct part of sky (but not recording). I deploy them in an order where I finish deployment at Site #1 (closest to centerline, i.e. statistically most important data site).
  • At the “opening” of the RECORD window (longest record time available for my ZR at the moment is 124 minutes in LP mode):
    • Connect one “Y” of video camera to Canon ZR and start RECORD
    • Connect the KIWI Video Input to other “Y” of video camera
    • Press the yellow KIWI RESET button and record Long., Lat., Alt., UT date
    • Record about 10 seconds of UT time
    • WITHOUT STOPPING THE RECORDING I disconnect the KIWI from camera “Y
  • R U N !!!! Make haste to the next site!
  • Continue Stamp & Run as far as you can go until event time passes or you have time stamped all of your pre-pointed sites.
  • If event time hasn’t come and you have extra equipment you can drive further away from centerline and Deploy & Run….

Deploy & Run

  • Deploy & Run starts inside the “Event Time – 122 minutes” RECORD window.
  • In a Deploy & Run your sites may or may not be known
  • You show up at Site #1 (site closest to centerline, i.e. the statistically most significant data site) and pre-point the station to the correct part of the sky.
  • Start RECORD on the Canon ZR camcorder.
  • Time stamp the recording using the Stamp & Run “Y” method.
  • RUN! Drive away from centerline to either your next predetermined site or drive for a predetermined amount of time and find the next suitable site area.
  • Deploy & Run.
  • Continue deploying sites in this manner until event time has passed or equipment is exhausted (or you are exhausted!!!).

Figure09 Deployment minutes histogram


Figure 9 shows the post analysis statistics derived by GPS track records of my deployment times from past events. You can actually see the learning curve! My deployment times have improved so well that at the writing of this article I almost never Stamp & Run, but find I can Deploy & Run within the 2 hour RECORD window nearly the same number of stations as a Stamp & Run.


Ostara 7 pack slide resized


Bottom Line, what good has it done?

In the histogram (Figure 10) of the number of extra stations above 1 per person for all events from 2000 to 2008 we see when the first attempts were being made. On September 7th, 2001 David Dunham got a positive chord from two different stations he deployed. Along with David, sporadic attempts were made after that by many early pioneers of multi-station deployments, notably Roger Venable, Steve Preston, and Dave Gault. Figure 11 shows the benefits of this, a noted increase in the total number of observations being made. Statistics tell us that more observations will lead to more detected events, and psychology tells us that this trend will entice more people to join the “Multiple Chord Club.”Figure10 Extra stations plotV3

Figure 10: Histogram showing the deployment of more than 1 station per person since January 2000.


Figure11 total number obs 2000_2008V2

Figure 11: Total number of observations made over the same period.

Figure12 Metis first Mini Positive Metis profile


Figures 12 shows the results of the (9) Metis occultation where David Dunham made three successful positive measurements using Mighty Minis, the Minis’ first positive event!

December 11th, 2008 would record another major victory for the Mighty Mini and would fully demonstrate the capability of the system. I would get fourteen positive chords through the asteroid (135) Hertha with unprecedented profile details by a single observer. My 14 chords combined with 7 other chords from other observers shows what a team effort with multiple sites can yield. 


Figure13 Hertha profile

Figure 13 shows this Hertha profile, which would later be published in various outlets.

In Conclusion

Figure14 old vs new

Figure 14. Original “portable” station compared to the new and improved Mighty Mini! Galileo would be proud!

Ya’ wanna know more?


OW main screen

                If I’ve piqued your interest in observing asteroid or lunar occultations, there are a number of free resources available to you. Your best bet up front is to join the IOTA discussion group, where you can keep up with the latest in predictions, observing, analysis, equipment, software, etc. The next best thing is to install OccultWatcher (OW) on your computer. OW will take your predefined observing parameters and will daily keep a list of all upcoming events that pass near your area based on these predefined filters. There is an excellent manual written by Richard Nugent called Chasing the Shadow: The IOTA Occultation Observer’s Manual. You just can’t get a better, more complete compilation of information on occultation from A to Z! There are a number of predictions sites with additional information above what OW provides. Occult by Dave Herald will give you the tools to both produce your own lunar and asteroidal predictions, but also reduce the observation. This is a must tool to have! There are a number of free software packages available for reducing your video and converting them into accurate times. LiMovie and Occular are the workhorses of IOTA for this. And don’t forget Guide 8 by Project Pluto for creating those pre-point charts for your deployment!


