From my recent diary

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Sunday, December 28

The sky was clear and I was satisfied with todayfs session. I comet hunted last on Wednesday, December 3, and more than three weeks have passed since then. Actually, I tried to conduct a searching session on Wednesday, December 24, but as soon as I had set up my comet-seeker thin clouds covered all the sky. I stayed the site until the daybreak but in vain and went backed home. Since then have I waited for clear sky and finally the time has come: todayfs session was special since I introduced new gadgets for the first time.

Introduction of new devices

This predawn I employed two new devices. I believe those make my comet hunting activities more enjoyable.
One was Nexus DSC (Digital Setting Circle), an Australian made high performance device (, and another was iPad mini 2. As for a DSC I have used Lumicon NGC Sky Vector and its Japanese version (Navigator, Kokudai Kohki ). The old DSCs function very well still now, but Nexus DSC features various kinds of functions including WiFi to smartphones and tablets. Upon upgrading to the new DSC there was no need to replace the old encoders installed on my comet-seeker, instead I merely changed a DSC from NGC Sky Vector (or Navigator) to Nexus DSC, though I fabricated an attachment to set Nexus DSC to the secondary cage of the telescope.
I installed a planetarium software, SkySafari 4 Pro, in iPad mini 2 that receive WiFi from Nexus DSC and the position of my come-seeker is indicated on the display. How exciting it is to check where the telescope is trained on the display!

Nexus DSC has internal rechargeable battery. The battery residual capacity reduced to 87% from full charge after two hours of operation under the air temperature of -7 ˚C. I think the battery has enough practical capacity. Three ways of recharge cables are available: AC, car cigar lighter and USB. Note AC adapters for international use.

I made an attachment so that Nexus DSC can be attached on to the telescope tube using Velcro (black colored). The white plate made of a 3 mm-thick PVC.

Todayfs session

I set Ethos 21 mm eyepiece on the drawtube (97x, FOV=1 degree) and I aimed my comet-seeker at M104 using SkySafri 4 Pro with Nexus DSC. I tapped M104 on the display (SkySafari) and then tapped eGoTof. Nexus DSC indicated the angular distances (horizontal and vertical) to M104 just like NGC Sky Vector does and I moved my comet-seeker so that the both values became to be zeros. The same thing can be done using Nexus DSC only, but it was easy and comfortable to use those devices in tandem. Through those processes, I started todayfs session from M104.

Having said that, I have wasted a certain amount of time during the session as I was not familiar with those devices; I overlooked many galaxies that would have been identified if I had been calm as usual. I often checked DSOs that came into the FOV by using the iPad mini, but I saw that it is not effective to look at the display (SkySafari) too often. I decided to use mainly Nexus DSC (identifying function) to identify comet-like objects as I have done as before, and I utilize iPad mini when multiple objects, i.e. galaxy group, come into the FOV. An example of such a galaxy group is shown as a screen shot of iPad mini (SkySafari) and an image of DSS.

I spotted 32 galaxies during the session and covered 40x30 square degrees (vertically and horizontally) during two hours. Todayfs weather was very severe: besides the 2 m of snow depth, air temperature was -7 ˚C with weak wind that made sensible temperature lower, but I was happy with the new devices.

DSS image of NGC5076 (magnitude of 13.1), 5077 (11.4), 5079 (12.0) and 5088 (12.6) that corresponds to the screenshot below. Note that the south is up and the field is 30f.
The Digitized Sky Survey copyright © 1994

Screen shot of SkySafari 4 Pro shown on iPad mini 2. The horizon is up and a circle is 1 degree in diameter that indicates the FOV of my comet-seeker with Ethos 21 mm eyepiece.

Wednesday, December 3

It is unusual that we have clear sky two consecutive days at predawn in December; I could comet hunt yesterday and today. I have purchased Ethos 21 mm eyepiece from a US dealer that makes a magnification of 100 with an actual FOV of 1.0 degree combining with my 46 comet-seeker, and I used it for the first time yesterday.

The difference of magnification between 78x (Planocular 30 mm 88 degrees + Paracorr) and 100x (Ethos 21 mm 100 degrees) is significant. The background in the FOV got darker due to higher magnification that makes searching activity effective, not to mention the super wide field. I felt it was very comfortable to use this eyepiece. As I wrote the other day, I could notice darker galaxies easily than using 78x. On top of that, it reveals detail structures of galaxy and I enjoyed looking at it. However, I could search only 15 degrees per hour horizontally (with 40 degrees vertically) comparing some 17 degrees per hour with 78x and 20 degrees with 68x (Pulanocular 30 mm without Paracorr). Even so, Ethos 21 mm makes my comet hunting session attractive and I think I will continue to using this eyepiece from now on.

