Ed, Steve, and I traveled to our radio telescope site, leaving from the Ellicott Fire Department a little after 7:30 am. We encountered just a little fog on the way.
Steve worked primarily on troubleshooting the amplifier failure on the 60-foot antenna fiber optic feed. Steve found a power supply no longer functioned. He wrote me later, “Damaged parts have been ordered and will be replaced at the earliest convenience.”
Ed Corn and I worked on assembling the 3-element tri-band Yagi antenna from Myron Babcock, and then the ham radio tower by the bunker, on which the Yagi antenna will go. We measured and reassembled the three Yagi antenna elements and the boom support for them. We’ll wait to combine those until we are ready to attach the antenna to a mast and on to the tower. The antenna will operate on the ham 10, 15, and 20 meter bands. We decided to set the lengths so that the antenna tunes best in the center portions of the bands.
We assembled the tower components out to a length of 50 feet, including the top that will hold the rotor. The tower is now designed and built to rotate from a pivot point next to the existing tower that had been started earlier. Ed climbed that original tower to install the pulley; the pulley leverages and pulls up the 50-foot tower by rotation at the pivot. We tested lifting the 50 foot tower with the hand crank winch that I think came from Steve. The design works. We eventually will need to take down the mast that supports the 80 and 160 meter dipole antennas, to complete the tower build-out. We plan to re-attaching those antennas to the tower itself, when we are ready to complete the tower. Ed has already fabricated two standoffs that will attach to the sides of the tower, and centrally support the dipole antennas.
Ed from time to time went to help Steve. And Steve once in a while came to help with the tower assembly.
We had a lunch break together in the bunker. I brought a small coffee maker and brewed coffee for Ed and me.
The weather was good, considering the heat we’ve been having lately. High cirrostratus and mid level clouds from storms in the distance covered us for the afternoon, and kept the heat and sunshine comfortable. We saw rain showers in the far distance, but those never came close enough to bother us. The bunker thermometer read 75 F, and outdoors was probably just a little warmer.
During a break I got on the air at the bunker station, and made 12 contacts for QSO parties that were running: 1 to Hawaii, 5 to Ohio, and 6 to Kansas, on CW and SSB, on 20 and 40 meters. I submitted our logs to those QSO parties later.
Here is a quick site
trip report on the work the System 1 team (Phil Gage, Lewis Putnam, Dave Molter
and Glenn Davis) completed at the Haswell Site yesterday (8/17/2019):
We installed Version 4.0 of the System 1 software. This version includes a major new capability that supports manual tracking of astronomical objects. I would like to demonstrate this capability at the next Science or Engineering meeting.
Version 4 included a software update to fix the Elevation Axis Bounce Issue (Erroneous Elevation Axis Status) that was identified earlier this summer and has been investigated for several years. The problem was related to the Elevation Axis Integrity Instruments 232M200 I/O module. Due to a board related hardware problem, the I/O board was always reporting bit 2 of the encoder position data as “stuck” on (1) which would create erroneous Elevation encoder data. The fix required both a hardware and software modification. The hardware modification included moving the bit 2 pin to an unused position on the connector to the I/O module (see #3) then provide a software fix that would read data from this new bit position and re-incorporate the bit data back into the Elevation encoder position data – bypassing the bad bit. This hardware/software solution has fixed the problem. The Elevation Axis is now providing the correct encoder positions through it’s range of motion and the “bouncing” has been eliminated.
Dave Molter moved and soldered the “bad” Elevation Axis hardware pin to support the software modification that fixes the Elevation Axis Bounce issue.
Collected Voltage to Rate information for both axis – data below:
Please note: We were unable to produce zero rates on the
elevation axis – even with the potentiometer turn all the way down.
Additionally, though we believe we returned the potentiometers back to their normal positions, whoever returns to the site for the next data collection, please ensure the potentiometers are at their normal positions before use.
My wife and I spent the day at the site cleaning up the last of the electric basic infrastructure build out. That portion is complete with the following items completed.
