Moravian Desiccant Container, standard mounting with tool

Moravian Desiccant Container, standard mounting

This desiccant container allows for quick and more comfortable desiccant exchange, so less precious night time is wasted.

The desiccant container used in the Gx cameras allowed for easy opening, pouring-out the desiccant (typically silica-gel) and replacing it with a freshly baked one (the container is designed to easily accept even the very hot silica-gel without any possibility of temperature-induced damage of the container). However, this operation typically required removing of the camera from the telescope or at least positioning the camera (and thus the whole telescope) so it is possible to pour-out the used desiccant and then repositioning it again to be able to pour-in the fresh one. But removing the camera and connecting it again to the telescope have some unpleasant consequences, like the necessity to acquire new flat fields.

Newly designed desiccant containers keep the desiccant in the removable part. This allows to just unscrew the container with the desiccant without the necessity to remove the whole camera from the telescope.

The desiccant is kept inside the container by a screwed perforated cap. This brings two important advantages:

To regenerate the desiccant, the whole container can be "baked" in the oven after the O-ring has been removed.

It is easy to replace the desiccant (silica-gel) in the container in the case of wearing-out (or damaging of the silica-gel with too high temperature etc.). It is enough to unscrew the perforated cap (perhaps with a coin), pour-out the desiccant, pour-in the fresh one and screw the perforated cap back. Then the container can be either baked or screwed into camera head, providing the new fresh desiccant is properly dried.

A little drawback is somewhat longer time necessary for the desiccant do dry-up the CCD chamber.

Note: The latest revisions of all G2, G3 and G4 cameras also use unified desiccant containers, so the very same container can be used on all models. However, with the introduction of the Enhanced cooling cameras with bigger heat sink and thicker back shell, also the desiccant container have to be longer. So there are special (longer) variants of both standard and tool-less containers for Enhanced cooling cameras available. They are linked in the recommendations section.

Now, storing containers with baked desiccant is possible:

Also introduced is an optional cap which allows sealing of the container after baking if it is not immediately mounted into the camera. The cap is equipped with the same o-ring sealing like the piece on the camera CCD cold chamber. So if it is not possible to immediately attach a container with regenerated desiccant to the camera, it can be sealed with the cap.

Alternative: new modification for eaay handling:

The new desiccant container construction also allowed introduction of a new modification of the container. The standard container, supplied with the camera, is equipped with a slot for a tool to allow it to be released and unscrewed and later screwed and properly tightened. This container does not overhang the camera head outline. This could be important when the camera is used in e.g. in the secondary focus of the fork-mounted Cassegrain telescope etc. If the space behind the camera is not important, the alternate variant of the container can be used. It is somewhat taller, but allows tool-less manipulation.

The tool-free variant brings one limitation — it is necessary to remove it (and thus un-seal the CCD cold chamber) when the camera back shell has to be removed. Also the camera cannot be laid flat on the back when e.g. exchanging filters in the internal filter wheel etc.

This alternative version can be found in the recommendations section below.

Please note: whereas these containers can be used with all G3 and G4 cameras without "Enhanced Cooling", they only fit to G2 cameras revision 4 or higher, which were delivered from early 2016 onwards. Older G2 cameras are not compatible!