Galileo's Camera

About a week back, the NexStar 4SE that I ordered arrived. I've been quite eager to test it out in the field but however so far been unsuccessful due to bad weather. But the first impressions so far have been good. Here's a short review on the 4SE compared to the 114EQ. Out of the box: Everything was neatly packed in one single box. Assembling the telescope was very easy, the entire set was only four pieces or so. There is no way you could get it wrong. The batteries for the controller of the telescope are not included (8 AA batteries). The battery for the spotting scope (CR2032) was included, but had already drained. Tripod Assembly: The tripod mount of the 4SE is made out of steel. This is not a major change from the tripod of the 114EQ, but does differ in one aspect. The feet/base of the tripod of the 4SE consists of rubber bushes instead of the plastic base of 114EQ. This somewhat absorbs vibrations and would allow a better photographic experience. The plastic moun...

About two weeks ago I finally got my hands on the motor drive for my Astromaster 114EQ. I was debating whether I really need it or not and finally decided to just go for it. And over the weekend I had it installed and tested. To start off with, the motor drive arrived with minimal instructions. But that wasn't really a problem. The product was quite well made that I was quite intrigued by the whole design. Granted, it wasn't very intuitive, but the instruction sheet was quite to the point, that it was quite impossible to screw it up. It even had an Allen key and a screwdriver that fits the relevant bolts. But this doesn't mean that everything was going smooth. Once I fitted the mounting bracket, I figured that the coupler between the motor and the scope wouldn't fit on to the RA shaft (Celestron refers to this as the flexible coupler). The inner diameter of the coupler is almost exactly the same size as the shaft. I was about to file it off when I figured that I had...

In the last post, I wrote about what is collimation and what sort of an effect a non-collimated telescope has on imaging. Taking it from there, let's see what are the equipment we can use in collimating a telescope. No-Tools: Firstly let's ask the question whether we can collimate a telescope without almost any tool. It is possible for someone with real good patience and a reasonable eye-sight could collimate a telescope that is not seriously misaligned just by star-light (point at a star, keep adjusting up until the slightly out of focus image stops being an ellipse and becomes a disc). However using a collimation cap makes the job much more easier. It is not necessary to collimate the telescope during the night when using this method. It is possible to perform daytime collimation by center-spotting your primary mirror. What is center-spotting? It simply means marking the exact center of the primary mirror. Some of the telescopes come with the center marked from the factor...

For any reflecting telescope, collimation of the optics is one of the most important and regular tasks. Collimation simply refers to aligning the primary mirror and the secondary mirror along with the eye-piece. However, the job it self is not that simple. If a telescope is not collimated, the image it creates would not be in the same plane as the eye or the projection plane (in case of a camera/ccd/projector is used). This could lead to various ring patterns, distortion of the image to appear when viewed. This means that even when you have focused the image properly (or brought the viewing plane up to the focal point), the image is still not clear/smeared. Fortunately, this it self provides an easy way of identifying whether or not a telescope is properly aligned. Ray diagram of an uncollimated Newtonian - Red line depicts the plane where the image is created. The green line depicts the viewing plane. To try to understand what happens in an uncollimated telescope, let's ...

For anyone who wants to get in to astrophotography, one of the obvious first questions is "How do I connect my camera to the telescope?". Well Celestron has an instructional video on how to. The 10min video covers all types of mounting/connecting methods like A-focal (mostly used with point and shoot cams), prime focus (used with DSLRs), web cam astrophotography, CCD based photography and  piggybacking. Of course, it is a promotional video from Celestron, so obviously they promote Celestron products, but it is a good start :)