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. 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. Many thanks to all those have replied, you've all really come up trumps with lots of useful solutions. 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. 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.

The most important thing when looking for a cover is making sure it is going to fit your telescope comfortably. The inner liner radiant barrier provides radiant heat protection, effectively protecting your equipment from radiant heat build up. Additionally, as a second inner liner it provides additional protection from water penetration.

Celestron Case for 8 - 9.25" & 11" OTAs

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. 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.

A year of strenuous testing in some of the harshest outside environments, including the desert southwest, Florida Keys, Colorado @ 8000 feet and the Texas Hill country has proven the 365 Series to be capable of handling all types of weather on a continuous 24/7, 365 basis. 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. Orion offers telescopes for every level: Beginner, Intermediate, and Advanced. From our entry-level beginner telescopes for amateur astronomers to our Dobsonian telescopes to our most advanced Cassegrain telescopes and accessories, you can find the best telescope for you. Because we sell direct, we can offer you tremendous value at a great price. 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.

Telescope Cover

TeleGizmos 365 extended exposure covers - These use a multi-layer dual material design for extended-duration weatherproofing. They use the original TeleGizmos Solar Cover multi-layer material as an inner radiant barrier. This is coupled to an outer cover made of acrylic-coated high thread count woven polyester. This material is tested to prevent moisture penetration from a 1/2 inch concentrated water stream at 40 PSI, a heavier and more concentrated drenching than even the worst storm can provide. The inner Solar Cover liner provides radiant heat protection, effectively protecting your equipment from external radiant heat build up. It also provides an additional layer of protection against water penetration. 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. 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. The advantage of bags and cases is they take less space and reduce the risk of someone or something accidentally pushing it and potentially breaking something. 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.