Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

New - comparison of two telescopes

  • Please log in to reply
12 replies to this topic

#1 present

present

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 10 Sep 2019

Posted 10 September 2019 - 07:50 AM

Hi,

I'm new to this forum and overall new to this field - indeed thrilled to get started.

I wanted your opinion about two telescopes that are my (currently) final choices - either the Skywatcher Heritage 130P or the Bresser 130 DOB (couldn't find much information regarding this one).

I'm leaning towards the Heritage due to its positive reviews and cheaper price, though it's quite a challenge to find this one where I live (Israel) and ordering it online will cost more than the Bresser.

Is there much difference between the two?

Thank you in advance.



#2 SteveG

SteveG

    Cosmos

  • *****
  • Posts: 7729
  • Joined: 27 Sep 2006
  • Loc: Seattle, WA

Posted 10 September 2019 - 12:19 PM

They are likely equipped with the same optics. Your choice would depend on your portability needs. The collapsing tube Heratige is the same as the AWB OneSky, and the Bresser is the same as the Z130. If you don’t need the extreme portability, the the solid tube Bresser is your choice, with its rack and pinion focuser and tube rings.


  • vtornado and mrsjeff like this

#3 alexantos

alexantos

    Vostok 1

  • -----
  • Posts: 122
  • Joined: 05 Jan 2019
  • Loc: Estoril, PT (White Zone)

Posted 10 September 2019 - 04:55 PM

Check out this sale item on the Bresser shop. It's a 6" tabletop Newtonian with 89€ discount.

The only issue is the 50€ Shipping cost. Nevertheless you save 39€...

 

I have a similar 8" tube on a Dobson mount, and I can tell you that the optics are exceptional and the focuser is very precise. Also the red dot finder is very practical and easy to use.

 

Early this year I've posted a topic seeking advice, like you, to buy a scope. I also started asking about tabletop Newtonians but ended buying a Dobsonian. Check out the topic and maybe you'll find something useful for you in there.

 

Take care.


  • Cames and mrsjeff like this

#4 vtornado

vtornado

    Surveyor 1

  • *****
  • Posts: 1959
  • Joined: 22 Jan 2016
  • Loc: Northern Illinois

Posted 10 September 2019 - 08:09 PM

I second what Steve said, I have the bushnell aries 5 which is the same as the heritage.

 

The heritage collapses which is nice, but the Z130 has a R&P focuser and rings which will allow you to rotate the focuser to a position you like,

and it could help with balancing too. it also has a vixen finder shoe so you could ad an optical finder if you would like.

 

I have noticed my aries 5 changes collimation each time I use it, because of the trusses.  Not a problem a 30 second tweak with

a cheap laser an a barlow fixes it.  The solid tube will hold collimation better.


Edited by vtornado, 10 September 2019 - 08:09 PM.

  • SteveG likes this

#5 present

present

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 10 Sep 2019

Posted 11 September 2019 - 08:02 AM

Thank you all for the information.
By the way, is a dobsonian scope significantly better than the table scope?

#6 SeaBee1

SeaBee1

    Soyuz

  • *****
  • Posts: 3810
  • Joined: 19 Mar 2015
  • Loc: Under the DFW light barrier

Posted 11 September 2019 - 08:13 AM

Thank you all for the information.
By the way, is a dobsonian scope significantly better than the table scope?

 

The Dob mounted scope is an all in one setup. Scope, mount, done. Very stable. A table top scope, on the other hand, requires you to put the scope/mount on something... like a table! And you need a very stable table to make it work well. The Dobs referred to by others also offer a bit more aperture as well.

 

The advantage of the table top scope is portability... until you figure in the table...

 

So, yes, the Dob mounted scope will be better in the long run.

 

Good hunting!

 

CB



#7 present

present

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 10 Sep 2019

Posted 11 September 2019 - 08:45 AM

Thanks for the explanation.


Edited by present, 11 September 2019 - 08:46 AM.


#8 vtornado

vtornado

    Surveyor 1

  • *****
  • Posts: 1959
  • Joined: 22 Jan 2016
  • Loc: Northern Illinois

Posted 11 September 2019 - 02:51 PM

The "table" for a Z130 does not have to be that sturdy, it is a light scope, and it is small aperture,

so I don't normally exceed 150x.

 

I use a 6 gallon paint bucket on a lawn, I can track easy, better than a refractor on an alt-az mount

Of course if the ground you are on is highly sloped, or really bumpy a bucket wont work, you will have to use a 3

legged stand.

 

Some other ideas are a plastic milk crate,  plastic picnic coffee table, I have heard some use the hood of their car.

A wood picnic table like in a park will work, except if it has attached benches you can't sit on the same table.

 

Sometimes I sit on the ground with the scope on a blanket,  I have a grass allergy,

so I don't like to touch grass, you may not even need the blanket.

 

That being said there are some tables that don't work.  I have a small iron patio table that sways and vibrates.

 

========

 

A "table top"  and a dobsonian are both dobsonians.  What makes a dobsonion a dobsoian is

it is reflector telescope, and the mount is a box that sits on the ground.  As opposed to a tripod.

