Few words about me:From very childhood I loved computers, electronics, lasers, sulfuric acid and liquid nitrogen. I always wanted to be making microchips, UAVs and see nuclear explosion.
Now I am doing software engineering and in the spare time - some microelectronics and physics/chemistry experiments.
I live and work in Russia, Moscow.
Sony a7II: Time for Full Frame (and some fake RAW controversy)
Finally I've bought my first full-frame digital camera - Sony A7II, on ebay as usual. While everybody were excited about A7RIII - I was quite disappointed: same sensor as in A7RII and still not solved fake RAW issue (it's there for all Sony camera's though). Why it is called fake RAW? Sony cameras has noise reduction algorithm which you cannot disable. It kicks in at long exposures and is applied even in RAW(!!!!), which completely ruins whole idea of RAW files (=direct stream of data from the imaging sensor for further advanced processing). The most obvious effect of this forced "noise reduction" is erasing 2/3 of the stars at the photos of night sky. You can read very detailed research of the problem here and you can also sign petition to Sony to finally fix it.
As my personal punishment to Sony I've decided to skip few camera generations: I will have fun in full frame with A7II for a while, just like 2 years ago I've started to get experience in E-mount with Sony NEX-5, which was ebayed for 110$. Hopefully some day they will release something like A9RII with 60mpix sensor and fixed fake RAW issue - this camera will be worth to buy new :-)
Glad that I did not ever bought full-frame A-mount camera (A900/A99 - it would have wasted much more money after re-sale), and a little bit sad that 3 years ago I've blindly bought Sony A77II instead of some E-mount camera (like a6000) which was already available at the time...
Slicing ruby like butterHad some success cutting synthetic Ruby rods using very thin (0.15mm) diamong cutting disk. These rods were once made for high-power pulse lasers (they were eventually made completely obsolete by much more efficient Neodimoum lasers). Chipping at the very last moment of the cut is still not completely solved.
Photo cannot show incredible fluorescence of Ruby at 692nm - longest red wavelength, almost infrared... Deepest and most intense red that human eye can see...
Blade Runner 2049Impeccable sci-fi setting and story yields it solid 10/10 rate in my view. Hits perfect spot of what I would consider ideal sci-fi movie. Would recommend to watch it in the morning, with lowest theater occupancy.
Is 16 terabytes Enough For Anyone?At some point of life everyone starts to feel that 16Tb storage is no longer enough and it's time to expand it. I am a little scared to think how did I managed to currently occupy 12.68Tb. But there is no time to investigate, let's throw some hardware at the problem!
After routinely adding yet another 4Tb disk to RAID6 array and trying to resize ext4 partition I was puzzled by the message:
That was totally unexpected. EXT4 does not support partitions larger than 16Tb? It appeared that it did not up until somewhat recent time. 5 years ago that would have been a brick wall, 2 years ago I would have to wrestle a little with bleeding edge resize2fs/kernel and now it all works on-the-fly out of the box. One just need to convert this ext4 partition to 64-bit format:
root@lbox2:/var$ resize2fs /dev/md1 resize2fs 1.43.4 (31-Jan-2017) resize2fs: New size too large to be expressed in 32 bits
root@lbox2:/var$ resize2fs -b /dev/md1 resize2fs 1.43.4 (31-Jan-2017) Converting the filesystem to 64-bit. The filesystem on /dev/md1 is now 3907015424 (4k) blocks long. root@lbox2:/var$ resize2fs /dev/md1 resize2fs 1.43.4 (31-Jan-2017) Resizing the filesystem on /dev/md1 to 4883769280 (4k) blocks. The filesystem on /dev/md1 is now 4883769280 (4k) blocks long. root@lbox2:/var$ mount /var/bigfatdisk root@lbox2:/var/bigfatdisk$ df . -H Filesystem Size Used Avail Use% Mounted on /dev/md1 20T 14T 5.9T 71% /var/bigfatdisk xy@lbox2:~$ cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md1 : active raid6 sdf1 sdg1 sdh1 sdc1 sdb1 sde1 sda1 19535077120 blocks super 1.2 level 6, 128k chunk, algorithm 2 [7/7] [UUUUUUU] bitmap: 1/466 pages [4KB], 4096KB chunk, file: /var/md1_intent.bin unused devices: <none>
I remember in the late 90's i've been to ftp.cdrom.com - it had enormous 0.5Tb array: it felt like absolutely insane volume of data (I had 850Mb HDD at the time). Probably readers of this article in 2037 would have 1024-layer 3D phase-change memory with 64Tb in 2.5" drive. Good for you, readers from the future... Although it is also possible that popularization of online-content, streaming and cloud apps will make it almost obsolete to have large local storage (with a few exceptions).
BTW since I went for softraid at home about 8 years ago - I had not a single HDD failure (about 50 hdd-years). Still pays off - much less worries about at least 1 thing...
Aftermath of X9.3 solar flareSolar minimum they said... It will be spotless they said...
More Deep SpaceFinished processing photos from my last trip so we all can see the results.
Let's start from Milky Way near M6, M7 (exposure 85x3.2s):
Deeper look at the center of our galaxyThis is my first experience in deep sky photography. Best place to start is center of our galaxy - where deep sky objects are densely packed.
128 shots @3.2 seconds exposure each. Sony NEX-5 with Canon FD 55mm F1.firstname.lastname@example.org. All frames were stacked using DeepSkyStacker, plate solving and annotation is done by All Sky Plate Solver. There were 2 shooting sessions for this subject - both at Tenerife mountains, at heights 1500 and 2200 meters. Sky glow was twice brighter at 1500m, so this batch of 106 shots was not used in final stacking. Even at 2200m conditions were far from perfect - wind from Africa carried visible dust which contributed to background brightness.
Next time camera with more modern sensor will help as well as less-bright (!!) lens: F1.2 was making bright stars too large even when stopped down to F2.2. And surely, sky tracking mount will allow much longer exposures and higher image SNR.
On mouse over - annotation. Higher resolution on click.
Chemiluminescence of CPPO with dyes
Finally it worked! It is much more complicated than Luminol reaction. The hardest logistical part was finding CPPO (Bis-[2,4,5-trichloro-6-(pentyloxycarbonyl)phenyl]oxalate). Dyes are Fluorescein and Rhodamine R/6G. Catalyst/acidity regulator is Sodium Acetate (more common bases like NaOH or NaHCO3 were not working). It's conventional synthesis from baking soda and acetic acid is messy and painfully slow - next time going to try synthesis from sodium hydroxide. Sodium acetate is actually a pretty interesting chemical as itself due to interesting phase transitions of it's hydrate - some day I will have some fun with it.
Picking solvent for reaction is another story: components are almost insoluble in water so we have to use some organic solvent. In DMSO (which worked nicely with Luminol) there was some aggressive side reaction. Ethyl acetate has extremely bad smell and is quite unsafe. One of the best and final picks was dibutyl phthalate.
This is not the end of my experiments with CPPO, I still have 99.5g left
Daylight astronomy - VenusIt is believed that city glow at night is a no-go for astronomy. But what about daylight?
I've managed to observe and photograph Venus at noon, when sun was at it's brightest. Without any reference points in the sky and without motorized mount - it's a challenge to spot Venus at daylight. In my binoculars (11x70, with ~4.5° FOV) it was taking couple of minutes using Stellarium and ground reference points.
After that - few more minutes to spot it using main telescope. Venus is no longer a thin sickle - after 3 months Venus and Earth have gone quite far apart on their orbits around the sun:
What's next? Mercury? That's gonna be slightly dangerous... :-)