Post by Chicago Astronomer - Astro Joe on Jul 2, 2010 15:43:33 GMT -6
C11 Post cleaning and Modification shake out session
01 July 2010
01 July 2010
Fellow Chicago Astronomer Bill rang me to take advantage of deep clear Chicago skies - according to Clear Sky Clock. With other things on my mind, I wasn't really in the mood, but rare are the conditions for clear heavens.
Picking me up in his Jeep, bringing along Hongxia to see me, we shove all my equipment in, we take off for Chicago Astronomer site #2, grab some eats on the way and what we saw in the next five hours was amazing!
Eats before seeing.
The skies were remarkably clear, deep and transparent - rarely have I seen such conditions. The Moon had not yet risen, providing the opportunity to seek out D.S.O fuzzies.
No astrophotography this session, just visual.
But first, we needed to re-collimate the C11 - as the cleaning and modification knocked it out of alignment despite marking the corrector plate before removal. A two person job, Bill handled the visual while I adjusted the three screws on the secondary. On a ladder, I turned screws incrementally while we were on Vega. After about 15 minutes, we get the rings concentric in both sides of focus...and stars are now pin-point with no coma.
Sweet.
I had thought that in cleaning, I might have messed something with the mirrors - picking off the oily specks, but no...views are sharp, crisp and remarkable.
The inclusion of the internal flocking of the tube has increased contrast nicely, deepening the background behind stars slightly darker. Well worth the effort and highly recommended...
( A full detailed narrative will be coming shortly on the performance of the new improvements on the C11 - stay tuned. )
With the SCT collimated and deep skies before us, we start - and as our master D.S.O locator - Bill went right to work.
Starting off easy, we catch Saturn before sinking deeper into the muck - displaying good ring plane and banding. Proceeding then to my favorite planetary Nebula, M57. Bright, detailed and with averted vision...I could swear I see tinges of red around the edges. Very cool, the C11 is delivering.
We used the Double Double in Lyra to test the collimation...and it's good - splitting them cleaning. And also testing out some eyepieces for quality from the 32mm down to the 3.2mm. Remarkable, some of the "cheapo" eyepieces performed fairly well.
Slewing to M13 in Hercules, the cluster was big, beautiful and individual stars could be made out nicely.
I observed that if I moved my line of sight ever so slightly, so that the eye cup of the eyepiece would just start to include in the FOV, the stars were sharper and cleaner. I think this is what a "Bahtinov Mask" for the aperture is about, and now desire to make one and try it out. Soon.
The Dumbbell Nebula M27 was next, and the faint ghostly image readily observed and shape recognizable.
M11 - The Wild Duck Cluster was next - sparkling like diamonds.
We also viewed the slant of the Andromeda Galaxy M31/M32- Huge in the C11 and the satellite galaxy M110 - both very bright objects in the scope.
The Moon started to peek over the horizon and quickly, the sky conditions deteriorated, as the deep transparency vanished....
This last shot of the Moon looks like a atmospheric atomic explosion.
The Double cluster NGC 869, the Albireo double (really triplet), The Owl Cluster NGC 457 (E.T.), M11, M22, Lagoon, M7, M92 and some more targets that I have forgotten now were enjoyed throughout the session.
This is interesting.
I think the light is a firefly.
We continue to explore the night sky around Cassiopeia...
Aiming toward Sagittarius, we pick up targets, but the horrible sky glow prevents serious veiwing deep into the heart of our galaxy.
The bag on the weight shaft is a for additional weight. With the three finders on the tube and now the additional grab & control handles...balance is now off. I need to add a 5 lb plate from my gym.
Jupiter popped up, showing us the missing band, although I think I'm seeing the return on the EQ band.
We also explored the Gibbous Moon checking out the terminator from "the other way". Very sharp, although noticing some atmospheric turbulence from time to time. We did spend some time looking at the lunar "boobies" Arago A & B. Lava domes, they were prominently featured along with great riles and ridges. The Moon never gets old.
This was an exceptionally good session and glad I changed my mind and ventured out under the stars.
We go again tonight.
