Meanwhile in Hawaiʻi…
Category: Astronomy
Exploring the cosmos
Mercury Appears in the Evening Sky
The planet Mercury is starting an evening apparition. The planet should become visible this week just above the fading glow of the setting Sun as a magnitude -1 object. Currently about 10° from the Sun it will rise higher each evening, reaching a maximum elongation of 18° on February 16th.
Climbing the Stairs
Wait! What is broken?!?
The elevator.
It has been broken for two days. The contractor is here to fix it, but this is the day Olivier and I need to get a job done in AO. It would have to be the Keck 2 elevator, not the Keck 1 elevator. Which telescope are we working in today? Keck 2 of course.
This will mean climbing the stairs to the Nasmyth deck, all five flights of stairs. Five flights does not sound too bad, until you remember that the bottom of these particular stairs start at 13,600ft above sea level. Climbing these stairs is guaranteed to get your heart pumping and remind you of the consequences of every one of those 13,600ft.
The job? Re-installing one of the mirrors in the rotator that was re-aluminized earlier in the week. A delicate, fiddly job that would take much of the day. There will, of course, be missing parts, needed tools, or other small things that we will have to get during the course of the job. Things that are at the bottom of those stairs.
Every trip up and down would be planned, this is not the time to remember that you also needed an #8-32 nut, after the climb. No forgotten items, everything thought through twice. We got the job done, a critical bit of optics safely secured back in the mount and correctly aligned.
In the end I only had to climb the stairs five times through the day.
That was quite enough, thank you.
</rant>
Soldering Small
It is always another little problem. But, on occasion, a problem is an excuse to have a little fun while getting the job done.
Enter an old WYKO interferometer with a composite video output. The gear is a critical piece of kit used to monitor the deformable mirror used in the adaptive optics system. The images from the interferometer are analyzed by a windows PC with special software. Windows, as in Windows 98!
Updating this computer has been on our to-do list for way too long. Time to get it done… When installing the new computer and video board to update this system I found that the video quality was quite bad. It would tear about halfway down the image, something wrong with the horizontal sync? Looking back it was not great on the old system, but usable. On the new system it was just not going to work.
Full Moon
Testing TBAD with UAVSAR
So we have a system that will detect aircraft and shutter the laser.
In theory TBAD will detect the TCAS transponder on an aircraft, turning off our AO Laser to avoid illuminating the aircraft. This work via means of a directional antenna mounted to the front of the telescope that is able to detect the 1090MHz TCAS transmissions from the aircraft. The system has been operational for the better part of a year, mounted to the Keck 2 telescope. It operates all the time, whether or not we are using the laser.
The problem is that there is very little air traffic over the summit, it is even more rare that a plane goes directly in front of the telescope while we are observing. It is these test cases we need to prove the system, an aircraft passing through where the laser would be. Though the first year of running the system we logged a total of one detection that would have resulted in a laser shutter event. We need more test cases if we are to prove to the FAA that the system works as designed.
The Moon and Jupiter
This evening sky-watchers will note Jupiter directly beside a bright Moon. The pair will be very close separated by only 1°09′ as of sunset here in Hawai’i. Accounting for the radius of the Moon this will mean that the planet will be only 55′ off the limb of the Moon.
Observers further east and south will be able to see an occultation, with the Moon passing in front of Jupiter. Here in Hawai’i the occultation will be over before sunset. It is no use observing during the daytime either, as the planet will pass north of the Moon for our latitude.
The proximity of the two does provide a nice opportunity to see Jupiter in the daytime, as the Moon will provide a signpost to the location of the planet. The pair will rise about 14:00HST and be well up before sunset. Look just to the north of the Moon (left as they rise) for a pinpoint of light. At -2.6 magnitude the planet should be easy to spot as long as the sky is clear and not hazy.
Shift a Little Weight
The trade-winds have returned for the evening. And while they are welcome for the comfortable temperatures they bring, the winds are unwelcome for the problems they create at the telescope. I am trying to get in one last exposure sequence for the evening, but the guider graph shows trouble. There are constant errors, not small errors either. The Right Ascension axis seems to be the issue, with errors of +/-3 pixels on the guider. This is just not going to work.
I watch the graph for a while, trying to figure out what I can do. I have had an issue where the guide star was the source of the problem, two stars to close together, a double star I did not notice when selecting my guide star. I stop the guider and select another star… The problem continues.
As I feared, my problem is most likely the wind this evening, a continual issue on this rock I live on. A speck in the middle of a very large ocean, the winds are a fact of life here. I only shoot with small telescopes, less sail area to catch the wind with a short tube. A TeleVue 76mm, an AT6RC, or simply a wide angle camera lens. The smaller scopes provide less loading for the old Losmandy G11 I mount them on.
I decide to try something else, shifting the balance to load the RA gear down. I gently slide the counterweight down the shaft about an inch. There is barely a blip on the guider as I make the adjustment. Better yet the guide error graph settles down! Looks like I will be able to get in a few more exposures before putting the ‘scope away.
Postcard from the Universe – Comet C/2012 K5 (LINEAR)
Another product of imaging earlier this week. Comet C/2012 K5 (LINEAR) is fading, but still bright enough to image. Right beside Orion it was well placed to target from my driveway. Just refreshing my comet hunting skills, getting ready for the show over the next few months as C/2011 L4 (PanSTARRS) comes into view.
Postcard from the Universe – NGC1365 and Supernova 2012fr
A photo taken from my driveway of NGC1365 and supernova 2012fr. It is a bright supernova in a classic barred spiral galaxy. I had observed NGC1365 in mid-October with the 18″, noting the beautiful spiral structure. The supernova appeared about two weeks later. I have since observed it in a couple telescopes, including Cliff’s 24″.
The nova seems to be fading now, it peaked around 12th magnitude in November. Currently about 14.5 magnitude, but still easy with the AT6RC and Canon 20Da camera.
