From my recent diary

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Monday, December 30

It has been nasty weather for three weeks; though I got up many times at the wee hours expecting the clear sky, I have not comet hunted since Monday, December 9. The sky had been clear during the daytime yesterday and today, but it changed to cloudy after the sunset.

The photo was taken on Monday, Dec. 30.

I went up Sakato-Yama Mountain 633 m above sea level, 37
˚03f32hN, 138˚53f55hE, on Saturday. I saw a lovely scene of a stone figure of the Buddha in the snow. A soft light casted a shadow of the statue on the snow. The comfortable weather turned into a snowstorm in 30 minutes, but I could reach the top of the mountain.

A stone figure of the Buddha partly buried in the snow.

The figure will be completely buried by the snow cover soon and we greet the New Year.

Thursday, December 5

I wake up a few minutes before the alarm clock rung at 2:55a.m. The sky was perfectly clear! I conducted a comet hunting session last Friday, and this was the first comet searching session since then. I got up at 3a.m. last Sunday and Monday expecting clear sky, but it was cloudy.

As the winter solstice approaches the time when I go on a comet hunting became late. While I was heading for the site by my car at around 3:30a.m. I saw newsman on the street. In early October for example, I drove before 3a.m. and usually I see no men on the street.

At the observing site I observed C/2013 R1 Lovejoy at first. With my 46 cm comet-seeker it has a tail over 2 degrees in length. It was an ion tail and there existed a dark band in the tail that divided the tail into two parts. The comet was seen by naked eye but I could not see the tail since the altitude of the comet was only 20 degrees when I observed it at 4a.m. The tail 0.5degrees long was easily seen by naked eye on Wednesday, Nov. 27 and Friday, Nov. 29.

At 4:10a.m. I began to comet hunting from Alpha Corvi. The DSOs I identified were NGC3887, 3981, 4038-39, 3892, M68 and NGC4361. Those were galaxies with 10th or 11th magnitudes except for the last two. I was a bit startled to see M68, a globular cluster in Corvus, as it looked like a comet but at the next moment I noticed what the object was; it was resolved into stars and I realized this old friend. At a glance NGC4361 also resembled a comet with high degree of concentration and I was taken aback but I remembered this planetary nebula in a second.

Speaking of NGC4038-39 (antennae-galaxies), I remembered I sketched these galaxies in 2002 about two months before the discovery of C/2002 E2 Snyder-Murakami.

I was enjoying the comet hunting session but gradually, the amount of cloud increased. Finally, the entire sky was covered with cloud at 4:53a.m. about 20 minutes before the start of the twilight. I wanted to observe C/2013 R1 again at higher altitude at 5a.m. A bit disappointing.

Sunday, November 17

Comet observation

In addition to C/2012 X1 LINEAR, C/2012 S1 ISON, C/2013 R Lovejoy and C/2013 V3 Nevski got bright this month probably influenced by activation of the sun as some people said.

I did not conduct comet hunting session because of moonlight, but observed those comets at this predawn.

C/2013 R Lovejoy

Bright with a tail and looked blue-green colored. The degree of concentration (DC) was
6 3 (corrected on Nov. 18, 2013).

C/2013 V3 Nevski
As DC was 0, it was very difficult to see under the moonlight. The comet was easily noticeable with the comet filter.

C/2012 S1 ISON
I have never seen a blue colored comet like this! With high DC (=
3 7) the color was light blue (corrected on Nov. 18, 2013).

C/2012 X1 LINEAR
I could not see this comet without the comet filter. Using the filter, this comet looked diffused and DC=0.

I tried to observe 2P Encke, but I could not due to haze near the horizon.

Saturday, November 9

I got out of bed at 2a.m. and the sky was very clear. Leo rose above the eastern horizon magnificently. But I drove to the site with some worry; the forecast said it might be cloudy at predawn.

Three minutes before I reached the site I noticed the sky got cloudy. I parked my car and confirmed that 90% of the sky was covered with cloud. I canceled the session and drove back to my house.

At the parking of my residence, unbelievably, I found the sky cloudless. I doubted if it must be a fake clear sky and waited for 5 minutes. However, it remained fine. Again I drove to the nearest site and started to set up my comet-seeker. Oh my god! It got cloudy again in 10 minutes when I was setting up the scope. I wondered if I could enjoy clear sky this month again as I live in one of the cloudiest areas in Japan.

Wednesday, November 6

I woke up at 1:30a.m. JST and the sky was crystal clear, but it was too early to go on a comet hunting. I stayed in my bed until 2a.m. and crept out of the bed.

At the observing site I enjoyed Hose Head nebula that was easily seen without a filter, C/20013 R1 Lovejoy and C/2012 S1 ISON. After 10 minutes of star gazing, I began the hunting session from M47 as the Winter Milky Way was attractive. The first DSO I identified was Sh2-311, an emission nebula adjacent to an open cluster NGC2467 in the constellation of Puppis. NGC2438, a planetary nebula in M 46, was obvious. NGC2588 a faint open cluster looked nebula like image at a glance but it resolved into several 13th to 14th magnitude stars if you peered at the object.

