DEEP-SKY OBSERVING AND OPTICAL PERFORMANCE

Of course, the most important thing about a telescope is that it perform to its potential... you can invest thousands in the fitting out of a telescope but it isn't worth a penny if it performs as if your kid just pulled it out of a box of cereal.  Making the decision to purchase a telescope without knowing anything about it is a gamble, especially if you can't find any information about it from someone who has experienced it first hand.  This telescope was one of those gambles for me... but a gamble that seems to have paid off with interest.

First light was from a lonely overlook along the Blue Ridge Parkway in the mountains of south-western Virginia. The spot that I had chosen was at an elevation of about 3200 feet and the view was stunning, both overhead and down in the valleys below.  The sun was already hugging the horizon and I hurried to get the telescope on the mount.  The accessories and eyepieces used for this first-light testing of the Startravel-150 were an assortment that included the following:

GTO 2-inch mirror diagonal with 1-1/4 inch adapter
Orion Shorty-Plus APO 3-element 2x Barlow
Orion 1-1/4 inch V-Block Anti-Fringing Filter
Orion 1-1/4 inch SkyGlow Broadband Light-Pollution Filter
Orion 2-inch Optiluxe FMC 40mm eyepiece
Orion 1-1/4 inch Sirius Plossl 25mm eyepiece
Orion 1-1/4 inch Sirius Plossl 10mm eyepiece
Antares 1-1/4 inch WideView -70 Series 5.7mm eyepiece
GTO 1-1/4 inch LE (Long Eye Relief) 2mm eyepiece

The first eyepiece to enter the diagonal was the big Orion 2-inch Optiluxe FMC 40mm.  This eyepiece has a 62mm AFoV (apparent field of view) and has been my very favorite for sweeping, deep-sky views ever since I got it about a year ago.  I turned the telescope toward the zenith and as I brought the image to focus, I was a bit disappointed to see that there was not good, clear black sky between the stars... until I realized that I was not looking at sky-glow but at thousands  and thousands of tiny points of starlight between the myriad of brighter stars!  I was aimed right at a bright section of the Milky Way and I was looking right down the barrell of one of its spiraling arms.  The view seemed noticeably brighter than in my Orion 120ST.   I quickly did some math in my head and figured that the light gathered by the big 6-inch refractor was somewhere in the area of 40-50% more that that of the 120mm refractor... With the greater light gathering capacity, how much better would it be for galaxy and nebula hunting?  As if to answer this question, I began to notice that there was a darkening of one part of the field of view and I suddenly realized that I was looking at none other than the "Gulf of Mexico" within the complex known as the North American nebula.  I glanced up and confirmed that I was aimed right at the tail of the great swan Cygnus...  "Mexico" and "Florida" were very well portrayed and filled the view.  The Optiluxe's 62mm AFoV with its 40mm focal length coupled to the Startravel-150 produced a true field of view measuring 3.3 degrees: an impossible task for an 8-inch  Schmidt-Cassegrain telescope (SCT) without the use of one or more focal reducers.   This was figured by taking the AFoV (62-degrees) and dividing it by the magnification (18.75x).  With some slight scanning to one side, there was a hint of the Pelican nebula that is part of this tremendous glowing mass of ionized gas...  

I turned south and easily spotted the Trifid and Lagoon nebulas...  The Lagoon was especially bright and it was easy to see numerous dark lanes within the glowing cloud and the embedded star cluster was very bright and sharp.  As I was about to turn northward to hunt down M-51, headlights turned my way as a big Chevy Suburban turned into the overlook.  The driver instantly turned off his headlights and slowly coasted to a stop and turned off the engine.  As I uncovered my eyes, I heard him say, "Sorry, I didn't know you were here... did I trash your night vision?"  It would appear that I was not the only person who had designs on this dark site as the figure stepped down from the big SUV and went around to the back of the vehicle.  He introduced himself as Robert and started to unload what turned out to be a Meade 8-inch f6.3 (1250mm focal length) LX200.  Can you say "control scope"? 

As he finished setting it up, I told him what my project for the evening was and he was delighted to help me make some comparisons between the two telescopes, even if it was an "apples to oranges" type of comparison.  As soon as he had it up and running, he slewed the SCT to the Lagoon and brought it into focus with a Meade Super Plossl 40mm and I put the Orion Sirius Plossl 25mm in the Startravel-150.  Both views were just about the same scale with mine at 30x and his at 31.25x.  There was a definite difference with the Sky-Watcher showing a sharper and more contrasty view and detail in the nebula was more easily seen.  We both agreed on this and the mutual conclusion was that the refractor's lack of a central obstruction was the winning factor.  After a while, we decided to hunt down some galaxies and I said that I wanted to find M-51, even though it was well down into the sky glow that hugged the horizon.  

