Saturday, August 28, 2010

Solar report August 28th, 2010

The monsoon weather pattern remains intact here in the Old Pueblo, which means that there is no nighttime observing.  This year we are actually ahead of the average annual rainfall, and for that, even the amateur astronomers are grateful.  Personally I can't wait for a good clear night so that I can try out the new to me 12" LX200 SCT that I recently purchased...tune in next month for a review of this scope.  And, if you are interested in buying a nice 9.25" SCT, by all means send me an email!

A quick shameless self-promotion...Lunt Solar Systems, the manufacturer of my solar telescope, maintains a blog on the company website.  Yesterday, yours truly was the subject of the blog...check it out here: Sky to Paper

This morning I set up my solar telescope and was treated to nearly perfect seeing.  The atmosphere was unbelievably stable and even at the highest powers, details on the sun remained sharp.  It may have been the most stable solar observing session I have had, since purchasing the scope.  Transparency was not quite as good as there was a bit of haze in the eastern sky, but this is typical this time of year with such high humidity in the desert.  I completed the sketch below at 1530 UT (8:30 AM MST).

There is only one officially numbered active region on the face right now, AR 11101 in the northeast.  This region contains a very dark spot, that at high magnification appears to be splitting in two.  It will be interesting to watch this spot over the next 24 hours.  To the northwest of the spot, there are three small areas of plage.  The southern two of these areas are separated by what appears to be some bi-polar filamentary structure. Again, this could be a sign of increasing activity in this region, and it may develop into a distinct active region over the next day.  There is also an area of plage in the southern hemisphere, although this area did not display any signs of activity and may be what is termed an ephemeral region.

Cai-Uso Wohler, a solar observer and imager in Denmark, captured the photo below about 5 hours before my observation, and posted it on the Cloudy Nights Solar Observing forum.  You can see that the sunspot in AR11101 was not yet showing any signs of dividing.

Monday, August 23, 2010

Weekend Sun

I had a pretty busy weekend as I spent Friday night and all day Saturday working at the Mount Lemmon Sky Center.  Friday night we had a SkyNights program and Saturday saw the Discovery Days event.   To the left is a picture of the current 24" RCOS telescope.  Excitement among staff at the Sky Center is increasing  as in mid-September, this telescope will be taken offline and a new 32" will be installed!  If the quality of the mirror is as good as the 24", visitors to the observatory will be in for quite a treat.  I am told that this telescope will be the largest telescope in Arizona that is solely dedicated to public observing, education and outreach. Pretty neat if you ask me.  Below is a picture I took outside the dome (about a week ago) and you can see the moon as well as Venus.

Anyway, Sunday morning I was fairly tired from the events, but the sky was as clear as it had been in two days and I decided to pull out my solar scope and make a sketch of the sun.  My sketch was completed at 1535 UT (8:35 AM MST).  While there is a mildly active region in the southwest (AR 11100) that includes two dark filaments, I was rather impressed with the large prominence in the northeast.  Of course, my sketch to the right does not do justice to the ethereal nature of this prominence.  Fortunately, a solar observer named Michael Buxton in California made a time lapse video of the prominence and posted it on you tube.  Check it out!

Friday, August 13, 2010

SkyNights volunteering and observing report

In an earlier post I mentioned that I have recently been volunteering at the Mount Lemmon SkyCenter, assisting with the SkyNights public observing program on the 24 inch RC Optical Systems Ritchey-Chr├ętien telescope seen at right  (Photo credit to Adam Block/Mount Lemmon SkyCenter/University of Arizona (Board of Regents)).  Last night the sky center hosted an extended version of the SkyNights program where in addition to the standard educational and viewing program, guests brought lawn chairs and loungers to relax and stretch out under the stars to observe the annual Perseid Meteor shower.  We were very fortunate in that the weather pattern has been holding steady this week, and we were treated to a sky devoid of clouds, with better than average seeing conditions.  The shower certainly displayed several long and colorful meteors for the guests, however, in my opinion the shower was better on Wednesday night and early Thursday morning.  Regardless, all the visitors had a good time.

Another benefit of this extended program was that there was less of a rush to see objects at the telescope for the visitors.  We had more time, and folks were occupied looking for Perseids when not at the eyepiece.  The summer milky way dominates the view right now and guests were treated to most of the showpiece objects of the summer sky. They observed the Lagoon Nebula, the Swan Nebula, globular clusters M22 and M13 (the great Hercules Cluster), the Dumbbell, Veil and Ring nebula, as well as open clusters such as the Wild Duck and the Butterfly.  Of course, everyone was awed by the king of planets, Jupiter.  As the night wore on, most of the guests departed and a few very interested folks remained.  These folks were interested in seeing some of what the 24 inch RCOS could do, so we took a look at some advanced observing targets.

We aimed the scope at the ring nebula and using a 17mm Nagler eyepiece (297x) we attempted see the magnitude 15.7 central star.  Sure enough, with careful observation, 3 of the 4 of us spotted the star with averted vision!  This was quite exciting as I had never seen this star before.  Given the patience and ultimate success demonstrated by these guests, I then slewed the scope to M33, the Triangulum galaxy (image at left).  This galaxy is a very large  face on spiral galaxy, but has a very low surface brightness.  Using a 31mm Nagler eyepiece (153x) the galaxy filled the field of view.  Looking through the eyepiece I was able to detect the spiral structure of the galaxy as well as 5 of the brighter star forming regions in the arms.  If I had been alone and had time to study the galaxy I am sure I could have seen much more, but I was mostly looking for features quickly so that I could assist the visitors in observing the galaxy.  All 3 guests were able to enjoy the detailed view.  Since they were appreciating this more advanced look through the telescope we spent some time looking at other deep space targets.  I can not remember all of them, but we were treated to fantastically detailed views of NGC 6888, the Crescent nebula;  a picturesque view of NGC 7331 and the 4 accompanying galaxies that comprise the "deerlick" group; dust lanes in the Andromeda galaxy, and amazingly, structure in NGC 7662 the "Blue Snowball" nebula!

When the last guests departed I went back to NGC 7662 to make a sketch of what I was seeing.  This is a fine example of a planetary nebula and at 297x displayed a striking aquamarine color.  It is very large, about the same apparent size as Jupiter.  Most shocking to me was that there was a bright arc within the nebula itself as well as a bright knot in the southern portion of the outer halo.  This nebula is about 5000 light years away in the constellation Andromeda.  Here is my sketch as well as an image of the nebula:

My colleague Mike Terenzoni who was leading the program suggested we look at NGC 891, an edge on galaxy in Andromeda.  I had observed this galaxy before in my 9.25 inch SCT and it was always an attractive but faint target.  We slewed the scope over, inserted the 31mm Nagler, and the view about knocked my socks off.  What was always a faint smudge to me, was a bright and beautiful edge-on galaxy with a dust lane that bisected its entire length.  Most often when observing dust lanes one sees subtle differences in contrast that take experience, patience and averted vision to see.  Not so tonight!  This dust lane was dark and readily visible with direct vision.  The galaxy is brighter toward the core, and below is my sketch as well as an image.

We had a few minutes left and decided to take a look at Jupiter one last time.  Mike had a new Tiffen FL-D filter that we attached to the 31mm Nagler to improve contrast- and it worked splendidly.  While the seeing conditions had dropped to about average, we were still treated to a pleasing view of Jupiter that now featured the great red spot traversing across the disc.  There was no way that I could capture the details that we observed in a sketch, but I decided to give it a try.  Typically, Jupiter sports two dark cloud belts, named the north and south equatorial bands.  For the last couple months, the south equatorial band has vanished (this is very uncommon, happening most recently almost 20 years ago), although there are some indications that it may be reforming.  There is a dark band of material immediately south of the great red spot, and the spot itself is clearly sitting in a hollow.  The north equatorial band remains quite dark yet does show some disturbance toward the preceding limb of the planet.  Below are my sketch (completed at 0723 UT 8/13/2010), as well as an image posted on the internet from a little while after my sketch.  You can see that I need some practice in terms of getting the features into a more accurate latitude, but I am pleased with this attempt.

