Simple to operate equipment available for those within 100 miles of the central line
Since observations with a cadence of 0.1s or faster are desired for the central flash observations, with a timing precision
of 0.1s or better needed, observation with sensitive video cameras with accurate timing are preferred over most standard
astronomical CCD imaging systems. If your observatory has a 14-in. or larger telescope with robust pointing and tracking, is
within 100 miles of the central line, and you don’t already have an accurately-timed recording system, such as ADVS, QHY
174M GPS, or video with IOTA-VTI, Kiwi OSD, Blackbox Camera Sprite or other 1PPS GPS video time inserter, I can
send/loan you a simple-to-use video system, including an IOTA-VTI, to make the observation with your telescope. The
front end will be a 1.25” focal reducer attached to the small but sensitive Supercircuits PC164C-EX2 camera that will fit into
any standard 1.25” eyepiece holder; the to-focus distance is similar to that for many eyepieces. The back end is a USB
cable that attaches to a laptop PC; you need to download the free IOTA_VideoCapture software (for that, see the
PC164C-EX2 camera with 1.25” focal reducer on front end and female RCA for the video out
2 male-to-male RCA cables, 1 from the camera to the
IOTA-VTI time inserter (plug into the “in” RCA female plug)
StarTech SVID2USB23 analog video capture device - connected to the IOTA-VTI “out” RCA female plug with the 2nd RCA male-to-
[The StarTech device has 3 RCA female inputs; the yellow one is for video, while the other two (red and white) are for audio; we
normally don’t use the latter]
Two 8-cell AA battery holders that will provide 12v power to the camera and IOTA-VTI for several hours
Note that in the Aug. 10th version, I mistakenly called most of the connectors “BNC”; they are actually “RCA”, as specified above.
The video out of the PC164C-EX2 is a male BNC, but I’ve placed a female BNC-to-female RCA connector there, so all you need to
worry about are the standard RCA connections.
Slide 2 of VideoPackageSlides.pdf shows everything connected and working. Letters identify the components and major
connections with a key describing each below; this tells you basically how to connect and operate the equipment:
A. Mighty Mini, just half a pair of Walmart binoculars sawed off, glued to a 1.25” inner diameter PVC pipe fitting, painted
black, all just to provide a simple optic, to focus the view across the room. Of course, instead it will be your telescope with
the 1.25” eyepiece holder.
B. Supercircuits PC164C-EX2 camera with 1.25” focal reducer on front end. The focal reducer is not visible in this view
since it’s inside the back end of the Mighty Mini. Incidentally, this system can image stars to about mag. 9.5 with a
3 x 2 deg. FOV, so it makes a good video finder.
C. Cell holding 8 AA batteries connected to the camera to provide 12V DC power for it. Only the cell with the
connector is provided; you need to supply the AA batteries. Note that they go in the cell in alternating order +-,
then -+, then +-, etc. You should always place the negative end of the battery where the spring is in the cell.
D. Male-to-male RCA cable connecting the camera to the IOTA-VTI.
E. The IOTA-VTI GPS video time inserter. The GPS receiver is in the box so the box should have some view of the sky.
The slit in an observatory dome will probably be enough to keep it going, but to initially achieve lock, you may
need to take the unit outside (with its 12V power supply attached). It’s a simple-to-operate unit; some details
F. Cable D is connected to the “IN” jack on the back of the IOTA-VTI.
G. This is a switch on the front of the IOTA-VTI. It is normally kept in the “down” “Time” position, to provide the
accurate 1PPS time display stamped on every video frame, but a short video recording should also be made with it
in the “up” “Position” position that gives accurate GPS coordinates (WGS 84 datum and height referred to sea
level), approximate time (just to the nearest second, changing each 3 seconds) and status of the GPS reception.
H. This is a yellow light that flashes once per second only when GPS lock is achieved; it is driven by the accurate 1PPS
signal, accurate to less than a millisecond. You should watch this when you first apply power to the unit, and the
unit shouldn’t be used for timing before this yellow light starts blinking.
I. This is the power indicator, a red LED; if it’s dark, check the power connection and battery pack.
J. The cell holding 8 AA batteries, like C above, to power the IOTA-VTI. The back view in Slide 4 shows the connection.
K. The video “OUT” jack on the back of the IOTA-VTI, not visible in this view, next to the “IN” jack F.
L. Like D, a male-to-male RCA cable connecting the IOTA-VTI to the StarTech video frame grabber.
M. The connection of cable L (red end) to the video in (RCA female, yellow) jack of the StarTech.
N. The StarTech SVID2USB23 analog video capture device. The “N” is the only red letter, to contrast with the black of the
O. The USB connector from the StarTech to your PC. The StarTech device needs a driver that you can download from
you attach the SVID2USB23.
