Bresser Pollux 150/1400 vs SW 114/900 (is it possible to get rid of the integrated barlow?)

[Raph-in-the-sky]

Hello,

I'm trying to get a cheap scope for when I spend time at my in-laws in Valencia.

On local second hand websites, I see a lot of either Bresser or Seben 150/1400. Those scopes have an integrated barlow which is supposed to be really bad. My question is: for the same price, would you rather go for a classic 114/900 (or 114/500) or 130/900 or would you put more importance on apperture and get the 150/1400 despite the integrated barlow.

Also do you think it would be possible to get rid of the integrated Barlow? Will I still be able to reach focus?

Has anyone already use one of those scopes with integrated barlow? Is it as bad as people make it to be?

Cheers,

Raphael

 

 

 

 

 

[Cornelius Varley]

8 minutes ago, Raph-in-the-sky said:

Hello,

I'm trying to get a cheap scope for when I spend time at my in-laws in Valencia.

On local second hand websites, I see a lot of either Bresser or Seben 150/1400. Those scopes have an integrated barlow which is supposed to be really bad. My question is: for the same price, would you rather go for a classic 114/900 (or 114/500) or 130/900 or would you put more importance on apperture and get the 150/1400 despite the integrated barlow.

Also do you think it would be possible to get rid of the integrated Barlow? Will I still be able to reach focus?

Has anyone already use one of those scopes with integrated barlow? Is it as bad as people make it to be?

Cheers,

Raphael

The "barlow" is an integral part of the optical system in these Jones-Bird telescopes. The lens has two purposes,  the first is to correct the aberrations from the  spherical mirror and the second is to correct the focal length and achieve focus. Without the corrector lthe telescope will be even worse.

[Raph-in-the-sky]

22 minutes ago, Cornelius Varley said:

The "barlow" is an integral part of the optical system in these Jones-Bird telescopes. The lens has two purposes,  the first is to correct the aberrations from the  spherical mirror and the second is to correct the focal length and achieve focus. Without the corrector lthe telescope will be even worse.

Have you used one of these? Are they that bad? Would you go for this and get a 150 apperture or gor for a 114/900 for example?

[Cornelius Varley]

Its just a bad optical design. The spherical primary mirror is cheaper to make than the better parabolic primary found in classic Newtonians. The 114/900 also has a spherical primary, but at this size, a spherical mirror is not so much of a problem. I would avoid a 150/1400 Jones-Bird no matter whose name was on it.

[Victor Boesen]

I had the Pollux as my first telescope so I think I can add to this discussion.

As mentioned by the others, it's a Bird-Jones type of telescope which consists of a spherical mirror and a correcting lens. Without the correcting lens the telescope would work and it's, therefor, not possible to remove. I was happy with my Pollux for about a year until I started to get picky about its optical performance. Having a focal length of 1400mm it isn't that suitable for wide field either.

I remember observing Jupiter, Saturn and Mars through it back in 2015 or 16 and I noticed the rings on Saturn weren't as sharp as I have later observed them. The two main cloud bands were visible on Jupiter together with the great red spot. I don't ever recall observing an eclipse on its surface though. No detail was visible on Mars...

I later upgraded to a 10" dobsonian from Skywatcher, and I noticed that the rings on Saturn were sharper, banding was visible together with the Cassini division. I've observed numerous shadow transits on Jupiter, and the shadow is quite easily visible. Mars also shows albedo features, polar caps and cloudiness/haze on the limb. I know a 10" is a lot larger than the Pollux and the 114/900 you mention, but I think I'd have chosen the 114 instead over the two if I were to start over, although a Heritage 130 would probably be my most recommended option.

I sold the dob not long ago, and I now own a 72mm Skywatcher ED refractor and a 102mm F/7 apo. With the 72mm I've resolved detail on the Martian disk at a size of 8-9 arc seconds at 90X and had the best views of Mars with my 102mm, which I got a couple months ago. My point is, despite comparing the Pollux to a 10" dob, I've still managed to get better planetary views with apertures of 72mm and 102mm. On deep sky the Pollux will win though.

Feel free to ask me more about the Pollux! I don't remember everything that I've observed with it, but I may be able to help anyways!

I just dug out an old video of some videos I took through the Pollux. It looks a little worse in the video than in person, but you can see the planetary performance is lacking...

And here's a video of Mars with my 102mm refractor:
https://www.youtube.com/watch?v=oe7mw_s2uBc

 

Edited December 7, 2020 by Victor Boesen

[Raph-in-the-sky]

48 minutes ago, Victor Boesen said:

I had the Pollux as my first telescope so I think I can add to this discussion.