Letfs get back to todayfs story. I got up at 2:30a.m. and the sky was clear. Five minutes after arriving at the observing site could began covering the sky. I hesitated to set up my comet-seeker because not only of increase in the amount of cloud but also of lightning with a clap of thunder that generated far away. I checked a radar image using a mobile phone and I confirmed there was no rain cloud near the site. I waited for the clear sky patiently for about half an hour, and finally I decided to set up the comet-seeker at 3:30a.m. since cloud began to disappear.

I began sweeping the sky from alpha Corvi. Clouds covered the search area many times, but I identified 12 DSOs in total including 13th magnitude galaxies: NGC3791 and 3866. I used 15x110 mm binocular from 4:50 to 5:08a.m., i.e. before the beginning of the twilight, that swept the area of some 30 degrees x 60 degrees (vertically x horizontally). I identified M5 and M104 with the binocular.

Employing super wide field optics, i.e. Ethos 21 mm for 46 cm Newtonian and 15x110 mm binocular with 6 degrees FOV, made the hunting session more enjoyable than ever.

Friday, November 21

Unexpectedly and luckily, we had many fine days in November, and I conducted comet hunting session six times so far in this month. On top of that, the transparency was the highest at this predawn throughout this autumn, though the wind was strong and seeing was moderate.

I began to sweep the sky from M104 at 3:55a.m. I identified 23 galaxies during the session. The most impressive object was NGC3852 galaxy group between the boundary of Leo and Virgo. I noticed three of them, NGC3852 (a magnitude of 12.8), 3848 (12.8) and 3817 (13.3) but the two stars I saw near the group were actually not stars but galaxies: NGC3819 (14.0) and 3820 (14.5). I noticed the fact at home in the evening when I checked them using a digital star map. The apparent diameter of those two galaxies were less than 1 arc minute and I could not recognize them as galaxies but as stars.

NGC3852 galaxy group (I do not know if this is the formal name). The field is 15 arc minutes.
The Digitized Sky Survey copyright © 1994

The apparent size of comet-like object is one of the major factors to notice it during the session. I used to omit many planetary nebulae because of the small size; I took them for stars. However, this is the first time I noticed that I mistook galaxies for stars. The other factor if one can identify comet-like object or not is, off course, the magnitude. I used the magnification of 68 when I discovered C/2002 E2 Snyder-Murakami, while I did 78 at the discovery of P/2010 V1 Ikeya-Murakami. I have never ever noticed Stefanfs Quintet with the magnification of 68 but I could recognized the group many times with the magnifying power of 78. Generally speaking, the higher the magnification is, the higher the chance of discovering faint comet becomes, if seeing is good. However, the area of the sky one can sweep decrease with increasing the magnification and note that the maximum magnification exists; in my impression it is three to four times of the aperture in centimeter for comets.

For this reason, I thought it is ideal to use both a large aperture telescope with high magnification and a small aperture telescope with low magnification in tandem. I bought a 15x110 mm binocular for this purpose and actually I spotted a possible new comet in 2004. I did not employed the binocular for a while but I used for 15 minutes at this predawn from 4:55a.m., five minutes before the beginning of the twilight. Beautiful thin crescent moon decorated by an earthlight passed through the FOV. At the dark night with high transparency I want to set up and sweep the eastern sky using this exquisite Russian binocular from now on. A new bright comet may appear at a low altitude like that of 2004 again.

I got back to the 46cm-comet-seeker with 78x again at 5:10a.m. and completed the session at 5:30a.m.

Thursday, October 30

There were many fine days during the latter half of October, and today was the 6th comet hunting session including October 18, the day of the first session in the month. I have continued the searching session every clear sky in spite of having been busy at work, and I have got ill for a while. Now I have almost recovered (on Nov. 3).

I trained my telescope at C/2014 R1 Borisov before the start of the session but I could not observe the comet probably due to the low altitude.

NGC3395, 3396, 3413, 3424 and 3430. Figures in the parentheses are the magnitudes. The field is 45f.
The Digitized Sky Survey copyright © 1994

On Saturday October 18, I swept the sky from Sirius, and I spread the search area northward session by session. Today, as a series of search since last time, October 26, I swept eobservation window of the universef in the constellations of Coma Berenices and Virgo. I began to search from M100 near where I finished the session last time. I introduced the galaxy using the digital setting circles but I could not see M100 even with 46 cm comet-seeker because of the low altitude of only 7 degrees. I aimed my comet-seeker at an altitude of around 40 degrees, and I moved it toward the horizon. Soon after the start of the motion, a pair of galaxies, NGC3504 (magnitude of 10.9) and 3512 (12.3) in the constellation of Leo Minor came into the FOV. In addition to bright zodiacal light, unsatisfactory air transparency dictated the limiting magnitude of galaxy to 12th magnitude; I could not identified the galaxy with the13th magnitude. After that I identified some other galaxies and then five galaxies with magnitude of 11th to 12th came across in the same FOV: NGC3395, 3396, 3413, 3424 and 3430. NGC3395, and 3396 are interacting galaxies. They were at an altitude of 35 degrees and the background was dark enough that made me feel they were floating on the universe and impressive.

