In 2005 we moved to the north shore of Mantrap Lake in Minnesota where the skies are very dark. Even my elderly eyes see a zenith limiting magnitude of about 6.75 though younger eyes have reported 7.25. The township I live in has 31 residents in 36 square miles many leave for the winter. What lights there are, are hidden below a mostly pine forest canopy. Much of the area is uninhabited state forest or in non-revocable trusts that prevent development. Not one cabin or residence can be seen from my location though I can see for several miles around the lake. I’d been coming to this lake since 1949 so know the area well. I owned a cabin on a different part of the lake for 36 years but it was unsuitable for a residence let alone an observatory.
Since I wanted it for both imaging with a dedicated imaging system and visual with my 10″ f/5 it is a roll-off roof design rather than a dome. Since ground seeing effects can be a problem down near the lake it is built atop a 44 foot hill. To further reduce ground effects the telescope is about 16 feet above ground level so about 60 feet above lake level. Access is via an upper-level deck from the house. No access from the ground to help limit visits from north woods critters. Stairs from the second level deck lead to the observatory. The pier is reinforced concrete 20 feet tall, of which 6 feet is below ground level and part of an 8’x10’x6″ slab. The hole was backfilled and tamped down. This keeps the base below frost level. A 2′ steel pier sits atop the concrete pier and the Paramount on that. The area below the observatory is storage for hoses, mowers and other things that can survive the cold. It also has water and is my fish cleaning house. A 12′ ceiling leaves lots of room for storage shelves. Of course, the pier is an obstacle you work around. It is still covered with the fiberglass culvert that acted as the form when it was poured. It is softer than bare concrete when you forget and bump into it. Not so soft is the 5′ 6″ door to the observatory. It is short to allow the scope to reach as low as possible to the horizon. After seeing stars in the daytime I finally learned to duck. I rarely go out there anymore so it’s not much of an issue.
The track design had to be different with the track 16′ above ground level. Looking for a source for the track a potato processing plant 25 miles to the south had just been awarded a contract to provide french fries for much of the US but had to throw out its steel system for moving potatoes with one that was stainless steel or aluminum. This created a huge scrap iron pile I was able to utilize at scrap iron prices saving a huge cost. The track base is made from rollers used to move heavy loads of potatoes. The roof’s track is just steel I-beam they had to discard. It also serves to support the roof itself. The rollers carry much less weight than they did moving potatoes. In fact, the roof will roll with ease even when covered with a foot of snow needing less than one pound of pressure. I rigged a junked garage door opener to roll the roof and rewired the IR beam so that it worked in both directions. The beam reflects off a second surface mirror glued to the back of the scope. The beam reflects into the receiver only when the scope is parked. This system prevents the roof from moving when the scope could be hit. Twice it has saved me from this foolish move. Both times I stormed out to the observatory, once in -35 weather, mad the roof wouldn’t move until I saw the scope still pointed up. I highly recommend some sort of system to prevent such mental lapses.
I finished it in the spring of 2006, my wife insisted the house came first so we could move out of the basement or it would have been done earlier. I’d planned on it long before the move. Several years earlier Software Bisque announced the Paramount ME mount which a couple professional astronomers I knew recommended highly. I’d been saving for a new mount and its then $9500 price was barely doable so I ordered it only to find it back ordered a year from all dealers. Apparently, some orders vanished as it came in 8 months, a couple years before moving here so there it sat in the garage. After considering all sorts of options and checking out the seeing at the location we were moving to (I’d bought the lot several years earlier) I decided on the Meade 14″ LX200R (now ACF) optical tube. At the time that was the largest aperture reasonably flat field scope on the market, I could afford. RC scopes were way out of my price range at the time and the Celestron HD line was years in the future as were modified D-K scopes and less expensive RC scopes. I bought a used STL-11000XM with Astrodon filters at an attractive price (well below the new cost of the camera alone). All have served me well for over 12 years now.
Due to Minnesota summer nights full of “voracious, long-billed, dyspeptic mosquitoes” and winter temperatures of -40 not uncommon I knew it had to be run “remotely” from the house. Though when I first started using that ancient 6″ f/4 on the Paramount ME (the LX200R was back ordered for longer than the Paramount ME) it was spring before the mosquitoes so I ran with a laptop in the observatory. That was a disaster for the laptop. Midge flies don’t bite but they cover computer screens attracted to the light. They live only hours, much like the larger mayfly. They soon die, fall from the screen and into the keyboard. In only a couple hours the keyboard was dead due to squished midge flies. Three days later UPS brought a new keyboard. In the meantime, I hurried the moving to inside the house. After a bit of debugging, I could do most things inside but still had to go out with the laptop from time to time. Several such visits killed yet another keyboard to those midge flies. By then I could do everything that needed the computer from inside. It wasn’t until 2008 that I never needed to go into the observatory for something — I still need to clean off cobwebs from the front of the dew shield and do annual maintenance.
For the first couple years, I was working in ignorance and had some very wrong ideas about how to take digital images (I’d only used film) and processing the data. Most of those first objects have not been retaken and only a few have been reprocessed. So you will see a wide range of image quality while at this site.
My main interest isn’t pretty pictures though sometimes they happen. Taking an image is usually just an excuse to research the object. Thus, I don’t spend much time on major objects. I’m more interested in the rarely seen and in pushing the envelope of what an amateur can do with today’s equipment. With over 1500 different objects taken developing this site will take time. I’m starting with the Arp galaxies I could catch from 47 north latitude. I’ll be adding over 1000 other objects as time allows. The Internet is slow here so it is slow going and I’m still taking and researching over 100 new objects a year.
For more on the images found here see the page on observatory images.