Sanya Rajan A compendium of stuff

10Sep/120

Bhut Jolokia

 

I ordered some Bhut Jolokia seeds and dried pods a week ago and they arrived today. The Bhut Jolokia is currently ranked as the second hottest chilli pepper in the world, the hottest being the Trinidad Moruga Scorpion.

It arrived in a cloth bag with the peppers wrapped in a plastic bag inside that.

I tried eating a piece of one of the pods, these are HOT. I've got a packet of seeds as well, so I'll try growing them. The next step is to get hold of some Moruga Scorpion chillies.

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28Aug/121

Get a custom redirect to your Google+ profile

 

Google has recently started rolling out custom URLs for Google+ profiles. However, at the moment they are rolling them out only to verified users and big brands, and also in their TOS, they state that they have the right to reclaim them or remove them without notice and also charge for them in future (http://www.google.com/+/policy/tos-custom-url.html).

I like Google+ and have met lots of cool people from around the world on it, and it is becoming more popular every day. Eventually, I might get an invite to get a custom URL, but I prefer to have a bit more control over it. Therefore, I decided to redirect sanyarajan.com/+ to my Google+ profile.

If you want to do this just add the following lines to the .htaccess file in the root of your website (replace the profile URL with your own):

# BEGIN Google+ redirect
Redirect /+ https://plus.google.com/104684298309471385021/
# END Google+ redirect

 

You can also use this to redirect to your pages, just replace /+ with /+PageName and change the URL to the one for the page.

21Jul/120

Onion skin cells and an ant’s eye

 

I finally got around to using my microscope again. This time I observed some onion skin cells by taking the inner layer from a piece of onion and staining it with Lugol’s iodine. I took the picture below using my cell phone camera pointed down the eyepiece.

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I also took a look at an ant’s eye; in the picture below you can clearly see the lenses of the compound eye and part of the ant’s leg.

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12Jul/120

Olympus CX22LED Unboxing

 

I ordered an Olympus CX22LED microscope a few months age and it finally arrived today. It is a biological microscope with a binocular observation tube and four objectives (4x, 10x, 40x and 100x oil immersion). I took a few photos of the unboxing.

These are the accessories that came with it, the power cable (I had to attach a plug), the darkfield ring and the dust cover. I discovered that to use the darkfield ring I would also need a filter holder, which I unfortunately, did not order.
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The main box the scope came in, and what it looks like when first opened.
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The instruction manual and unpacking guide that was on top.
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The bottle of immersion oil and the power adapter.
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The packed microscope in the box.
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The scope with the retaining bands and protective tape.
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With the tape removed and the eyepiece rotated to the correct orientation.
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There were a couple of places where the tape left some residue on the XY-stage controls and the side of the stage, I had to clean it up with some alcohol.
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Switched on.
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In the dust cover and in the protective wooden box.
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I will post some pictures of what I can observe through it once I figure out a good way to take the pictures.

5Jun/120

PC Control Cable for Celestron NexStar Telescope

 

Since I was getting my telescope ready to view the transit of Venus on the 6th of June, I decided to build a PC control cable for it so that I could control it through a program like Stellarium.

I followed the schematics on Michael Swanson’s NexStar Resource Site (http://www.nexstarsite.com/PCControl/RS232Cable.htm). My telescope is a NexStar 130 SLT, and the control cable connects to the base of the hand control and connects to the PC via a serial port. The parts I used are shown below.

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I used a telephone handset cable (far right) to connect to the base, an RJ-22 socket and a female DB-9 adapter and housing.

I wanted to put as much as I could into the DB-9 housing, so the first step was to trim the bottom of the housing so that I could glue the RJ-22 socket into it.

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The only tool I had to do this was a hacksaw blade, so the cuts look a bit rough, but it was good enough for my purposes.

The next step was to solder the wires from the RJ-22 socket to the DB-9 adapter; following the schematic on the NexStar resource site. One thing I picked up is that the wiring in the telephone handset cable is reversed, so pin 1 on one end connects to pin 4 on the other.

It’s been a few years since I used a soldering iron and the lack of practice shows. I melted the plastic on the back of the adapter a bit when trying to remove some solder that had dropped in between a few of the pins. The RJ-22 socket fits in the gap I cut at the back of the housing.

