Bumps & Humps

One of the reasons that I chose to observe variable stars is that they represent the truly dynamic nature of our universe. So much of what we observe outside of our solar system tends to be very static. With the exception of a nova, the galaxies we see through our little eye pieces appear the same today as they did a thousand years ago and will be the same as they will appear a thousand, perhaps a million, years from now. It is really difficult to get an understanding of the true dynamic nature of our universe. Enter variable stars. Depending on the nature of variability, these stars can change in apparent brightness in days, or even hours. The subject of this week's blog is on light curves of a somewhat predictable class of variables called Mira's.

When I first started to observe Mira's, my assumption was that they would be fairly predictable and make nice sinusoidal curves when plotted. Well, I now know that I could not be more wrong. To illustrate this, I would like to present light curves of three Mira type variables in Cassiopeia,  W, T and S. The light curves plot the apparent brightness of the star over time. The curves below are on a timescale of 1600 days. The date is the Julian calendar date. Today is the extreme right on the graphs. My personal observations are marked by the blue crosses.

Above is the light curve of W Cas. At first glance you can see quite clearly the sinusoidal oscillation, however, take a look at the minimums. Quite clearly there was one minimum that was noticeably deeper than the others.  

Now here is another Mira, T Cas. The odd thing here is that there appears to be a double maximum. Each time the star reaches its maximum and starts to fall off, there seems to be a rebound and the star brightens again before finally falling off to its minimum. Currently the star is about to enter its 2nd maximum stage. It will be interesting to see what my next estimate will be.

Lastly, here is S Cas. Initially it looks pretty "normal," but again there is something out of place. Look at the last rise to maximum. There appears to be a stall in the progress when the star reached 12th magnitude. This is called a "hump." The previous two cycles show evidence of this hump, but they are less pronounced and occur at a lower brightness than the last one. There is even evidence for a hump on the dimming side of the second cycle.  What will the next cycle look like?

So, there you have it. Three "predictable"  Mira's showing very unpredictable or unexpected behaviors on a time scale that we can witness.

Clear skies;
rw

New Year Resolutions

Every year, as the old year passes to the new, we are given an opportunity to reflect on our achievements of the old year and think about our goals for the new. We do this in the business world, with our personal lives and so why not with our hobbies?

First, let me reflect on 2010 a bit. 2010 was a renewal year for me and this hobby. The enabler for this renewal was the discovery a new dark site. Prior to 2010, most of my observations were done from my backyard. While this was extremely convenient, the recent influx of a couple of car dealerships and some lighted soccer fields into the area had made observing from my backyard a less than desirable activity. The new dark site is about a fifteen minute drive and gives great views to the East, South and West. The North is still washed out by the light dome of Houston, but it is tolerable.

2010 brought new vigor to my variable star observing program. I logged over 100 entries to the AAVSO data base. This was the first time that I achieved the "century" mark.

I attended two major star parties in 2010, the Texas Star Party and the Eldorado Star Party. The latter afforded me the chance the use my new Z10 Zhumell scope under ideal conditions. This is a wonderful instrument as it affords me the opportunity to see some really deep sky objects, as well as see more of my variables down to their minimums.

So now that brings me to 2011. As I look forward to this year, I think about some possible goals. Setting goals always has the effect of motivating me and provides me the chance to monitor my progress. (I guess my engineering degree permeates just about all aspects of my life!) So what do I want to achieve in this hobby over the next twelve months? Well, certainly at the top of the list would be the continued observation of my program variables. As I am becoming more efficient at observing these variables, it allows me to add more to my program. So, I think that adding a few more variables to my program would be in order, while still aiming for a 100+ observations over the year. I currently have 30 stars in my program. I think adding another 10 stars over the year would be achievable....but now to decide which ones!

A second priority would be to make more progress on the Herschel 400 list. I am currently about 17% complete on this list. I think that I could observe maybe another 100 objects on this list, and so, I am aiming for 42% complete by end of this new year. I would also like to do more sketching of these objects as well. Sketching is a wonderful way to observe as it forces you to take time and really observe the object in the eyepiece. As you spend more time at the eyepiece, more details come out and sketch provides you with a really nice record of these details.

And lastly, I want to do more sharing of my hobby through conduits such as this blog and my web site, rwAstronomy.com. This is a great cloudy night activity and brings me into contact with other amateurs.

So there you have it, my accomplishments for last year and my goals for this year. All that I need now is clear skies and spare time. Hopefully, these two variables will "align" for me in 2011.

Happy New Year and Clear Skies for 2011!

rw

Eldorado Tx. Star Party

The Eldorado Star Party was hosted by the Austin and San Antonio astronomy clubs. It is an annual event held at the X-Bar Ranch just south of Eldorado Tx. This year the event took place the first week of November.

The weather and skies were simply unbelievable! I had three very successful nights hunting for "faint fuzzies" with  my new Z10.

This was the first real challenge for the Z10. The scope easily pulled in galaxies down to 11th and 12th magnitudes. It is truly amazing what these light buckets can achieve.

The telescope observation list that the organizers provided was in a word "challenging." I was unsuccessful at completing the list, but by no means did this detract from the experience. I found lots of other objects on the H400 list to observe. I spent a lot of time in Cetus, observing and sketching. My sketches will be a subject of another post.

The facilities at the ranch, were a little on the "rustic" side. There were hot showers which were appreciated as the weather was a little on the cold side.  Potable water was also available. The ranch has very limited accommodations and so most attendees either camped or stayed off site. I chose to camp and to cook my own meals. This worked out well and I would do it again.

One of my favorite activities of any star party is to look for the "unusual" or "creative" examples from our hobby. Well here is the blue ribbon winner of this party. This is a 10" scope which has been adorned with gadgets and accouterments which enables the observer to be as productive as possible. The owner of the scope made the comment that his scope has "character" and I could not agree more.

Clear skies;

rw