Here are minutes of our meeting on Thursday -- please just reply with (or let me know) any corrections -- thanks!:
Attendees: Arnold Gaertner (NRC), Karun Thanjavur (UVic), Houman Hakima & Cordell Grant (UTIAS-SFL), and Sri Krishna Uppaluri (JHU). Apologies: Yorke Brown (Dartmouth)
Yorke had accidentally scheduled another overlapping meeting this week -- he'll be back for our next meeting of course though -- and reports that he and Cynthia continue to prepare payloads for our upcoming flight campaign this spring. Cynthia has finished the source mounting components and is working on foam configuration for the payloads.
This Wednesday evening (Feb. 11), undergrad Nic Loewen, as well as Karun and I, did some laboratory and then rooftop tests of 50 kHz readout of laser atmospheric scintillation over a short (~75 m) path length, to test the ability to see fluctuations at 1 kHz and above. Data, as well as some plots, can be found at https://particle.phys.uvic.ca/~jalbert/PhotodiodeLaserTests/ for the rooftop tests, and the subdirectory https://particle.phys.uvic.ca/~jalbert/PhotodiodeLaserTests/PhotosensorTests/ for the laboratory tests that Nic did prior to our rooftop tests. The data itself is in the .cmbl files, and there are some plots in .JPG files in those directories. The laboratory tests show that the readout system that we used is clearly capable of accurately recording 1 kHz (and below) light source fluctuations, however light source fluctuations at frequencies significantly above 1 kHz appear to have a lot of noise when read out using this system (even though at least in principle the readout samples at 50 kHz). The atmospheric scintillation over the 75 m path appears to have a lot of power at around ~200 Hz frequencies (and not much between ~400 Hz to 2 kHz), but it is hard (or impossible) to tell with this system whether there is any significant power at above 2 kHz, since that readout doesn't appear to be very accurate above that frequency. We will try using another readout system (which is somewhat more complex and unwieldy to use, but should be very accurate at high frequencies). Then, when we're happy with that, we'll try another 10 km path length test between Mt. Tolmie and Observatory Hill like we did on Jan. 15 (https://particle.phys.uvic.ca/~jalbert/LaserTolmieObservatoryHillData_25jan15/), but with high-rate photodiode readout as well.
Houman has completed his very beautiful solid model design for the nanosat, and has essentially completed writing up the work up in his master's thesis. I've of course seen it and it looks excellent and beautiful to me -- Houman and Cordell will be sending and posting more info and pictures of it soon.
Our JHU colleagues are making very good progress with their return-to-home model aircraft balloon payload. They are continuing to do very useful tests below the 400 ft altitude limit. FAA approval has not been received quite yet for above-400 ft testing; they don't expect to get that in the next 6 weeks, but hopefully very shortly afterwards, and in the meantime they are proceeding with low altitude flights as well as laboratory work of course. They will send a video when they have a nice new one to share.
That's all I remember, please send things that I forgot. Next telecon in 2 weeks, on Thursday, Feb. 26 at 1:30 pm Eastern time.
cheers, thanks all! justin
On Thu, 12 Feb 2015 02:41:02 GMT, Justin Albert wrote:
> Hi! > > Telecon tomorrow (Feb. 12) at our usual time: 1:30 pm Eastern (10:30 am > Pacific, 19.30 European). Discussion items include: planning for > flights, light sources and light source modelling, goniometric and pre- > and post-flight calibration, communications tests, new nanosat bus and > payload solid models from Houman, computing/website, grant applications, > and recap of schedules. A reminder of the CSA project timeline is > attached. > > Here's how to connect: > 1) Open Skype on your computer (note that of course, you should first install Skype, http://www.skype.com , on your machine if you haven't already). > 2) In the "Contacts" menu, add me ( jalbertuvic ) as a contact, if you haven't already. > 3) Just wait for me to Skype-call you at the usual time (1:30 pm Eastern, 10:30 am Pacific). > 4) If there is any trouble, or if you don't get a call for some reason and would like to join, just send me an e-mail (jalbert@uvic.ca). > > Here's the tentative agenda: > I) Flight planning > II) New diffused light source and its modelling, pre- and post-flight calibration, and goniometric calibrations > III) Communications tests (possible backup optical and radio, etc) > IV) New nanosat solid models from Houman and Cordell > V) Computing/website > VI) Grant applications > VII) AOB > > Talk to you all tomorrow, thanks! > justin > > Attachments: > http://projectaltair.org/HyperNews/get/AUX/2012/11/12/18.02-43361-Schedule-20120702_hqp.pdf >