The emission nebula, Sh2-311 adjacent to the open cluster NGC2467. The image is 30 arc min. wide.
The Digitized Sky Survey copyright©1994

The faint open cluster NGC2588. The image is 15 arc minutes wide.
The Digitized Sky Survey copyright©1994

After I identified some 11th and 12th galaxies, at 3:40a.m., suddenly, seeing and transparency turned bad at the same time. I must looked over many small galaxies because it was challenging to distinguish small galaxies from stars that swelled due to poor scintillation, especially at a low altitude.

At 4:46a.m. I observed C/2012 X1 LINEAR and 2P Encke and I completed 2 hours of long hunting session at 5:10a.m.

Saturday, November 2

Comet hunting session with a journalist

Clear sky! This week I got up five times at predawn including today, and finally, I encountered the cloudless sky. I comet hunted last on October
11 15 (corrected on Nov. 4, 2013) , and since then I could not search due to moonlight and cloudy weather. There were some fine days during the daytime but not at predawn.

This situation is very similar to the discovery story of P/2010 V1 Ikeya-Murakami in 2010. At that time I conducted the comet hunting session on October 19 (Japan Standard Time, JST) before the day of discovery. The day of discovery was November 4 (JST) and the day after tomorrow is the third anniversary.

Today, I got up at 1:45a.m. and drove to the site with a reporter of The Asahi (a major newspaper in Japan) who was waiting for me at 2a.m. at the entrance of my residence. He is a science reporter and writes an article on comet searching this month. He has already interviewed me on the comet searching last month, and today was the on-site interview. We arrived at the site at 2:25a.m. and enjoyed stargazing prior to the hunting session. C/2013 R1 Lovejoy was bright with a tail, while C/2012 S1 ISON at a low altitude (about 10 degrees above the horizon) was so faint that the reporter could not recognize it even using my 46 cm comet-seeker. We also enjoyed some DSOs: M31, M42, M45, and h-kai (double cluster in Perseus). He said he was deeply impressed by an awful sky that he experienced for the first time. I believe his awesome experience makes an attractive article. The article will appear The Asahi on November 18.

I started the searching session at 3:25a.m. from some 5 degrees southwest of Regulus, alpha Leonid, as I did three years ago upon the discovery of P/2010 V1. Since the transparency on November 4, 2010 was much higher than that of this predawn I identified some 12th magnitude galaxies, but today I noticed none of the 12th magnitude one. Some 5 minute past 4a.m. C/2012 S1 came into the FOV during the hunting session. I told the reporter to try to see the comet again and he could observe the comet easily this time. At 4:30a.m. we observed 2P Encke and C/2012 X LINEAR. 2P got much brighter than in October. I observed C/2012 X1 for the first time, and I had an impression that this comet image is similar to that of P/2010 V1. The reason is, as some scientists pointed out, both C/2012 X1 and P/2010 V1 brightened due to the outburst. Photographic images of C/2012 X1 resembles 17P Holmes also. 17P is famous because it outburst and reached 2nd magnitude in 2007. The fifth comet I observed was C/2013 N4 Borisov but I only recognized the existence of this object, i.e. I could recognize the nucleus of this comet.

Photo and sketch images


P/2010 V1 Ikeya-Murakami

17P Holmes

I think this is the first time that I observed as many as four bright comets (brighter than 9th magnitude) at once. What a wonderful night with the reporter!

Monday, October 7

Superb sky! When I arrived at the observing site, it was easy to spot the Gegenschein (the counter glow) in the constellation of Pisces. It looked like an edge on galaxy, a round center with a pair of wings along the ecliptic plane.

The Gegenschein looked like an edge on galaxy as shown on this photo.

The star image in the FOV was pinpoint with Paracorr (ocular: Planokular 30 mm, D=457 mm/f=2037 mm), it means 78x with the FOV of 1.1 degrees. Prior to the comet hunting session, I observed three comets; 2P Enke was bright and defused with a short tail, C/2012 S1 ISON was still dark and C/2013 R1 Lovejoy was bright also had a short tail.

A galaxy group in Hydra.
The Digitized Sky Survey copyright©1994

I started the session from the north of Procyon, apopha Canis Monoris. The first galaxy I identified was NGC2555 in Hydra, the second was NGC2538 in Canis Minor, both were12th magnitude. As the transparency was excellent, unexpectedly, I identified those faint galaxies.

The third was a galaxy group, NGC2708, 2695, 2698 and 2699. The photo above contains NGC2697 that was too dark to be seen. I thought this was the first time I identified this group, but when I opened a map, Uranometria 2000, to identify NGC number of each one I found the underlines for those objects; I have ever observed the group. I saw many meteors in the FOV during the session and suddenly, a flash light penetrated the darkness. It must be released from a fire ball that I could not see.

