Many times in the zany life of the inveterate tinkerer I find that the solution to a problem is at hand in the bits and pieces lying around the shop (or more likely, my desk). I was looking at a cigarette adapter that came from a cellphone (or something) wondering what use it could be before relegating it to the special waste box.
This paper is a discussion of hardware, software, methods and actions that a newcomer might find useful. It is not meant to be an in-depth discussion of all forms of astro-photography; that would take many books and more knowledge than I have available. But I hope that my descriptions and graphics will help a newcomer to the art understand a bit more what is involved in this wonderful pastime.
Focusing can be a chore at times and if you are one of the practitioners of the arcane art of astro-photography achieving the best focus possible is critical.
In a previous article I talked about building a simple variable-speed controller for a DC focus motor. In this article I’ll show how I put that controller to use on my recently purchased AstroTech 8” f/4 Imaging Newtonian.
SCT’s generally keep their collimation quite well if not mistreated but there will come a time in every SCT owner’s life that they have to re-align their secondary mirror. Here is a simple and effective way to do it that won’t cost you hundreds in fancy equipment.
A few of the habitues of Fingal have, after looking at my setup, called what I have out there ‘Rick’s World of Wires’. This is due to the large number of cables that lead to, or are strung over and around, my telescope mount.
One of the most electrical common needs of an astronomer in the field these days is some way of creating numerous small DC voltages from one big one. The most frequently used source being a 12V marine or automotive battery. The smaller voltages could be anything from 5 to 9 volts and are used to power a hub, a camera etc.. Fortunately, there is a family of step-down voltage regulators that are very inexpensive and easy to work with that can provide what you need. These are the 7800 series 3-lead positive voltage regulators.
Over the past few years I have plied my trade as an imager with a few low and medium priced refractors for wide angle imaging and an old Celestron C8 SCT for longer focal length work. The C8, while having very nice optics for its type, just wasn’t giving me the images that I wanted so it was time for a change.
Telescopes that are hauled across the landscape to observing sites away from home get out of alignment, or collimation. Getting things back in order is part of the job of observing. Some telescopes such as Maksutov-Cassegrains with a silvered secondary and refractors tend to keep collimation almost forever (unless mistreated). Other types need to be checked and adjusted sometimes every time that they are used. This little paper will discusss Newtonian type reflectors.
When I arrived in Indiana on my last trip down there I found that I had left my Hotech SCA collimating laser at home. As Doug didn’t have a functioning laser on hand I had to improvise.
There comes a time when it’s good to reduce the number of wires and boxes that are hanging around your mount. I’ve always used a DC/DC adapter to convert 12V down to 8V for my DSLR and another to convert 12V to 5V for my 4-port USB hub. Finally I decided that enough was enough and merged the two into a single small unit.
Any observer knows that dew can quickly put an end to a promising evening, or at least force an intermission as hair dryers are used to dry off fogged optics. In addition, dew may also carry harmful airborne chemicals which attack mirror coatings. While the Kendrick Dew Remover system is very popular, many home brew astronomers and ATM’s might want to make their own Dew Preventer.
My imaging sessions see me in the field using a ‘PC’less’ setup This is not completely true as I do at times carry a netbook to aid in alignment and focusing; but this is only to expand my camera’s LiveView output from the small on-camera LCD to a 10.1 inch display. This could be done as simply with my small 12v black and white TV but the netbook draws less power and is smaller.
Barely a day goes by without someone asking on an astronomy forum “which equatorial mount should I buy” and naively expecting a definitive answer. Most are disappointed to hear ‘It depends’. There are many mounts on the market these days and no single offering is the best one for all circumstances.