Hey guys,
I've uploaded a video of Polarbear in action:
http://www.youtube.com/watch?v=WY4SNlla3zk
Still pretty fast, despite the imbalance!
Saturday, July 25, 2009
Telescope moves!
Richardson sent out a person yesterday to start on the servo, and I am happy to report that the telescope is now moving under it's own power. As you can guess, there are some issues. The biggest one is that we can only hit 80% of the spec velocity in elevation. This could be due to a number of things, like imbalance or excess force on the friction drive, but more on that later. I want to get Dave to make a movie with his new camera.
On another note, Nathan showed up also, and Dave is hoping that I will focus on him for comic relief.
On another note, Nathan showed up also, and Dave is hoping that I will focus on him for comic relief.
Friday, July 24, 2009
Photogrammetry
I have not posted in a long time because the last week had been grueling. I have been up all night in the dark for about five days, and I think I have finally recovered.
We did photogrammetry, and have had mixed results. The primary still appears okay, although I do not think that our setup is precise enough to see something subtle. The panels have also been aligned, except for one. The measurements were showing that one of the panels was off by 0.08 inches, while the rest were about 10X closer. Al came up with a way to suck down the bad panel, but in the process, he and Brian found that the panel was actually resting on the Primary.
After yanking the panel off, however, it sill looks like Al's contraption will have to be installed after all, a job for tomorrow.
But I am getting ahead of myself, we were hit by a couple of problems, the first was that it rained on almost every night, and we not only lost the time that it was raining, but I am also afraid that the mirror would do weird thermal drifting while drying.
In the end, we were not able to align the secondary. I think the problems were in both the software, and the adjustment mechanism. I think I will work on both, an then we will try again. They cryostat mount is still not here, so it is likely that Jay, the photogrammetry person, will have to come back in a few months to try again.
Pictures will be coming later
We did photogrammetry, and have had mixed results. The primary still appears okay, although I do not think that our setup is precise enough to see something subtle. The panels have also been aligned, except for one. The measurements were showing that one of the panels was off by 0.08 inches, while the rest were about 10X closer. Al came up with a way to suck down the bad panel, but in the process, he and Brian found that the panel was actually resting on the Primary.
After yanking the panel off, however, it sill looks like Al's contraption will have to be installed after all, a job for tomorrow.
But I am getting ahead of myself, we were hit by a couple of problems, the first was that it rained on almost every night, and we not only lost the time that it was raining, but I am also afraid that the mirror would do weird thermal drifting while drying.
In the end, we were not able to align the secondary. I think the problems were in both the software, and the adjustment mechanism. I think I will work on both, an then we will try again. They cryostat mount is still not here, so it is likely that Jay, the photogrammetry person, will have to come back in a few months to try again.
Pictures will be coming later
Thursday, July 16, 2009
Panels and countrerweight
The old counterweights were lifted into place this morning, and now the telescope is almost balanced. We will not know for sure until the torque is measured again. We are currently waiting on a connector before we can turn on the motors.
We have a resident underneath the telescope. We call him stumpy, for obvious reasons. He comes out and pecks at pebbles, but someday he will get a real bug. There are tons of these little lizards everywhere, and sometimes they will freak you out if you are not expecting it.
Brian worked on the panels for most of the day, and they are basically in the right spot. There is a fifth tab though, and some of these might need to be modified. We wont know if the panels are in the exact right spot until the photogrammetry is done, which should start this weekend.
This is how the telescope was left today, you can see the counterweights in the new location.
We have a resident underneath the telescope. We call him stumpy, for obvious reasons. He comes out and pecks at pebbles, but someday he will get a real bug. There are tons of these little lizards everywhere, and sometimes they will freak you out if you are not expecting it.
Brian worked on the panels for most of the day, and they are basically in the right spot. There is a fifth tab though, and some of these might need to be modified. We wont know if the panels are in the exact right spot until the photogrammetry is done, which should start this weekend.
This is how the telescope was left today, you can see the counterweights in the new location.
