NextBase 312GW dash camera first impressions

Posted on May 9, 2018 by james

I’ve had a few drivers pull particularly bizarre stunts on me of late, not to mention having had to dive into the hedge because a car has come around a blind bend in the middle of the road once or twice, so I decided I’d get a dashcam for my car with a view to fitting a second to my wife’s car if I got on with it.

For no particularly quantifiable reason other than that it wasn’t hideously expensive I bought the NextBase 312GW with a permanent wiring kit. The 412GW perhaps looks nicer and has a larger display, but actually I wanted something that would be fairly unobtrusive when fitted to the windscreen, so smaller was a bit more desirable in this case.

First impressions are that it’s very neat for the price and being removable from the mount is quite handy. It’s easy to use and the recording of speed and GPS data on the videos is good. I’ve not investigated the still mode or anything like that because I probably won’t use it that way. I also liked the fact that it is possible to turn off the “NEXTBASE” logo that appears on the top left of the screen.

I’ve tried running the camera in 1080p and 720p modes and I felt that the 1080p contains more visible compression artefacts than 720p. Here’s a 1080p image:

To me the “stripe” down the centre of the road looks quite “blocky”. In this 720p frame the entire image looks better to my way of thinking:

For the time being therefore I’ve left it in 720p mode.

Small niggles are that it’s a bit awkward to get the SD card in properly with fingers like mine (and some of the documentation says that 32GB is the maximum size whereas elsewhere it says 128GB) and that the “mass storage” mode which I assume should allow videos to be pull straight onto a PC just as they would from a USB stick wasn’t stable and kept disconnecting.

I checked the firmware version which was R04.0. On the website there’s an update to R04.4 that I downloaded, but despite following the instructions I just couldn’t get the camera to update. I opened communications with their support team, but as it happens the failure worked in my favour. In reading more about the upgrade from various forums it turns out that later versions of the firmware have removed the ability to turn off the logo on the videos. It is possible to get firmware without the logo however, but support only provide it on a case-by-case basis.

I downloaded the new R04.6 firmware (without the logo) and still couldn’t upgrade, so had to start experimenting. I discovered that formatting the SD card on the camera itself, on Linux or on MacOS and then copying the files on just didn’t work. In the end I had to do a full format on Windows 7 and copy the files on from that, at which point the upgrade worked first time. I have no idea what the difference should be as they all seem to be compatible with each other, but clearly the camera doesn’t like it.

The upgrade also seemed to get the mass storage mode to work properly which is good news.

Now I just need to get the wiring harness fitted to the car and use it for a bit.

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Star Adventurer Polar Scope Alignment

Posted on May 9, 2018 by james

Having checked the tracking accuracy of my Star Adventurer already, I wanted to make sure the polar scope was correctly aligned before trusting it to location the pole using Polaris. There are a couple of things to worry about for this: first that the polar scope is concentric with the RA axis and second that it is in the correct rotational alignment with the setting circles.

The first should be easy to test but can be a bit of a pain to sort out. I set the mount up during the day and adjusted it so the cross of the reticle was over a distant object. Rotating the RA axis should leave the cross over the same spot. When I first tried this I took some photos at different positions:

There’s clearly a slight “wander” there, but I wasn’t happy that it was due to misalignment of the polar scope. I took off the counterweight bar and repeated the test, this time finding that the cross did indeed stay in the same position. Clearly the weight of the counterweight bar does induce some flex in the mount. I think that means that balance is going to be quite important when it comes to putting actual kit on the mount.

The good news of course is that no adjustment is required there so I don’t have to play with the three adjustment grub screws at the eyepiece end of the polar scope.

That done, the next step is to check the rotational alignment of the polar scope. Years ago I read that Polaris transits the northern celestial pole at midnight on 1st November every year (at the prime meridian). So if the index ring is aligned with a zero offset on the inner scale on the date ring, then the RA axis rotated so the rings have 1st November aligned with midnight then the polar scope should have midnight and 6 o’clock in a vertical line.