It was a wonderful predawn.

Wednesday, September 18

Moonset was at 3:40a.m. and the twilight started at 4a.m. I enjoyed only 20 minutes of dark sky. I started the hunting session at 3:25a.m. from M42 in the same way as that on September 4 when I missed C/2013 R1. This time I used 78x magnification combining Planokular 30 mm eyepiece with Paracorr 2. The star image is pinpoint and the FOV becomes flat with Paracorr. But I stopped using Paracorr after the discovery of P/2010 V1 Ikeya-Murakami since the actual FOV reduces from 1.3 degrees to 1.1 degrees by applying Paracorr. Using Paracorr or not? Both are correct.

The objects identified were the reflection nebula in NGC2232 and C/2013 R1. I was satisfied with beautiful stars in the flat field and completed the session at 4:35a.m.

I will appear on TV program next Sunday (on air in domestic only). The title of the program is Galileo X, and this is the 61st story: gThe great Comet, ISON is coming: a fossil of the Solar system that records the state of the Universe of 4.6 billion years agoh.

I got interviewed on comet hunting.
Web pages of the TV program.

Major casts:
Junichi Watanabe (NAOJ), Shigeki Murakami (amateur), Seiichi Yoshida (amateur), Yoichiro Nakashima (amateur), Hideyo Kawakita (Kyoto Sangyo Univ.), and Reiko Furusho (NAOJ)

It was somewhat hard to get interviewed, because the coverage involved both indoor interview and outdoor one. At predawn a scene of a comet hunting session was shot. It had been cloudy and rainy those days, and I worried about raining. Fortunately, the day when the TV staff planned to shoot the comet hunting session was cloudy with some cloud gaps. I hope many people will have interested in comets by watching this program and Comet ISON gets the great comet.

Tuesday, September 17

A typhoon has passed and the weather forecast predicted the clear sky. At 2:20a.m I finished setting up my comet-seeker at the observing site. Prior to the searching session, I trained my telescope at C/2013 R1 Lovejoy that was at an altitude of 20 degrees. With 68x magnification the comet was not seen, but I noticed it with 78x. In my impression the possibility of discovering this comet with 78x was 40% to 50%. With 92x magnification the chance of discovery was 70% to 80%.

After observing Comet Lovejoy I began the hunting session, but suddenly, the amount of clouds increased and I had to wait until 2:50a.m. to resume the session. The motion of clouds was rapid and sometimes the entire sky was covered by clouds. The only comet-like object identified was NGC1788, a reflection nebula.

At 4:00a.m.the time when the twilight began I observed C/2013 R1 again. The comet was at an altitude of 37 degrees and seen 68x magnification with the chance of discovering of 10% to 20%. I also observed C/2012 S1 ISON but the magnitude was 13th by intuition. I tried to see C/2013 N4 Borisov and I could spot extremely faint image of this comet for the first time.

Wednesday, September 11

The discovery of C/2013 R1 Lovejoy has been officially announced. I observed this comet today with a magnification of 157 using my 46 cm comet-seeker. However, the comet was not seen with 68x in the same way with C/2012 S1 ISON that I observed last Wednesday.

C/2013 R1 Lovejoy
September 10.715, 2013 UT
Magnitude: 12.7, apparent diameter: 2.6f, the degree of concentration (DC): 2.

As I mentioned in the previous daily, I swept the sky area where C/2013 R1 was on today last week (September 4) before the discovery. Today I confirmed the position of the comet and found that I missed discovering this comet by a hairsbreadth! I identified NGC2110 at around 2:40a.m. on Sep. 4 (JST) and amazingly, the comet was in the same FOV with NGC2110 at that time. The comet was not seen with 68x, the usual magnification I use, but was easily noticeable with 157x at this predawn. If only I changed the eyepiece to Ethos 13 mm (157x) to confirm the suspicious object, NGC2110, I could have discovered the comet, as the distance between the comet and the galaxy was only 25f.

C/2013 R1 and NGC2110 in the same FOV. The circle represents 1.3 degrees for 68x. September 3.736, 2013 UT (before discovery).

After observing C/2013 R1, I comet hunted the River Eridanus. I identified two galaxies, NGC1417 and 1600. When M79, a globular cluster in Lepus, came into the FOV at 3:15a.m. the sky began to be covered by clouds. In 10 minutes the sky was overcast.

Wednesday, September 4

I had been waiting for the clear sky, and finally I could comet hunt on Wednesday. Later at home I looked at the weather chart and I was surprised; the front was over my city at the time of the comet hunting session but the sky was clear. However, star images in the FOV of my comet seeker were very unstable. Seeing was extremely poor at the beginning of the searching session and in several minutes later it recovered to moderate condition. In 10 minutes it became bad again. Such a pattern was repeated many times during the session.

The weather chart and the satellite image at 6a.m. on Sep. 4, 2013.
The red dots indicate the location of my city.

