Sunday January 3, 2016 - Email Exchanges with Meteorobs

  Just after getting back inside from my meteor watching session on Sunday morning, January 3, I emailed a short message to the meteorobs group (meteorobs@meteorobs.org) to report what I'd seen (and not seen). This is what I wrote: 

  Kind of a disappointing morning here. I was outside from 7:30 - 9:00 UT January 3 with a clear sky and LM = 5.1 before moonlight started to wash out the faintest stars, but I didn't log a single Quadrantid. Three meteors total ... 1 Alpha Hydrid (+2.0 mag.), 1 Anthelion (+2.0 mag.) and 1 Sporadic (+1.0 mag.) Just below freezing with a breeze making a wind chill that was several degrees colder. I hope the rest of you have better luck! We're forecast to have clouds and scattered snow flurries for the Quadrantid peak on Monday morning.

  After waking up, I was surprised to get a response from a veteran meteor observer I'd read about, Richard Taibi from Maryland. Richard has been very involved with the American Meteor Society since 1983, and receiving personal email from him was very encouraging. This is what he wrote, and the reply that I wrote back to him that afternoon.

Hi Paul,
I am a sometime meteorobs poster.  I applaud your effort this morning to watch the QUAs.  I considered doing the same but was too tired (getting old!) to do so.
I appreciate getting your report on what I might have seen and (not seen) if I had been as intrepid as you.  My weather forecast is better than yours for tomorrow morning and if it proves to be good, I'll go look and post results on meteorobs.
Best wishes for the new year!
Rich 

Hello Richard, and thanks for the kind words.

  Best of luck to you tomorrow morning! I guess the experts aren't kidding when they write that the QUA shower has a quick rise and fall around maximum. Either they were quiet this morning or I missed every one. (I always have this feeling all the best meteors are shooting through the sky behind me whenever I get out to observe!) Best wishes to you as well for the New Year!

  Paul Z

  There were other replies to my original message as well. One interesting response came from "Anthony" somewhere in the Eastern Time Zone. Unfortunately, that's all I know about this writer: 

Hi all,
 The Quads are strange. I've attempted them for many years (as long as the clouds stayed away). Most of the time, I've been clouded out. Some clear years, the peak wasn't favored in my time zone (EST USA). But Paul,  I'm not surprised you didn't see any.  That sharp, narrow peak is true to it's word. I've nailed the peak one time in those years. ONE TIME! Before and after, almost no activity.  It's great if you can hit it. This year, I'm favored again, and it should be clear out!
 Crossing fingers!
Anthony

  As far as the Quadrantid peak itself before dawn on Monday, January 4, I ran out of luck. A cold front passed us on Sunday evening, and after midnight we had overcast skies and light snow flurries falling, putting a very light dusting on raised surfaces and some thin patches on the ground. Streamers of very light snow showed up on radar from Lake Michigan through Central Indiana. It was the first snow event of the year, and though it wasn't a storm by any means, it ruined any chances of me observing that narrow peak of this tricky annual meteor shower. 

  I DID end up sending a report of the three meteors I saw to the International Meteor Organization about two weeks later; reasoning that even a negative report (as far as Quadrantid activity) could be valuable to them. 

AM Sunday January 3, 2016 - Meteor Observing Notes

  Beginning of Session: 2:30 AM EST (7:30 UT Jan. 3)
  End of Session: 4:00 AM EST (9:00 UT Jan.3)
  Location: Backyard patio at home.
  Longitude: 86° 03' 01" W.
  Latitude: 39° 39' 39" N.
  Elevation: 255 meters.

