From my recent diary

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Wednesday, December 21

This month I comet hunted only once at dusk on Dec. 13. At that time I expected I could comet search over 1 hour, but I could only 20 minutes due to sudden cloudiness. I am afraid that we cannot expect clear sky this month here in Niigata.

I enjoyed SOHO image of C/2011 W3 that was discovered by Terry Lovejoy. He discovered this comet using CCD but was discoverable visually in the southern hemisphere. We were worried that the comet would have disappeared at the time of the perihelion passage as it is a small size, but it survived! Unfortunately, we cannot observe this comet from Japan. I expect an appearance of a great comet: hopefully armaturefs visual discovery.

Wednesday, November 23

The percentage of cloud cover was high, but I saw some gaps in the sky and I went on comet hunting. I set up my comet-seeker at 3:44a.m. and first of all I enjoyed observing C/2010 G2 Hill. I trained my telescope at this comet using Starmap Pro, iPod app, instead of the digital setting circles. The comet was near Iota, Aurigae, and it was easy to spot. It was 11th magnitude.

While I was observing C/2010 G2, almost the entire sky was covered with cloud. I had been waiting in my car around one hour, there appeared some gaps among the cloud. I searched the constellation of Virgo, but I was clouded out again in 10 minutes. I wondered if I took down my comet-seeker. At 5:05a.m. the time when the twilight began, starry sky spread around Corvus and I comet hunted till 5:30a.m. After all, I swept the sky only for 45 minutes through thin cloud. Even so, I could identify 4 galaxies with magnitudes of 10-11th. This was my third comet hunting session this month, but I could do it satisfactorily only on November 2 due to the cloud.

When I was about to finish the session, thin moon with the earthlight, Spica and Saturn were shining together. These objects along with Corvusfs quadrangle formed well balanced geometric pattern. I felt happiness to take a look at this scenery, though the comet hunting session was interrupted by clouds and unsuccessful.

Tuesday, November 2

I comet hunted two consecutive predawns. I aimed my telescope at M65, M66, and NGC3628, \all of them were seen in the same FOV, and began to search from there. I identified many galaxies one after another. Sometimes several galaxies came into the same FOV. If this was the case, I could not identify them all using the digital setting circles due to lack of the resolution, and forced to open Uranometoria 2000 Atlas to check them comparing positional relation among stars and galaxies.

However, the situation has been different since last week. I purchased iPod (8GB) and downloaded Deep Sky Browser (DSB). This app makes it possible to download Digital Sky Survey (DSS) images, e.g. NGC, IC and UGC catalogs. You can set the size of the image 5'x5', 10'x10', 30'x30', or 60'x60'. iPod requires WiFi environment to download the images and you need to do at home.

An image of galaxies displayed on iPod using Deep Sky Browser. From the top to the center NGC4564, 4567, 4568. The image is 30' wide.

When I come across some galaxies in the same FOV, firstly, I identify one of them using the digital setting circles (DSC). Secondary, I display that galaxy using DSB with the image size of 30'x30', or 60'x60' so that all the deep sky objects around that galaxy can be identified. It is interesting to use DSS images as you can see the structure of the galaxy that you cannot clearly recognize by visual observation. In fact I thought NGC4567 and 4568 (above) were one galaxy at a first glance, but I found it consisted of the two to see DSS image. Once I knew the feature I could recognize two galaxies by visual observation. This predawn, I enjoyed comet hunting using this gadget, and identified 44 galaxies.

Another app, Starmap Pro contains full catalog of NGC and IC. As for stars, it includes SAO, Tycho 2,  HD and Hipparcos catalogs, and you can download orbital elements of comets.

Both the apps are very handy and convenient that makes comet searching more exciting. I use red-colored plastic plate for night vision.

Honda-Mrkos-Pajdusakova is displayed using Starmap Pro.
Left: wide area; right: 68x, 1.3 degrees FOV. The magnification is shown as 67x since round-off is not applied.