In case that there were many galaxies in the same FOV, firstly, I identify one of them using the digital setting circles. Secondly, I look at the galaxy image using eDeep Sky Browserf, an appli of the iPod. The field size of the image is set at 1 degree or 30f and I compare the arrangement of the galaxies in the image with that in the FOV to identify the other galaxies. I used to turn the pages in the Uranometoria 2000 to check the galaxies but iPod is more effective.
C.f. Diary on Nov. 2, 2011
Deep Sky Browser

I identified and enjoyed showpieces in the constellation of Coma Berenices, M64 (Black Eye Galaxy), M54 (globular cluster) and NGC4565 (edge on galaxy). They all were at the low altitude but it was easy to observe eBlack Eyef in M64, to resolve M54 into stars and to see clear dark lane in NGC4564. Air temperature dropped down to 2 degrees Celsius but I did not feel very cold. I observed 26 galaxies and one globular cluster and completed the searching session at 5:10a.m., 30 minutes after the beginning of the twilight.

Saturday, October 18

I comet hunted for the first time at this predawn, as my workload has been heavy and the weather was unstable for those three weeks. It took longer time to set up my comet-seeker with my winter clothes, since cold suddenly set in. Air temperature dropped to 4 degrees Celsius.

Jupiter, the king of planet, and beautiful white moon led the constellation of Leo that rose on the eastern sky. Leo looked more majestic and stronger with Jupiter and the moon. Hydra rose with its long body and on the sky with Leo side by side.

Prior to the hunting session I observed C/2012 K1 PanSTARRS at 2:20a.m. The magnitude was 7th, with a diameter of 5f and DC was 4 by intuition, but it was not precise observation using reference stars. The tail was not observed due to moonlight.

Leo led by Jupiter and the moon.

I aimed my telescope at Sirius where I started the searching session. Even under the moonlight the Milky Way around Monoceros and Puppis was lovely and some unexpected DSOs were came across the FOV. The first one was NGC2316, a reflection nebula, which was nebulous and has only 0.3f of apparent diameter due to moonlight. I cloud manage to notice this object because it passed through near the center of the field. The next object was NGC2327 that looked like a star at a glance but it was surrounded by dim nebulous light. I myself felt that I could notice this challenging object. This nebula is the head part of Seagull Nebula. The third one was "Skull and Crossbones nebula", a combination of NGC2467and Sh2-311. This one has a large apparent diameter and I will never overlook as far as the sky condition is good. I think I identified this object in the past. NGC2438, a planetary nebula in M46m, looked bright and large. C/2012 K1 did not come into the FOV during the session as the cloud passed the search area at the low altitude.

From the left to right: NGC2316, the image is 5f wide, NGC2327, 10f, NGC2467, 15f.

At 4:30a.m. clouds covered in the southern and the eastern sky. I trained my comet-seeker at Ursa Major. I identified M51, NGC3898 and 3998 and completed the session.

Tuesday, September 23

The clear sky woke me up at 1:10a.m. JST, 30 minutes before the alarm clock rang. I experienced such a wake-up many times. I think my body sensor can detect changes in temperature and/or air pressure and lets me know the timing of wake-up. I have ever woken up suddenly, regardless of not setting the alarm clock; I did not set the alarm as I expected it would be cloudy at predawn. It happened the day when I discovered C/2002 E2 Snyder-Murakami. This predawn I got up at 1:30a.m., 20 minutes after my first wake-up as I wanted to stay a bit longer in my bed.

I comet-hunted on Sunday, September 21 under the clear sky, but it was not dark night as the crescent moon was shining. On Sunday, I could identify no comet like objects but I encountered C/2012 K1 PanSTARRS. Earlier than September 21, I swept the sky on Wednesday, September 3 and Thursday, September 4. On Sep. 3 seeing was extremely bad and stars swelled in the FOV with a lot of clouds. On Sep. 4, I was irritated by strong wind with frequent passage of clouds through my search area. This predawn it was cloudless and windless, and, I expected I would make an intense hunting session.

NGC2683, very elongated one in Lynx. The field is 15f wide.
The Digitized Sky Survey copyright © 1994

At 2:30a.m. I aimed my telescope at Pollux, Beta Geminorum, and started the session from this star. In a short time, Jupiter passed through the FOV and then Castor, a double star, did. I detected NGC2903, a galaxy in the constellation of Leo, with an altitude of 10 degrees above the horizon. The next galaxy that came into the FOV was NGC2683, very elongated one in Lynx followed by NGC2964-2968, a pair of galaxies, NGC2859, 3245, and 3021. The darkest one among those is NGC3021 with a magnitude of 12.2 referring to Guide 9, a digital map. However, I did not notice NGC3003, a magnitude of 11.5, which is seen in the same FOV with NGC3021. In my impression NGC2968 (magnitude of 11.7) was the faintest among those. The darkest galaxy in terms of the total magnitude is NGC3021, but the surface brightness of this galaxy is high with small apparent size.