  Observed Showers:
  Anthelion (ANT) 115° (7h 40m) +20°
  Alpha Hydrids (AHY) 128° (8h 32m) -08°
  January Leonids (JLE) 148° (9h 52m) +24°
  December Leonis Minorids (DLM) 174° (11h 36m) +24°
  Quadrantids (QUA) 229° (15h 16m) +50°

  Center of F.O.V.: 150° +60° (Between Omicron Ursae Majoris and Alpha and Beta Ursae Majoris.)
  Teff: 1.416 Hours (1 hour 25 minutes of uninterrupted viewing.)
  F: 1.000 (No clouds or obstructions.)
  LM: 5.13 mag. (8 stars definitely seen in Area 3 in Ursa Major. Because of moonlight interference, this was probably 5.0 - 4.8 mag. during the last half hour, but no meteors were seen then.)
  Observing Type: Counting only; no plotting. Used Note-Corder.
  Weather: Very clear. No clouds. Breezy and cold. Some moonlight interference from 3:35 AM through the end of the session.
  (See Detailed Notes)


  3 Meteors Seen

  (Time / Type / Magnitude / Speed / Wake - Train - Color / Comments)

  1. 2:56 AM EST (7:56 UT Jan. 3) / Sporadic / +1.0 / 4-5 / No Wake, No Train, Yellowish Color / This fast meteor whizzed from the Bowl of the Big Dipper to the area of Mizar in the Handle of the Dipper. It was moving totally in the wrong direction for a QUA.

  2. 2:57 AM EST (7:57 UT Jan. 3) / ANT / +2.0 / 3 / No Wake, No Train, No Color Seen / This seemed to come from the general direction of Gemini. Though the speed seemed a little fast for an Anthelion, I'm fairly sure that it was a far-flung member of this group.

  3. 3:27 AM EST (8:27 UT Jan. 3) / AHY / +2.0 / 3 / Short Wake, No Train, No Color / This meteor "beaded" before vanishing, or possibly split into at least two fragments. It zipped north of Auriga and Gemini and I'm 90% sure that it came from the Alpha Hydrid radiant area. This was probably my first sighting of an AHY!


  Detailed Notes 

•   With the Sporadic meteor seen the previous morning (4:04 AM EST Jan. 2 / 9:04 UT Jan. 2) I've already logged 4 meteors total for 2016, just three days into the new year; 2 Sporadics, 1 Anthelion, and 1 Alpha Hydrid. 

•   I saw NO QUADRANTID METEORS AT ALL this morning, though the I.M.O. prediction for the maximum of this shower was just 24 hours away (3:00 AM EST Jan. 4 / 8:00 UT Jan. 4). I realize that this annual shower is known to have a very sharp rise and fall in numbers, but this was still surprising. Observing early Quadrantid meteors was my main goal. 

•  As I mentioned above, I did no plotting tonight. The intent was to watch for meteors and assign shower membership through speed and direction.

•   I actually had a first session outside this morning between 1:00 AM and 1:45 AM (6:00 - 6:45 UT Jan. 3) but I saw no meteors at all, and went back inside to warm up. I'd hoped that I'd just been outside too early, with the radiant of the Quadrantid Shower too low on the horizon. 

•   I observed from the lawn chair on the patio just outside the back door of our house. I was bundled up in "full winter gear" with sweat pants under my jeans, a sweatshirt under my winter coat, hat and gloves, and hand warmers inside my gloves. By the end of the observing session my fingertips were aching but the hand warmers inside my gloves definitely helped. But, in the future, toe warmers may not be a bad idea! My feet ended up feeling like blocks of ice and my legs also felt very cold. I was shivering a lot by the last half hour. I was pleased to see that my Note Corder batteries survived the cold very well. I kept it in my coat pocket covered up by my glove when I wasn't talking into it. 

•   Throughout this observing session the sky remained very clear with no clouds seen at all. There was enough of a breeze that I felt it now and then, and it was even enough to rustle the cover on our backyard grill now and then. There was no snow cover anywhere. I smelled chimney smoke in the neighborhood; this may have "murked up" the sky just a little.

•   2:00 AM Conditions: 31°F, Wind SW at 14 mph, Wind Chill 21°F, Dew Point 24°F, Humidity 76%, Pressure 29.96".

•   3:00 AM Conditions: 31°F, Wind W at 12 mph, Wind Chill 22°F, Dew Point 24°F, Humidity 76%, Pressure 29.98".

•   4:00 AM Conditions: 29°F, Wind W at 10 mph, Wind Chill 20°F, Dew Point 23°F, Humidity 78%, Pressure 29.98".

•   When I started observing there was a dog barking somewhere close by in the neighborhood, but it quieted down. I also heard the sound of howling in the distance that I first thought might be Coyotes, but decided later that they were (probably) also dogs. Besides these noises there was the usual hum of traffic from I-65. It was a very quiet winter night. I saw one high-flying aircraft but no satellites.

•   The Moon was a "fat" Waning Crescent in Virgo, about 26 hours past Last Quarter (Last Quarter was at 12:30 AM EST Jan. 2 / 5:30 UT Jan. 2), 40% illuminated. Moonrise itself took place around 1:50 AM EST. Throughout the first half of the session the ESE sky showed more and more of a glow. The Moon was visible over the roof of our neighbors' house to the SSE by 3:35 AM (over the peak of their roof). For the last half hour I tried to use the hood of my coat to block it from my field of view. 

•   The entire Big Dipper and Jupiter (in SE Leo) could be seen over the roof of our house when I started observing. Arcturus could be seen over the roof by 3:13 AM (with me lying on the lawn chair). The Moon (as I wrote) was visible from where I was lying by 3:35 AM. By the end of the session at 4:00 AM the Moon (with visible Earthshine) was nicely framed between Spica and Mars low in the SE sky. I drew a very rough sketch of how it looked:

AM Friday, January 1 and AM Saturday January 2, 2016 - Predawn Visual / Binocular Observing / Sporadic Meteor Observation

  On the morning of New Year's Day (Friday January 1) skies were mostly cloudy at midnight and cleared slowly during the hours before dawn. I was able to catch the Waning Gibbous Moon shining several degrees east and a little south of gleaming Jupiter, which was itself in far southeastern Leo, when I was outside around 2:30 AM EST. I made a very rough sketch of how they looked in a spiral notebook. It was a cold and breezy night with the temperature in the mid-20's degree F range and a Wind Chill in the mid teens degree F range. Here's the sketch I made that morning (as I wrote ... it was VERY ROUGH!

  The following morning, Saturday January 2, skies cleared out again, and I was outside around 4:00 AM. Jupiter was again shining brightly near where I'd seen it the previous morning (of course) and the Moon was now Waning, just hours past Last Quarter (Last Quarter had actually taken place at 12:30 AM EST on January 2). The Moon was further east between the "tail" of Leo and the star Spica, and a little Earthshine was visible on it, especially when viewed through 7X50 binoculars. Mars was also shining just east of Spica. I made another rough sketch of this in the spiral notebook:

  At 4:04 AM (9:04 UT Jan. 2) I also spotted my first meteor of the year! It was Sporadic, 2.0 magnitude, Speed = 4, No Wake, No Train, No Color. It passed quickly from near the "handle" of the Big Dipper to an area north of Bootes. It was too swift and totally going in the wrong direction for me to think it was a Quadrantid, and I don't know of any active minor meteor showers that it could have belonged to. Again, here's a very rough sketch that I made that night:

  I went outside again around 4:30 AM EST with those same binoculars to get some looks at the Moon, Mars, and Corona Borealis (In case T CrB was having a flare up, or R CrB had brightened enough to be visible. I saw neither star). I also did a quick binocular search of an area just north of Arcturus to see if I could spot Comet Catalina C/2013 US10, but I couldn't pick out anything that looked comet-like. Everything I saw looked like faint stars. Moonlight may have also been interfering with picking it out of the background, if I saw it at all. This comet, the last I read online, was at about 6.5 magnitude, so it would have been difficult through these anyway. I vowed to try again in a week or so when moonlight wasn't an issue, as this object made it's way toward the "handle" of the Big Dipper. 

