Tuesday, December 31, 2013

DYI alternative to Bob's Knobs for my Celestron C8

Instead of buying Bob's Knobs to aid with the collimation of my C8 (original Orange tube, pre-1980) I went to the nearby Ace Hardware store here in La Pine, Oregon. There I found the correct sized screws with sufficient sized knobs on them to easily adjust the secondary mirror without having to use any Allen wrenches! Cost: $1.80 (compared to $20.00 + shipping!)

As you can see, you can get them in short enough lengths to make it possible to put the scope's cap on and still be able to make adjustments.

NOTE: NEVER remove more than one knob or screw at a time! You will likely be in a big mess when you do! Remover ONE and IMMEDIATELY replace it BEFORE moving on to the next.

BONUS: When I check the collimation after installing my "Richard's Knobs" (LOL) the scope just happened to be in correct collimation! Didn't even need to adjust the knobs after installation! Cool!
But in case I need to adjust the collimation, I am ready!

How I made fine adjustments to the vertical polar alignment on my C8

It can be really difficult to make fine adjustments to the polar angle due to the weight of a telescope on the wedge. I have an old Celestron 8 on an old Celestron wedge. It does not have the ability to make fine adjustments on the polar axis.
Then I realized that I could just loosen the three bolts that hold the scope base to the wedge and slip in a metal washer between the scope base and the wedge (but not through the wedge bolt). I could then re-tighten the bolts, thus making just a fraction of a degree adjustment!

It turned out that it was all I needed to get sufficiently polar aligned to use the prime focus and even a Barlow for photography purposes up to 2 minutes of exposure.

Also note that I removed the big Allen screw bolt with an equally sized standard bolt with a big knob that makes quickly adjustments like this possible.

Where did I find the proper sized bolt and knob? At your friendly ACE hardware store, of course!

Working on getting the Celestron C8 polar aligned

Had just a little bit of clear skies tonight and so I opened up the observatory about 5:45 pm and took some wide angle shots of the sky around the Pleiades. Got up to 3 minutes of exposure without noticeable star-trailing.

Here is the full frame view
Canon T2i
ISO 1600
1 minute each
40 mm

Here is a heavily cropped shot of the Pleiadies (less than 10% of the original photo), three images stacked with Deep Sky StackerCropped heavily, and some post-processing (not all that great)
Seeing was poor, clouds moving in, and heavy atmospheric moisture.

Comet ISON

Captured Comet ISON just before it dropped too low to photograph
November 22, 2013
Canon T2i
5 sec

Comet Lovejoy

Took this photo of Comet Lovejoy from my La Pine Observatory on November 15, 2013.
Canon T2i
ISO 6400
30 seconds