AZ-GTI

[Stu1smartcookie]

yep seeing is doing ... i just meant that to DO is to image and then process .. whereas looking is , well , looking .

 

[MarkAR]

Well enjoy your future as an astronomer and get as big a Dob as you can.

[Stu1smartcookie]

ok So heres a little update ... i bought my dob ... a 10" bresser ... oh wow , what a scope ! but , and here's the surprise , i was able to change my Az-GTi with another one and low and behold this one is doesnt slip ... i am now on the look out for a very short tube refractor ... the bresser 102(460) is in the frame as its such a compact and light scope . I want to use it for wide field,  and portability is the key here . It says in the blurb that it has ED glass but the only reviews i see are in german lol . ... i actually really like the bresser stuff , although i could be tempted with an ED 72 from skywatcher . Any thoughts on these two ?

[Dr Strange]

The Bresser is a fast scope at f/5.9. So is the Skywatcher. That will mean that you will have chromatic aberration (CA) issues on bright objects like planets and bright stars. That means a purple or yellow haze around the object. How much this will bother you depends on how sensitive to CA you are. I am very sensitive to CA and it drives me to distraction. So Achromatic telescopes are not an option for me. The ED element will attenuate this issue somewhat but not by much. 

A better option would be the 120 Evostar by Skywatcher. It is much slower at f/8. I have looked through The Explore Scientific version of the Bresser and the 120 Evostar. The ES 102 had a significant amount of CA in it on bright objects. The 120 didn't have anywhere near as much. The 120 is a the top of the weight and moment arm capabilities of the AZ-GTi but it can handle it. I use my Tele Vue NP101is on my AZ-GTi. It is 5.4kg. There are shakes that settle in under a second with it but I expected that going in and am OK with it.

Another thing to consider is that for visual quality (note I said quality meaning the best you can get) aperture is important. A 102 is nice but when you get into the 120 class it is an entirely different experience. In general quality being the same every 20ish mm of aperture increase is a big step in a refractor up to about 150mm. After 150 it gets stupid expensive, stupid heavy, and stupid big. 120-130 is considered the "sweet spot" for a refractor. 

[Stu1smartcookie]

21 hours ago, Dr Strange said:

The Bresser is a fast scope at f/5.9. So is the Skywatcher. That will mean that you will have chromatic aberration (CA) issues on bright objects like planets and bright stars. That means a purple or yellow haze around the object. How much this will bother you depends on how sensitive to CA you are. I am very sensitive to CA and it drives me to distraction. So Achromatic telescopes are not an option for me. The ED element will attenuate this issue somewhat but not by much. 

A better option would be the 120 Evostar by Skywatcher. It is much slower at f/8. I have looked through The Explore Scientific version of the Bresser and the 120 Evostar. The ES 102 had a significant amount of CA in it on bright objects. The 120 didn't have anywhere near as much. The 120 is a the top of the weight and moment arm capabilities of the AZ-GTi but it can handle it. I use my Tele Vue NP101is on my AZ-GTi. It is 5.4kg. There are shakes that settle in under a second with it but I expected that going in and am OK with it.

Another thing to consider is that for visual quality (note I said quality meaning the best you can get) aperture is important. A 102 is nice but when you get into the 120 class it is an entirely different experience. In general quality being the same every 20ish mm of aperture increase is a big step in a refractor up to about 150mm. After 150 it gets stupid expensive, stupid heavy, and stupid big. 120-130 is considered the "sweet spot" for a refractor. 

Many thanks for the reply , i was considering a 120 but i thought it would be a bit on the heavy side , especially when i put a camera on it . I have made a purchase of the little Bresser , i have the option of returning it if i want , which takes all the pressure off . The jury is out whether this little scope has ED glass but i suppose the proof will be in the pudding on that one . Im a bit smitten on bresser stuff at the moment , apart from the attrocious finder and average lens they supply wth their scopes ( why do they do that ?) the actual OTA are built very well . From what i have read longer focal length scopes seem to cope better with CA . My tripod can carry 8kg although it looks like it could be blown over by someone sneezing , so i am mindful of keeping weight down . This scope will be used for wide field , and taking a few snaps , ive got the dob for planatary stuff (when they finally get visible at a reasonable time ... cant wait for the autumn ) , so im not too worried about the CA . Of course i will look at stuff like that , but i not expecting too much . 

[sputniksteve]

On 10/05/2020 at 14:04, ScouseSpaceCadet said:

artificially recreate something that's been done before

 

Burn!