Basic plug ins complete including a GFI plug near the sink and one in the bathroom for portable heater.
A pre wire and extra switch in bathroom for future ex-host fan and an electric water heater for shower and kitchen sink.
Box and wiring for sewer pump when that project starts.
Wall switch and permanent light in sleeping area.
The tunnel lights now have a control switch at both ends.
240 volt plugins for amplifiers at the Amateur operating position.
The sub main electric panel in the battery room is complete and the main panel has the trim cover installed.
There will be extra plugs and services that will be needed in the future but basic build out is complete.
Scheduled Maintenance Trip Report for July 20
Steve and I went down
Friday the 19th. We met Paul Berge at the house in Haswell. Paul and his wife
came down Thursday and stayed over Thursday and Friday nights. Steve and I
stayed in the bunker Friday night.
Paul worked on finishing installing the control wiring in the pedestal in the conduit for mechanical protection, and he installed heavy duty override switches in the override panel in the comm trailer. He also gathered information for some updates on the control wiring. He will be working on the updates at his home computer.
Steve worked on the
fiber link from the feed point to the comm trailer. The wind came up Saturday
so Steve will complete work later as the wind was a safety issue trying to work
up at the feed point. Steve did say the az/el readout worked after cycling
I have the two 30 amp plug-in circuits at the old generator building completed to give us 2 more RV parking spots with heavy enough power to run 1 air conditioner in each RV. Just for information to turn lights on in the generator building you will have to turn the circuit breakers on in the distribution panel in the middle of the North wall.
DSES Plishner Site Trip Report 6-14-2019 By: Bill Miller, Bob Haggart. Photos by Bob Haggart.
Location: Plishner Radio and Space Science Center, Haswell, Co. Attendance: Steve Plock, Rich Russel, Jonathon Ayers, Floyd Glick, Bob Haggart, Bill Miller
Accuracy: This is only a summary of my work on Friday and Bob Haggart trip from his report for Saturday and you should add your own and correct anything I missed. WKM.
Bill Miller’s Work Trip Report, Friday, June 14th Bill was the first to arrive at the site about 10:15 on Friday 6/14 and started by opening the trailer and removing the exhaust fan cover. He lubricated and reattaching the fan wires, started the air conditioners, swept the Comm. trailer floor and removed the mud left from the last visit. Steve came in shortly after and he and Bill went to the top of the tower to inspect the Liquid-tight conduit that Steve had previously installed for the elevation position synchro wiring.
Jonathon Ayers came in and assisted Bill to hook up the wiring to the synchros on the elevation axis in the top deck.
Bill then got some assistance from Floyd Glick while hooking up the wiring in the control deck of the dish pedestal. Thank you to Jonathon and Floyd. The goal was to attach the Elevation position synchro encoders to the synchro panel in the Comm. trailer. This would match to connections of the Azimuth synchros previously installed. It would complete the synchro dish position indicator system which is an accurate minimal tech backup dish positioning system that needs no computer.
Bill was under a tight schedule as Rich had a pulsar observation planned to start at 3:30. Bill tested the system and it worked initially but then started tripping the ground fault interrupter on the synchro panel within a few minutes indicating that the insulation or electrical clearance of the elevation connections was breaking down somewhere in the path. Because this circuit is 120VAC, the ground fault interrupter is critical to safe the system with the many intermediate connections and it did its job. (Caution) Bill unplugged the synchro panel from AC and it should be left unplugged until we have a chance to trace down the fault in the elevation wiring. It is most likely in the old terminal box in the control deck, moisture in the system or hasty wiring in the elevation axis Encoder box. I also believe that the synchros in the elevation axis box are either bad or incompatible and should be changed out and matched to those in the trailer synchro panel. Ed Johnson has a box of synchros from the bunker.
Bill had to leave about 4:00PM while Rich, Floyd and Steve stayed to make their Pulsar observation. This seemed to be going well but the large storm was brewing in the area and I suspect they had to abandon the site that evening.