  It was a clear, moonlight, freezing cold night. No snow was anywhere. By the time I was done the temperature was in the upper 20's degree F range with a wind chill in the upper teens degree F range. 

September 2015 Variable Star Work and New Telescope Problems

  I was outside with the 10" F/4 telescope during four mornings in the middle of September and ended up doing a flurry of variable star estimates, including some YSO stars that I've observed in past years and some stars that were on Mike Poxon's list of Eclipsing Binaries that are suspected UXOR stars. (For the latter I'd requested charts with comparison stars from the AAVSO Charts Team; sometimes just days before.) I reported 31 estimates made over those four nights to the AAVSO, and my lifetime total of AAVSO estimates topped 2,000. 

  That's the good news; the bad news is that I still have dozens of estimates made between 2011 and this year that are scattered around in various notebooks, and even on the digital voice recorder, that I still haven't organized and reported. I still need to do that. But these September estimates WERE all entered into the database, and these were my first variable star observations since last May. So at least I ended the October 2014 - September 2015 AAVSO Fiscal Year on a good note.

  I won't go into detail here about these nights in September or all of the past years. I'm going to try to get all of those organized and report the estimates that still need reporting "on the side" instead of doing it on this blog. As far as this blog, I'm going to start "fresh." A new AAVSO Fiscal Year started on October 1st, 2015. And I'm going to make it my goal to report variable star estimates as they occur and keep up from this point on.

  However, I do have to write that during the last night that I did variable star observing, the predawn hours of September 22, I also realized that my 10" F/4 mount was "finished." I'd find a variable star, and then when I was trying to make an estimate ... maybe because I moved the control panel around ... the motors on the mount would suddenly turn on like they had a mind of their own and slew the telescope away from the star field I was looking at! It happened several times and it was frustrating as hell!

  I've had a love/hate relationship with the mount of my Meade LXD55 almost since the day it arrived in November 2002. I could never get the GOTO program to work correctly even though I followed the directions for aligning it as best I could. I gave up on it and tried to just manually move it to targets, but then the Right Ascension gear wheel came loose after just a few uses, making the motor run but keeping the scope from moving east to west (or vice versa) and keeping it from tracking the sky. I did quick fixes to it, but it would keep coming loose, and I never resolved that problem until I replaced the tiny inset screws that held the gear wheels in place in 2005! And by that time the silly little plastic clamps that locked and unlocked the two axes of the mount had broken off, leaving it locked, and moving the telescope with the motors was my only option. The mount always had to be plugged in to move!

  Even with these frustrating issues, I managed to get the mount to work well for the next four years or so, but a new problem happened around 2009 when it just stopped tracking! Engaging the drive caused the telescope to move quickly in the wrong direction! So I just stopped trying to get it to track the sky, and I would "nudge" it with the control pad to try to keep up with the Earth turning. And that worked from 2009 through now.

  I have had issues with the LXD55 mount for all of these years and found ways to overcome these problems, but to summarize, it's really never worked as advertised. And I'm not alone. I've read online posts for years from other LXD55 owners who are constantly fixing their mounts and finally getting rid of them in the end. Meade itself repackaged the LXD55 with a new mount after a few years and called it the LXD75, but then stopped making these telescopes altogether a few years ago.

  But these latest issues in September were the last straw. Let me make a short list of "grievances" and then present what might be some near-future solutions: 

   The 10" scope had always been tough to set up because of that awkward heavy mount. It was a back-breaker!

  It always had to be near the outside outlet by the back door because it always had to be plugged in to a power source to move. (Incidentally, the outlet itself stopped supplying power at the end of September!)

  Though I didn't mention this before, both the main cord to the mount and the cord of the control paddle are frayed with exposed wires, and I've had to tape them for a couple of years. Electrical shorts were always possible.

