Fix for Flutter error : No toolchains found in the NDK toolchains folder for ABI with prefix: mips64el-linux-android

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Trying to run a slightly older Flutter project, the build sometimes fails with the error : 

No toolchains found in the NDK toolchains folder for ABI with prefix: mips64el-linux-android

The problem is that -> mips64el-linux-android is missing in the NDK as it got deprecated some time ago.

What usually 🙂 works is changing 2 files in the Android folder of the project.

Open android/gradle/gradle-wrapper.properties and change this line:

distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip

to this line:

distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip

Open android/build.gradle and change this line:

classpath 'com.android.tools.build:gradle:3.0.1'

to this:

classpath 'com.android.tools.build:gradle:3.1.2'

Do a : flutter clean and rebuild. Happy coding!

Lathe – Threading gear calculator

Having bought a lathe for various DIY projects back in 2015, i quickly discovered the need to cut some unusual thread pitches (Astronomy adapters in particular have some of the weirdest out there).

The lathe manual (or the housing of the transmission system :D) , usually provides some information regarding the gearing for the most used ones, such as 0.05mm, 0.1mm, 0.2mm, 0.4mm, 0.5mm, 1mm and so forth.

But nothing for lets say an M42x0.75 adapter widely used in photography and astronomy!

While looking through the web in 2016 for a lathe gear calculator there was none to be found, that took into consideration the spindle to gear A ratio.
The spindle in this specific lathe (and many other brands from what i have read ) has a ratio of 4.5 turns. So in order for gear A to make a full turn the spindle makes 4.5 turns.

Without this number the usual quadrant calculations for gearing lathes, obviously fails and your thread pitches are not what you have expected at all 😛

Here is a very crude calculator for finding out possible, combinations of gears in a metric lathe (that is, a lathe with a metric leadscrew although it can cut some imperial threads by approximation), in order to produce the desired pitch when cutting threads!

Do note that some of the produced combinations, are not feasible at all for the time being, but I will upgrade it when time permits.

Lathe threading gear calculator

Have fun!

 

New astronomy website!

Astronomy is a really broad subject. Same goes for astrophotography and all the weird gimmicks of this hobby.

Because for the most part of the year, I went full berserk mode into both and have gathered allot of images, data, procedures and various tutorials, which would kind of hijack this personal blog I decided to move astronomy and astrophotography into its own separate – special website 🙂

So if you are into any of those things or maybe like “nice”  images of the cosmos, do visit the website :  http://www.starcanvas.org

 

NGC6910 Gamma Cygni and nebulosity

HaRGB version of the beautiful Gamma Cygni and surrounding nebulosity region.

NGC 6910 is a Y-shaped cluster oriented northwest southeast. The two brightest stars are of magnitude 7.NGC 6910 is a small cluster, only 10′ in diameter

NGC6910 Gamma cygni by Marios Tsalkidis

The southernmost star is SAO 49563 (or V2118 Cygni), a variable star of spectral type B1.5Ia. Gamma Cygni, not far off the galactic plane is subject to a great deal of interstellar extinction and reddening from interstellar dust. The dust selectively absorbs and scatters blue light (roughly 1/wavelength), so when you look at a star through dust it will appear redder than it really is (basically the same reason the sun is reddened at sunset). The intrinsic B-V color of a B1.5Ia super giant is -0.2. The observed color is 0.83, about the color of a K0 dwarf or a G5 giant, so the star appears yellowish to the eye. Notice the yellow stars in the cluster, caused by interstellar dust, and the bluish-white stars in the vincinity of NGC 6910.

Technical details
Sky-Watcher 80ED Pro Black Diamond
SBIG 8300M
HEQ5 Pro
QHY5
Skywatcher .85x Focal Reducer & Corrector
PixInsight,  Main Sequence Software SequenceGeneratorPro
Accessories: Starlight Xpress Starlight Xpress FW 5*2”
Resolution: 1676×1266
Dates: June 13, 2015

Frames:
Baader 7nm Ha 2”: 10×300″ -5C bin 2×2
Baader Blue 2″: 10×120″ -5C bin 2×2
Baader Green 2″: 10×120″ -5C bin 2×2
Baader Red 2″: 10×120″ -5C bin 2×2

Integration: 1.8 hours
Darks: ~50
Flats: ~10
Bias: ~300
Avg. Moon age: 25.75 days
Avg. Moon phase: 15.29%
Bortle Dark-Sky Scale: 2.00
Temperature: 17.50

Annotated version :

NGC6910 Gamma cygni Annotated by Marios Tsalkidis