I took a break and looked up the sky. Dignified and valiant figure of Orion, Leofs powerful upper half of the body that was about to rise above the horizon, elegant flow of the autumn and winter Milky Way and zodiacal light that was like a ray released from Leo; all were splendid form of the universe. Happiness that I could hear peaceful music played by insects in this gorgeous cosmic hall. In the past when there was no light pollution, everyone could enjoy such a wonder.

After completing the two hours of the session, I began to see the real world with the daybreak. The thin moon rose when I tool down my comet-seeker.

Saturday, August 30

It has been cloudy and rainy throughout August, and there occurred many flooding all over Japan. In my impression inundation hit at least one city every week. Obviously, the weather pattern is abnormal.

The number of times I comet hunted in August was only twice: Friday 1 and Saturday 2. Since then, I got up at predawn several times but every time it was cloudy. While we have cloudy and rainy weather, two comets that are expected to be bright were discovered. One is C/2014 Q1 PanSTARRS and another is C/204 Q2 Lovejoy. The magnitude at the time of discovery was 18.4 and 14.8, respectively. Both of them were not within reach of my comet-seeker, even if I take the fact that the brightness measured by CCD into consideration; CCD magnitude is darker than that of visual one by about two, though the reason of this difference is unknown.

C/2014 Q1 PanSTARRS may be seen by naked eyes in the next summer, while C2014 Q2 Lovejoy will reach 8th magnitude in January. No comet has been discovered visually since P/2010 V1 Ikeya-Murakami, but I believe visual discovery is still possible. I will wait for the clear sky patiently.

Saturday, August 2

Again, the forecast was completely off and the clear sky have prevailed since last dusk. I was preparing for todayfs session since last dusk. I went to bed at 8:50p.m. on Friday, and got up at 1a.m. this predawn. I drove to one of the usual observing sites. At the site the transparency was pretty good. The Milky Way was very impressive near the zenith. However, wind was very strong due to a typhoon and I set up my telescope near the lee side of a building to avoid wind force applied on the optical tube assembly.

I aimed my telescope at NGC596 that was the last galaxy I identified yesterday from where I started the session. It was very comfortable to sweep the sky, since dark back ground made shining of stars brighter and clearer; the transparency last month was poor and the back ground was not very dark yesterday due to light pollution. Once I pulled down my comet-seeker to the horizon, then I moved it up to the altitude of some 40 degrees from where I sweep the sky toward the horizon again. While I was moving my telescope upward, it took only several seconds, I sometimes looked at the sky instead of FOV; during the motion of only several seconds I accidently saw a bright satellite flash! It was brighter than -3 magnitude at 2:38a.m. At home it turned out to be Iridium 57 with the magnitude of -4.

Flash by Iridium 57 that I accidently witnessed. Click to enlarge.

Many galaxies came into the FOV and some of them were 12th magnitude. As a result I identified 17 galaxies and swept 34 degrees horizontally during one hour and 40 minutes. Though some clouds passed through the search area, it really was enjoyable and satisfying session.

Friday, August 1

The weather forecast was completely off the mark. It was rainy last dusk and I was unprepared to comet hunt. However, it seemed that my body sensor detected the clear sky and I suddenly woke up at 2:05a.m. when just one hour before the start of the twilight. I was in a hurry to go comet hunting. The observing site should be the nearest one: a farm land behind my residence.

Interactive galaxy, NGC274 (left) and 275. The image is 10f wide.
The Digitized Sky Survey copyright © 1994

I set up my comet-seeker as soon as possible and began to search the sky at 2:40a.m. from Deneb Kitos, Beta Ceti. I identified 8 galaxies during one hour and five minutes of the session: NGC157, 210, 274, 275, 337, 613, 584 and 596. NGC274 and 275 are interacting galaxy and it was easy to separate using my 46 cm comet-seeker with x78. Today I was happy to conduct the session unexpectedly.

Monday, July 21  (National holiday)

It had been cloudy, and finally, today I could conduct the first comet hunting session this month. The last one was Saturday, June 28.

At Sunday night the forecast predicted a cloudy sky throughout the night, and I was unprepared. I looked up the sky and noticed it was cloudless at 9p.m. JST. The forecast was off, and I went to bed as soon as possible. As a result, it was 10p.m. when I hit the hay on Sunday.

I got up at 1:50a.m. and set up my comet-seeker at a farm next to my residence. I trained my comet-seeker at Deneb Kaitos, Beta Ceti, and started the session from there. Thanks to excellent seeing, stars gave off innocent light that I felt like my mind was being drawn into. The place where stars are shining is where we are from and where we will go in the future. At 3:15a.m. cloud began to cover most part of the sky, and I aimed my telescope in the north-east where there was a gap among clouds. I completed the session in 10 minutes since then.

