MONET Factory Tests Sep 2004
MONET telescope in assembly hall with other telescopes nearby
Vertical fork with covers installed. Altitude drive and encoder is on left (black). M1 and supports are in the lower section just below the axis.
Herr Halfmann added for scale. Other telescopes in background.
Image derotator on opposite side of Fork from Alt drive. Drive is on top and outer section (to right) rotates to compensate for field rotation as the telescope tracks. CCD mounts to the off-center section that contains the filterwheel. The guider/autoguider mounts to the smaller tube at the bottom. Note that hanging cable is for the filterwheel and must wrap around the black cylinder. A cable support is being discussed to support CCD and autoguider cables out from the side of the fork. These cables will either twist or also have to wrap around as the telescope moves.
Slightly off-axis view of the derotator and filter wheel assembly. Note that both the CCD camera and guider/autoguider must rotate and risk their cables being twisted.
Derotator shown from below. Filterwheel assembly and cover is to upper left, guider attachment is down and derotator motor/drive is top and to right. Cable hanging down from the filterwheel must wrap around the black cylinder just to the right of the guider attachment point. Cable from the derotator motor, enters the fork. Asked about a separate access port for the filters so that the CCD does not have to be removed to change or clean the filters.
Side view of derotator showing cable that is likely to snag on the bolts…
Our telescope was not disassembled for the tests but an almost identical telescope had covers removed so we looked at it. The area shown is looking down into the oil sump and with the fresh oil one can even see the bottom of the pan. Since the Az axis of the telescope is above this point, the oil bearings and drive are located toward the top of the image.
This was near the oil sump and was described as the float valves for the oil level. I am not sure how one gets to these for service?
Blue structure is the base for MONET-S so is identical to our base. The outer trough is the oil sump and the AZ pintle bearing and drive mount in the center.
The oil pump which is roughly 90 cm x 90 cm x 130 cm high. There are two pumps one to pressurize the oil for floating the AZ axis and the other to return the oil back to the pump. Our pump was located behind some stored material but only differs in color.
Name plate on one of the pump motors. Ratings look to be suitable for our power source. I did not get the other motor nameplate but it looks similar though it has slightly different rating.
Electrical control cabinet which is pretty much full so will be supplemented with a half rack to house additional computers for controlling the telescope and autoguiding. Docs provided seem to indicate the cabinet has some type of cooling system built into the right side wall.
Interior view of the cabinet. Upper portion is circuit breakers, then relays all connected by mostly blue wire. Not very many labels which we complained about. The cooling unit again shows up on the right interior wall while the front door is in the right foreground. A lot of stuff is crammed into the middle section and it is located two levels deep. The front equipment is the ETEL AZ/ALT and derotator step drivers. Behind them are a PC-104 computer for managing the various controllers and subsystems along with several other computer boards and a small UPS. Just below them are the focus and M3 (not used) rotator. Next to them is a small GPS unit for timing. Low on the right side wall is the battery for the UPS. In the bottom of the cabinet is a 3-phase transformer which is rated at 5kVA so a max of 12 A. The transformer is supposed to be only for the ETEL motor controllers but it does seem rather hot (50C) while providing ~200W according to info received. Rick will have Halfmann verify the actual current required to operate the telescope so we have confidence it will fit within our local power budget.
Better view of the lower part of the electrical cabinet. The encoder box on the right is for focus.
One of several electrical boxes on the AZ axis. The cable to the right passes through the center of the AZ axis back to the electrical cabinet.
This is a multifunction handpaddle but not a traditional unit as it is mainly used for set up and maintenance rather than routine operation. Documents refer to it as a bottle which appears to be the nearest available translation.
Thies weather station still in the box. There is also a central control box which will be outfitted with a BECK Microcontroller which will then send data via Ethernet. There are other components such as humidity, rain, etc sensors.
The secondary is visible with the cover removed. Vents will be cut in the protective shroud to permit better air flow over the mirror. Also one of the mirror cover plates with its linear actuator are to right.
Secondary support and drive screw. Spider support is to left.
Looking toward M1 which was covered at this point. The baffle tube is in the center and contains the #3 mirror for bending the light path to the side port. Both M1 covers are shown but the left one is a bit more complicated since it also has a cover for the baffle tube.
The black block and bearing assembly are one of the axial supports. The bearings appear to be friction type rather than flexures. I asked but never did get clarification. After returning, forwarded a link to a company that makes flexures similar to what we use. In order to access these and the radial supports, it seems several plates would need to be removed. The hole (one of 3) allows access to the back of M1 for removal/installation once the mirror cell has been removed from the telescope. Removal from the cell is with a 3-post fixture similar to what is used with the 107 #2 mirrors. We will have to fabricate before the first removal for recoating. Halfmann will bring the fixture over for installation so we can get measurements at that time.
Mirror cell removal fixture side view. See next picture.
End view of removal fixture. This unit is also not delivered with the telescope as the cost was considered too high. We would need to build this fixture or something similar prior to first recoating of M1. The basic idea is that this fixture would be assembled under the M1 cell after covers are removed. Then the cell is lowered until it rides on the upper roller assembly. From there it can be rolled to the side until the dome crane can lift the cell off. From there the cell can be lowered for removal from the dome. There are numerous details to be worked out about the whole process, but similar activity will be required to install the cell when it arrives.
So that is pretty much a summary of the photos though additional images are available at http://nexus.as.utexas.edu/~green/monet_pix.html if you are interested.
Still to be done are some minor mods/changes/fixes
based on the review, move the telescope outside to their roll-off dome/shed for
on-sky tests, then pack and ship possibly in Dec. Likely assembly will begin
Feb 2005 after the cargo container(s) arrive though no official dates have been
identified. Expectation is that they will be uncrated on the back parking lot
of the VC by Halfmann personnel perhaps with our support. The two main
telescope components will probably require a crane to offload, then a flatbed
truck to haul to the site and the crane again to set in place. At least part of
the time Halfmann requested an inside work area with hoist capable of handling
~1000 kilos for assembly of the mirror cell and primary. Candidate locations
are 107 bay (possible hoist problem and slowdown of HET aluminizing), HET bay
(same effect on HET aluminizing) and PP shops (possible hoist problem.)
Halfmann requested we have on hand sufficient tarps to cover the exposed
equipment at the parking lot as well as staging around the site in case of bad
weather. The largest item to be handled by the rented crane will be ~9000 kilos
with the crane needed for about 3 days. We stressed to Halfmann that we do not
have a way to remove the cargo containers from the delivery trucks so they will
have to provide for that through their shipper. It was agreed that once the
delivering agent in the
Shortly Halfmann will supply a parts list for our review and recommendation of components to spare. There will be a limit based on a percentage of the contract value. Other documentation will also be released at about the same time due to meeting of a project milestone with completion of factory tests.
Halfmann through their contractor 4PI will provide a Java based program called PILLAR which provides for basic manual operation of the telescope. Since the telescope is an Alt/Az mount, tracks must be generated in advance or real time in order to follow a target. The existing software appears to operate by moving to and then following the entered RA and DEC values for an object. But the autoguider software, main (local) control software and robotic management software are in early stages of development. From our examination of the PILLAR software it appears that only sidereal tracking is available but there may be something we have not discovered.
Overall MONET appears to function very well and is certainly rugged enough that it should be very rigid and stable in operation.
Comments, suggestions, etc. are welcome.
Earl
green@nexus.as.utexas.edu