Galileo's Camera

About a month or so back I realised that there is another problem with the 4SE, it wouldn't power up. Firstly I thought this was due to a battery drain, and that's the first thing I tried. While it worked once, after about half an hour of sky watching it stopped working again. It is quite improbable for a new set of batteries to drain that fast. After hooking up with a 12V 2A power supply, it still did not power up. This could mean two things: the power doesn't get to the circuitry or the circuitry it self is busted. After playing around a bit with a multimeter, the fault turns out to be... again on the switch . I think it is fair to assume that the part that has most physical/mechanical movement will be the first to fail. It is true that the electronics could fail, but I guess it is better to start from the switches. For the moment, I have bypassed the switch, and all is well (well except for the weather...)

During a failed attempt to observe and photograph the Camelopardalids meteor shower, I found out that the finderscope of the 4SE was not working. If you have not done this, try doing it, it is ridiculously hard to successfully aim the telescope at anything if your finderscope is not working. After testing with multiple batteries, my immediate worry was that the LED in the finderscope may have burnt out. If this was the case it would be quite hard to fix it. That's when I decided to dismantle the finderscope to pinpoint what exactly went wrong. Removing the finderscope from the telescope is quite easy. You need to unscrew the two bolts on the side of the finderscope, just under the switch and the calibration screws. Once done, you need to remove the unscrew the calibration screws themselves. You need to hold the calibration screw with one hand and unscrew the bolt. The calibration screw will otherwise turn along with the bolt. And this is what the inside look...

So yeah, managed to mend it DIY way, it does not look so great but well it still works. So here's what happened: I was trying to shoot Sirius around mid night and was dead tired. Was scrambling around half a sleep and toppled the telescope over. Had this been on grass, this would've been fine but it fell over and hit a tiled ledge on the balcony. Saw a piece coming off and my immediate thought was that its the bracket that went off. It wasn't the bracket, it was the mount. The only option I could think of was to write to Celestron  and see if I could purchase a replacement part. Unfortunately they didn't have any. They did confirm however that if I were to speak to one of their retailers, I might have a very small chance of finding one. Few emails later I figured that this is also not a possibility and the options I have are to purchase a new tripod-mount (i.e. the entire set), a new telescope or try to somehow mend it my self. With the PANSTARRS ...

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 ...