Saturday, October 22

Today last week, I attended the Oriental Astronomical Association (OAA) General Assembly in Tokyo where I received a certificate of merit for the discovery of C/2010 V1 Ikeya-Murakami from Tsutomu Seki, the president of OAA. I have never imagined that Ikeya became a co-discoverer and that received the award of merit from Seki. It is a staggering event.

I was receiving the certificate of merit from Seki. Photo by Hirohisa Sato.

I have also received an award from the Astronomical Society of Japan, but could not attend the ceremony in Kagoshima, Kyusyu Island, as the schedule was not suitable for me. Originally, the ceremony would have been held in Tsukuba, north of Tokyo, but it was canceled due to the earthquake.

To change the subject, the forecast said it would be clear sky for three days from Wednesday through Friday and I got up in wee hours three consecutive predawns. Actually, it was clear sky only on Thursday. On that day when I arrived at the observing site the sky was almost cloud less. But as soon as I completed setting up my telescope cloud began to cover the sky.

The cloud started to cover the southern sky, and gradually spread to the east. I sometimes could recognize the last quarter moon through the cloud, and the small portion of the western and the northern skies were starry. I decided to seep the Big Dipper, but the FOV looked bright and unpleasant. I applied a light pollution filter,
IDAS LPS-P2, which made it easy to observe nebulous objects under the moonlight.

I identified M97 and M108, and after a short time NGC3998 came into the FOV. There are many galaxies in the region but could not observe because of the clouds and the moonlight. After a while Polaris was covered by the cloud and the gap of the cloud opened only a part of NNW. I was forced to search Cassiopeia and Lacerta area. The Autumn Milky Way was beautiful thorough my comet-seeker even in the moonlight and the asterism of ET cluster NGC457 was impressive. I wondered what 45P/Honda–Mrkos–Pajdušáková was look like at that time. Unfortunately, I could not observe this comet by the daybreak.

Sunday, October 2

At 2:50a.m. when I had completed setting up my comet-seeker, almost all the sky was covered with cloud. I waited till 3:10, and finally, the clouds in the west and the north disappeared. I decided to search the northern sky.

The transparency of the sky was pretty good, but sometimes clouds interrupted my comet hunting session. I identified only four comet-like objects, NGC2268 (12th mag. in Camelopardalis), 2276 (11th, Cepheus), 2300 (1th, Cepheus) and 6503 (1th, Draco), which are located at the R.D. of higher than +70 degrees. I presumed this was the first time I observed those galaxies. I swept the sky hoping that a new comet appeared at the northern sky, unexpectedly.

NGC2276 (center ) and NGC2300 (lower left). The image is 15f wide.
The Digitized Sky Survey copyright©1994
I took a small break during the session, and observed C/2010 G Hill. The comet was 11th magnitude and defused but I had a feeling that it could be discoverable enough as long as not located at a low altitude.

On Thursday September 29, at the end of the comet hunting session, 45P Honda-Mrkos-Pajdusakova came into the FOV. It was 7th magnitude with a 10f tail and the turquoise coma was beautiful. This comet was more impressive than C/2009 Garradd that can be observable at the dusk probably because of a periodic comet and named Honda. This predawn the sky condition was better than that on Thursday and I wanted to observed 45P again. However, the constellation of Leo had been in the cloud till the daybreak and 45P never appeared. I am expecting the next clear sky while this comet is bright.

Sunday, September 18

I have conducted comet hunting sessions twice this month, but I could not afford to update my web page due to busyness.

Every year in September, I pay attention to near the celestial equator at predawn because it is the best time of the year for searching the Kreutz Sungrazers like C/1965 S1, Ikeya-Seki.

On Wednesday September 7 I got up at 1:30a.m. and on Friday September 9 at 2a.m., respectively, and drove to the observing site. Both at the two predawns more than half of the sky had been covered with cloud and I was forced to search limited areas of the sky.

On Wednesday I began with M42 and enjoyed many open clusters in Monoceros. NGC2264, Christmas tree nebula, was the most impressive object I identified during this session. I observed C/2010 G2 Hill for the first time during the session but it looked faint due to thin cloud. I felt it somewhat difficult to notice this comet image during the hunting session. After observing C/2010 G2 I resumed the comet hunting session in a minute but I had been annoyed by the clouds.

On Friday September 9 I started from Betelgeuse. I identified Hubblefs variable nebula that I could not observe on Wednesday. I was amazed the comet like shape at a glance. Again I cared about the Sungrazers, but in half an hour the eastern sky was covered with cloud. I aimed my telescope at the northeast and came across many 11th magnitude galaxies in Lynx and Ursa Major. When I finished the session over 80% of the sky was hidden by clouds.

Sunday, August 28

Bad weather has prevailed throughout July-August and I could not comet search at all.

We were stricken by earthquakes twice in October 2004 and March 2011, heavy snow in 2006 and flood July 2011. I am afraid I must say Tohkamchi is one of the most natural-disaster-damaged cities in Japan.

Beside natural disaster, our city is contaminated by radioactive materials released from Fukushima Daiichi. Niigata Prefectural Government announced that high concentration of radioactive cesium was found in the mud at the site of the swimming pool in a daycare center in my city last week. It contains Cs (cesium) 134 and Cs 137 and the total amount was 27,000 Bq/kg. Yesterday, the local government stated that the mud with Cs deposited at the bottom of the swimming pool was removed to clean in July and it was collected at the pool site: as a result radioactive Cs was concentrated 310 times from the original level in the soil that was 76 Bq/kg (6,700 Bq/m2).,0.pdf

This level of contamination, i.e. 76 Bq/kg, is not serious but not safe. I wondered if my observing sites were safe and measured radiation. I went to three major sites and confirmed the radiation dose rates. The dosimeter displayed 0.08 micro Sv/hour or less that is the same as natural value.

The situation at Fukushima Daiichi is still very serious, but little information is released by the Japanese Government and the media. I am afraid quite a few people still live in highly contaminated areas, and I must say the government is inhumane. I hope it ends soon, though it would take one century or so.

Sunday, August 8

It has been cloudy throughout this summer, and I could not comet hunt at all last month.

At the end of July we had heavy rain in Niigata and Fukushima Prefecture including my city, which wreaked enormous damage. No one expected that our city would be damaged by flood caused heavy rain, since the gentle slope of the city area drains rainwater into the Shinano-gawa river, the longest river in Japan, effectively.

However, the situation was abnormal this time and flood caused by small rivers with mudflow attacked houses, roads and railways. One died and one is missing. The rainfall intensity in Tohkamachi was record high of Niigata area: 121mm/hour in the evening of July 28. The total rainfall from July 27 to 30 reached about 500mm.
At the meteorological station of my workplace the highest hourly rainfall on July 28 was 98.5mm/hour (the highest record since 1917) and total rainfall was 464.5mm.

Floodwood with mudflow: about 300m from my office.
I usually commute by car crossing this red bridge.

A bridge of the railway was lost by a swollen river.

I hope rapid recovery from the damage.

Thursday, June 30

Clear sky!
I set the alarm clock for 0:50a.m. last night, but I did not expect starry predawn very much. I could manage to get up to notice the alarm ringing and change my cloths as soon as I had a look at the sky.

At 1:25a.m. the first thing I did after setting up my comet-seeker was to observe C/2009 P1 Garradd. Bright! I watched this comet for the first time. From just that position I stared comet searching.

In a minute an elongated galaxy came into the FOV. It was NGC7606 in Aquarius. I went to on sweeping and as my telescope having reached the horizon, I have reset it at an altitude of some 40 degrees and I made a second swing toward the horizon. The next moment, the second galaxy had passed the field: NGC7600. During my third swing the third galaxy, NGC7723, and the fourth swing the fourth galaxy NGC7727 had come into the FOV! Some of them were dark but I could identify due to good sky condition.

