Hi, in my QTH sun was covered 68% and sun noise dropped 3.5dB on 23cm. During total eclipse Aug.11th 1999 sun noise had dropped 10dB on 23cm and 6dB on 70cm. 73 - - - Hannes - - - (OE5JFL) ----- Original Message ----- From: peter blair To: ok1dfc(a)seznam.cz Cc: Sent: Friday, March 20, 2015 11:13 AM Subject: Re: [Moon-Net] Partial eclipse tomorrow Thanks, Is that 23cm Zdenek? From: "ok1dfc(a)seznam.cz" <ok1dfc(a)seznam.cz> To: peter blair <g3ltf(a)btinternet.com> Cc: "moon-net(a)mailman.pe1itr.com" <moon-net(a)mailman.pe1itr.com>om>; "moon(a)moonbounce.info" <moon(a)moonbounce.info> Sent: Friday, 20 March 2015, 10:07 Subject: Re: [Moon-Net] Partial eclipse tomorrow During maximum of eclipse today Sun noise drop down 6dB, compare with 04/01/2011 eclipse http://www.ok1dfc.com/eme/mereni/eclipse_04_01_11.htm when we had 80% and than noise drop down -6,5dB -- Zdenek - OK1DFC www.ok1dfc.com QRV 144 - 3400 MHz EME - QRO and 10m DISH WAC 432 - 1296 - 2320 MHz DXCC 432 MHz ---------- Původní zpráva ---------- Od: peter blair <g3ltf(a)btinternet.com> Komu: moon-net(a)mailman.pe1itr.com <moon-net(a)mailman.pe1itr.com>om>, moon(a)moonbounce.info <moon(a)moonbounce.info> Datum: 19. 3. 2015 11:26:54 Předmět: [Moon-Net] Partial eclipse tomorrow If at all possible try and make an accurate measurement of sun noise during the eclipse period on what ever band you can. Ideally we are looking for the ratio between normal level (measured on the same day) and the minimum sun noise occurring at the time of maximum shadowing. You can get the timing for your exact location from this link. http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2015Mar20Tgoogle.html We believe that we can possibly accumulate some interesting measurements on a non-quiet sun which might indicate how much noise comes from the corona compared to the disc. This influences what value is used for the solar diameter when making beamwidth measurements for example. GL 73 Peter G3LTF _______________________________________________ Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html ------------------------------------------------------------------------------ _______________________________________________ Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html

Hi Peter, Would sincerely have liked to measure with my dish, but I enjoyed taking my students to the roof of Leiden astronomical center, see here: http://www.astronomie.nl/#!/actueel/agenda/_detail/gli/avondje-sterrenwacht… We had a wonderful morning and saw the partial eclipse in spite of some clouds ;) VY 73, Dick PA2DW

13cm here measured 5dB drop but this is a first look, need to look more at the recorded data. Im now measureing 9cm on the last 30 mins 73 Peter G3LTF ________________________________ From: "ok1dfc(a)seznam.cz" <ok1dfc(a)seznam.cz> To: peter blair <g3ltf(a)btinternet.com> Cc: "moon-net(a)mailman.pe1itr.com" <moon-net(a)mailman.pe1itr.com>om>; "moon(a)moonbounce.info" <moon(a)moonbounce.info> Sent: Friday, 20 March 2015, 10:07 Subject: Re: [Moon-Net] Partial eclipse tomorrow During maximum of eclipse today Sun noise drop down 6dB, compare with 04/01/2011 eclipse http://www.ok1dfc.com/eme/mereni/eclipse_04_01_11.htm when we had 80% and than noise drop down -6,5dB -- Zdenek - OK1DFC www.ok1dfc.com QRV 144 - 3400 MHz EME - QRO and 10m DISH WAC 432 - 1296 - 2320 MHz DXCC 432 MHz ---------- Původní zpráva ---------- Od: peter blair <g3ltf(a)btinternet.com> Komu: moon-net(a)mailman.pe1itr.com <moon-net(a)mailman.pe1itr.com>om>, moon(a)moonbounce.info <moon(a)moonbounce.info> Datum: 19. 3. 2015 11:26:54 Předmět: [Moon-Net] Partial eclipse tomorrow If at all possible try and make an accurate measurement of sun noise during the eclipse period on what ever band you can. Ideally we are looking for the ratio between normal level (measured on the same day) and the minimum sun noise occurring at the time of maximum shadowing. You can get the timing for your exact location from this link. http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2015Mar20Tgoogle.html

