Postcard from the Universe – Double Cluster
Category: Astronomy
Exploring the cosmos
The Moon and Saturn
Tomorrow morning, Feb 21st, the Moon will be in close attendance with Saturn, separated by a little under 4°. The two will be high in southern the sky before dawn, a last quarter Moon will be 61% illuminated. Saturn can be seen as a 0.5 magnitude object just East of the Moon and west of the head of Scorpio. The following morning, Feb 22nd, the Moon will have moved to the other side of the ringed planet with a separation of just over 8°.
Viewers on the other side of the world will be able to see a very close pairing of the two, less than half a degree apart or even in occultaion depending on location. Close approach will be about 14:00 HST on the 21st. You could make an attempt to view the pair in the daytime sky, Saturn is bright enough to be seen next to the Moon in a modest telescope or even a good pair of binoculars. Unfortunately the Moon sets around 11:00, a few hours before close approach here in the islands.
Staying Late at Work
The plan was simple. Stay on the summit after work to do some nighttime scenic photography.
I was hesitant in going up after suffering my recent ear infection. The ear is vastly better, no problems with clearing the ear for several days. After two weeks absence the list of things I needed to get done on the summit was getting lengthy and urgent. Yet I worried a bit about going up. An idea… Take my own vehicle. If I have trouble I can go at my own pace without holding up the rest of the guys. If the trouble is serious I can abort and head back down.
If I did bring my own vehicle I could get in a little photography along the way. I had not really had a chance to try out the Rokinon 14mm f/2.8 lens I had bought specifically for starry sky work. Why not stay late, watch sunset and take a few photos after dark? There is snow on the summit, the weather looked promising, the Moon would not rise until after 10pm, all good things.
The plan worked as envisioned. A good day getting stuff done. Actually a rather hectic day. The filter wheel problem of TRICK found and eliminated, the heater circuit at least looked at, I think the problem is still there. Warping data recorded for a segment in Keck 2 for the refurbishment project. Some wiring on TBAD completed, still more to do. An issue with the Keck 2 interlocks that popped up during the day was dealt with. Yes, a very good day.
A minimal dinner of instant ramen, and some paperwork accomplished while waiting for sunset.
Into the cold dark I go… The combination of the Canon 6D and the fast 14mm lens is impressive. This gear will really allow me to step up my game. I was able to shoot great material under very dark conditions. Photos that had been just out of reach for me until now. It will take me a couple days to go through and process the material, but a first look is very pleasing.
Only one problem… What is this red stuff showing up in my photos? Normal airglow is green, but this is crimson red and has very distinct structure? The idea of aurora crosses my mind, almost immediately dismissed as I am standing at 20°N latitude. I step away from the camera and the light for a bit. With some effort I can convince myself that I am seeing red in the sky, at least in the darker areas away from the Milky Way. But it is fleeting, and perhaps just an overactive desire to see something.
I get home and just out of curiosity I check the planetary Kp index… What?!? We have a Kp=6 geomagnetic storm in progress! Beautiful aurora photos are being posted from the upper midwest. Reports of aurora from across much of the United States. There is certainly a dramatic storm in progress. Perhaps this is a low latitude auroral glow!
There are some references to auroral glows detected at all latitudes during strong geomagnetic storms. Is this what my camera is detecting?
It is a nice photo. You can see the glow from the lava lake at Halemaʻumaʻu, the winter Milky Way, and a research laser shining straight up from the atmospheric lab atop Mauna Loa.
Postcard from the Universe – First Quarter
Mercury at Inferior Conjunction
Today the planet Mercury passes through inferior conjunction, passing between the Sun and the Earth. In a week or so the planet will again be visible in the dawn sky, climbing higher each day. Maximum elongation will occur March 13th.
Full Moon
A Lecture and a Star Party
If you did not make a point to come to the last Keck lecture you missed a fun night.
Greg did a very nice job of explaining spectroscopy. this is never easy, the details can get pretty technical. Making sense of spectra while talking to a general audience is a neat accomplishment. This is even worse when you are talking about the spectra of water in the near infrared where there are thousands of emission lines. Good graphics and a step by step explanation worked, animations of dancing water molecules, and dancing Greg not withstanding.
When the crowd poured out we were ready. A lot of folks stayed to view, and five ‘scopes were in operation to meet them. I have to give thanks to Tony, Chris, Rickey, Cliff, Bernt, and Purcynth, who manned the scopes and answered the flood of questions. As we were breaking down the clouds were rolling back in, very good timing indeed.
The lecture was recorded and should show up on the Keck website soon. I’ll try to post a link to it when it does appear. In the meantime, if you have not already done so, get your email on the Keck Nation list so you know about these events before they happen.
Getting Focus Right
Focus is one of the most frustrating problems when shooting in the dark. The number of astrophotos ruined by poor focus is legion. Worse, the problem is often not found until afterwards, when hours of effort have been wasted. Very slight errors in focus can spoil an otherwise great photo.
Taking photos in the dark creates a situation where the normal solutions do not work… Autofocus simply will not operate without enough light. Taking the lens off and attaching the camera to a telescope results in a completely manual focus. Simply focusing through the viewfinder is not accurate enough.
Do remember to switch off the autofocus feature of your lens. Once you get focus set correctly you do not want to lose it the moment you touch the shutter button. Not that I have ever done that… Never? Well, perhaps maybe.
The Moon and Jupiter
Tonight the Moon and Jupiter will be quite close. The pair will rise at nearly the same time, about 15:09HST, placing the two well up in the eastern sky by sunset. The Moon will be quite large, 87% illuminated and about 5° from the bright planet.
With Jupiter this close to the Moon it is an excellent time to see Jupiter in the daytime sky. Look 5° north of the Moon for a bright pinpoint of light. 5° is ten times the size of the Moon seen in the sky, north will be to the left seen as the pair rises above the eastern horizon.
Seeing Planets in the Daytime Sky
We expect to wait until darkness falls to observe the stars and planets. While the Sun and Moon are normally seen in the daytime sky, there are other objects that may be observed.
Both Jupiter and Venus are bright enough to see fairly easily in full daylight if conditions are right. Saturn can be observed with a telescope if you can locate it. Very occasionally, we are treated to a daytime visible comet.
Jupiter and Venus are the easiest, you simply need to know where and how to look, but once glimpsed they are fairly easily seen. It is the knowing how that makes it possible. Try these simple hints…
- Try when the planets are far from the glare of the Sun, in the first hours after dawn or last hours of the day are best.
- Clean air is necessary. If the air is hazy, dusty or smoggy it will hide the planets from view, particularly when near the Sun. There will just be too much solar glare to pick out the planet. For the same reason try when the planet is high in the sky and you are looking through much less air.
- The human eye will relax and defocus if there is nothing to focus on. This happens when looking at a plain expanse of blue sky. You could be looking right at the planet and not see it. A few puffy clouds around, or better yet, the Moon, will give the eye something to focus on, allowing the planet to be easily seen.
- Put the Sun out of sight to reduce glare. Simply position yourself in the shadow of a tree or building to get a better view.
- Pick a day when the Moon is near the object you are looking for, it will provide a simple signpost to the correct location.
It is this last hint that can be particularly useful. Looking ahead with the aid of a planetarium program you can find a day when the Moon is near the planet. Using the program to estimate the position with respect to the Moon you can look in just the right place. If you get it right the planet will appear as a bright star-like object. Once you see it you will wonder how you ever missed it in the first place.
Have a try.