Venus Becomes a Crescent

Even when Venus is high in the sky and well placed for observation I will seldom take the effort of turning a telescope towards the planet. Why? Because Venus is pretty boring to look at. Perpetually cloud covered it has all the detail of a cue ball. It is a white disk with nothing of note to be seen. Yeah, pretty boring. Now turn the telescope to Jupiter.

Crescent Venus
Venus approaching inferior conjunction, 24Dec2013
One exception to this occurs when Venus is approaching, or just emerging from inferior conjunction. As the planet passes between the Earth and the Sun we are looking at the nighttime side of the planet, with only a little of the daytime side to be seen. As a result Venus will appear as a brilliant crescent.

This begins as the planet passes maximum eastern elongation, about two months before inferior conjunction. At this point the planet is seen from the side with respect to the sunlight, the planet will be about half illuminated. In the weeks after maximum elongation the planet will appear ever more crescent.

Venus 28May2012
Venus on 28May2012, about 12°44′ from the Sun
The last weeks before conjunction, as Venus is very low in the sunset, or the first weeks after conjunction as it sits very low in the dawn are the most interesting. During this time the planet is a very fine crescent, quite a beautiful sight in the telescope. Many observers, including myself, have made a point to observe Venus at this time, the one time this planet really becomes interesting to view.

Imaging Venus in the Daytime
Imaging Venus in the daytime a mere 12°44′ from the Sun.
As the planet is quite low in the sky it makes it a challenging telescopic target and distortion by the atmosphere can be troubling, blurring the view.

It is possible to enjoy this sight in the daytime, while the planet is high in the sky, the seeing can be better and the view sharper. Of course this also occurs when the planet is near the Sun, thus extreme caution should be practiced at the telescope to avoid any direct sunlight and possible eye damage.

Planetary Drawings by Galileo
A page from Galileo’s 1623 treatise The Assayer—Il Saggiatore
The phases of Venus are quite interesting from a historical standpoint. The phases of Venus clearly show that the planet revolves around the Sun. The phases were one of the primary arguments used by Galileo in his treatise The Assayer—Il Saggiatore published in 1623, where he lays out many of his ideas on science itself and how observation and experimentation should be primary.

While the the evidence challenged prevailing ideas of the time, some astronomers attempted to explain the phases of Venus by any other means to preserve their Earth centered universe, which led to rather tortured models of planetary motion. But it was clear to most that Galileo was right, the simple and elegant answer was that the Sun lay at the center. The orbits of Mercury and Venus, the phases, along with other observations like the moons of Jupiter, were hard evidence that few could ignore.

In 2017, eastern elongation occurred on January 12th. By now Venus has begun to show a substantial crescent, about 30% illuminated if you look today, Feb 12th. Over the next few weeks as the planet sinks into the sunset, the crescent aspect will thin dramatically.

By the end of February the planet will be only 17% illuminated, another week after that it becomes only 11%, by which time the planet will be difficult to spot in the sunset. Inferior conjunction will occur on March 25th. A couple weeks later and it will be possible to spot the planet in the dawn and observe the now thickening crescent.

Venus Events for 2017

  Date UT Separation Mag
Maximum Elongation Jan 12 47.1°E -4.4
Inferior Conjunction Mar 25    
Maximum Elongation Jun 3 45.9°W -4.3
 
Source: NASA Sky Calendar

ATM Gallery

2017 Cherry Blossom Festival Star Party

Cherry Blossom Festival is a huge event where a large segment of the island population descends upon Waimea for a day of celebration. there are booths and events all across town. There are cultural demonstrations, cooking demonstrations, performances, and lots of food available for an all day, all town festival.

Solar Viewing
Viewing the Sun at the Cherry Blossom Festival
With most of the parking on the south side of Keck observatory, the shopping mall parking lots, and the main event venue north of Keck at Church Row where the cherry trees are, a huge number of people cross the observatory lawns on their way to the festival. It is a natural fit for us to use the day for an outreach event.

The festival is also a very local event. Sure there are a few tourists drawn to Waimea for a festival. But, by and large this is a local event, the majority of attendees are island residents.

Continue reading “2017 Cherry Blossom Festival Star Party”

Hawaiian Enough?

