My Evening With John Dobson

I am one of the fortunate amateur astronomers in this world who had the chance to meet and spend some observing time with the man whose name is synonymous with the Dobsonian telescope.

I was 22 years old at the time, and it was the summer of 1985. Please forgive me if I have my dates wrong since it was 25 years ago, but it was either on Saturday August 3rd or Sunday August 4th of that year. I grew up in the small town of Elkwater in the Cypress Hills Provincial Park in Alberta, Canada. During that summer, Alberta Culture and Recreation had hired John to do a number of shows at various provincial parks in the province, and ours was one of them. I had a good interest in astronomy by this time and had spent a fair bit of time under the stars myself. This was at a period of time before John had become the legend that he is today. The only Dobsonian telescopes around in those days were the ones that people had made themselves, there was very little commercial production, or at least, nothing like there is today. The magazines Astronomy and Sky and Telescope were just starting to warm up to the idea of the "Dobsonian mount" as a viable model for a large aperture instrument with some easy to use characteristics and features.

During the late afternoon, John took his van down on the field and unloaded his sky canon. This was his smaller model telescope, it housed an 18 inch mirror, and it was huge. It was clearly the largest telescope that I had ever seen in my lifetime up to that point.

As darkness began to descend on the park, John took the stage at the amphiteatre, and gave a brief talk and showed some slides. One of the first things I noticed about him was that he had an eccentric turn to him, he just struck me as someone unlike anyone I had ever met in my life. Of course his background, being born in Beijing, spending years in the monastary, and holding a degree in Chemistry is a pretty unusual combination to begin with.

The evening weather was less than perfect. But just as he finished we got a break from the clouds, and a core group of people walked on down to the scope in the field, where as kids, we used to play baseball. There were maybe 10 people. John pointed his instrument at M57, and one by one people ascended the tall ladder to glance at the Ring Nebula. I was treated to a view unlike anything I had ever seen before. There was no disputing what we were looking at. And clouds came and went and gradually people drifted away and returned to their campsites, but I stayed. I spoke with him a bit about the construction of this rather crude looking instrument that resembled a gun canon from a war ship more than a telescope. We had a chance to view a couple of more objects, M27 and M71 and they were equally breathtaking. At the end of the evening I helped him to remove the scope from its mount and load it in the van, shook his hand and thanked him very much for the chance to look through this large scope.

I had no idea at the time of the legend of a man I was meeting, but I knew that I wanted to keep doing astronomy. Within two weeks I had bought my first real camera for doing astrophotography, and started to build the base for a domed observatory to house my 6 inch scope, which I never completed. Within two months I was on my way to pick up my Cave 10 inch scope, and the following summer I built my roll off roof observatory. I really think that hour or two I spent with John Dobson convinced me that this was a valid and fantastic hobby. And if I was into this hobby before then, that time we spent together put me in with both feet and my face to the fire.

Upgraded Powertank

I went ahead and added a 400 watt inverter to my power box in order to accomodate my laptops. I am going to run a pair of laptops, one older one with an RS-232 serial port for guiding and a newer one that has considerably better battery life for running my camera with BackyardEOS.

I added a 105 amp hour marine deep cycle to the case at the same time. Walmart now sells only the hybrid deep cycle but this unit delivers almost 25 additional amp hours over their old deep cycle battery and I have a 3 stage battery charger to keep it properly conditioned. I think this should be enough to power all of my needs for an evening.

And if not, I have other options. I can use the battery pack for the telescope in an emergency, or get a second battery box and gang it alongside this unit in parallel and double my capacity.

Rescuing an Orphan

I had this Meade Telestar telescope given to me several months ago, it was headed for the trash can. It had one broken leg and was missing several components including eyepieces, the eyepiece to the finder scope, bolts for the accessory tray and the Autostar controller.

I brought the OTA in the house the same day I got it and set it in my telescope den. The mount stayed in my car up until last week when I finally decided to get it out of there and see if I could repair it to get this OTA up off the floor. Honestly I had written the mount off and was intending to build a Dobsonian mount for this scope.

I had never paid attention to the aperture of this scope, I guess I just assumed it was a 4.25" reflector, but the specs came out that it is a 5.1" f/7.9 OTA, and the included 25mm eyepiece leaves it right around 40x, which is one of my sweet spots for observing. I also found in my "extras" collection that I had 3 additonal 0.965 OD eyepieces that I could use with this scope that I got from an old discarded refractor that has since gone to telescope heaven. Since this is almost an f/8 they should work fine with it.