 All in all, it was a very fun evening, and if you have read this far I hope that you will sign up for one of the SkyNights programs...

Wednesday, August 11, 2010

The Girl with the Dragon Tattoo

I just finished reading The Girl with the Dragon Tattoo by Stieg Larson, and can honestly say that I enjoyed the book quite a bit...coincidentally, the weather has given us a bit of a break over the new moon and the last two nights have proven to be cloud free after 9 PM.  Even better, the atmosphere has been incredibly stable and transparent at the Lost Pleiad Observatory.  So, with Lisbeth Salander on my mind, I put my Celestron 9.25 inch SCT onto the mount and enjoyed exploring some heavenly bodies, in the constellation Draco (the dragon). Bad joke, I know.

One of the galaxies that I have observed before from dark skies is NGC 5866, and I was curious what this edge on galaxy would look like from the suburbs.  This galaxy is perhaps most well known as it may have been the galaxy that French Comet hunter Charles Messier originally  identified as object number 102 in his catalog.  NGC 5866 resides approximately 38 million light years away, is nearly edge-on and has a visual magnitude of 9.9.  While it was not nearly as bright as I recalled, the nucleus was evident and the galaxy appeared about twice as long as it did wide.  While there was no sign of the dust lane that bisects this galaxy, it did appear to bulge slightly more to the southwestern side than to the northeast.  To the left is a sketch I made at 180X.

I observed a second edge-on galaxy in Draco, NGC 6503.  While not having the history of NGC 5866, this galaxy is an interesting target visually.   It is listed at magnitude 10.2, yet appears to me brighter...perhaps a full magnitude brighter.  It was featureless in my scope showing a uniformly illuminated surface oriented roughly northwest-southeast.  At 17 million light years, it is less than half the distance of NGC 5866 above.  The galaxies are very close in apparent size, which indicates how much larger NGC 5866 must actually be.  To the right is my sketch.

I observed several other objects, including Jupiter which is starting to be reasonably high by midnight.  There has been much discussion of the south equatorial belt and it's recent disappearance, yet last night it looked as if the band may be re-forming.  The red spot was transiting during my observation and preceding it, just to the south of the spot was a thin dark band stretching approximately 1/3 of the way across the face.  I would have sketched it, but I was getting sleepy.  Maybe tonight?

Saturday, August 7, 2010

Solar Flare Report

It is better to be lucky than good!  Yesterday our dog Cosmo tore up a bunch of drip irrigation and the burrow of our desert tortoise trying to corner something or other...(Don't worry the tortoise is fine).  So this morning I spent a few hours fixing the irrigation and renovating the burrow.  By the time I set up my Hydrogen Alpha solar telescope, I was hot, sweaty and rather fatigued.  I was planning on a quick look just to check out the prominences that I have been hearing about.  Normally I observe around 8:00 AM local time as the atmospheric conditions are more favorable and it is not so blasted hot.  Today, I set up about 11:15, and...holy smokes, a MASSIVE flare was erupting throughout active region 11093.  My sketch was completed between 1820 and 1905 UT (11:20 AM - 12:05 PM local time) under average to below average seeing conditions.

There are currently four active regions (AR) on the face of the sun: 11092, 11093, 11094, and 11095.  AR's 11092 and 11095 appear relatively weak, with faint plage and a small spot in each.  AR 11094 is very close to the northwest limb and is moderately bright with a filament connecting with some small prominences off the limb.  While the northeast prominences are quite large and beautiful and would normally be the feature du jour, 11093 was, as mentioned, in the midst of an M 1.0 class flare!  The plage was very bright, much brighter than I can capture in a sketch, and the whole region was involved in the flare.  There was also a very dark filament curving through the region, and a dark spot on the proceeding edge (the west).  The flare lasted from 1748 UT to 1845 UT with the peak at 1824 UT (11:24 AM local time).

Thomas Ashcraft captured several images of the flare and stitched them into an 8 megabyte .gif movie that is highly recommended!