As mentioned by the others, it's a Bird-Jones type of telescope which consists of a spherical mirror and a correcting lens. Without the correcting lens the telescope would work and it's, therefor, not possible to remove. I was happy with my Pollux for about a year until I started to get picky about its optical performance. Having a focal length of 1400mm it isn't that suitable for wide field either.

I remember observing Jupiter, Saturn and Mars through it back in 2015 or 16 and I noticed the rings on Saturn weren't as sharp as I have later observed them. The two main cloud bands were visible on Jupiter together with the great red spot. I don't ever recall observing an eclipse on its surface though. No detail was visible on Mars...

I later upgraded to a 10" dobsonian from Skywatcher, and I noticed that the rings on Saturn were sharper, banding was visible together with the Cassini division. I've observed numerous shadow transits on Jupiter, and the shadow is quite easily visible. Mars also shows albedo features, polar caps and cloudiness/haze on the limb. I know a 10" is a lot larger than the Pollux and the 114/900 you mention, but I think I'd have chosen the 114 instead over the two if I were to start over, although a Heritage 130 would probably be my most recommended option.

I sold the dob not long ago, and I now own a 72mm Skywatcher ED refractor and a 102mm F/7 apo. With the 72mm I've resolved detail on the Martian disk at a size of 8-9 arc seconds at 90X and had the best views of Mars with my 102mm, which I got a couple months ago. My point is, despite comparing the Pollux to a 10" dob, I've still managed to get better planetary views with apertures of 72mm and 102mm. On deep sky the Pollux will win though.

Feel free to ask me more about the Pollux! I don't remember everything that I've observed with it, but I may be able to help anyways!

I just dug out an old video of some videos I took through the Pollux. It looks a little worse in the video than in person, but you can see the planetary performance is lacking...

 

Thanks a lot! That is very helpful. I currently have a SW 250/1200 as my main scope and I had a 130/900 EQ2 in the past so any of those would be a great reference point.

 

Regarding the Bresser, the one I might buy is an older version which is white... and I beleive shorter thus more corrected. To be honest, I found the pics of Jupiter trully awful (I'm not saying that to be mean, I trully appreciate your help). What did you use to take these pics? Is it a cell phone through one of these nice ES 82° EP? I 'll need to think about it but I may try to source a scope from another place (maybe a heritage 130) and have it shipped there as I can't find anything really satisfactory in the area.

[Mr Spock]

I had a Helios 150mm many years ago before I knew what they were. Contrast was very poor and Jupiter was a blank, featureless disc. Complete waste of money. I didn't think to sell it, I just scrapped it.

[michael.h.f.wilkinson]

The Bird-Jones design is not bad per se, but I have yet to see a good incarnation in the wild. I have heard Vixen made a decent one in the past. If you go for a 114 mm Newton, I would opt for the 900 mm focal length, at 500mm they often come with a spherical mirror: fine for wide field, but much less for planets. If you can stretch to a 6" F/8 Dobson, that will give you much better planetary views

[Victor Boesen]

5 minutes ago, Raph-in-the-sky said:

Thanks a lot! That is very helpful. I currently have a SW 250/1200 as my main scope and I had a 130/900 EQ2 in the past so any of those would be a great reference point.

 

Regarding the Bresser, the one I might buy is an older version which is white... and I beleive shorter thus more corrected. To be honest, I found the pics of Jupiter trully awful (I'm not saying that to be mean, I trully appreciate your help). What did you use to take these pics? Is it a cell phone through one of these nice ES 82° EP? I 'll need to think about it but I may try to source a scope from another place (maybe a heritage 130) and have it shipped there as I can't find anything really satisfactory in the area.

The white tube version will most likely be the same. I too find the Jupiter pics awful so no worries:) I took the pics with the supplied eyepieces (didn't have the 82 degrees at the time) and my iPhone 6 plus.

If you could find something like the heritage then I think you'd be more satisfied with it!

[Tiny Clanger]

I inherited a jones-bird type Celestron 114 eq,  and the j-b setup , internal barlow and spherical mirror gives a slightly soft image . It might not be something an uncritical beginner would notice at first, especially if they were just being impressed with their first sight of the Moon through a telescope, but after a while you notice it, and one fuzzy indistinct view of Jupiter is enough. Somewhere I have a photo of the Moon I took through the j-b , I'll try and find it and post it ... although I might well have deleted it  !

The sw 150 dob I then spent £200 on is a huge improvement in sharpness and contrast.

Heather

[Raph-in-the-sky]

Thanks for all the replies. I will stay away from those Jones-bird scopes and try to find a classic newtonian optical formula. 

Cheers,

 

Raph