There has not been weather like this in Missouri for at least 5+ years! According to weather records it was 2011 the last time we had any weather like this. Actually it seems that the 90’s were probably the last time we really had this type of weather pattern. School canceled, churches and businesses closed, these are the norm for this winter. In 2018 we barely even had snow at all!
One of the first things I noted upon moving from New Mexico to Missouri was the lack of clear skies! In New Mexico opening up the telescope every night for 2 straight weeks was not unusual. Opening up 2 nights in a row is very unusual here in Missouri. You make an adjustment on the telescope and it may be 2 weeks later before you get to try it out!
Since October there have only been a handful of clear nights and many of those those saw significant cloud cover by night’s end. The pattern has been ice and snow on Wednesday night with ice and snow on Sunday as well. One storm rolls out and a few hours later another storm moves in, with lots of high clouds in the hours between.
To add to the issue is the effect of all of this weather. My 2 telescopes are covered by heavy, weather resistant, tarps. Surprisingly enough, they work well. However, I had to cut short the last actual telescope session. It turns out the wind on the tarp loosened a knob and knocked the scope out of polar alignment. We did have a clear night at 7 degrees with a 25 mph wind but opening the telescope and polar aligning was not high on my list!
I also found that my cables get too stiff and hinder tracking when the temperature goes below 10 degrees. My current cameras are parallel port CCDs that use a heavy, stiff cable. This is enough to hinder tracking especially when the wind blows. In fact when my german equatorial mount would track, the power cable got so stiff that it would unplug itself. Obviously this required much more thought in routeing the cabling! None of this includes the ground heave during cold weather knocks the scopes out of alignment!
If these cold weather issues had ever confronted me before it would be easier to deal with them. A heat tape wrapped around the parallel cable is on the summer agenda of telescopic fix ups. Redoing the tripod foundations to minimize ground heave will also be a warm weather project. Hopefully getting some more clear skies will also be helpful!
Have you ever worked on a problem and gone backwards? You have an Ah-Ha moment where you know that you have the problem solved and then when you implement the solution it’s worse than it was before? Well that has been my experience with Temple 28, The Celestron 11″ CPC.
In earlier articles you find out about the struggles with a welded, non-adjustable wedge, loose gears and balance issues. Each solution should have led to a better working telescope but it didn’t. In fact Right before Christmas 2018, I just gave up in frustration on this scope, set up my AR102 refractor on the Sirius mount and began using it. Temple 10, the AR102 and Sirius combination, works really well! Since then I have obtained data on 2 close binary stars that no one has recorded since the original survey was done. At least I feel like I have accomplished something.
After much thought and research we finally had a day above freezing so I went out and began to work on Temple 28 again. Looking at online images, I noticed that all the images of the worm gear assembly differed from mine. There is a backlash adjustment screw with a spring on it that is easily observable in the online images. In everyone else’s pictures the spring was at least 1/4 of the way up the shaft, with several being compressed to 1/2. The springs on Temple 28 were fully extended and rested against the spring stop.
So I pulled off the RA cover and began to adjust the spring. It is pretty easy to adjust the spring if you remove the 2 small screws that hold the flexible coupling to the worm gear and swing the motor out of the way. However, I did not want to introduce that level of change. When problem solving, it is often best to only change one thing at a time. So adjusting just the spring was the best way to proceed at this point.
After adjusting the spring about 1/4 of the way up the adjustment screw I loosened the screw slightly. This is to make sure that the worm does not bind on the gear. After testing the motor I then did the same thing to the Dec axis. This was more of a challenge since it is in an awkward place to adjust.
After removing the the SBIG ST-8E, then putting it onto Temple 10, I needed a heavy camera to counterbalance Temple 28. I dug out my old SBIG ST-7E. This camera is an exact duplicate to the ST-8E but with a smaller chip. The ST-7E also does not have the SBIG CFW-8 filter wheel installed…since I can’t find the actual filter wheel for it!
Balance…always an interesting experience, in life and on a scope! When Temple 28 was first re-worked the tube balance point was moved to allow a heavy SBIG camera to be used. This means that what other people do on their CPC’s is not workable on Temple 28! Eventually, after much work I put two flat weights on the nose of the scope, the bottom 2.5 pound weight half way down the tube and strapped it all on tightly with hose clamps. Hose Clamps? Well they are cheaper and work just as well as 80-200 dollar rings or balance bars!
