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.
Effects of Optical Miniaturization on Occultations
By Scott Degenhardt (scotty@scottysmightymini.com)
Contents
Heavenly
bodies passing in the night
Hold
still while I take your measurement!.
Can
you point me in the right direction?.
How
do I make me one of them there Minis?.
Bottom Line, what good has it
done?
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
(http://www.poyntsource.com/IOTAmanual/index.htm).
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
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
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.
Figure 3: Lunar
profile from the graze of delta Cancri on May 9/10, 1981. (courtesy David
Dunham)
Stars gone wild?
On
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
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
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.
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
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.
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.
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.
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
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.
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 (http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/full/2002/40/aa2501/aa2501.right.html).
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”!
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 (daniel.hestroffer@obspm.fr) 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.
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 (http://www.owlastronomy.com/barlows.htm)
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!!!).
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.
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 
Figure 10: Histogram showing the deployment
of more than 1 station per person since January 2000.
Figure 11: Total number of observations made over the same period.
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.
Figure 13 shows this Hertha
profile, which would later be published in various outlets.
In Conclusion
Figure 14. Original “portable” station compared to the new and improved Mighty Mini! Galileo would be proud!
Ya’ wanna know more?
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!
References:
IOTA Main Page (International Occultation Timing Association)
http://www.lunar-occultations.com/iota/iotandx.htm
OccultWatcher (OW is a software package that will track all asteroid and TNO occultations, and satellite mutual events visible from your local observing site)
http://www.hristopavlov.net/OccultWatcher/OccultWatcher.html
Occult 4.0 (Lunar and asteroidal occultation prediction and reduction software)
http://www.lunar-occultations.com/iota/occult4.htm
Chasing the Shadow: The IOTA Occultation Observer’s Manual by Richard Nugent
ISBN: 9780615291246 http://www.poyntsource.com/IOTAmanual/Preview.htm
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)
IOTAoccultations@yahoogroups.com
Predictions:
Derek Breit’s Google Maps
http://www.poyntsource.com/New/Global.htm
Steve Preston’s Maps
http://www.asteroidoccultation.com/IndexAll.htm
Brad Timerson’s NA Ast. Occ.
Program Site
http://www.asteroidoccultation.com/observations/NA/
KIWI OSD video time inserter
http://www.pfdsystems.com/kiwiosd.html
Guide 8 for creating charts:
To see other asteroid profile
results:
http://www.asteroidoccultation.com/observations/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 (scottyd@charter.net)
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.