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Taking your telescope to a dark site without a car


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Taking your telescope to a dark site without a car

Article/review by Heinz Radeke, Tokyo

This has been my problem since I live in the middle of Tokyo. Here, most stars are all but invisible. I have no car, because it is of little use in this city, and I would rather spend my money for other nice things such as telescopes. So in order to observe, I have to travel by train and bus to a dark site. This means, I have to put my telescope into a backpack. At first I thought about photo backpacks, because they are nicely padded and have adjustable compartments. The problem with them is, however, that they do not have the shape of a telescope, so longer tubes than about 40-50cm don't fit. I am using a Takahashi CN-212 Cassegrain-Newtonian as well as a Mewlon 250. The length of the OTA is in both cases 85 cm including the focuser and the finder scope. Diameter is 24,3cm at a weight of 8.5kg for the CN-212 and 28cm / 12.5kg for the Mewlon. I wanted to carry these scopes to a dark site without a car. Not only the OTAs themselves, of course, but the whole lot including the mount, tripod, eyepieces, binoviewer and other accessories.

What to do?

I believe I have come up with a solution that might be interesting for others, who are in a similar situation, drowning in light pollution, longing for dark skies, but no car.

My solution is backpacks for musical instruments. They come in various shapes, and they are made to carry delicate instruments, so they are usually heavily padded. Most of these have one disadvantage, namely the lack of a sophisticated carrying system. They are mostly built for short distances, so they only have shoulder straps but no hip belts, and if they do have hip belts, these aren't padded. This means that if you want to carry a larger heavier scope in the range of 10-15 kg, the weight would cut into your shoulders. Wikipedia writes:

"Large backpacks, used to carry loads over 10 kg (22 lbs), usually offload the largest part (up to about 90%) of their weight onto padded hip belts, leaving the shoulder straps mainly for stabilising the load. This improves the potential to carry heavy loads, as the hips are stronger than the shoulders, and also increases agility and balance, since the load rides nearer the wearer's own center of mass."

I believe, I finally found a company, FUSION bags, which produces backpacks for musical instruments that can be used for heavier (and for that matter also lighter) telescopes of varying sizes and weights up to, say, 15 kilograms. Their backpacks have the best harnesses I have come across so far, in particular they sport a good padded hip belt, in addition to padded shoulder straps. I have seen too many bags with just unpadded weak looking shoulder straps. Impossible for heavy gear like a larger telescope.

In my case the most suitable bag was one originally intended for a bass trombone. You can see it at this link;

Fusion bass trombone backpack

And here is a Youtube video showing its features:

Video


Picture 1

This bag is heavily padded on all sides with soft styrofoam-like plastic with a thickness of 3cm. See picture 1. These paddings take up a lot of space, which is no problem with a bass trombone, but my telescope just couldn't enter the bag, although the dimensions were right. Fortunately and ingenuously, however, all the paddings are in pouches that can be zipped open, so they can easily be removed and/or replaced with thinner material. I removed all of them, except the one at the bottom, because that's the point that takes most of the weight of the rear heavy mirror telescope. Now I have a perfect fit and still enough padding to give some basic protection to the sides of the scope too. To be on the safe side, I am planning to buy some thinner padding material at a local DIY store of about 1cm thickness, cut it and put it into the pouches of the backpack. I expect even the Mewlon 250 to fit into the bag. I will receive this scope in a few weeks from now. Without the removed padding, the whole backpack weighs just 2kg! I tried to carry it. Very easy.


Picture 2

In picture 2, you can see how this backpack works for the CN-212. There are three extra pouches on the outside, where a laptop, or whatever else could be stored. There is even space for three eyepieces, originally intended for trombone mouthpieces.

As a light weight yet very sturdy mount I have found the iOptron ZEQ25 with a 5kg counterweight and a 4 kg battery pack which doubles as a second counterweight. The whole thing, including everything, weighs 20kg. You can see this setup in picture 3. The ZEQ25 is a new concept with an excellent load capacity of 12.5kg (the weight of the Mewlon 250), but low own weight of only 4.7kg. Experiences have shown that even imaging is possible at the limit of its capacity. See the following thread:

ZEQ25 thread

I am planning to put the tripod, mount, counterweights, eyepieces, binoviewer and other accessories into a Samsonite suitcase on four wheels (a "spinner"). The lightest one weighs a mere 3kg, so the whole thing stays under 25 kilos and can be carried up and down the stairs in the various train stations, just like an ordinary piece of luggage.

In this way, I will be able with a relatively large scope, to travel by myself by train and bus anywhere.


Picture 3

UPDATE - 8 Nov 2013:

In the meantime I have collected some experiences with the combination of the Takahashi CN 212 and the iOptron ZEQ25 mount. My impression is, that the weight capacity of this month has been somewhat overrated by the company. I have too many vibrations when I observe visually, especially of course at higher magnifications. This makes focusing rather difficult, to a point where it is sometimes nearly impossible. I would therefore not recommend this mount for OTA's of the of the Takahashi CN 212, or to mention the Mewlon 250. My guess is that the load capacity of the ZEQ 25 is closer to 15 lbs than to the nominal 27 lbs, especially with longer OTA's. Please don't get me wrong, it is a very innovative design and I love it for what it is, but I believe I'm going to wait for a heavier edition of this mount before using it seriously for the CN 212.

Yet, I have found another very stable and still portable solution, the T-Rex AltAz mount made by Kokusai Kohki in Kyoto (see picture 4). With this setup, I have practically no vibrations at all using the CN 212 or even the Mewlon 250 (although the latter does show some jitter at very high magnifications). For visual observation, the mount is a breeze to use. The slow motion controls work very smoothly, finding objects with the sky commander is easy, and a tracking motor is in the pipeline. The mount can also be used with Sky Safari. Counterweights are not necessary.


Picture 4

I am very happy now. While I'm waiting for its bigger brother, I'm still going to use ZEQ 25. I'll just take care not to touch the telescope while observing and to avoid strong winds.

Heinz Radeke


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