The Thanksgiving Evening Fog Battle - I Lost!

  Thanksgiving day was unseasonably mild. We started off with cloudy skies and light fog in the air but by afternoon skies started to clear and Indianapolis had its first sunshine in six days. It was still clear at sunset but there was a mist in the air. Persistent cloud cover all these days hadn't given the ground a chance to dry out from heavy rain earlier in the week, and as skies cleared and temperatures dropped, light fog started to form. Still, since this was the first clear night in a long time, I decided to try to get out and observe. It turned out to be a battle with fog, and fog won. 

  My target tonight was the Eclipsing Binary star SS Ceti. I get on "EB (eclipsing binary) kicks" every now and then. These are double stars in close orbits with one another, and the plane of the orbit lies in our line of sight, which means that from Earth one star often passes in front of or behind the other star. These stars lie too close together to be seen as two separate stars in a telescope. However, what we can see is that the brighter star drops in brightness and then brightens back up again, usually in a matter of hours, as the dimmer star eclipses or passes in front of it. SS Ceti does a five hour dimming-and-brightening every three days (2.973976 days to be exact) and it was predicted to eclipse at 12:30 AM Friday morning our time. The star was expected to start getting dim around 10:00 PM Thursday night. 

  I almost called off observing to begin with because of the light fog in the air, but skies were clear so I hauled out the telescope and started observing. Even though it was very starry above my head, the horizons seemed to be lit up by the low-lying fog. The temperature was about 40 degrees F and the humidity was something like 90%. I guess I knew this would be a losing battle, but I was hoping there was enough of a steady light breeze to keep the telescope's corrector lens and my eyepieces from fogging up too much. 

  It was going well at first. I saw SS Ceti drop from 10.6 magnitude at 10:34 PM to 10.9 magnitude by 11:08 PM. It took a big drop from there to 11.2 magnitude by 11:06 PM. I jotted down my estimates and times, but dew was already forming all over the dew cap and tube. The finder scope was also fogging up. The mist suspended in the air was starting to make my clear sky with all of those blazing winter stars start to look murky, and I had the sinking feeling that I wasn't going to be able to do much more observing. By 11:45 PM. SS Ceti was getting hard to see because it was so faint, but even the easy-to-see stars around it were starting to look dim. I looked into the front of the telescope and it was clear that the big lens was starting to fog up. I had to give up on watching the rest of the SS Ceti eclipse.

  I wanted to make one useful observation tonight, so I went back inside and grabbed my chart for UX Orionis, since this star has been very active all month. However, by the time I was back outside the optics on the telescope had reached the saturation point. The front lens was totally fogged over and nothing could be seen through the scope at all. I had to admit defeat and call it a night without making one useful variable star estimate worth reporting to the AAVSO. I couldn't even really report the estimates I made of SS Ceti as it fell in brightness, because what's really valuable about an eclipsing binary star is an estimated time of minimum brightness, and I couldn't get that without catching it on the recovery after 12:30 AM. 

  You can't win 'em all. I can observe under a lot of bad conditions, but 90% humidity isn't one of them. All I could do was hope for better conditions the next night. There will be other chances to observe SS Ceti or some other EB star, and YSO stars like UX Orionis.

AM August 26th - V594 Cassiopeiae dimming event!

  Last night I had some of the clearest skies all summer and made 14 variable star estimates. One star I've been watching since last summer is V594 Cassiopeiae. It's a YSO (Young Stellar Object) just off to the side of a nice little star cluster called NGC 225 in Cassiopeia. All the time I've set the telescope on it, it hasn't done much. I've seen it as bright as 10.3 magnitude and as dim as 10.5 magnitude, so I couldn't call it an exciting target. Well, last night I finally saw a dimming event down to 10.8 magnitude. It isn't much, but it's the most activity I've seen. YSO stars are my favorite because they are unpredictable and under-observed. They're thought to be still condensing out of nebulae and surrounded by gas and dust. So last night what probably happened was a thick part of the gas and dust shell orbited into a spot between Earth and the star, and caused the dimming.

PM Sat. July 16 - Satellite Observing

  I've had a few good observing nights in June and so far in July, and made about 20 more variable star estimates. I haven't posted these to the site yet but may soon. 

  Yesterday evening (Saturday July 16) was clear at sunset but by the end of dusk clouds were starting to move in from the northwest. The clouds and the fact that there would be bright moonlight all night (the Moon was rising and 2 nights since Full Moon) made it not worth setting up the telescope, but I decided to get out the 7X35 binoculars, grab a patio chair, and watch for artificial satellites passing overhead. When I'd spot one by eye I'd follow it through the binoculars, jot down the time and position, and look up which satellite I saw online later when I was back inside. There was a flurry of activity between 10:55 PM - 11:10 PM where I saw 5 satellites, and I think I've identified them all this morning. Here's a summary:

  10:55 PM - Cosmos 2228 (#22286) (1992 - 094A) I spotted this one as a 3.0 magnitude steady object as it passed through the constellation Hercules into Draco, nearly overhead and heading north. The websites I researched gave it an orbit of 602 x 635 kilometers, inclination 82.5 degrees, and an orbital period of 97.07 minutes. It was launched December 26, 1992 by the Russians. 

