Trials and tribulations of a big telescope
Grant (thought he wanted to be Big Dob) Barlow
I bought my first telescope in 1984, a Celestron Super C8. It was fun to use. It was very portable. And, except when trying to find an object north of the zenith, it was fairly easy to use. After a few years I started feeling the pangs of "Two-Inchitis" -- the need of a bigger scope. So in March 1992 I drove to Cleveland and purchased a used 17.5 inch Coulter Odyssey II. Cost of this new scope came to about $9000.00 ($700.00 for the scope and $8300.00 for the truck to carry it). The views were fantastic. But it had a major problem - I could not move it by myself. So using Dave Kreige's directions in "Telescope Making", I made a very nice looking, fairly (barely) portable telescope. I went out with the group to Hebron and Groezinger's every time the weather permitted.
Two years ago I purchased a slide-in camper for my truck and so started my disillusion of owning and using a big scope. I had to remake the mirror and rocker boxes in order to get through the door and I now had to carry every part into the camper. Even though the scope could be disassembled for transport, it was still very heavy, and it still wouldn't fit in a car. What was an easy task now was very time consuming and exhausting. Going out to observe for a couple of hours was not very enjoyable. Re-balancing the scope was another problem. I now needed almost 20 pounds of lead plus friction. (Jack used the friction of my scope as an "alarm clock" to wake us up last spring in New Mexico). Needless to say balancing was now a major problem. The big scope had lost its luster. The final "nail in the coffin" of my big dob was when I purchased a new camper last fall. While I could still get the scope through the door, that was as far as it would go as there wasn't any floor space to place it. Needless to say, I didn't go out at all. It was definitely time for something smaller. On March first I shipped my mirror to Houston.
What to buy? I decided the optimum size would be 121/2". I decided to get either the Deep Space Explorer from Orion or the Starfinder from Meade. Orion could deliver in 2 to 4 weeks, very close to the departure date for this year's New Mexico trip. I decided to call local Meade distributors. Cosmic Connections (Aurora)is apparently not in business anymore. Shutan Camera (214 W. Randolph, Chicago) does not carry many models but will order anything Meade makes. Delivery time for the 10" or 121/2" Dob was estimated at 30 to 60 days. American Science Center (Northwest Highway, Chicago) does not carry anything larger than 41/2". (Scopes on display in their showroom tend to get quite beat-up and parts disappear}. They offered to order anything I wanted but didn't have an estimate of delivery time. I ended up at Astronomics (Norman, Oklahoma}; they had the Meade 121/2" in stock with an estimated delivery time of 7 days. The only "premium" was the additional shipping charge.
Address Correction and Update (April, 1997)
�In the preceding article, the correct address for Shutan Camera should be 312 W. Randolph Street, in Chicago. Also, this article was written over a year ago; since that time, Shutan Camera has considerably expanded the size of its telescope equipment inventory. Currently (April 1997), most Meade telescope models are in stock. Moreover, additional lines of equipment and accessories are available. They also have some used equipment for sale and will take good-quality used items in trade toward the purchase of new equipment. The amateur astronomy community in the Chicago area appreciates Shutan's commitment to our hobby.
The Meade 121/2" Starfinder Dobsonian: The new scope arrived exactly as promised by Astronomics, in three boxes -- the tube, the disassembled rocker box and the primary mirror in its cell. It took about 30 minutes to assemble the rocker box, the only glitch was the flat washers were missing. (If you recall the article in S&T comparing the Meade and Orion 10" scopes, the flat washers were missing there also). The rocker box is made of 3/4" particle board with a white plastic finish (I would not call it "laminate", it appears to have been sprayed on) held together with eight 1-5/8" drywall screws. The ground board bearings are three pieces of Teflon rubbing against the plastic finish. The sides are rather flimsy as screws do not hold well in particle board "end grain." I would suggest that anyone buying an Orion or Meade Dob reinforce the front corners with some "real" wood. The secondary holder was loose and its mounting bolt was bent on arrival. To straighten it, I looked through the hole for the focuser and bent the bolt until the open end of the tube was centered in the secondary. I then tightened the nut and proceeded to mount the mirror cell in the tube. Prior to installing the mirror and its cell, I marked the center of the mirror to simplify collimation. Meade pre-marked one hole with a small dot inside the tube and a matching dot on the cell. While the cell fit very nicely in the tube, the holes did not exactly match up, and with the rather short screws supplied, fastening the cell in place took some time. The screws for holding the cell in place and the collimating screws required an Allen wrench which was supplied. The tube comes pre-drilled for either the Meade 6x30 or 8x50 finder scope. I had to drill one hole to mount the Telrad. Meade includes screws with the scope to mount a finder. These also have an Allen head and an Allen wrench is included. Unfortunately, it was the wrong size. The rack and pinion 11/4" focuser that comes with the telescope is made of high quality plastic with metal used for the rack and pinion. Examining the collimation with my Cheshire eyepiece showed the system to be almost perfectly collimated so I left well enough alone. It was now time for First Light. Sirius was the first object viewed. It was very clear and "pinpoint" sharp. Next I swung over to Venus. I could very easily make out its gibbous shape and it, too, came to a sharp focus. After allowing for twilight to end, I examined M42 in Orion. The four stars in the Trapezium were pinpoints. All these were found by sighting along the tube as I did not have my finder (a Telrad) installed at this time.
On Saturday, March 9, after an almost two year absence, I took the new scope out to Hebron. Examining Sirius with high power revealed classic diffraction rings both inside and outside of focus. It received the highly distinguished Rich Burns Seal of Approval. A final test of mirror quality was to search for the 5th and 6th stars in the Trapezium. They were easily visible using about 120 power.
Four years ago I purchased the Odyssey II because of its (low) cost. What I really wanted back then was what I have now. Why didn't I get a 121/2" then? Mainly cost and they were not readily available. I now have something that has good light gathering ability and most importantly is portable.Published in the April 1996 issue of the NightTimes