Handbook of RATAN-600 Continuum observer, ver.0.3 (Oct 1998)

  1. Antenna RATAN-600 and techniques of observations
  2. Ephemerides and time service
  3. Problem of "8-points in angle of place"
  4. Arrangement of radiometers horns in feed-cabine N1
  5. Observations with "South" in lower and upper culminations
  6. Calculations of index situation of focus
  7. Old variant of the registration program
  8. The new registration program
  9. Data-reduction of observing F-files
  10. Archive of observations of feed-cabine N1
  11. Current ajustments and antenna pointing
  12. Parameters of radiometers of feed-cabine N1
  13. Database CATS supporting system of astrophysical catalogs
  14. Flux calibration observations in continuum
  15. Spectral points of secondary calibrators
  16. Principal formula for data-reducting of calibration sources
  17. New parameters of calibtation sources
  18. Examples of measurements of calibration sources
  19. What and how the observator must do


send responces or comments to:
Trushkin Sergei Trushkin
Verkhodanov Oleg Verkhodanov
Chernenkov Vladimir Chernenkov

Here all references are to Russian files now (27/10/98).

1. Antenna RATAN-600

Radio Astronomical Telescope Academy Nauk (science) of Russia is one of the two big telescope of Special Astrophysical Observatory. BTA and RATAN-600 are largest optical and radio telescopes in Russia.

RATAN has seen 'first light' from source PKS 0521-36 12 July 1974 . Since more 50000 observations were caried out in continuum. Main advantage of the telescope is multi-frequiency (1 - 31 cm wavelength) and high bright temperature sensitivity.

Proposals for observational time we ask to send to KTBT KTBT.


Blank of proposal on observation

Schedule in second half of 2006


Antenna of RATAN radio telescope consist of 576-m circle of 895 elements (2 x 11.5 m), which could use as 4 independent sectors (225 elements) of that reflector (named: North, South, West and East). Three different feed-cabines (N1,2, 3) with secondary mirrors could simulteniously collect radio emission from these three sectors and be used in programs of contiuum, spectral and solar observations. With central rail-way ratation circle the feed-cabines could be move in any of 12 fixed azimiths. But in 1997 only azimuths 0, 30, 180 and 270o can be used in observations.

In the end of 1985 a new conical mirror and feed-cabine N6 was firstly used. That feed-cabine aloows to collect radio emission from whole circle, but range of source declinations limited in this regime the zone of zenith distance z=±6o (or Dec: 38-49o ).

View of RATAN-600 from ratan.exe by S.Trushkin

Common plan of telescope (program ratan). Each element of image has reference of describing text, use click of mouse.


Geographic coordinates of the RATAN center, as measured with astrometric observations in 1968 Juanary:
latitude (phi) 43o 49' 52".75±0".16
longitude -02h46m22.1s or -41 35' 31".5
hight from sea level 970 m
A0 H = (90 - phi) + delta = 46o10'07".25 + delta

A180lc H = -(90 - phi) + delta = -46o10'07".25 + delta

A180tc H = (90 + phi) - delta = 133o49'52".75 - delta

Closing angles by mountains:
Azimuth Hmax Directions
0o 2o16'52" in North
90o 2o07'00" in East
180o 3o19'30" in South
270o 2o39'00" in West

Techniques of observations

  1. Usualy the transit regime of source through unmoving direction diagram (beam) of telescope. That regime is fitted for big list of sources or for survey on fixed elevation.
  2. Regime of 'unmoved focus' with one sector is fitted for massive observations of sources in range of nearby declinations: 2-3o for DEC = 0 and 10o - for declination: -30o. In this case feed-cabine became in the same position, thus no movement or ajustment of horizon. Accuracy of determination of RA and DEC improves to 3-10".
  3. Since of 1996 the current regime of 'sliding' with effective time of collection of 60-100 second. If you know coordinates of object you could decrease threshold of determination of radio emission. his regime could use anly with North or South sectors.
  4. Regime "Zenith" is observation with feed-cabine N6 and whole circle, but is not in the plan of 1997.
  5. Regime "Atmosphere" is vertical cross-cuts for detrermination absorbtion in atmosphere, it needs only 1-2 cross-cuts-removing of antenna from 5 to 30o.
return

2. Ephemerides and time service

In MS DOS efemerides of sources could be calculate in program EFRAT , created in SpbITA. In database of EFRAT there are two files of parameters from 1976 to 1990 fd7690 and file jd9000 from 1990 to 2000. Two editable files efrat.ini and obser.dat allow to change location of the observatory and time zone. Ephemerides of the Sun, Moon, planets and Galiley satellites of Jupiter also as stars and radio sources could calculate from EFRAT. In Linux the programs of efemerides epoch . or task preparation of observation could be used.


Here galactic and equatorial coordinates tramsformation figures are given.
Time service of RATAN-600 outputs sideral seconds and impulses of minutes with time codes for feed-cabines. These signals are coincided with local sideral time, recalculated from coordinate time UTC, using of sideral time program (stime) having accuracy of 0.0001s. DeltaUT1 and deltaT can be received from Time service or from Astronomical Annuals. In table UT1-UTC1 you could find values these corrections in 1988-1996.

In two figures the correction values UT1-UTC1 are given for period 1979 - 1996.

These corrections are smaller one second. Be careful in two dates: 31.12 - 1.01 and 30.06 - 01.07. Thus for determined azimuth

Ts(cul) + deltaUT1 = RAef - nutation in RA = mean Ts.
If it is so, than observation were carried just in needed azimuth, and a horn of radiometer placed in correct focus (using a focal motion of carriage of radiometers).