From Bob Haggard’s Work Trip Report. Saturday, June 15th Arrived at the DSES site 8:35am. Opened gate, opened the bunker to retrieve keys. Noticed the dish was setting at about 45 degrees. Opened the Ops trailer and the battery box for 110V AC power. Mounted the solar powered, dusk to dawn, LED porch light. Removed the camera and the broken rear trailer window. Installed the clear window and camera right side up. (there you go Rich) The molding to hold the window in was rotten, have to make 4 new ones. The putty was too old to be used, will need more on next trip.
Removed two folding chairs from battery box and stored them in the OPs trailer under the table next to the filing cabinet. Stored the donated table saw and stand in the battery box. Picked up all unused unwanted lumber (there you go Steve)
Secured the battery box and the Ops trailer. Returned the keys to the desk and secured the bunker and gate. Secured the main gate and departed at 2:45.
No one else showed up for this work day.
The weather was perfect, a mild breeze, just enough to keep you cool while working in the hot sun.
(Editor’s Note: This is Ed Corn’s report of our work at the Plishner radio telescope site during the weekend of May 18, 2019 – Gary, WA2JQZ)
I arrived about 9:30 AM and proceeded to the generator shed to install breakers and to survey the conduit route for 2 extra camper hook ups. The breaker box is ready. I will run conduit and wiring during another trip prior to the open house.
Steve Plock arrived shortly there after. We traveled separately so Steve could stay over with Paul Berge, as I have a graduation to attend on Sunday. We looked at the ham radio tower project. All the hardware is on site but tower climbing is out for most of us. Steve decided we will assemble the tower on the ground, and tip it up with a winch at a later trip. We need a few extra parts to do this which are easily obtained or fabricated. Gary Agranat arrived and went to work on the vertical antenna. The vertical was damaged during the blizzard storm several weeks ago. He has a list of all needed parts for fixing on the next trip.
Steve moved the dish to the work stand and checked the control voltage for the feed to the preamps, and adjusted for voltage drop in the line from the communications trailer.
Steve and Gary then worked on tuning the 16o meter and 80 meter wire antennas. (Gary added: We trimmed the lengths to retune the antennas to about the center of the ham bands. The 160 meter antenna was tuned to 1.9 MHz, with a best SWR of 1.7:1. The 80 meter antenna was tuned with an SWR of 1:1 from 3.8 to 3.9 MHz. Before the tuning, each antenna was slightly long, which therefore gave better performance at the low ends of the bands. The retuning enabled better resonance in the phone portion of the bands, where several members like to participate in nets.)
I moved into the bunker and pulled wire for the sub main panel in the battery room, in preparation for the hot water heater for the sink and shower and the sewer pump system. The sub main is complete, ready for extension of the conduit runs on a future trip.
Paul arrived late afternoon and stayed the weekend with several items he wanted to work on.
Bob Haggart N0CTV is working on building a new stairway and porch to the communications trailer at the radio telescope site. He started the work at home after taking measurements. Today he traveled to the site to continue the work. With him were his grandson Allen and Allen’s friend Ben. Bob writes:
“We arrived at 11 AM. Worked on the porch and covered the fan with 24″ X 24″ plywood. Ran out of time but did get the porch assembled and painted inside and out. The hand railing is only temporary and will finish next work day on the 17th.”
Bob’s work is replacing a small simple set of metal steps that has given us access to the communications trailer.
The new porch and stairway provide a great improvement.
Thanks to Bob for all this work, and for improving the access to the communications trailer.