Well, the proof of the pudding is in the eating! So how did this newly adjusted system work out? Better, but not great! There was star trailing on about half of the images. For the type of photometry that I do it would probably still work in most instances but it is annoying none the less. In all fairness, when using the internal guiding chip, any fog, high cirrus clouds, corrector dew or frosting easily throws off the tracking. The conditions for this latest test were bad! High clouds, heavy dew on the corrector and forming fog in the sky. The a dew heater on the scope actually works fairly well. The presence of dew anyway says a lot about bad atmospheric conditions. So this test needs to be repeated when the conditions are better! In Missouri however, especially this year, any clear night, needs to be utilized regardless of conditions.
So what is the next step? Well the first thing is to find the filter wheel! I put it in a box during our move to Missouri where I could find it and haven’t located it since! This would bring the weight of the camera to match the ST-8E and facilitate an easy camera swap. It also makes doing photometry practical since the results are better if you use the right filters.
Second, is to take the RA worm assembly completely off, clean and polish the worm and gears, then re-adjust the whole thing. You can do small adjustments with the backlash adjustment screw but the large adjustments are made by moving the entire assembly, then tightening down 2 screws. When you read the posts about this whole saga, it becomes apparent that this should have been done on day 1! Quoting from the movie contact ” This is the way it’s been done for billions of years. Small moves, Ellie. Small moves.”
For the last 20 years or so I have been very interested in doing what is called Citizen Science. For me this entails measuring the brightness of variable stars and building what is called a light curve from that data. The light curve often shows what type of variable star you are observing. There are some examples of a light curve later on in this blog. My favorite targets are binary stars that are so close that their atmospheres touch and they revolve around each other in less than a day!
The American Association of Variable Star Observers has a database of variable stars called VSX. Some of the stars found on VSX have hundreds or thousands of observations over many years but the vast majority of stars have few or no observations. Many of the stars on VSX were found by professional or amateur surveys and have not been observed since. These little observed stars of close binary systems are what I enjoy the observing the most.
Each studied variable star in the VSX database should have a AAVSO Unique Identifier or AUID. Many of the stars in the VSX system don’t even have an AUID assigned to them yet. This is the easiest way to find stars that need observation is to look and see if an AUID has been assigned. If not, any AAVSO member can ask for a number to be assigned.
Last week I had the opportunity to image ZZ Aur, a close binary with around a 14 hour period. One of the reasons these types of stars are fun to image is the fact that they actually show pronounced changes in the 6-7 hours that you observe them. Some stars called LPV or Long Period Variables can take more than a year to change and this means that there is little change in brightness from month to month. So close variables are pretty exciting!
The above image shows the light curve of ZZ Aur. There were 97 images taken over an approximate 6 hour period. Each green square represents one image of ZZ Aur.
The equipment used to image ZZ Aur is pretty modest by most standards. The most important piece of equipment for imaging is the mount. A number of years ago I was able to purchase a used Orion Sirius mount for 450 dollars. I swapped out the tripod with 1.5″ tubular legs for a tripod with 2″ tubular legs. This probably increased the payload capacity from 30 to 35 pounds. The mount did not come with a Hand Control unit but it did come with a cable that enabled a computer to drive the mount. This is done with an EQDIRECT cable and EQASCOM software.
The telescope is a 102 mm (lens diameter) refractor. This telescope is an Explore Scientific brand called AR102. AR is short for a 2 lens doublet objective lens or an Achromat. When the scope was purchased several years ago it was around 300 hundred dollars on sale. The AR102 turns out to be just about perfect for imaging using a photometric filter. This is because the filter only passes a small wavelength of light which negates the effect of chromatic aberration or CA. CA is caused when the violet or blue light does not come to the same focus as the green and red light. Purple Haze is often seen around bright objects or stars in an achromat.
The camera is a 15 year old Santa Barbara Instrument Group (SBIG) ST-8E. This medium format camera uses an ultra slow parallel port cable to upload images. The average upload time is 67 seconds! This creates unique issues but then it is why the camera sells so cheap on the used market. It also has an effective cooling system that keeps the temperature steady. Keeping the CCD chip cold reduces the amount of noise or static in the image and this is important for getting accurate data in your images. I bought this camera used a little over a year ago for 250 dollars.
