Had a night of very good seeing recently, and imaged this collection of (mostly) interacting galaxies.
We get a chance to take images of stuff now and then with the one-meter. We are in the testing and deployment stage – installing and testing new hardware, and integrating it into the telescope software control.
Currently we are working on the guider assembly. But we found time to take an image of a small portion of the Pelican nebula.
This image illustrates the low-noise capabilities of our Princeton Instruments Pixis camera. This is a small stack of 3-minute images (short exposures since guiding isn’t working yet). Shot through an H-alpha filter and processed in PixInsight.
Our telescopes in Australia generated images today of Mars and comet Siding Spring as they were moving closer together. This is an image taken with the Canon 7D on the Takahashi Epsilon 180 f/2.8 telescope. Comet is near center of the field of view; Mars is very bright, it is the blown-out big-old bright spot.
Click image for full size version.
We were imaging with the one meter while testing setup of the guider assembly recently. I had a chance between tests to take a few 3-minute images of Stephan’s Quintet and stack them to see what we could get with the old (and damaged) secondary.
So, yes, we are still waiting on the replacement secondary. It’s still in polishing, down to about quarter wave quality RMS so far.
But even with a damaged secondary, we got a good image. Seeing was right around one arc second, ranging from 0.9″ to 1.2″ that night.
This is a stack of eight 3-minute images.
The observatory code for our telescopes at Siding Spring Observatory (in the iTelescope.Net roll-off) is Q62.
The blank for the new secondary has now been manufactured, and delivered to the polisher for evaluation. Once we are sure that the blank meets specifications, figuring and polishing will begin.
We expect that to take about 3 months, give or take a few weeks either way.
While we wait for the new secondary, we will be completing work on the guider assembly, and updating/adding various features and systems so that we will be ready to go when the new secondary arrives.
A new secondary for the one-meter is being made. We started that process about a year ago. We have continued imaging with the flawed secondary, but recently we had to ship the old secondary to the polisher so that it could be used to validate the test setup for the new mirror. We are unable to operate the telescope until either the old one is made available again, or the new one is completed.
The work on the new secondary has been very involved. (The original has a dimple and must be replaced.)
First, the mirror itself is a complicated thing. It’s a ribbed silicon-carbide mirror. It is ultra light in weight, and very rigid. These qualities are important because the secondary is a high-speed tip/tilt corrector: it sits on a very fast tip/tilt table from Physik Instrument, and will be able to make AO corrections at up to 100 times per second.
That last bit turned out to be a big deal for making a replacement. Again and again, as the manufacturer tried to machine the raw materials into the required shape, the mirror blank would shatter – it was too thin. The problem was that we had to find a way to make it stronger without making it any heavier.
So we moved things around. The ribs were made fatter, but shorter. We then had to do FEA (finite element analysis) on the new design to discover its resonance frequencies, and make sure that none of them were in the range of the operating frequencies, or in a close harmonic with them. Basically, we had to make sure that any resonances were > 300Hz.
That all took more than half a year. The redesign went manufacturing late this summer, and is finally nearing completion. The substrate has been machined and hardened, and will be coated with the polishable material via CVD (carbon vapor deposition). (We need to measure the substrate very precisely before and after coating, so that we can make sure the coating is thick enough to contain the final curvature of the mirror surface. That’s another few weeks right there!)
Once the mirror goes to polishing, it will be another three months before it’s completed and shipped to New Mexico. At that point, we’ll mount it up and begin commissioning of the telescope. At that point, we will have finished up all systems, and it’s only a matter of making them all behave properly. We’ll be open for business shortly after, but it’s fair to say that during the first year of operation, we will be honing our skills, writing software to make use of the more advanced systems, and otherwise perfecting operation.
Here’s a photo of the mirror, after machining and before it has been coated with the CVD layer.
The supernova sn2013ev is the bright spot in the supper arm of IC1296, shown below at 200%:
The stages are back, and we have tested them; all is (mostly) well. I (Ron Wodaski) am currently writing the software to control the stages for positioning the pick-off mirror. The software is well along and will be tested over the next week or two.
We are still working to get the replacement secondary mirror for the one-meter telescope. The blank was nearly done, but cracked. We are reviewing the design to see if we can make it easier to manufacture, then we’ll have another made, and move on to polishing about three months later. So it’s going to take a while to get the mirror completed.
We are still using a video camera for guide testing; that limits what we can do due to limited sensitivity. Eventually, we’ll acquire a sensitive CCD camera for guiding.
The tip/tilt (similar to AO guiding from SBIG and others, but at much much higher speeds) setup has undergone initial testing. It’s going to be reconfigured in the near future, and then we’ll work on implementing it for use in imaging.
Here is a recent image of NGC 4217 taken during testing of guiding. It’s a single 10-minute image.
- We had a failure of the X/Y stage that holds the guider, and those parts have been sent to the manufacturer for service. They should be back sometime in January. That doesn’t prevent operation, but we can’t work on the autoguiding software development until these parts return.
- The Princeton Instruments Pixis camera is still out for repairs. The main board and TEC cooler are being replaced. In addition, the length of the camera is being shorted so it can accommodate the pickoff mirror for guiding in the imaging setup. We are also switching it from water-cooled to air-cooled; the cooling unit failure was a consequence of a failure in the water circulator. We want to prevent that from happening again, as it’s an expensive repair. We will use a fan to make sure waste heat does not get into the optical path. This does prevent operation until the repair is completed. (We have other cameras, but they are research-oriented, and not really useful for imaging purposes. The Pixis is ultra-low noise, and is ideal for imaging.)
- The replacement secondary mirror is continuing to progress – the blank should be ready this month or next, and we will be putting out bids for polishing the blank this month.