Ribbon Cutting on the Orion ODK12, 17.10.14

The New Dome, erected during the summer of 2008, starting in April, by members of the Society, at the end of Austerfield's field, adjacent to the Old Dome.

The Observatory Log reports details of the work as it was done.

It's a 3.5 Metre GRP dome by Sirius of Australia, on a 4.5 Metre square base of 8" thick concrete. It's mains powered from the old dome which is powered from the main building by an underground cable.

There is also a data line connection from the new to the main building via the old dome, enabling it to send data, or be controlled from the main building or from the internet. This includes the telescopes and cameras in it too, of course.

The new dome's work will be primarily, though not exclusively, astrophotography, leaving the old to handle visual work.

There is an insulated and carpeted floor inside taking the feet of the photographers 7" above the concrete, and in the centre is a 10" dia. steel pier, with a 600mm square base, bolted to the concrete. A 900GTO Astro Physics mount sits on top of the pier, and carries an Orion Optics ODK12 telescope. Its 12" aperture has a focal length of 2040mm (f/6.8) for medium to long focal length work on planetary nebulae, asteroids, planets, doubles etc., and a Takahashi FSQ106ED refractor for wide field work, nebulae, star fields etc.

This drawing shows the storage space built into the dome walls during the Autumn of 2015. The cupboards form a full circle of storage space 4' high and 15" deep, and is for storage of spare telescopes, loan-out telescopes, show equipment like the gazebo, and all the society's equipment currently being held in members' homes, and the society's Library too. There is also storage in the cupboard under the telescopes. This houses mostly eyepieces, extension tubes, the PC, batteries etc., items directly related to the telescopes above.

Aims for the future
Solar work will be done with the Solar Spectrum system on the Sky-Watcher 80ED in the old dome, and will have adapters to fit to the ODK12 in the new dome. Fitted to the Skywatcher 80ED it will be available for field work, schools, shows etc.

Though the society will continue to use the telescopes from within the dome, we are preparing the system for remote use, to which end we have a PC and all relevant equipment located under the mount.

We also plan to use the equipment to make webcasts of solar activity, to be available for local schools, and Lunar and planetary activity during early evenings, for members and the general public.


Instructions on Setting Up and Running the Photographic Dome.

A. After opening the door, reach to the bottom left for the light switches, the white one for white light, the red one for the red lights.

DO NOT TOUCH the covered switches below them, these are likely to turn all power off to both domes, and will require reconnection in the nearby classroom.

B. Remove the dust cover and store it in the western alcove.

C. There are 8 switches to operate to start the system.
                1. the Dome Rotation. On the box on the SW wall of the dome
                2. the Dome Shutter. On the rotating part of the dome at the bottom left of the shutter
                3. the Computer, the switch is on the front of the PC, under the folding table on the west    of  the central cupboard.
                4. the Computer Screen, on the front of the screen

               5. the Power to the mount. On the south face of the mount. There is no actual switch, but a round plug to be pushed into a round socket. There is a telltale light that must light up RED to indicate it is connected, if this is yellow, it means NOT connected. Pull out and try again. If it persists in showing a yellow light, you must use a penknife to very slightly open the central pin connection in the plug, re-insert the plug. That means VERY SLIGHTLY. VERY SLIGHTLY means VERY SLIGHTLY!
6. the Serial plug to the left of the Power switch, on the south face of the mount. Push it into the upper of the two sockets.

7. The power plug for the cooling fans should be plugged into the socket in the rear face of the ODK, below the focuser.

The cable should be found hanging from the same loop as the serial plug is, as shown by the yellow arrow, then plugged into the socket under the focuser on the base plate of the ODK. You should hear the quiet hum of the 3 fans. These will help cool the primary and keep moisture off the primary.

8. As a means of keeping moisture off the optics we use a heater in the form of a 1.5w/12vdc bulb lowered into the tube on the end of a length of cable. This must be withdrawn, the bulb removed (this acts as a switch) and set aside under the mount. The cable has a prominent knot in it's length at 22" from the bulb to ensure you don't lower it too deeply into the tube and touch the primary.

D. Wait for the PC to start up and display the Ascom Dome Control panel. This will take a few minutes. Then click the "Connect" button on the panel.  Then wait for the PC to process these commands, which will end when TheSky software screens a part of the sky that the telescope is pointing at, and the dome has rotated to its Home position, the north. You will now have to highlight the Ascom Dome Control panel to bring it to the front.

E.  Click the small square labelled "Slave", and the dome should rotate to where the telescope is pointing. In most cases it will therefore not move much as the normal home position for the telescope is pointing to the north too.

F. She is now ready for action.

This instrument is not as simple as the Meade in the smaller dome. That telescope sits on top of a fork mount and cannot run into the pier, or do itself damage, though it can get "lost".

This is a German Equatorial Mount and consists of the telescope on one side of the mount, counterbalanced by the counterweights on the other, and either can run into the support system. So it is good common sense, when sending her to a target, that you watch carefully, with a finger covering the STOP button. This is on the handset in the middle of the Direction buttons.
A requirement of GE mounts is that the telescope must be square to the mount on both sides, but I haven't completed that yet, so she is slightly different when on one side of the mount to when she's on the other. This means for instance, that when moving from target to target with the telescope on the east of the mount, she points very well, but will be slightly out when asked to point to a target that requires her to move to the west of the mount. It may then be necessary to re-calibrate her to a nearby star that you know, on the new side of the mount, before returning to the originally aimed at target. From then she will perform well till asked to move to the other side of the mount when she'll need "re-calibration". This is equivalent to "Sync" on the Meade in the other dome. All this will end when I get round to matching both sides up to each other. But it involves testing and shimming the telescope tube and is a long job.

A feature of GE mounts, that affects astrophotographers only, is that the camera will be turned upside-down when the telescope is moved to the other side of the mount.  But this mount has the ability to track past the meridian for up to 6 hours, and it will allow you to take it well past the meridian if you do it with the handset, but will not if you "send" it there with TheSky software.

To Re-Calibrate, centralise a KNOWN and RECOGNISED (make sure you do recognise it) star in the eyepiece, using the handset. You may have to change the drive speed to be able to do this accurately. Ensure the chosen star is actually the one in the dialogue box, then click the "Telescope" button on the top row of the dialogue box. This will give you access to the "Re-Cal" button and the "Sync" button. Click on the "Re-Cal" button, and NOT on the "SYNC" button. Take great care on this point, DO NOT USE THE SYNC. BUTTON. 
If you press the SYNC button, the mount will be expecting to be sent to a star on the mount's own internal list of stars, but if it is sent to a location not on this internal list, it will be thrown into disarray, and will have to be turned off and re-started.

Speed changing is done on the handset, by repeatedly pressing the "6" key, after pressing the Menu key, till a suitable speed is seen on the handset screen. Similarly the "8" key controls the tracking speed.)

 She is now ready to work on this side of the mount.

The controlling of the telescope is done through TheSky software, on the PC. By clicking on a chosen target on the screen, a dialogue box is screened. Check that the dialogue box refers to the chosen target, click on the SMALL GREEN TELESCOPE ICON at the bottom of the box. Have your finger ready near the handset's STOP button, in case the telescopes or weights get too close to the mount.

Provided the main screen is high-lighted blue as being in operation and the dialogue box isn't high-lighted blue, the scale of the star chart on the screen is controlled by the PgUp and PgDn keys on the keyboard, or the small "+" and "-" on the edge of the software screen, or by the roller on the mouse.

You can control the system by either the PC or the handset, but it is sensible to use one or the other but not both when sending her to targets. Better in all respects to use the PC, with the occasional Re-Calibrate with the handset.

This is a very costly piece of precision engineering and must be treated carefully.

The focusers. The primary purpose of the equipment in this dome favours astrophotography and an important part of that is focusing the cameras. The weight of the camera can be quite large so control of the focuser's resistance to slipage is important.  

Underside view of the ODK focuser

The ODK focuser's resistance to slipage is controlled by the 3 Allen screws on the underside, 2 smaller ones and a large central one. Don't make these too tight or you'll lose all feel of the focusing. The larger thumb screw is a lock, there is another on the top face of the focuser.
 For the Tak, the control of the focuser is vested in the small lever near the middle of the focuser.  Again don't tighten this too much or all feel is lost.

Closing down.

Click the "X" at the top right of TheSky software screen. This will throw up a dialogue box reminding you that the telescope isn't parked, and do you want to Park it. Click Yes and it will be done. A second box will screen asking if you want to save things. No you don't want to save. The planetarium software will close down, leaving the Ascom Dome Control panel on screen. Click on the "Close Shutter" button and the "Park" button. When they've done, click on the "Exit" button. It will ask if you realise that the telescope will be disconnected. To which you respond, "Yes, I know, do as you're told", or words to that effect.

Then Turn off the 8 switches you switched on at the start, ie. 

Dome Shutter, 
Dome Rotation,  
Computer, using the Start button on the screen,
Screen, the telescope's 
Fans and the mount's
Power and
Serial connector
Lower the 'tube heater' into the tube, up to the knot in the cable, having replace the bulb in its holder.

Ensure all the eyepieces and other items have been returned to their correct storage places. Fit the covers on both telescopes and the finder, at both ends.

Cover the telescopes with the dust cover, recheck that all 8 switches are off, turn out the lights and lock up.
All the above is basic and will work well, but, and there's always a "but", if you make a mistake in anything, it will be thrown off course and may not do what you want from then onwards. The correction is usually easy enough, but requires more knowledge, and this is obtainable through practice. So come down and practice.
This situation applies equally to the Meade, though the chance of damage is much less likely there.

BJ 1.1.13/BJ 8.2.15/BJ-25.1.16/BJ-17.4.16/BJ-17.9.16