The SBIG ST-8E has a 5 filter wheel attached to it. The filters in it are photometric. These filters only pass a small wavelength of light in each color area. For example the g filter is equivalent to the green part of the spectrum. The r is red, the b blue and i infrared. With these Sloan photometric filters and the camera you can precisely measure the light of a variable star. The filters came with another camera that I got on another telescope I purchased.
One of the other pluses of this modest system is the wide field of view. In fact the area seen in one image is twice the size of the full moon which is huge in imaging terms. With this much field of view it allows for wide views that often include other variable stars in the same field. You also need stars with known magnitudes to compare the variables with. These are called comp stars. A wide FOV (field of view) makes finding suitable comp stars much easier as well.
One of the pluses of a wide field is other variables in the field of view. Near ZZ Aur is a variable called V0620 Aur. Turns out this variable had never been imaged since the initial survey. It is a great feeling to see that your observations are the first ones done on a star! V0620 Aur is also a close binary with a similar period.
Overall with a modest investment of 1000 dollars over a several year period I am doing actual science! This is something I have wanted to do for many years but never thought would be possible for the poor amateur like me! If you have an interest, even if you don’t have binoculars or a telescope, you can still do science! So contact the AAVSO at https://aavso.org/
Sometimes you have to go small if you want to go big! For a number of years I have been using 6″ to 11″ telescopes, most from F/8 to F/6.3. These provide a fairly detailed view but with a smaller field of view. A few weeks ago I decided to move my SBIG ST-8E camera to the AR102 refractor and Sirius mount. The results with this small refractor really go big!
The AR102 is an achromatic refractor from Explore Scientific. It was purchased several years ago from Highpoint Scientific. The original intention was to use this as a grab and go telescope but it worked so well as an imaging scope that is pretty much all it has been used for in recent years. Chromatic aberration is not a big issue when you use photometric filters. The only real issue is that you have to refocus each filter. However, you eliminate the blobs around bright stars by using filters. This type of telescope would also work well for RGB filters as well. An ED or APO scope is needed if you want to use a one shot color camera. You can make a poor man’s ED scope by using a Minus V filter when you image with a color camera. It doesn’t eliminate the CA but it brings it to a level you can often eliminate with processing.
One of the real pluses of a telescope and camera combination like this is field of view. The combination of medium sized ccd chip and short focal ratio give a field of view of approx 72’x 42′. Compared to the FOV that many of us had with our first cameras this is huge! So if you want to go big (FOV) you gotta go small (Focal Ratio and Focal Length).
The Sirius mount was purchased used, hypertuned by a friend and then put on an Atlas Tripod. The original Sirius tripod uses 1.5″ legs and the Atlas uses 2″ legs. This probably adds about 5 lbs to the amount of weight the Sirius can carry. My Celestron AR152, F/8 refractor actually works quite well on this mount and you can even add the SBIG ST-8E camera and it does not overload the mount and impair the mounts tracking. There was no hand control with the telescope when I got it but it has been used with EQMOD and EQASCOM. These programs work well.
So what can it do! Here are some images from the AR102, Sirius and ST-8E combination!
Sometimes you have to go small if you want to go big!
In the fall of 2014 a friend of mine told me he was getting out of astronomy. At the time Temple 20 (8″ Meade LX200) was taking automated data for a group in Europe at his observatory. He wanted me to come and get my scope. Upon arriving he offered to sell me a Meade 14″ or a Celestron 11″ CPC for pennies on the dollar. After thinking about it for a moment I chose the 11″ knowing that I just could not physically handle a 14″. My friend dubbed the scope Temple 28 since it was a twin of Wright 28 which at one time was part of the AAVSO telescope system. The naming system was the last name of the owner and a telescope number. Never did figure out how they came up with the number!
After 2 years in storage the telescope was setup in Espanola New Mexico in a roll off shelter. It survived the great SBIG fire when my ST-2000 camera caught fire, along with several local windstorms. During this time in northern New Mexico it imaged, but not well!
In the Spring of 2017 we moved to Missouri. Temple 28 was put in our backyard on a semi permanent mount. Though the site is light polluted it borders on a historic graveyard with limited lights and night time access. Not ideal but workable.
If you have followed the blogs on this site you will have read about the struggles to get this telescope up and running. The first big issue was the wedge. We are around 40 degrees north and the wedge was built for 33 degrees south. The wedge that came with the scope had been welded out of metal plates. You had to adjust the whole scope physically, turning the mount and tilting the legs. This is not a recipe for good polar alignment. So a Celestron Super wedge was obtained.
