Sunday, September 26, 2010

Mount Lemmon Sky Center update

I have had a hard time posting this month, due to being incredibly busy as well as being limited in my observing time.  One of the things that has taken up more of my time has been volunteering up at the Mount Lemmon Sky Center (MLSC).  Previously I have posted about my efforts up there, and the week of September 13th, the 24" RCOS scope went offline as the new 32" RCOS Schulman Telescope was installed!  I spent a bit of time up on the mountain during the installation of the scope and thought that these pictures may be of interest.

Above you can see the telescope assembled with the west fork arm opened up.  This fork arm contains the optical encoders that communicate the telescopes position in declination to the computer.  The east fork arm (not shown) contains the declination motor and brake.  One of the neat things about this telescope is that it operates with friction drives and is therefore very quiet and has none of the periodic error that is inherent to geared drive systems.

Above left is the secondary cage and the approximately 12 inch secondary mirror.  In the mirror you can see reflected the primary mirror covers.  These are opened and shut electronically and the scope was not yet operational when I took these images, so no picture of the primary mirror yet.  Above right, is the brains of this telescope...this box contains a computer, drivers, and all the electronics necessary to communicate with the mount and telescope. 

Finally, this pictures was taken several nights later when we went up to do some adjusting of the polar alignment of the mount. You can see how massive the scope is in relation to the computer desk to the right.  This scope is the largest scope in the State of Arizona dedicated solely to public outreach and education.   One of the reasons I have been spending so much time at the MLSC of late, is that in addition to the typical volunteer duties assisting with outreach programs, I am now training to begin conducting the SkyNights programs!  It is very exciting and quite a bit of work.  While the telescope is impressive, it is simply a tool that we use to provide guests with an opportunity to learn and experience the night sky in ways that they never have before.  Mount Lemmon is a fantastic location for this program. Just as satisfying as hearing a guest exclaim "WOW!!" when seeing a globular cluster for the first time, is the contemplative silence of guests as they appreciate that their own shadow being cast on the ground is actually blue and not grey or black.  I can say that I learn as much as the guests each time I am there. As evidence, take a look at the picture below.  This picture was taken just prior to sunset looking opposite the sun in the sky, to the east.  In it, you will see a mountain range in the distance, as well as what at first glance appears to be a second, higher mountain in the background.  Look closely and you will see that it is not in fact a high mountain in the distance;  Rather, it is the shadow of Mount Lemmon being cast on the atmosphere.  This is just one example of something that can be experienced at the MLSC, something that most people have never seen before.

Saturday, September 11, 2010

103P/Harltey Update!

Cometary update! I had a chance to get out last night and take a look at this comet again (see the previous post).  It seems to be slightly brighter than my previous observation, as I was able to hold it in direct (as opposed to averted) vision.  The coma appears to be a bit brighter to the north, however, there is no central condensation to the comets nucleus that I could see.  NASA's Jet Propulsion Laboratory maintains a website where one can generate orbital diagrams for this comet, and they indicate that the comet is currently .317 AU from Earth, and 1.244 AU from the sun (and getting closer!).  The comet is moving approximately 1.67 arc seconds per minute across the sky, so it does not yet appear to move that far from night to night.  I estimated the comet to be between magnitude 10 and 10.5 and it is in the constellation Andromeda.  The sketch was completed at 0508 UT on 9-11-2010, which was 10:08 PM MST on 9-10.

Sunday, September 5, 2010

Comet 103/P Hartley

In November of this year,  the EPOXI mission spacecraft will make a close flyby of comet Hartley 2, also known as 103/P Hartley.  The EPOXI name is a combination of EPOCH (Extrasolar Planet Observation and Characterization) and DIXI (Deep Impact eXtended Investigation).  The goal of this flyby is to gather data that will help us understand the structure, formation and composition history of cometary nuclei.  This information is important as it relates directly to our increasing understanding of the origin of our solar system.

This comet is predicted to reach naked eye brightness in late October, perhaps as bright as magnitude 5.  Last night night I decided to see if I could spot the comet in the LX200 12" SCT as it is currently well placed in the constellation Lacerta.  I had downloaded ephemerides for this comet from the IAU (International Astronomical Union) Minor Planet Center which indicated that the comet may currently be as bright as magnitude 8.5.  I was a bit skeptical as I had "googled" this comet and there are not many amateur images out there, suggesting that it is not exactly an interesting target...yet.  Gary Kronk maintains an excellent site called Cometography and there is information on this comet as well as a couple of images if you are interested.