  The design of the mount meant that the eyepiece was often in a terrible position for me, making it necessary to either become a contortionist to look through the telescope or (what usually happened) making me loosen it up and rotate the tube to a more comfortable position.

  The little finder scope has always seemed inadequate and is always in an awkward position!

  So now here are a couple of possible solutions:

  Last in June I found a website that has a post from 2012 from an amateur astronomer named Dan Demmers who had acquired an LXD55 (I'm assuming from the photos it was a 10" Schmidt-Newtonian) from his older brother, and both had experienced similar issues with it that I've experienced. Dan decided that he either needed to modify it or get rid of it, and he ended up (among other things) putting it onto a wooden Dobsonian mount. The website and post are at tulareastro.org/meade-lxd55-facelift/.

  Dan bought the mount for his scope from a company that custom makes these for OTA's. The company website is www.astrogoods.com. I looked over this site and sent some questions about the weight of the mount, and received prompt replies from Mark Wagner on June 29 and 30. A collapsible mount with clamshell rings, he estimated, was about 30 pounds (compared to the weight of the current mount of 55 pounds) (the OTA of my telescope is about 30 pounds also). His mount would run about $480 total.

  The new mount would be more portable, and it would keep the eyepiece at a desirable angle. It wouldn't track the sky, but my current one hasn't done this in years anyway. It would still require two trips to set up the scope but it wouldn't have to be plugged in and I could set it up anywhere. This sounds like the direction I'll be going in.

  One final note, I also found a site called www.scopestuff.com that sells many telescope accessories, including a 7x50 right angle correct image finder scope that, I think, I can make work with my 10" F/4. It should keep the finder eyepiece at a good level and make targets easier to acquire.

  More on all of this later ... I'm hoping that through this winter I'll refurbish the 10" telescope, and by late winter or spring I'll resume an active AAVSO program.

  Until then, I'm going to finish 2015 by concentrating on meteor observing. The Orionid and Taurid showers, the Leonids, then the Geminids and Quadrantids. That should keep me busy until a little past New Year's Day 2016.

AM Saturday, September 12, 2015 - Notes

  During the short work week between the mornings of Tuesday, September 8th - Friday, September 11th the sky conditions didn't cooperate too well with my observing plans. This unusual stretch of hot and humid weather we'd been experiencing all month was changing as two slow-moving cold fronts passed through our area. I'd get some clear skies on some mornings, and get glimpses of the rising Winter Constellations. But there were usually scattered thin clouds around and light fog in the air, and the patio was usually damp from light showers that had fallen during the previous evening. I didn't think it was worthwhile to get the telescope out and try to observe under these circumstances.

  The second cold front of the week moved through during the day on Friday the 11th, and it was a cool, misty, sometimes rainy day with low, gloomy clouds everywhere. By the time I was driving home around 2:00 AM on Saturday the 12th, however, the rain had been over for hours and the sky was clearing out. A steady breeze had dried out the pavement a little and also kept a lot of low fog from forming. I thought that maybe my chance to observe variable stars was finally here. But every time I checked outside the back door between 3:00 AM and 5:00 AM, I was discouraged. Low clouds continued to march across the sky in waves (altocumulus and raggedy-looking cumulus) and the pavement of the patio was still damp. (This is always a concern since I plug the mount into the outdoor socket and the cord lies on the concrete.) Though it was mostly clear, I still didn't think it the ground and sky conditions merited taking the 10" scope outside.

  I stayed up very late, and went outside around 6:10 AM. At this time the sky had cleared dramatically! I believe the limiting naked eye magnitude was at least 5.0 since I could see a lot of the fainter stars in Orion, Taurus, and Gemini that I normally can't see in this light-polluted area. The sky to the East and Southeast was very dramatic. Though I've seen Orion several times in the morning sky over the last month, this morning it was high in the sky and dramatic, with Rigel and Betelgeuse blazing away. I could even make out the Orion Nebula (though, of course, it looked star-like without optical aid). I also had my first looks of the season of Procyon and Sirius sparkling away. At this time there was just a hint of the first light of dawn in the east. The temperature in the low 50's°F and it felt very chilly in comparison to the past several mornings. The sounds of singing insects were very subdued.