NGC7606@The image is 15f wide.
The Digitized Sky Survey copyright©1994

However, at 2:10a.m. mass of clouds hid stars, and I was forced search the northeast. At 2:30a.m. The clouds covered the eastern half of the sky, and again I needed to aimed at my telescope to the other direction, the south. This might be good for me as I enjoyed the summer Milky Way. M11, M17, and M20, these major showpieces crossed the FOV one after another during one swing! How impressive the gorgeous star clouds with meandering dark nebulae!

When I finished todayfs session, the entire sky was covered by the clouds. Thank goodness.

Sunday, June 12

About one month has passed since I comet hunted last, on May 15. The sky had been cloudy, hazy (caused by yellow sand from China), and humid, every time I went out of my bed in the wee hours or I drove to my observing site.

For instance, I got up at 0:50a.m. on May 25 and had a look at the sky. Then, 70% of the entire sky was covered with cloud, but I dared to go comet searching. Just when I had completed setting up my comet-seeker at the site, the sky had been overcast! I could observe nothing, but I took down my telescope and headed for my home.

The situation at this predawn was very similar to that on May 25. I left for my observing site where I discovered P/2010 V1 Ikeya-Murakami, and started comet hunting at 1:30a.m. At 1:45, only 15 minutes later, it got cloudy and I was forced to finish the hunting session.

Satellite images. A circle indicates the location of my city Tohkamachi. Left: 1:00a.m. June 12, 2011. Right: 2:00a.m. June 12, 2011.

Actually, I got a bad feeling before I left my home today since the meteorological satellite image that I checked prior to leaving home suggested deterioration in weather. The mass of cloud was moving toward my city.

Now that power saving is prevail nationwide due to damage of power stations by the quake and tsunami, the sky is obviously darker than pre-disaster period. I wait for dark clear sky patiently.

Sunday, May 15

The weather has been unstable this month and even if it was sunny yellow sand from China made the sky dusty and I could comet hunt only once. I had been waited for a clear sky, and finally the chance has come at this predawn.

Waxing moon set at 2:30a.m., but I started comet hunting before the moonset at 2:05a.m.: the twilight began at 2:55a.m. and I wanted to have enough searching time. M15 was the starting point of the todayfs session. NGC7177 was the first galaxy I identified during this session but it looked featureless object.

The second one was NGC7619 with another one only 7f apart from this galaxy. Both of them were 11th magnitude but I had to spend several minutes to identify the one near NGC7619. Here is a group of galaxies that consists of over a dozen of them (see the map below). I confirmed NGC7619 easily using the NGC Sky Vector, but there appeared some candidates when it came to identifying the galaxy near NGC7619. I opened a map, Uranometria 2000, and confirmed that the galaxy was NGC7626.

A galaxy group that contains NGC7619 and 7626. A circle indicates FOV of 1.3 degrees. MegaStar ver. 5.

The third one was NGC7479, a barred galaxy. I noticed the bar with a hint of the spiral structure! All the objects I identified belong to the constellation of Pegasus. When I was taking down my comet-seeker, Jupiter and Venus, the angular distance of them was 3.3 degrees, rose from the horizon. A beautiful daybreak!

NGC7479. This image is 10f wide.
The Digitized Sky Survey copyright©1994

Saturday, April 30

I got up at 1:30a.m. this predawn but the cloud covered the entire sky.
I have not been able to comet search for two weeks due to moonlight and cloudy weather, though I swept the sky six times in total this month.

The 41st Comet Conference

I have announced we will hold the 41st Comet Conference (CC) in Niigata city on July 16 to 17, 2011 (refer to the diary on  January 27), but the venue has been changed. One reason is that the Asteroids, Comets, Meteors meeting 2011 (ACM),which would have been held in Niigata, is postponed because of the disaster. Another is the rolling blackout that is planned in this summer in Niigata and some other area of Japan. Many electric power plants were damaged by the quake and tsunami that leads to lack of electricity.

New venue

The new venue is the Nobeyama, National Astronomical Observatory of Japan (NAOJ) where no blackout is planned.
The date and the program are the same with the original plan: Dr. Daniel E.W. Green, Director of CBAT and I will give presentations.

