Ring of Fire - ASE '10

Eight members of the COEP Astronomy Club (along with three members of a local Astronomy group - 'Akashmitra') had gone to Rameshwaram, a coastal village in South India to catch the Annular Solar Eclipse of 15th Jan 2010. Rameshwaram was chosen for its proximity to the Central Line of Eclipse (central line of the belt of shadow; places lying on this line have the longest time of eclipse and the maximum phase, with respect to places lying on a line perpendicular to the central line at that point).

In all, the long journey (around 30 hours one way!) was very much worth the 8-10 minutes of annular phase and 3-4 hours of the entire eclipse.

Click here (web album) for remaining photos of the event by the author.

One Pledge

Over a billion of us - one Pledge
An oath taken countless times
An oath not all remember
India is my country

One rightful haven
Unlike the less fortunate
Who still struggle
To call a place home

We ridicule the system
But at least there's one in place
We cry for luxuries
But at least the basics are in place

Education we crib about
The very same that taught us to compare
We run around for petty things
But at least not for our lives

Our voice is not heard we say
But at least we can raise it
Nothing's going to change we declare
But at least we have the chance to try

India is my country

-abhi

DIY Shutter Release Cable

Since the time I've been trying my hand at astrophotography, I've felt the need to have a shutter release cable. These relatively simple cables sell for anything between $20 to $100 (and probably even more!) online depending upon whether you want to have just a plain 'auto-focus and shutter release' function, all the way up to ones with digital intervalometrs and time lapse options.

However, luckily my camera (Canon 350D or popularly known as Digital Rebel XT) features a 2.5 mm audio female socket for plugging in the shutter release cable. Below are steps with photos describing how to make the simplest cable, inspired by many others who have made similar ones.

1)

You'll need one switch (the red one above is called a rocker switch), one spring switch (the black switch in the photo with a square head), one 2.5 mm stereo audio male connector (in the photo above the black sleeve has been removed to expose the metallic pins behind the connector), a plastic box to house the switches, some wire (depending on how long you intend to make the cable) and a hobby knife (or a swiss knife).

2)

Cut a slot in the lid of the box such that the rocker switch fits in snugly. I preferred to place it horizontally (if the box is held like a TV remote) but you can place it anyhow.

3)

To make the plug that connects to the camera, you need to keep in mind the following-

a) the longest pin is the 'common pin'

b) the shortest pin is the 'full depress pin'

c) the medium pin is the 'half depress pin'

So to just auto-focus (i.e. half depress the shutter button) you need to connect the medium pin with the common pin. To release the shutter (i.e. full depress the shutter button) you need to connect the shortest pin with the common pin.

Now since I'm going to use the cable release mainly when long exposures on 'bulb' mode are called for, I decided to use a toggle switch for the shutter release. Also since auto-focus is rarely required in astrophotography, I've not provided a corresponding switch for that. However, if you wish to provide an auto-focus switch as well, simply connect a third wire to the medium pin and through the spring switch connect it to the common wire.

Remember to wrap insulation tape after connecting the wires to the pins.

4)

So coming back to our cable, once you connect the appropriate wires, put the sleeve back on the connector. Tape the wires to the sleeve as shown to prevent them from snapping off inside the sleeve.

5)

Connect the other ends of the wires to the switch and wrap insulation tape. Now guide the wires as shown and tape them up; this is to prevent accidental snap off as for the connector wires.

Also make a small cut in the box for the wire to come out through, when the lid is closed.

6)

Looks cool!

7)

The best part is, the wires can be just folded and placed inside the box for a neat and compact look!

PS: Taking orders for the above if you don't have the time to make one or are just plain lazy! lol!