NGC2110. This is a Seyfert galaxy.
The image is 30f wide.
The Digitized Sky Survey copyright©1994

I aimed my comet-seeker at M42, the great Orion nebula and started the session from there. Some 5 minutes after the beginning of the session, I encountered a double-star-like object. I peered at the object and I tried to believe it as a double star, but I could not since the image was stable; if it was a double star the starsf image must deform with time due to air turbulences but it did not. I checked the object using the digital setting circles and it turned out to be NGC2110, a 12th magnitude galaxy in the constellation of Orion. The apparent diameter was around 1.5f and it was difficult to distinguish it from a double star because of bad seeing. Anyway, I was satisfied to identify this galaxy at an altitude of 18 degrees.
At this session I had a plan to observe C/2012 S1 ISON. I tried to observe it at 3:52a.m. The expected magnitude was 12 to 13, but it seemed to be challenging because of bright zodiacal light. I could see nothing at the position with the magnification of 68 but succeeded in identifying the comet with 157x. The altitude of the comet was 15 degrees. Later in the session I also identified NGC2170.

Surprising news!

While I was writing this manuscript, the Japanese comet mailing list announced that a new comet was discovered. The position was within the area where I covered on Wednesday! The official announcement has not made yet, but discoverer was Terry Lovejoy and it will be named C/2013 R1 Lovejoy. The comet was not bright enough to be detected with my comet-seeker.

Sunday, September 1

In August it has been unstable and nasty weather nationwide and I could not comet hunt at all due to the poor meteorological condition. Even if the sky was clear in daytime, it turned into cloudy during the night. I have paid attention to the forecast and I got up when the clear sky was expected; however I was always clouded out.

For example, the chances were clear sky at predawn on August 29 and I got up at 1:30a.m. and 2:00a.m. but it was in vain. Ironically, at 8a.m. the sky was cloudless but it changed into overcast at the night.

At 8a.m. the sky was cloudless on August 29.

Weekly forecast announced on September 1.

I remembered that there were less fine days in August, and I checked the record. I conducted comet searching sessions 2 nights in 2008, 3 nights in 2009, 6 nights in 2010, one night in 2011 and 8 nights in 2012. The variation was very large, but I think I have been able to comet hunted every August in the past.

I comet hunted last on July 9, and I could not since then. I wonder if I can on Thursday or Friday.

Friday, August 9

It has been cloudy and rainy since I comet hunted last on 9 July, though the meteorological agency announced the end of the rainy season on 3 August.

I made setting circles that I have had a plan to make for many years. I used silver colored spray paint for painting and draw graduation by a felt-tip pen. I have ever encountered a sudden dead of battery, while I was using the NGC Sky Vector during the comet hunting session. It is hard to deal with such a situation, especially when you spot a possible comet. Setting circles work out when it comes to such an accident.

Setting circles of azimuth and altitude

Altitude circle

Azimuth circle 1

Azimuth circle 2

If you can level the telescope at the time of setting, altitude circle indicates the correct value. You can level it within 0.5 degrees easily. But it is almost impossible to set the zero point of the azimuth scale to the north. Assuming that the azimuth scale indicates 13.0 degrees (shown in photo
"Azimuth circle 1"), and actual azimuth angle of Antares is 180.1 degrees. The azimuth angle indicator is made of thin stainless steel plate and is fixed on a sheet of magnet. The plate is easy to slide. If you move the indicator (the plate) to the azimuth angle of 10.1 degrees (shown in photo "Azimuth circle 2"
), the difference between actual azimuth and the scale is 170.0 degrees. You can see the azimuth angle by adding 170.0 to the indicated azimuth scale.

By combining the setting circles and iPod appri, the altitude and azimuth of DSO or the center of the screen is shown; you can identify DSOs when the NGC Sky Vector does not work.

Tuesday, July 9

I was happy to go on a comet hunting this week as I expected, though the rainy season (Baiu) has not yet finished officially. I went to the site where I visited on daytime two weeks ago, and this was the first time I set my comet-seeker on the site. It took some 25 minutes by car from my residence, 7 or 8 minutes farther than the usual site, but the longer drive paid off. The eastern sky is darker than at the usual site.

The left image is 20f wide and the right one (NGC779) is 15f.
The Digitized Sky Survey copyright©1994

I started with the hunting session at 1:30a.m. from Deneb Kaitos, beta, Ceti. The first DSO I observe was NGC132, a dark galaxy in Cetus. It was 12th magnitude and looked like a planetary nebula as the surface brightness was homogenous. NGC584, 596 and 615 group passed through the FOV and I noticed all of them easily. Another galaxy group, NGC467 and 474 in Pisces happed to come into the FOV at 3:05a.m. over 20 minutes after the start of the twilight. NGC470 (shown on the photo) was too dim to see with my 46 cm comet-seeker. In a few minutes very elongated galaxy, NGC779 (11th magnitude) in Cetus, was impressive, but it was not the last one. NGC488, a 10th magnitude galaxy, was bright enough to be seen clearly 30 minutes after the start of the twilight.
When I was taking down my telescope, cloud began to spread all over the sky.

