DSES Science Meeting – November 26, 2018

These are the presentations from our DSES Science Meeting on November 26, 2018.

Dr. Richard Russel reported on the latest results from the Milky Way galactic rotation rate observations of November 16.  Also, he compiled all of the observations of individual radio sources done with the 60-foot antenna with the Spectracyber 1420 MHz receiver.  He includes descriptions of the objects and photos, as well frequency plot observations.

DSES Science Meeting Dr Russel 11-26-18

 

Dayton Jones K6DJ talked with the group about Small Antenna Calibration at JPL.

Dayton Jones Science Meeting Presentation 11-26-18 DSES_ant_cal_v2

DSES Science Meeting, October 22, 2018

DSES Science Meeting 10-22-2018                   Meeting Notes by Bill Miller

Location Rich Russel’s Residence, Colorado Springs

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

Meeting Schedule: 

  • 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.

Galaxy Observations:

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.

DSES Science Meeting Presentation October 22, 2018 [Please click to view.]

 

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.

Figure 1 Example of a Mollweide Projection

Rich suggests that anyone going down to observe should measure some of these same sources and get data to compare their results.

 

Skip Crilly 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.

 

Additional Considerations:

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
    1. Started with Floyd’s list
    2. Added the 1420 MHz sources from the book “Tools of Radio Astronomy” by K Rohlfs and T Wilson.
    3. 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.
    1. Used Spectra Cyber
    2. Used system 1 pointing
    3. Used the new setup with the cavity filter
    4. Limit switches are set at +/-15 ether way of north. CCW to 345.  CW to 015.
    5. Gary got great pictures of the event.
    6. Need screen print capability to capture the Spectra Cyber parameters display.
    7. The Spectra Cyber SW is easy to take the data and use it.
    8. 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.
    9. 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.
  • Next Observation Trip. Need a couple of nights.

DSES Science Meeting Slides – September 24, 2018

These are the slides from Dr. Richard Russel’s presentation about the radio astronomy observations conducted at the Plishner site during the previous Saturday, September 22. The observing period was chosen for Saturday afternoon, when the Milky Way around the galactic center was starting to rise high enough in the east.  Observations were done using the Spectracyber at the 1420 MHZ neutral hydrogen I (HI) frequency.

Goals for the observing included 1) using our in-house Radio Astronomy Guide as an observing reference, 2) seeking strong enough sources listed in our guide that could serve as calibration references, 3) scanning perpendicularly across the plane of the Milky Way to observe changes in hydrogen signal while pointed inside and outside the galactic plane, 4) starting a series of doppler shift measurements along the plane of the Milky Way at galactic longitudes 10 degrees apart.

Some sources were found, but some were not. Among those found were Centarus A, Sagitarius A, and Virgo A.  A number of peaks in the hydrogen signal were seen where we didn’t have any reference information that sources were present. The scan perpendicularly across the galactic plane showed the higher concentration of hydrogen in the galactic plane. We likely also detected the weaker signal of hydrogen known to be above and below the plane in certain regions.  For this observing set, some sources like Sag-A were so strong that they oversaturated the voltage scale we had initially set.  Doppler shifts were measured at 5 points, 10 degrees apart, along the galactic plane.  Please see the slides for details.

Please click the link to see the power point slide show.

DSES Science Meeting 9-24-18_revised

On the site for the observing trip last Saturday were Rich Russel, Jay Wilson, Gary Agranat, and Steve Plock.

Radio Telescope Site Work & Science Trip – August 25, 2018

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.

Ed and Steve replaced the outflow hose from the outer sump pump. The new hose has a more robust thick wall to protect it.
Steve fabricated a new manhole cover for the outer sump. It is made of aluminum, and is much easier to handle than the original steel cover (seen leaning against the wall). The holes allow water runoff to flow into the sump during rains.
The exit of the sump outflow hose reaches well away from the ramp area.
Dave Molter devoted the afternoon and evening to continuing the repair of the ramp wall. Here he is drilling holes for the steel reinforcement bars.
Cutting the re-bars to suitable sizes.
Mixing the cement. Dave brought 20 x 60-pound bags of cement and cement blocks to continue the wall repair.
View of the wall repair work, late into the afternoon.
View of the wall repair work, late into the afternoon.
View of the wall repair work, late into the afternoon. You can see by how much more the wall has been extended.  One purpose of the wall is to control the erosion of the soil on the side, and prevent rain runoff with sediment clogging the sump pump at the base of the ramp.
Some rain showers passed just to the south late in the afternoon, as was in the NWS forecast.
Dave stirred the cement inside the blocks, to eliminate the air pockets.
Dave worked on the wall until sunset, and used all of the 60-pound cement bags he had brought. It was a lot of physical work.
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.