IOTA Main Page (International Occultation Timing Association)


OccultWatcher (OW is a software package that will track all asteroid and TNO occultations, and satellite mutual events visible from your local observing site)


Occult 4.0 (Lunar and asteroidal occultation prediction and reduction software)


Chasing the Shadow: The IOTA Occultation Observer’s Manual by Richard Nugent

ISBN: 9780615291246


IOTA discussion group (you will want to join this to get involved in continuing ongoing discussions in the field of occultations, the latest equipment, and software updates, etc. It is an extremely valuable knowledge base)



Derek Breit’s Google Maps

Steve Preston’s Maps

Brad Timerson’s NA Ast. Occ. Program Site

KIWI OSD video time inserter


Guide 8 for creating charts:


To see other asteroid profile results:


And the Kudos go to….

                There are many people to thank for compiling the information for this chapter. While I assembled the information, there were a number of contributors to this effort. David Dunham must be thanked for allowing me to pirate some of his Power Point presentations and tips! Dave Herald, Andrea Richichi, and a few others threw interesting comments into this chapter. I mentioned a few others earlier who did early multi station deployment attempts, and there are likely some I missed. Kudos to those for their pioneering spirit! And thank you Paul Maley who on May 6th, 2008 issued me the portable "6 pack" challenge... I went a little overboard with that and forgot to stop at 6!!

                I absolutely must thank Russ Genet for the gentle twist of the arm to get me involved with both presenting my miniature folly at Galileo’s Legacy and for allowing me to write about it here for IYA 2009! Hats off to his wife Cheryl, and to Jo his trusty sidekick for making that conference a smashing success!

                Bill Gray of Project Pluto must get kudos for being willing and FAST about modifying Guide 8 to automate pre-point chart production for unattended non-clock drive stations. He’s a life saver!

                To Colleen Anderson, the ultimate wordsmith who can take any babble I type and make it sound good. THANKS!

                A very special thanks to my good pal Tammy Woods for allowing me at no moment’s notice borrow her Canon ZR10 on numerous occasions. This was one of the pivotal stepping stones for my miniaturization effort.

                And speaking of no moment’s notice, I could not have reached the development I am at today without the support of my wife Michelle! It takes a special kind of support to tolerate the statement, “Honey, I need to leave for Oklahoma in about an hour for an 11 hour drive, and I won’t be back for a few days, and oh, by the way, can you help me carry all this stuff to the van?” with no prior warning, and all due to a few pestering clouds and a shadow I want to snort! I truly could not have done this without her support!

Scotty’s Bio


Scott Degenhardt ( is a native of the Middle Tennessee area and is popularly known for disseminating information about current happenings in the sky. An avid amateur astronomer, he has served as a research member with the International Occultation Timing Association. He helped pioneer the use of video for timing eclipses of stellar and solar system objects. Using this technique, he has discovered three new binary star systems. His recent work to miniaturize remote occultation observing stations has lead to a revolution in the number of sites by a single observer. He currently holds the record of 14 stations for one event.
His background in optics and his technical training and experience in electronics and computers have led Scott along several interesting career paths. He has done everything from controlling broadcasts by satellite for Country Music Television to working on spacecraft for NASA. He spent many years calibrating equipment used to test aircraft, spacecraft, missiles, and rockets at Arnold Air Force Base in Tennessee. He also spent some years on a laser research project at Vanderbilt University’s Free-Electron Laser (FEL) Center. At the FEL Center, Scott worked on the assembly and testing of the prototype monochromatic X-ray machine for MXISystems. He is now assisting in the development of the current model, finding ways to improve and streamline the operation and output of the monochromatic X-ray source.
Scott is certified as a private pilot. He also loves photography, the outdoors, any form of physical fitness, and anything technical. A budding cello player, he enjoys creating musical duets with his wife Michelle, an accomplished pianist. Scott published a book in 2005 called Surviving Death, a detailed accounting of what he learned from 14 years of research into the Near-Death Experience.