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I try to design the best possible devices. However, when using them you may encounter various problems, most of which are quite easy to identify. This page was created to answer the most common questions that arise in connection with Astrodevice designs and finished devices. I want you to be as happy as possible with the product you get, so before you start making it yourself or before you buy a finished solution, please read the information below to be aware of the different technical aspects you may encounter when using Astrodevice solutions.

Main causes of technical issues

There are five main possible causes for technical problems:

  • incorrect manufacturing of the device
  • improper use of the device
  • operation at or below the dimensional tolerance limit
  • damage to the equipment
  • design errors

Incorrect manufacturing means that you downloaded the project files, printed the parts, assembled the whole thing but in the meantime you made a mistake somewhere. You may have not followed the technical instructions (e.g. used wrong layer heights or extrusion ratio), made a mistake in printing, used wet filament, etc. The result may be a recalibrated device with incorrect dimensions, resulting in, for example, a bad image or inability to screw in thread filters.

Solution: Carefully read all the technical documentation that comes with the project. Every sentence there has meaning and sense, so don’t skip anything. Never take shortcuts and don’t rush. If you use external 3D printing services, choose good contractors and don’t go for the lowest price. Good printing with good material has a cost. Give the company that is going to do the printing for you all the technical documentation. If threads are present in the design, leave the fittings, filters, etc. with the printing company so they can check after printing to make sure they screw in properly. It is also a good idea for you to read the Quality and Usage information that applies to our finished products. If you are buying accessories from Astrodevice, this page will give you an idea of what I consider to be the norm, the correct state of matter, and what you should and should not expect. This will be especially useful for people who don’t have frequent contact with 3D printing technology.

Improper use of the device means that the problem is due to the user’s work. If you are experiencing this class of problem, you may have put the device on incorrectly or crookedly. If the issue involves the filter drawer, for example, you may have over-tightened the threads, resulting in image distortion. You may have also stored the accessory in too high a temperature (e.g. in full sun in a parked car), which may have resulted in deformation of the device.

Solution: Some of these problems can be corrected if they do not involve permanent damage. Follow the technical documentation and if in doubt, contact me. I will try to help you identify and solve the usage problem.

Working at or below the dimensional tolerance limit. Every production technology has its own dimensional accuracy. You can make devices very precisely, but they will never be mathematically perfect. Also, every problem in the physical world requires a solution within a given tolerance range. You cannot perform precise neurosurgery with a hammer or drive nails with a precise, lightweight scalpel. The required resolution of the problem and the resolution of the tool must match. Astrophotographic equipment often requires very high accuracy. For example, in Celestron’s RASA 8 telescopes, the manufacturer expects backfocus accuracy of a hundredth of a millimeter, which is physically impossible to meet when using FDM 3D printing technology, which has accuracy to a tenth of a millimeter. Therefore, if you are working close to the limit of technological accuracy, you may encounter problems that prove to be very difficult to solve.

Solution: in this class of problems it is difficult to find a good solution. You should either refrain from working at the dimensional tolerance limit or accept the consequences that come with it. This means, for example, that in the case of my filter drawers you have to be able to accept the distortion of the stars caused by the micro-skew at the edges of the image. However, if you are expecting a perfect image – don’t use Astrodevice.

Damage to the equipment. Because Astrodevice’s main technology is 3D printing from plastic, the products are not as durable and resistant to failure as metal products. Even if they are reinforced with carbon fiber. They must be handled carefully and slowly so as not to damage them. When using threads, be careful not to damage them. Properly used, Astrodevice can be a lot of fun, and should last a long time and produce beautiful results, but for this, one thing is important: be careful and gentle. Do not do anything by force.

Solution: If you have damaged your device, in most situations you can print a replacement part using the free design database.

Design errors. Not only can the contractor, user, and work context be guilty of the problem, but also the designer. Even though I do my best to check my designs, it may turn out that I made a mistake somewhere. This is one of the reasons why I make all my designs available for free, so that everyone can check my concept before they decide to go into production. I urge everyone to read all the technical documentation and STL files before deciding to manufacture or buy the finished device.

Solution: If you find a design error, please let me know. I will try to fix it as soon as possible and provide you with a corrected version.

Questions about specific products

» Filter drawers and other camera adapters

1. Why is the shape of the stars in the corners egg-shaped?

As for the shape of the stars, physically this effect is caused by tilt, which is the skewing of the sensor plane. I have written an article on this topic, trying to explain the whole issue in detail. In this regard, another article you might be interested in is the one about results and experiments.

The question that arises is where does the tilt come from? There may be many reasons (as I described in the first mentioned article), but the most prosaic is the way the drawer is mounted to the telescope. Statically, the biggest influence is the strength of thread tightening. We have here a large sensor, a heavy camera which tends to fall down, held on a fine thread and the drawer itself, asymmetrical in construction (it has a notch for the slider) is made in a technology with manufacturing tolerance of a few hundredths of a millimeter. Additionally, in the M42 version we have to rely on centering the camera axis with the use of factory adapters attached to the telescope, which is often a problem. To a large extent, tilt problems can be eliminated by using a more robust camera mount and perfect centering, thus the M87 version. I have described the differences here.

My advice would be: first of all check the thread pressure. Very often this is the main cause of the problem. If you tighten the thread just a little too much, the problem occurs. Such is the beauty of RASA. I have described all this in my articles. Before you start an astrophotographic session, take one test photo, loosen the thread, turn it again with a little less force, then with a little more force and compare the results. Certainly the thread should not be tightened by force. You can also try to rotate the drawer so that the inlet on the slider is in a different place. Then compare the results. Also point the camera at different areas of the sky to see if you have to deal with the camera falling down (then, depending on where the physical bottom of the camera is, the location of the distortion in the image will differ).

To some extent, image distortion is unavoidable, at least with my designs and 3D printing technology. These imperfections come at the expense of the convenience and accessibility that my drawers provide. For this reason, try to follow the advice above, but also read another article regarding the quality of the resulting image. If you are in a situation where you are yet to make a drawer or buy a finished product, you should accept that the image you get will probably not be perfectly ideal in each corner of the image; especially for a camera with a large sensor.

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