Telescopes that are to be left outside the house or garage permanently ideally should be stored in an observatory building. However, for continuous 24/7/365 outside exposure protection where no observatory building is available, the TeleGizmos Series 365 Series covers are recommended. Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. As mentioned above, I personally own the largest version of this cover and use it for my Celestron Advanced VX 9.25″ SCT. It’s been great.

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope. We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value. TGN8: For GEM mounted scopes up to 46" long and 13" diameter, 57" major height - LXD55/75 SN10, SN8 with Dew Shield For refractor telescopes, the length is going to be very close to the telescope’s focal length so just knowing that will tell you if the cover will fit. The TeleGizmos Telescope Cover is a multi-layer, polyethylene material with a fully aluminized surface. The heat reflective ability of the cover is extremely high with a material strength equal to a multi-layer light weight tarp. The material used for Telegizmos Covers was originally developed for NASA as an insulator in spacecraft. It is very strong, light, tear and puncture resistant and is highly superior to Mylar in durability.Orion's telescope and astrophotography accessories will enhance your telescope enjoyment without breaking the bank. Expand your viewing experience with accessories ranging from moon filters to power-boosting Barlow lenses to advanced computerized telescope mounts. Capture breathtaking photos with our affordable astrophotography cameras. And when you're stargazing, Orion's telescope cases and covers, observing gear, red LED flashlights, astronomy books and star charts will make your observing sessions more convenient, comfortable and meaningful. I’d say yes. If you have already invested hundreds or even thousands of dollars into a telescope, spending a small fraction of that to keep it safe is worth the money. A dust cover by Astrozap is a great idea for keeping dust off your RC telescope. The sewn-in elastic band fits perfectly over the end of your telescope tube, preventing dust from settling on your optics and degrading image quality.

A good cover must be waterproof and impermeable. Even if you will keep the telescope indoors, there are always the occasional drops flying through the window or worse, unidentified moisture or leaks. We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. You can also find a telescope cover for specific telescope builds such as 12-inch Schmidt-Cassegrain telescopes on alt-az mounts , 5- to 6-inch Equatorian Refractors, and 10- to 12-inch f/5 Newtonians on German Equatorial Mounts. Buy a tripod coverto protect the legs of your stand from rust, dust, and UV radiation, or get a Celestron telescope cover to match your Celestron rig. Your telescope will be stored for many more hours than it will be in use, and you want to keep your optics clean and free of dust. Closing the tube will also prevent mice, cats, spiders and other things from nesting in your tube (all of which we have seen photos of!). However, if your tube has just come in from a dewy observing session, it should be allowed to dry out before it is closed up – put your dust caps on the next morning, assuming it has dried up by then. For its price, this cover is still fully featured and it even has side zippers in case for some reason you want to use your telescope directly under bad weather. I don’t really like the idea of testing the limits of the cover or your scope under the rain, but if you are more adventurous than me, it’s a useful feature to have.The only special case here is Dobsonians that due to their shape require a cover with a different design than the rest, but there are covers specially made to fit them. The silver coating you will see in high-quality covers serves two purposes. It reflects UV rays to keep them away from the mirrors, and is thermally stable, meaning it prevents the interior and the telescope from heating up. You don’t want your telescope exposed to too much heat because this weakens the optics glue, messing up the mirror/lens alignment, and it makes it so you have to wait longer for the telescope to acclimate to the weather every time you use it to get proper views. Are telescope covers worth the money? It comes in two sizes, a 39″ (990mm), and a 59″ (1500mm). That is the length of the tube, so make sure to know the dimensions of your device before buying. The price difference is minimal though, so if you have doubts, just go with the bigger model. Originally developed for NASA as a spacecraft insulator, the aluminized multi-layer polyethylene TeleGizmos standard solar cover material is strong, light, tear and puncture resistant, and much more durable than Mylar. It is even washable. TeleGizmos covers consist of a polyethylene base layer, a reinforcing fiber mesh layer, a layer of pure reflective aluminum, and another layer of clear polyethylene with double lap sewn seams for strength. Each cover has a material strength equal to that of a multi-layer lightweight tarp. The aluminized surface reflects away the sun's energy to keep your scope cooler in the daytime. It is waterproof to keep condensation from building up on your scope at night. It stays flexible at temperatures well below freezing and is unaffected by summer sun and heat. The bag-like scope cover fastens securely to your scope by cinching up the built-in drawstring of the opening at the bottom of the cover. Orion binoculars are known for quality optics at a great price. We offer binoculars for every viewing interest, including astronomical binoculars, compact binoculars, waterproof binoculars, birding binoculars, and sport and hunting binoculars.

The other one is huge, and I would have thought would cover most telescope/mount combinations. It also comes in a more lightweight version. Here's a link to the larger one I found if anyone is interested. The only issue I have with this cover is the price. It is high. But is it worth it? well, I believe that really is up to you. Personally, I would only get it for a very expensive telescope, but if yours cost the same or slightly more than the cover then there are better ways to spend that money.Many thanks to all those have replied, you've all really come up trumps with lots of useful solutions. These covers have been tested in the harshest of environments and have proven to be extremely durable and resistant. While the cover is durable, don’t expect it to withstand a whole season outdoors. It’s not made for that and that’s just true for all telescope covers. They are not made so you can keep your telescope outside permanently, they are made for indoor use and maybe, just maybe so you can leave them out for a couple of days a year.

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. The specifications should tell you the maximum length the cover fits and then you only need to match it to the length of the tube of your telescope. The most important thing when looking for a cover is making sure it is going to fit your telescope comfortably. Astromania offers this cover in 3 different sizes, 23.8″, 30.1″, and 37.6″. The one linked below is the 30.1″ version that will fit telescopes of up to 1000mm in length and 203mm of aperture that will fit most hobbyist-level telescopes. Still, measure yours just to make sure before buying.

Since 1975 Orion Telescopes & Binoculars has been offering telescopes for sale direct to customers. Now an employee-owned company, we pride ourselves on an unswerving commitment to best quality products, value and unmatched customer care. Our 100% satisfaction guarantee says it all. It is true there’s nothing too special about telescope covers and an old sheet can still cover it from dust, but all the other features do make a difference long term, especially if you plan to keep it in a room with questionable conditions like a shed or the garage. The HABOPET cover also claims to be fully waterproof and UV-reflective. As for waterproof, it does look like it meets expectations, but for the reflectiveness, I have my doubts. The coating seems a bit thin and I found no mention of it being thermally stable anywhere in the specifications so I’m not sure it can keep the telescope cool under sunny weather.