  However, the really showy object was Venus! This was my first look at it as a morning object; I'd last seen it low after sunset in July. It was so much brighter than any of the stars that it just looked unreal, like it was on fire! It was just peeking over the edge of the roof of our house from the edge of the patio.

  I drew a very rough sketch of how it looked below, though this drawing really doesn't do justice to how pretty it really looked:

  If I'd stayed up slightly later and had a better look at the eastern sky, and especially if I'd had binoculars handy, I probably could have also spotted Mars just 10 degrees or so to the lower left of Venus. And by 6:30 AM (though the sky would have been getting very bright at the time before sunrise) Jupiter also might have been glimpsed, just rising over the horizon, below and to the left of the star Regulus in Leo. This would have been a challenge, though, and almost certainly would have required binoculars. The Moon rose this morning just half an hour before the Sun, and it probably wouldn't have been visible in that very bright, very low eastern sky even with binoculars.

  New Moon occurs at 2:41 AM EDT Sunday September 13 (6:41 UT September 13). There is also a Partial Solar Eclipse at that time, but, of course, nothing of it will be visible from Indiana or anywhere near North America. It will be seen from South Africa and part of Antarctica.

  Venus will continue to blaze away in predawn skies from now through the whole winter, and even through May of 2016 (though it will be getting very tough to see by early Spring). In late October it will have a showy conjunction in Southeastern Leo with Jupiter and Mars. I'll keep watching the show when I can and try to add more sketches as time goes by.

AM Friday, September 4, 2015 - Lunar Observing / Imaging

 
  After coming home from work once again during the wee hours of the morning, and finding the sky once again mostly clear but murky and moonlit (pretty much like every predawn these first days of September) I decided to get the telescope out again to do some lunar observing and camera work again.

  The Moon was still a Waning Gibbous, but it was getting closer to Last Quarter. This time it was in far Eastern Taurus, higher in the sky, and shedding a little less light than it had three mornings ago. Though it was hazy and there may have been high fog in the air (and also still maybe a little high altitude smoke), Transparency was better than it had been on Tuesday morning this week. This time, 3rd magnitude stars could barely be seen, though anything dimmer was impossible with the naked eye.

  I had the 10" f/4 outside and set up by 4:05 AM, and at that time I also had a look at the Moon under 39x. I wasn't really trying to image any particular targets tonight; I just thought that Mare Imbrium might start looking interesting with the sunset line halfway through Mare Serenitatus and slowly heading its way.

  Lunar Colongitude at 4:15 AM (8:15 UT Sept. 4) = 159.48°
  Lunar Colongitude at 4:30 AM (8:30 UT Sept. 4) = 159.60°

  This time, unlike Tuesday morning, I only spent one short session outside between about 4:15 AM - 4:30 AM. During that time I managed to shoot 7 photos using 39x power and 36 photos using 78x power. These photos were downloaded into Folder #69 in my Nikon Transfer folder on my laptop.

  These are the best images of the session from what I've seen so far. All of them were taken using the Nikon Coolpix L20 digital camera handheld to the eyepiece of the telescope. I'm posting them here without much comment; obviously the Mare Serenitatus area and the heavily cratered highlands on the southern hemisphere were the most showy targets; though some shading can also be seen in Mare Imbrium's features and even on Plato. All in all, I was pleased with how the photos turned out! Once again, Seeing was great even though Transparency wasn't good at all!

