Replacing Dust Covers on My Dobsonian Telescope

Replacing Dust Covers on My Dobsonian Telescope

When I built my Dobsonian in October 2016, I purchase dust covers from Astrozap. I needed a solution to cover both ends of my homemade telescope from dust and light. If I recall seven years ago, there may have been other options, but the Astrozap covers seemed by far the best answer to keep the ends reasonably blanketed. A homemade solution was viable, but the Astrozap covers looked and operated nicer than anything I could have rigged myself.

When I use the Dobsonsian at night, both covers are removed from the telescope at least once. The bottom one is taken off so I can collimate the mirrors with with the bolts behind the primary mirror. I then immediately return the cover to the scope to block out excess light (and there is a lot of excess light). The top cover obviously must be removed to use the telescope, normally placed on an outside chair for the duration of the viewing or photography session.

Ove the past several months, I noticed the bands on the covers had become considerably loose. I then observed that the overall color and thread strength had faded as well. This is to be expected. They lasted over seven years and only started to exhibit wear over the past year. My main worry is that the bottom cover’s band would no longer have the tightness to remain attached to the tube. And so, I decided to look into replacement covers.

I kept an Excel file with inventory of all the parts I bought and ordered for the original build. In truth, I had forgotten where I bought the dust covers from, but thankfully the inventory file listed the items with Astrozap. I was pleasantly surprised then to find Astrozap still in business, and they still had the same covers available for sale! Here is the product I bought (times two) for my 254mm telescope:

There is not much by way of installation. Simply unpackage the new covers and replace them on the telescope after removing the old ones, taking care to avoid the procedure anywhere near sunliight.

It is difficult to appreciate the wear on the covers after seven years, but here is a photograph of the old and new covers next to each other. The older one is on the left, and you can see the fade, at least a little. The threads are much more pronounced on the new cover, and the band is much more taut, even if the photo does not convey that.

Finally, I composed a couple of before-and-after photos so you can see the old and new covers on the telescope. The covers on the top of the telescope are shown above as the title image for this article. The old cover is noticeably droopy, as well as the bottom old cover, shown here on the left:

Old dust cover (left) and new dust cover (right) from Astrozap.

If you have any questions about the dust covers, please let me know in the comments below.

And by the way, it is well past time for me to clean the primary mirror. A task for 2024!

Thank you for taking the time to read my article.



I write frequently about astrophotography, technology advice, and my other interests like science fiction. I have over 30 years of experience in computer programming, information technology, and project management.

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