I was walking on the wood plate along a cotton grass (Eriophorum vaginatum) colony. You see snowpack in the background of the photo.

Bogs at the plateau near the top of the mountain.

After one and half hour of sleep, I headed for Mt. Naeba, 2145 m above sea level (a.s.l.), for mountaineering. I am not sure when I visited this mountain last, but I climbed it at least five times. After one hour drive from my house, my wife and I arrived at the parking lot with an altitude of 1310 m where we started to climb. Three hoursf walk brought us to the plateau, 2000 m a.s.l. from where beautiful wetland extending.
Today, we enjoyed great natural beauty and I was satisfied with the mountaineering in addition to the hinting session.

Saturday, June 28

There were two big cometary news this month. One is a passing away of Bill Bradfield, the great Australian comet hunter. Another is a detection of 72P Denning –Fujikawa by Hidetaka Sato. The comet was discovered by Denning in 1881 but had been missed until 1978 when Shigehisa Fujikawa re-discovered it. After Fujikawafs re-discovery the comet has been missed again. I am glad 72P was detected by Japanese observer.

The sky of this month had been cloudy at night while it was fine in some days only in daytime. I waited for clear sky and as a result I could conduct the second comet searching session at this predawn.
The first one was on Thursday, June 26, but the session was not satisfactory. On Thursday I drove to the new observing site where I made a preliminary inspection in daytime several days ago. I started the session at 1:35a.m. local time (JST) as the twilight began at 2:34. The site looked good at first. However, at 2a.m. dense fog was formed and grew quickly from Shinano-gawa River that is the longest river in Japan and flows through my city. The river is the major source of water vapor. Fog covered some 20 degrees above the eastern horizon and I could not search the eastern sky. I trained my comet-seeker to the north and identified NGC 3945, 5832 and 4605 during the session. At 2:55a.m. I got back to the eastern sky as fog disappeared and enjoyed observing C/2013 UQ4 Catalina for the first time. C/2013 UQ4 was bright, 10th magnitude with a bright nucleus.
I will never visit this observing site again. I read somewhere that Minoru Honda used about 20 observing sites. I also counted the number of the sites I used; it was over 20.

Today I greatly enjoyed the second hunting session this month. I went to one of the usual observing sites. I wanted to search the east but the eastern sky was covered with cloud. I aimed my comet-seeker at Mirphac, Alpha Percei, where there was no cloud, and began with the session there. Wind was strong and I felt it annoying but the sky was clear and seeing was rather good. Though I did not encounter any comet like objects, I was impressed by the beauty of the star field. There are many open clusters along the area I swept, in the constellation of Cassiopeia and Perceus. I was satisfied with the loveliness of these clusters. On top of that I took off during the session to observe M31 and M13 for a few minutes. The dark lanes in M31 were very clearly seen and I noticed some HII regions. M13 was jaw-dropping.

Image was produced using Stellarium

During the twilight Capella, Venus and Pleiades were above the eastern horizon. Before the time when I completed the session Seven Sisters were fading gradually and disappeared in the sunrise colors. Lovely daybreak.

Sunday, June 1

The total number of comet hunting sessions in May was 8, though there were much more days with clear pre-dawn. For example, it has been clear sky at pre-dawn for 5 consecutive days since Wednesday May 28, but I comet searched only on Wednesday and Thursday. The reason of less searching days was poor atmospheric transparency.

As I wrote on the last diary the concentration of PM2.5 correlates with transparency, but I experienced excellent transparency with PM2.5 of > 20 g/m3 that meant atmospheric transparency is not dictated by PM2.5 alone. I assume humidity may plays an important role on transparency in addition to yellow sand from the continent. I stop searching for three days, Friday May 30 to today, due to yellow sand from Chinese desert. This nasty condition will last at least a few more days.

Photo taken on December 30, 2013 with excellent atmospheric transparency (left), and June 1, 2014 with poor transparency because of yellow sand originated in Chinese desert (right). The mountain range 30 km away was not visible on the photo of June 1 (shown by a square on the left photo).

The most impressive session in May was that on Thursday, May 8. The sky was so clear that I was attracted by the summer Milky Way as search area, although it was at the meridian. I identified some 30 DSOs in the Milky Way. They included NGC6541, a 6th magnitude globular cluster in the constellation of Corona Australis. When I identified it I wondered if I have ever observed this cluster as the altitude of the cluster was only 9 degrees at the time of transit. Another impressive object was Barnard 289, a dark nebula, in Sagittarius. The contrast of dark nebula and the star ground with complicated structure was very clear.

Barnard 289. The image is 1 degree wide.
The Digitized Sky Survey copyright © 1994

I hope the recovery of air transparency before the start of rainy season that usually start early or middle of this month in my city.