P. This is the display of the video on the PC (laptop in this case) using IOTA_VideoCapture, which you can download and
focus on something prominent and recognizable, like Jupiter or Saturn; you should see some of their moons. Once
focused, you can start finding things with your telescope just like you would when observing visually with an eyepiece. If
you have and know how to use SharpCap, it can be used in place of IOTA_VideoCapture.
Q. At the bottom of the video display is the superimposed IOTA-VTI time display; if it’s not there, check your connections and
the status of the IOTA-VTI. The left-most item is F# or P#, where # is the number of GPS satellites currently locked on. It
must be 4 or greater in order for accurate time to display. The next numbers (from left to right) are UTC hours, minutes,
and seconds. The next 4-digit numbers are the fractions of the second, in units of 0.1 millisecond, for the start and end of
the video frame. Following it is a larger number that is a count of the video fields from when the IOTA-VTI was turned on.
More about this is in the videotimers Web site with URL given in item E above.
R. These two small boxes control your recording to the PC. Click on the red circle on the left to start a recording. Then the
gray square to its right turns black, and click on it to end the recording. Make sure that your PC has enough free memory
to record the occultation; about 1 gigabyte per minute of recording is needed.
Slide 3 of the Power Point file is like Slide 2, except that the mighty mini has been removed. Now you can see the front end of the
camera (B) with the 1.25” 0.5 focal reducer that will go into the eyepiece holder of your telescope. Since in this view, no optics are
connected to the camera, the video view P on the laptop is blank, except for the IOTA-VTI time display at the bottom.
Slide 4 is like slide 3, but a view from the back. It shows the connections F and K at the back of the IOTA-VTI, and also the place S
where the battery pack J connects to power the IOTA-VTI.
Slide 5 is like Slide 3, but showing the equipment of System 1 rather than System 2. The only difference is the color of the ends of
the RCA cable D, white instead of red. Some of the RCA cables have yellow ends.
When observing, you will notice that the PC164C-EX2 camera has a lot of hot pixels that mimic well-focused stars. Just move the
view a little, to distinguish the real stars from the hot pixels, and try to ignore the latter. When tracking and recording for the
occultation, make sure that the target star is not on or very close to a hot pixel; you may need to make some minor adjustments
during the observation to ensure this. Try to avoid such adjustments within +/-3 minutes of the predicted time for your location.
We usually use the equipment with small telescopes. For use with larger telescopes like we want to use for the Pluto occultation,
the cables will probably be too short for ease of use at the telescope. Especially, the battery pack C needs to be close to the
camera in the eyepiece holder; I recommend just taping it to a nearby part of the telescope where it won’t interfere with the
telescope’s operation. Duct tape can be used to do that, but I recommend instead using blue painter’s tape, since it leaves less of a
sticky mess when removed after observing. The two RCA cables, D and L, can be interchanged; use the longest one for D, so that
the IOTA-VTI and all the other connections, including the laptop or other PC, can be as far from the end of the telescope as
possible. You may have, or be able to purchase locally, longer RCA cables from old stereo or other electronic equipment that you
have, that could be used in place of D; test to see what works for you. We normally put the IOTA-VTI to laptop (everything from E
to R, and S) on a small folding table that we can easily move around as the telescope slews. For large slews, you might disconnect
D so that only the camera and its power source moves, then reconnect once you need to observe again.
Other cameras, such as the Watec 910HX, 910BD, or the older 120N, or the new RunCam Night Eagle Astro IOTA edition, are
better in that they have about the same sensitivity as the PC164C-EX2’s, but they have fewer (usually none) hot pixels and their
FOV is larger since they have half-inch chips, rather than the third-inch chip of the CCD of the PC164C-EX2. If you have access to
one of these other cameras and know how to use it, you should. But the advantage of the PC164C-EX2 is that it is simple, without
the onscreen displays of the other cameras mentioned, that have a number of settings that need to be optimized, i.e., a higher
learning curve. These other cameras have field/frame integration, to increase S/N and see fainter stars, but try to keep the time
resolution to 0.1 second or lower, or 8 fields or less integration. Non-integrated recordings like those made with the PC164C-EX2
can be “integrated” after the fact with software such as Registax.
Good luck with your observations. If you have any further questions about using the equipment, or if any problems develop, feel
free to email, text, or call me.
David Dunham, firstname.lastname@example.org, phone 301-526-5590, 2018 August 12, version 1
Joan Dunham, email@example.com, phone 301-526-5591