The Moon

The Moon is back with its normal non-eclipsoid figure. 😀

Here is a picture taken with a Nikon D5100 mounted with a simple Barlow on a Celestron 115/910. I’ve had both the telescope and the camera for a long time now, but never took the next step of taking pictures. Thanks to the recently acquired barlow, this is a dream come true.

This is taken from a balcony in the middle of a big city, not exactly your ideal conditions for taking pictures of the sky especially during a hot summer with lots of temperature differences, but the results are still quite good and I have not applied any software fix on them. Exposure: 1/200 s, sensitivity 1000 ISO. Enjoy!

Note the difference in chromatic aberrations depending on the location of the details mostly due to the barlow lens, the following animation shows the same details taken in the center of the picture compared to the edge (1/100 s, 400 ISO):

Moon Eclipse + Mars / 2018-07-27

The sky was kind enough to let us see the moon eclipse yesterday for a short time, as it was quite cloudy. A very nice experience.

Of course, without forgetting its friend Mars (take your time, it’s an animation) :

The clouds also allowed for some creepy shots, you’d wonder if Freddy Krueger was around.


Note that these are raw photos. No filters.

Backups / Part 1

You have precious data

In this digital era, we all have data that we care about. You certainly wouldn’t want to lose most of your earliest baby pictures. 😀

That data is very diverse, both in its nature and in its dynamism. You have static backups such as your baby pictures, but also very dynamic data such as your latest novel. You also have a lot of data that you probably don’t want to back up at all, such as downloaded files and programs. Well, if those files are actually your bank statements, you may want to have a backup in case something goes awfully wrong.

Things go wrong sometimes

Many people store their “stuff” on their computer, and that’s about it. Then one day, the computer crashes. Bad news, the hard disk is dead. Woops.

The thing is, hard disks fail. In 30 years of dealing with computers on a daily basis, I’ve experienced on average one hard disk failure every 2 years, and I don’t even mention the countless floppy disks that died in my hands. 😀 Maybe I’m unlucky.  Maybe I use computers too much.

Regardless, I know people around me who also experienced hard disk failures and were not prepared for them. Some of them took it well, invoking destiny, others didn’t take it so well. But in any case, when it comes to data loss, destiny can be bent. And although I’ve had mostly hard drive failures, SSDs fail too, and in an even worse way since they generally give very little warning signs (if any) and the whole disk is gone at once, whereas on traditional hard drives it may still be possible to retrieve some of the data. USB keys and SD cards are no exceptions, I’ve found they fail quite often, even the ones from established brands.

Most of the time, trained and highly skilled professionals can recover most of the data using specialized equipment. For some examples of what is possible, you can check out this video channel of a very talented data recovery expert for amazing videos. But that comes at a cost. And recovering everything is not always possible.

You can cheat destiny with redundancy!

The good thing about computers is that, unlike paper data, digital stuff can be copied over and over, and that process is very easy and lossless. You just need to use this capability!

The first step towards minimizing the risk of losing data because of a hard disk failure is to set up a RAID (Redundant Array of Independent Disks). The basic idea is to spread your data and duplicate it on several disks, so that if one fails, your data is still on the other disks and you have cheated destiny. We will cover that in the second part of this series.

Redundancy Is Not A Backup

But keep this motto in mind: “Redundancy Is Not A Backup”. You have your array of disks and you can be sure now that even if one hard disk fails, you are still safe. Now, what if a second hard disk fails just after that? What if a power surge fries all your disks? Hardware failures happen, sometimes of something else (motherboard, SATA controller, etc) that even corrupts your data like it happened to this guy. Viruses encrypt all your data and ask for a 1 million $ ransom to get it back. Human error is always possible and you may mistakenly delete some important files. What if your apartment gets robbed? What if it burns or gets flooded?

This is why, along with redundancy, you always NEED backups. You should obviously not store them anywhere near your computer, ideally not even in your home in case something bad happens there. We’ll get into more detail about this in the third part of this series.

Encrypt your backups

Last but not least, as soon as you store your backups outside of your home, then comes the problem of privacy: what if someone comes across your backup and gets access to your data? You may not care about some of it being accessed by strangers, but you will probably want to shield some of your precious files from prying eyes. That will be the fourth and last part of this series.

3D printing – part 1

I have been curious about 3D printing for a few years now but never found the time and courage to finally take the first step and buy a printer. The fact is that the prices were quite discouraging for a simple hobby, at least that’s how I saw it.

I did have some real interest in 3D printing as I actually already printed a few items through a 3D printing website, such as a camera cache for my tablet and a magnet holder for my drinking glass.

