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Post by Chicago Astronomer Joe on Jun 8, 2011 21:33:54 GMT -6
It's all about the Knobs
My Bob's Knobs order came in this morning..
Pretty quick, less than two days!
I trust I selected the proper type of knobs, as I don't have the "Fastar" knobbed secondary housing and it is an older model C11. I'm not in a rush to install them, but will soon...perhaps after the Star Party this weekend.
Details when I do.
Chicago Astronomer Joe Founder, Administrator and Chief Astronomer
Telescope/Observatory Docent Facilitator Adler Planetarium & Astronomy Museum
Astronomy Instructor Instituto Del Progresso/IHSCA
Astronomy Program Instructor British International School of Chicago /Lincoln Park Campus
Resident Astronomer Chicago Park District Nature Oasis/Night Out in the Parks/ 606 Trail
Post by Chicago Astronomer Joe on Jul 3, 2011 6:44:26 GMT -6
Installation of Bob's Knobs...
I thought I would install the knobs early Sunday morning. It was a clear sky and good to test out the new replacements.... although very hot and humid...
As shown, I indexed the knobs before installing them with a groove and filled it in with White Out....(Yea, I still have some). This way, I can visually see where what the knobs are doing and use the marking for future collimation reference.
I must admit, it was a nervous moment when I removed the first screw..
It didn't want to come out when loosened, but with needle nose pliers, I lifted it out. Screwing in the knob, it caught the secondary firmly and screwed down nicely. Removing the second screw was not as easy.
Again using the needle nose pliers, I removed it, but when applying the second knob, it did not want to catch the secondary threads. I needed to push down on the remaining screw on the other side to tilt the secondary up a bit, enough to catch...and then we were home. The third knob went in smoothly and I set them all down finger tight...
I set up outside the garage at 3:30am, polar aligned and dreaded the collimation process - considering the C11 is such a beast, it's difficult to peer through the eyepiece and adjust the secondary at the same time. Not wanting to climb up and down the step ladder again countless times, there must be a better way. So.....
I thought I would use a webcam to assist in this - as I look at the screen while up front near the corrector plate. You can see it was off.. checking out Polaris...
It got me in the general area, but the cam needs to be exactly centered to the eyepiece field..and i was having an issue getting both aligned.
So removing the cam, I did the rest of the collimation reaching from the eyepiece to the knobs...which indeed does make the process easier...and my fingertips were just able to apply enough torque to turn them.
But before I could finish the collimation, daylight was starting to break and I was losing contrast on Polaris.
What to do...
I could save the rest for another night, but it takes awhile to set all this up... or maybe...slew it to Jupiter, high in the East now and see if I could collimate with a planet. I won't get an airy disk or concentric rings, but perhaps banding will make up for it...
And was I right...
At first, the image was greatly skewed and unresolvable, but slowly and incrementally, Jupiter started to form into a recognizable sphere..and with one last 1/8 of a turn on the top knob...it popped into sharp view...
With some minor adjusting of the knobs, I started to view the Great Red Spot nicely...and a Jovian satellite transit near the limb.
A full really nice pictorial of the Jupiter imaging session here: