Posts Made By: Allen Tracht

Bringing this to the top: Has no one used such a hitch-mounted platform to carry a telescope?

Thanks -- Allen

Soon, however, I realized that my eyepieces were in jeopardy: If the case were inverted, or even if it were picked up too suddenly by its handle, the eyepieces could fall out of the plate and be damaged.

I couldn't come up with a scheme to lock the eyepieces down to the plate, so I instead decided to raise each eyepiece a custom height so they would all be pressing against the eggcrate foam in the lid.

I first thought to make wooden rings that would connect to each other with brass pin to form adjustable-length tubes. I soon learned that routing small rings is harder than it looked.

I also tried making tubes out of beveled wooden strips. Again, this involved a lot of labor and was not very attractive when I was done. I finally concluded that no matter how much I liked the look of wood, wooden tubes would require either a lathe, or much more patience and skill than I posses.

So, I switched to acrylic. Extruded acrylic tubing with a 1/8" wall thickness is readily available in both 1-1/4" and 2" ID from U S Plastics, and I already had some 1/4" (actually about 0.220") acrylic sheet which cut easily on my table saw.

I started by planning my layout. In anticipation of a Nagler 31, I allowed 3.3" in diameter for two of the 2" eyepieces, and 3" for the rest, and 2.5" in for each 1-1/4" eyepiece.

Once I got the layout right on my computer, I started drilling by drilling a 1/16" hole at the center of each eyepiece position. Then I used Forstner bits to drill 1-1/2" and 2-1/4" holes as needed. The holes were started on one side and then the plate was inverted to finish the holes from the other side, to make the cleanest holes possible.

Even with lots of lubrication (I found cutting oil to work better than water) I had to stop every few holes to allow the bits to cool. I knew that the bit was getting too warm when the shavings were softening and becoming sticky.

Here's the plate, all drilled, with the protective plastic film still attached:

Now, all I had to do was to measure each eyepiece and cut a piece of tubing so that the eyepiece inserted in the tubing, with the eyelence cap on, would be 5.75" tall. The longest tubes were for the 1-1/4" adapter and the Nagler 3-6 zoom. The shorted tubes were for the 55 Plossl and 35 Pan.

The off-the-shelf tubing fit snugly in most of the drilled holes. One was a little loose, but that shouldn't be a problem. One hole was too tight, so I opened it with a brake master cylinder hone that I picked up at a local auto-parts store.

Here's my plastic "pipe organ":

Here's the case, fully assembled and populated. The new plate is slightly narrower than the old, and so the equipment area to the right of the eyepieces is now larger. It's equipped with dividers that were supplied with the case.

Now I don't worry about carrying my eyepieces.

On the other hand, I made a couple of inquiries as to the basic specs (size, weight, FOV) of their 80mm super-finder and never got a response, even after calling and speaking with a real person. Now, it was explained that Vic was having some personal problems, but I was assured that I would get a response. When I didn't, I felt like I was being ignored because I was inquiring about a second-hand, discontinued product that was an attempt to make lemonade (finders) out of lemons (lenses that weren't up to spec).

I hope things are indeed better and that, if I resubmitted my inquiry, it would be answered, but the question is moot.

Allen

Chair, first, and then DSCs (for me):

Trying to find diffuse objects in suburban skies, DSCs are a tremendous help. With my limited horizons and bright skies I rarely have enough stars to reliably hop to a target and even if I do, the poor contrast makes it very difficult to find an object by sweeping. OTOH, if the DSCs can put an object into the FOV, then I can concentrate my efforts on seeing if it is at all visible. On an unusually clear night, I was able to see M110 this way, after several previous attempts failed.

Allen

Is there a great advantage to a longer-focus Dob? With, for example, a Starstructure 18" F/4.3, the zenith eyepiece height is only 77". A chair for that height might still be a custom item, but it would seem to be safer than one 8' high.

For star parties, I really like any scope mounted on my G-11/Gemini. The Gemini has the advantage of being able to align on virtually anything. With a rough polar alignment (by compass), I can first align on the sun (with a solar filter, of course) and then the moon or a bright planet. I can then start showing these objects well before sunset.

As far as scopes go, I find that the aperture of my previous 8" Newtonian or current C9.25 is more appreciated than the wide-field, sharp views of my FS-128. (The FS-128's wide field was a hit during last June's Mercury-Venus-Saturn conjunction.)

A focal reducer or 2" visual back for the C9.25 helps to enlarge the FOV.

Allen

If it were set for a non-tracking mount, it would drift by about 15 arc-seconds per second. Perhaps that the drift is different might offer a clue. Could the computer's clock be bad? I've seen XP systems that have gotten confused and ran their clocks at 2 seconds/second. -- Allen

Jim,

I assume you know about AAAP. If not, check http://www.3ap.org/

Allen