Telescope Reviews: Post a picture of your refractors (PART 5)

Hi folks,

I thought I'd share the new imaging setup. I don't have the luxury of a garden large enough to host a dedicated observatory so the solution I started planning a year ago had to at least look presentable during daylight.

The pier was made in two stages with a deep foundation poured using regular cement plus a plasticiser with 2 metre stainless steel rebar protruding about a metre above ground level. Once that had cured I then poured the top half into a mold and also poured the detachable top upon which rests the armillary. I used the same recipe for the cement with the addition of a dye to give a stone effect. To give an idea of scale the pier without the top stands just under 1.3 metres (50 inches) tall. When I poured the pier I embedded four stainless steel eye-bolts. This was done using the same stainless steel circular plate you can see in the top right image to get the positioning absolutely precise. The two circular plates were made for me to my design by a laser cutting company so I was able to specify a tight tolerance between the width of the various bolts and the holes they fit through.

Assembly is pretty straightforward. There is still a very slight (small fraction of a millimetre) play when the two plates are attached but I always make sure I rotate each one fully clockwise before tightening up the nuts. The aim was to get a totally repeatable set-up each time and indications are that I actually see an accuracy of about 1 minute of arc. The heaviest detachable item by far is the mounting itself but I've avoided any hernias so far!

Here's a closer view of the telescope where you can just about see the four bolts holding down the bottom plate and the bolts fastening the top plate to the bottom one. The mounting is bolted to the top plate but you can't see that in the image.

The equipment list is:

TEC 140 telescope: 140mm objective and a field flattener at the other end giving f/7
Kendrick Dew Heater: Essential in the UK
ASA DDM60 Pro: The Pro version includes a USB hub
Starlight Instruments motorised focuser
A power distribution/switch box
An FLI CenterLine filter wheel
An FLI ML16803 astronomical CCD

The USB hub in the DDM60 Pro mount means that all I need is a single 12V power line and a USB connection running to the mounting. Both power and USB are routed internally and are available by the telescope which means no tangled cables. The focuser, filter wheel and camera are all controlled via USB as, indeed, is the mounting itself. As a result, although I need a micro-ATX sized computer relatively close to the telescope together with a 12V power supply, I can take advantage of a long HDMI cable and a wireless mouse and keyboard to control the whole shebang from inside my conservatory which is just out of shot on the left. Luxury!

Testing has gone really well and I've already demonstrated an ability to take 1,000 second exposures unguided. That's down to some remarkable technology in the ASA mounting, although I'll take credit for doing the calibration work.

Bob.