  The image below is of the whole Moon. 39x power. 4:18 AM (8:18 UT Sept. 4). Lunar Colongitude = 159.51°

  The next image below shows the Moon's northern hemisphere under 78x power. 4:23 AM (8:23 UT Sept. 4). Lunar Colongitude = 159.55°

  This last image shows the heavily cratered lunar southern hemisphere. 78x power. 4:27 AM (8:27 UT Sept. 4). Lunar Colongitude = 159.58°

  I had the telescope back inside by 5:00 AM after what turned out to be a very short session. There was some dew on the telescope tube and dew cap, but, like Tuesday morning, I didn't really have it outside long enough for it to be an issue. Singing night insects were in full chorus again this morning.

  5:00 AM Conditions - Temperature = 72°F, Dew Point = 66°F, Humidity = 82%, Wind = SW at 6mph, Pressure = 29.98".

Tuesday September 1, 2015 - More on the Mare Crisium "Sunset Ray"

  Tuesday morning's observing / imaging session of the Moon was  a memorable one for a couple of reasons. Ever since viewing and sketching the "sunset ray" on Mare Crisium twice in 2008, I'd never seen this feature since, so this was the first time I'd seen it through the telescope in over seven years! And this was in spite of several attempts. It was also the first time I'd ever photographed it. I seemed to have caught it right at the beginning, so it also gave me a much better idea of when the effect on Mare Crisium starts. Here's a rundown of what I know so far from photographs and sketches:

Lunar Colongitude = 121.49° March 8, 2015 3:20 UT

  The photo above was taken early last March, at a time when the mountains along the southern rim of Mare Crisium first started to cast shadows on the plain. It was obvious even when I took the photo that it was still some time before the "sunset ray" was really noticeable.

Lunar Colongitude = 122.63° September 1, 2015 7:41 UT

  My first set of photos from Tuesday morning really made the situation clear. It shows this area of Mare Crisium at the equiv 2 hours 15 minutes after the first photo. Those mountain shadows were much more stretched out, but it's also clear in the photo (and I also saw this through the eyepiece) that the mountain shadow to the north hasn't quite reached the terminator yet, so even at this point there wasn't a cut-off lit-up area in between those shadows.

Lunar Colongitude = 123.06° September 1, 2015 8:34 UT

  The photo above shows this area just 53 minutes after the previous one, and by this time the northern mountain shadow had reached the terminator; making a true "sunset ray" in between. So now I know that the complete cut-off sunlit area starts around the time that the lunar colongitude lies at about 123°. This was the other real personal discovery on Tuesday morning before dawn!

Lunar Colongitude = 124.2° Sketched August 19, 2008 7:30 UT

  Now that I have pretty much pegged down the start time of this monthly lunar phenomena, my main mission in the near future is to find the "end time" and hopefully photograph it. The sketch above was from the second time that I've ever seen the "light ray" in 2008, and I recorded the colongitude then as 124.2°, which is the equivalent of about 2 hours 15 minutes after the last photograph. At the time, the "light ray" seemed narrow and even more detached from the rim of Mare Crisium. (I'd love to get a photograph of it looking like this some day!)

Lunar Colongitude = 129.37° March 30, 2013 5:38 UT

  Finally, this photograph shows the lit-up rim of Mare Crisium with the Mare itself all in shadow. It was taken at the equivalent of about 12 hours 30 minutes after the photograph taken when the colongitude was 123.06°. It's obvious at this point that the "sunset ray" is long gone. This photo gives me an extreme upper limit to how long it lasts, but until I make more observations of the Moon between when the terminator is between colongitude 124° and 129°, I'll never know for sure how long it lasts. I suspect it could be as short as four hours, though it could possibly be three times longer than that!

  (Postscript - I posted the photo from 8:34 UT Tuesday September 1 on the Facebook page Telescope Addicts - Astronomy and Astrophotography Community on Saturday, September 5 and asked if any other group members had ever seen or photographed what I've been calling the "Mare Crisium Sunset Ray." One reply that I received was from Rick Scott in Arizona. He seemed to think that this was the famous "false arch" along Mare Crisium; where the shadows seemed to suggest a natural arch lies on the rim. This was later proven false. I've read about this in the past but I was never sure where, exactly, this feature was located. He may well be right!)