Hello all, this is my very first post.
I am just returning to astronomy after a 20-year hiatus. My first telescopes all those years ago were an original ES Astroscan, a Meade ETX-90mm and a William Optics 66mm ZenithStar SD APO. I enjoyed them all at the time. I still have the ZenithStar which I put on a tabletop Dobsonian mount. Assume that I know a little more than nothing but not much more.
I recently bought two used scopes on Ebay, both ETX-80mm refractors and I gave one of them to my 12-year-old granddaughter. We intend to have our own star parties over facetime on our ipads.
I have a specific question which I have not found the answer to on Cloudy Nights so far. The question relates to filters for viewing NOT for astrophotography (I am going to walk before I run). The ETX-80 mm is an F/5 achromatic refractor as you all know. I live in the Windsor-Detroit area and generally the skies would be classified as an 8 on the Bortle scale. My question is: What would be the best single or stacked 1.25-inch filters for my F/5 scope in my Bortle 8 backyard (for general viewing)? I intend to mount the filter(s) on my diagonal.
Your help is much appreciated.
I have an ETX-80. My first scope 7 years ago. I have 4 others but I will keep it for ourtreach events.
If most of the street lights have been switched over to white LEDs, then light pollution filters will be fairly ineffective.
You don't need any filters for that scope for general use. If you find the Moon too bright then perhaps a 25% Moon filter. I have one from Orion that I like very much. I use it on the ETX 80 and all of my other scopes. Also useful on Venus.
A nebula filter will come in handy for observing certain bright nebula, but not all. The DGM NPB is the one I use BUT not on the ETX 80. Using an 80 mm aperture it is only likely to be useful on very bright nebula, like the Orion Nebula. I have used it on my 125, 203 and 305 mm scopes. I don't think I ever used it on my ETX 80. It works better on scopes with larger apertures.
Orioin UltraBlock also has a good reputation but still, I am not sure how well it will serve you on an 80 mm.
I have played with colored filters with the ETX 80 but have not felt they were very useful. They were more effective on my 8" and 12". The 82a is worth a try. I occasionally use it with my 102 and larger but not on the 80.
My suggestion is to use the ETX 80 without filters, again, except perhaps a Moon filter.
The key to success with that scope, especially under Bortel 8 sky (same as mine) is to properly pick your targets
Galaxies and most nebula will not be good targets unless you can get to a very dark location, Bortel 4 or better would be my suggestion.
Moon, planets, stars, open star clusters, brighter globular star clusters, easier double stars would be your best targets. Plan to stay under 120X. If the seeing is really good you might be able to push 150X on the Moon, Jupiter and Saturn. That gives you thousands of targets to go after.
You can also put a solar filter across the aperture and observe the Sun.
The GoTo works well for me.
Edited by aeajr, 07 December 2022 - 08:02 PM.