> Begin forwarded message:
> From: "Sander Weinreb" <swein...@caltech.edu>
> Subject: RE: FW: Educational 6m Radio Telescope at Caltech
> Date: September 2, 2015 at 3:55:04 PM PDT
> To: "'heiles'" <hei...@astro.berkeley.edu>
> Cc: "'DAVID DEBOER'" <ddeb...@berkeley.edu>, "'Alan Rogers'" 
> <arog...@haystack.mit.edu>, "'Han'" <st...@kasi.re.kr>, "'Steve Smith'" 
> <ste...@caltech.edu>, "'Monroe Ryan M'" <ryan.m.mon...@jpl.nasa.gov>, "'Gregg 
> Hallinan'" <g...@astro.caltech.edu>, "'Andrew Janzen'" <ajan...@caltech.edu>, 
> "'Ahmed Akgiray'" <ahmed.akgi...@ozyegin.edu.tr>, <asoli...@caltech.edu>, 
> "'Hamdi Mani'" <hamdi.m...@gmail.com>, "'Joe Bardin'" <jcbar...@gmail.com>, 
> "'glenn.caltech'" <glenn.calt...@gmail.com>, "'GLENN WEINREB'" 
> <gwein...@gwinst.com>, "'Anthony Readhead'" <a...@astro.caltech.edu>, "'Shri 
> Kulkarni'" <s...@astro.caltech.edu>
> Carl,
> Thanks,  60 J. with our 6m would give around 0.4K antenna temperature which
> would  be barely detectable with 10KHz resolution, 100K Tsys, and 100 sec
> integration.  It needs tens of minutes integration.  What is the line width?
> Sandy
> -----Original Message-----
> From: Carl E. HEILES [mailto:hei...@berkeley.edu] On Behalf Of heiles
> Sent: Wednesday, September 02, 2015 12:20 PM
> To: Sander Weinreb <swein...@caltech.edu>
> Cc: DAVID DEBOER <ddeb...@berkeley.edu>; Alan Rogers
> <arog...@haystack.mit.edu>; Han <st...@kasi.re.kr>; Steve Smith
> <ste...@caltech.edu>; Monroe Ryan M <ryan.m.mon...@jpl.nasa.gov>; Gregg
> Hallinan <g...@astro.caltech.edu>; Andrew Janzen <ajan...@caltech.edu>; Ahmed
> Akgiray <ahmed.akgi...@ozyegin.edu.tr>; asoli...@caltech.edu; Hamdi Mani
> <hamdi.m...@gmail.com>; Joe Bardin <jcbar...@gmail.com>; glenn.caltech
> <glenn.calt...@gmail.com>; GLENN WEINREB <gwein...@gwinst.com>; Anthony
> Readhead <a...@astro.caltech.edu>; Shri Kulkarni <s...@astro.caltech.edu>
> Subject: RE: FW: Educational 6m Radio Telescope at Caltech
> OH masers...
> hi sandy...
> W49 is not the strongest OH maser. a few of the OH/IR star masers are
> stronger. (less highly polarized, though...). In particular:
>       name              ra             dec             gb            Slo
> Shi
>   0  01037+1219       1.0633333       12.331111      -50.107110
> 60270.4      60315.6
>  27  19192+0922       19.320306       9.3686111      -2.3068318
> 16999.9      40373.0
> where Slo and Shi are gthe flux densities, in mJy, for the low- and
> high-velocity peaks.
> --c
> On Tue, 18 Aug 2015, Sander Weinreb wrote:
>> Carl,
>> Thanks very much!  I looked at the attachments and the  four  
>> experiments including the write-ups  are  an excellent  introduction 
>> to  radio astronomy.
>> A question about OH.  You mention <1K antenna temperature on the
> strongest?
>> maser source, W49.  Is  this  with the 4.5m telescope or with  an older,
>> smaller telescope?   I assume we would need narrow bandwidth, probably 5
>> kHz, and with  a 100K Tsys it will take many minutes of integration to see
>> the signal.   We  also have RFI around 1667 and it will be a challenge to
>> get the filtering and dynamic range.  On the other  hand, the 
>> polarization and multiple lines,  make this  a very instructive venture.
>> I think we have had talks at URSI about educational radio telescopes 
>> but maybe should devote a session  to this at the 2017 meeting.
>> Sandy
>> -----Original Message-----
>> From: Carl E. HEILES [mailto:hei...@berkeley.edu] On Behalf Of heiles
>> Sent: Tuesday, August 18, 2015 4:08 PM
>> To: Sander Weinreb <swein...@caltech.edu>
>> Cc: heiles <hei...@astro.berkeley.edu>; 'DAVID DEBOER'
>> <ddeb...@berkeley.edu>; 'Alan Rogers' <arog...@haystack.mit.edu>; 'Han'
>> <st...@kasi.re.kr>; 'Steve Smith' <ste...@caltech.edu>; 'Monroe Ryan M'
>> <ryan.m.mon...@jpl.nasa.gov>; 'Gregg Hallinan' <g...@astro.caltech.edu>; 
>> 'Andrew Janzen' <ajan...@caltech.edu>; 'Ahmed Akgiray'
>> <ahmed.akgi...@ozyegin.edu.tr>; asoli...@caltech.edu; 'Hamdi Mani'
>> <hamdi.m...@gmail.com>; 'Joe Bardin' <jcbar...@gmail.com>; 'glenn.caltech'
>> <glenn.calt...@gmail.com>; 'GLENN WEINREB' <gwein...@gwinst.com>; 
>> 'Anthony Readhead' <a...@astro.caltech.edu>; 'Shri Kulkarni' 
>> <s...@astro.caltech.edu>
>> Subject: Re: FW: Educational 6m Radio Telescope at Caltech
>> hi sandy...