The SpectraCyber display showing the signal we saw at the location of Sagitarius A. The scan traces frequency from 500 KHz below to 500 KHz above the 1420 MHz neutral hydrogen frequency. The vertical axis measures the strength of the received signal, in volts.  Sag-A is believed to be a super-massive back hole at the center of our galaxy. The radio source is thought to be created by the secondary effects of infalling matter at the surrounding accretion disk, and perhaps also from material ejected at the rotational poles.
Our scan at the location of CTB 37, a supernova remnant about 20,000 Light Years away in our galaxy. We think the original star that exploded as a supernova is the central peak. The two other peaks at offset doppler shifts would be the shells of gas flying towards and away from us, from the explosion.
The Sagitarius Star Cloud, also known as Messier 24, with a colder dark gas cloud closer along the line of sight, absorbing some of the hydrogen signal from M24. This is the object Tony Bigbee observed during our Open House.  We were able to locate it again without much difficulty, using the coordinates we recorded then.
A composite image showing a chart of the part of the Milky Way we scanned across. Shown with it are example signal traces away from and in the galactic plane. The shaded blue areas on the chart are where the Milky Way is in visible light. I wrote in red the path of our scan.  Also written in are the locations of Sag-A, CTB 37, and M 24. (Click for a full sized image.) Notice that our scan cut across an apparent gap in the visual Milky Way, around 18 Hours RA. But we saw an increase in neutral hydrogen already by 17 H 30 minutes (to the right, earlier in our scan). That indicates the apparent gap is just caused by intervening dust blocking the visible light of the stars. The radio measurement of neutral hydrogen over that area shows the galactic plane is in fact there.
A view of the 60-foot antenna while we were scanning across the Milky Way. A rain shower was passing just to the south.
Rich Russel recording notes during our observations.
We saw a rainbow as Rich left.
QSL cards we received in the mail from our Open House special event station operation. : )
Our current ham radio station set-up in the bunker. The auto tuner is below the Yaesu transceiver and is functioning normally.  For this location we have dipoles for 160 and 80 meters, and a multi-band trap vertical antenna for 10, 15, 20, 40, and a portion of 80 meters.  The antennas are tuned well enough that we don’t require tuners for most of the spectrum on those bands.
60-foot antenna, in stowed position.
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.

Tony Bigbee with his RASDR4 (Radio Astronomy Software Defined Radio), at the DSES Science Meeting August 27, with Steve Plock’s 10 GHz mobile antenna.

 

– 73, Gary Agranat, WA2JQZ

Observations using the 60-foot Dish during the Open House, August 11, 2018

Editor’s note: During the DSES Open House on the weekend of August 11, 2018, three receiver systems were tested on the 60-foot dish antenna. Dr. Richard Russel reports on their successful results, and he shows what we see in our data plots. Some highlights to point out:

  1. The Spectracyber definitively observed the neutral hydrogen of the Milky Way as the beam width completely crossed the galactic plane.
  2. The RASDR4 observed a known neutral hydrogen radio source, which has a closer cloud along the line of sight that absorbs some of the hydrogen signal. The distinctive signal feature is known from published data by the Parkes Radio Observatory in Australia.
  3. The RASDR2 detected a 1296 MHz beacon set up at the home of a member about 80 miles away.  This is our first definitive detection of a beacon at 1296 MHz.

-Gary Agranat, website editor.

 

Open House Observations using the 60-foot Dish Antenna

The DSES and Society of Amateur Radio Astronomers (SARA) teams installed three different receivers onto the 60-foot dish during the open house.

 

Successful Installation and Testing of the DSES Spectracyber Neutral Hydrogen Receiver.

The Spectracyber was installed on the 60-foot dish during the DSES Open House on August 11, 2018.

The Spectracyber measures 1420.406 MHz +- 600 KHz. The observation was taken while passing the galactic plane at RA: 19hr 5 Min, Dec: 6 degrees 0 Min.

The observation shows a significant signal to noise ratio as seen below.

Follow-on observations will allow for measurement of the rotation rate of the Milky Way and Solar System!

 

RASDR4 Receiver Successful Observation of Hydrogen Absorption Line

Tony Bigbee used his RASDR4 on the 60-foot dish to observe this hydrogen absorption line at RA: 18.15hrs, Dec:-20 deg.

This target is a hydrogen source with a cloud of material between the source and Earth that absorbs the hydrogen energy resulting in a drop off of signal as shown below.

1296 MHz Beacon Observation using a RASDR2

Bogdan Vacaliuc installed a RASDR2 onto the 60-foot dish and was able to observe the 1296 MHZ beacon at Ray Uberecken’s house, about 80 statute miles distance to the west-northwest. This observation helped verify the azimuth pointing accuracy of the 60-foot dish.

 

Greenbank & Haswell plots of simultaneous observation of NRAO 5690 on August 15, 2018

The following is a comparison of simultaneous observations made on August 15, 2018 of the astronomical radio source, NRAO 5690.

The first plot is an observation made by Skip Crilly at the 4o foot radio telescope at Greenbank Observatory in West Virginia. The second plot is an observation made by Steve Plock at the DSES Plishner 60-foot antenna in Haswell, Colorado.

Greenbank observation by Skip Crilly of NRAO 5690, on August 15, 2018.
DSES Plishner radio telescope observation in Haswell, CO by Steve Plock of NRAO 5690 on August 15, 2018.

NRAO 5690 is a catalogued supernova remnant (SNR), with the celestial coordinate location of 18 hours 35 minutes Right Ascension and -7  degrees 20 minutes Declination. It is known to have an apparent radio brightness of 90 Janskies at 1.4 GHz *(1).

Each observation was made by Drift Scan. Drift scan is fixing the azimuth (left-right) direction of the antenna, and scanning the sky as the Earth rotates.  For each dish antenna, the elevation above the horizon is also fixed. As the Earth turns (at a quarter of a degree per minute), each antenna can detect radio source objects within its sensitivity, as the objects cross the beam width.

The observation at Haswell was done during a 42 hour drift scan at -7.6 degrees declination, in support of the joint SETI (Search for Extraterrestrial Intelligence) work between DSES and Skip Crilly *(2).  The dual plots show we are observing the same astronomical object at known pointing angles, and is a good verification of the two systems observing together.

 

1. Reference: NRAO VLA 1.4 GHz survey.

2. Geographically-spaced Synchronized Signal Detection System” by Skip Crilly.  Presentation on June 11, 2018 at the Society of Amateur Radio Astronomers Conference Green Bank Observatory, West Virginia, USA