Wednesday, July 15, 2009
Old Photos
Wow, David gave me some old photos of Pauls lab from back in the day. I wonder who these people are?
New tabs and counterweight
The internet in the super 8 has been out for the last two days, so I have not updated in quite a while. A lot has happened in the last couple of days.
Here is a photo of the shadow of the panels, right before they were removed. You can see tha the gap is a little bigger on one side. The panels just could n0t be mounted in the correct position, so it meant that the panel tabs on the support needed to be reworked.
It also turns out that Caltrans is doing major road work on 168. Every time we go up and down, we have to wait about 20min for a "pilot" car to lead us around the crew.
Al is also relocating some of the counterweights to balance out the primary. It tuns out that the CG is only 3inches off, but at 30,000lbs, 3 inches means a lot of torque. Here is a monster tap that Al is using to mount the threaded rod into some 3" thick plate .
The panels have all been sadly removed, and they are all sitting in this box.
On Tuesday, the hard work began of drilling and tapping for the counterweights, and welding the new tabs. I had to get a burn permit from the Bureau of Land Management, and we have to keep this awesome backpack super-soaker around to fight fires. Al and Brian are working both ends of the telescope.
Here are the new tabs that have been fabricated.
Drilling through 3" of steel plate leaves a lot of shavings.
All the drilling and tapping is mostly done now, the tabs are all welded on, and Marius is now painting the saddlebags. The Photogrammetry needs to start next week, so we are scrambling to be ready.
Here is a photo of the shadow of the panels, right before they were removed. You can see tha the gap is a little bigger on one side. The panels just could n0t be mounted in the correct position, so it meant that the panel tabs on the support needed to be reworked.
It also turns out that Caltrans is doing major road work on 168. Every time we go up and down, we have to wait about 20min for a "pilot" car to lead us around the crew.
Al is also relocating some of the counterweights to balance out the primary. It tuns out that the CG is only 3inches off, but at 30,000lbs, 3 inches means a lot of torque. Here is a monster tap that Al is using to mount the threaded rod into some 3" thick plate .
The panels have all been sadly removed, and they are all sitting in this box.
On Tuesday, the hard work began of drilling and tapping for the counterweights, and welding the new tabs. I had to get a burn permit from the Bureau of Land Management, and we have to keep this awesome backpack super-soaker around to fight fires. Al and Brian are working both ends of the telescope.
Here are the new tabs that have been fabricated.
Drilling through 3" of steel plate leaves a lot of shavings.
All the drilling and tapping is mostly done now, the tabs are all welded on, and Marius is now painting the saddlebags. The Photogrammetry needs to start next week, so we are scrambling to be ready.
Friday, July 10, 2009
Dave's Turn
Albert and Brian are arriving super early these days, and they were able to check the balance of the telescope before we arrived. San Jose had requested that they do the standard balance test, by measuring the torque required to move the telescope at many different elevations. It turns out that the orientation seen below is the min torque, meaning that the center of mass is right above the elevation axis. The plan is to now add counterweights below the axis, and we are waiting for San Jose to make a recommendation.
There is a minor problem with the elevation cable wrap, it hangs on one of the counterwieght bolts.
Brian was able to rinse away all most of the residue from the recent rain. This photo also shows the current gaps in the panels. We are still waiting for a recommendation on how to deal with the panel hardware interference.
It was Dave's turn to crawl into the hole today to redo the shims. He spent half the time with his legs hanging out of hole, and just like in the cartoons, he kept kicking them around as he was squirming around in the the yoke.
He had to poke his head out once in awhile to let the blood drain.
We re-created the scene in the box for the blog.
Here's how we left the telescope today. It is in sad polarbear orientation, but I am actually happy that our problems are slowly getting resolved.
There is a minor problem with the elevation cable wrap, it hangs on one of the counterwieght bolts.
Brian was able to rinse away all most of the residue from the recent rain. This photo also shows the current gaps in the panels. We are still waiting for a recommendation on how to deal with the panel hardware interference.