Sunday, May 4

Atmospheric transparency

This is the second comet searching session in May. At the first session on Thursday May 1, I was satisfied with the excellent air transparency when I arrived at the site. Nevertheless, it was degraded to the moderate level with time during the session.
Yesterday, I got up at 1:15a.m. and drove to the observing site, however, contrary to the sky condition on Thursday, it was poor. I must give up conducting a comet hunting session; I got back home from the site at once without setting up my comet-seeker.
Today the atmospheric transparency was not bad but less than average especially near the horizon.

The haze that influences the transparency mostly originates from the continent. Specifically, yellow sand and other aerosols are the cause for poor transparency. I knew there exists a forecast for yellow sand , but I had no idea what kinds of aerosols other than yellow sand affect the atmospheric transparency. Recently, media publicizes that particulate matter 2.5 (PM 2.5) affects public health and that China releases a lot of PM2.5, though the fact has been known and the measurements of this material has been conducted since more than a decade ago. I must say the government tries to hide health problems caused by radioactive materials from Fukushima using such an announcement. Anyway, I have internet searched for the first time on the forecast of PM2.5 and spotted sites:

Changes in PM2.5 at Muikamachi 22 km ESE from the observing site.

Here is data on PM2.5 that corresponds to what I have experienced about the air transparency. On Thursday May 1 the transparency was excellent with the concentration of PM2.5 of 2
g/m3 at 3a.m. but it rose up to 6 g/m3 at 4a.m. At dawn on Saturday May 3 the values were large, 18 and 15 g/m3, at 1a.m. and 2a.m., respectively, and I went back home from the site before 2a.m. Today PM2.5 was around 10
g/m3 and the transparency was a bit less than average. Among those three days the contribution of yellow sand was obvious only on Saturday May 3. Overall the transparency seems to change with the concentration of PM2.5.

I am sure atmospheric transparency is governed at least by the concentration of yellow sand and MP2.5, though air contains various kinds of aerosols for which the forecasts are released from the abovementioned web site. From now on I will check out not only the forecast of yellow sand but also that of PM2.5 prior to the comet hunting session. I wondered if this kind of air pollution was so serious in my boyhood.

Letfs get back to todayfs story. During the twilight at 3:14a.m. I saw a bright satellite of the first magnitude was heading for the eastern horizon in the constellation of Pegasus. I presumed that it must be International Space Station. But it turned out to be the Chinese satellite gTiangong 1h when I investigated on it at home . Everything changes with the time.

Saturday, April 26

I have comet hunted four consecutive days at predawn since Wednesday. At the center of my city snow disappeared two weeks ago, and the climate is comfortable with full of flowers everywhere in the city. Now, many people feel it is the best season of the year.

Fukino-tou (Petasites japonicas, yellow flower), remaining snow and cherry blossoms around my office.

Unfortunately, though the crescent moon remained in the east at predawn, I enjoyed satisfactorily hunting session except on Saturday; the sky was hazy due to PM2.5 (particulate matter 2.5 from the continent). On Saturday, however, I took some photos. In spite of the poor transparency, the summer Milky Way is clear on the photos. Please note that the light pollution on the lower left where I stood, which was originated from Yuzawa-town with a population of only 8,300 (Photo 1, Figure 1).

Click to enlarge
Photo 1. Comet hunting session under the summer Milky Way.
Image was processed by MS-Photo Gallery. Canon 20Da, EF15 mm F2.8 (F2.8), 30 sec. ISO1600. April 26 2:24. 2014 (JST).

Figure 1. Light source around the observing site (from the diary on June 8, 2013). 

Photo 2. Light pollution caused by Yuzawa-town, 18 km from the site (lower left). The same photo with Photo 1, but non-image processed. Photo 3. Light pollution originated from Tohkamachi-city, 18 km from the site. The same photographing conditions with Photo 1. April 26 2:35. 2014 (JST).

Photo 4. Light pollution at Toda-city, Saitama, 18 km NW of the central part of Tokyo. Except for the exposure time (1 sec) and the date, photographic conditions were the same with Photos 1 to 3. March 28 19:34 2014 (JST).

Photos 1 and 2 are the same but Photo 2 was not image processed. Photo 1 to 3 were taken at the same site at the same predawn. Photo 3 was taken toward the center of Tohkamachi-city where a population of 57,600. One can see the degree of light pollution for Yuzawa and Tohkamachi on Photos 2 and 3, respectively. I myself was  disappointed at the seriousness of the light pollution caused by such small town or city to see the photos.

However, Photo 4, a shot near Tokyo, is more serious. The exposure was one second under the moonless condition but the sky is very bright. You can see Sirius at the center and Betelgeuse on the upper right.

Thank goodness I live under the dark sky.   

Photo 5. Moon, Venus and me. EF24-105 mm F4 (F4), 1 sec. April 26 4:15 2014 (JST).