If you are interested in the CC please contact me.

Wednesday, April 6

Wonderful sky! Many power plants had been damaged by the big earthquake and tsunami, and we have to save electricity.

Usually the ski fields around my city open from early in the morning at this time of year with lighting at predawn. Some shops open 24 hours with bright illumination. However, after the quake most lights have been turned off and the sky became very dark.

I realize that the Milky Way was much brighter than usual even at a low altitude, and noticed the dark nebulae were easy to observe through my 46 cm comet-seeker. The stars shining in the Milky Way in Cygnus looked like grains of golden sand scattered on velvet. Today the transparency was not excellent but I reassured darkness of the sky is more important than the clearness for star watching.

I swept Cygnus and Pegasus, and identified only three DSOs: NGC6992 (veil nebula), 7217 (galaxy) and 7331 (galaxy). C/2011 C McNaught was bright with 9th magnitude, and this is the first observation for me. To date I have enjoyed comet hunting three times this month.

Sunday, March 13

On Friday, a giant earthquake with M9.0 struck northeastern Japan, and it is estimated more than 10,000 people died. The government still does not know how many people died or are missing. In Tohkamachi I felt a shock that had a long-period oscillation, but not very strong.

Surprisingly, another earthquake struck Tohkamachi at predawn on Saturday. The epicenter of this earthquake was only about 20 km from my residence with M6.8. The shock was very strong: some glasses and china bowls fell down from the shelf and were broken. Seismologists said this earthquake was completely different from the giant earthquake. It is unknown if the two earthquakes are linked or not, but I guess they are.

I conducted a comet hunting session this predawn, and mainly swept in the constellation of Sagittarius. I imagined the vastness of the universe from the countless numbers of stars I could see in the FOV.

Our planet is trivial in the universe, and only a slight movement of the small part of the plate triggers such a giant earthquake. However, thanks to this crust motion the Islands of Japan was formed where we live. All we can do is to accept the extraordinary natural phenomenon and appreciate that we are alive.

Friday, February 25

I have searched the predawn sky two days in a row, and this was the eighth hunting session this month!

 Yesterday, I overlooked NGC 6712, an eighth magnitude globular cluster in Scutum, because of the moonlight. Though the globular cluster was at an altitude of only 16 degrees when it passed through the FOV of my comet-seeker at 4:15a.m., I wonder if I made sense to do comet hunting under such a bright sky condition. I trained my telescope on NGC6712 at 4:20a.m. using the digital setting circles, but I could not see it at a glance: the image of this object was too faint to notice. I peered into the FOV for a several second and I could manage to recognize this "bright" object.

NGC 6712. Field: 15 arc minutes.
The Digitized Sky Survey copyright©1994

On the contrary, NGC6712 was obvious in the FOV today. The sky became much darker than that of yesterday due to waning of moon.

I started comet hunting at 3:55a.m. today and yesterday also. Yesterday, there appeared no cloud throughout the session, but today the amount of cloud increased as time went. Before 5a.m., the time when the twilight began, some 50% of the sky was covered with cloud, and this situation lasted till the end of the todayfs session at 5:30a.m. I searched where the gap of the cloud opened, but the DSOs identified during this session were no more than NGC6934 and M56. However, I was indeed satisfied with the beauty of the starry sky!

Saturday, February 5

It is incredible that I could comet hunt for consecutive days after over one month of snowy weather, though not all the sessions were good condition.

The sky was crystal clear since December 19 last year! I started comet searching from a few degrees west of alpha Liberae. The first deep sky object (DSO) I came across was NGC5824, a globular cluster in Lupus with a large apparent diameter of 7f. The second one was NGC5634, a globular cluster in Virgo that looked bluish with 78x, though individual stars were not resolved. The third object was NGC5903, a 12th magnitude galaxy in Libra, and I noticed a companion galaxy NGC5898 in the same field of view (FOV).