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But with everything put together it looked quite decent. Here are a couple of front and rear shots:

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The finished cable:

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The extra screws are parts of the DB-9 housing I didn’t use and the screwdriver is what I resorted to in order to dig out solder that had gotten embedded in the back of the adapter.

The cable works well, I had to use a USB to RS-232 adapter to connect it to my laptop. I’ve used it to update the hand control and motor control firmwares and I can select an object in Stellarium and have the telescope automatically slew to it and track it.

Since I bought all the parts in India the total cost (including buying a soldering iron) was about Rs. 500 (~$8.2).

27Apr/120

The shadow on Saturn’s ring

 

There was a post recently on Futility Closet about the shadow Saturn casts on it’s ring appearing to curve away from the disc. (http://www.futilitycloset.com/2012/04/26/curve-ball/)

[…], I found the shadow of the globe on the rings curved the wrong way, i.e. from the globe, as shown in the following drawing.

http://books.google.com/books?id=y6oRAAAAYAAJ&printsec=frontcover#v=onepage&q&f=false

[…] Professor Comstock also adds, ‘I do not know that any satisfactory explanation for this anomaly has ever been given.’

The explanation of this illusion is quite simple, it is caused by the perspective of the viewer in relation to how the shadow is being cast. The photo below taken by Voyager 2 shows a much clearer view of the shadow. The shadow appears to curve away from the disc, but when you consider that the sun is shining from the bottom left the shadow being cast is actually directly behind the planet and it’s just our perspective that makes it seem like the shadow curves the wrong way.

Image source: http://voyager.jpl.nasa.gov/image/saturn.html

25Apr/120

Salted frog legs rag

 

Frog legs twitch when you add salt. Here’s a video I made, set to Frog Legs Rag.

Salted frog legs rag

Source video: http://www.youtube.com/watch?v=2YZJt_Bw3eo

Why does this happen?

Short answer

The salt activates random nerve cells and they send signals to the muscles causing them to contract.

Long answer

Nerve cells have a slight negative charge on the inside, when salt is introduced some sodium channels in the nerve cells open and allow sodium ions (carrying a positive charge) into the cell and depolarizes a local area of the cell membrane.

More sodium channels open and it triggers an action potential (nerve signal) and the nerve cell now has a positive charge on the inside (in that area), when the electrical potential reaches about +40mV the sodium channels shut down. The positive potential causes potassium channels to open and potassium ions move out, making the inside of the cell more negative. This outward movement of potassium ions causes the cell’s membrane to return to normal and the potassium channels close.

This depolarisation and repolarisation of a local region of the cell membrane gets passed along the axon of the nerve cell and on to the next until it gets to the muscle, which triggers a contraction. There is a short period during which an area that has been been repolarised cannot be depolarised (refractory period), this keeps the action potential moving forward.

Most poisons and pain medications work by preventing the channels that allow the transfer of ions from opening and closing, thus distorting or blocking the action potential. Since the size of the action potential does not vary, the information is coded by the frequency of the action potential. In the case of the salted frog legs only some nerves are activated at random and the frequency of action potentials is low, which is why the legs only twitch slightly.

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21Apr/123

The Pulfrich Effect

 

I was going though some old stuff that had been packed away and came across these:

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It’s a pair of 3D glasses that were distributed along with the Sunday Times paper, in South Africa, during the 2000 Olympic games. Some of you might recognise the SABC3 logo from back then.

The glasses are not anaglyph, instead they employ the Pulfrich effect to produce a “3D” image. The effect is induced by having a dark filter over one eye; in the case of these glasses, the right eye.

The darker image takes the brain slightly longer to process and so the brain is tricked into seeing a change in depth when an object moves from left to right across the field of view. The broadcasts made in 2000 had the most motion occurring from left to right.

A simple way to experience the effect is to place one lens of a pair of dark sunglasses over your left eye (hold them sideways) and watch the video below.

Demonstration of the Pulfrich effect
13Apr/120

Extreme camping

 

Now this is a camp site with a view.

image

Source: telegraph.co.uk

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12Apr/120

Morskoy Boi

 

Here is a site where you can play a replica of an old Russian arcade game Morskoy Boy.

You control a submarine and have to shoot torpedoes at ships on the horizon.

The title screen:
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The game play:
image

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