I’ve never questioned this initial piece of information, so I thought I should just confirm it this time around. It doesn’t seem to match the results from Stellarium. Here is the position of Polaris at midnight on 1st November this year:

At transit it should be on the orange 0 degrees line. Clicking on Polaris or using “Find” to locate it gives a lot of information in the top left of the screen including the “hour angle”, which should be 00h00m00.0s at transit. In fact it’s 15 minutes out. Quite possibly that’s within the margin of error of the mount design, but I thought I might as well get it right, so advancing a few days I found that midnight on 5th November is very close:

And again checking the hour angle it’s 17 seconds out which I think I can live with 🙂

So back at the mount I set the index ring to zero offset, rotated the RA axis so the rings read midnight on November 5th and looked through the polar scope expecting 12 to be at the top and 6 vertically underneath it.

No such luck. I reckon it’s between ten and fifteen degrees out 🙁

The next step then is to find some convenient vertical edge to line the polar scope up against. Surrounded by the natural world as my house is, there aren’t too many handy verticals. Even the walls of my house are not vertical. Fortunately I found a door that was sufficiently far away to focus on and rotated the RA axis to get the polar scope to coincide with that:

Without moving that I then turned the date ring to read midnight on 5th November:

And finally loosened the locking grub screw on the index ring and moved the index to be at the zero degree meridian offset mark:

(Apologies for the quality of these last two photos. I turned off the flash as it was making the dials almost impossible to read.)

Locking the grub screw up again the job is complete.

As I’m a few degrees west of Greenwich I shan’t use the index ring at this setting when I actually want to use the mount. I’ll rotate the date right a little to give the right offset. Then rotate the entire RA axis to show the correct time and date. That should account for the fact that being a bit rural and backward, the stars are ten minutes late getting here 🙂

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“May Day” brew

Posted on May 8, 2018 by james

I’ve been meaning to get back out to the beer shack for a while but there have been so many other things going on of late that time has escaped me. This bank holiday weekend however I put aside a day when I was definitely going to brew. I didn’t have any specific plans regarding what I was going to make, so I ended up just throwing some stuff together out of ingredients I had left over. In the end I finished up with something along the lines of:

8.5kg pale malt
140g caramalt
310g Special B
120g crystal malt

These all went into the mill:

which took a fair bit of effort to grind my way though. Looked ok once done though.

I underlet my mash tun, feeding the water in through the same valve that I use to run off the wort when the mash is complete:

I then spent a happy hour and a half doing other jobs before returning to sparge and run off the wort:

For the boil I used a combination of Target and Progress hops for bittering and late addition, finally running off about 35 litres of wort, a little darker than I expected but we’ll see how it looks after fermentation.

Once chilled I transferred the wort to the fermentation vessel in my heated cabinet together with a hefty shovel of Phoenix hops for aroma and a batch of S-04 yeast that I’d kicked off in a light DME solution twelve hours previously:

No idea how it will turn out, but a quick check on the hydrometer suggests that it could be quite strong.

Given the OG figure and that it was brewed on the first May bank holiday, I think I shall call this one “M’aidez”.

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Swimming, 2nd May 2018

Posted on May 8, 2018 by james

My first attempt at my usual set with a reduced target time:

400m front crawl warm-up
25 x 50m front crawl, target time 54s, rest interval 21s
200m front crawl swim down

Today turned out to be something of a mess. A couple of times I was delayed by other swimmers and then about five reps from the end two new swimmers got into the pool and decided they were going to swim up and down the lane line I was using (no lane ropes or anything today). Quite why they decided to do that when there were only five people in the pool and plenty of room elsewhere (and when I was clearly the fastest swimmer in the water at the time) I really have no idea.

Anyhow, I managed all the reps in under 54 seconds, but I don’t feel I can claim it as a great success because my rest intervals were fairly messed up. I’ll do it properly again next time.

USRPT distance this year: 35,000m
Total distance this year: 75,350m

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Swimming, 1st May 2018

Posted on May 2, 2018 by james

In line with “the new regime” I didn’t do a USRPT set today, but instead spent the entire session working on my tumble turns. I’ll go back to USRPT tomorrow and try to build in what I’m practising. The most significant problem I have in executing the turn at the moment is probably that I’m quite weak when my left arm takes the last stroke. But there are other things that need working on too, such as timing of the last breath and not getting messed up if it can’t happen when I want it to. Being able to turn in the shallow end confidently wouldn’t go amiss, either.

I envisage working on this for a while. I don’t think a single session is sufficient practice to improve it, but I need to separate it from the USRPT work so I can focus on the exact details rather than also worrying about getting back to the wall in time.