 Thankyou JJ, much appreciated. I think  the sun is very active at present ( we had excellent Au as you know) and so possibly / probably the corona diameter is larger. First thing is to collate all the results. vy 73 Peter ________________________________ From: JJ Mx &lt;jjm_f1ehn(a)wanadoo.fr&gt; To: 'peter blair' &lt;g3ltf(a)btinternet.com&gt;om>; moon(a)moonbounce.info; moon-net(a)mailman.pe1itr.com Cc: moon-net(a)list-serv.davidv.net Sent: Friday, 20 March 2015, 18:13 Subject: RE: [Moon-Net] Partial eclipse tomorrow Hello Peter and all, These compilations of measurements will be very interesting. My previous eclipse  I did measurement on 3 cm in 1996. The signal dropped in a near ratio as the optical eclipse. Today I did the measurement @1.4 GHz (outside H1 line) and I noted the signal dropped less than the optical eclipse (around 4 dB (~40%) for 78% in optic – near PARIS). Moreover the radio eclipse started before the optical eclipse and finished later than the forecast. The sun seemed to be bigger at this frequency (probably coming from its hot chromosphere – I am not an expert and I have to find more info). It is the 1st time I used my 21cm station for a sun eclipse. I will send you ASAP the data of the complete eclipse. 73. JJ F1EHN     De :moon-net-bounces@mailman.pe1itr.com [mailto:moon-net-bounces@mailman.pe1itr.com] De la part de peter blair Envoyé : vendredi 20 mars 2015 11:19 À : ok1dfc(a)seznam.cz Cc : moon(a)moonbounce.info; moon-net(a)mailman.pe1itr.com Objet : Re: [Moon-Net] Partial eclipse tomorrow   13cm here measured 5dB drop but this is a first look, need to look more at the recorded data. Im now measureing 9cm on the last 30 mins 73 Peter G3LTF From:"ok1dfc@seznam.cz" &lt;ok1dfc(a)seznam.cz&gt; To: peter blair &lt;g3ltf(a)btinternet.com&gt; Cc: &quot;moon-net(a)mailman.pe1itr.com&quot; &lt;moon-net(a)mailman.pe1itr.com&gt;om>; &quot;moon(a)moonbounce.info&quot; &lt;moon(a)moonbounce.info&gt; Sent: Friday, 20 March 2015, 10:07 Subject: Re: [Moon-Net] Partial eclipse tomorrow   During maximum of eclipse today Sun noise drop down 6dB, compare with 04/01/2011 eclipse http://www.ok1dfc.com/eme/mereni/eclipse_04_01_11.htm when we had 80% and than noise drop down -6,5dB -- Zdenek - OK1DFC www.ok1dfc.com QRV 144 - 3400 MHz EME - QRO and 10m DISH WAC 432 - 1296 - 2320 MHz DXCC 432 MHz ---------- Původní zpráva ---------- Od: peter blair &lt;g3ltf(a)btinternet.com&gt; Komu: moon-net@mailman.pe1itr.com<moon-net@mailman.pe1itr.com>, moon@moonbounce.info<moon@moonbounce.info> Datum: 19. 3. 2015 11:26:54 Předmět: [Moon-Net] Partial eclipse tomorrow   If at all possible try and make an accurate measurement of sun noise during the eclipse period on what ever band you can. Ideally we are looking for the ratio between normal level (measured on the same day) and the minimum sun noise occurring at the time of maximum shadowing. You can get the timing for your exact location from this link. http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2015Mar20Tgoogle.html

Hi JJ, Re: The differences you observed RF vs optical [both depth and width of null]: What was the beamwidth of your dish? I would think that the wider RF beamwidth could explain both observations, depending upon just how wide it was compared to the optical beamwidth, which would of course be quite narrow. One would need to know the beamwidth and the geometric details of the occultation to do the calculation. 73, Roger Rehr W3SZ On 3/20/2015 2:13 PM, JJ Mx wrote:

Hi Roger, The beamwidth of my dish is 4.4° (3.3m @ 1.4 GHz) Find below the geometry of the sun/moon eclipse for my antenna location. I did the comparison with the optical eclipse time for the beginning and end of contact between moon and sun. Maximum was around 9:22 UTC. If you need more details, please ask me. Best regards and 73. JJ F1EHN De : moon-net-bounces(a)mailman.pe1itr.com [mailto:moon-net-bounces@mailman.pe1itr.com] De la part de Roger Rehr W3SZ Envoyé : vendredi 20 mars 2015 22:00 À : moon-net(a)mailman.pe1itr.com Objet : Re: [Moon-Net] Partial eclipse tomorrow Hi JJ, Re: The differences you observed RF vs optical [both depth and width of null]: What was the beamwidth of your dish? I would think that the wider RF beamwidth could explain both observations, depending upon just how wide it was compared to the optical beamwidth, which would of course be quite narrow. One would need to know the beamwidth and the geometric details of the occultation to do the calculation. 73, Roger Rehr W3SZ On 3/20/2015 2:13 PM, JJ Mx wrote: Moreover the radio eclipse started before the optical eclipse and finished later than the forecast. The sun seemed to be bigger at this frequency (probably coming from its hot chromosphere – I am not an expert and I have to find more info).

Roger and all, I was looking into this subject when working with Doug on his EMECalc software and the issue of beam filling factor when using narrow beamwidths and non-point sources came up. I came accross an interesting book chapter titled 4.1.1.6 Radio Emission of the Quiet Sun by Arnold.O.Benz . I have it as a pdf and Im not sure now where I found it, it was a free download. Figure 5 which you can see here http://www.authormapper.com/search.aspx?val=publication%3ASolar+System&…ld+O. shows the effect of radiation from the halo or corona quite clearly. Many of the measurements were made during eclipse. At 3cm it looks like the solar radius is about 5% larger and at 23cm 15% larger. This is why I thought it would be interesting to try and get some multi frquency data when the sun was not quiet. Obviously our data quality will be mixed but it will be interesting to see what can be extracted from the results. 73 Peter G3LTF From: Roger Rehr W3SZ Sent: Saturday, March 21, 2015 2:21 AM To: JJ Mx ; 73w3sz(a)gmail.com ; moon-net(a)mailman.pe1itr.com Subject: Re: [Moon-Net] Partial eclipse tomorrow Hi JJ and Ed et al, I need to correct at least part of my statement about the effects of the antenna beamwidth on the depth and width of the notch in sun noise during an eclipse. My thinking was faulty. Detector beamwidth [antenna or eye] will affect the apparent diameter of an object that is captured in transit mode, either by allowing the object to transit across the beamwidth of the detector, or by sweeping the detector's beamwidth across the object; just consider the two extremes: A tiny object will be detected by a sufficiently sensitive detector when it enters the beamwidth at one edge of the detector's field of view and continue to be detected until it leaves the beamwidth at the other edge. So its apparent angular diameter will be on the order of the beamwidth of the detector, as long as it is well centered in the detector's field of view. On the other hand, the angular diameter of an object much larger than the detector beamwidth can be accurately measured as long as it is well centered in the detector's field of view. But for the eclipse experiments, the detector would be locked onto the sun, with the sun centered well within its beamwidth. So the larger beamwidth of the RF array vs the optical array does not directly cause a widening of the notch nor a decrease in the depth of the notch for the RF experiment vs the optical experiment by way of the mechanism described above. What the larger beamwidth does do is to contribute to a reduction in the signal to noise ratio of the RF system as compared to a system where the entire beamwidth is filled by the sun [as it would be in an optical system with appropriately chosen region of interest]. For this case we have: Diameter of sun and moon 30 minutes, or 0.5 degree. Optical resolution of the human eye 1 minute, or 1/60 degree. So each pixel will be much smaller than the sun. Optical resolution of a telescope is even better, ~ wavelength/Objective diameter. So again each pixel will be much smaller than the sun. Beamwidth of the antenna is 4.4 degrees. So each pixel is much larger than the sun [and yes, there is only one pixel]. The sun fills only (0.5/4.4)**2 or 1.2% of the pixel. So with the human eye or telescope the sun can be very accurately represented and a region of interest accurately drawn. Relative detector sensitivity will be 100%. With a 4.4 degree beamwidth dish the relative detector sensitivity based solely on this geometric argument will be 1.2%. For this reason and others the RF system will have poorer signal to noise ratio than the optical system. I believe any effect of the larger beamwidth of the antenna vs the optical systems will be due to the poorer statistics of the RF system, due to the reduced signal to noise ratio of the RF system vs the optical system. This would be expected to produce a shallower null, but instead of broadening the null as I first stated, this statistical effect would narrow the null. This latter effect would because with poorer signal to noise ratio, the small difference in signal level caused by a very slight occultation of the sun at the very beginning and end of the eclipse would be hidden due to the poorer signal to noise ratio of the RF system. JJ had mentioned the possibility of an RF halo [my words] affecting the results. I had also done some thinking along those lines, but then I remembered that when I use moon noise to keep my 0.79 degree beamwidth dish peaked on the moon on 10 GHz, the moon seems like a tiny object and it does not seem to subtend a greater angle than my beamwidth. That observation suggests that there is not a significant RF halo, at least at 10 GHz. I checked on the net, and found an NRAO page that says that at 4.6 GHz the edge of the RF limb of the sun is only about 20,000 km above the optical edge of the sun; a tiny difference given that the diameter of the sun is 1,392,000 km. Given these results on 10 GHz and 1.2 GHz, I suspect that on 1-1.5 GHz the result is similar. No halo sufficiently large or intense to affect the results directly. On an image, the RF limb of the sun looks like the thickness of an eggshell above the optical limb. There is a nice [and brief] discussion of this below a picture showing the RF limb superimposed on the optical limb at http://www.cv.nrao.edu/course/astr534/Tour.html Scroll down to the second image, the one showing a blue green disk that is the sun and read the caption for more info on this. The rest of the page is very interesting too, as you might guess since it is titled "A Tour of the Radio Universe". Hope the above is of interest to some folks out there! Maybe our radioastronomers in the group will tell us what is really going on :) 73, Roger Rehr W3SZ On 3/20/2015 6:55 PM, JJ Mx wrote: Hi Roger, The beamwidth of my dish is 4.4° (3.3m @ 1.4 GHz) Find below the geometry of the sun/moon eclipse for my antenna location. I did the comparison with the optical eclipse time for the beginning and end of contact between moon and sun. Maximum was around 9:22 UTC. De : moon-net-bounces(a)mailman.pe1itr.com [mailto:moon-net-bounces@mailman.pe1itr.com] De la part de Roger Rehr W3SZ Envoyé : vendredi 20 mars 2015 22:00 À : moon-net(a)mailman.pe1itr.com Objet : Re: [Moon-Net] Partial eclipse tomorrow Hi JJ, Re: The differences you observed RF vs optical [both depth and width of null]: What was the beamwidth of your dish? I would think that the wider RF beamwidth could explain both observations, depending upon just how wide it was compared to the optical beamwidth, which would of course be quite narrow. One would need to know the beamwidth and the geometric details of the occultation to do the calculation. 73, Roger Rehr W3SZ On 3/20/2015 2:13 PM, JJ Mx wrote: Moreover the radio eclipse started before the optical eclipse and finished later than the forecast. The sun seemed to be bigger at this frequency (probably coming from its hot chromosphere – I am not an expert and I have to find more info). -------------------------------------------------------------------------------- _______________________________________________ Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html