Sunday, July 7

I had a plan to go on mountain climbing today, but it was canceled due to rainy weather. We have few clear skies at this time, now that it is rainy season.

Comet hunting activity has been similar situation. I have not been able to comet hunt since June 13 because of moonlight and nasty weather.

At predawn on June 13 the sky condition was excellent but the amount of cloud was more than 70% throughout the session. Soon after the start of the session, I encountered M33. Then, a galaxy group in Pisces that includes NGC507 and another faint one came into the FOV. The altitude of the galaxy group was some 20 degrees and the magnitudes of these galaxies are 11th and 12th, respectively. NGC507 was easy to identify using the digital setting circles. However, as I forgot to bring my iPod in which gDeep Sky browserh is installed, I could not identify the darker galaxy exactly using the digital setting circles: there are many galaxies in this area.

NGC507 (lower left) and NGC499 (upper center).
The Digitized Sky Survey copyright©1994

I opened Uranometria 2000 but it took over 5 minutes to identify darker one, NGC499. It might be a strategy to believe darker one must be a member of the group skipping the check using a map and to go ahead. But I did not want to do so at that time.

At the latter half of the session, cloud covered the eastern sky, and I trained my comet-seeker at the north, the only cloudless direction. Suddenly, I came across a bright object. A new comet? Ruthlessly, the NGC Sky Vector identified it as NGC2655 (10th magnitude) in a second. I was not familiar with objects in the northern sky where I rarely search. I also noticed NGC2715 (magnitude of 11.4) in the same FOV.

I believe the rainy season (Baiu) will end this week and I can enjoy deep sky objects again.

Saturday, June 8

Light pollution

So far I could comet hunt three times in June. In addition to the hunting sessions I wanted to enjoy observing deep sky objects at dusk, and I went to an observing site on Monday June 3. My wife also wanted to do a star watching and we drove to one of the best sites where a 40-minutes-drive from our residence. We arrived at the site before the end of the twilight. To our disappointment, the sky did not get dark after the end of the twilight and it looked very bright mainly due to light originated from the baseball game grounds several kilometers away. The sky had been bright as if the twilight had been about to start.

Figure 1 Light source around the observing site. 



Figure 2 Light pollution in Japan.

The tail of C/2011 L4 PANSTARRS was not conspicuous because of the light pollution. We observed some Messier objects; the most impressive one was M13. We observed some other globular clusters but as they say, I completely agreed that M13 is the most beautiful globular cluster in the northern hemisphere. M57 was also very interesting, though I could not recognized the central star. I have often encountered these objects during the hunting sessions, but observing a certain object spending a lot of time and changing the eyepiece offer different kind of fun.

At 10a.m. the ballgames seemed to be over, and the sky was getting dark. Then, we saw we were the member of the awesome universe. At this time the degree of light pollution was the same with that of predawn. Figure 1 shows the light sources. The triangles around the site in the figure indicate the origin of the lights. The thicker the line of the triangle is, the worse. The strongest light source at the site is Tohkamachi, where we live. Tohkamachi is a small city, but there is nothing to intercept the light between Tohkamachi and the site, which makes it the strongest light source. The light from Yuzawa is cut by the mountain range. The second strongest is Nagano and Jyoetsu, and the third is Tokyo area including Gunma (Takasaki and Maebashi).

If you look at the entire Japan (Figure 2), Tohkamachi area is very nice place for star watching in terms of darkness of the sky, but even so, light pollution at dusk is serious enough to disappoint most people.

Wednesday, May 22, 2013

Wonderful sky of the last Saturday

Today was the last dark predawn before the full moon on Saturday
CMay 25. Although it was cloudless at predawn, I did not go on a comet-hunting due to yellow sand from Chinese dessert. It made the sky very hazy.

So far, I conducted seven comet hunting session this month, and the session of the last Saturday, on May 18, was the most enjoyable among them. This month I have been disappointed at hazy sky mainly caused by the yellow sand from China, but this time the sky was hazy free. In addition to that I went to the new observing site for the first time where I have looked beforehand last year. The site is 660 m above sea level and took 30 minutes from my residence, while the usual site is 370 m and 15 minutes. When I approached there at the end of April, the road was covered with snow and I could not reach the site.

When I arrived at the new site, all the stars looked glargerh in apparent diameter and they seemed to be cheerful. I could see the 6 th magnitude stars and M13 with my direct vision. I could see the faint part of the Milky Way in the constellation of Ophiuchus.Before the start of the session, I enjoyed some deep sky objects with 50mm x8 binocular and my 46 cm comet-seeker: M8, M13, M22, M51 and Veil nebula. Every object looked much brighter than usual and was impressive with any aperture! I must say it is worth visiting farther site.