Attendance: Gary Agranat, Ed Corn, Floyd Glick, Glenn Davis, Steve Plock, Rich Russel, Tony Bigbee, Ray Uberecken, Dave Molter, Jon Richardson, Bill Miller
Attending Remotely via TeamViewer: Skip Crilly, Dayton Jones, Jamie Riggs
Last Trips: Oct 19 Observation Trip. Oct 20 Work trip for ED. Steve, Hans, Gary, Paul
Next Trips to site: The regularly scheduled 3rd Saturday of the month, Saturday Nov 17th. Observation the night before on Nov 16th
DSES Technical and Operations Meeting- 2nd Monday of Every Month
DSES Science Meeting – 4th Monday of Every Month
Accuracy: The notes for this meeting may be out of order. This was done to group the discussion into subjects for better clarity and continuity, so they are not true chronological minutes. As always if I have misstated, omitted or misrepresented anyone please feel free to correct me WKM.
Agenda and Notes
Ray Uberecken has his mount ready to install a 12 ft dish with capability up thru the KU band. He needs to move the dish from the KCME radio station to his site in Payton. The dish F/D ratio is the same as the 60 ft Haswell dish, so the 12 ft dish could be used to prototype feeds and receivers for the Plishner site. Ray would like some volunteers from the DSES to help move it next Sunday the 28th at 10AM. (Note: Recent change of plans. Ray will hire a crane to pick the dish out of the KCME yard enclosure before disassembly. This is currently scheduled for 7 AM Saturday, November 10th.) He could use some volunteers, power drills with sockets and a trailer. KCME is at Fontanero and 1921 N. Weber in. Bill will send an EMAIL out to the group.
Once the dish is in place the first thing that Ray will install is a Dicke Switch.
Ray also wants to know if we want to use the 8 channel UHF remote at the site for reset and control of the systems. We have not been using it, but that is available and installed in the communications trailer rack and can be commanded remotely from Ray’s residence.
Ray has also started his optical observatory with 8 inch Celestron and a good refractor at his residence.
Dr. Rich Russel reviewed his new Radio Astronomy Guide Rev. 3.
The RA/Dec of many of the objects are from both celestial coordinate year 1950 epoch and year 2000 epoch, so needs updating.
The output of the SpectraCyber is in volts and a translation to Jansky is needed.
Rich and Gary observed a number of sources on the Oct. 19th observation trip.
Some source positions were very good. Others were not. This may indicate a pointing error or other system issue.
They were getting a lot of clear source signatures but don’t know what many of them were. Rich would like to do cross galactic scans while changing declination to map the whole area in the future.
Cassiopeia A, Cas-A, was thought to be seen, but at a relatively low amplitude. Cas-A, being a 2200 Jy source it should have been clearly seen but they weren’t sure they had it.
Sagittarius A was strong and had the instrument setup with too high of gain, resulting in scale saturation.
Special sources 1 and 2 were studied.
The special source 2, a contact binary star is getting close to a supernova event in a few years, and we want to baseline it and get ready to observe the supernova emission.
To find objects Gary used the tables in Rich’s observing guide and in the Data Book “Astrophysical Data: Planets and Stars” by Kenneth R. Lang.
The V notch object that Tony studied was not tried in Rich and Gary’s session.
Rich and Gary also did an experiment to measure the hydrogen (HI) Line Doppler shift and therefor the velocity along the galactic plane. They were able to get reasonable hydrogen measurements of the galaxy’s rotational velocity at multiple points from the center out to the radius of the sun.
Rich plotted these observations and got a curve that is in the ballpark but a little different than the published data on similar measurements. This is the first time that the Galactic angular velocity measurement has been attempted with the 60 ft. dish.
See Dr. Rich Russel’s attached Science Meeting presentation for more detail on the site trip and the observations mentioned above.
Tony Bigbee also went to the site for the observing session last week. Tony installed onto the system after Rich and Gary had finished. He did not get the expected results on the RASDR 4 receiver when attached to the 60 ft. dish over the weekend. He thought that the issue may be with the pointing accuracy of the System 1 controller. We used System 2 at the open house when Tony had very good results but did not get the same on this last weekend’s observation session using System 1. Tony looked for the V notch absorption object and is using a new code to calculate the source amplitude. He did not get good results on this and suspects pointing error.