The difference between the table tob and regular is that a regular dob has a long focal length so when the

telescope is set on the ground the eyepiece is at a height that is comfortable for most adults to view.

Table tops are short focal length scopes where the eyepiece is too low to set the scope on the ground and view.

(unless you are sitting on the ground).


Edited by vtornado, 11 September 2019 - 08:15 PM.


#9 Tony Flanders

Tony Flanders

    Hubble

  • *****
  • Posts: 16969
  • Joined: 18 May 2006
  • Loc: Cambridge, MA, USA

Posted 12 September 2019 - 05:01 AM

Thank you all for the information.
By the way, is a dobsonian scope significantly better than the table scope?


This is really all about aperture. Arguably, a tabletop scope like the Heritage or Bresser 130 is a Dobsonian. The only difference is that with a traditional Dob, the tube is supported on both sides, whereas with a one-arm mount it's only supported on one side. From a pure engineering viewpoint, it's better to support the tube on both sides, so that everything remains in balance. With a one-arm mount, by contrast, the tube tends to bend the single arm over toward the telescope. But if the tube is small and light enough -- as with a 130-mm f/5 scope -- then this bending torque is small enough not to be a problem.

 

So single-arm supports work OK up to about 5 or 6 inches of aperture; beyond that it's definitely better to use a traditional Dobsonian box support.

 

The other issue is whether the base is placed directly on the ground or on some kind of support. This depends on the length of the tube, the length of your own body, and above all, whether you observe from a sitting or standing position.

 

People tend to place the smaller one-arm scopes on supports and the bigger Dobs directly on the ground, but there are plenty of exceptions in both directions. I have in fact used the AWB OneSky (a.k.a. Heritage 130P) with the base placed directly on the ground. It works quite well as long as you yourself sit directly on the ground. Conversely, the small minority who strongly prefer observing from a standing position often place traditional 8-inch f/6 Dobs on some kind of support. Otherwise, you end up doing a lot of crouching or kneeling, especially if you're tall.

 

But when all is said and done, your question really comes down to "are 8-inch scope better than 5-inch scopes," since for all practical purposes all 5-inchers are on one-arm supports, and all 8-inchers are on traditional Dobsonian two-sided box supports. And the answer to that question is easy.

 

Ignoring issues of portability (definitely) and ergonomics and low-power capability (maybe), 8-inch scopes are better than 5-inch scopes. Much better. That extra 3 inches moves you from being able to discern features on Jupiter with considerable effort to having them in your face and obvious. It moves you from being able to resolve individual stars in a handful of globular clusters under dark skies to being able to resolve individual stars in many globular clusters even under mediocre skies. And it moves you into the realm where you can see spiral arms within a fair number of galaxies if you are lucky enough to have genuinely dark skies.

 

As for portability, I own both a 130-mm f/5 on a fairly sturdy home-built table and a 7-inch f/5.4 Dob that always sits on the ground when I observe. Both scopes superb ergonomics, though the 130-mm is a tad better.

 

The 130-mm f5 plus its table are much easier to carry than the 7-incher with no table. And much easier to place in a car, since I designed the table so that the scope nests inside it when the table is upside-down.


  • SeaBee1 likes this

#10 present

present

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 10 Sep 2019

Posted 13 September 2019 - 06:55 AM

Valuable information from everyone. Much appreciated, thank you.



#11 aeajr

aeajr

    Voyager 1

  • *****
  • Posts: 12544
  • Joined: 26 Jun 2015
  • Loc: Long Island, New York, USA

Posted 14 September 2019 - 11:26 AM

Dobsonian refers to the mount. 

 

The tabletop scopes you asked about are on Dobsonian type mounts.  The optical tube assemblies on both are Newtonian reflectors.

 

Generally when you read Dob on this forum it is referring to a floor mounted AltAz mount that was designed by John Dobson.  It has become an industry standard mount.  But, as  you saw, there are tabletop versions too. 

 

Most, but not all, Dobs have a Newtonian reflector optical tube assembly on them.   So the floor mounted Dobs differ from the table mounted Dobs you asked about by aperture and focal length.   The floor mounted units have a longer focal length and usually, but not always, larger aperture. 

 

Different types of Telescopes
https://telescopicwa...-of-telescopes/



#12 present

present

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 10 Sep 2019

Posted 15 September 2019 - 01:16 PM

Thank you for the information. 

 

I'm thinking about getting the Sky-Watcher 8" Collapsible Dobsonian instead for its price and availability in my country. I have read tons of reviews about it, yet couldn't confidently decide if I should click the purchase button. 

What's your opinion about it?



#13 SteveG

SteveG

    Cosmos

  • *****
  • Posts: 7729
  • Joined: 27 Sep 2006
  • Loc: Seattle, WA

Posted 15 September 2019 - 03:56 PM

Thank you for the information. 

 

I'm thinking about getting the Sky-Watcher 8" Collapsible Dobsonian instead for its price and availability in my country. I have read tons of reviews about it, yet couldn't confidently decide if I should click the purchase button. 

What's your opinion about it?

All accounts I’ve read is that it is an excellent scope. This is a much better option than the table-top dob’s.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics