Bird-Jones Problems?

[mattjanes100]

So, I'm still relatively new to practical astronomy and only got around to buying my first scope in the summer. I like to research anything I buy to the tiniest detail, so much so that my wife is surprised I ever get around to buying anything. But it seems my research missed an important piece of information here, that I seem to have purchased a bird-jones scope:

https://www.telescopehouse.com/bresser-reflector-pollux-6-150-1400-reflector-on-eq-2.html

So far I haven't experienced any particular problems with it but have read recently that this scope design will inherently result in poor views and longer term issues. Is this something I should be particularly worried about in the short term? Likelihood is a medium term plan to get this kit on ebay and pick up a replacement from FLO.

[Ruud]

Edited version:

Even if made of good quality components. Bird Jones Newtonians are difficult to collimate. There are Youtube videos showing how to go about this. We never recommend these telescopes. A simple parabolic Newtonian is a better choice.

 

Edited October 21, 2019 by Ruud

[rwilkey]

I think the biggest problem you will find is the EQ-2 mount and tripod, which could be a little unsteady, the other problem you will find is that they are difficult to collimate as there is a Barlow lens in the focuser, preventing a collimation tool from being properly inserted.  My advice is to make the most of this new toy and get some viewing experience in so that you will know where to go next.  Clear skies!

[vlaiv]

It looks like you already got one?

Nothing wrong with the design itself. It has certain characteristics much like any other design out there. With this design however, it proved that low cost implementations are plagued with poor execution of the design. Not the fault of the design but rather of manufacturing process and attention to detail.

Not sure what you mean by longer term issues. If it's not performing adequately - it will do so from the start. It will not suddenly or over some period of time start performing poorly on its own.

Since you already have it, and one could say you are in luck of not having much of experience so you won't be able to tell if it is poor optics straight away - just use it until you are ready to replace it. Do be careful however to blame things on the scope, as it might not be down to it, at least not everything will be down to it. There is seeing that can often be mistaken for poor optical quality, especially by novice observers (I'm guilty of that even after quite a bit of observing under my belt). Just use it in a way that is most pleasing - that gives the best image and as you progress in your observing skills it will be more apparent what is due to seeing and what is down to scope optics.

[mattjanes100]

Thanks all for quick responses! Yes, I do already own this scope and have been using it. As suggested perhaps best to let it serve it's purpose as a 'beginner' scope and upgrade in due course.

Luckily haven't had a need to collimate yet, but Robin is correct that the tripod is not of the highest quality.

[Victor Boesen]

I had the Pollux as my first scope at it was a fine scope for the money. The detail on the planets and the moon was the thing that was lacking the most. After I have upgraded to a 10" dob and now also owning a skywatcher evostar 72ed, the dob out performs the pollux by a long shot. Keep in mind this is 4" more of aperture, but I think the planet detail is a lot more consistent. The skywatcher frac also outperforms (surprisingly) the pollux on Saturn which is amazing considering the 3" less aperture.

If you have the money, sell the pollux and get a skywatcher dob, if you don't, don't worry and try to enjoy the scope while you have it.

Victor

EDIT: I reread my post and noticed that I was quite negative towards the scope. It's by no means a bad scope but after I had owned it for almost two years and I had observed through other telescopes, I started to notice it (small) flaw caused by the design.

Edited October 21, 2019 by Victor Boesen

[Gottzi]

My Skywatcher Skyhawk has the Bird Jones design but I love it. Never had any issues colimating or viewing. I'm sure ones day I'll upgrade but not thinking of it yet.

[Mr Spock]

I had an old Helios 150mm many years ago. Despite lots of CA, the 120mm Achro refractor I had (also helios) was far sharper.

[joe aguiar]

i dont think that type is horrible it always comes down to size weight and COST

i know where iam the bird jones 5" on eq2 is $239 before taxes ($270 with taxes)The other kind 5" f/5 with parabolic mirror is $70 more at $299 before taxes ($338 with taxes). The bird jones is only 18" long and 7 lbs so its very light and small. If you live in a condo apt and have to carry it out to the elevator and to the outside, a larger scope can get heavy fast when u carry whole mount scope and all. Now for some people $70 more then taxes can for some people put them out or over the budjet. I think its better to buy a 5" birds jones if this is your max budjet vs someone buying a 3" reflector then.

sure it will give u less clear images over 150x power and being only 7lbs and 18 iches long it can go on a eq2 mount easily the long version will be at their max weight.

so if you have it already use it and once u feel u done enough maybe then go 1 step up (dont sell that but get the parabolic version of the same size) like 6" reflector f/5 WITH a parabloic mirror then you will see a big difference.

 

joejaguar

 

[Alan64]

I have a 127/1000 "Bird Jones"...

It came with an EQ-1 mount, which is the very smallest equatorial on the planet.  Consequently, it will be mounted upon another of my mounts.   Your 150/1400 would be best suited upon an EQ3-class equatorial, if you wish to retain that type of mount for ease in tracking.  For tips on how to improve its performance...

https://stargazerslounge.com/topic/340294-celestron-powerseeker-127eq/

After I had done all that, it's a gem, and a keeper of keepers.

I did not collimate it with a laser; rather with passive tools, a collimation-cap and a Cheshire with cross-hairs.  That's the key to an exacting collimation...

...and the key to not having to replace it in future.

[mattjanes100]

Thanks again everyone, some really helpful responses. From what I can tell the OTA is of decent enough quality and it seems that the package was kept low cost with the tripod, mount and eyepieces included.

Will keep observing and in the mean time be saving for something of higher quality.