He calculated the curves for the open house and last weekend’s observations showing time and discovered that these are different indicating that something is wrong between the two.
Tony did a Mollweide projection plot like the one below. In Tony’s plot the green line is the meridian, the blue line is the galactic plane. The black X is the position of the telescope. See Tony Bigbee’s actual plot when he posts or sends it out.
Rich suggests that anyone going down to observe should measure some of these same sources and get data to compare their results.
SkipCrilly says we have aligned NRAO 5690 at Greenbank and Haswell sites three times using the System 1 controller and it seems to be positioning correctly. Steve can do an additional observation next week, Tuesday and Wed and verify the alignment.
Another difference from the open house observation was that Steve Plock added the alternate cavity filter configuration.
As mentioned previously the coordinates of some of the sources are from celestial coordinate year 1950 epoch and year 2000 epoch so may be different positions now due to precession and galactic movement. A mathematical correction to the coordinates may be required to make an accurate set of coordinates for the current date. However, the small difference afforded by this is probably within the capture angle of the dish.
Glenn Davis says that his NTP time sever may be useful to improve the accuracy of the pointing systems.
Bill Miller said that the System 1 controller may still have a discontinuous elevation reading error. This was seen previously this summer and has not been fixed. This could contribute to a pointing error and inaccuracy on some coordinates.
Anyone going to do observations at the site should try to replicate the studies of the observation guide and use the Observation Checklist to make their session useful and comparative.
Currently the LMST is close to local time, and so one needs to consider this and observe in the evening instead of afternoon.
See the back of Rich Russel’s observing guide for dish rules and limits. An observation data sheet and suggestions are available in the back of the guide as well.
We need a list of some calibration sources to start all observing session with, to be sure that the pointing system is working properly and that it isn’t broken with new SW drops. Also, we hope the voltages we measure from calibration sources (with known Jansky levels), will enable us to derive the Janskies of other objects we wish to observe. Janskies are the measure of the flux density that the antenna receives.
Three papers have been accepted in the next SARA journal.
“The Deep Space Exploration Society 2018 Perseid Meteor Shower Open House”. By Bill Miller, Gary Agranat. Deep Space Exploration Society.
“SpectraCyber Neutral Hydrogen Measurements using the Deep Space Exploration Society 60 – foot Antenna System“. By Richard Russel D.Cs., Ae.E.; Gary Agranat. Deep Space Exploration Society.
“Dark HI Cloud Observation using the Deep Space Exploration Society Plishner 18 – Meter Dish with the RASDR4“. By Tony Bigbee, Richard Russel, Steve Plock. Deep Space Exploration Society.
Skip Crilly discussed his new 28 ft. antenna that has a 5 pixel or 5 separate antenna segment feed and is mounted on a cargo trailer but will be used mostly for SETI. The antenna may not be large enough to observe the strange signals we have seen. File size is one challenge since it is inversely proportional to the gain and noise ratio.
Meeting was adjourned after much secondary discussions not captured here.
Old 9/24/2018 Agenda and Notes from last science meeting:
Glenn Davis proposes a graphical user interface called Astro Guide that would allow better guiding and tracking of radio sources.
Rich’s presentation and overview of the radio astronomy guide
Started with Floyd’s list
Added the 1420 MHz sources from the book “Tools of Radio Astronomy” by K Rohlfs and T Wilson.
Added the hydrogen measurements from K5SO, Dr. Joe Martin who has provided signature images of the objects.
Gary, Jay Wilson, Rich and Steve all went to the site on 9/22 and did observations using the 60 foot dish.
Used Spectra Cyber
Used system 1 pointing
Used the new setup with the cavity filter
Limit switches are set at +/-15 ether way of north. CCW to 345. CW to 015.
Gary got great pictures of the event.
Need screen print capability to capture the Spectra Cyber parameters display.
The Spectra Cyber SW is easy to take the data and use it.