Ken Florentino of Colorado captured this HD movie and posted it on YouTube~

Below, I have inverted my sketch to match the images of the flare.  (Through a refractor telescope, images are reversed east-west at the eyepiece and that is the reason that these space based images have east to the left).

My Sketch
Solar Dynamics Observatory 304

Solar Dynamics Observatory 171
Prior to flare

Friday, August 6, 2010

Astronomy Sketch of the Day

There is not a lot of observing going on this week as the monsoon weather pattern does its thing...which is fill the sky with dark clouds, blow around a lot of dust, and then sprinkle just enough that your car is a mess from the blown dust.  I did awake today to a nice astronomical surprise, however, in that my sketch of the sun in hydrogen alpha from July 31st was featured as the August 5th Astronomy Sketch of the Day! (Follow the link!)

The Astronomy Sketch of the Day website is in the same vein as the very famous Astronomy Picture of the Day website.  Amateur astronomers from around the world submit sketches that they have made while observing and each day one is selected as the sketch of the day.  Certainly in this age of astrophotography, there are many fewer individuals sketching at the eyepiece than taking photos.  Nevertheless, I was quite tickled that my sketch was featured.  As they say, every dog has his day!

The music is playing on this award ceremony, but before I am kicked off stage, I want to thank my good friend Jerry Farrar who is my mentor when it comes to sketching and observing the sun; truth be told, he is my mentor in quite a few aspects of visual amateur astronomy.

Tuesday, August 3, 2010

The William Optics 28mm UWAN

I tend to get a little stir crazy during the summer monsoon as far as astronomy goes- I am spoiled living in the desert southwest with many clear dry nights.  So when a few weeks go by with no opportunity for night time observing I turn to other aspects of my hobby (addiction) for entertainment.  Having already cleaned the observatory a few times (you could eat off the floor) and having already installed a nice new shelf from Target to hold some of my books and stuff, I made an impulse buy and acquired a used William Optics 28mm UWAN eyepiece.  I had heard good things about it from other TEC 140 users so when I saw one for sale on Astromart I asked myself  "Do I need this eyepiece?"  I quickly answered myself saying "Self....No.  No.  A thousand times, no.  You already have a very nice 31mm Baader eyepiece"  A few hours later I had made the deal and it would soon be shipped.

After a week of cloudy nights, the weather gods took pity on me, and the past two nights proved to be fantastically clear with very good seeing and no moonlight until after midnight.  I used the opportunity to test this new eyepiece extensively in my TEC 140 and what follows are my subjective observations and experiences using this eyepiece.

I decided to compare this eyepiece to my Baader 31mm Hyperion Ashperic which is obviously similar in terms of the power it delivers in the scope.  The picture to the left gives you an idea of the relative size of the monster in comparison to the Baader 31mm, and a can of Pepsi...keep in mind that these eyepieces both have 2 inch barrels, so you can see how physically massive the 28mm UWAN is.  Before I provide you with my subjective impressions, I'll give you some of the objective information as taken from the respective companies, as well as some of the exit pupil, power, and field of view calculations for the scopes I own.

Eyepiece                      William Optics 28mm UWAN                  Baader Planetarium 31mm Hyperion Aspheric

Manufacturer info          William Optics                                          Baader Planetarium
Price Retail/Used          $339/$250                                               $189/$150
Eye Relief                     18mm stated                                            18mm stated
Weight                         1000 grams (2lbs. 3 oz.)                           390 grams (13.8 oz.)
Apparent F.O.V.           82 degrees                                              72 degrees

Using TEC 140 (f/7)
     Exit pupil                  4mm                                                         4.5mm
     Magnification           35X                                                           31X
     True field of view     2.3 degrees                                              2.3 degrees

So now that we have the objective data out of the way, how did the eyepiece perform for me? My conclusion first...Overall, I am quite satisfied with the 28mm UWAN, and will be selling the Baader 31mm.  The Baader is a very, very good eyepiece for the money, however, the 28mm UWAN does most everything just a little better.  You can see from the data that these eyepieces are very close in both magnification delivered, exit pupil and field of view- so the differences that I am about to describe are my subjective experiences using the eyepiece.

Prior to explaining why I preferred the views in the UWAN, there are some ergonomic issues worth noting in the event you are considering one or the other of these eyepieces.  First, is the aforementioned weight.  The Baader weighs less than a pound, and is remarkably light for an eyepiece with a 72 degree apparent field of view.  The 28mm UWAN is over 2 pounds and will impact your telescopes balance.  Second, while the stated eye relief is 18mm for both eyepieces, the experience using them is quite different.  To the right is an image of the eye lenses and you can see that the UWAN eye lens is slightly smaller and you may be able to tell that it is recessed into the eyepiece top.  When using the 28mm UWAN, it does not feel like one has 18mm of eye relief.  In fact, to see the field stop, I have to place my eye almost all the way to the housing.  This is not an issue for me as the lens itself is recessed and my eyelashes do not touch.  I also find myself tilting my head slightly to get the best position to see the entire field.  The UWAN has a very smooth twist up eye-cup, however, I can not use this as if it is up at all I can not see the entire field of view.  The Baader 31mm is very comfortable to use and the eye relief measurement seems accurate.  For public outreach the Baader 31mm would be a better choice on its ergonomic characteristics alone.

On to the views, and the reasons why I prefer the 28mm UWAN.  I observed several types of objects with both eyepieces- nebula including M8, M17 and NGC 7000; planetary nebula including M57, M27, and the young, small NGC 7027 in Cygnus; Globular clusters including M22, M13, M20, M5, and NGC 7006 in Delphinus; The Veil supernova remnant NGC 6992; and the galaxy NGC 7331 in Pegasus. Observations of faint nebula were made both unfiltered and with my Baader planetarium UHC-S filter.  

I'll present my findings in descending order of the perceived difference.  In other words, I'll address sharpness first as I felt this was the greatest difference in the background will be second as I felt this was the second greatest difference.  Last will be color as I felt there was no difference in eyepieces.

First, the Baader 31mm is very sharp on axis, however, stars in the outer 25% of the field of view increasingly look like little flares as they approach the edge.  The 28mm UWAN on the other hand was sharp all they way past 90% of the field of view.  Even the outer 10% of the field was not nearly as distorted as in the Baader.  In terms of sharpness, the 28mm UWAN clearly had the edge (pun intended).

The second thing I noticed when using these eyepieces was that the 28mm UWAN revealed a darker sky background.  I was surprised by this given that the eyepieces are so close in focal length.  This was an obvious and marked difference between the eyepieces.  Had I not perhaps been unconsciously biased to look at sharpness first, the sky background may have struck me immediately.  

Third, and I hate to use such a subjective construct, was faint detail.  When observing star clusters, there were not any stars that I noticed in one eyepiece that I could not see in the other.  That being said, there were faint stars that were easier to see in the 28mm UWAN...easier than the magnification difference alone would dictate.  I do not know if it is related to sky background, coating differences, or anything for that matter.  Contrast is a touchy subject when discussing eyepieces and I am trying to avoid using that term...but faint detail was easier to see in the 28mm UWAN.  Nebula in particular were brighter and faint extensions were more readily seen in the 28mm UWAN.  This was most noticeable when observing NGC 6992, the eastern portion of the veil.  Also, the lagoon nebula (M8) revealed more structure in the UWAN.  To the left is a sketch I made of M8 using the UWAN 28mm and the Baader UHC-S filter.

Finally, I looked for differences in how the eyepieces rendered star colors.  With fainter stars within clusters I could not tell a difference between eyepieces.  I did point at the bright and colorful double Albireo and could not detect a color difference between eyepieces on this bright pair either. 

In conclusion, the William Optics 28mm UWAN is an excellent eyepiece for use in an f/7 refractor.  It is significantly more money than the Baader 31mm, but in my opinion, the views are worth the difference.  The Baader is more comfortable to use for a beginner or a member of the public at an outreach event, however, for the experienced amateur, the UWAN does manage to quickly get out of the way and let one observe.  Unless something is radically different in my f/10 SCT, look for the Baader Hyperion on the used market soon.