I personally think way too much is being made of CA for a beginner's first telescope. Yes, there is a little CA on the planets, but to a beginner observing the Cassini Ring for the first time I doubt he'll even notice. It took me over 2 years observing the craters of the Moon before I even noticed the thin blue line. Virtually everything else in space shows no CA at all. Don't let perfect get in the way of the good.
Portable telescope for urban astronomy
Posted 03 March 2021 - 07:22 AM
Without ED, a short achromat can be very portable and useful for my criteria. But I am not sure how annoying the chromatic abberation will be due to the short f ratio. Maybe the CA could be reduced with some filters?
In general, chromatic aberration is only a problem when observing the Moon and planets. And even then, it just means that you will see colored fringes around the object (only really obvious on the Moon and Venus) and mildly reduced detail.
For the record, my current favorite rig for carrying long distances on foot is an 80-mm f/4.4 achromat on a photo tripod. It's deliciously easy to stuff scope, eyepieces, and tripod into a pack that's not even terribly big. No, the views cannot match a 130-mm Newtonian. But they're still pretty great.
- Jim Haley, PNW and Black bird like this
Posted 04 March 2021 - 04:14 PM
I live in an apartment in the middle of Germany in a city with around 150.000 people. The sky is bortle 5-6. Thankfully, I can use the buildings roof terrace which gives me a good view to the south. But there are other apartments all around with disturbing lights. The terrace is two floors over my apartment, so the telescope needs to be portable to get it up the stairs. Additionally, it should be easy to set it up and not to bulky to store it easily. Since I have no car it would be perfect to take it to darker places out of the city by foot.
If you can find a way to avoid direct view of lights your eyes will show you a lot more, even in the city skies - maybe a "monks hood" would be a nice addition to your kit https://r-sky.org/en.../observing-hood
- radiofm74 likes this
Posted 04 March 2021 - 04:46 PM
I have a MAK C127 and it is the perfect Lunar scope. But I have no stairs to climb. It is not lightweight.
To me the best answer is one of my most used scopes: The AT60ED. With binoviewers, with a nice Zoom and barlow, it does just about every thing I need it to do in the solar system. I ride it on an Orion astronomy tripod. The OTA is the size of a water bottle. I can, literally, carry the whole set up in one hand, without much effort at all.
Ideal for the city. It's what I use, and I'm in a city!
- jcj380, VaGo and Black bird like this