Need a Lap Top with a com 2 serial port to attach the spectra cyber. This is difficult because most of the Serial to USB port adapters don’t want to set for Com1 or Com2.
Need to do calibration sources before and after observation of an observed object and keep all settings on the Spectra Cyber the same.
From Tony, “To avoid problems of solar interference all observations were made between sunset and sunrise. Most scans were taken with the telescope on the meridian.” Galt and Kennedy, 1968, ‘Survey of Radio Sources Observed in the Continuum near 1420 MHz, Declinations —5° to +70°’ http://adsabs.harvard.edu/abs/1968AJ…..73..135G
Rich presented a number of plots from their observations. See Rich’s report.
The scan across the galaxy were at one RA. The radio hot area was offset from the optical.
The galactic rotation rate was also observed.
Got a lot of raw data, learned how to catalog it and analyze it.
The calibration sources did not show any signal above the noise.
Got good data for Sagittarius A, SAG A.
3 Papers have been submitted for the SARA Journal.
The Western SARA conference is in Boulder in March.
This is a summary of our activities at the Plishner radio telescope site during the third week of October 2018. Steve Plock, Ed Corn, and Gary Agranat contributed to this report.
Participants this weekend were Gary Agranat, Paul Berge, Tony Bigbee, Ed Corn, Hans Gaensbauer, Dave Molter, Steve Plock, and Rich Russel.
Our plan for the rest of the year is to work at the site during the third weekend of each month. The Friday evening is devoted to astronomical observing, and the rest of the weekend is then devoted primarily to infrastructure and equipment work.
60-foot Antenna Observing, by Gary Agranat, WA2JQZ
On Friday afternoon and evening Rich, Gary, and Paul did 1420 MHz neutral hydrogen observing with the 60-foot antenna. The primary observing goal was to take regular measurements of the hydrogen signal along the Milky Way galactic plane at 10 degree intervals, from the galactic center to about 110 degrees (a little more than the first quadrant). The Doppler shift of the hydrogen was measured at each 10 degree point. From that, Rich later used some basic geometry to derive a velocity and distance from the galactic center for each measurement. A second goal was to observe several known, strong galactic radio sources that could be used in the future for calibration of our observations, and also to see if we are capable of observing those sources in a consistent way (without unknown biases). A third goal was to observe additional galactic sources as targets of opportunity, to see how well we do, and to also see what problems we hit.
Galactic plane observing started at about 5 pm local time, when the galactic center in Sagitarius had risen high enough in the sky for us to observe. The galactic plane and most of the other observing were done with the 60 foot antenna pointed along the meridian (180 degrees azimuth to the south and zero degrees to the north), in order to eliminate the Earth’s rotational motion in the Doppler shift measurements. We observed until about 10:30 pm, when the team was then quite tired. To warm us up during the evening, we made a batch of hot apple cider.
Details of the observations and results were discussed at the science meeting on Monday October 22nd, and those will be covered in a separate post.
– Gary WA2JQZ
We’ll continue with the discussion of the weekend infrastructure work.
Saturday Infrastructure Work by Ed Corn, KC0TBE
Our first order of business was to re-service the toilet and spare in the outhouse. They now both have RV antifreeze for winter. Next installed was a portable heater for winter operations and I labeled all the breakers in the out house. I then labeled the doors with instructions for emergency exit and the safety pin for privacy at the main door.
With the help of Gary, Hans, and Paul we have the first 3 tower sections in place at the bunker, along with the first set of guy wires. [More about the tower below.]
-73’s Ed KC0TBE
DSES Site Work Report by Steve Plock KL7IZW, DSES President
Paul Berge worked on Friday, Saturday and Sunday. Because he travels from Lyons, Co. he prefers to maximize his efforts each visit. Also the weather window for the year is closing. I attempt to support his efforts as best as I can. Paul provided support for Rich Russel’s data acquisition which included galactic Doppler measurements. The team knocked off before midnight. Results have already been detailed in the Science meeting on 22nd of October.
On Saturday Ed installed a heater in the outhouse, winterized the RV toilets, and labeled the outhouse breakers.
During Saturday afternoon Hans, Ed, Paul, Steve and Gary all worked together to erect the new communications tower. The first set of guys were finished at 23 ft. by Ed Corn doing all the climbing. The majority of the rest of Saturday myself and Paul spent evaluating the elevation limit switch operation, including testing complete functionality with fault clearing via the built in override capability.
Later that day, Tony Bigbee showed up, and Paul and Steve supported subsequent hydrogen observations using the RASDR4 receiver.
The majority of Sunday was consumed by lubrication of the dish and adjustment of the azimuth drive chain. I also installed the conduit in the elevation bulkhead so that Bill Miller can complete his synchro wiring project.
Sunday Dave Molter worked into the night using the 500W floodlights and mixed over 1000lbs of concrete to try to prevent continued erosion in the ramp area. A big thanks to all who participated in this cooperative effort.
Participants: Steve Plock, Ed Corn, Rich Russel, Dave Molter, Gary Agranat.
Summary and photos by Gary Agranat.
We worked at the Plishner Radio Telescope site on Saturday August 25, 2018. One motivation was to proceed with needed infrastructure work before the cold of winter returns. Another motivation was to follow up on the observations we made during the Open House with the 60-foot antenna. In addition, the antenna tuner for the bunker ham radio station was still not running, and needed to be checked. Here is a summary of what we did, with some photos.
1. Ed and Steve replaced the outflow hose from the ramp sump with one more durable (including durable against mice). Ed tested that the outflow did drain away from the ramp area. We placed a new aluminum manhole cover on the sump access (vs the original steel one), fabricated by Steve.
2. Ed moved the Internet hotspot to the bunker. The hotspot was used by Gary while testing and operating the ham radio station.
3. Dave brought 20 x 60-pound bags of cement, and used all of them to continue to repair/rebuild the ramp retaining wall. He made considerable progress extending the base of the wall. The higher the base of the wall reaches up the ramp, the less rain sediment will clog the sump pump. Dave stayed until late in the evening, until around sunset. Gary stayed with him and gave some help.
4. Rich brought the SpectraCyber 1420 MHz Hydrogen Line Spectrometer, and used it to continue to test the functioning and ability of the SpectraCyber together with the System 1 pointing system on the 60-foot antenna. Rich later showed Gary how to steer the dish antenna, and how to measure and record neutral hydrogen data. By the end of the day we located and measured several radio sources in the Sagitarius region. And we made a systematic scan almost perpendicular to the Milky Way galactic plane, in order to measure neutral hydrogen while pointing away from and in the plane. A more detailed discussion follows later in this post.
5. Gary tested the setup of the newly installed auto tuner for the FT-897 in the bunker ham station. With some adjusting and checking of cable connections, the tuner was found to be functioning OK. Gary took the opportunity to operate K0PRT in the QSO Parties this weekend for Kansas, Ohio, Hawaii, and for the US & Canadian islands, making about 30 contacts, on SSB and CW, on 40, 20, and 15 meters. Signal reports were mostly good, which seemed to indicate the combined FT-897 + tuner system is working OK. Gary wrote some Guidance Notes for using the tuner, and left those next to the tuner.
6. We received 20 QSL cards in the mail from the Open House special event station. Myron passed them on through Ed to Gary. Gary responded to all of them, and sent in the mail our QSL card responses to all by Monday.
Next are some photos of our work. Then follows a more detailed discussion about the SpectraCyber observations with the 60-foot antenna.
SpectraCyber observations with the 60-foot antenna
Rich brought the SpectraCyber 1420 MHz Hydrogen Line Spectrometer, to follow up on the successful observations we started to make with the 60-foot antenna during our Open House 2 weeks before. We used the System 1 pointing system. I later joined him by mid afternoon, after I finished my other work, and this is a report of what we did.
