3 replies to this topic

[Raydarnsky]

Newbie here, I just ordered a Celestron 6" Evolution and I live in Wyoming where it is a very dry climate.  I kind of know the answer to my question (dew shield is needed), the question is priority, should I get a dew shield immediately even before I try out telescope or can I wait for a while.   That leads to the next question, which dew shield should I get, celestron offers 3 different ones, or are there better options, and while I'm at it should I get a heater?  Thanks for easing my mind a little, I don't want to damage the telescope immediately if I can help it. 

[Notdarkenough]

Welcome to CN! I have the 8" version of your rig. I have found that the different dew shield types offer different pros and cons. The first concern is the wind profile. Most of Wyoming can be breezy or windy, consistently. The C6 is fairly wide, and adding a dew shield may cause instability under breezy conditions. This type of problem will show the mount's play in between the gears.

 

The second question is area lights nearby your observation location. A good dew shield can effectively block neighbors porch lights or maybe some nearby streetlights. The third is actual dew prevention. I am just next door, so I understand dry climes. In my experience, use a specific dew shield of dew prevention is it's least helpful use.

 

All that said, I have found what I like, with the Celestron Aluminum Dew Shield with metal dust cap. It is longer than normal, giving me excellent point-source light blocking. However, I don't have much wind in my area, and wind will use that aluminum shield like a sail. I also like the AstroZap FlexiShield. This offers the same kind of benefits but is less prone to wind instability. 

 

My recommendation is to try something different. Are you setting up your rig each night and then taking it apart afte each use? If so, one of the challenges with an SCT is temperature acclimation of the air inside the OTA. To combat this, you can insulate your OTA with something like a yoga mat, or flexible plastic material. This is much easier than it sounds! There are a large number of threads here on CN that discuss what materials you can use, and how to design the overlayment. When you do this, you can significantly decrease your temperature stabilization wait times, and extend the insulation so I can act as a dew shield as well. I think this is the way I would go in your position. 

 

In summary, share more about how you plan to use the rig, visually or some type of imaging.  And, share more about your local environment and it's challenges. Search Cloudy Nights for threads about "SCT Insulation Cloudy Nights" in Google. And, lastly, I highly recommend a book about owning and operating a NexStar Evolution system. It is written  by Michael Swanson, a fellow CN member, and is titled The NexStar User's Guide. He has a very helpful website ( https://www.nexstarsite.com/ ) where you can get tips and checklists and links to his book on Amazon or other sellers.

 

Lastly, the Evolution 6/8 rig is very common, so it should be easy to get help as you find things uncertain. The single best way to learn about your new gear resides in your community. Your local Astro Club has loads of experience and can provide in-person assistance as you learn. They can also offer different OTAs, eyepieces, diagonals, finders, etc... for use at Star Parties or Outreach events to broaden your general astronomy knowledge. Check out this website to help you find local resources. https://nightsky.jpl.nasa.gov/clubs/

[Raydarnsky]

Thanks Gemini for all the good information, I knew someone would be able to help.  Yes we do live in a very windy area and I had not considered that until your post.  Being a new user I will undoubtedly be moving the telescope in and out for observations, so that is a definite consideration (which I hadn't given any thought to as well....).  My  wife and I live in a fairly large home where we raised our family so we have two bedrooms that are not used much so we close the doors and keep them relatively cool, storing the telescope in them during the non use times may help reduce the temperature acclimation, sounds like insulation on the OTA would be a good idea.  I had already seen the book you mentioned and get one on order.  As far as local clubs, we live near Glenrock and I have searched for a local club online and at your suggested site and found nothing yet, maybe there are some local users I will be able to find and get intouch with them.  Now off to do some shopping and searching..  Thanks again Gemini!

[Peter B]

Hello Raydarnsky, I have an Evo 8 and don't use a dewshield. I have one but have never used it, mainly because I'm not out when there's a lot of dew action. Wind would definitely be an issue especially in Wyoming.