The hunting session in itself was not special. I began with M72 at 1:50a.m., I have to get up very early at this time of the season, and only two DSOs were identified: M30 and M2. But the dark background made me comfortable. Before 3a.m. I trained my telescope at C/2011 L4 PANSTRRS. The ion tail stretched over one degree, and the angle between this tail and wider dust tail was some 165 degrees. C/2012 F6 Lemmon looked brighter than C/2011 L4, but the dust tail was short. I enjoyed a quick look at those comets and resumed the searching.

International Space Station passed through Pegasus.

At 3:18a.m. when I looked at the east by naked eye, International Space Station passed through the quadrangle of Pegasus. At the same time I noticed Fomalhaut rose above the horizon. I completed the session at 3:35a.m.

Friday, May 10

C/2012 F6 Lemmon and fire-ball on May 6

I conducted comet hunting sessions four times in May including todayfs one. Unfortunately, transparency of the sky was moderate or poor all the time as is always the case with this season. Among them the session on Monday May 6 was the most impressive.

I trained my comet-seeker at the south-southeastern sky, since the eastern sky was very hazy that intensified the light pollution while the south is the only light-pollution-free direction. I began with M22, a globular cluster in Sagittarius. I observed several meteors passed through the field of view (FOV) during the session; today was the maximum of the Eta Aquariids. The first deep sky object (DSO) that appeared in the FOV except for M22 was NGC6723 in Sagittarius that is located near the boundary of Corona Australis. The other DSOs identified this session were M54, NGC6712 and M75.

The crescent moon, beautiful as a goddess, rose from the hill. At 3:00a.m. I tried observing C/2012 F6 Lemmon for the first time, but I could not due to haze and too low altitude of the comet. I tried again at 3:35a.m. and I successfully observed this comet. I also noticed short tail of the comet.

I completed the session at 3:45a.m. and started to take down the telescope. Suddenly, at 4:00a.m. something emitted a flash of light. I thought it must be a fire-ball and looked up the sky quickly. I managed to observe the fire-ball before it disappeared and the meteor trail moved like a snake afterward.


It was national holiday today, and I went to a small mountain, Nabekura-yama, 1288 m above sea level (3658f35.6hN,
13822f56.4hE) on daytime. The mountain was the paradise of the skiers where the snow depth was some 2 m and there is a beautiful old Japanese beech forest. I recharged the battery with the hike.

Tuesday, April 23

C/2013 E2 Iwamoto and C/2011 L4 PANSTARRS

I started a comet hunting session at 2:58a.m. a few minutes before the moonset. Several minutes later after the moonset when I looked up the sky, the Milky Way was splendid with higher luminosity. The twilight began at 3:25a,m. and I could enjoy the dark sky only some 25 minutes. Lyrids was its peak this predawn. Luckily, I saw a 1st magnitude Lyrids meteor.

During the session I identified merely two deep sky objects: M2 and M15. The highlight of this predawn was observation of comets. Unexpectedly, C/2013 E2 Iwamoto was bright; magnitude: 11.3, diameter: 2.3f, DC: 2. At first I thought the cause of easy observation of this comet was due to excellent transparency, but I noticed the comet brightness actually increased when I measured the brightness.
Another comet I had been wanted to observe was C/2011 L4 PANSTARRS. I saw this comet last on April 5 when it was near M31. At that time the transparency was very poor and tails were not observed. This time not only the dust tail but also the iron tail was easy to observe. I did not make an observation for brightness. The angle between the two tails was 120 degrees and there existed gaseous material between the tails that formed fan-shaped tail as a whole. It looked more beautiful than photo images!

I finished the session at 4:00a.m.

Thursday, April 18

Urania observatory

I have been in Vienna, Austria, last week to attend a scientific conference as a forest hydrologist. While I was there I happened to find an astronomical observatory.

Urania observatory

The explanation shown on the wall of the building was written in German and I could not understand. Anyway, I entered the building and went up to the floor where the telescope dome is. The doors were locked and no one was there. When I decided to give up contacting a staff, I saw a man walking over the glass wall. I spoke to him and he said he could show me the telescope.

Telescopes Face plate in the dome

The telescopes were 15 cm and 10 cm refractors for solar observation with Cassegrain reflector. He showed me the sun using refractors. Seeing at that time was superb and there were many sunspots when I peered the 10 cm refractor using a solar filter. He installed a H alpha filter and Pentax XL 40 mm eyepiece on the 15 cm telescope. I have ever seen the H alpha solar image a few times, but this image was the best! I enjoyed spectacular image for several minutes.

He said the observatory was built in 1910, but was destroyed in the war. This building was rebuilt in 1956. The war is crazy.

Friday, 22 March

C/2013 E2 Iwamoto

This is the 5th comet hunting session in March. Though air temperature was -4 deg. Celsius, I felt it was much colder. I think this was because my body was accustomed to warm climate on daytime. I started with M16. Transparency at a low altitude was poor and I could not identify M55. NGC6539 and M75 that seemed to be a comet at low altitude were comet like objects I identified during the session. NGC6712 and M11 were spectacular including the star ground around these objects. I must say the field of view (FOV) was gorgeous with numerous stars that showed various colors and decoration by dark nebulae. These objects came into the FOV one after another. It was as if the FOV had been filled with open clusters all the time.

M11 and the star ground. The width of the image is 2 deg.

At 4:20a.m. one hour after the beginning of the session, I aimed my comet-seeker at C/2013 E2 Iwamoto. I could not recognize the comet with 68x, and increased the magnification up to 155x using Ethos 13 mm. Many stars looked like the comet since the star image was swelled due to bad seeing. At the position of the comet I barely saw dim image of the comet. It was 13th magnitude with a diameter of 0.5f. It was impossible to spot the comet during the session under such poor seeing and transparency. Anyway, I was happy and satisfied with observing the comet discovered by Japanese

Saturday, 16 March

C/2013 E2 Iawmoto, C/2011 L4 PANSTARRS and 273P Pons-Gambart

New comet C/2013 E2 Iawmoto was discovered by a Japanese! The discovery was made using digital camera. I think visual discovery of this comet must be difficult even with my 46 cm comet-seeker.
Actually, I swept near the position of the comet on Friday, 15 March. I began with the session from Altair, alpha Aquilae, at 3:25 a.m. (14.7674 UT), when the comet was only 3.5 deg. above the horizon and I think the discovery had not yet announced. The difference in azimuth between Altair and the comet was only 0.5 deg. that meant the comet was in the field of view of my comet-seeker if tree height near the horizon was lower than 3.5 deg. Even if the trees did not hide the comet, it was impossible to spot such a dark object with an altitude of only 3.5 deg.

I tried to observe this comet today, but I was clouded out at 4:10 .am. when the altitude of the comet was still low: 12deg. Photo magnitude was announced to be 13 to 14, but some visual observers reported it as 12th magnitude. However, visual discovery was challenging. The important thing is that this discovery demonstrated that we, amateurs, still have a chance of discovery.

Today, I observed 273P Pons-Gambart prior to the comet hunting session. I estimated the magnitude was 12.5 by intuition, which was difficult to spot during the hunting session even with the altitude of 70 deg if not impossible.

I observed C/2011 L4 PANSTARRS on Tuesday, 12 March for the first time using 20 cm reflector and 7x50 mm binocular. The comet was also observable with 6x30 mm finder, but not by naked eye since there is a hill with an altitude of 5 deg. at the site and the comet set over the hill before the sky getting dark enough. I also took a photo of this comet on Thursday, 14 March which well reproduced visual image of the binocular.

Click to enlarge
Data is here

This is the fourth comet hunting session in March. Yesterday, Friday 15, it was very cold with temperature of -9 deg. Celsius, while today it was -1 deg.
Ironically, the lower the air temperature gets, the more beautiful the star field looks. Nothing ventured, nothing gained.

The Chinese comet hunter Wentao Xu sent me a composite image of corona, the totality in Australia, and I replaced old one with this. In my impression this is one of the most real images I have ever seen which reproduced the visual image.

Sunday, 17 February

On Friday a meteorite fell down in Russia, Chelyabinsk Oblast, and the shock wave injured over 1,000 people with damages of many buildings and facilities. On Saturday Asteroid 2012 DA14 went through only 27,700 km above Earthfs surface; I could not observe it because of snowy weather. The orbits of those two asteroids were completely different but it is surprising Russian meteorite explosion occurred the day before the close pass of 2012 DA14.

This reminds me that in 2008 a few meters sized asteroid, 2008 TC3, was discovered and predicted to enter the earthfs atmosphere after 20 hours of the discovery. Surprisingly, after the collision, fragments of the meteorite were collected over the Nubian Desert of northern Sudan. The Russian meteorite was much larger than 2008 TC3, but the robotic survey was failed to spot it and cased unexpected damage. The survey could not detect the Russian asteroid because it came from the direction of the sun.

You must remember that the survey does not cover not only the direction of the sun but also the low altitude of the sky at dusk and predawn. I discovered a comet on February 26, 2004 that was not confirmed and was lost. I believe the comet was the near earth object that moved with a high speed and no one confirmed after my discovery. Minoru Honda and an anonymous Japanese comet hunter said they encountered comets with quick motion which they could not report due to high speed. I think there are still many near earth objects that the survey fails to detect. Chances are you can still discover new comets, which may even threat the earth.

I have read somewhere that the chance of the meteorite collision to the earth with a comparable size of the Tunguska explosion in 1908 would be one-in-100-year (
Yeomas et al. estimate 300 years). I felt the estimation was reliable to hear the news of Russian meteorite on Friday, but luckily the size of the meteorite was much smaller than that of Tunguska. If it has been the same as Tunguska, some 1,000 times (Yeomas et al. estimate 185 times) as strong as Hiroshima atomic bomb, the damage would have been devastating; on top of the harm of the explosion itself the nuclear facilities in the Chelyabinsk Oblast would be destroyed that could cause severe radioactive contamination like Chernobyl or Fukushima.
Yeomas et al.