Despite my skepticism (unusual, I know) I slewed the scope over the comets location and saw...nothing.  I decided to completely shut off the dim red lights that were on in the observatory and increase the magnification to 234x to darken the sky background in the eyepiece.  Sure enough, there in the center of the eyepiece was the faint glow of the comet.  My sketch of this comet is at left, and you will probably need to click on it so you can see the full size image.  It was hard to sketch such a faint glow, one that was essentially seen using averted vision.  It was also difficult to ascertain the size of the comet as it was extremely diffuse with no central condensation visible.  I would estimate that this comet is closer to magnitude 10-11, as it has a very low surface brightness...but again, I do not know the extent of the comet, so any estimate of it's magnitude is more of a guess than anything.  I completed this sketch at 0346 UT on 9/5/2010 (which was 8:46 PM MST on 9/4).  I should mention that the sky conditions were excellent with seeing that was estimated at 4/5 and a level of transparency that was as good as it gets from my location on the city's perimeter.  The milky way was visible from Sagittarius through Cygnus and beyond.

After spending some time on the comet I decided to have a look at NGC 40, a planetary nebula in Cepheus, also known as Caldwell 2.  Since I installed the 12" SCT I have been having fun observing planetary nebulas looking for features that were not visible to me with my previously smaller telescopes.  NGC 40 is a wonderful target, one that deserves more popularity.  The 11.6 magnitude central star is visible in most telescopes, and it is surrounded with a large circular shell of nebulosity.   As you know from previous posts, planetary nebula often hold up to greater magnifications without breaking down as other targets do, and NGC 40 was no exception.  I observed NGC 40 using an 8mm Ethos eyepiece, which in the 12" results in  a magnification of 381x and a field of view of .3 degrees.

You can see in the sketch that at high power the nebula is no longer a neat circular haze, rather it has bright arcs on both the east and west sides.  The arc on the west is the brighter of the two, and it seems to arc away from the nebula to the south in a manner reminiscent of a galactic spiral arm.  This planetary nebula is approximately 3500 light years away and spans a diameter of 38 arcseconds.  If you have never observed this target, it is highly recommended.

Thursday, September 2, 2010

The Meade LX200 12 inch SCT!

The rumors are true... Introducing the Lost Pleiad Observatory's new Meade LX-200 12 inch Schmidt Cassegrain Telescope.  This telescope is well traveled, having started its career several years ago as a research instrument at the Arkansas Sky Observatories.  When it was retired from research it was sold to a private individual who used it for a few years before deciding to pass it along.  I had been looking for a larger SCT for some time and when I saw this scope advertised, decided to take the plunge.  It has been optimized  through several modifications, such as the two cooling fans which have been installed to circulate filtered air behind the mirror.  This aids the mirror in reaching ambient temperature. The stock focuser bearings have been upgraded to provide very smooth focus with minimal image shift, and the interior of the optical tube has been flocked to eliminate internal reflections and scattering of light.

Above left is the business end of the scope where you can see the the focal length is 3048mm resulting in an F/10 instrument.  The center image shows the cooling fans and on the right you can see the internal flocking.  I have had an opportunity to test the scope out over the past three nights, and without hesitation I can say that it is the best SCT I have owned.  Both my original 8 inch and the 9.25 inch that I have been using were fine performers, yet this scope is in another league.  Certainly the aperture increase is significant, however, planetary images in this scope are sharper than either of my previous SCT's.  In addition, contrast is excellent and the fine detail that I have been able to observe from my backyard has been rewarding. While splitting double stars is the realm of my TEC 140 refractor, this big blue monster has impressed me.

So far I have sketched two objects observing through this instrument.  For my first light sketch (to the right) I decided to attempt M27, the Dumbbell Nebula. This was the first planetary nebula discovered by Messier and is one of the showpiece objects of the summer sky.  This nebula is approximately 20,000 years old, a baby in astronomical time. I observed this nebula with and without my Baader UHC-S filter to bring out some of the nebular extensions.  The magnitude 13.9 central star illuminating the nebula was easily visible as were about 10 other stars within the nebulosity. 
Planetary nebula are fuzzy objects, and typically hold up well to higher levels of magnification than other targets.  I was observing NGC 6818, the "Little Gem" nebula in Sagittarius and decided to pump up the magnification and see if what was a small, circular, light blue fuzz-ball at 234x may reveal structure at 609x!  Typically one would not use magnification that high, but decent seeing combined with excellent optics transformed the nebula from a featureless disc into a nebula reminiscent of M57, the Ring nebula. To the left is an image of this nebula, while below are my sketches of this "Little Gem" at 234x and at 609x.  For reference in the high power sketch, the stars to the NW and SW of the nebula are magnitude 12.5, while the star to the east of the nebula is magnitude 13.5.