It was Dave's turn to crawl into the hole today to redo the shims. He spent half the time with his legs hanging out of hole, and just like in the cartoons, he kept kicking them around as he was squirming around in the the yoke.
He had to poke his head out once in awhile to let the blood drain.
We re-created the scene in the box for the blog.
Here's how we left the telescope today. It is in sad polarbear orientation, but I am actually happy that our problems are slowly getting resolved.
Star Destroyer
Marius has finished his magnum opus in 80/20. It is as dangerous as it looks.
The air conditioner just barely works. It was a cool 78 degrees, although I could swear it was 76. The key was to keep two of windows closed, and to turn on the system at noon.
The PDU is basically ready to go, but there are some lingering issues with the telescope. There are three major issues that need to be worked out with San Jose- the Balance, the Cable Wrap, and the Panels. We have to resolve all of these issues before we can move on.
Today Brian and Al, the panel pros, worked on trying to align the panels. Although they were able to eyeball it into place, there are two problems. If you look closely, you can see that the panels holes are not symmetric.
Here you can see that there are some interference issues with rods. We will have to come up with a solution, but we want San Jose to look at it first.
Marius and Dave moved into the container to work on the the last 80/20 part, saddlebag #2.
I think that Dave dreams about 80/20 nutplates now.
In case you were wondering, this is where I was to take that last two pictures. I handed Dave the camera, and he caught this rare photo of me. We really are that dirty.
The funny story for today is that my $15 new coffee maker nearly exploded today. There was a faulty switch that popped when I tried to turn it on. Luckily, the circuit breaker worked, and now I am looking for the right coffee maker.
The air conditioner just barely works. It was a cool 78 degrees, although I could swear it was 76. The key was to keep two of windows closed, and to turn on the system at noon.
The PDU is basically ready to go, but there are some lingering issues with the telescope. There are three major issues that need to be worked out with San Jose- the Balance, the Cable Wrap, and the Panels. We have to resolve all of these issues before we can move on.
Today Brian and Al, the panel pros, worked on trying to align the panels. Although they were able to eyeball it into place, there are two problems. If you look closely, you can see that the panels holes are not symmetric.
Here you can see that there are some interference issues with rods. We will have to come up with a solution, but we want San Jose to look at it first.
Marius and Dave moved into the container to work on the the last 80/20 part, saddlebag #2.
I think that Dave dreams about 80/20 nutplates now.
In case you were wondering, this is where I was to take that last two pictures. I handed Dave the camera, and he caught this rare photo of me. We really are that dirty.
The funny story for today is that my $15 new coffee maker nearly exploded today. There was a faulty switch that popped when I tried to turn it on. Luckily, the circuit breaker worked, and now I am looking for the right coffee maker.
Thursday, July 9, 2009
80/20 madness
Another long day at the site, Albert basically finished wiring the PDU. I also had a minor dalliance with another telescope, antenna 5 from the SZA. They kindly let us remove one of the skirts to have a look at the cable wrap. Lots of pictures here if you want to look:
Here is a view of polarbear as seen from the SZA. It is the tiny telescope off in the distant treeline.
I have decided to take the 80/20 catalog away from Marius. He has taken his designs to the depths of interface depravity.
The alignment of the panels is beginning to converge. Brian worked some oh his magic, and looks like we might be on the right track. More to come tomorrow. This is how we left Polarbear at sunset.
On a final note, I had a failed experiment with an air conditioner.
I installed a 8000 BTU window unit into a pre-existing hole in the Control Container. I think we probably need 4X the power, and we dont have a hole big enough. I will look into a more serious solution, but I am worried that by the time I figure it out, it will be fall.
 |
| sza cable wrap |
Here is a view of polarbear as seen from the SZA. It is the tiny telescope off in the distant treeline.
I have decided to take the 80/20 catalog away from Marius. He has taken his designs to the depths of interface depravity.
The alignment of the panels is beginning to converge. Brian worked some oh his magic, and looks like we might be on the right track. More to come tomorrow. This is how we left Polarbear at sunset.
