> 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 >>> >>> >>> >> >> >