The next issue was weather. The first year here we only had a few clear nights all year long. It was almost impossible to make an adjustment then be able to test it in a timely fashion. The weather in 2018 has been a bit more amenable.
Balance was the next challenge. A weight system was constructed to balance the scope but I found out I was doing the balancing wrong! To balance a SC you tilt it vertically, balance it, tilt it horizontally, balance it, then finish the balancing by swinging it from side to side. The balance was achieved on Temple 28 pretty easily but there were still problems with tracking, especially in RA. I had used a medium sized C clamp attached to the west side handle to balance out the scope. After much testing it turns out that it was slightly too heavy. Your east side should be slightly heavier than your west side and though the scope appeared balanced it was still slightly off. It has now been replaced with some lighter weights attached to the west side. This has reduced the tracking errors with auto-guiding to less than 1 pixel. Though not the gold standard of auto-guiding it is adequate for the science imaging that I do.
After much trial and error the telescope will now plate solve. Turns out that the Celestron 6.3 focal reducer is not exactly 6.3. I actually prefer plate solving in CCDSoft and TheSky6 Pro but it is really sensitive to settings. So after finally achieving a solid plate solve in Maxim, I then took the plate scale and plugged it into CCDSoft, then played with the settings until it worked. It will now plate solve in either program.
For years I have used CCDCommander as a control program. This adequately controls all functions of imaging and allows the telescope to be used remotely. In the near future I will be trying Sequence Generator Pro to automate the imaging. This program allows you to use PHD guiding as well as several other features not included in CCDCommander.
Over all it seems Temple 28 is finally ready to do nightly work. Measuring the light curves of over-contact binary stars is something that I enjoy doing. There are thousands of stars listed in VSX (Variable Star Index on the AAVSO web page) as variable that have no measurements done on them besides the initial survey, which may or may not be accurate. There is a great deal of satisfaction to do measurements on these stars and know you are contributing to real science.
Several years ago my beloved Santa Barbara Instrument Group ST-2000 died a horrible death. Somehow the power supply melted a couple of chips. This included evidence of an actual flame inside the camera. Still not sure why or how it happened but the wonderful ST-2000 was no more!
I reached out to the American Association of Variable Star Observers, an organization I had have belonged to since the mid 1990’s. In an Email to Arne Henden (the former head of the AAVSO, now retired) I asked if there was a camera that I might borrow to replace the ST-2000. Several weeks later it showed up at my doorstep!
When I opened the package I gazed with surprise at the ST-402 Photometric camera. That is not what was so surprising! It turns out that this was a camera I had to send back to the AAVSO a few years before because a friend of mine decided to get out of astronomy and the camera was mounted on my LX200. The camera and telescope were at 9,000 feet in Southern New Mexico and were providing data on Blazkho stars to a group in Europe. My friend quit astronomy in a big huff and the camera had to be returned to the AAVSO as part of the heated (on his part) separation. When my friend quit astronomy he sold me his 11″ Celestron CPC and the ST-2000 so I did not miss the ST-402 camera on the LX200.
How odd that several years later the camera should resurface as a backup to my now departed 2000. Though it does not have the bigger chip and internal autoguider like the 2000 it did come with BVIC filters internally mounted with the camera. It uploads fast and was very reliable. That is until we moved to Missouri due to a job change and the silly thing seemed to stop working correctly.
I set up my Sirius Mount, AR102 telescope and used the ST-402 as the imager. Everything worked quite well except the 402! The images would sometimes come out ok and sometimes it was obvious that the shutter was only half open. The shutter has the 4 filters mounted on it and when the shutter closes it is supposed to go between the filters. When the shutter opens the filter moves over the chip. This was not happening reliably.
I put the camera on the shelf since I was busy trying to get my 11″ CPC to actually work! I had also purchased a used SBIG ST-8E parallel port camera for 225 dollars. This has the same size main chip as the 2000 but uses parallel port instead of a USB port. The internal guide chip is smaller than the 2000 but still workable.
Today I finally got around to checking out the ST-402 issues. I had tried to just tape the V filter over the chip but would get weird results. It worked but you would get strange looking images. I guess there is a reason to have a shutter!