It should be noted, that in North sector railways have systematic error in limits of 10-15 mm, thus "correct" position of carriage changes likely. But as usualy observer uses the same position of carriage in sets of observations. So some years position of the horn of 7.6 cm radiometer, '1058 mm' was correct for all range of elevations.
In figure plot of changing of moments of source culminations with fixed position of horn, recalculated on value of carriage, in dependence on the focal distance.

At least, for addition of records, received in different epoch, this records could carry to same epoch or to take into account changing of nutationin same period.

Program jdate [dd/mm/yy] or [jd] outputs Julian day or gives current date from Julian day, (plus day of weak and deltaUT1 in 1980-1996 with accuracy of ±0.02s) .

The programs stime (DOS) and stm calculate mean sideral time on any date (usage: stime [hh] [mm] [ss] [dd/mm/yy] ). This program takes into account passage to summer time.

Remember: in summer time correction to Greenwich time is 4 hours, for winter it is 3 hours. From 1996 this transfer became to do in last sunday of October, as in most of European counties.

Here the plot of nutation in Right ascention are shown in 1979-2001. It could be used for estimate of changing of nutation.

Refraction was involved in account of horizon coordinates as in table:

Table radio refraction
Z H Refraction
0o 90o 0
5 85 0'06"
... ... ...
84 6 10'00"
85 5 11 42
86 4 14 00
87 3 17 18
88 2 22 28
89 1 30 30
90 0 38 42

This dependence could be roughly fitted by formula

Ref(opt) = 58".3*tg(z) - 0.067*tg3(z)
Ref(rad) =1.2*Ref(opt)
Ref(rad) =69".14*tg(90-h) (for 20o < h < 90o )

Plot of radio refraction near RATAN-600 and its approximation of by 5-power polynome in refra (DOS).

Number of antenna elements in dependence on elevation of source: Second column gives horizon size of antenna, from formula

d = 2* 288.5* sin(N/2*0.4o)
-
H N el. d (m) 1.38/d
0o 164310-
10 166 312 9.1" (11")
20 172 326 -
30 178 336 -
40 190 355 -
50 206 380 7.5"
55 224 407 -
57 225 408 6.94" = one
60 235 422 sector
65 256 461 -
70 280 478 -

beam of RATAN sector antenna
Calculated beam of RATAN North sector antenna at 7.6 cm (H=51o). Horizon HPBW (in Azimuth) is equal 60", and vertical one - 15'. Base is equal 10 % of maximum value.

3. Problem of "8 points in angle of place"

AK-adjustment group discovered systematic difference in Geodesic and autocallimation adjustments: in general the AC angle of elevation smaller geodesic one on 6-8 points. Now for short waveband observations this correction needs to involve because of as observations (1978-79, 1995-96) show the gain of antenna decrease in two times at 2 cm wavelength without this correction. return

4. Arrangement of horns feed-cabine N1

Carriage of feed-cabine N1 had five configuration at least:

1976 to 1980 program carra80

1980 to 1992 program carra89

1993 to 15.03 1994 program carra93

1994 to 04.11 1996 program carra94

1996 to now program cavrra96

(by S.Trushkin)
Current and last year carriage of feed-cabine N1

Velosity of moving source image in focal line defined by formula, coincident with direct measurements:


			    21.23*cos(delta)
North                  V  =  ---------------    mm/s
			      1 + cos(H)

South +flat mirror      =  10.537*cos(delta)  mm/s

Geometric optics gives
	V  = 15*cos(delta)*(r0=288470mm)/(1+cos(h))*sin(1")=
	     =20.92*cos(delta)/( 1+cos(h) ) mm/s

velocity of source in focal line

5. Observations with "South" in lower and upper culminations

South sector could be used as usual sector, and as three-mirror antenna with flat reflector. This beam is a "fan" or "knife-edge" aligned in vertical plane. This South and flat mirrir antenna and new feed-cabine N5 could be used for azimithal observations (from A=-30o to +30o). Below the figure of RATAN southern railways are given. Observations of sources limited declinations range +46o - +90o in lower culmination and declination range +75o - +90o in both culminations. Limitation are from shadow effects of flat reflector.
|---------------------------------------------------------------------|
h=90o                                      flat         h=43o50'    h=0
|       h>60o                                |  h<60o     |           |
|                                            |            |           |
|                                            |            |           |
|  Fcalc 20       40       60       80      100      120  |  140 m    |
C--------|--------|--------|--------|--------|--------|---|----|------| S
|                                            |            |           |
|           upper            c u l m i n a t |i o n       | lower cul.|
|                                            |            |           |
43o50' dec:                                  75o         90o         46o
|---------------------------------------------------------------------|
Again formula for elevation with South sector.
H(lc) = DECeph - 46o10'08"
H(uc) = 133o49'52" - DECef
With one sector of RATAN the "Up-zenith" sources can be observed: 90o < H < 97o. In this case feed-cabine has negative focus distance, but source elevation must be calculated for diametrical azimuth.

6. Calculations of index situation of focus

For calculation of position of feed-cabine index on radial railways the following formula is used
deltaR = Fcalc - deltaF - Ri
where deltaR is distance in mm from the closest geodesic sign to center from feed-cabine; deltaF - experimental addition to calculated position (as usually being fitted by linear or quadratic polynomes); Ri - distance in mm from center of circle to the geodesic sign. The focal distance measured from 6-7 calibrated geodesic signs.
In North railways :
Geodesic signs distance
1 20014
2 40000
3 60022
4 80011
5 100011
6 120014
7 139996
Geodesic signs 1-th was 20024 before 1995, 6-th was 120005 before 1995) 7-th was 139983 before 1995.
Search of focal distance of North sector (feed-cabine N1) is made every time after AC-adjustment.