I placed the 40mm Optiluxe back into the diagonal and pointed the telescope to where I knew the Whirlpool sat just off the tip of the handle of the Big Dipper.  On the first glance into the eyepiece I saw two  small, fussy patches of light off to one side of center: I had found M-51 and its companion on the first try and placed the 25mm Sirius Plossl back into the diagonal.  The galaxies seemed to just sit there in space with only a few stars to keep them company.  Again, we compared views: lack of contrast in the SCT seemed to obscure the galaxies all together in the sky glow over the horizon while the refractor, although it was of lesser aperture, seemed to pull the Whirlpool and its companion out of the haze and M-51 was actually showing some structure, hinting at one of its spiral arms.  I really wished that it was spring and not the late summer as it would have been much higher in the sky and would surely have shown more detail once it was out of the haze...  Ok, off to the things higher up and closer to the zenith: M-13 and the Ring Nebula were next on the list.

I quickly found the globular cluster M-13 almost directly overhead with the 40mm Optiluxe.  The thing that amazed me was that it was a bit difficult to pick out the cluster from all the other stars at that wide 3-degree field of view!  I upped the magnification to the 25mm Sirius Plossl and then on to the Antares WideView -70 Series 5.7mm for a magnification of just a hair over 131x.  This eyepiece has always surprised me with its 70-degree AFoV and has always struck me as exceptionally bright with very good contrast.  At 131x, the true field of view was just slightly over 1/2 a degree... about the size of the full moon.  M-13 stood out beautifully with many stars being resolved all the way down to the core.  Compared to my partners 8-inch SCT, more stars seemed to be resolved and the image was much sharper... the refractor had produced far superior contrast once again and that was all that was needed to bring the stars out of hiding.  Again the target changed and the Ring Nebula was our quarry...

Here I had problems finding my target.  To be honest, I had never tried looking for it before and didn't know exactly where to point the telescope.  I knew that it would be overhead relatively close to M-13 but I couldn't find it to save my life.  Here is where I got a hint of scope envy as Robert just pressed a few buttons and the LX-200 buzzed right over to the Ring in a few seconds.  After he had confirmed he had hit his target, he came over and took control of the Startravel-150.  With the 40mm Optiluxe, he found it and said, "Have a look."  At first I couldn't pick it out and he said to me, "It's damned tiny but keep looking... move your eye around in that big eyepiece of yours."  I followed his direction and then I saw it!  It was not what I had expected... I had thought it would have been much bigger but its surface brightness was surprisingly high and it really stood out once I had found it.  I put in the 26mm Sirius Plossl and re-centered the ring and looked at it a bit longer... very pretty but still very small.  I took out the 26mm Sirius Plossl and inserted the Antares 5.7mm Wideview and re-centered... there it was.   Pretty ring with a bit of structure to the oval of the nebula!  It struck me as one of the loveliest things that I had seen thus far with this telescope, with its sharply defined edges, and it was just beautiful standing there all by itself.  My friend's SCT showed a similar view at slightly higher magnification and the detail seemed about the same between the two telescopes.  I sat there a while and gazed at my pretty little ring for at least five minutes until I was snapped out of my daze by the sound of the LX-200 slewing to another target...  "M-31 is up!"

I looked to the East and saw Andromeda climbing above the sky glow.  Once again I slipped in the big Optiluxe 40mm and swung the refractor toward M-31 which was now quite visible to the naked eye.  As I looked through the eyepiece, I couldn't help but say "wow."  The core was very, very bright and the disc of the galaxy stretched its glow from edge to edge of the field of view.  Plain as day, the two small companion galaxies M-110 and M-32 were right there with her... one a soft oval of light turned at an angle and the other a brighter, more compact round thing to the other side of the giant core of the galaxy.  at this magnification, I could make out a definite "edge" to M-31 caused by a lane of dust.  With careful scrutiny, I could make out the "potato chip" curled ends of the galaxy.  I wondered if I could bring out a little more detail by upping the magnification...  In went the 26mm Sirius Plossl and now I could make out not just one but two dust lanes in the beast.  The galaxy showed several knots of brightness separated by dark lanes within the outer regions of the disk itself: this was detail that did not show up in the 8-inch f/6.3 LX-200.