  10:59 PM - Cosmos 1980 Rocket (#19650) (1988-102B) This was also steady in brightness, about 3.5 magnitude or brighter. I saw it pass through the constellation Lyra heading south to north. It has an orbit of 829 x 852 kilometers, inclination of 71.0 degrees, and a period of about 101.7 minutes. This was launched on November 24, 1988 by the Russians. Whenever I look at spent rockets in orbit I try to see if the magnitude brightens and dims to see if the rocket is tumbling in space, but this one either isn't tumbling or I was seeing it at the wrong angle.

  10:59 PM - Iridium 46 (#24905) (1997-043C) This was passing through Lyra at the same time as the Cosmos 1980 Rocket just mentioned, but it was going the opposite direction; from north to south. It was fainter at a steady 5.5 - 6.0 magnitude and faster, which showed it was in a lower orbit than the brighter satellite. It has an orbit of 776 x 779.4 kilometers, inclination of 86.4 degrees, and a period of about 100.4 minutes. It was launched August 21, 1997 by the USA. These satellites have super-reflective panels on them and are known to catch sunlight and flare up in brightness as seen from the ground below, but this one wasn't at the right angle to show a flare.

  11:06 PM - Thor Agena Rocket (#733) (1964-002A). This was bright and steady at about 2.5 - 3.0 magnitude. I saw it passing nearly overhead from Hercules to Draco heading north. It has an orbit of 762 x 812 kilometers, inclination 99.0 degrees, and a period of about 100.6 minutes. This is a super old rocket body from a launch on January 19, 1964, and it's still in orbit! It's a spent Agena rocket launched by the USA. Apparently it either isn't tumbling in orbit or I was seeing it at the wrong angle. After so many years since launch, if it had rotation in the past it probably stabilized a long time ago. 

  11:09 PM - I spotted a flash of light about 3.0 magnitude near Corona Borealis, high in the Northwest. When I trained the binoculars to that spot, I saw a faint object about 6.0 magnitude speeding off to the north, and while I was looking at it there was another brief flash where it brightened again to 3.0 magnitude. It faded again and disappeared into the trees to my north. I spent a lot of time using Calsky.com to try to find out what this one was, and the best match I have is this - USA 3 / Farrah 5 / KH 9-19 Elint (it seems to have at least 3 names) (#15071) (1984-065C). This is an aging US military satellite launched June 26, 1984. The orbit is 619 x 639 kilometers, inclination 95.9 degrees, period of about 97 minutes. I'm pretty sure this is a match and it's obviously tumbling. I'm going to find other pass predictions for this and try to get another look at it to know for sure if this ID is correct. I found out that this is a regular target for the Belgian Working Group of amateurs; known internationally for observing rotating satellites and rockets to determine how the rate of rotation changes over time. This was another reason I was pretty sure my ID was right.

  That was all the observing done tonight. Altocumulus bands moved in overhead and the moonlight was also an issue. It was also getting hazier as the night went on. Indianapolis is part of the newest big heat wave that's supposed to move in for the next week.

PM Sun. June 5th - AM Mon. June 6th Observing Notes 2

  (Catch-Up Notes) - After doing some lunar observing and taking photos through the eyepiece I left the telescope outside, and the dew caught up to it. By the time I went out to try to do some variable star work the big corrector lens in the front of the tube was fogged over. I had no choice but to take it inside and let it un-fog for a few hours. I didn't get it back outside until after midnight. It was still mostly clear but a little hazy. At zenith I could only see stars down to 4.3 magnitude and the limit through the telescope was 13.2 magnitude at best. I was outside between 1:35 AM - 2:40 AM and was able to make 5 variable star estimates before calling it a night. All of the stars I observed were YSO types. A couple of Bullfrogs were crooning away at a pond a few blocks away from us. Here are the estimates made tonight:

  1:52 AM (5:52 UT June 6) - VSX J182726.0-043447 was 11.5 magnitude. This is the star I call "Skiff's Star" for short, in the constellation Scutum. It seemed to be just barely dimmer than the 11.4 star nearby but much brighter than the nearby 12.0 star. I think this YSO dimmed just a little since I looked at it 2 nights before but this is iffy!

  2:04 AM (6:04 UT June 6) - WW Vulpeculae was 10.5 magnitude. It looks like this YSO brightened just a little since last week. I still haven't caught it taking a rapid plunge-and-recovery in brightness in two years of observing it; something it's known to do rarely. 