In looking up issues with this camera online a couple of other people had had similar issues. The solution was to download the latest USB driver from the Diffraction Limited legacy support site. So I did that. However, there was one step that I neglected because I was in a hurry. All of my laptops used for astronomy had the old USB and Parallel port drivers on them. My thought was that those drivers would be a generic SBIG run all. So on the laptop I use for this camera I just ran the new drivers over the old drivers and figured that would do it. Ran Maxim DL 5 and still had the same issue, same with CCDSoft.
This afternoon I uninstalled the old SBIG driver checker and reinstalled the new driver checker. Booted up CCDSoft (still like it better than Maxim, but it is a personal preference issue) and it still didn’t work. I went through all of the filters and after hitting the B filter it worked fine and continued to work fine. Clicked out of CCDSoft, unhooked the power from the camera, then reversed the steps. As long as you start the camera with the b filter in it’s first image the rest work fine. If you don’t it will give you random filters until you go to the B filter, then it works ok after that. Very strange!
So after about 5 reboots this technique has been added to the start up procedure. Maxim DL5 still won’t work with this camera. I suspect that the “legacy” drivers that you have to load for Maxim to use parallel port cameras are not new enough to run the ST-402. Will try uninstalling those drivers in the near future and see if that solves it. Using this camera on an F6.5 focal ratio refractor gives a very wide field of view. Here are some more examples of how well it works.
A friend got so disgusted with his Celestron Nightscape Camera and Celestron Tech Support that he sent me the camera and said good riddance! After emailing (no response) and finally calling, I found out Celestron no longer supports this camera so I began to troubleshoot. The issue was bright squiggly lines across all the images, plus the cooling fan no longer worked.
After taking the camera apart a couple of times it appeared that the fan wire had chaffed against the heat-sink and was shorting out. Everything worked normally if you disconnected the fan wire. So I have ordered another fan on Ebay and will try hooking it up as it originally was. If that doesn’t work then I will most likely rig up an external power supply to run it. I have found that using an adjustable power supply (Like the ones you can get at Walmart or other stores of it’s type with settings up to 12 volts) allow you better cooling control than reconnecting it to the 2 pin power supply on the bottom board. The 2 pin board only allows 3 speeds. With an adjustable supply you can have up 5 or 6. This was done this with a SBIG ST-7E fan and it worked very well until I got the right replacement fan.
These cameras are well engineered but use cheap parts for the fans, ports and connectors. Many problems listed online about Nightscapes include issues with the poor USB or Power connectors. The fan wire goes through a hot, sharp edged, heat-sink, so shorting out is not a big surprise. Just moving the camera around would could eventually lead to cutting the insulation. If I reconnect the fan to the internal power supply I will cover the part that goes through the heatsink with shrink tubing or another type of insulator which should have been done at the factory.
I am hoping to get a chance to try it out without using cooling as soon as weather and schedule cooperate. The trick of using it without cooling is to shoot darks at around the same temperature that you shoot the images and then subtract them. This will alleviate most of the dark current issues caused by heat. The AstroFX software provided free is supposed to do this quite well.
That also brings up another issue. When I called Tech support the only useful advice I got was to use the latest ASCOM driver. This is not the one you find when you go to the generic Celestron support page. You have to put in a Google search “Celestron Nightscape ASCOM driver download” and that will take you to their info page on the camera. Under Manuals and software you will find the latest driver! The other driver that comes with the AstroFX software does not work on Maxim DL5. After disconnecting the fan, re-installing the separate driver and setting it up on Maxim, it worked fine. So if you are having an issue try re-installing the ASCOM driver. The tech support guy also said to use high a quality USB cable. Kind of think that is somewhat intuitive!
Though I typically do Citizen Science type images it is fun to take some color images from time to time and this camera works pretty well for that sort of thing. There are thousands of colorful images online taken with this camera. Hopefully I can get this thing back on it’s feet again!
In today’s quest for dark matter, black holes and active galactic nuclei, small dwarf stars tend to get overlooked. The fact that small amateur telescopes can image a star seem to indicate there is little of interest remaining to the professional for study. Being able to study a star with a small aperture also does not lend itself to procuring today’s cutting edge equipment for sexy science. Since stars were extensively studied near the turn of the 20th century many scientists feel it is time to move on to the next great mystery, whatever that might be. In my warped thinking this seems to be a good place to start to look for something interesting. Especially with the sophisticated equipment available today.