Saturday, March 12

Luckily, I have conducted the sixth comet searching session this month at predawn today. When I set up my comet-seeker before 3a.m., the gibbous moon was still above the horizon. I enjoyed observing Mars that is at opposition on March 14 and Saturn before the start of the session, though seeing was less than moderate. On Mars Syrtis Major was apparent at a glance with a magnification of 290 but I wondered why the southern polar cap was seen instead of the northern one. I peered at the disk carefully again and I noticed a small northern polar cap while the white part in the south was not the southern polar cap but it looked white anyway. I checked the white part when I got back home and it turned out to be Hellas. The other conspicuous feature on Mars was bluish-white cloud on the east edge. Cassini's Division on Saturnfs ring was clear through round the ring, but the other features on the ring, e.g. C ring and Encke Gap, were not seen.

Mars. April 12, 2013 at 3:00 JST
Sotuh is up.@(c)@Guide 9.0

At 3:05a.m. the sky was getting darker as the moon declined and I began hunting from Antares. I encountered more than a dozen of globular clusters but the only exception was a planetary nebula in the constellation of Scorpius, NGC6153. It has an apparent diameter of only 0.4f but I could distinguish it from a star. If the seeing had been above the average it would be easy to detect it, but I could manage to do due to low altitude of the object, 13 degrees above horizon, and poor seeing.

At 3:20a.m. I noticed the battery of the digital setting circles died when an object that looked like a globular cluster came into the FOV. It was near the tail of Scorpius and it was easy to train my comet-seeker at the object again after changing the buttery and reset of the digital setting circles. I identified the object as a globular cluster, NGC6388, using the digital setting circles. However, I should know better. I had taken a note of the altitude and the azimuth of the object using the graduations on the circles (see photos below). If clouds had covered the object rapidly I could not identify the object.

Photos are from the diary on August 9, 2013.

Altitudinal circle

Azimuth circle

The sky was dark in a very short period of time, since the moon set at 3:20a.m. and the twilight began at 3:45a.m. Before 4a.m. the background in the FOV was getting brighter as twilight proceeded like that under the moonlight one hour ago. I enjoyed the last hunting session before the full moon.

Friday, March 28

This is the second comet hunting session in March. As I wrote last diary, I could not conduct the hunting session on March 4 due to the trip, and I was unable to do either because of a cold on Monday, March 24. On Tuesday, March 25 I could manage to conduct the first comet searching session this moth under the crescent moonlight, but my health condition was not very good.

Today, I almost recovered and the moon was rather thin. Before the start of the searching session, I observed C/2012 K2 PanSTARRS for the first time. It was 9th magnitude with d = 3f and tail = 2f by intuition. Then I trained my comet-seeker at M9, a globular cluster, in the constellation of Ophiuchus, and started the session from this object, since I completed the session near this area on Tuesday. I encountered as many as 23 DSOs during the session. Most of them were globular clusters including showpieces in the summer Milky Way like M20, M8, M22 and M17. NGC6445, a planetary nebula, and NGC6440, a globular cluster, in Sagittarius were in the same field of view with an angular distance of 22f. I always notice this pair when I search the area. I was impressed by the brilliant stars in the Milky Way.

At the start of the twilight I observed two more comets. C/2012 X1 LINER was 8th magnitude d = 3f and tail = 2f, while C/2013 R1 Lovejoy was 11th magnitude d = 1f with tail = 3f. Those two comets were still bright!


The square shows the area I swept with 46 cm x71.

I completed the session at 4:45a.m. when the crescent moon and Venus rose above the horizon.

Tuesday, March 4

It must be a clear sky this predawn but I could not comet hunt. I had been in a collage in Ishikawa Prefecture to give a scientific presentation as a forest hydrologist. How unlucky it was! I comet hunted last on February 12 and there is no prospect I can do it in a coming week.

This winter I went on a skiing many times. It is only 15 minutesf drive to the nearest ski field from my residence. If I am lucky I can ski along a beautiful beech stand.

My ski trail (left) along the beech stand.

During my skiing session I spotted a wonderful artwork of snow. We call it Yuki-Makuri, a rolled-snow if I translate it into English directly. A piece of snow that falls down from a tree rolls down along a slope and produces such an interesting shape under a certain condition. The diameter of Yuki-Makuri shown below was around 50 cm. This one is the finest one I have ever seen.

Yuki-Makuri, a rolled snow. Some 50 cm in diameter. Those photos are the same Yuki-Makuri but the angle of the shots were different.

Skiing is a wonderful sport for fitness since one can enjoy not only exercise but also beauty of winter nature.

Wednesday, February 12

At 3:25a.m. I arrived at the usual observing site. The sky was crystal clear with a biting cold. Air temperature was -8 degrees Celsius but I felt a sense of fulfillment as I could have the second searching session in February. At 4a.m. I competed setting up my comet-seeker but I was clouded out. I believed the clear sky appeared again and waited for a while. At 4:15a.m. stars began to shine on the southeastern sky and I started comet hinting near alpha Librae.