Roger, Comments inserted below: At 06:21 PM 3/20/2015, Roger Rehr W3SZ wrote: If tracked exactly thru the center of the object the result will be the same curve. Drift curves are favored because antenna mechanical tracking variations are eliminated (antenna fixed in position)(assumed no wind effects). Yes. Usual example is the infinitely small object: point source. If angular size is much larger than that of the antenna. Typically the reality is somewhere between these two extremes. e.g. the antenna is tracking the center of the sun. Correct. Yes. You see this with more significance when tracking the moon. If antenna bw is much larger than apparent angular size of the Moon antenna noise is the sum of the moon thermal noise and background sky noise. The lunar noise "bump" is smaller in dB. That is the optical size of the sun. The radio sun is larger in apparent angular size (per Flagg about 2-degrees). Of course this depends on observing wavelength. You have assumed brilliance is the same at radio as optical wavelengths - not true. You cannot make this argument as the sun's output is different at optical vs RF. In fact the angular size of the earth's shadow is what determines the duration of the eclipse and amount of variation in brightness is determined by the amount of blockage of the earth's disc over the apparent size of the sun. At visible light the earth almost matches the sun in apparent size; at mw frequencies the sun is larger than the earth in apparent size. Thus the effect on radio brightness will likely be less deep a drop. The Moon is a rock. It emits thermal noise from its surface therefore visual size and radio size are nearly equal. Truer at mw wavelengths where one can discern a radio disc; at 2m the Moon is a blob in the sky. The Moon has no corona emission. The sun does. You have seen photos of the sun corona extending farther out from the optical disc. OK, that is contrary to what I have read. The apparent radio sun varies in brilliance and size depending on wavelength of observation. I'll see if I can find the paper I cited earlier. Maybe my memory is faulty. 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubususa(a)gmail.com

