Going big in my world

[Cameron Payne]

AR102/1000 is my cannon.Going BIG next to AR152s/760 Triplet with Flattener,I think someone else has the pleasure of said item?

Was going to go for Brassers long AR152s but it’s a Doublet like my AR102 so may aswell have a Triplet for not so many extra ££’s

A question.I’ve found the joys of lower power eyepieces with more glass,just can’t hack squinting high power jobs for especially Lunar.Considering my best cannon will be a  760mm fL,I’d like to go 2” so what’s the widest FOV degrees that best suits a 760mm tube?

Thanks in advance people.

[Stu]

1 hour ago, Cameron Payne said:

AR102/1000 is my cannon.Going BIG next to AR152s/760 Triplet with Flattener,I think someone else has the pleasure of said item?

Was going to go for Brassers long AR152s but it’s a Doublet like my AR102 so may aswell have a Triplet for not so many extra ££’s

A question.I’ve found the joys of lower power eyepieces with more glass,just can’t hack squinting high power jobs for especially Lunar.Considering my best cannon will be a  760mm fL,I’d like to go 2” so what’s the widest FOV degrees that best suits a 760mm tube?

Thanks in advance people.

Just bear in mind that the AR152s is still an achromatic scope, despite being a quadruplet design as far as I’m aware. I think it is a standard achro doublet at the front with a petzval reducer flattener at the rear to shorten the focal length and flatten the field. It will still show plenty of chromatic abberation though at higher powers and on bright objects like the Moon and Venus, just wanted you to be aware of that in case you weren’t.

2” eyepieces are worth it for low power, widefield views, but 1.25” are fine fire the shorter focal lengths; there is no benefit to the 2” format below around 16 or 17mm say.

What sort of budget do you have? For wider fields, the 20mm APM XWA 100 degree is highly rated, as is the 30mm 82 degree Explore Scientific. You’ll need a 2” diagonal too obviously if you don’t already have one.

[Cameron Payne]

Hey thanks for getting back.Clear this up for me…is the AR152/760 a triplet? with a flattener? Brasser themselves say that their AR152/1200 is their top refractor throw it’s a duplex and not a Triplet

[Cameron Payne]

I’m really only interested in Lunar and planetary observations 

[John]

I think the Bresser 152S / 760mm has a 4 element optical system. An F/10 achromatic doublet at the front end and a two element corrector further down the tube. There has been some argument over the years as to whether the design is a true Petzval type or not but it's along those lines. So pretty much as @Stu says.

I believe the colour correction is similar to one of the F/8 doublet achromats so still plenty of false colour but less than a doublet F/5 would show. The field is flatter with the quad design. They are quite heavy scopes and will require a stouter mount than your current AR 102 / 1000.

If the prime interest is in lunar and planetary observation there might be better options ?

 

 

Edited September 1, 2021 by John

[Stu]

1 minute ago, John said:

I think the Bresser 152S / 760mm has a 4 element optical system. An F/10 achromatic doublet at the front end and a two element corrector further down the tube. There has been some argument over the years as to whether the design is a true Petzval type or not but it's along those lines.

I believe the colour correction is similar to one of the F/8 doublet achromats so still plenty of false colour but less than a doublet F/5 would show. The field is flatter with the quad design. They are quite heavy scopes and will require a stouter mount than your current AR 102 / 1000.

If the prime interest is in lunar and planetary observation there might be better options ?

 

 

Yes, that’s my understanding John. None of the descriptions on line are particularly clear, but I believe it’s a Petzval type design ie achro doublet up front and reducer flattener at the rear.

I agree that if @Cameron Payne’s main interest is lunar and planetary then there are better options. Perhaps one of the Stellar Lyra classical Cassegrains, or a 150mm Mak?

https://www.firstlightoptics.com/stellalyra-telescopes/stellalyra-6-f12-m-crf-classical-cassegrain-telescope-ota.html

[johninderby]

The Opticstar version.

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_245

And the manual.

http://www.opticstar.com/Download/Astro/Doc/Telescopes/Opticstar/Opticstar-ARC152S-QUAD-OTA.pdf

[johninderby]

21 minutes ago, Stu said:

Yes, that’s my understanding John. None of the descriptions on line are particularly clear, but I believe it’s a Petzval type design ie achro doublet up front and reducer flattener at the rear.

I agree that if @Cameron Payne’s main interest is lunar and planetary then there are better options. Perhaps one of the Stellar Lyra classical Cassegrains, or a 150mm Mak?

https://www.firstlightoptics.com/stellalyra-telescopes/stellalyra-6-f12-m-crf-classical-cassegrain-telescope-ota.html

Having owned a Slymax150 and now having the StellaLyra CC6” find the performance is similar although would give the edge in on axis sharpnes to the CC. My grab’n’go setup on a manual alt-az setup. No dewing and very quick cooldown are the particularly nice features. Mine’s for visual but for AP the fixed primary and crayford focuser are useful. And a Baader Steetrack RT focuser is a nice upgrade. 🙂