The great observer E.E. Barnard discovered the high proper motion of V2500 Oph in 1916 after examining photographic plates from 1894 and 1916. At the time Barnard was a professor at the University of Chicago’s Yerkes Observatory in Williams Bay Wisconsin. Not only was he a very skilled astro-photographer but was also a very seasoned visual astronomer. In the late 1800’s and early 1900’s a good astronomer had to be good at the old visual/sketching observing as well as pushing the envelope with photographic observing.
Barnard’s Star is a M5 star. This means it is a cool red dwarf star and is easy to observe with a small telescope since it is only 6 light years away. A high proper motion star is one that seems to be moving very rapidly across the night sky. Since it is close and has a rapid velocity it moves 10.29″ across the sky every year. You can see how it has moved in the above image taken with Temple 28. Barnard’s Star is moving at the rate of 103 miles per second. This means that in 351 years this star will move 1 degree in the sky. Compared to other stars this is a Porsche among snails. There are other objects that are faster but none of them as close, so it’s velocity is readily noticed here on earth!
This high proper motion as well as it’s relative ease of imaging caused a great deal of controversy. Dr. Peter Van De Kamp an astronomer at Swarthmore College’s Sproul Observatory. Dr. Van De Kamp used the 24″ refractor to observe Barnard’s Star from 1937 until the early 1970’s. He found a “wobble” in the proper motion of the star that led him to conclude that the star had a large planet orbiting. Until his death in 1992 he tenaciously held onto the idea that he was the first exo-planet discoverer.
In 1973 astronomers George Gatewood of the Allegheny Observatory and Heinrich Eichhorn of the University of Florida, using data obtained with improved equipment on the 30-inch Thaw Refracting telescope, did not detect any planets but instead detected a change in the color-dependent image scale of the images obtained from the 24-inch refractor telescope at the Sproul Observatory used by Van de Kamp in his study. Astronomer John L. Hershey found that this anomaly apparently occurred each time the objective lens was removed, cleaned, and replaced. Hundreds more stars showed “wobbles” like Barnard’s Star’s when photographs before and after cleaning were compared – a virtual impossibility.
Since then there have been numerous attempts using modern techniques to discover exo-planets around Barnard’s Star without avail. Since this star is only 6 light years away finding a planet would be a boon for study. It is much easier to study a planetary system 6 light years away compared to one 60 light year’s away. The Red Dots (https://reddots.space/photometry-log-4-end-of-campaign/) has imaged Barnard’s star repeatedly looking for any kind of signal change that would signify a planetary transit. Other than the obvious that the M class star is very slightly variable (4%), no eureka moment can be found!
In one long time series ( 60 second exposure) of Barnard’s star from Temple 28, the star exhibited a really strange light curve. Turns out it was over exposed. It was way over exposed, which is a common error of those of us that tend to image much fainter stars than Barnard’s. Doing another long time series (15 second exposure) yielded similar variability to what the Red Dots Campaign found. My cadence for the images is pretty slow since it takes around 70 seconds to upload an image to the computer. Therefore it is hard to see the shape of the actual light curve. With my equipment all that I can really tell is that it is a micro variable that varies around 4%.
Next observing season I hope to image with the AR102 (Temple 10) and do a 20 second cadence instead of an 85 second cadence. This might reveal the actual shaped light curve so the nature of the variability can be determined.
Barnard’s Star is a star that still holds interest for Citizen Scientist and Professional alike!
Looking at Facebook Telescope Addict page you notice a trend in amateur astronomy. There are hundreds of terrific pictures of planets, galaxies and nebula, but very few images or comments on stars! Up until the 1950’s much of astronomical efforts had to do with stars, with a few notable exceptions. How hot they are, their precise positions, distance, color and composition led the thousands of scientific papers that poured from universities all over the country. Recently the Gaia data releases have brought some focus back to stars but it is just a small blip on some professional astronomers radar.
For those of us that started early in life to look through telescopes, we spent hours looking at the stars and never could get enough. Double stars, colored stars and groups of stars were all terrific targets for small kids with small scopes. The joy of just looking at the stars took us far. In our current day, quality cameras and equipment have moved us to imaging really cool nebular stuff and away from stars. These nebular objects were hard to photograph back in the days of film even with large telescopes. (See my comparison of the 200″ Palomar scope and an 8″ reflector here… http://templeresearchobservatory.com/palomar-vs-tro//). Virtually every professional observatory during that time had major studies of the stars going on. Where has the interest in the stars gone? Why don’t more amateurs and professionals alike spend time on these objects?