Beta Scorpii, a double star, was jaw-dropping. The primary looked pure white and I saw the secondary as yellowish, generally called blue, probably because of the low altitude.
M4 in Scorpius was impressive, and I was completely satisfied with the session.

The transparency was as good as that in yesterday. I began to comet hunt at Beta Scorpii and identified some 20 DSO during the session. Most of them were globular clusters, and among the most interesting objects were NGC6440 (globular cluster) and 6445 (planetary nebula). Both could be seen in the same FOV and located about 1 degree north-west of Venus.

@ @
M23, Venus, NGC6445 and NGC6440. A circle indicates the field of view for 1.1 degrees.
MegaStar ver.5.
@NGC6445, a planetary nebula (upper), and NGC6440, a galaxy in Libra.
The image is 30f wide.
The Digitized Sky Survey copyright©1994

Obviously, the transparency got worse in comparison with the previous day. I searched mainly in the constellation of Ophiuchus, but as time went the amount of cloud increased and I was forced to change the search area due to cloud. I trained my comet-seeker to the south. I identified NGC5878, a 12th galaxy in Libra, which I could not see in Wednesday because the altitude of this object was low at that time.

The sky looked hazy and I hesitated to go comet hunting. As a result, I decided to go but when I set up my comet-seeker the cloud began to cover the sky. I comet hunted for only 40 minutes till the sky got cloudy.

Thursday, January 27

It has been snowing for a few weeks and the snow depth has reached more than 260 cm. People in my city guess it will be more than 3 m this winter. There has been no chance to comet hunt this month here in Tohkamachi.

There are many restaurants and shops along this road. While I was driving, it was difficult to find the entrance of the shops due to snow wall.

Announcement of the 41th Comet Conference in Niigata City

The 41st Comet Conference (CC) will be held in Niigata City on Saturday July 16 and Sunday July 17, and I chair the conference again: I did last in 2007.

This time CC is linked with the Asteroids, Comets, Meteors meeting 2011 (ACM), July 17 to 22. ACM is an international meeting for professional astronomers. The venue of those two meetings are the same; Niigata Convention Center, Toki Messe.

The guest speaker of this yearfs CC is Dr. Daniel E.W. Green, Director of CBAT. I also give a speech on the comet discovery as I was requested to do. Dr. Greenfs lecture is translated into Japanese, and I will give presentation both in English and Japanese. Other presentations are also conducted with translation or bilingual explanations.

If you have a trouble with the language, members of the Scientific Organizing Committee of CC will help you.

The Local Organizing Committee will have the first meeting next month. Most members belong to the Niigata Astronomy Research Club (I do not know if this is an official English name) or Niigata Tenmon Kenkyu Kai in Japanese.

I am going to launch the web page in the near future.

Sunday, January 9

It has been three weeks since I comet hunted last here in Tohkamachi. While these three weeks, I had a comet hunting session in Nagano Prefecture in my way to my motherfs house at the end of December. Winter weather at the central or southern part of Nagano is generally fine in winter like at Ikeyafs place, Shizuoka.


Weekly forecast at Ikeyafs site (Shizuoka)  Copyright Japan Meteorological Agency


Weekly forecast in my city (Niigata)  Copyright Japan Meteorological Agency

Some people say that it was incredible that I discovered two comets in the area of bad weather condition. I see that this means I have always paid attention to the sky conditions in combine with the forecasts not to miss clear sky out. When I have a chance to conduct a hunting session, I concentrate on sweeping the sky.

The starry sky looks more beautiful after the long-term cloudy, rainy and/or snowy sky. The chance of clear sky must be less than one third of that of Ikeyafs site on an annual basis, and probably a tithe in winter.

I do not know when the next searching session can be conducted, but the passion for beautiful starry night is the motivating force for comet hunting that I want to keep.

I wake up at 2a.m. this predawn with a little hope for clear sky, but it was cloudy. I had a look at the sky again at 3a.m. again, but the sky condition was the same. OK, I will try the next time.

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