[Alan64]

I neglected to mention...

I call my Celestron 127/1000, albeit at f/8, my Celestron "C5", a C5 being a 127mm f/10 Schmidt-Cassegrain.  The former is an economical alternative to the latter.  Therefore, in the case of your 150/1400, its higher-priced equivalent is this one...

OTA... https://www.firstlightoptics.com/optical-tube-assemblies/celestron-c6-xlt-optical-tube-assembly.html

Kit... https://www.firstlightoptics.com/se-series/celestron-nexstar-6se.html

As for being of better quality, I can't really say.

[joe aguiar]

ohh sorry I thought was a 5" reflector didn't know it was a 6" as I was on my phone on my first reply so it was hard  to open link,

so yes your 6" scope will need a eq3 the eq2 is too light.

so if you ever upgrade then it should be to the 8"f/5 reflector on eq5 but its abit more heavier and bulky. But since u already have it use for now learn the sky, learn the consteallations and where objects are. That will get you started when you are ready for something bigger and better.

joejaguar

Edited October 22, 2019 by joe aguiar

[johninderby]

Bresser does a version on an EQ3.

https://www.bresser.de/en/Astronomy/Telescopes/BRESSER-Pollux-150-1400-EQ3-Telescope.html

[vlaiv]

3 minutes ago, johninderby said:

Bresser does a version on an EQ3.

https://www.bresser.de/en/Astronomy/Telescopes/BRESSER-Pollux-150-1400-EQ3-Telescope.html

That Pollux does not look like Bird-Jones. It looks more like F/5 newtonian with barlow lens. Bird Jones design should be more compact.

It might be that image on Bresser website is not true item, but compare that image:

To this telescope sold on TS website:

Ratio of diameter to physical OTA length don't match between the two, and one on Bresser website looks like regular F/5.

[johninderby]

Their description mentions the following though.

”Thanks to the catadioptic system (integrated barlow lens) the length of the tube is despite to its tall focal length kept short,”

The EQ2 version isn’t mentioned on the Bresser site so perhaps discontinued although Telescope House trades as Bresser UK and stuff is shipped from Germany? 

Edited October 22, 2019 by johninderby

[joe aguiar]

lots good info here for the poster to think about 

[vlaiv]

32 minutes ago, johninderby said:

Their description mentions the following though.

”Thanks to the catadioptic system (integrated barlow lens) the length of the tube is despite to its tall focal length kept short,”

The EQ2 version isn’t mentioned on the Bresser site so perhaps discontinued although Telescope House trades as Bresser UK and stuff is shipped from Germany? 

We could argue that their description is another "clue" to design of that specific telescope.

Bird Jones does not use simple barlow lens. It has spherical primary (rather fast - F/4 perhaps) and corrector lens. It is a bit similar to Mak-Newtonian - except Mak-Newt uses full aperture corrector plate and modifies wave front prior to primary mirror. Bird Jones modifies wave front "in converging beam" (after primary) - so it has different curve on corrector lens, and also as a consequence corrector lens needs to extend focal length to correct it. In any case it is not simple barlow lens, and it should not be called so.

There is no reason why regular barlow lens can't be mounted on parabolic newtonain before focuser at proper distance. Technically it would also be considered Catadioptic design - combining reflective and refractive elements.

[johninderby]

Get one and take it apart is perhaps the only definative answer.Seems well reviewed though.

[FLO]

I have never liked the Jones-Bird design so FLO has never stocked one. 

I do however feel a little sorry for Mr Jones and Mr Bird because their design doesn't have to be bad. It is just unfortunate that manufacturers appear to have utilised it only to reduce cost and generate high magnifications (usually higher than the telescope can support!). 

Another drawback is generally you cannot improve the view via higher quality eyepieces, the way you can with most regular Newtonians. 

Steve 

[mattjanes100]

Photos of mine attached. Does look like Bresser do a 150/700 version which would be the same scope without integrated Barlow. Seems I have misunderstood this to be bird-jones and it is in fact catadioptic?

 

Edited October 22, 2019 by mattjanes100
Just re-read previous response explaining difference

[vlaiv]

29 minutes ago, mattjanes100 said:

Photos of mine attached. Does look like Bresser do a 150/700 version which would be the same scope without integrated Barlow. Seems I have misunderstood this to be bird-jones and it is in fact catadioptic?

It could still be Bird Jones type telescope - spherical primary and corrector lens, only F/5 primary instead of faster F/4 like TS example above. Maybe in this slower configuration it is better optically?

Or it could be regular newtonian with a barlow. But what would be point in that? I mean you can buy regular 6" F/5 and use barlow on planets and use it without barlow to get wider field.

[mattjanes100]

I suspect you are correct, presumably if this had a parabolic mirror it would be stated.

[Ruud]

Bird-Jones (at the bottom of this page)

Note that the Bird-Jones spot diagrams for 30mm off axis are swollen up to such an extent that they do not fit in the diagrams.

Other correctors, in particular Houghton derived designs, work much better (Buchsroeder-Houghton for photographic use and Houghton for visual use).
 

from: Rutten and van Venrooij, Telescope Optics, a Comprehensive Manual for Amateur Astronomers

[Gottzi]

On 22/10/2019 at 19:28, mattjanes100 said:

Photos of mine attached. Does look like Bresser do a 150/700 version which would be the same scope without integrated Barlow. Seems I have misunderstood this to be bird-jones and it is in fact catadioptic?

Is Catadioptric not the same as Bird Jones?

Edited October 23, 2019 by Gottzi
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