The common perception is that we know just about everything that we need to know about stars. Wow is that a misconception! In the fall of 2010 while imaging M 57 or the “Ring Nebula” with a 6″ refractor, I found myself wondering if the Blue White Dwarf star that forms the heart of the nebula was variable. As a freshman in college I remember looking through the 24″ refractor at Lowell Observatory after the public session. This was back when I was young, good looking, a college running back at a DIAA college and the telescope operator was a pretty coed! After looking at a few pretty objects the operator turned to M 57 in Lyra. Upon putting my eye to the scope a small purple star floating in a green ring of gas popped out and hit me in the face! It was beautiful! This is probably the time when Stars became Stars to me!
Though the behavior of white dwarfs was well known in some circles, few professionals or amateurs that I talked with had a clue whether it was variable. Burnham’s guide said it was variable by 1 magnitude and several catalogs listed it as variable but no one really knew. After contacting every professional astronomer I knew (and some I didn’t know) the common answer was “I don’t think so but why does it matter?” Arne Hendon of the AAVSO, Arlo Landolt of Louisiana State University and Rik Hill of the Catalina Sky Survey were the only ones who knew about the possibility of variability and encouraged me to study it.
Turns out it is variable! In fact most white dwarfs are variable! Howard Bond and Al Grauer in the 1970’s and 1980’s found numerous dwarfs that exhibited variability. The average variability is around 2% so it is hard to detect but definitely in range of many of today’s amateur telescopes. In a short run with the AAVSONET Wright 28 Telescope (11″ Celestron SC with a SBIG ST-7E camera) the variability followed the predicted amount of 2%. Using this data and some Kepler spacecraft observations for comparison in a poster at the Kepler Science Conference in 2011, it caused some surprise from many established scientists (though they also indicated that it was not all that important!). The majority of those that took time to look at the poster had no clue that white dwarfs were variable. The common question was “What mechanism would cause that?”
Some of the best guesses are sunspots, long term flares, gravity waves or shell fusion. Bond and Grauer found that some dwarfs actually had similar light curves to pulsating variables but on minute scales, not hours or days like larger stars. Since white dwarfs are made out of degenerate matter where a teaspoon of dwarf matter weighs a ton makes this unlikely. Around many dwarfs there are thin, 20 kilometers or less, shells of hydrogen or helium gas. So if the star is pulsating it is only pulsating in that thin gas envelope.
The most interesting possibility is gravity waves and the most likely. If you saw the movie “Interstellar” you will remember the giant wave that almost destroyed the ship and people…that’s a gravity wave. Imagine a wave of 100,000 K gas, 20 kilometers or more high, racing completely around the white dwarf in minutes! If that is not a cool picture I don’t know what is!
Two really interesting books about “boring” stars are “The Hundred Greatest Stars” by James B. Kaler and “The Brightest Stars: Discovering the Universe Through the Sky’s most Brilliant Stars” by Fred Schaaf. Both of these books are on the most interesting bright stars in the sky. A case in point is the strange star of Beta Lyra also called Sheliak. This is an easily seen naked eye star in Lyra. It is often used to help find M 57 but deserves a good look from time to time on your way to the Ring. The main star is a Blue Class B giant star with a Class B dwarf star 30 solar diameters away from it. They are so close together that gas is being sucked into the smaller dwarf star. Some of the mass flowing from the larger star to the smaller is lost to space and creating a tail behind the pair! Both of these books are filled with really interesting facts and stories about these brighter stars. Definitely worth a look in the book and in the sky as well!
So are the stars no longer Stars? Don’t think so! In fact with the increasing sophistication of equipment, smaller and smaller telescopes can turn out professional top quality data. As professional astronomy gear gets more and more expensive, it is falling to amateurs to continue much of the work that the observatories and universities used to do. Groups like the AAVSO and BAA are still viable and provide high quality Visual/Imaging data to researchers both professional and amateur. If you have an interest in actually doing science I would encourage you to go to https://aavso.org/observing-manuals and read the visual or CCD photometry manuals. These are free and point you toward where you can use all that expensive equipment, binoculars or even naked eye, to actually do science!
Next clear night take some time to look at and appreciate these bright jewels of the night sky. If you are an imager take some star pictures of the stars as well! Make the Stars, stars again!