Observing Opportunity for Comet 41P/Tuttle-Giacobini-Kresak
There may be a nice opportunity to view Comet 41P/Tuttle-Giacobini-Kresak in the next few days as the current Vancouver forecast calls for partially clear skies from Sunday, April 2nd to Tuesday, April 4th.
This comet is now as bright as 6.5 mag and may brighten even more as it gets closer to the Sun. The comet is closest to Earth on April Fools’ Day, about 21.2 million km away, the closest approach to Earth since its discovery. The comet’s perihelion point, where is it positioned closest to the sun, occurs on April 12th.
It is in an excellent position for observing: near the constellations Draco, Ursa Minor (the Little Dipper) and Ursa Major (the Big Dipper). The comet is quite diffuse but should be visible with binoculars and small telescopes.
41P makes a trip around the sun every 5.4 years, coming relatively close to Earth on only some of those trips. The comet is a member of the Jupiter class of comets. A NASA team will be observing 41P on April 1 using the Infrared Telescope Facility in Hawaii. Because comets formed early in the solar system’s history, Comets that come close to the Earth give scientists a chance to deepen our understanding of the processes that led to the formation of our planet.
“An important aspect of Jupiter-family comets is that fewer of them have been studied, especially in terms of the composition of ices in their nuclei, compared with comets from the Oort cloud”, said Michael DiSanti of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
A Surprise Brightening of Comet C/2017 E4 Lovejoy
Comet C/2017 E4 Lovejoy was only expected to reach 9th magnitude at its brightest in mid-April but it has already reached 7th magnitude and it’s more condensed and is easier to see. E4 Lovejoy is located in Pegasus, in the east just before dawn. Recent images show a small ion tail. A Sky and Telescope article has images and more details.
NASA has made a poster of the the TRAPPIST-1 system available following their announcement on the discovery of the first known system of seven Earth-size planets around a single star. In this system, called TRAPPIST-1, all of the planets are likely to be rocky based on their densities. Further, three of these planets are located in the habitable zone the where a rocky planet is most likely to have liquid water.
The TRAPPIST-1 star is classified as an ultra-cool dwarf and all seven planet orbits are closer to their star than Mercury’s orbit is to our Sun. The planets are also close to each other; to an observer on one of the planet’s surface, the others would appear larger than the moon our sky.
Suzanna Nagy’s article on “What Kind of Telescope Should I Buy?” in the Sept/Oct 2016 edition of our Nova newsletter praised the Dobsonian design. A Dobsonian is a type of reflector telescope that uses two mirrors. Suzanna’s article listed several advantages of the Dobsonian design. However, a recent edition of XKCD has revealed a little-known deficiency of a reflector.
Our public relations coordinator, Scott McGillivray, talked on Global TV about Saturn and the Cassini mission, Orbital ATK missions that launch rockets from planes, making plans for the Solar Eclipse on Aug 21, 2017 (eclipse map), and image processing of raw Juno data.
Scott’s segment on Saturn and Cassini is a good lead in for the Paul Sykes Lecture on Jan 21st at 7:30pm at SFU’s Burnaby campus: Going out in a Blaze of Glory: Cassini Science Highlights and the Grand Finale
Cassini will send back its final bits of unique data on September 15, 2017 as it plunges into Saturn’s atmosphere, vaporizing to protect tiny Enceladus, one of Saturn’s ocean worlds. Come and hear the story of recent science discoveries and the upcoming excitement during the final orbits. Dr. Linda Spilker, Cassini Project Scientist, will present highlights of Cassini’s ambitious inquiry at Saturn and an overview of science observations in the final orbits.
A couple of new weather satellites were launched this past fall.
GEOS-R (GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITE – R SERIES) launched in November and is the first of a set of four new satellites operated by NOAA and NASA. These satellites will all be placed in geosynchronous orbits. A satellite in a geosynchronous orbit matches the rotation of the earth so the satellite seems to stay in place over a single longitude, though it may drift north to south.
The GOES-R satellite will provide imagery and atmospheric measurements of Earth’s Western Hemisphere, total lightning data, and space weather monitoring to provide critical atmospheric, hydrologic, oceanic, climatic, solar and space data. Once fully deployed, the new generation of GEOS satellites will be able to image the entire continental US every 30 second and collect three times more data and images with four times more resolution.
The GEOS satellites also provide satellite aided tracking for search and rescue operations. The satellites can be used to quickly detect and locate signals from emergency beacons onboard aircraft, vessels and from handheld personal locator beacons.
GOES-R is undergoing a year long checkout and validation phase. So far the satellite is stable and performing very well.
CYGNSS (Cyclone Global Navigation Satellite System) launched on Dec 15, 2016 from a Orbital Science Corporation Stargazer aircraft. CYGNSS is a constellation of 8 micro-satellites that will be placed in a low-earth orbit. The more detailed wind speed data from CYGNSS will allow scientists to better see inside tropical storms and hurricanes. The complete constellation will provide nearly gap-free Earth coverage with a median revisit time of three hours over the critical latitude band for tropical cyclone formation and movement: 35° North latitude to 35° South latitude.
Clear nights have been rare this fall in the Vancouver area. In October, we set a record for rain on 28 out of 31 days while normally there are about 15 days of rain. November was not better with 25 rain days – the 4th most rain days for November. But I took advantage of a recent clear night last Wednesday (Dec 7th) to get in some imaging of the Moon and the Pleiades.
The cool weather presented some challenges. At -3°C, the temperature was slightly below freezing but quite manageable for me with a good jacket, boots, and gloves.
My equipment didn’t fare as a well.
The first problem became apparent when I went to polar align my mount. I built a concrete pier topped with an aluminium adapter last summer but had removed the CGEM mount head during the two months of rain. So I reattached the mount head and stuck my 80mm Esprit refractor on it early to allow it to cool down. A couple of hours later, I went to polar align the mount and found that I could not adjust the azimuth at all: a thin layer of frost and snow on the adapter likely froze the mount head to the adapter and prevented it from moving. Poor polar alignment meant that I would have to use short exposures for imaging – not a problem with the moon at all and I could try stacking lots of short exposures for the Pleiades (lucky imaging).
I powered up the CGEM mount (it is a goto mount) and looked at the LCD hand controller to work through the initialization procedure. The second line of display on the hand controller appeared garbled and unreadable – apparently, LCDs are sensitive to temperature as the fluid tends to “stiffen” in the cold. I managed to get through the initialization and start tracking mostly by pressing “enter” to accept the defaults but decided to manually slew the mount rather than trying to do a star alignment and using the goto capabilities.
Finding the moon was easy, and I managed to take a few images though the camera battery only lasted about ½ an hour in the cold. Fortunately, I had a spare battery charged and ready to go for the Pleiades.
Finding the Pleiades was more difficult. The Pleiades are an easy naked eye object even under normal city light pollution. But my yard in Coquitlam was still covered with 10-15 cm snow from the previous day. It was amazing how much light reflected off the blanket of snow and made it difficult to spot the Pleiades. I did manage to find them after a few minutes of random hunting – thank goodness the 80mm Esprit has a wide field of view!
I ended up getting 45×15 second sub-exposures of the Pleiades but, as a final insult, part way through my imaging, the neighbours decided that the cool night was a good time to use their outdoor hot tub and turned on a bunch of bright exterior lights that shine into my yard. Ah well, I still stacked and processed the sub-exposures to get an image that shows some of the nebulosity around the Pleiades.