Besides the impacts of asteroids and comets, we are threatening various natural disasters.
The other day, Richard Brown, the Australian comet hunter told me the Siding Spring Observatory had fire and was about to be burned down. As a result, it was safe but in Australia fire is a major risk that people encounter in their daily life. The fire runs with speed of 100 km/h and it is impossible to escape from the raid.

Similarly, in Japan earthquakes and tsunamis are serious threat that we sometimes cannot avoid.

We, human beings, have a potential to spot asteroids or comets that threat our planet and avoid the catastrophe using technology. However, in some cases the extinction of human kind caused by the impact of the objects is unavoidable. We are fortune to live and must feel grateful to our ancestors who have been developed our civilization for tens of thousands of years.

Utilization of nuclear energy, whether accidents like Chernobyl or Fukushima at the atomic power plants occurs or not and whether it is military purpose or not, damages DNA that can die out many kinds of species including us.
We never use science and technology for vice. Those who have power want to keep using nuclear energy because it is equivalent with nuclear weapons; they want to have nuclear weapons. I must say Fukushima Prefecture except for Aizu, the western part of the prefecture, will disappear in a several years. Tokyo area is not a safe place to live especially to raise children. We should not harm ourselves anymore and must stop using nuclear energy; even if this is not the case, we may be extinguished by the impact of asteroid or comet.

Friday, February, 1

I comet hunted for the first time this year. I arrived at the observing site at 3:25a.m. and started the hunting session at 3:55a.m. under the moonlight.

I trained my comet seeker at M12, a globular cluster in Ophiuchus, and began with the searching session from this globular cluster. Messier 12 was dim because of bad seeing and the moonlight. At the next moment M10, which looked brighter than M12, came into the FOV. As cloud covered a part of the sky for a while, the only Deep Sky Object I identified except for M10 and M12 was M14.

As time went by the number of stars in the FOV increased because the telescope moved into the Milky Way area. I remembered that when I discovered C/2002E2 Snyder-Murakami I began to the comet hunting session from Ophiuchus, the same constellation I started searching this predawn. This comet was discovered in the Milky Way.

I tried observing 273P Pons-Gambart for the first time at 4:35am. but I failed to do. Then, this comet must pass through the FOV at around 5a.m. but I did not notice. At about 10 minutes past 5a.m. I tried to see the comet again and I found a very faint object, however I was not sure if it was the comet. At 5:25a.m. I aimed my comet seeker at 273P again and confirmed the faint object was the comet! It was 10th magnitude and it was difficult to spot this comet during the hunting session under the moonlight. I was happy to observe the comet that returned 185 years after the discovery.

Thursday, January 24

I got up and looked up the sky at 3a.m. but it was overcast again. This predawn was the last chance to have a comet hunting session this month. The next predawn must be snowy and the waxing moon makes visual hunting difficult the day after tomorrow. I got out of bed at predawn three times in January, but as a result I had never comet hunted. OK, no need to worry. This is the norm here in this area.

Ironically, the sky was very clear for a few hours after the sunrise. The surface of the snow was frozen early in the morning, but it melted as the sun rose higher. The footprint of a rabbit on the snow was impressive.

Foot print of a rabbit on the snow.

On Saturday 12 the sky was clear and I went to comet hunting at predawn. It was very cold with a breeze and the air temperature was -9 degrees Celsius. I thought it was one of the chilliest predawns I have ever experienced while comet hunting. While I was setting up my comet-seeker, filmy cloud gradually appeared, and five minutes before I completed assembling the scope it got overcast. On the same day at dusk I set up the telescope again to observe C/2012 K5 LINEAR. This time the sky was perfectly clear. When I aimed my comet-seeker at the comet, thin cloud started to spread. The comet was faint then I expected due to the light pollution caused by the ski fields. Just when I changed the eyepiece for higher magnification, the comet disappeared; it got overcast again. I saw the comet only three minutes. Do not worry; it was much better than see nothing.

Sunday, January 6

Yesterday, it was very clear in the morning, but cloudy until sunrise. I wish the sky had been clear at predawn.

I went skiing in the morning and could see my usual observing site from the ski field. The ski field was 20 minutes from my house by car, and I looked down at the site in farm land from the upper part of the ski slope. The red dot on the photo shows the site where I discovered P/2010V1 Ikeya-Murakami and 255P Levy that was not my discovery officially.
The photo was taken at the ski field, gNakatato Kiyotsuh, 4 km south-southeast of the observing site: 13841f40hE, 3801f26hN, 375 m a.s.l..

The red dot shows the observing site where I discovered
P/2010V1 Ikeya-Murakami and 255P Levy.

Beech trees at the top of the ski area.

The forecast said it will be snowy or cloudy through this week, but I should pay attention to the weather. It may be off the mark unexpectedly.

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