"Caracas Astronomica, Astronomia desde los cielos de Caracas Venezuela,Planetas, Estrellas, Asteroides, Telescopios"

This passion for the “bricolage” does not cover the accessories or “add on” only, rather in reality it begins with a complete telescope construction and in some cases of considerable sizes (24 or 30 inches aperture), including the mirror and optic elements modeling. These techniques are developed to such level than some Amateur are considered as true professional experts in optic, mechanical engineering and astronomy. Freeware software to design telescopes and their optic are available on the Net, for those who want to embark in this task. As an example you can try Plop by Dale Keller, for Newtonians or Reflectors telescopes. Plop can be downloaded from here and Dave's Webpages are here.
.

Accessories tray detail on Celestar tripod.
The tray is supported by the tripod’s arms and the adjusting axial screw.
You can observe the protective fillet of plastic (like those employed on vehicles doors) used in order to give a best finishing.
Some additional holes for eyepieces could be done (1-1/4 and 2 inches)
.

that suggests when the focuser is moving in or out. The NGFS does not come with an installed optical encoder, so was necessary to do a mechanical adaptation on its axe in order to move the adapted encoder and send the pulses toward the interface. In order to avoid this adaptation, I designed a little oscillator circuit based on a LM555 that is connected to the interface in the encoder's entrance. In this way the oscillator sends an impulse to the interface every 10 milliseconds, the microcontroller uses this signal as a counter to control the focuser position, however this method is not so precise as if with the optic encoder's use.

The DC motor is controlled using an H bridge built with discreet components. Nevertheless, integrated chips with this type of circuits for motor control exist. The interface size could be reduced around 50% by using this kind of integrated chips but they are difficult to find in Venezuela.

This is the LX200 emulator.

Most of the guiding software used to correct the telescope’s tracking error during the imaging sessions, are compatible with Meade‘s telescopes. This interface permits the use of these softwares using a standard ST4 guiding port.

Meade is an American company, whose philosophy of products development is Legacy or proprietary, doing his architecture totally closed. For example, all the included software with the DSI camera (Color, Pro, Color II and Pro II) is designed to be utilized with the Autostar protocol and as a consequence with Meade telescopes. The LX200 emulator will translate these commands to basic instructions that any telescope with a ST4 port may understand.

It is connected to the computer's serial port and it is based on an ATMEL microcontroller and a relays board to turn on and off the ST4 circuits. In his original version, the emulator includes two extra relays for focuser control with DC motors like the NGFS, but it does not have feedback to determining its position. My version possesses 4 LED diodes that indicate the movement direction (N, S, E, W) and an internal option to bypass the emulative plate and leave the relays control to the computer's parallel port, turning it into another type of guiding interface. In this last case, the compatibility with LX200 is lost.

A Webpage where you can find a complete project for these emulators is here. You will see that there are interfaces with Serial and USB options just like kits for sale.

As we added the above electronic elements, the quantity of transformers and necessary cables to energize them increases in that proportion.

Using an ATX-350 Watt PC power supply, I built a multiple power source to feed the telescope and all the accessories.

These power supplies have

voltage signals quite stables and clean, in addition to give enough potency and security for this application. In order to turn on the ATX power supply manually the green cable on the main plug should be connected to ground, then using the main switch you will be able to turn it on and off. I have installed five 12 Volts output terminals (only one is shown in the image).

Making good use of the power supply and in order to avoid another external box, one variable oscillator was built inside it. This oscillator runs from 1 Hz to 1 Kz and is used to feed a PWM (Pulse Width Modulation) circuit of a heater for dew removing. This Dew Heater is installed on the C8's correcting plate. The circuit has a power stage that is connected to an enameled cable coil, that is working like a heater and helps to avoid correcting plate blurring. It is not the case of Caracas, but if the ambient temperature at the observation place is very low (around or underneath 0 degrees Celsius) it would be needed another type of heater, perhaps based on resistors.

Collimation is the mechanical process where the optic’s train elements are adjusted, aligning them of manner such that the optic amplification power be maximum.

The collimation in catadioptric telescopes as Schmidt Cassegrain (SCT) is made by adjusting the axial axis of the secondary mirror.

The Celestar (like other SCT marks and models) has 3 screws arranged in a triangle shape and a central pivot to do the setting. The problem with this is the fact that the mirror is hanging practically from these three screws. Doing some pressure out, we can give more stability to the secondary assembly. With this in mind, a helicoidal spring coil was placed as it shown in the figure. This was resulting in a more precise and durable collimation

We must take care that the spring be rustless. Those used in good-quality lanterns are ideal.

One frequently ignored aspect by the amateurs when trying astrophotography is the correct telescope system balance.
The counterweight system must permit that the telescope system stays practically in place with the RA's and DEC clamps loosen. This will reduce the system axis torque.
Only a little tendency to fall East must prevail (West in the southern hemisphere), existing a force opposed to the follow-up or tracking direction.

Good balancing favors the quality of tracking very much minimizing errors and improving the backslash.
The system observed in the photo was built using a guide or support for Spots lamps. The steel rustless screws that support the counterweights (silver-plated) are setting by using an aluminum plates “sandwich”. The guide or support is riveted to an aluminum plate of 7mm of thickness that is screwed in the underside of the telescope's tube using threaded existent holes. A cutting and light dubbing permits adapting the plate to the tube's curve.
The counterweights are workout weights. Note that one of them is set in asymmetric way (out of axle using a hole threaded at one side of it) in order to compensate the weight unbalancing in the RA axis.
The system allows adjusting counterweights, raising or lowering them by mean of the screws or else moving them back and forward. Finally, because the counterweights can be set out of his axes a third option of setting is present, from there the term of 3D.

This adapter for a guidescope was commented on the Observatory page. In spite of the used materials, the support offers a good rigidity and stability.

All of it is manufactured with MDF wood (high density water resistant wood agglomerate). The vertical supports have 1 cm. in width, cut following the main telescope curve (C8).

The longitudinal base was made of MDF 5 mm. width. The rings supports are 1 cm MDF cut with a lot of patience. They have those "cup" shapes in order to provide an easy way to place the supporting screws and nuts that attach the rings to the base.

The rings come from a 6 inches PVC piping junction. Using a metal lathe was possible to extract 4 perfect and equal thickness rings. The guidescope supporting and adjusting screws are 5 mm diameter, are made from rustless steel and have Allen heads. In order to build the threads on the PVC rings, holes smaller than the supporting screws were made. The threads on the PVC holes were built forcing the screwing.

The plastic stoppers are from old color markers, and are intended to protect the guidescope body surface from the screw tips in order to avoid paint damage when adjusting.