When I drove home from Greensburg from about 1:30 AM - 2:15 AM the sky was clear. I didn't drive through any low fog banks anywhere. It was chilly but there wasn't any dew to speak of on the car. I came home and heated up dinner, and then started to take the telescope outside to the patio after 3:00 AM. It was plugged in with the dew cap on and I'd pointed it at the Lambda Orionis area before 3:30 AM.
I wore a hooded sweatshirt tonight. This was comfortable enough, but the dewy and chilly conditions started to get to me by the end of my second session outside.
This was the second time I'd had the telescope outside this week, and for the first time ever I had my voice recorder outside in place of a notebook. I used it to record variable star magnitudes as I made them, intending to type them into the Evernote App on my tablet. I think this might be a good, faster method of keeping my observing notes up to date from this point on. I'll see how it works.
It was a clear night with fairly still air. There may have been a light high fog, but my limiting naked eye magnitude was around 5.1 and the limiting telescope magnitude was about 13.1 or 13.2, so it was almost ideal from our back yard.
I DID see one small cloud band low to the west when I started observing just after 3:30 AM, but it never moved close to the southeastern sky where I was observing and I didn't see it or any other clouds after 4:00 AM. By the end of observing there was a pretty good amount of dew on the dew cap and telescope tube but the eyepieces remained dew-free.
At 4:00 AM the Temperature was 59°F, the Dew Point was 51°F, the Humidity was 75%, the Wind was North at 5 mph, and the Pressure was 30.21". By 5:00 AM the Temperature was 58°F, the Dew Point was 50°F, the Humidity was 75%, the Wind was from the Northeast at 5 mph, and the Pressure was still 30.21". I didn't feel any wind tonight; it just felt chilly and dewy.
Crickets were chirping away the whole time I was out there. They weren't as lively as they'd been during really warm and muggy nights just a few weeks ago, but their sound filled the air. I also heard the usual low rumble of traffic on I-65 and some neighborhood dogs barked. After 4:30 AM a lot of low jet aircraft started flying overhead. Otherwise it was a quiet night. I had no mosquito problem at all.
The chart below was obtained from the Freestarcharts.com website. I drew in the rough positions of the variables seen tonight on that chart (unfortunately, FM Orionis was a little off the top of it!). It also shows the brighter stars in Orion and the nebulae M-78, M-42, and M-43.
Session #1 - 3:32 AM - 4:30 AM (7:32 - 8:30 UT Sept. 26)
3:46 AM (7:46 UT) - I estimated FM Orionis at 11.2 magnitude. I used ASAS 050844+1022.3 (approximately 10.5 magnitude) and ASAS 050907+1037.6 (approximately 11.5 magnitude) as the comparison stars. I used Chart 13621ESD. The ratio was about 10.5 - 2/3 - FM Ori - 1/3 - 11.5. 78x power used. I was confident with the accuracy of this estimate. I star-hopped to this variable star from Lambda Orionis and it was fairly easy using a finder chart I'd printed from my Starry Nights Backyard planetarium program. This star is just five or six degrees west of Lambda. After making this estimate I carefully checked the field to make sure the magnitudes of the other stars seemed accurate, since I'd gotten them from the ASAS website just the previous night. I also used 102x power to do this. They seemed just fine. I also noted that the variable and all of the comparison stars fit into the 102x field of view (which is roughly 20 arc minutes), for future observing. This was my first ever look at this long-period eclipsing binary (type EA) and there are no estimates at all for it in the AAVSO database. The Lichtenknecker database has 20 visual estimates for it but no CCD estimates. The range is listed as 11.3 - 12.9 P magnitude and the period is a little over 22 days long. The next predicted eclipse will be centered around 16:45 UT September 28, or 12:45 PM this Sunday for me. The eclipse duration is about 37 hours, so if this prediction is right the eclipse would start around 7:00 PM on Saturday the 27th and end around 7:00 AM on Monday the 29th. The next predicted eclipse would happen October 20. This looks like an interesting star to keep following.
I pointed the telescope at the Orion's Belt stars next and used a finder chart I'd printed last autumn to star-hop to the area of M-78. I had a look at this nebula several times while I estimated the next three stars, it was a nice, fairly-bright glowing patch through the eyepiece with two dim stars shining within it. Then I made these estimates.
4:11 AM (8:11 UT) - I estimated GT Orionis as <12.5 magnitude. This was a true challenge! I tried like mad to make a positive estimate for this star, but I just couldn't do it. I barely saw anything where it was supposed to be even with 102x power, and after struggling to see the area under 203x power I thought I could glimpse it now and then along with the 12.8 comparison star, and thought maybe it was slightly brighter at 12.7 magnitude. This was the estimate I was originally going to give, but I had to be honest with myself and admit that I wasn't sure if I was looking at the right star (whether it was GT Ori or the 12.8 comparison star since I only rarely thought I was seeing them both). Since the faintest star I could consistently see was the one marked as 12.5, I had to settle for the "fainter than" estimate. I used Chart 13622LTK. This UXOR star must be having a deep fade!
4:22 AM (8:22 UT) - I estimated V351 Orionis as 8.6 magnitude. I used the 8.2 and 9.2 comparison stars on Chart 13622LSM. There's an 8.5 comparison star on this chart that I could have used, but since this one has a close companion star I didn't want to use it. This was a much much easier estimate to make than the previous one! V351 Ori seemed to be about halfway between these stars in brightness but slightly closer to the 8.2 star. 78x power used. This UXOR star is near the bright end of its magnitude range.