Distance between imaginary focus and index of feed-cabine N1 (S. Golosova)

15.09.82 4884 mm

03.11.89 4869 mm

19.01.95 4862 mm

05.03.97 48?? mm

For N2 : 4926 mm

Plot of calculated focus Fcalc via elevation, as output by program focus. focus from of a sector antenna
Fcalc = (1-F){Rmax - 445.0(1/cos(h/2) -1) }, where

Rmax = 288470 mm;

Rmin = 287530 mm;

F = (1 - K cosh)/(1 + cosh);

K = sqrt(1 - (Rmin/Rmax)2).
For elevation 5o 1 mm of focus is equal 33" in elevation
For elevation 10o 1 mm of focus is equal 15"
For elevation 20o 1 mm of focus is equal 7"
For elevation 44o 1 mm of focus is equal 3"
For elevation 75o 1 mm of focus is equal 1"
For elevation 95o 1 mm of focus is equal 0.5"

Plots elevation of source h and hour angle t from current declination for antenna azimuths: 0, 30, 60 and 90o.

Calculation of beam and transverse aberration using algorithms by A.N. Korzhavin, rewiting in C by O. Verkhodanov and S. Trushkin. Thus any beam for real observations could be calculated.

There are version for LINUX aberr , gs and be.
and for MS DOS aber and gst.

Plot of transverse aberration in dependance from shift distance along the carriage of feed cabine for several North sector elevation.

Plot of longitudinal aberration in dependance from shift distance along the railways of feed cabine for several North sector elevation (red - elevation 17o, yellow - elevation 77o, green - elevation 87o).


7. Old variant of the registration program

Old registration or data collection worked from 1987 to 1994 and used the 'SM' computers with NTS system.
return

8. The new registration program

Here new data collection is the complex for registration and management of continuun radiometers "Continuous" was created for Linux and local intranets
About this new system you could read here . PC ref1.ratan.sao.ru are placed on feed-cabine N1 (600 m from server). All observers login as user: obs , passwd: (ask ratan super-user). The user obs works with menu of program input. He creates packet (as a rule named by real name of user). For example, satr. He could edit the packet input positions and output with saving as . Then observer must send task-packet for data-registration program rr. Ephemerides of planets, Sun and Moon must be calculated by efrat . In 1996 October importing of text files of task of observations in task-packet using PLATEX fromat.

Import of files could use for remote preparation and correction of observing task-packet.

With utility prit obssatr file obssatr.p would be cteated, available for viewing. Then this files will send to user e-mail address.

Example of record of source PKS 1830-21  from a  such file obsbur.p .
-----------------------------------------------------------------------------
 Number		  3(o)
 File		 r6906p1830-21		Feed-cabine		1
 Source		 1830-210  		Observer	Bursov
 Date		 06 09 96		Azimuth		    0d00m0.00s
 Elevation	 25d09m23.639s		Horn_WL in Focus	2.70
 Elevation_ef	 25d09m23.640s		Horn			w
 RA 1950	 18h30m41.010s		Carriage		940.00
 Dec1950	-21d05m32.000s		Variant/Type		a/d
 RA_date	 18h33m29.090s		Discret sec		0.10
 Dec_date	-21d03m11.457s		Focus mm		147985.594
 Nutation in RA	 0.211s			Start location		940.00
 Siderial time	 18h33m28.879s		Velocity mm/sec		0.000
 Local    UTC	 20h42m54.855s		V(car)/V(src)		0.00
 Start    time	 18h30m58.88s		Time before RA m	2.500
 Stop     time	 18h35m28.88s		Time after  RA m	2.000
-----------------------------------------------------------------------------
 Channel Wave_cm Stocks Regime	Clv_K	Gain Tau Compress W_shift E_shift sec
  2	 2.70	   I	BS	1.35	+ 5  0.00    1	  0.00	-9.23
  4	 7.60	   I	SH	0.41	+ 4  0.00    1	  11.35	 13.70
  5	 13.00	   I	SH	2.00	- 4  0.00    1	 -40.39	-40.39
  9	 31.00	   I	SH	1.90	- 5  0.00    1	  66.25	 66.25
  3	 3.90	   I	BS	1.00	+ 3  0.00    1	 -14.62	-29.81
  8	 1.38	   I	BS	1.70	+ 5  0.00    1	 -4.71	-80.96
-----------------------------------------------------------------------------
Program rr loads current packets, sent by each observer.

Program vis or xvisn are used for visualization of observations . Example of visualization of chanals 2, 3, 4, 5 and 9 with calculations of dispersion and without new time synkhronization:

xvisn -s -g -c "2 3 4 5 9" ref1
Program vis is used at ref1 as a rule, and programs visn and xvisn work under X-windows on any network PC. Program visn needs "s" and owner = root, because it was created with svgalib.

In focus of cariage horns could arrange automatically from packet rr in the begining of task. The remote compensation of radiometers levels are included in the management:

comp -l lambda_cm.
Note: it could load only in ref1.

Recorded files load down in archive at server (ns.ratan.sao.ru) /PUB/archive/ref1/. These multi-frequency FLEX-files named by format rYMDDaHHMM-DD, where

r - sign of records in continuum

Y - last figure of Year

M - mouth (in 16-mal system 123456789ABC)

DD - day

a/p- 'ante meridiem' or 'past meridiem' of the record. These signs follow the possible twice observations in day.