While the first one is a classic, you might wonder what the second one is for. I invite you to check the Professor Luc Montagnier’s research on water, it might give you a few clues, and this is just a little experiment of mine. Since I have been drinking that polarized water (for a few years now), I have not been sick, although there are still some things that could be improved in my lifestyle regarding health.

Anyway, back to 3D printing, the cost of delegating the printing to a 3rd party is quite prohibitive. The second piece cost a mere 30 euro + shipping. And I ordered 2 of them. You’d better not make any mistake in the design.

Then, in December 2017, I found a 3D printer kit on Gearbest on sale at 100$. I thought “What the Heck, this is the equivalent of printing 3 of my magnet holders!”. And I had many other projects in mind but I was reluctant to make them because of the inferred cost. So I just bought the printer, although I had some idea that as it was a kit it would require quite a bit of attention and time. Well, that’s an understatement.

The thing is that 3D printing is not yet for everyone. Not only as a bare kit, but also in general. Even high-end 3D printers are still having a lot of issues, from what I read on the Internet. I’m actually glad that I bought a kit:

  • it was very cheap,
  • I got to get familiar with every single part and detail of the printer,
  • if anything fails I always have a fix at hand.

The last point may be the most important of all. If you have a stock printer, when it fails and you don’t want to burn your warranty, you have to go back to the seller or the manufacturer. That’s a lot of cost, time and energy (communicating, explaining your problem, sending it to the post then waiting for it to return, etc.), when you could actually use that time to fix it yourself.

Of course, the thought of printing your own stuff is very thrilling. But do bear in mind that 3D printing is very demanding, and before jumping into it, you should know what you are putting yourself into.

Although I’ve had my printer for just 6 months, I have already printed quite a lot of things. In fact, the printer has been active for almost 2 full months:

And I have also spent some time transforming it, fine-tuning, fixing problems, etc, and it is significantly different from the original kit now:

Anyway, what I can say is that it is also very demanding, in time and energy. Many things can go wrong with that technology, especially if you start from scratch with a kit:

  • there are obviously heated parts (at least 200°C, that’s 392°F), which can be dangerous, including the hazard of burning yourself,
  • mechanical problems including bending parts,
  • precision is key, a fraction of a millimeter can make the difference between failure and success,
  • sensitive electronics (a motherboard, an LCD screen),
  • strong currents that can represent a fire hazard, especially as the basic equipment that comes with the kit is not exactly 100% safe,
  • melted plastic, with all its potential caveats (toxic gas, fluidity, adherence depending on the temperature, stuck nozzle, etc.),
  • bugs in software and firmware,
  • moving parts and wear (soldered wires coming out…), strongly vibrating parts which can cause loose screws, detached pins, etc.),
  • noise issues…

I think you may get my point by now. Every single of these aspects is sensitive enough to cause printing to fail. Just keep this motto in mind: “If it is possible for anything to fail, it WILL fail after some hours of printing.” Thus you want to have everything safely secured so that there no possibility left for it to fail.

In order to achieve this, many different skills are required:

  • feel at home with computers (obviously) and have some minimal knowledge of electronics is definitely a plus,
  • fixing mechanical parts, including very small and detailed pieces,
  • patience (that’s a big one as printing big parts can sometimes take a full day or more – my record is 37 hours),
  • being capable of soldering and making your own wire connectors,
  • unless you only want to print things that have been designed by others, 3D designing skills, so that you can take full advantage of your printer, creativity is definitely a plus here,
  • coping with the constraints inherent to 3D printing (minimal wall thickness, connection thickness and detail, as few hanging parts as possible, etc.),
  • finding an appropriate place to put the printer in your home (if you plan to print ABS you definitely want a ventilated area),
  • evaluating the physical resistance of printed pieces. This point is not a joke, especially as heat can come into play with certain materials:

In this particular case, it was a combination of underestimating the strength of the piece compared to its width and the weight it was supposed to carry, but the color with which I printed it was quite sensitive to the heat from the sun, and that was PLA. After printing it in white and a bit thicker, I don’t have any problem anymore although the temperatures in France are currently reaching 35°C.

So yes, there is a lot of fine-tuning, trial and error in 3D printing. And changing any single thing in your habits, including the filament brand or even color can break a print.

However, all this said, 3D printing is a lot of fun!

Have a look at my thingiverse page where I share pieces that can be of use by other people (which is not always the case: 3D printing is mostly about making pieces that fit exactly your own needs – not necessarily your neighbours’).