Galaxy Trio in Cetus

Every once in a while I will see something through the eyepiece that just begs for more investigation. This happened one night in November when I was observing the Herschel objects in Cetus. I came across a field that held three galaxies, NGC 1035, 1042 and 1052. While having three  galaxies in a 1 degree field in a 10" scope does not seem all that unusual, the fact that these three galaxies all looked very different did intrigue me a little and I made a mental note to follow up and learn a little about each of these objects.

My first question was this just a chance alignment or are these galaxies "neighbors." Well to answer this, I went to the  NASA Extragalactic IPAC Data Base. This is a great resource for details on galaxies. In looking at the distances of the three galaxies we see that NGC 1035 and 1052 are 62 and 64 million light years distance while NGC 1042 is a mere 34 million light years away. So it would appear that NGC 1035 and 1052 are somewhat related as their separation is only about 2 million light years. This is similar to the separation between our own Milky Way galaxy and our close neighbor the Andromeda Galaxy.

The database says that NGC 1035 is a SAc normal spiral galaxy. Through the eyepiece, the galaxy appears to us as more edge on than face on.  It has a visual magnitude of 12.2 and is approximately 2 by 4 arc minutes in size. It has an even brightness along its major axis.
You can see from the UKSchmidt photograph to the right that there are beads of higher density stars clusters distributed along the spiral arms. This structure was not visible through the eyepiece at 75X.

NGC 1042 is a face on SABc barred spiral galaxy. It appeared as a soft circular patch in the eyepiece with relatively even brightness. I estimated the dimensions to be 3 by 3 arc minutes. The visible magnitude is 11.0.
The MW_Pal photograph to the left clearly shows the spiral arms and the barred center. These structures were not readily visible through the eyepiece.

NGC 1052 is an elliptical galaxy. Through the eyepiece it is clearly elongated with a hint of a denser central core area.  This is the brightest of the three galaxies with a visual magnitude of 10.5 and I estimated the dimensions at 4 by 2 arc minutes.
The Palomar 200 photo at the right shows little detail of the galaxy. I suppose this somewhat normal of ellipticals as they are relatively homogeneous in stellar density except for the extreme edges where the density falls off rapidly. I believe this is what gives the galaxy the appearance of having an overly large core or halo.

I look forward to revisiting these galaxies next fall to see if any of the structures visible in the photographs are visible with a more concerted effort through the eyepiece.

Clear skies;
rw

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