HH - source name consists of hours and minutes of RA (here B1950)

MM minutes if RA

- - sign of declination

DD - degrees in declination

p - a flag of files from data recording system of based on signal processor four-channal output of 31 cm-radiometer (pulsar.ratan.sao.ru).

These FLEX-files could be transformed in f-files by program fl2f .
For example: by fl2f r* -dos -c comp files for data-proccessing in MS DOS with compression in text-file comp.

In special files /users/obs/lib/chan/chanst main parameters of radiometers and parameters of registration: channels, temperature steps of noise calibration signals, arrangement of carriage, regimes and so on. Observer can create new type of observations with defined special perameters.

Transformations equatorial and galactic cordinates could be made by program epoch in Linux and fad in MS DOS.

9. Data-reduction of observing F-files

Interpolation for changing time discrete interval could be made by intv
intv -d step filename > new_file
(O. Verkhodanov)

If observer wants data-reducting with f-files in MS DOS or (dosemu in Linux) he could use program prat.

Example of prat output:

Usage:

prat filename or prat and use menu.

prat *? (wild cards use for list of files in current directiry)

prat file1 file2 file3 ... (view of n < 10 files)

prat @textfile import of text files, including colomn of float numbers.

( by T.Sokolova & S.Trushkin)

List of f-files working programs current data-reduction of RATAN f-files include more than 80 different programs, created by O. Verkhodanov in Linux. His interactive program fgr works under X-windows and has detailed manual of users.
Usage fgr file1 file2 ... [flags]
For viewing of f-files heads dff filenames could be used. return

10. Archive of observations of feed-cabine N1

Archive of continuum observations consist of 140 magnetic tapes. From 1982 to 1987 only multi-frequency files were archived, which could be data-processed with old program PRF for S. Since 1991 new archive program ODA are used, 38 magnetic tapes were rewrited an DAT-tapes (since 1989). OLD records are accessible only by way MERA-685 -> kermit-> RATAN-server or by way PCSM- MS DOS at nova.ratan.sao.ru and ares.ratan.sao.ru. Now archive rewrite on DAT tapes every 1-2 weeks after observations.

(S.Pavlov, V.Kononov)

11. Current adjustments and antenna pointing

Since 1993 August to 1995 March the geodesic adjustment antenna base was used in observations. (T. Plasnina).

Now with fixing of surface of main mirror elements of North sector Accuracy of the surface is better 0.2 mm.

In 1996 September new AC-adjustment of North sector. Search of "8-points" shows value -4 point for angle. return

12. Parameters of radiometers of feed-cabine N1

Wavelength Frequency 1sigma ( K) tau=1sec Band (MHz) Tsys
1.38 21.7 0.015 1400200
2.70 11.2 0.004 1000140
3.90 7.7 0.006 700140
7.6 3.95 0.0025 500 40
13.0 2.3 0.025 250 60
31.1 0.985 0.025 100100

( head of Continuum radiometers lab: N.A. Nizhelskij)

Radiometer at 31 cm was equiped by output to signal processor and 4 filter channal with band 30 MHz in 1996 March. (P.A. Freedman) This processor placed on PC pulsar.ratan.sao.ru and remove the impulse interference in each channals "on-line". High rate (100-1000 Hz) of data-recording allows to use this equipment for pulsar observations, as shown in probe observation of PRS 0950+08 and PSR 1133+16. The 8-channals back-end of 13 cm-radiometer is prepared and will be arrange in 1997. This system is very effective for removing of impulse or stationar interferences.

New data-recording system include regime of "sliding", allowed to follow of source during 100-150 second.

13. Database CATS supporting system of astrophysical catalogs

logo CATS On server cats.sao.ru database CATS - supporting system of astrophysical catalogs, see CATS preprint . It includes procedures of selection and matching from radio or mixed catalogs. There are the self-sufficient descriptions of every main catalogs: NVSS, FIRST, TEXAS, MASTER LIST, MIT-GREEN BANK, 6C, 7C, MCG-VV, PMN, NAIC..., more 150 catalogs in CATS (O.Verkhodanov, S.Trushkin, V.Chernenkov) Two version Kuehr et al. (1979) about spectral data of 1842 sources and its short version Kuehr et al. (1981) about 518 sources and PKSCAT90 are could be use for obtaining flux data at RATAN continuum radiometers.

CGI-Program in CATS could plot "on a fly" GIF-figure of a spectrum of a source from catalogs of Kuehr at al (1979, 1981), PKSCAT90, Supernova remnants and any radio source, searched for in radio catalogs.

Here the spectrum of calibrator source 3C286 = 1328+30.

Spectrum of 1328+30

CATS database contains catalog of point IRAS sources (~250000), catalogs faint sources (450000 and |b| >10o). Dr D. Leisovitz presents kindly to N.V. Bystrova atlas of IRAS, on 8 CDs, where the FITS-maps ( size 12.5o*12.5o) are at all four bands of IRAS of whole sky. CATS authors consider to add them in the database.

Sample of sources from VLA-list (812) of calibrator sources, brighter 2 Jy at 20 cm and all point 3CR-sources from this list could be useful for coordinate or focus adjustment of antenna. return

14. Flux calibration observations in continuum

Common accepted scale of calibrator source are "Baars'scale"

J.W.M. Baars, R.Genzel, I.I. Pauliny-Toth and A. Witzel 'The absolute Spectrum of Cas A; An accurate flux density scale and a set of Secondary Calibrators', Asrton. Astrophys., 61, 99-106, 1977.