The first DSO I encountered was NGC5824, a 9th magnitude globular cluster in Lupus. The next one was NGC5796, 11th magnitude galaxy in Libra, but at the next moment I notice a companion of the galaxy, NGC5793. The magnitude is 13th and I could not recognize it without observing NGC5796. The third DSO was a pair of galaxy in Libra, NGC5898 and 5903. Both of them are 11th magnitude. I was moved when the showpiece of the constellation of Libra, NGC5897, a globular cluster, came into the FOV. It looked larger in apparent size as I peered it for a moment because I could detect fainter stars in the cluster, and the stars in the cluster were beautifully resolved!

NGC5796 (upper galaxy) and 5793. The image is 8f wide.
The Digitized Sky Survey copyright © 1994

However, the happy time did not last through the session. At 5a.m. clouds hid the eastern sky, and I searched on the north and on the northwest seeking the gaps among clouds. At 5:20a.m., 10 minutes after the beginning of the twilight, I finished the session and enjoyed observing Saturn through the cloud. The well-opened ring shined bewitching blue.

Tuesday, January 28

This was the third comet hunting session in January, and it is lucky enough to conduct the sessions as many as three times at mid-winter here in heavy snowfall area. The snow depth around the observing site was 180 cm that is norm.

I got up at 3a.m. and drove to the site. The counter grow was visible as I arrived at the site several minutes before the moonrise. I trained my comet-seeker at Saturn and started the session from there at 4:05a.m. Soon, the eastern sky became gray due to moonlight and the crescent moon with beautiful earthlight rose.

The first DSO I identified was NGC5812, a galaxy in the constellation of Libra. I could manage to distinguish this galaxy from a star, but if it passed through near the edge of the FOV it was difficult to do because of poor seeing; star image was swelled. The other all DSOs I encountered were globular clusters.

While I was sweeping the sky I encountered a beautiful pair of stars: beta Scorpii, yellow primary and light blue companion. Both stars looked like dancing due to bad scintillation that made them more attractive.

At the start of the twilight I observed tow comets. C/2013 R1 Lovejoy was still bright remaining 7th magnitude with a tail of 0.5 degrees long. C/2012 X1 LINEAR was 9th magnitude and the tail length was 0.2 degrees.

I got back to the session after observing the two comets. The earthlight on the moon appeared mysterious in the FOV, while Venus was shining ostentatiously, elegantly and gracefully just above the horizon. I looked up the eastern sky. How gorgeous it was! Mars, Saturn, Moon, Venus, Spica, Antares, Arcturus, Vega, Altair and Deneb! Beautiful dawn.

Wednseday, January 1

A happy New Year to you.

This is the first time I stay here in Tohkamachi on January 1 since I began to live here nearly 13 years ago. Usually, I went back to my motherfs house or travelled somewhere.

The sky was clear this predawn, though the cloud cover increased up to 80% for a while during the comet hunting session.
Prior to the comet hunting session I observed C/2013 V3 Nevski that has just passed the meridian with an altitude of 85 degrees above the horizon. The comet was extremely diffused, and one might overlook under the poor sky conditions.

I stared the session at 4:30a.m. local time, about one hour earlier the beginning of the twilight. I wanted to begin with the eastern sky, but the cloud hid the eastern sky and I was forced to search the southeast.

 NGC4783 (upper galaxy) and 4782. The field size is 7fx7f.
The Digitized Sky Survey copyright © 1994

I aimed my 46 cm comet-seeker at M104 and started the session from this galaxy. After a while, I encountered a pair of interacting galaxies, NGC4783 and 4782. I thought I must have identified this pair ever, but I could not remember I have surely observed them. Only 13 minutes after the start of the session, the cloud moved to the search area, and I stopped the session for three minutes. As the cloud passed through the search area I resumed the sweeping soon but in 12 minutes I must train my telescope at the west because all the eastern sky was covered by the cloud.

NGC5035, 5037, 5044 and 5047.
The field size is 30fx30f.
The Digitized Sky Survey copyright © 1994

In eight minutes I aimed my comet-seeker at the SE again, since the cloud cover at the SE sky reduced. It was impressive when four galaxies, NGC5035, 5037, 5044 and 5047 came into the same field of view (FOV). Surprisingly, I did not notice NGC5054 that was 10th magnitude galaxy in the same FOV. I guess this is because surface brightness of NGC5054 is darker than the four galaxies.

At the time of the twilight clouds in the eastern sky disappeared and I observed C/2013 R1 Lovejoy and C/2012 X1 LINEAR. C/2013 R1 got darker but the tail was clear, while C/2012 X1 remained the brightness and the degree of concentration for over one moth.

I resumed the session during the twilight and encountered M83 that looked like a comet with a large coma and the bight nucleus. It reminded me of P/2010 V1 Ikeya-Murakami. I wondered where this comet traveled.

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