Baby steps around the Crescent

Posted on January 15, 2020 by james

With all the miserable weather we’ve had I’ve finally got things organised to do a bit of processing. Well, organised to do a bit of learning about processing really. When Photoshop-wrangling is required, I am only an egg.

So, this is a first pass at processing my data from the Crescent. Something of a motley collection of files, with five hours of Ha, four hours 45 mins of OIII, three hours of luminance, one hour 45 minutes of each of red and green and an hour of blue, all as fifteen minute subs, using my Atik 314L+ and 80ED. There was more blue, but it was awful so I threw it away, and in the end I didn’t use the luminance data (which is what I captured first). So, this is actually HaR for the red channel, OIIIG for the green and straight blue, reusing the HaR as luminance, totalling fourteen hours and 15 minutes integration time, scaled to 50%.

(I’ll put a larger image linked from the DSO section later).

I’m not exactly unhappy with it, but not entirely happy either.

There’s no sharpening and I think I need to get my head around that. I did try some deconvolution, but I wasn’t happy with the results. I’m wondering if I should perhaps have combined the OIII data with the blue channel as well as the green. I think there’s more there than really shows up and perhaps that would make it stand out a little better. At the moment I think the green shell looks like an artefact when I’m pretty sure it’s genuine data.

It would be nice to have the stars a little better controlled, too. Sharpening might help with that, I guess, but it’s something else to work on.

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Juicing apples

Posted on January 15, 2020 by james

As ever it took longer to get around to this than I’d hoped, mostly because we’d been somewhat short of weekends with suitable weather. However, eventually I had the opportunity to assemble all the various bits and pieces required to press the apples and cleaned them. Then the children and I got to work.

The first stage is to chop the apples up into small pieces, for which we use what is little more than a stainless steel garden shredder.

The apple goes into my home-made press (though I bought the tray and modified it to fit a drain — it’s the sort of thing used for keeping food in canteens and suchlike). The drain fitting is a stainless deck drain as often fitted on boats, I believe, and on the underside is a stainless ball valve.

Just like a “traditional” cider press the apple is added in layers inside a “hair”, which in my case is squares of net curtain.

Not quite so traditional are the press boards that allow room for the juice to run out. I made them from squares of HDPE (the same sort of stuff that plastic chopping boards are made from) and cut grooves in each side using a circular saw with the blade depth set to just less than half the thickness of the material.

The grooves allow the juice to run very freely when the pressing starts.

Also not quite “traditional” is the power for the press. In my case a twelve tonne bottle jack. It does a very good job though. The cheese compresses down to no more than half its original size by the end. I reckon I could probably go a bit further, but I’d need a more powerful jack and probably a metal frame for the press. A wooden frame suits me though.

What’s left in the press is this. Like apple cardboard.

And the final product. (That’s only a half pint mug, honest. Not that it stopped my son drinking a couple of pints of it 🙂 It does taste absolutely fantastic.

All told we managed to get sixteen gallons of juice from the ten sacks of apples that I collected back at the end of October. We did have to throw out a few bad ones, but considering they’ve been sitting in the sacks for over a month it wasn’t too bad.

The next stage is to bottle and pasteurise it. I don’t have a proper pasteuriser, so I make do with my beer boiler, putting the bottles neck-deep into water, raising the temperature to 70C and holding it there for twenty minutes before capping the bottles. It’s a bit of a hack and I really need to make a proper pasteuriser, but for now it works.

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Restoring an AAG rain gauge #1

Posted on January 15, 2020 by james

I’ve had one of AAG’s rain gauges for years. I’m not sure they make them any more, but I believe they were someone else’s design anyhow. In the end it gave up because it was bunged up and the electronics weren’t working. Rather than buy or build a new one I decided I’d open it up and see what I could do to make it live again.

As it turns out other than the rocker for catching the drops of rain there’s really not much inside:

The battery was dead, but appears to be “welded” onto the board so I decided I’d leave it alone. It’s only there to provide a battery backup for the counter memory and I’m hoping I shouldn’t have a problem with power there.

So my refurbishment was mostly limited to completely disassembling all the parts and cleaning them up, then reassembling it carefully.

I also have some cat5e cable with a UV-stable sheath, so I removed the old cable (the red and black wires in the above pictures) which wasn’t going to be long enough anyhow and replaced it with some of the cat5e, in a length sufficient to reach back to the Stevenson screen.

Testing on my desk by flipping the bucket with my finger actually suggested that I might still have a problem with double-counting “tips”, but I decided I’d deal with that later if it was a problem in actual use.

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Geeking out

Posted on January 15, 2020 by james

I’ve put quite a bit of time into oacapture and oalive this year and hopefully they’re the better for it, with a new release coming soon. Github demonstrates the depth of my efforts:

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DIY Stevenson screen #3

Posted on January 15, 2020 by james

My Stevenson screen is now finally in place, mounted on the outside wall of the observatory warm room, allowing cabling to be routed into the warm room for collecting the data. Initially the instruments will be connected to the warm room PC and I’ve run some cables through a bit of spare conduit for that purpose.

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A bit of a catch-up

Posted on January 15, 2020 by james

It’s been a while since I last found time to post anything thanks to life being quite busy, even over Christmas so I thought it was time for a bit of a catch-up.

Swimming hasn’t really been going that well. I think I’ve possibly just been pushing myself too hard in all things of late and my body is struggling a bit to keep up the pace. I have restarted properly this week however, so more of that later.

First piece of news after my last post however is that it snowed a few days later! In mid-November! I don’t recall that happening in a very long time.

Since then it has been very mild and only looks like it might to start getting colder again this week. In mid December we were having temperatures of over 10C during the day quite regularly.

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Sloe, sloe, prick, scratch, sloe (ouch!)

Posted on November 10, 2019 by james

I spent an hour or so this afternoon exploring the hedgerows and collecting sloes. It’s a job I’ve put off for a couple of weeks waiting for the rain to stop and the days to turn colder. It seems the amount of rain we’ve had has caused many to split and start to rot, but there were still plenty left and I managed to collect three or four kilos before I’d had enough of the cold. My forearms are also covered in scratches now. Blackthorn is really quite a brutal plant to tangle with.

Anyhow, they’re off to the freezer for a while to save me having to pierce the skins before I use them to make sloe gin and vodka. I might also keep some back to make sloe cordial.

When I returned to the kitchen I found that I wasn’t the only one labouring with the autumn harvest. A very appealing selection of bottled pears had appeared on the worktop. I shall look forward to trying them…

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In a “cloud sandwich”

Posted on November 10, 2019 by james

I left the workshop whilst working on my Stevenson screen and looked across the valley to the east through the sycamore trees. Something wasn’t quite right, but it took me a little while to work out what. It was the colour that was wrong. Where it should have been a mix of green and autumnal reds and yellows, there was just greyness beyond. Whilst the air was clear at my altitude, there was a thick layer of cloud above, and another lower down in the valley. It was clearing rapidly so this photo sadly doesn’t do it justice.

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DIY Stevenson screen #2

Posted on November 10, 2019 by james

I had to wait a fair while for the paint to dry (and it isn’t really properly hardened off yet), but that wasn’t a major issue as I was also waiting for some stainless screws to arrive. Yesterday I finally got around to assembling all the parts so far and this is how it now looks.

I have a couple more sections of 30mm square timber to fix across the back on the inside to allow me to fix the sensors in position, but the major piece left to do is to fit the upper roof. That has all been painted with undercoat and hopefully this week I can get the final coats on so it can be completely assembled and put into place next weekend.

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1-wire weather sensors on Linux

Posted on November 10, 2019 by james

Some time ago I had a 1-wire weather station and a number of other 1-wire weather-related sensors run from a Linux server. It wasn’t hugely reliable because the cable run was really a bit too long, but with a bit of messing about I got it working with some software called OWW. Unfortunately a few years back the weather station blew down in a storm and I didn’t get around to putting it back, but now it is time to get things sorted.

I have a USB adaptor for my 1-wire network. Plugging that in together with a number of the 1-wire devices reveals that the world has changed somewhat, and not entirely for the better. It seems that recent Linux kernels recognise some 1-wire devices directly and create device entries for them in the file system tree, but they don’t recognise everything I have. And in fact, on my 64-bit Intel desktop running Mint 19, the drivers cause a kernel panic 🙁

Switching all the hardware to a Raspberry seemed to work better. Perhaps the drivers are more stable in a 32-bit environment. I still have the problem that not all the sensors are recognised however.

A little investigation of the OWW code reveals that it expects to manage the 1-wire devices directly, so I decided to move back to my desktop, but blacklist all the standard 1-wire drivers and allow OWW to do its stuff. I did have a few problems getting OWW to build on Mint 19. Getting the correct set of dev packages installed took a while and then I had to edit the code so the fonts didn’t come out a ridiculous size, but eventually I got there. Then I found that it still couldn’t read the devices. Fortunately my experience with astronomy cameras stood me in good stead and I realised I’d need a udev script to make the USB controller readable by my user id.

That done, I plugged in the circuit board of my AAG weather station, a pressure sensor and a combined solar/temperature sensor and fired up OWW again. It lives, Igor!

OWW whines about an error reading the wind direction ADC, but I think that’s because I dismantled the weather station so I could remove one of the 6P6C plugs (the cable tore out of the plug when it was blown down) and replace it. I’ve not reassembled it yet. I’m actually half-tempted to try to 3d print an entire new housing as the original has somewhat degraded in the sunlight.

Getting this bit of software working is actually more than I need in fact. There’s a non-GUI version that can just log the data to a database which means it can be pulled out to be used however I want.

I also have a combined temperature/RH sensor that I want to try out (need to make up a cable for that, but it shouldn’t take long) and some loose DS18B20(?) temperature sensors I can test.

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