>> in our undergrad radio astro lab, we currently do four major 
>> experiments, the writeups for which are attached.
>> the first lab is devoted to bench experiments and learning about 
>> digital sampling. the lab in in two halves, and in fact we treat it as 
>> two separate labs. the first half uses test equipment; the second uses 
>> a horn on the roof, baseband complex sampling with the students 
>> writing their own software to get the power spectrum fromthe time 
>> series. i regard this first lab, which covers the basics of sampling 
>> and Fourier tranforms, as absolutely crucial for anybody who intends 
>> to pursue a technical career, and also everything that follows in the lab
> course.
>> the second lab uses our 12 GHz interferometer (freq chosen so that we 
>> can look at the strong methonal masers--which we haven't gotten to yet).
>> baseline is about 12 m. students do vlbi fringe fitting to determine 
>> accurate declinations of sources like Ori A (well, more accurately, 
>> the combination (baseline times cos delta). also look at fringe 
>> amplitude modulation to determine angular diameters of the sun and the
> moon.
>> the third lab uses our 4.5m dish located about a half hour away to map 
>> HI 21-cm line, look at OH, and look at pulsars. Haven't done OH 
>> successfully yet because of equipment problems, but hope to do so this 
>> coming year, and include polarization. hope to get to pulsars this 
>> coming year, but that requires some programming for our FPGA 
>> spectrometer and might not happen this year.
>> generally, course philosophy is that students must write their own
> software.
>> we use IDL. these days, Python would be more approppriate, but at my 
>> age I'm not going to learn yet another language. anyway, the 
>> programming experience gained helps the students a lot in REU research 
>> programs and getting a flavor of instrumentation for later career use.
>> if you desire, you can find some more info (handouts, writeups, etc) 
>> on my web page astro.berkeley.edu/~heiles/
>> it strikes me that if you can't do OH simply because of resolution of 
>> your spectrometer, then this is an excellent project for them to do 
>> direct voltage sampling on and they could do their own FT power 
>> spectra with arbitrary resolution. this would be very instructive.
>> bandwidths can be small so you can keep up with the data rate and disk 
>> files don't need to get too big. many OH masers are highly polaarized, 
>> so a good excuse for them to learn polarization basics. W49 is a 
>> particulary good example. Also there are very strong OH masers 
>> associated with IR stars, also polarized.
>> our telescopes are pointed now by commercial motor controllers, thanks 
>> to dave deboer. doing this well (or even at all) is difficult. i 
>> suspect alan has a simpler and cheaper alernative. also, our 
>> telescopes are home grown; the hardest part is the pointing hardware and
> software...
>> good luck and have fun! there are some other similar labs...i know UW 
>> at madison has one. we ought to convene a get-together so we can 
>> exchange ideas...
>> --c
>> On Sun, 16 Aug 2015, Sander Weinreb wrote:
>>> (Corrected email address for Heiles)
>>> From: Sander Weinreb [mailto:swein...@caltech.edu]
>>> Sent: Sunday, August 16, 2015 10:31 PM
>>> To: carl heiles (hei...@vermi.berkeley.edu) 
>>> <hei...@vermi.berkeley.edu>; Alan Rogers (arog...@haystack.mit.edu) 
>>> <arog...@haystack.mit.edu>
>>> Cc: Dave Deboer (ddeb...@berkeley.edu) <ddeb...@berkeley.edu>; 'Han'
>>> <st...@kasi.re.kr>; Steve Smith (ste...@caltech.edu) 
>>> <ste...@caltech.edu>; Monroe, Ryan M (382F) 
>>> <ryan.m.mon...@jpl.nasa.gov>
>>> Subject: Educational 6m Radio Telescope at Caltech
>>> Carl and Alan,
>>> I need some advice from old salts about how to demonstrate radio 
>>> astronomy observing techniques to new graduate students.
>>> We are paying some attention to the  6m  telescope on the roof of the 
>>> EE building at  Caltech  and are trying to make it into  a good 
>>> teaching instrument.  The front-end covers 1.3 to 1.7 GHz with about 
>>> 100K Tsys on two linear  polarizations and we recently installed a 
>>> Roach 1 spectrometer with two 500 MHz bandwidth channels  and 60 kHz 
>>> resolution. There is much RFI and a lesson we want to teach is how to 
>>> work
>> around it.
>>> Our weakest link is the software to integrate telescope pointing with 
>>> receiver output.  We are working on developing a convenient system 
>>> but I wonder if it already exists on other  small telescopes.  Do you 
>>> have any suggestions for integrated telescope and  data taking 
>>> control system we should look  at?
>>> A second  topic  is  what to observe with the  telescope as 
>>> educational demonstrations.    We can certainly map galactic hydrogen 
>>> and  look at  the stronger continuum sources.  The spectrometer can 
>>> cross correlate the two linear polarizations and we could get into 
>>> polarization measurements. Do you have suggestion  for observations?
>>> I would like to observe OH  (again, since I have not observed it or 
>>> followed what has  been done since 1963 !).   Where is a good summary 
>>> of the observations?   I think  our 60 KHz resolution is too  broad 
>>> and we will need to improve it by a factor of 10 or more.
>>> Sandy

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