Svarichevsky Mikhail - RSS feed Svarichevsky Mikhail - RSS feed en-us Tue, 10 Jun 2006 04:00:00 GMT Tue, 22 Aug 17 18:01:00 +0300 120 10 <![CDATA[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. 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

Tue, 15 Aug 17 03:40:56 +0300
<![CDATA[Daylight astronomy - Venus]]>
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... :-)]]>
Mon, 24 Jul 17 03:41:28 +0300
<![CDATA[Sun and AZ5]]> telescope is on a stable mount - TS AZ5:

Farewell photo of sun spot #2665 in Hβ (486.1nm). Solar minimum is almost there so we are not going to see lots of sunspots during the nearest years.

Sun, 16 Jul 17 16:02:43 +0300
<![CDATA[Fuming nitric acid synthesis]]> decomposition of lead(II) nitrate, then dissolving mix of liquid nitrous oxides in 68% nitric acid. This process was too scary to describe in detail

This time I went for conventional and relatively safer route: potassium nitrate (100g) + 98% sulfuric acid (125ml, ~50% excess). You can then distill nearly 100% pure nitric acid.

Final result was reached much easier and faster. Yield was 50ml (which is ~50%, had no more time and ice to continue the process). Next time I will ether have to try something more high-tech (like Peltier cooling with Liebig condenser - Graham's condenser seems to be an overkill and strictly speaking you cannot use it at this angle), or run the process at winter (but it's probably not a good idea to store >100ml of 100% nitric acid due to it's instability).

I've tried a bit of final product right away by etching Texas Instruments IC with very chemically durable plastic.

Conical flask with potassium nitrate and sulfuric acid with glued thermal probe:

It is hard to keep cooling water under 21°C at summer (so that remaining NO2 does not evaporate), so I had add ice blocks pre-cooled to -35°C from time to time:

Receiving flask also had to be cooled:

Here you can see that when Graham's condenser is installed at an angle liquid is trapped in the coils which causes non-continuous liquid flow - that is why it is not recommended to install condenser this way.

Wed, 05 Jul 17 00:46:04 +0300
<![CDATA[First light of Skywatcher 120ED refractor telescope - Moon and Saturn]]> my old 10" dobsonian it was almost pointless to observe from the balcony - air turbulence was extremely severe and leaving no chances to catch even single clean frame. That's another reminder than bigger is not always better.

In 120ED I haven't noticed chromatic aberrations yet - FPL-53 glass did it's job. Very happy that I did not went for triplet apochromat - it would have been much more sensitive to misadjustment and temperature changes. Also, diffraction-limited apochromats are rare beasts despite their hefty price.

On interferometric test this 120ED shows quite decent results. One can only complain about slightly teared first diffraction ring, but overall quality is well above "diffraction-limited" criteria (Strehl ratio of 0.948 >> 0.8):

First of all, let's take a look at Saturn, even though it's very low over horizon (just 12°, which is not making image better).

From left to right: Saturn via my good old Sony 500mm F8 catadioptric lens, then 10" dobsonian and on the right - this 120ED. One can already see Cassini Division but there is still room for improvement:

Moon could be compared to my best shoot via remote telescope, for example on Copernicus crater (93km in diameter). 120ED on the left, remote photo on the right:

Whole moon photo (clickable):

My first impressions are very positive. Now I just need to figure out what to do with telescope mount, on photo tripod it is currently extremely flimsy. Also motorized focusing should make it much easier to work with.
Mon, 05 Jun 17 03:28:34 +0300
<![CDATA[Venus and Saturn today]]>
Good old A77ii+Sony 500F8]]>
Tue, 18 Apr 17 05:54:03 +0300
<![CDATA[Upgrade time! LGA2011 FTW #2]]> LGA2011 with i7-3820 (4 cores, 32nm), not waiting for Ivy Bridge. Recently ebay got filled with lots of used server CPUs on LGA2011 which were compatible with my motherboard. That was extremely tempting and much more interesting than upgrading to yet another boring quad core system.

I went for E5-2695v2 - 12 cores, 30Mb of L3 cache, 22nm (Ivy Bridge). That is one of the largest commercial dies - enormous 492 mm².
This all currently costs mere 295$ (just 4 years ago Intel was charging whopping $2336 for that).

Task manager looks beautiful now:

Quick benchmark results: Surely, both old and new processors are overclocked. For E5-2695v2 overclocking is really limited by multiplier and BCLK. Stability is rock solid - I was even able to reduce core voltage quite a bit so temperatures under full load are unbelievably low for 12-core CPU (<50°C).

i7-3820 @4.3GhzE5-2695v2@2.926Ghz HT OnE5-2695v2@2.926Ghz HT Off
x264 ffmpeg, FPS5311388
Linx, GFLOPs95197.42201.2
Typically, on parallelized tasks it's >2 times faster. With this amount of cores it is no longer possible to ignore multicore support in all applications I use. I even had to upgrade some of my image processing scripts using mparallel.

Now I can work in peace until we'll get some dual-socket systems with 16-32 core CPUs and HBMs...]]>
Wed, 12 Apr 17 05:47:30 +0300
<![CDATA[A look inside Russian 28nm MIPS CPU - Baikal-T1]]> Baikal-T1 - Russian implementation of dual core Imagination Technologies MIPS P5600 32 r5 with on-board 10Gb Ethernet. Baikal was the first to implement P5600 core in silicon.

CPUs itself (had to go through 4 pieces to get a good die):

Read more on →]]>
Tue, 28 Feb 17 20:46:39 +0300
<![CDATA[Time for decent SDR: Ettus N210 - 40Mhz of RF bandwidth]]>
Although it is surreal to see 50Mhz of spectrum in realtime (40Mhz bandwidth using UBX-40 - 10-6000MHz RF frontend) - it is only available on the host in 8-bit mode (it already requires 800Mbit/s - using otw_format=sc8 in device string). In 14-bit ADC mode we can "only" fit 25Mhz through gigabit Ethernet. But if you're ready to do custom processing on internal FPGA - one can do better.

Ethernet connection is really useful - now I can easily set it away from the PC, for example on a balcony - where I already have Ethernet cabling. Also it will not pickup any noise from the ground as Ethernet is isolated.

Tue, 14 Feb 17 03:56:35 +0300
<![CDATA[Time]]> ]]> Sat, 21 Jan 17 23:54:31 +0300