USRPT distance this year: 33,750m
Total distance this year: 73,500m

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Swimming, 30th April 2018

Posted on April 30, 2018 by james

Back to USRPT today. Hopefully my last attempt at:

400m front crawl warm-up
25 x 50m front crawl, target time 55s, rest interval 20s
200m front crawl swim down

I led off on the 50m reps a bit fast, hitting 46/47s for the first few. That wasn’t going to be sustainable so I had to back off a bit for the rest. After that they seemed to come relatively easily and I made the full 25 reps without any real drama.

I’m going to try to do five sessions this week, alternating between skills work and USRPT sessions and we’ll see how it goes. Then it’s down a second on the target time for Wednesday 😀

USRPT distance this year: 33,750m
Total distance this year: 71,900m

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Swimming, 27th April 2018

Posted on April 30, 2018 by james

Got into the water today and started doing my warm-up, but my arms just weren’t having it. They just felt too tired.

Not wanting to waste the session I decided to spend the rest of my time doing skills work, specifically practicing my tumble turns. I’m still weaker when my last breath is to my right and I lead the turn with my left arm, so getting some work in on that is definitely worthwhile.

Normal service will be resumed on Monday.

USRPT distance this year: 32,500m
Total distance this year: 70,050m

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Star Adventurer Tracking Accuracy Results

Posted on April 27, 2018 by james

After running for 24 hours I stopped the SA running and measured the distance from the finishing point to my initial mark:

Looks like it’s gone a bit too far. However, that’s in a solar day, not a sidereal day, so let’s do some calculations…

The radius of the circle described by the end of the counterweight bar was 305mm, so in 24 hours it had travelled 1916mm (circumference of the circle) plus 2mm over as measured off the wall. 1918mm in all. A sidereal day is 236 seconds shorter than a solar day, so in a sidereal day it would have travelled ( 86400 – 236 ) / 86400 x 1918 = 1913mm — 3mm short of where it ought to have got to.

That 3mm is equivalent to about 2191 arcseconds over the course of a sidereal day, or about one arcsecond too slow every 39 seconds. Imaging at a scale of, say, ten arcseconds per pixel, it’s clearly going to be a while before any error is apparent due to the tracking and quite possibly polar alignment will become a problem first.

I am slightly tempted to do attempt a more accurate measurement using a laser pointer to mark the position with more distance between the mark and the mount, but perhaps that can wait until I’m really bored 😀

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Swimming, 26th April 2018

Posted on April 26, 2018 by james

Repeating the same set from earlier in the week:

400m front crawl warm-up
25 x 50m front crawl, target time 55s, rest interval 20s
200m front crawl swim down

This felt really tough today, though I didn’t drop below 50s for the first half of the set. As I got towards the last eight reps however, my arms were feeling very tired and it was mentally quite hard to keep pushing.

Nonetheless I managed all 25 reps and mostly below 50 seconds which is very pleasing.

I’d like to do a bit more now as there’s some time spare in most of my sessions, but 25s are going to be tricky without a pace clock that I can see from both ends of the pool (supposed to be fixed by the end of April allegedly, though I’ve been prodding them about it since the start of September). However, I am only swimming four times a week because I just can’t do five consecutive USRPT sessions like this at the moment. There just isn’t enough recovery time for me. I could instead alternate between USRPT sessions and pure technique sessions (so USRPT Monday, Wednesday and Friday with technique work on Tuesdays and Thursdays), so I’m going to give that some thought in time for next week.

USRPT distance this year: 32,500m
Total distance this year: 68,650m

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Checking Star Adventurer tracking accuracy

Posted on April 25, 2018 by james

I wanted to get this done now so I can get any problems sorted before actually wanting to use the mount in anger, so I’ve set the entire mount up with the counterweight bar almost touching a wall. I marked the position of the top of the counterweight bar on the wall. It’s just about visible in this picture taken after the mount had been running for a couple of minutes:

Initially I had some problems powering the mount. I tried a PC and a couple of USB hubs and the mount wouldn’t power up from any of them. Eventually I sat a laptop below the mount and plugged the USB power cable into that which appears to work without a problem.

Now to set an alarm to remind me to check the position of the counterweight bar tomorrow when it should have done a full rotation.

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