  2:16 AM (6:16 UT June 6) - SV Cephei was 10.6 magnitude. This is my first look at this YSO since observing it regularly last summer. Like the others, I still haven't caught a big dimming episode yet. 

  2:26 AM (6:26 UT June 6) - BO Cephei was 11.7 magnitude. This was another star I observed regularly all last summer. Mike Poxon suggested it to me then, but this YSO hasn't seemed to vary much yet. I did catch it dimmed to 12.0 magnitude early last September. 

   2:37 AM (6:37 UT June 6) - YZ Cephei was 11.5 magnitude. I observed this YSO regularly last summer also, and it shows a lot of small, quick changes in brightness. This was my first look at it this year.

PM Sun. June 5th - AM Mon. June 6th, 2011 Observing Notes 1

  (Catch-Up Notes) This night started out clear with a little haze. The temperature was in the high 70's F at the start of the night and calm winds were letting the humidity build up. The Moon was a thin Waxing Crescent about 4.2 days past New Moon. I did some lunar observing through the eyepiece and then tried to take some photos of it in my usual primitive way; holding my little Nikon Coolpix digital camera up to the eyepiece and hoping that some of the shots I took caught the image in focus while the air was steady.

  This photo probably turned out the best. It was taken at 10:03PM June 5 (2:03 UT June 6). The sunrise line on the Moon was at about 34.03 degrees E. North is down and south is up. The most obvious of the lunar "seas" are Mare Fecunditatis top and near the center, and the smaller, oval-looking Mare Crisium closer to the limb and a little below the center. The small craters in Mare Crisium still looked like dark spots because their floors were in shadow. The pair of big craters near the bottom of the picture are Atlas to the left and Hercules to the right. Near the top of the crescent the lunar highlands are really showy with all the craters and plateaus casting shadows on each other.

AAVSO - YSO Section

  I'll catch up and post some observations I made last week soon. The big news today is that the AAVSO's YSO section is up and running, and looks great! Mike Poxon emailed the link to me today. It has tons of centralized information and charts about these fascinating, active, and under-observed stars! Here's the link:

  http://www.starman.co.uk/ysosection/

YSO's (Young Stellar Objects)

  In my posts I often refer to "YSO stars" so I thought it might be good to give a little background information about them. 

  YSO stands for "Young Stellar Object." The long-standing theory is that these are stars that are still condensing from dust and gas, and by astronomical standards they are very young; on the order of just millions of years old instead of billions of years old like our Sun. Classifying them is difficult because they come in all sizes and types. The one thing they have in common is that they usually show a lot of unpredictable brightness changes, for a lot of different reasons. Since these stars are surrounded by gas and dust, they often fade quickly in brightness and recover because the ring of dust is "clumpy" and a thick patch of dust orbiting the star might float in between our line of sight and the star. Also, if a lot of gas and dust falls into the star, this can make it suddenly get brighter as the new material ignites on the surface.

  I've looked at a couple of YSO stars for years. Just after high school, one of the stars I used to report to the AAVSO (American Association of Variable Star Observers) was called T Tauri. I also made estimates for some of the interesting stars buried in the glow of the Orion Nebula. But most of the variable stars I observed and reported to the AAVSO were long-term variables like Mira stars and Semi-Regulars. I still observe these, but my interest focused on YSO observing about a year ago. For the last decade, there have been several automatic sky surveys created. These are robotic telescopes that image huge chunks of the sky every few days and automatically record star brightness. Though the all-sky automatic surveys are a boon for science, I was starting to get the feeling that observing long-period variable stars by eye was getting obsolete because of them. I wanted to start an observing program where I could still provide valuable data. 

  In the spring of 2010, I started to realize that YSO stars weren't being studied by very many people, and that they showed brightness changes that were so fast that a lot of the automatic sky surveys missed them. I started emailing around asking if anyone observed them regularly, and this was how I struck up a pen-pal relationship via email with Mike Poxon from Norwich, England. Mike had been observing these kinds of stars for years and confirmed my suspicions; that few amateur astronomers looked at them regularly, that they were getting increasing attention from professional astronomers, and that they showed a lot of wild short-term dimming and "flickering" that was too fast for the automated surveys to catch! Mike kindly provided me with lists of Young Stellar Object targets in range of my telescope and also with charts that showed these variables and comparison stars to estimate their brightness by. He continues to serve as my unofficial "mentor" when it comes to gathering data about these stars and provides prompt answers to my stupid questions about observing them. For this I am eternally grateful! 

  Recently, Mike Poxon emailed me to let me know that the AAVSO was going to start a YSO section and forum on their website, and that he would be hosting it. I hope to be able to help him spread interest about these under-studied variable stars, and also hope to keep adding more of them to my list and making a real contribution of data about their behavior.