10 inch Traveler

12 inch f/4.9 Traveling Dobsonian In the image above, the 12 inch box (right) looks larger, but it is not as deep as the 10 inch. Also, the cart gives it a larger look. In reality it is the same volume as the 10 inch Box. The 12 inch is an up-grade First Light-March 30th, 9:00pm - Orion Nebula using the 27mm Panoptic & 14mm Radian In August of 2006, while sitting in the Atlanta Airport, waiting for the connection to Portland, I began to sketch the new Traveling Telescope design. We had just completed our Argentina trip. The Telescope took on a similar origin as the 10 inch. A Classic 12 inch was purchased from Sean's Astronomy Shop. As before, as many components were retained as reasonable. 1/2 inch Baltic Birch was used in the construction. Improvements-lessons learned from traveling to Argentina Rolling-Cart-Adds 2 pounds and bulk, but makes carrying the Telescope from gate to gate in an airport much easier. The Cart is attached to the bottom lid of the box. Flip-up Finder-instead of the separately attaching Finder as on the 10 inch. 3 Split Trusses-reduces weight and assembly time. But by splitting the trusses, the tubes can be transported in the check in luggage instead of being checked on in a separate bag. Nate Currier of Aurora Precision, designed the connectors for the Trusses. Balanced to carry larger Eyepieces-The 10 inch is limited to eyepieces of only 18 ounces and less including a 1.25 inch adapter if it is necessary. Box Lid-Ground Board-The 10 inch had a separate Ground Board too bulky for travel. More on the Ground Board. The 10 inch was originally designed to slide around on a piece of ABS plastic. The purpose was to leave the 17 inch diameter Ground Board behind, saving bulk and 3 pounds. But finding a flat surface for the scope to slide around on is not easily done. On the trip to Argentina, I tried to use the 10 incher's lid as a Ground Board by repositioning the azimuth skids, but the "dog bone" shaped rocker did not permit that. But this is where the lid as a Ground Board idea came from. In Argentina, I eventually used a Hotel Coffee Table as a Ground Board. The scope was so high that it occasionally required a chair to stand on to look through it. The Telescope on the Coffee Table became a "trade mark" for the scope in Argentina. More on the Traveling Eyepieces. At first, light weight traveling Eyepieces was considered a good idea. But after traveling to Argentina, I wished I had the larger Eyepieces. Seeing the Southern Sky is rare for me and is worth the weighty large Eyepieces in the suitcase. More Aperture: The ultimate improvement was the Aperture increase without increasing the volume of the carry on portion as compared to the 10 inch. This was done by discarding the original Telescope's end cap, that was attached to the Mirror Cell. This was not done on the 10. The mirror box on the 10 required a larger box to wrap around the Mirror Cell and tube end cap. The increased aperture gives 44% more light gathering power. In addition, Dave Danskey & I, suspicious that the original Secondary was larger than necessary, independently confirmed that with software and ray drawings. We replaced the 70mm Secondary with a 60mm (approximate sizes). More on the Design The final weight is was about 42 pounds including the rolling cart. The assembled Telescope is about 38 pounds. This is just 2 pounds more than the 10 inch. The carry on portion is about 31 pounds. What the 12 and 10 kept in common was the assembled Cage. Not removing the Secondary for travel requires a larger Mirror Box in order for the Cage to nest in the Box. But the ease of assembly is worth it.	...

			.
			10 inch f/4.9 Traveling Dobsonian Telescope (J-10)


			The 10 inch in "packed mode" The Box holds the Mirror & Spider. This is the "carry on" portion. The Alt-Bearings & Rocker. The long Architectural Tube contains the Trusses. The small Camera Bag contains the fasteners, small tools, Finder, Focuser & Eyepieces. The round disk is the Azimuth Base. The Telescope rotates on an ABS disk that sits on 1/2 inch Baltic Birch.


			The view inside the Box.

			Before & After To build the Telescope, a "Classical Dobsonian was purchased and parts removed and others sold. The parts kept were the Primary Mirror, Mirror Cell, Secondary Mirror, Spider, Focuser, Eyepiece Adapter 2 - 1.25 inch and Dust Cap.
		. The Traveling Telescopes
		The purpose of the design was to build a relatively large Dobsonian Telescope that could travel on an Airliner. I was inspired in part by Steve Swayze who took an 8 inch to the 1998 Caribbean Eclipse and by Mel Bartels 6 inch that went to Africa for the 2001 Eclipse. Both Telescopes were light and clever. A traveling "Dob" has been in consideration for many years. The optical components needed to be carried on for obvious reasons. The remaining components could travel in the check on luggage. The weight limit for the carry on portion was 40 pounds, what most airlines except. Lufthansa only allows up to 20 pounds. Both the 10 inch and 12 inch Boxes weigh about 25 pounds.		...



		The 10 inch was first
		10 inch Telescope-First Light September 18th, 2005, 10:15pm
		The Optical Tube Assembly (OTA) sat on my lap as I aimed the tube at the moon to check that the scope would focus. The Telescope was completed October 6th, 2005


		With my eagerness to put together a Telescope quickly and being on a limited budget, I choose to purchase a 10 inch "Hardin Optical" Classical Dobsonian from Sean's Astronomy Shop and use as many parts as practical for the new Telescope. Only the wood work would be custom. All wooden components were made from 1/2 and 3/4 inch Baltic Birch sheet of plywood.

		Off course the original optics were retained as were the original Mirror Cell and and Spider and Secondary Mirror. The Mirror Box was sized to hold the "nesting" Cage and Spider over the Primary Mirror during transport. The Box size came to 9.25 inches x 13.25 inches x 13.25 inches. Unfortunately, the Mirror Box would weigh 25 pounds instead of the 20 or less that I was aiming for.

		To ensure adequate support under the Cage, four trusses (poles) were placed placed under the Spider's mounting points. 3/4" aluminum poles were used because they were available and seem to offer adequate support..

		I kept the original and not so compact "Crayford" style Focuser saving me $350. The focuser must be removed for transport.

		A thin sheet of "ruffled surface" ABS plastic that can be rolled up, acts as a Ground Board when traveling. For "stay at home", this plastic is place on a wooden board. The Alt Bearings are simply attached to the exterior of the box using "star" screws.

		The Telescope serve it's purpose well. In my mind, it is a large Telescope for traveling and yet it weighs a scant 35 pounds even though it uses a full thickness Mirror and doesn't use exotic materials. It is nearly 25 pounds less than it's original "pressed particle board"/metal tube form. Even more impressive is that it is over 110 pounds lighter than the intimidatingly large and cumbersome 10 inch Torque Tube Telescope built years earlier.

		If it were built more from scratch it would likely take on a lot different look, be quite a bit lighter, but be much more expensive.

		The name "J-10" was chosen by myself & my wife Joni. The J is for Joni. This is a Telescope she & her son use in addition to it being used for Traveling.

		Credits for the 10 inch & 12 inch
		Dave Danskey (right) and Nate Currier of "Aurora Precision" were employed to manufacture the wooden components & supply, Trusses, fasteners & plenty of consulting. Their work is responsible for the Telescopes turning out as good as they did.
		Aurora Precision Nathan Currier, 503-678-6300 / Cell: 503-803-6440 / FAX: 503-678-6300 / e-mail address: nathan@arorap.com

		At 2006 OSP "Walk-a-bout"