Apo's ???

hi,

Just thinking about Apo's and what they are best at verses other types of scopes


Astrophotography espicially wide field ... none better

Planetary/Lunar Observing ...excellent but a MakCas or MakNew of 1" larger arpertue will do as well for less money.

Doubles .. ditto above

Deep Sky... Achro's do as well, and Newts and Sct's do better for less money

So the question is why is there so much Apo fever around ?


Clear Skies,

Larry Citro

Ok, but which one of you is going to buy the new TV 5" APO?
I want a complete report on it by next week please! ;^)
Floyd

I am generally a fan of newtonian scopes (Have a 10", just sold an 18", getting a 14.5"). I also just got an ED-80 (I'm not going to argue whether or not it's a "true" apo....). The reasons I was interested in a small apo were to get a single scope for quick looks and/or travel that could do both wide fields and planets well. Maksutov's do planets well, but can't do wide fields. Achro's do wide fields well, but aren't very good on the planets. small newts tend to be long f-ratio, and again can't do wide fields as well, and the few small fast newts around suffer from large relative secondary sizes.

I have an ETX-90 and ST-80 that I was using as my planetary and wide field scopes, respectively, but I wanted to get 1 scope that could do both. The ED-80 has the additional advantage of a very nice price point, but I was considering something like a used Genesis, Tak or Televue 78, etc. before the ED-80 came out. For quick cooldown, sharp and contrasty views at high power, and wide fields at low power, an APO is the only single scope that can do it all.

Once you get into the larger sizes, the APO starts to lose it's appeal to me except for astrophotography. My big newts have about the same setup time and weight as 6" APO on an equatorial mount, and will show more on both deep sky and planets than any 6". They do give up the wide field, but that's why I plop the 80mm down next to them.....

Jarad

So you have never looked thru one? The view has something magical about it. Stars are not blobs as in other types of scopes and the view is generally more contrast. There is also the factor of pride of ownership playing a role. It is a pleasure to use my NP101 every time it is outside. Vlad.

Inch for inch nothing gives a better view than a good APO.

Aesthetics: There's a brilliance and clarity to the view through an apo that other scopes can only approach.

Geek appeal: An apo combines sophisticated design and exotic materials to produce the maximum available performance per inch of aperture.

Reliability, Availability, Maintainability: Relatively fast cooldown, colimation interval in years or decades, never needs recoating, the last scope on the field to be dewed out.

Not necessarily in that order.

Larry
I have read reviews re Mak Newtons performances versus a 5 inch apo and compared them myself.
I have a 5.1 inch true apo. A friend had a 6 inch Mak Newt. I had the opportunity to compare on several occasions and took it.

On contrast I personally would out the 6 inch Mak Newt at more like a 4.5 inch refractor. The refractor revealeda tad better lunar and planetary detail easier in good seeing.

I recall craterlets appearing that were not seen in the MN plus other lunar detail and better belt detail on Jupiter in the refractor. More contrast per brightness.

On deeper sky and doubles the differences were smaller.

My brother has just got his hands on a 715 Rumak. Now that will be interesting to compare to say my 5.1 inch apo.

I wonder if anyone has seen a comparison between this scope(180 mm aperture and 24 % obstruction and a 6 or 7 inch Mak Newtonian?

Kevin B