On a final note, I had a failed experiment with an air conditioner.
I installed a 8000 BTU window unit into a pre-existing hole in the Control Container. I think we probably need 4X the power, and we dont have a hole big enough. I will look into a more serious solution, but I am worried that by the time I figure it out, it will be fall.
Tuesday, July 7, 2009
Marius is very dirty
Today, the cable were mostly installed into the wrap. The servo cables are basically all there, and the compressor cables are all in. I am waiting on our science cables until after the servo is mostly done. The elevation wrap looks pretty, although we could not test it due to the imbalance.
The Az looks orderly, but it won't work without the banana or other fix mentioned yesterday. The plan is to check out the SZA banana tomorrow.
This is all that is sticking out of the base of the telescope. There is a new trip hazard, thanks to the servo cable conduit.
Funny story for today- Marius and Dave put up their canopy worthy of a Sultan. The plan was to built the 80/20 parts under the tent, but Marius spent just as much time rolling in the dirt.
This is the messiest I have seen anybody so far. He cleaned up nice for dinner, but reports that there is dirt all over his motel room.
The Az looks orderly, but it won't work without the banana or other fix mentioned yesterday. The plan is to check out the SZA banana tomorrow.
This is all that is sticking out of the base of the telescope. There is a new trip hazard, thanks to the servo cable conduit.
Funny story for today- Marius and Dave put up their canopy worthy of a Sultan. The plan was to built the 80/20 parts under the tent, but Marius spent just as much time rolling in the dirt.
This is the messiest I have seen anybody so far. He cleaned up nice for dinner, but reports that there is dirt all over his motel room.
Back in at the mountain
This is Huan, and I am back at Cedar Flat today. Things are very different after one, week, but the telescope basically looks the same. It seems as though Marius and Dave have the keys to the manlift now, and they are the mirror adjustment crew. Unfortunately, they ran into a roadblock because the rods on some of the panels are not long enough. I am happy to see that I am not the only person who likes to wear a harness.
It looks like Albert and Brian came up with a solution to one of the cable wrap problems, the outer table is now flat to ~40 mils. They did it by putting a thin radial slice in the table and using an angle bracket on the bottom to flatten the plate.
I did not believe I would see it, but Albert fits inside the base.
Dave and Marius are installing half of the Az Cable wrap. We got one side of the cable wrap in, but after it got installed, we discovered another problem, one we were warned we would see. The AZ wrap pulls away from the wall. We were hoping that the compressor cables would provide enough spring force to keep the az wrap along the wall, but it was not. The solution on the SZA was to use a "banana", you will just have to imagine how it works. Albert is checking with San Jose to see what they think.
In the meantime, we started worrying about the inbalance of the boom. There was an earliet problem with the elevation wheel slipping, so Al locked the elevation in place, and it has not been moved in a week. To see if we could bring it close, they hung 1500 lbs of counterwieght off the belly, and it got better, but it is still not totally there. Once again, San Jose is thinking about this.
It looks like Albert and Brian came up with a solution to one of the cable wrap problems, the outer table is now flat to ~40 mils. They did it by putting a thin radial slice in the table and using an angle bracket on the bottom to flatten the plate.
I did not believe I would see it, but Albert fits inside the base.
Dave and Marius are installing half of the Az Cable wrap. We got one side of the cable wrap in, but after it got installed, we discovered another problem, one we were warned we would see. The AZ wrap pulls away from the wall. We were hoping that the compressor cables would provide enough spring force to keep the az wrap along the wall, but it was not. The solution on the SZA was to use a "banana", you will just have to imagine how it works. Albert is checking with San Jose to see what they think.
In the meantime, we started worrying about the inbalance of the boom. There was an earliet problem with the elevation wheel slipping, so Al locked the elevation in place, and it has not been moved in a week. To see if we could bring it close, they hung 1500 lbs of counterwieght off the belly, and it got better, but it is still not totally there. Once again, San Jose is thinking about this.
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