As the TMT contested case drags on we continue to watch. Thanks to the efforts of the staff of Nā Leo TV the entire proceedings are streamed live. Several of the latest witnesses for the University are Hawaiian supporters of the telescope project, it is these voices that I am most interested in hearing.

Retired Judge Riki May Amano
Retired Judge Riki May Amano presides over the TMT contested case hearing
It is when the questioning begins that things get ugly. Question after question challenges the integrity of the witness. The questions challenge their personal values as if to say “You are not Hawaiian.” Over and over the questions were repeated, each successive question designed to attack the cultural identity of the witness…

“Where did you grow up?”
“How old were you when you learned that?”
“Who taught you that?”
“When was the last time you were on Mauna Kea?”
“When did you last worship on Mauna Kea?”
“Where did your family worship?”
“Do you pray to Poliʻahu?”
“Who are the parents of Poliʻahu?”

Continue reading “Hawaiian Enough?”

Some Chinese Eyepieces

A Celestron FirstScope in need of eyepieces. Time to find a couple inexpensive eyepieces. With the telescope destined for an eight year old girl I really did not expect the eyepieces to live up to any demanding standards. But neither do I want the views to be truly horrible either, it would be nice if the telescope is properly enjoyable.

Chinese Eyepieces
A set of cheap Chinese eyepieces
Thus I went to the source of cheap optics and found a set of Chinese eyepieces on eBay that might just do the job. For $22 they were the right price. The set includes three eyepieces, a 23mm, a 10mm and a 4mm for high power, a nice selection of focal lengths. The right price, but how about image quality?

As the eBay sale is from a US seller the eyepieces arrive in just a few days. Unpacking the eyepieces is the first pleasant surprise… The quality is not bad, metal barrels, decently molded rubber bits, decent looking glass. An ebay sale often a bit of a gamble, but this does not look bad at all.

Continue reading “Some Chinese Eyepieces”

A Celestron FirstScope

I tend to end up with telescopes, they just appear on a semi-regular basis, given to me with the instructions to find a home for them. One of the latest additions to Andrew’s Home for Wayward Telescopes (AHWT) was a Celestron FirstScope. It was bequeathed to me by a co-worker moving to the mainland and thus dwelt for a time in my office, there being little room in my garage for yet another telescope.

Celestron FirstScope
A Celestron FirstScope in somewhat larger company
This telescope is now headed to a new home. With Christmas approaching another co-worker asked my opinion in buying a telescope for his eight year old daughter. She had expressed interest and he was wondering what to get. Quick to size an opportunity to divest myself of an unused telescope I let him know I had just the thing! One less mirror to clean. Rob of course was quick to seize on the idea of free.

Continue reading “A Celestron FirstScope”

Alone with the Mountain

Several times during the recent contested case hearings I have listened to telescope opponents ask witnesses on the stand and under oath, “Have you asked the mauna?” or “Have you asked Poliʻahu?” I have heard a dozen variations on the question, but that is the general sense of it. They are asking if the witness has asked the gods or goddesses who are reported to dwell on Mauna Kea if building the telescopes is allowed. Poliʻahu in particular, the goddess of snows and ice, is identified with the summit of Mauna Kea.

Summit and Winter Milky Way
The winter Milky Way over the summit of Mauna Kea
The question strikes a particular resonance with me, returning to my thoughts again and again. I consider my relationship with the mauna, is it pono that I continue to work at an observatory and support the construction of TMT?

I think of all the nights I have spent alone on the mountain. So often I have sat in the quiet, with nothing but the mauna and the stars. Sometimes I am sitting beside a small telescope, and taking a break to simply enjoy the night. Sometimes I am waiting for a camera, somewhere nearby in the dark. Sometimes I am just sitting doing nothing at all, simply enjoying the beauty of this place. In any case I am alone with the silence, the stars, the mountain, and my thoughts.

Continue reading “Alone with the Mountain”

Modding the HBS

Just checking to see if I got the wiring right. Some modifications to the telescope HBS, Hydraulic Bearing System, to allow for a slower startup. Some new hydraulic valves installed by Mark, a few new relays added by me, and the job is done. Hopefully less sputter and spitting on startup to keep the oil off the drive tracks. The system is a classic relay logic controlled setup, seriously old-school.

Modifications to HBS
Just checking the wiring in HBS