4:27 AM (8:27 UT) - I estimated V1380 Orionis at 9.9 magnitude. After a lot of scrutiny using both 78x and 102x power, I found it equal to ASAS 054657+0020.2 (approximately 9.9 magnitude). There were times when it looked slightly brighter or dimmer than it, but I settled for equal. It was definitely brighter than ASAS 054635+0036.9 (approximately 10.2 magnitude) and definitely dimmer than ASAS 054844+0023.9 (approximately 9.6 magnitude). I used Chart 12635AOB and I looked up the comparison magnitudes on the ASAS website last autumn. This eclipsing binary has a range listed as 9.6 - 10.0 V magnitude and a period of a little under 2.5 days. There are only 2 estimates for it in the AAVSO database from 2 different observers, one in 2008 at 9.9 mag. and one in 2002 at 9.7 mag. I made a few estimates of it last autumn, but as of tonight I still hadn't entered them into the AAVSO database. I plan to do that soon. The Lichtenknecker database doesn't have this star on its list at all. The next eclipse was predicted to happen at 7:30 UT Sept. 27, or 3:30 AM tomorrow (Saturday) morning. If it's clear I should definitely get a look at it. The eclipse duration is either unknown or not listed on the VSX site.
Session #2 - 4:40 AM - 5:10 AM (8:40 - 9:10 UT Sept. 26)
After a short break, where I went inside to get more charts, I went back to the telescope. Right when I started recording again, trying to make sure it was just as clear as it had been before (it was), I spotted a really bright meteor that streaked from just east of Capella and "the Kids" stars to north of Auriga. This happened around 4:41 AM (8:41 UT Sept. 26). It was brighter than Capella so I figured it was -1 magnitude, had a swift speed (around 4), and had a train that lasted for at least one second, and was yellowish in color. It wasn't a long-lasting meteor. From its speed and location, I was fairly sure it was a member of the Orionid Shower.
The telescope had been left set on the Orion Nebula M-42. I only had a brief look at this under 39x power, but it was beautiful as usual. Then I panned over to Iota Orionis and a little further south to make the next two estimates.
4:48 AM (8:48 UT) - I estimated V380 Orionis as 10.2 magnitude. I used the 9.8 NW and 10.5 NW comparison stars on Chart 13622LOK (D scale). 78x power was used. V380 Ori seemed to be right in between these two stars in brightness but slightly closer to the 10.5 star. I'm sure this estimate is accurate to +/- 0.01 magnitude. As always, the star looked "fuzzy" compared to the stars around it, since V380 Ori sits in the middle of the nebula NGC 1999.
4:52 AM (8:52 UT) - I estimated BF Orionis as 10.3 magnitude. I used the 9.9 and 10.5 E comparison stars on Chart 13622LOR (D scale). 78x power was used again. The ratio seemed to be about 9.9 - 2/3 - BF Ori - 1/3 - 10.5 to me. Once again I'm certain that this estimate was accurate to +/- 0.01 magnitude.
I then star-hopped from Beta Eridani to make the next two estimates.
4:58 AM (8:58 UT) - I estimated UX Orionis as 9.7 magnitude. I used the 9.5 and 10.2 comparison stars on Chart 12584ZJ (D scale). 78x power was used. It was slightly but definitely dimmer than the 9.5 star but much brighter than the 10.2. I'm sure this is accurate to +/- 0.01 magnitude again.
5:06 AM (9:06 UT) - I estimated FL Orionis as 10.9 magnitude. I used ASAS 050735-0244.0 (approximately 10.3 magnitude) and the 11.1 comparison stars on Chart 12585AUO (E scale). 102x power was used. This wasn't a really easy estimate to make since the 10.3 star sits between the variable and the 11.1 star, and it was very distracting! However, after a lot of looks and trying to stare below all three stars, I decided that FL Ori was slightly but definitely brighter than the 11.1 star and much dimmer than the 10.3 star. FL Orionis wasn't predicted to be in eclipse tonight, but I wanted to get a better idea of what its "normal" magnitude is visually. I'll probably estimate it every night whether it's in eclipse or not (more often during actual eclipses of course) since I don't think enough observers do this for eclipsing binary stars. Plus, it's also listed as a Delta Scuti type!
Although I was going to look at SAO 58521 again in M-37, like I did 3 nights ago, these 8 variable star estimates had taken longer than I thought (especially GT Orionis!) and I was getting very fatigued, so I decided to call it off and save this for another night. As I was packing up the telescope the Winter Stars were all over the eastern half of the sky and the Pleiades were nearly overhead. Sirius, Procyon, and the stars of Gemini were all well over the roof of our house and the neighbors' house to the south and Orion was sparkling well over the trees. I could also see the gleam of Jupiter hidden in the foliage of the tree across the street over our roof.
One Final Note - I went outside at 6:15 AM and I'm pretty sure there was a hint of dawn in the sky. I spotted Regulus just peeking over the roof of our house from the edge of the patio to the right of that tree across the street, and the top of the Sickle of Leo above that tree. This was my first Regulus / Leo sighting of the season. Jupiter by this time was gleaming pretty high over the roof between Gemini and Leo.
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