We continued on into the evening comparing the views between the two telescopes on several more galaxies, star clusters and nebulae.  In all instances, the Startravel-150 kept up the pace and quite often won out against the LX-200.  As midnight approached, Robert said that he needed to go but would like to look at one more thing through the Startravel-150.  I obliged and he slewed the telescope to the north-east and then he said, "Just as pretty as I thought it would be."  He had captured the Double Cluster.  It was absolutely stunning!  Both clusters fit in the field of view and there were countless, bright and colorful stars to be seen... red, blue and yellow ones.  I could not think of anything nicer to end the evening with than a jewelry box of shiny gems in the sky!  We looked at it for a little longer and then he said that he really had to go and so I helped him pack up and we exchanged e-mail addresses, promising to get together again in the near future.  As I was getting things ready to go home, I noticed the open cluster of the Pleadies rising above the horizon: I knew that the great nebula in Orion would soon be following...  It had been a successful first test of the Startravel-150 and I really didn't want to wait for Orion to rise but, somehow, I convinced myself that it would be a shame to wait several months for the dead of winter to get a look at the grandest nebula visible from my latitude.  It was now almost one o'clock in the morning and I was starting to feel the chill of the moist night air.  Mid-September nights can get really cool at this elevation  (I had only brought a hooded sweatshirt to keep warm) and I decided that the best thing to do was get into the Firebird and warm up for a while.  I set the alarm on my cell phone for 4:00 AM and took a nap after I had shut-down the engine.

I was awakened by the theme from the original "Star Trek" series playing on my phone (gotta love modern technology) and stepped outside of the car.  I looked up to the eastern sky and saw the great constellation of Orion looming over the still mountain landscape.  As I approached the telescope, I became terribly aware of the heavy dew that had settled over everything as I had dozed... the objective!  In my haste to get a nap, I had forgotten to cover the objective with the dust cap.  I uncapped the Optiluxe that was still in the diagonal and was pleasantly surprised to find that the dew shield had done its job perfectly: the view had no sign of dew accumulation on the objective lens.  I turned on the drive and swung the telescope to the sword of Orion and peered through the eyepiece...

The entire sword of Orion fit in the view and the nebula, M-42, was glowing brightly against the dark background of space.  I inserted the 25mm Sirius Plossl and re-centered the nebula.  The increased magnification brought out more detail and I was able to see the bright region of the Trapezium with growing anticipation... I quickly moved up to the 10mm Sirius Plossl.  Now the nebula was really starting to fill the view and numerous bright and dark regions were showing their magnificence.  The scimitar-shaped edge of the nebula was quite apparent and the comma-like feature of this vast complex of gas and dust, M-43, showed itself nicely.  I removed the Sirius Plossl and inserted the Antares WideView-70 Series 5.7mm eyepiece and centered on the Trapezium: what was to greet my eye put a smile on my face.  The trapezium region showed tremendous detail and all four stars were split cleanly.  The squared outline of this region of the nebula was crisply defined and the turbulent nature of the cloud here was quite apparent.  I was to find that the brightness of the nebula  seemed to be very high at this magnification.  I pulled my eye away and noticed that, without a doubt, I had lost a good bit of my dark adaptation in my viewing eye.  I threaded the Orion SkyGlow Broadband filter into the Antares WideView and reinserted it into the diagonal and had another look.  The entire view was transformed and the nebulosity jumped out at me as I scanned the entire complex.  As the image presented here  faithfully demonstrates,  the detail shown in the trapezium region of the great nebula is quite astounding with the SkyGlow filter in place.  What had already proved to be an impressive view had now turned into a stunning feast for the eye...  Contrast, although quite impressive before, was now pushed to the extreme.  M-43 was to stand out against a pitch-black background  showing at least one dark lane cutting into its curved edge.  The "fish's mouth" of M-42 seemed to gape, threatening to swallow its smaller companion and the whole nebula of M-42 showed detail that I had not thought possible as it took on a pseudo 3-D appearance.  This telescope had now, without a doubt, proved itself a true deep-sky performer and had given me the best view of the Orion Nebula that I had ever seen, besting any 8-inch SCT or Newtonian that I have looked through and it had met or exceeded the performance of the LX200 8inch f6.3 on every object  viewed this night in a side-by-side comparison.

Before I called it quits, I decided to swing the telescope toward zenith and find a bright star to do a rudimentary star test.  I picked out a second magnitude sun and worked up the magnification to 375x with the GTO LE 2mm.  I screwed in the Orion V-Block violet rejection filter to help counter false color from the fast achromat and brought the star into focus.  Focusing was a bit of a chore as, at this magnification, the slightest touch sent vibrations down the legs of my light tripod and the star danced frantically all over (I have since replaced the aluminum legs with heavy wooden ones and this is no longer a problem).  Once focus had been achieved, the vibrations dissipated in about three seconds or so.  The star was a very bright airy disc with three concentric rings of light getting dimmer and dimmer to the outside... good alignment on this telescope.  Inside and outside of focus showed what proved to be identical images with one bright outer ring followed by numerous rings falling inward getting fainter and fainter as they got closer to center: a very well figured achromat doublet  showing no  over or under correction, pinching of the optics, spherical abberation  or any other discernible defects.

Lunar and Planetary Observing Part 1