Hi Peter and other researchers, It's so interesting to see what happens during the eclipse. The radio-size of the sun would be a nice point of view! A few years back in JA, total eclipse occured and some guys measured and recorded the data on microwave bands. Incidentally I have to move this week and the next, and no time to maintain my shack for a while. I will live closer to my shack, 5-10 minutes drive, from April. This is the end of my great journey every time ca. 600km back and force for the radio/EME. Thanks a lot!! Mike JH1KRC ---- peter blair &lt;g3ltf(a)btinternet.com&gt; wrote: 73 Peter G3LTF ________________________________ From: &quot;ok1dfc(a)seznam.cz&quot; &lt;ok1dfc(a)seznam.cz&gt; To: peter blair &lt;g3ltf(a)btinternet.com&gt; Cc: &quot;moon-net(a)mailman.pe1itr.com&quot; &lt;moon-net(a)mailman.pe1itr.com&gt;om>; &quot;moon(a)moonbounce.info&quot; &lt;moon(a)moonbounce.info&gt; Sent: Friday, 20 March 2015, 10:07 Subject: Re: [Moon-Net] Partial eclipse tomorrow During maximum of eclipse today Sun noise drop down?6dB, compare?with 04/01/2011 eclipse http://www.ok1dfc.com/eme/mereni/eclipse_04_01_11.htm?when we had 80% and than noise drop down -6,5dB -- Zdenek - OK1DFC www.ok1dfc.com QRV 144 - 3400 MHz EME - QRO and 10m DISH WAC 432 - 1296 - 2320 MHz DXCC 432 MHz ---------- P?vodn? zpr?va ---------- Od: peter blair &lt;g3ltf(a)btinternet.com&gt; Komu: moon-net(a)mailman.pe1itr.com &lt;moon-net(a)mailman.pe1itr.com&gt;om>, moon(a)moonbounce.info &lt;moon(a)moonbounce.info&gt; Datum: 19. 3. 2015 11:26:54 P?edm?t: [Moon-Net] Partial eclipse tomorrow If at all possible try and make an accurate measurement of sun noise during the eclipse period on what ever band you can. Ideally we are looking for the ratio between normal level (measured?on the same day) and the minimum sun noise occurring at the time of maximum shadowing. You can get the timing for your exact location from this link. http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2015Mar20Tgoogle.html

That's brilliant Willi, thanks so much. We have a lot of data to look at  but already measurements on 6 frequencies. 73 Peter ________________________________ From: Willi Bauer &lt;wbauer(a)pt.lu&gt; To: 'peter blair' &lt;g3ltf(a)btinternet.com&gt;om>; moon-net(a)mailman.pe1itr.com; moon(a)moonbounce.info Sent: Friday, 20 March 2015, 11:24 Subject: RE: [Moon-Net] Partial eclipse tomorrow Hi Peter   Please find here the measurements of the partial eclipse for 3,4 GHz and 10 GHz.   On 3,4 GHz I do measured : normal the sun 15,7db at 08:30 the min at 09:25 12,2db at 09:46 12,7db and at the end again 15,7db   On 10GHz more detailed: 08:35   16,2db 09:40   15,0db 09:15   14,5db 09:20   13,5db 09:28   12,5db min 09:45   13,5db 09:52   14,0db 09:57   14,3db 10:01   14,8db 10:04   15,0db 10:10   15,5db 10:30   16,1db   That is the result Peter.   73 cu Willi LX1DB   From:moon-net-bounces@mailman.pe1itr.com [mailto:moon-net-bounces@mailman.pe1itr.com] On Behalf Of peter blair Sent: Donneschdeg 19 Mäerz 2015 11:16 To: moon-net(a)mailman.pe1itr.com; moon(a)moonbounce.info Subject: [Moon-Net] Partial eclipse tomorrow   If at all possible try and make an accurate measurement of sun noise during the eclipse period on what ever band you can. Ideally we are looking for the ratio between normal level (measured on the same day) and the minimum sun noise occurring at the time of maximum shadowing. You can get the timing for your exact location from this link. http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2015Mar20Tgoogle.html We believe that we can possibly accumulate some interesting measurements on a non-quiet sun which might indicate how much noise comes from the corona compared to the disc. This influences what value is used for the solar diameter when making beamwidth measurements for example.  GL 73 Peter G3LTF

A plot of my measurements at 2320. The "bars" are an artefact of my dish tracking On 20 March 2015 at 11:24, Willi Bauer &lt;wbauer(a)pt.lu&gt; wrote: