DIY Solar Scintillation Seeing Monitor with FC support

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
RTJoe
Oh, I get it now!
Oh, I get it now!
Posts: 24
Joined: Tue Jun 16, 2015 8:26 am
Location: Germany

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by RTJoe » Wed Nov 23, 2016 10:30 pm

Hello,

plugin version v0.92 is released now.

This version now "officially" supports the SSM from AiryLab in FireCapture. Thanks to user rxdeath for testing:
SSSMonScr_AiryLab.jpg
SSSMonScr_AiryLab.jpg (152.42 KiB) Viewed 3437 times
One main addition is the new chart window with graphical plot of the seeing values. This windows is a FireCapture window, it's no longer necessary to use additional software to display a chart.
SSSMonScr_ChartEN.jpg
SSSMonScr_ChartEN.jpg (89.34 KiB) Viewed 3437 times
The plugin writes the average seeing value during a recording run into the FireCapture log file and optionally can write an additional log file with the seeing value for each captured frame. The format of this log file is CSV, it can be easily processed or imported e.g. into Excel.

A new firmware is also available, providing calculation of an alternative seeing value based on more (and longer) scintillation measures.

Plugin and Firmware are available for download here: http://www.joachim-stehle.de/sssm_eng.html. Please use the latest release version 2.5 of FireCaputue.

Joachim

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Thu Nov 24, 2016 8:08 am

Perfect job Joachim!

I will test it out a soon as I get some decent sunshine. The SSSM monitor with the Nano now seems to function as expected while testing during a short period of sunshine. (But then trees got in the way ...)

Kind regards,
Paul

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Fri Nov 25, 2016 6:32 pm

Hi,

so first real outside testing today.
This is what I got in the SSSM
Measure1.jpg
Measure1.jpg (174.31 KiB) Viewed 3371 times
I had the impression seeing was worse than what the device was reporting. Only could get this poor result. (but of course Quark runs at f/24.5 and that seemed to be to much today)
PP2016-11-25-1019_5-PDB-Ha__SSSM_1.8.jpg
PP2016-11-25-1019_5-PDB-Ha__SSSM_1.8.jpg (24.26 KiB) Viewed 3371 times
little bit later seeing got worse (also through the camera)
This data was collected using the larger number of samples
Measure4.jpg
Measure4.jpg (152.96 KiB) Viewed 3371 times
The plugin works as expected, starting at the right moment, pausing when needed. Now need to figure out what settings work best.

Kind regards,

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Fri Jun 02, 2017 2:48 pm

Any particular updates from anyone who has completed a monitor?

I'm interested in building one just for fun to monitor seeing while I'm at my scope.

I have no experience with boards, circuits, etc, though. May be beyond what I can do without someone helping or a video or something.

Very best,

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Fri Jun 02, 2017 5:32 pm

Hello Marty,

not that difficult to make (i have no experience in electronics either), but you need to be able to do a little bit of soldering on a strip- or veroboard.
What I found the most difficult thing was to mounting the sensor.
Difficult parts to find were the original sensor, so replaced in by the BPW34. That one is tiny and difficult to solder, but beeing cheep, I ordered 4 so i had some spare parts. Also the NP capacitor can be hard to find.

Seems I have thrown away my veroboard design (was just a sketch on paper). Will "clean" my desk a bit, maybe I can find it back.

As for the device, it works very well and is a great help reducing the captures to usefull and much smaller files than before.

Regards,

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Fri Jun 02, 2017 7:26 pm

Hi Paul,

Thanks. I suppose I'd have to start by finding out how to even interpret the schematic on the original PDF to know what any of it means. I actually found all the bits, the boards, the sensor and the amp, so I can get the parts quite inexpensively (though I have no idea what any of the wires, resistors, capacitors, or anything of that stuff is). More just a matter of knowing what I'm doing putting them together and how to load the software and how to have it output to a laptop and produce data to interpret.

I bought two of the sensors (VTP4085H), two of the LMC6484 amps, and an Arduino uno R3 board.

From here, I just need to know if I need to get a solder setup, or if I can get some kind of wires that allow me to use them without soldering so I can see if it works without it being permanent and ruining stuff. Jumper wires? I'm looking at small bread boards and wire kits that are commonly listed with the arduino boards. But I'm not sure of any of it.

I figure one to learn on, one to do right (maybe), once I get everything I need and figure this stuff out. And if it works out, maybe I'll build a few since I can get the parts so easily and inexpensively.

Too bad there's not a simple video tutorial out there to show one of these being built with instruction!

Very best,
Marty
Last edited by MalVeauX on Fri Jun 02, 2017 7:38 pm, edited 1 time in total.

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Fri Jun 02, 2017 7:32 pm

Marty,

give me a few days and I will reconstruct the board layout I made for a strip-board. (not that difficult)

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Fri Jun 02, 2017 7:39 pm

Thanks Paul, appreciate it.

BTW, I edited in some more information prior to this post:

"

I bought two of the sensors (VTP4085H), two of the LMC6484 amps, and an Arduino uno R3 board.

From here, I just need to know if I need to get a solder setup, or if I can get some kind of wires that allow me to use them without soldering so I can see if it works without it being permanent and ruining stuff. Jumper wires? I'm looking at small bread boards and wire kits that are commonly listed with the arduino boards. But I'm not sure of any of it.

"

Example: not sure if I can use this (to avoid soldering at first to at least learn with):

https://www.amazon.com/dp/B004RXKWDQ/re ... UTF8&psc=1

Very best,

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Fri Jun 02, 2017 7:48 pm

Need to check. In theory you could place the components on a breadbord and then connect with wires to the Arduino, but of course theory an practice do not always go hand in hand.

Very best

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Fri Jun 02, 2017 10:49 pm

Hrm,

So just going back and reviewing some material:

Looks like from the program, basically the IR sensor is measuring light intensity and its becoming converted to a voltage value that is monitored. Basically the intensity of the light change over time is being correlated to seeing quality. Does that sound correct?

I've watched some YouTube tutorials on the Arduino boards, basic circuitry, etc. Looked at the software to load the sketches onto the Arduino too. Seems easy enough for the most part. Looks like I can use solderless jumper wires to practice on a breadboard to make sure the circuit works before moving to a permanent build, so that's good.

So now I really just need to learn to read the schematic on the original PDF so that I understand what the symbols mean and how to follow the circuit design because when I compare the schematic in the PDF to the image of the breadboard, I'm not able to follow it very far before losing where the circuit is going. For example in the PDF I read about 5 instances of a resistor (values 220, 47k, 10k, 10k, and 20meg) and I see them on the board, but I guess I'm getting lost on where it translates to the mirror side of the board and back.

So really I don't think I'm able to read the schematic yet.

Looks like the microprocessor is referenced 4 times (U1 through U4) and that there are two capacitors (non polarized) in the schematic? One that's 3.3 micro-ferads and one that is 20 pico-ferads, right?

Also, I probably need to figure out how to connect the photodiode to a cable, like the shielded RCA, so that I can mount that on the scope and run the cable to the board near the computer. That will take soldering I'm sure, so I will have to get into that a bit too. But I don't mind testing it without a cable at first just to ensure its working and to get the voltage correct at that stage (to 1V). I think I'll get a variable resistor to attenuate it to 1V, even though it says 220 ohm resistance, but says to change it to get to 1V).

Very best,

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Sat Jun 03, 2017 9:15 am

Marty,

will send you a private message.

Rgrds,

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Sat Jun 03, 2017 9:23 pm

Hey all,

So I'm trying to make sure I get the right components per the original PDF, just want to make sure I'm reading it correctly and found the correct items if anyone familiar wouldn't mind confirming:

10k Resistor x 2: http://www.mouser.com/ProductDetail/KOA ... YulfaVM%3d

20 Meg Resistor x 1: http://www.mouser.com/ProductDetail/Ohm ... lJaLh0I%3d

47k REsistor x 1: http://www.mouser.com/ProductDetail/KOA ... wvink34%3d

Capacitor 3.3 micro Ferad non-polar x 1: http://www.mouser.com/ProductDetail/Vis ... %252b7o%3d

Capacitor 20 pico Ferard x 1: http://www.mouser.com/ProductDetail/Vis ... W9kYh4o%3d

Very best,

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Sun Jun 04, 2017 1:27 pm

The 3.3 mF capacitor should be of type NP. Could not see that from the spec. Looks like a standard one. (there seems to be a way to use normal capacitators, if you use 2, but then the value will be different, and that is far beyond my knowledge)

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Sun Jun 04, 2017 3:42 pm

Turns out all most all of that above is the wrong stuff. I didn't know the difference between carbon film, metal, etc, none of this is in the schematic so I have no idea what the differences really are, there's so much as it is.

If anyone is familiar with the stuff and can link the items per the original PDF, that would be really helpful.

+++++++++++

Looks like I need 1/4watt, 5% carbon film. I'd have never known! Hah.
I guess the size of the capacitors and all that eluded me as well.
Also, no idea how to know if the potentiometer for the variable resistance would have the ranges needed to achieve something around 220ohm, or whatever it turns out to be to achieve the 1V at the photodiode.

++++++++++++++

Let's see if I can get any of this right:

10k Resistor x 2:
http://www.mouser.com/ProductDetail/KOA ... %2f2Y24%3d

20Meg Resistor x 1:
http://www.mouser.com/ProductDetail/KOA ... XXOMQTs%3d

47k Resistor x 1:
http://www.mouser.com/ProductDetail/Yag ... CvOsHqQ%3d

Is this an appropriate 3.3 uF non-polar capacitor?
https://www.parts-express.com/33uf-100v ... mpaign=pla

Is this an appropriate 20 pF capacitor?
http://www.mouser.com/ProductDetail/Vis ... hgodkEcL8A

No idea how to even select an appropriate variable resistance, or potentiometer. Or if I follow the original schematic, a 220ohm is used, so should be possible to just do that again. But if I extend the sensor off the board with a cable, will that change anything?

Very best,

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Sun Jun 04, 2017 4:41 pm

As variable resistor use one for 2K (that will give all the range from 0 to 2K). When testing you adjust it until you get an input value between 0.6 to 0.9 when the cell is in full sunlight. (even 1K value could be ok)

The capacitor looks ok.

Rgrds,

Paul

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Sun Jun 04, 2017 4:58 pm

Thanks,

Way more complicated even just finding parts that are appropriate than anything it seems!

Very best,

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Thu Jun 08, 2017 1:21 pm

So, I have most of the parts now.

I have:

VTP4085H sensors
LMC6484 I/O OP Amp
Arduino Uno R3 Controller
Breadboard & Jumper Wires

I haven't picked up any resistors, capacitors, etc, yet because I can't seem to find exactly what is needed due to my inexperience and lack of education in this kind of stuff. I at least know the type of basic resistors I need, but I'm not confident with the capacitors, and I'm really not sure of the variable resistor pot to make sure its the right kind and range of values. And then, I still am not confident on how to set it up on the board, but I can at least play with it a little with the jumper wires. I have multiples of everything above in case I torch it.

I've linked some resistors, capacitors and a variable resistor pot above; if someone can help me confirm what I can/cannot use. I'm trying to follow the original PDF design as closely as possible. If I can make it work, I will then look into extending the sensor off the board and onto an audio cable or something to get it onto the telescope. But that's later, if I can get this to work.

?

Very best,

RTJoe
Oh, I get it now!
Oh, I get it now!
Posts: 24
Joined: Tue Jun 16, 2015 8:26 am
Location: Germany

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by RTJoe » Wed Jun 14, 2017 11:16 am

Hello,

I guess the parts you have selected should work, but here is some information about the parts I have used:

This is the 3.3 uF non-polar capacitor I have used:
http://www2.mouser.com/ProductDetail/WI ... DLXjc8zLm2

Please check the value of your 20 pF capacitor; when I click on your link there is a 68 pF capacitor displayed.

The resistors don't seem to be critical, but I have spend some cents more and used metal film types with 1% tolerance only.

I would recommend (and have used) a trimming potentiometer of 250 or 500 ohm instead of the fixed value 220 Ohm resistor. This allows easy adjusting of the input value.

Of course it's a good idea to start building on a breadboard with jumper wires. If everything works, you might start soldering.

Best regards,
Joachim

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Thu Jun 15, 2017 6:25 pm

Hi Joachim,

Thanks for the info.

That capacitor you linked, how is it designated to be non-polar?

Thanks!

Very best,

RTJoe
Oh, I get it now!
Oh, I get it now!
Posts: 24
Joined: Tue Jun 16, 2015 8:26 am
Location: Germany

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by RTJoe » Fri Jun 16, 2017 7:48 am

Hi Marty,

the capacitor I have linked is a film capacitor, these capacitors are nonpolarized by nature. The capacitor you have linked is an electrolytic nonpolarized (bi-polar) capacitor, that means actually two polarized capacitors in series. I guess both capacitors should work, but I'm no expert about the details.

Best regards,
Joachim

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Fri Jun 16, 2017 11:41 am

Thanks, that helps!

Very best,

User avatar
MalVeauX
Ohhhhhh My!
Ohhhhhh My!
Posts: 109
Joined: Tue May 09, 2017 7:58 pm
Location: Florida

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by MalVeauX » Sat Jun 17, 2017 1:04 am

Any chance there's a 20pF capacitor on there? I just looked under film and could only find a 22pF. Just trying to follow the PDF at the beginning of this thread, if that helps.

Very best,

User avatar
GreatAttractor
Almost There...
Almost There...
Posts: 551
Joined: Sat Jun 01, 2013 1:04 pm
Location: Poland

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by GreatAttractor » Sat Jun 17, 2017 3:35 am

All right, I'm joining the SSM club! Parts have been ordered - I'll use BPW34 diode too, and an LM224AN op-amp; parameters similar to LMC6484, we'll see how it goes...

I wanted to understand what's what, so I've tried to recall the electronics course (wasn't my favourite one) from studies, and also read the original article on solar scintillation by Dr. Seykora. Eq. (5) therein (page 391) gives the angular diameter of the average “seeing cell”:

ω = θI / <I>)

where θ is Sun’s angular diameter, ΔI the RMS of irradiation intensity changes (our second ADC input), <I> is average intensity (our first ADC input).

The 4.46 coefficient in output formula is due to the fact that we want to express ω in arc seconds, and the circuit magnifies ΔI by a factor of 20M/47k ≅ 425.5 (which we have to cancel out in our final calculation), while we can take the Sun to be ~1900 arc sec in diameter, so:

ω [arc sec] = 1900/425.5 * (ΔI / <I>) ≅ 4.46 * (ΔI / <I>)

As for the 10 000 samples taken for each returned seeing value, it seems it's due to Arduino's ADC read-out rate:
It takes about 100 microseconds (0.0001 s) to read an analog input, so the maximum reading rate is about 10,000 times a second.
i.e. we sample the RMS and the average over a period of 1 second.

The photodiode also checks out; according to specs, it produces 50 µA photocurrent at 1 mW/cm² irradiance. In full Sun (assuming 1000 W/m² = 100 mW/cm² irradiance), and converted to voltage and amplified 220x (due to the 220-ohm resistor) by the first op-amp, it should be about 1.1 V. Of course it's good to have a variable resistor to fine-tune it.

I'm wondering about filtering; Seykora's article mentions using filters which gave 220 nm FWHM at 510 nm. If the SSM is used during an Hα imaging session, shouldn't we e.g. slap a red filter on the diode to give more meaningful seeing values? Would there be any noticeable difference anyway?


P.S. Marty, I'm taking my chances with a 22 pF too.
Last edited by GreatAttractor on Sat Jun 24, 2017 10:13 pm, edited 1 time in total.
My software:
Stackistry — an open-source cross-platform image stacker
ImPPG — stack post-processing and animation alignment
My images

SW Mak-Cass 127, ATM Hα scope (D=90 mm, LS50 etalon), Lunt LS50THa, ATM SSM, ATM Newt 300/1500 mm, PGR Chameleon 3 mono (ICX445)

User avatar
PDB
Im an EXPERT!
Im an EXPERT!
Posts: 216
Joined: Mon Aug 15, 2016 4:23 pm
Location: Belgium

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by PDB » Sat Jun 17, 2017 3:41 pm

Hmm ... my answer from this morning seems to have vanished.
Interesting remark GreatAttractor. Now I remember the filters in the original document. I did a small test with a red Wratten 25 filter (that was all I had on hand). What I expected the input value dropped by approximately 0.2 but calculated seeing values did not change very much. (Difficult to compare in a short test, not reallt scientific, under varying sky conditions, more work needed.

Some remarks on the builds
A 22 pF capacitor will work (using it as well)
I am using the cheap Arduino Nano's but find these fairly unreliable. Also the mini USB connector is not very sturdy. With the SSSM i get sometimes hangups (could als be due to the one wire LCD display I am using, that sometimes hangs on startup as well). But I also made a focus controller with the same nano model and it works very well excexpt that it sometimes reset and all stored values are set to default. (Very annoying if you count on these positions to make sure the focuser does not go outside it boundary. The very strong stepper motor could the ruin the gearbox or the rack-and-pinion assist rail) So I decided to do some rebuilding and test it with an UNO which looks much better and has better usb connectors.

Regards,

Paul

User avatar
GreatAttractor
Almost There...
Almost There...
Posts: 551
Joined: Sat Jun 01, 2013 1:04 pm
Location: Poland

Re: DIY Solar Scintillation Seeing Monitor with FC support

Post by GreatAttractor » Sun Jun 18, 2017 9:01 am

I've just realized it's perhaps better not to use filters; if all/most of us use just a naked diode, it'll make sense to compare seeing values among all SSM users (not depending on people using exactly the same filters etc.).

Also, if I'm not mistaken, the U2 op-amp together with the 47k resistor and the 3.3 µF capacitor form an active high-pass filter with cut-off frequency of 1/(2π · 47k · 3.3µ) ≅ 1 Hz, so I suppose that's why the average (<I>) is obtained by summing over 1 s. The faster-changing portion of the intensity signal goes to the RMS calculation.
My software:
Stackistry — an open-source cross-platform image stacker
ImPPG — stack post-processing and animation alignment
My images

SW Mak-Cass 127, ATM Hα scope (D=90 mm, LS50 etalon), Lunt LS50THa, ATM SSM, ATM Newt 300/1500 mm, PGR Chameleon 3 mono (ICX445)

Post Reply

Who is online

Users browsing this forum: Yahoo [Bot] and 1 guest