In this paper there was established, that spectra of Cas A has accuracy 2%. Between 0.3 and 30 GHz S= 2723(Jy)*freq.-0.77 (1980.0). Spectra of Cygnus A and Taurus A are given. Precise semi-absolute spectrum of Virgo A was determined from precise relation to Cas A and Cyg A fluxes and was approximated S=285(Jy)*freq.-0.856 (good for 0.4 - 25 GHz). This spectra was used as base for relative spectra some sources with simple spectra. They are secondary standards for common day calibrations. These data are good for frequency range 0.4 - 15 GHz and seem to have absolute accuracy near 5%.

Ir was found the dependence of decreasing of flux of Cas A:

d(freq.)[%/year] = 0.97(±0.04) - 0.30(±0.04)log(freq.)[GHz]
Correction of flux density scales to Baars et al. one (1977) must be used in many cases of old catalogs. Information about these corretion factors (particular contradictive) could receivev from the following published papers:

15. Spectral points of secondary calibrators

For quadratic fitting: logS[Jy]=a+b*log(fr)[MHz]+c*log2(fr)[MHz]
Name Frequency Spectral parameters
Source MHz GHz a b c
Cas_A 1965.0 300 31 5.880±0.025-0.792±0.007 -
Cas_A 1980.0 300 300 5.745±0.025 -0.770±0.007 -
Cyg A 20 2 4.695±0.018 +0.085±0.003 -0.178±0.001
Cyg A 2000 31 7.161±0.051 -1.244±0.014 -
Tau A 1000 35 3.915±0.031 -0.299±0.009 -
Vir A 400 25 5.023±0.034 -0.856±0.010 -

Spectrum parameters of secondary calibrators

For quadratic fitting: logS[Jy]=a+b*log(fr)[MHz]+c*log2(fr)[MHz]
Name Frequency Spectral parameters
Source MHz GHz a b c
3C48 405 15 2.345±0.030 +0.071±0.001 -0.138±0.001
3C123 405 15 2.921±0.025 -0.002±0.000 -0.124±0.001
3C147 405 15 1.766±0.017 +0.447±0.006 -0.184±0.001
3C161 405 10.7 1.633±0.016 +0.498±0.008 -0.194±0.001
3C218 405 10.7 4.497±0.038 -0.910±0.011 -
3C227 400 15 3.460±0.055 -0.827±0.016 -
3C249.1 400 15 1.230±0.027 +0.288±0.007 -0.176±0.003
3C286 405 15 1.480±0.018 +0.292±0.006 -0.124±0.001
3C295 405 15 1.485±0.013 +0.759±0.009 -0.255±0.001
3C348 400 10.7 4.963±0.045 -1.052±0.014 -
3C353 405 10.7 2.944±0.031 -0.034±0.001 -0.109±0.001
DR21 7000 31 1.81 ±0.05 -0.122±0.010 -
NGC7027 10000 31 1.32 ±0.08 -0.127±0.012 -

Flux density of secondary calibrators (Baars et al. 1977)

Source Frequency [GHz]
0.96 1.42 2.30 3.65 3.90 7.70 11.20
Cas_A1980. 2809.6 2078.4 1433.7 1004.7 954.7 565.5 423.7
Cyg_A 2319.4 1563.8 952.8 536.4 494.0 211.9 133.0
Tau_A 1055.1 938.6 812.5 707.7 693.9 566.2 506.2
Vir_A 295.2 211.2 139.7 94.1 88.9 49.7 36.1
3C48 21.35 15.76 10.57 7.03 6.61 3.44 2.34
3C123 64.89 48.14 32.58 21.89 20.64 10.97 7.58
3C147 29.01 22.22 15.46 10.55 9.96 5.30 3.62
3C161 24.70 18.84 13.02 8.81 8.31 4.35 2.94
3C218 60.69 42.50 27.40 18.00 16.95 9.13 6.49
3C227 9.86 7.13 4.78 3.27 3.09 1.76 1.29
3C249.1 3.34 2.45 1.62 1.05 0.99 0.49 0.32
3C286 17.70 14.73 11.49 8.84 8.50 5.52 4.26
3C295 30.24 22.06 14.28 8.97 8.36 3.83 2.38
3C348 66.93 44.34 26.70 16.42 15.32 7.49 5.05
3C353 74.67 56.71 39.62 27.52 26.08 14.64 10.45
DR21 (5.0) - (12.1) (17.3) (17.4) 21.67 20.70
NGC7027 0.94 - (2.64) (4.77) (4.9) (6.47) 6.39

Accepted flux densities at RATAN are given in (). This scale was used for spectral catalogs by Kuehr et al. (1979, 1981): H.Kuhr, A. Witzel, I.I.K. Pauliny-Toth and U.Nauber A catalogue of extragalactic radio sources having flux densities greater than 1 Jy at 5 GHz Astron. Astrophys. S.S. 45, 367-430, 1981, and MPIfR Preprint Nr 55, 1979.

Source RA(1950) DEC(1950) Ident. Size Pol % Pos. angle
name hh mm ss.sss dd mm ss.s '' at 3.9 cm at 3.9 cm (deg)
3C48 01 34 49.832 +32 54 20.5 QSO 1.5 x 1.5 4. 113
0237-23 02 37 52.803 -23 22 06.2 QSO 2 x 2 5.9 134
3C123 04 33 55.2 +29 34 14. GAL 23 x 5 1.0 -
3C138 05 18 16.53 +16 35 27.0 QSO 0.3 x 0.3 11.8 171
3C147 05 38 43.507 +49 49 42.8 QSO 1 x 1 1.4 0
3C161 06 24 43.19 -05 51 11.8 GAL 3 x 3 2.8 104
3C218 09 15 41.5 -11 53 06. GAL 47 x 15(200") 1. 6
3C227 09 45 07.8 +07 39 09. GAL 200 x 50 4.7 157
3C249.1 11 00 25.0 +77 15 11. QSO 15 x 15 3.0 158
*1151-34 11 51 49.35 -34 48 47.5 QSO 2 x 2 1.0 -
*1245-197 12 45 45.218 -19 42 57.51 QSO <1 x 1 <1. -
3C286 13 28 49.657 +30 45 58.6 QSO 1.5 x 1.5 11.3 34
3C295 14 09 33.5 +52 26 13. GAL 5 x 1 1.5 130
3C309.1 14 58 56.64 +71 52 10.8 QSO 1.5 x 1.5 2.6 34
3C348 16 48 40.1 +05 04 28. GAL 170 x 25 7.2 25
3C353 17 17 54.6 -00 55 55. GAL 210 x 60 6.2 91
DR21 20 37 14.3 +42 09 07. HII 20 x 20 0 0
NGC7027 21 05 09.4 42 02 03.1 PN 7 x 10 0 0

return

15. Principal formula for data-reducting of calibration sources

For NGC7027 coefficient for size:
Kdisc = ( x2/(1-exp(-x2) ) where x=R/(0.6*phi05)

R - radius of source, phi05 - size of beam (HPBW):

 wavelengths       1.38   2.7   3.9   7.6    13    31 cm
 Kdisc(North)      1.20   1.10  1.07  1.02  1.01   1.0
Linear polarisation mast be taken to account for estimate of Aeff:
k * Ta = F*Aeff*Sv,
where k - Boltsman's constant, Ta - source antenna temperature; Aeff - effective area of antenna and Sv is full flux (in Jansky).
F = (1-p)/2 + p * ( cos(Xa-Xs+(270o- Xra) )2 ,

where p - power of linear polarisation

Xa - positional angle of antenna (accepted of polarization plane)

Xs - positional angle of source

Xra - positional angle of RA-axis (for Azimith 0: Xra=270o) angle are account from North to East.

F = 1/2 if source is unpolarized, as ussually. But F could change from 1 - p/2 to 1 + p/2 , thus error of measurements without polarization data are 1/(1 ± p) in Aeff or measured flux. Compilation of polarization measurements collected in paper: Tabara et al., AASS, 1980, 39, 379 - 393. Details of such measurements are given in Aliakberov et al. (1989).

16. New parameters of calibtation sources

New paper was published about Effeslberg 100-m telescope measurements of the same list of secondary calibrators: M.Ott, A. Witzel, A. Quirrenbach, T.P. Krichbaum, K.J. Standke, C.J. Schalinski, and C.A. Hummel 'An updated list of radio flux density calibrators ( A&A, 284, 331-339, 1994). In this paper most sources were shonwn to be slow variable sources at 0.7 - 21 cm wavelengths on scale 10 years, but 3C286 and 3C295. These source were used to obtaining another flux densities sources. New sources were ppropose as calibrators.

Spectrum parameters of secondary calibrators (Ott et al.)

For quadratic fitting: logS[Jy]=a+b*log(fr)[MHz]+c*log2(fr)[MHz]

Name Frequency Spectral parameters
Source MHz GHz a b c
3C48 1408 23.8 2.465 -0.004 -0.1251
3C123 1408 23.8 2.525 +0.246 -0.1638
3C147 1408 23.8 2.806 -0.140 -0.1031
3C161 1408 10.55 1.250 +0.726 -0.2286
3C218 1408 10.55 4.729 -1.025 +0.0130
3C227 1408 4.75 6.757 -2.801 +0.2969
3C249.1 1408 4.75 2.537 -0.565 -0.0404
Vir A 1408 10.55 4.484 -0.603 -0.0280
3C286 1408 43.2 0.956 +0.584 -0.1644
3C295 1408 43.2 1.490 +0.756 -0.2545
3C309.1 1408 32.0 2.617 -0.437 -0.0373
3C348 1408 10.55 3.852 -0.361 -0.1053
3C353 1408 10.55 3.148 -0.157 -0.0911
Cyg A 4750 10.55 8.360 -1.565 -
NGC7027 10550 43.2 1.322 -0.134 -

Flux densities of secondary calibrators (Ott et al.)

>
Source Frequency [GHz]
0.96 1.42 2.30 3.65 3.90 7.70 11.20 21.20
3C48 21.90 16.19 10.91 7.30 6.88 3.63 2.50 1.24
3C123 63.36 47.08 31.68 21.02 19.77 10.16 6.85 3.25
3C147 29.62 21.89 14.80 9.98 9.41 5.07 3.54 1.82
3C161 24.10 18.49 12.80 8.62 8.11 4.16 2.76 1.26 ?
3C218 61.35 42.37 26.92 17.48 16.44 8.74 6.19 3.38 ?
3C227 11.07 7.55 4.97 3.52 3.37 - - -
3C249.1 3.11 2.26 1.52 1.03 0.97 - - -
Vir_A 273.31 201.81 38.18 95.64 90.68 52.18 38.30 22.0 ?
3C286 17.20 14.56 11.52 8.92 8.57 5.53 4.22 2.49
3C295 30.28 22.09 14.30 8.98 8.37 3.84 2.39 0.96
3C309.1 9.59 7.39 5.33 3.86 3.69 2.27 1.72 1.05
3C348 69.00 46.52 28.08 16.97 15.77 7.22 4.61 2.02 ?
3C353 74.05 55.95 38.96 27.08 25.67 14.51 10.44 5.68 ?
Cyg_A - - - - 49.50 89.51 105.43 37.4 ?
NGC7027 - - - - - 6.33 6.02 5.51

From http://www.nrao.edu/~gtaylor/calib.html

(VLA) About the 1997 calibrator manual

Over the last year the VLA calibrator manual has continued to grow. A major improvement has been the addition of Q band entries for 276 calibrators. Note however, that most of the calibrators are flat spectrum and rapidly variable, so the flux densities reported here may not reflect the current level for a given source. In this revision the calibrator manual contains 3850 entries for 1044 sources. Updates are expected throughout the coming year so for the most current version of this document the reader is recommended to access the World Wide Web at http://www.nrao.edu/~gtaylor/calib.html.

Monitoring of Flux Density Calibrators

Since the planets and 3C295 are too heavily resolved for most VLA observing programs, the flux density of a small set of calibrators is carefully measured with respect to 3C295 and the planets in the 'D' configuration every few years. These more compact sources have been found to be only slowly variable (with some exceptions at the highest frequencies). Below we provide the current (1995.2) best analytic expression for their flux densities.

 Log S = A + B * Log v + C * (Log v)2 + D * (Log v)3

where S is the flux density in Jy and v is the frequency in MHz. These expressions are valid between 300 MHz and 50 GHz. Table1.
Name Spectral parameters
Source A B C D
3C48 1.16801 +1.07526 -0.42254 +0.02699
3C138 1.97498 -0.23918 +0.01333 -0.01389
3C147 0.05702 +2.09340 -0.70760 +0.05477
3C286 0.50344 +1.05026 -0.31666 +0.01602
3C295 1.28872 +0.94172 -0.31113 +0.00569
Observations taken many years prior to 1995.2 may benefit from using the adjustments below when setting the flux density of 3C48, 3C147 or 3C286.

Below are listed the RATIOS between the true and Baars et al. value for 3C48, 3C147 and 3C286 at the various frequency bands from 1983 to 1995. Multiply the Baars et al. value by this ratio to obtain the correct flux density.
Contact R. Perley or G. Taylor if you need more information. In bands: 20cm=L 6cm=C 3.7cm= X 2cm=U 0.7cm=Q.

SourceBand 20cm 6cm 3.7cm 2cm epoch
P L C X U
3C48 - 1.004 1.039 - - 1983.5
3C48 - 1.018 1.047 - 1.11 1985.5
3C48 0.95 1.02 1.04 1.06 1.10 1987
3C48 - 1.019 1.043 1.049 1.076 1989.9
3C48 0.948 1.017 1.023 1.034 1.034 1995.2
3C147 - 0.974 0.957 - - 1983.5
3C147 - 0.970 0.948 - 0.99 1985.5
3C147 1.00 0.97 0.95 0.97 1.01 1987
3C147 - 0.975 0.951 0.949 0.993 1989.9
3C147 0.990 0.983 0.974 0.999 1.046 1995.2
3C286 - 0.995 1.010 - - 1983.5
3C286 - 0.993 1.002 - 0.99 1985.5
3C286 0.95 1.00 1.01 1.01 1.02 1987
3C286 - 0.999 1.005 0.995 0.991 1989.9
3C286 0.971 0.999 1.008 1.006 0.988 1995.2

New values of flux densities for RATAN radiometers, calculated from Table 1.

Source Frequency [GHz]
0.96 1.42 2.30 3.65 3.90 7.70 11.20 21.20
3C48 21.506 16.004 10.787 7.186 6.765 3.540 2.431 1.219
3C147 28.806 21.891 15.084 10.252 9.680 5.249 3.698 1.972
3C286 17.545 14.769 11.591 8.924 8.576 5.529 4.244 2.567
3C295 30.265 22.073 14.274 8.962 8.351 3.830 2.390 0.968
3C138 10.276 8.287 6.221 4.615 4.413 2.700 2.008 1.137
return

17. Examples of measurements of calibration sources

The measurement of calibrator sources in 1987 (by Trushkin & Aliakberov) with North sector of RATAN-600

Source Frequency [GHz]
0.96 2.30 3.65 3.90 7.70 11.20 14.40 22.3
0023-26 - 10.70 5.99 5.28 4.41 2.38 - 1.3 -
0237-23 - 6.75 5.05 4.21 3.87 2.73 (2.25) 1.93 -
1830-21 - 14.00 10.90 9.90 9.99 8.55 - 6.43 5.2
0159-11 3C57 3.77 1.76 1.50 1.48 0.95 - - -
0624-05 3C161 24.20 12.50 8.90 8.07 4.22 (2.76) 2.13 1.88
0003-00 3C2 5.06 2.27 1.79 1.76 1.02 - - -
2314+03 3C459 7.82 6.68 9.74 1.54 0.84 - - -
2128+04 - 5.30 3.17 2.28 2.34 1.29 - 1.09 -
0518+16 3C138 11.25 6.66 4.71 4.15 3.00 - 1.62 -
0428+20 - 3.50 3.47 2.69 2.83 2.16 - 0.97 -
0433+29 3C123 63.70 30.90 23.50 21.05 11.51 (6.85) 6.47 3.12
0134+32 3C48 21.50 10.91 7.30 6.88 3.63 (2.50) 1.9 (1.20
2105+42 N7027 0.94 2.64 4.77 4.90 6.47 (6.50) 6.9 6.0
2037+42 DR21 5.0 12.10 17.30 17.40 21.50 (20.50) 18.7 21.2

This is experimental formula for effective area and Integral coefficient, receiving from obvsevations of calibrators in 1992 Febrary with North sector (7 groups). (by Trushkin)

Aeff( 2.7cm) = 3.072*H + 360.5 m2 ( 4o - 80o )

Aeff( 7.6cm) = 4.653*H + 574.4 m2 (20o - 80o )

Aeff(31.1cm) = 1202 -7.17931H +0.441936H2 -0.005004H3 m2

K_Jy/Ks( 2.7cm) = 1.485 + 0.0735H - 0.000727H2 or K_Jy/Ks( 2.7cm) = (3.07 - 0.0035H)*cos(Dec)

K_Jy/Ks( 7.6cm) = 0.623 - 0.0101H - 0.0001181H2 or K_Jy/Ks( 7.6cm) = (0.885 - 0.0009H)*cos(Dec)

K_Jy/Ks(31.1cm) = 0.0844 - 0.00102H or K_Jy/Ks(31.1cm) = 0.2062 - 0.000641F

In 1996 Effective area of North sector

Wavelength Aeff(m2) 1 Jansky = 100 mK =
1.4 400 0.144 K 690 mJy
2.7 900 0.326 307
3.9 900 0.326 307
7.61000 0.362 276
13.0 900 0.326 307
31.01200 0.435 230

We recommend use calibrator curves in depend of focus distance, but of elevation. Then in full range of declination such curves could be fitted by 1-st or 2-nd power polynomes. This conclusion bases on observations, but calculations.

Next steep spectrum sources could be use as secondary calibrators 0552+398, 1345+125 at long (>8cm) wavelengths. 1245-197, 1328+254, 1511+238, 2352+495 at every wavelengths. (by S. Trushkin).

New possible calibrators from Kuhr's et al. catalog

Source RA1950 +- DEC1950 +- Ident. Mag. Z
0742+10 074248.47±.01 +101832.6 ± .1 EF - -
1151-34 115149.35±.04 -344847.5 ± .5 QSO 17.5 0.258
1245-19 124545.22±.01 -194257.6 ± .1 QSO 20.5 -
1328+25 132815.92±.01 +252437.6 ± .1 QSO 17.7 1.055
1345+12 134506.19±.01 +123220.0 ± .3 GAL 17.0 0.122
1442+101144250.48±.01 +101111.9 ± .2 QSO 18.4 3.53
1511+23 151128.2 ± - +234944. ± EF - .41
2352+49 235237.79±.01 +493326.8 ± .1 GAL 19.0 0.237

Frequency 0742+10 1151-34 1245-19 1328+25 1345+12 1442+10 1511+23 2352+49
960 3.40 7.44 6.78 8.90 6.01 2.50 1.96 2.87
1420 4.00 6.09 5.66 7.07 5.28 2.27 1.51 2.72
2300 4.25 4.59 4.29 5.24 4.29 1.88 1.12 2.35
3650 4.01 3.40 3.14 3.88 3.38 1.47 0.86 1.91
3900 3.95 3.25 2.99 3.71 3.26 1.41 0.82 1.84
4850 3.69 2.79 - 3.20 2.87 1.23 0.73 1.63
7700 3.02 1.98 1.76 2.33 2.16 0.90 0.58 1.21
11200 2.44 1.49 1.28 1.79 - 0.67 0.48 0.92
21700 1.53 0.87 - 1.11 - - - 0.54

return

We recommend to see database of 26-m radio telescope of Michigan University, which includes weekly measurement of flux densities of ~200 bright radio sources at three frequencies: 4.8, 8.0 and 14.5 GHz, among of these sources there are slowly variable point sources. database UMRAO .

19. What and how the observator must know and do

  1. Prepare list of observed sources. Take to account current limitations on time interval between observations. It will add from 2-3 minutes of source drift scans plus 2 x 45s of noise signals plus time of moving of antenna with velocity 5^o/min. In general 60-80 sources could be observed in one day.
  2. 4-5 calibrators must be include in observation set.
  3. Prepere list of source in PLATEX format before set, in order to import this list in task-packet of observations at ref1.ratan.sao.ru.
  4. Use LINUX/X-Window or UNIX interfaces.
  5. Ask radists or skillful observers about details of observations.
  6. Observer must works as user 'obs'. But you could ask include you as named user at server ns.ratan.sao.ru for usual network usage.
  7. Use fgr program to control of recording of observations, which reserve during 2-3 months in directory ratan.sao.ru/PUB/archive/ref1/.
  8. If you use Internet and are user of RATAN server, you could use ftp service to get records after observing set. Also you could use diskettes or DAT-tapes.
  9. Do not suspend publications of results. The two numbers of Bulletene of SAO are published in year. We use English, Latex and new styles of SAO sao1.sty and sao2.sty .
  10. Often look at other WWW-documents of SAO, edited continously now.
    RATAN-600
    www.sao.ru .
  11. Here References of observations, techniques, telescope design and so on.
  12. List 'Who is who' of RATAN stuff.
satr@sao.ru () LabRAO SAO ver. 0.3e 27/11/2006
return Return to the begining flat_mirror flat_mirror center of RATAN-600 feed-cabine N1 for continuum observations feed-cabine N2 for spectral observations feed-cabine N3 for solar observations feed-cabine N6 for whole circle observations feed-cabine #5 This is Northern Sector This is Western sector this is Eastern sector This is South sector This is center numbers of main sectors this is azimuth of antenna