The Ash Dome

Having decided on the manufacturer I now had to settle the specification. The minimum dimension across the base was 10 feet 6 inches. I would have liked a larger dome, but there was not room. From my tour at Bayfordbury I knew that this would accommodate a 16" Meade because this was the setup there.

The dome could have a standard shutter or an extra wide one: I opted for the latter. This I found to be a good move, since it gave a slot of about 2 hours. When imaging piggybacked the decision was especially useful. At some points in the sky the telescopes are parallel with the horizon, and this effectively halves the width of the opening. At other points when running more vertically the slot can last for hours. Now the bad decision: Ash offers an option of a clear lanphier shutter that can be attached to a draw box, giving a totally enclosed window on the sky at any position.

I thought this would be a good idea for displaying the glories of the sky to visitors, but I never had in mind to image through glass. Visitors come and go, but I have to live with the shutter full time. As a target rises or falls, this can entail moving the shutter by either parking it or raising it; you will only be doing this at a time of good imaging sky! The basic dome comes with a bottom section, which hinges outwards so that, once opened, the whole slot is yours for the night.

Having made my selections the order was placed, and it would take about 3 months to deliver. This fitted in very well with the building schedule, and, on time, I received the message that the dome was about to be dispatched. Not only this, but I was e-mailed a photograph of the assembled dome at the works outside Chicago, with my name on it. This was a clever ruse by Ash. The message was, "If it does not fit together, the fault lies with you, the buyer."

Delivery was to be to at the Southampton docks, and the shipping cost was a separate item in my Ash bill. It was for me to get the container from Southampton to Long Crendon, a distance of around 80 miles. Needless to say this cost more than the Chicago to Southampton stint.

The big day dawned, and since the truck cannot get anywhere near my house I arranged a rendezvous in a nearby lane (Fig. 5.15).

You will see from the white painted stones that the adjoining owner was prissy about his grass: the result was a tirade of abuse, which was enjoined by another resident. We proceeded to open the container.

Figure 5.15. The container lorry arrives.
Figure 5.16. Terry is somewhat daunted by the contents of the container!

What a sight greeted us! Terry was Chris's right-hand man; he could turn his hand to most things, but was this a step too far? (Fig. 5.16). The first surprise was that, apart from the shutter, all the components were small. There was a melee of bits and pieces, steelwork in all shapes and sizes, and unintelligible timber parts. There were boxes of nuts, washers, shims, and various other things. This all came with a 76-page book of assembly instruction, an extract from which appears as Figs. 5.17 and 5.18.

My first thought was, "What have I done?"

The first step was to try and identify the various parts; we made some progress but some bits baffled us. (At the end of the job a couple of small parts were left over. Was this someone at Ash having a joke?) The instructions proved to be splendid. Each step was clearly identified with copious drawings that clearly demonstrated what had to be done. As the building was of timber, I had arranged for a local steel fabricator to make a steel ring beam for the dome walls to sit upon (Fig. 5.19).

We fully understood why the instructions emphasized the need for everything to be totally level. The base timbers of the dome walls married up to the ring beam, so we had got that right. Next we assembled the plywood walls to the dome (Fig. 5.20).

Now, the fundamental move of installing the dome runners: the more accurate the leveling, the better the dome would operate. Chris is very good at attention to detail, and he got this spot-on (nowhere in its trundle does the dome labor) (Figs. 5.21 and 5.22).

During the construction there were a couple of occasions when we needed some clarification. An e-mail query to Ash always resulted in a rapid reply with a solution.

Ash Dome Observatory
Figure 5.17. An extract from Ash's instruction manual.

There is a footpath crossing the field adjoining my house, and, as the observatory started sprouting in the air this caused us to get some funny looks (the path is now known in the village as "Observatory Walk"). This circular plywood upstand looked very "raw," but as the metal cladding was installed it adopted a more businesslike

Figure 5.18. The shutter "on the road".
Roller Ring Beam Observatory
Figure 5.19. Positioning the steel ring beam for the observatory.
Figure 5.20. Assembly of the dome wall.
Figure 5.21. Positioning the dome runners.

appearance (Fig. 5.23). I liked the fact that Ash supplied an extra piece of cladding in case you spoiled one. We were now at the stage of completing the waterproofing arrangements. The tiled roof had to be fabricated and tiles and leadwork individually cut to suit the circular dome walls. I considered it essential to have access to a balcony at dome level (Figs. 5.24 and 5.25). Not only would it give a good means to check incoming weather, but being high and dark, it would offer a splendid vantage point for viewing the heavens with the naked eye and with binoculars. The roofline was carried up to safeguard the balcony on two sides, and the third side had to be co-joined to an existing tiled roof in a most complex fashion.

The only mistake made was the way in which rainwater was to be discharged out through the roof. This was simply by means of a lead-lined unenclosed opening in the studwork, and it did not occur to us to think about animals. Some months later, I heard noises in the roof and yes, we had rats! We straightaway closed all possible access points and put down poison. The rats eventually succumbed, and I was fortunate that the remains were all within reach of the trap I had made for the purpose of planting poison.

Now the exciting bit: dome assembly, and Terry missed it. He reported in sick, but we thought his illness might be related to an extended visit to the pub on pay night. The dome panels were made of aluminized steel, and the idea was that you slid them together with the aid of some dishwashing fluid (Figs. 5.26, 5.27 and 5.28).

Figure 5.24. The high level observation deck.
Figure 5.25. Tiled roofing.
Figure 5.26. One of the dome sections.
Figure 5.27. Starting assembly of the dome.
Figure 5.28. The dome panels slide together with surprising ease.

It all sounded a bit hit and miss, but, with firm pressure, they knitted together surprisingly easily. In only a couple of hours or so the dome was completed on a gorgeous autumn day, and we stood back to admire the scene (Margaret was not so enamored).

Arriving the following day Terry had missed all the glory and swallowed hook, line, and sinker the story that two gorgeous young Russian ladies had popped in to see us, sent by Oxford University. (They actually do this to me sometimes!)

Now came the most difficult operation of the whole exercise: installation of the shutter. Since I had ordered the oversize opening it followed that I had an oversize shutter. There is actually a crane depot at the other end of the village. Somehow the driver managed to squeeze into the garden and the process commenced. It was a squally day, and the lads were reaching out for the shutter as the crane driver offered it. A gust of wind sent it spinning like a top, and I feared for the boys' hands (Fig. 5.29).

All praise to the crane driver, who in no time took it out of range. It was sometime later before things had calmed down sufficiently to have another try. Slotting the shutter into position and securing it had to be the most difficult part of the whole operation. Of course, at ground level it would have been so much simpler. After that was done the crane driver maneuvered the box containing the roller shutter, which sits at the foot of the shutter opening. Next followed the installation of the motors driving the rotation of the dome and the lifting of the shutter (Figs. 5.30, 5.31, 5.32, 5.33).

Figure 5.29. Installing the shutter.
Figure 5.32. The curtain box attaching to the lanphier window.

With these in place the dome was completely fabricated. Another black mark for the lanphier is that the box for the blind has a nice right angle corner, which is exactly what you bang your head on in the middle of the night when exiting to the balcony to check the sky.

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  • Wayne Watson
    Have you imaged through the window of the shutter? If so, did you get favorable images?<br /><br />N. California
    8 years ago

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