We started by searching for several sources with flux density values higher than 200 Janskies. However, at first no sources were found. The plane of the Milky Way was at that time very low along the southern horizon. There were few strong sources on our list available to look for at that time.
A little later, we just about ran into the Milky Way without looking for it, when the galactic plane rose higher. The signal trace of the SpectraCyber indicated the change: pointed away from the galactic plane, the signal trace stayed near about 3 volts, varying probably with noise, but not by more than a volt. Once pointing at the galactic plane, the voltage trace increased from about 5 to 7 volts (up to about 4 volts above the noise floor). The signal consistently showed a peak at about the center of the trace, at about the frequency of neutral hydrogen. We have not calibrated the SpectraCyber, and so we don’t exactly what frequency we were peaking. (The actual spectral line frequency is 1420.40575 MHz. And we may be seeing some doppler shift in our measurement.)
We then looked for several strong sources in the Sagitarius region, which by then had risen. We successfully found several, including:
Sagitarius A, the center of our Milky Way galaxy. The radio emission is thought to be from the secondary effects of a black hole there.
CTB 37, a supernova remnant about 20,000 light years away (see https://www.nasa.gov/mission_pages/chandra/ctb-37a.html.) Our signal trace showed three peaks through most of our scans. Our interpretation is that the central peak is the original supernova remnant. The other peaks would be the doppler-shifted material outflowing away and towards us, following the supernova explosion.
The Sagitarius Star Cloud Messier 24, with a colder hydrogen cloud closer along the line of sight that absorbs some of the M24 hydrogen signal. This is the radio source Tony Bigbee pointed to during our Open House 2 weeks earlier. The signal trace has a distinctive dip, which had been identified in data from the Parkes Observatory in Australia. And as Tony has discussed, was used in the past by the RASDR2 team as an engineering detection test. The dip in signal is interpreted as a hydrogen cloud along the line of sight that is colder than the background source. It absorbs the background signal and then reradiates it out, but in all directions, hence the net signal to us is reduced. We used the RA & Dec location coordinates recorded during the Open House. We found the source again without difficulty.
We used the System 1 computer display to read the angles our 60-foot antenna was pointed to. The display showed coordinates in both azimuth & elevation (Earth ground reference), and Right Ascension & Declination (celestial sky coordinate reference). We turned the antenna with the manual steering controls. At this time we do not have automatic tracking ability. But we were able to reasonably stay on our targets with continual manual adjustments. What we more often did was we found our source, then allowed the antenna to scan at the set elevation as the Earth rotated, and as a result get a short scan along a line of Declination. We then moved the elevation up and down slightly, to see differences in the scans a little north and south. We used this technique also to hone in on targets.
We then manually scanned across the Milky Way galactic plane, to obtain a slice from 16 to 20 hours Right Ascension, along the declination of -05 degrees. We stopped at intervals of 30 minutes Right Ascension (e.g., 17h 00 min, 17h 30 min, 18h 00 min, …), to let the SpectraCyber take full scans.
Our scan cut a steep acute angle through the width of the galactic plane, going across the constellations of Ophiuchus, the north edge of Scutum, and the southern part of Aquila. We therefore started and ended at angles pointed “above” and “below” from the galactic plane, and scanned across the galactic plane in between.
Since we were pointing to the southeast (and not due south), if we moved azimuth while maintaining elevation, the declination still changed. And so to keep on the -05 degree declination line, we had to adjust azimuth and elevation together.
DSES Science Meeting August 27, 2018 Follow Up
On the following Monday we had our monthly DSES Science Meeting at the home of Rich Russel.
At the meeting we discussed the observations we made with the 60-foot antenna two days earlier.
Tony Bigbee then also presented deeper details about his RASDR4 (Radio Astronomy Software Defined Radio). And he gave us more background about the earlier RASDR2 observations of Messier 24, with the dip in frequency. And he showed how he researched the earlier Parkes observatory data to find useable results and plots for us to compare to.