Observatory: Furnishing and accomodation.

 *

 Using the observatory usefully is now beginning to fall into logical place. The options are really surprisingly limited: Which I had not foreseen.

The telescopes are usually looking upwards from east to west via south. This sets limitations on which areas of the dome are useful and those which are [usually] not. The focuser end of the telescopes sweeps the northern half of the observatory at heights from horizontal and on downwards to the pier as the instruments point higher. At the moment the planets, Sun and Moon are all very low. This will change over time but tends to dominate how the observatory is used.

I do need to make some major changes to my equipment storage now I have a functional observatory. There being no further need to carry lots of loose stuff out to the telescope in the open. Then protect it all from frost and dew usually in the pitch dark. Followed, of course, by packing everything up again even later than I started. When literally everything is covered in dew or ice.

I've tried various storage tubs, including clear plastic, but these are rather vulnerable to knocks. They also offer no mechanical protection to the items they hold during transport. My cheapo, plastic, partitioned, eyepiece storage box is now overflowing with two extra low powers for the binoviewer.

Perhaps I should consider built-in, secure and protective plywood shelves doubling as storage boxes? Nothing wants to be permanently out in the open in case of unexpected rain though the open slit. I have already discovered that any paper left lying on the shelf soon gets damp.

On the southern side the telescopes are usually well above head height and never need to dip downwards. So the southern half of the floor becomes useful as a free area for moving around. It is a safe place to stand to look around the sky through the observation slit for new objects rising in the east. Or sinking below the trees to the west. Though neither view is very accessible due to the height of the bottom sill of the observation slit.

The western side of the observatory is dominated by the stepladder. With its projecting handrails and the large and heavy trapdoor. Or the large and dangerous hole in the floor when open! Now safely lit by a red LED bulb placed inside the hollow pier, 'dog kennel.'

The double door out to the veranda is proving awkward enough in practice not to get much use in the dark. It ideally requires the trapdoor to be down and closed for easy access. Squeezing past the handrails, while ducking down is possible with the hatch open, but difficult in bulky winter clothing.

The doors cannot be opened fully back because of the geometry of the octagon and the width of the veranda. This means they must be closed behind me to use the rest of the veranda freely. Just the price of having no plans and relying on intuition. Once on the veranda the 2' width is fine for one person to move quickly and effortlessly around the outside of the dome.

For the moment I have settled on a computer shelf hanging on the eastern side of the massive wood and plywood pier just above lap height when seated. The AWR electronics are mounted on the southern side of the pier. Well out of the way of moving telescopes and my often clumsy movements in the dark. Though I have added a second red, LED bulb overhead.

The slope of the pier sides would provide ample room for shelves placed near the top. Providing they did not risk collisions with telescopes pointing up high. Since my feet set the limitation on how close I can stand to the pier I would not be likely bump into these shelves or tiered storage areas. While shelves jutting from the octagon walls would be highly vulnerable to my colliding with them in the dark. The pier is easily massive enough not to worry about vibration while selecting eyepieces or accessories stored there.

The overhead red bulb does not spoil my dark adaptation [so far.] It provides a soft flood of deep red light to allow me to safely monitor telescope movement during slews. It also allows me to reach the eyepiece, or change to another, in relative safety. A white light provides a working light after dark if needed to make repairs of adjustments. The cable to the white light must be unplugged to avoid tangles with the dome rollers and steering wheels. 

A chain of dim, red LEDs mark the perimeter inside the dome to help me avoid collisions. I still haven't become accustomed to dome rotation. I always feels as if the octagon and floor are rotating! While the dome is staying perfectly still. Normally I stand still and pull the ribs around one at a time. This is much safer than walking backwards along with the dome until I fall over something.

The red, LED clock is flat on the wall, to my left, when seated at the computer shelf. It is just bright enough to provide some working light when it is dark enough. I wish I could turn off the double flashing colons! Perhaps some black tape would mask them if I applied it neatly.

If I was to offer advice to any would-be dome builders/owners, I would suggest the following: Make, or buy one, at least two feet larger in radius than the horizontal length of their longest telescope. That is at least four feet greater in diameter than the telescope's maximum length including a decent length of dewshield on a refractor. The diameter of the dome is critically dependent on telescope choice. So choose wisely!

I keep finding myself trapped against the dome when I want to look "straight through" the 7" without a diagonal. A diagonal is not always possible when using a binoviewer. It eats up 4" of your focal length in the much the same way as does a diagonal. Using both together would mean chopping large chunks off your telescope tube. Not many people would want to do that.

My 3m [10'] dome is proving much too cramped [at times] when I'm using the long tube on the 7" f/12 refractor. This is largely due to the low altitude of the sun at 55N. I could go back to the folded form but just prefer the conventional tube for aesthetic and practical reasons. Adding four feet or 120cm would mean a dome 4.2m or 14' in diameter. This means a very costly increase in size if you buy a commercial dome!

Unless, of course, you are willing to consider modifying one of the hemispherical, calf rearing shelters. These are of the correct size but heavy and would need a base ring, supporting walls with rotation rollers and an observation slit.

You can't just hack a huge slit out of the GRP dome without serious reinforcement at the zenith and edges of the slit. This reinforcement really ought to be bonded into the rest of the structure for adequate strength. Preferably while the complete dome is erected on a flat surface to avoid distortion when assembled. A curved steel, tubular frame, following the edges of the slit would probably be best. Had I known, what I do now, I would have overcome the weight problem in getting such a dome onto a tall but larger building, using a hired, telescopic loader.  

These domes come in three large pieces. Which helps when lifting them onto the observatory walls.  They are remarkably competitively priced compared with anything on the astronomical observatory market. Though care in modification is essential to avoid disappointment, weakness or even danger of collapse. Still a far cheaper and simpler project than starting to build such a large dome from scratch!

*