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23 February 2012

Ast. #4: About a new (literally) toy

Budget telescope with a homemade mount

It has been some time since I posted anything on this blog.. and lets get to business - no point spending time on lengthy apologizes when we could need the space (pun intended) for "snap n' tell"!

So I have bought myself a really cheap Newtonian telescope online. (at MYR150, that is equivalent to about 50 USD) Now I understand with such budget I didn't expect much from my telescope because I think it is literally a toy. Obviously the eyepieces are made of rather cheap plastics and lets not bother to talk about the corrections in chromatic aberration.

About few months ago when I received the package, the fragile (or rather futile) mount broke on first attempt of operation, so the telescope was left useless until fortunately me and my dad made an Alt-Azimuth mount in his workshop. So after that new mount, the telescope is good to go for eye observations (using the eyepiece of course) but definitely without less difficulty in making a suitable digital image capturing contraption - because seeing with our naked eye is just not enough. With a digital camera capturing the image on the telescope it will ease observations and here are a few reasons why:

1. You don't need to hand-draw the things you see with eye. Hand-drawn observations are prone to error.

2. By knowing the dimensions (size) of the camera image detector, we can do simple measurements on the image which can give us information on the size, rotation period, orbital eccentricity, and other physical property of planets, the moon and the sun.

3. A digital camera installed with controllable shutter (slower shutter speed) or detector sensitivity (high ISO) can capture more light in one exposure compared to the human eye. So, dim objects such as nebula and distant planets can be captured by the camera which human eye cannot see.

4. The photos taken by a camera with high resolution (i.e. high pixel count in a given image detector size) might be able to resolve small image given the image capturing conditions are right.

And many more advantages still to be listed..

So, I spend most of the time during my last month of semester break mostly finding solutions for prime focus photography. At first the focal length was too short to form an image for prime focus imaging, until I made a Barlow lens to extend the focal length into the image detector of my Nikon D5000. I have yet to make a tool to lock my DSLR with the Barlow lens so that stable photography can take place. (now the pictures are taken by hand-holding the camera to the Barlow lens)

In addition to a DSLR, I have a cheaper webcam which I have removed its lens, converting the webcam to a USB prime focus imaging device. The webcam can also take videos so I can video-record the observations I made (there are practical application why recording video is important, will got to that later..)

Anyway, that was the summary about my telescope system. Will update on the snippets of use soon!

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