February 16: By late afternoon I was able to resume construction. I removed the clamps from the filter slide assembly and installed it into the upper cage. I centered it between two uprights to ensure a comfortable eyepiece angle when observing objects at lower altitudes.
Next, I applied the two-sided tape to adhere the light baffle. I found it necessary to trim about 1/8" from one end of the laminate. The installation of the spider, secondary holder, Telrad and focuser completed the upper cage assembly, and also brought to a conclusion the assembly of the TeleKit 13.

The finished telescope...

...minus the optics.

February 17: I decided to sleep in on this cloudy President's Day, so I didn't begin working on the telescope until mid-afternoon. After a few hours, I had completed the following tasks: center spotted both mirrors; installed the secondary mirror in its holder; installed and centered the primary mirror in its cell; applied a 'spot' on the upper cage directly across from the center of the focuser drawtube; squared the focuser to the upper cage; squared the spider assembly; positioned the secondary holder laterally under the focuser; and positioned the secondary mirror rotationally under the focuser.
That brings me to the point of balancing the telescope and performing optical collimation. With all components attached, I determined that the scope is heavy at the primary end, and will require about 4 pounds to achieve balance. That, and collimation, will wait until Tuesday.

February 18: In order to make the process of collimation easier, I decided to balance the telescope first. I added 5 pounds to the top end, and it is balanced acceptably. It's not perfectly balanced, but the weights are just a temporary solution.
I will be adding a 9x50 finder scope, so I began constructing the wooden mounting board. It has been epoxied, and will cure until tomorrow. Then it's time for sanding, sealing, and applying the urethane.
In order to get familiar with the collimation of this scope, I performed each step in the process a few times - using both the light pipe-sight tube and the laser.
It was cloudy all day long, but in the evening it started to clear up... so, I decided that tonight would be first light! I optimistically wheeled the scope to the backyard around 21:30, turned on the fan, and began assembling the accessories as the mirror cooled down. Since I still have some final 'adjustments' to make, I knew that this session would not be protracted. I simply wanted to receive some visual confirmation that the last 3 months efforts had not been in vain.
After tweaking the collimation with the laser and aligning the Telrad with the assistance of Betelgeuse, I inched over to the great Orion Nebula. Even with an abundance of moonlight raining down I was treated to a simply breathtaking view of this old friend. The trapezium appeared as four pinpoint beacons amid the nebulosity that stretched beyond the edges of my nearly 1° field of view (actually about 51' at 60x). The detail was apparent throughout, even in the wispy 'wings'. Next up - Jupiter. A stunning display of symmetry with Europa and Io to one side, and Callisto and Ganymede to the other, with the orange bands providing stark contrast to the black background. Finally, I gave in to the bright call of Luna... I headed for the northeast quadrant, where the terminator divided Mare Crisium. A brief look at Picard and Peirce before leaving the Sea for Cleomedes. The terminator sliced across the mountains presenting magnificent shadows. Traveling northeast upon the TK-13, I traversed the high ridges into Burckhardt, before ending my little lunar odyssey at Geminus.

February 19: Sanded, sealed, and applied the first coat of urethane to the finder scope mounting board. Also applied a coat of flat black paint to the inside bottom of the rocker box. The paint extends up about an inch on the sides as well.
Last night's first light revealed a problem with bringing eyepieces to focus when fully inserted in the focuser. My original conclusion was that the focal length of my primary is a little longer than the 59½" specified by Discovery. But, after working with Bill (Discovery) and Randy (AstroSystems) it was determined that the mirror is not the problem. Apparently the mirror box was cut a little short - it should have been 17½" tall, but it is only 16". Once the situation was identified Randy offered to make a new set of truss tubes (that are 1½" longer) and ship them right out. Until then, the scope is completely usable by sliding the 1¼" eyepiece adapter back slightly in the focuser. The longer truss tubes should also alleviate some of the imbalance at the front end.

One coat done on the finder scope mounting board

A coat of black on the inside of the rocker box.

February 22: The finder scope arrived today; an Orion 9x50 right-angle, correct image unit. After installing the mounting board next to the Telrad, and installing the finder scope, the weight imbalance is now about 4 pounds. Tonight I'll get an opportunity to really test the new scope - at EVAC's local star party.

9x50 finder scope ready for action.

TK-13 stored until next time.

February 28: When I got home from work today, a package was waiting by the door. It contained the new truss poles from AstroSystems. They are 1½" longer than the original set - to accommodate the focal length since the mirror box was cut 1½" short. Unfortunately, the necessary wooden dowels were not shipped with the truss poles. So, off to Home Depot again. They did not have a dowel in the required diameter, so I bought one that was a close match. My finishing sander, a block plane, and a rasp... and about 2 hours of time - and I had new dowels. I epoxied the dowels into the truss poles and set them aside to cure. Tomorrow I'll reassemble the poles and, weather permitting, test them.

March 1: With the dowels firmly epoxied into the tops of the new truss poles, I applied a coat of flat black paint for purely aesthetic reasons. Once the paint dried, the poles were pre-drilled for attachment to the upper truss fastener plates. The scope was then assembled using the new truss poles. There still exists a 2 pound weight imbalance, necessitating the use of a counterweight at the upper cage. But, all of my eyepieces can now achieve focus when fully inserted. As with the original set, the new set of poles were numbered to facilitate collimation. Unfortunately, the weather relegated my testing procedures to daytime observations of distant power lines.

March 5: The National Weather Service (along with weather.com and my Clear Sky Clocks) indicate that we should have clear skies this weekend, along with daytime temperatures in the low 80°s... watch this space for an update on using the new scope!
The weather was great over the weekend; warm in the daytime and mild overnight, but the seeing wasn't very good. Still, I managed to log a few eyepiece hours over the weekend. Since the last time I had the scope out, I have acquired a 2" UltraBlock filter. I installed it into one of the lower positions on the filter slide, only to find out that it would not fit inside the assembly. After posting on the TeleKit users forum, I have discovered that others have experienced this problem. I will have to remove the focuser and the filter slide assembly, and make some modifications. Oh well, a Dobsonian is never really finished...

April 16: After having used the TK-13 for a few weeks, I determined that I really miss tracking. It's not so bad when using low power, but when I want to do some critical observing... well, the ability to track objects is a necessity. So, after considering all of my options, I am having a very talented local ATMer (and fellow SAC member) build an equatorial platform for me. It is currently in the design stages, and should be ready in June. I can hardly wait! I'll update its progress here.
Another new addition to the TK-13 is imminent: digital setting circles. Hopefully UPS will deliver my Sky Commander setup this week. I hope to have it operational for this weekend's EVAC local star party. More details on the Sky Commander coming shortly.

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© 2002, 2003 Peter Argenziano, all rights reserved.
Page last updated on 16 April, 2003