Upon examing the mount, I found that I could use some machine screws to repair the tripod leg. A good tightening of all the existing bolts and screws added some rigidity to the mount. In my "extras" collection I had a base for an MRRD finder from one I had ordered from Agena two years ago that was not being used. I removed the stock finder and rings and filled in the screw holes and mounted the new base and took the finder off my binoculars and installed and aligned it. I left the accessory tray off of it for now as it is awkward and not really well thought out.

All of the repairs have given me a decent little visual scope on an alt-azimuth mount that I can use manually for the time being. It will make a nice addition to my evenings when I am imaging with my Schmidt Newtonian and it has more aperture than my binoculars or my ST-80. It also makes a nice little grab and go because I can carry the entire assembly out the door without taking it apart. I am going to look for an Autostar controller for it and see if the motors are still functional, but even if they are not, I am perfectly content to use it in manual mode. I enjoyed refurbishing this scope and soon I will know how it performs.

A Beginner Astrophotography Bundle

Let's say you are interested in learning the ins and outs of doing some very basic attempts at sky shots, but you don't want to spend a whole lot of money right up. Perhaps you are primarily a visual observer who owns a Dobsonian telescope but has a passing interest in learning astrophotography without starting at the top of the price curve. At $159, the Orion Adventures in Astrophotography Bundle is an excellent concept and a simple product that will allow you to take your DSLR (or 35mm camera) and crank out some excellent wide field results.

I have built a setup similar to this using my LXD 75, a dovetail and the exact same camera mounting bracket shown in this picture for doing much the same thing. Using this is very simple, you simply align the polar axis of this mount to polaris, install your camera (with remote) to the mount and point it, turn on the tracking, wait about one minute and begin shooting. A setup like this can be imaging with your camera on an undisturbed mount for hours at a time while you casually browse the universe with your primary telescope. This device would be excellent for recording things like meteor showers, making a large view of the milky way, comet photography, or anything else that lends itself to some interesting wide field shots.

Personally I love doing wide field astrophotography and have been doing it for years. It is highly forgiving on polar alignment, generally does not require guiding (merely tracking) and can produce some really stunning results that do not require a tremendous amount of effort or setup time. If you have purchased this bundle, I would enjoy hearing from you.

Planetary Observations

One of the simplest things for a beginner to enjoy are the views offered through a telescope of the planets. Jupiter and Saturn are two of the most amazing sights many first timers will ever experience in a telescope, and a quick trip with Google will help you in locating their positions in the night sky. Venus, Mars, Jupiter and Saturn are all fairly easy to spot as they tend to be brighter than the stars around them at various points of their apparitions. Viewing the outer planets is best done when the planet is at opposition (planet rises as the sun sets) as it crosses near the meridian, an imaginary line that transits from due north to due south, directly overhead, which happens generally between midnight and 1 AM.

Planetary viewing requires patience, good seeing, and on those nights of exceptional seeing when you can pour on the magnification, you will be rewarded with amazing details in your observations. Aperture is king here. Telescopes can generally handle up to a maximum of 60 times magnification per inch of aperture in theory, but often the atmosphere will forbid much above 150x on most nights. Still when you hit those special nights of exceptional clarity and pour it on, you will be amazed.


A selection of filters can help in your viewing of details as filters allow transmission of only specific wavelengths and will block others to enhance the contrast of many details like ring divisions, belts, spots and caps. Most any astro retailer will sell a basic set of planetary filters to help get you started, but this chart located at the bottom of the page gives some very good information on specialized filters for specific needs.

As with anything visual, experience will help you a lot here. Getting out and looking at the planets with a variety of instruments helps you to learn to train your eye to see things that most would simply pass over, and it gives you a reference for what to expect during your oberving sessions. Good luck and get out and enjoy, soon Jupiter will be up in the evening and this is an excellent place to begin and learn.

I'm not collecting dust

It's been so long since I have made an entry on here I thought I might jot down a few words about what's been going on. I have taken a bit of time off to re-focus on things and have put my hobby on hold a bit, but lately I have been finding myself drawn back again. Something about the warm weather and the fact that I have made some progress on other things around me and my telescope pad has been sitting there looking at me wondering when it will get some use.

So the next clear and moonless night I am planning on digging my gear out for a night of great astronomy and some astrophotography. I have not even tried out my new autoguider yet so there is plenty to do and now that the weather is warm, it is time to get back to the hobby that I love and admire so much. My telescope is home and this is where it will stay. This weekend I will complete organizing my astronomy den, check over my gear, hang some astrophotos, and spend some time with some books. The healing is complete. Clear skies to all of you.