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Bresser 102L/1350 came with extension tubes! Is the lens collimateable?

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#1 XyrcesFenol

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Posted 08 August 2017 - 10:20 AM

I have just bought a Bresser 102L/1350 from the nice people at Telescope Service, to share the ES Twillight II mount with the C90 Mak.

 

(This is what happens when you read threads with the title "New Bresser long focus achromatic refractors".)

 

The low price has good WAF (wife acceptance factor) while saving up to a ES 127. And somehow I do feel more like a proper dressed gentleman with the large white tube mounted. I can not describe it better.

 

To my happy surprise it came with more things than described, 2 focuser extension tubes of 25 and 37mm. smile.gif

 

Bresser 102-1350 14b.jpg

 

The dew shield is not retractable, but top part can be removed if pulled forward gently, please see attached pic.

 

To me the smaller hex screws with some glue on looks like collimation adjustments. (There are two more on the back side.) Can anyone with more knowledge share some thoughts on that?

 

Bresser 102-1350 10.jpg   

Bresser 102-1350 3.jpg

 

(And yes, first light in the telescope showed a much more pleasing and contrast rich view compared to my Celestron C90 mak, focusing depth is greater and it also puts less strain in my eye, maybe due to less field curvature? I move the TS dielectric diagonal and using same the EP when comparing. I am very satisfied.)

 


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#2 Allanbarth1

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Posted 08 August 2017 - 11:03 AM

I would say those are not collimation adjustments. In my experience refractors with lens cells that can be collimated have the adjustments next to the lens. 

If you were to look dead on at the lens you would see the adjustment screws. They look like this....

 

http://www.ozscopes....-telescope.html

 

Here is a nice article on the how to part of refractor collimation if your curious.

 

http://philjay2000.t.../adventures.pdf


Edited by Allanbarth1, 08 August 2017 - 11:30 AM.

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#3 Gabby76

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Posted 08 August 2017 - 11:47 AM

I would say the screws on the tube side hold the lens cell in place and the smaller screws towards the lens center the cell.
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#4 Gofr

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Posted 08 August 2017 - 11:59 AM

My hero!!! I've been wanting to get this scope for ages and still do. Would love a more in depth report of the scope when you can, specifically how well it mounts and what your recommendations for mounting it are. (I caved in for the Bresser 5 inch mak for now instead as I felt my EQ2 would handle it better than an F13 4 inch refractor.)


Edited by Gofr, 08 August 2017 - 12:03 PM.

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#5 T1R2

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Posted 08 August 2017 - 08:41 PM

non-collimatable, and at f13, long focus refractors like this if done properly at the factory wont ever need it.

 

so if the high power views are razor sharp , its collimated correctly, and will remain so even if the cell is removed off the front of the scope, lenses taken out and cleaned and reassembled, everything should assemble back together and work just as if it was new.


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#6 XyrcesFenol

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Posted 10 August 2017 - 07:25 AM

My hero!!! I've been wanting to get this scope for ages and still do. Would love a more in depth report of the scope when you can, specifically how well it mounts and what your recommendations for mounting it are. (I caved in for the Bresser 5 inch mak for now instead as I felt my EQ2 would handle it better than an F13 4 inch refractor.)

 

For a goto mount my best quess is a NEQ6/Altlas class. The telescope is lighter to handle than it looks like, but more sensitive to wind compared to a mak.

 

With the Twilligt II mount it settles in less than a second after a re-focus, without any vibration suppression pads.

 

Changing between light and heavy EP's also needs more compensation.

 

My current setup is this manual alt/az push to mount:

post-201581-0-66824000-1454700474_thumb.jpg

 

Guess I have to get a bigger hammer...


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#7 Gofr

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Posted 12 August 2017 - 07:51 AM

Couple quick questions. What's the OD size of the lens without the dew cap and the size of the OD of the dew cap? Also, how long did it take TS to ship the scope over?



#8 XyrcesFenol

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Posted 14 August 2017 - 02:57 PM

Couple quick questions. What's the OD size of the lens without the dew cap and the size of the OD of the dew cap? Also, how long did it take TS to ship the scope over?

 

OD of white dew shield is 125mm. It has a black plastic termination on the front end that is a little bigger, like the dew cap OD 131mm.

 

OD of black lens cell, front part/ring 117mm

 

The black lens cell is somewhat larger to the back to hold the dew cap, see picture

 in first post. Appr 121mm. The dew shield slides on them and gets pressed in under the red ring.

 

(Size in mm, as I understand even the US is slowly going metric, inch by inch)

 

Shipping time to Canada or US needs to be checked with Teleskop Service, as I live in the northern Europe.

 

Note: When bought, the warranty period can be extended by product registration on bresser web:

http://archive.bress...gistration.html



#9 AaronM

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Posted 09 January 2018 - 01:37 PM

Dear friends,

 

sorry to reactivate this old thread, but do I see it correct - the lens cell is made of plastic ?????

 

Kind regards, Michael Aaron



#10 Gofr

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Posted 09 January 2018 - 01:41 PM

Old temptations resurfacing.....

#11 AaronM

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Posted 10 January 2018 - 07:35 AM

Hello again,

 

please correct me, if I'm totally wrong, BUT :

 

1. the lenscell is made of plastic ?

 

2. one can screw out/in the hole lens-holder , but

 

3. no push&pull screws for adjusting the obejctive ?

 

4. These little 2 screws at the side of the cell are only for fixing the "lens-holder" ?

 

If these points are correct, this is a totally missmatch for mecrazy.gif

 

A curious construction : we have here a higher end focuser ( Hexafoc ), but on the other end such a strange cell-construction ?

 

Kind regards, Michael Aaron


Edited by AaronM, 10 January 2018 - 08:28 AM.


#12 BillP

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Posted 10 January 2018 - 10:17 PM

 If these points are correct, this is a totally missmatch for mecrazy.gif

 

At a price point of € 259.00 incl. VAT for the OTA one cannot expect a similar build that is on more expensive scopes.  At these long focal ratios collimation is not all that critical.  I had an f/16 scope and I could move the collimation way off and it still presented a razor sharp view.  Was cool how forgiving it was.  I also had some old 60+ year old refractors with plastic parts holding the objective.  Was no issue...they did their job for 60 years and continue to.  I imagine if they went to all metal construction throughout and complex collimatable setup the price would probably triple.  The main objective does not encounter much physical use on a refractor...better money spent on the focuser which gets heavy use.

 

I think it is great that there are some good optics in lesser builds so things like this can be offered at such good price points.  I wish the Bresser 90L and 102L were available in the U.S. as would love to take a look at one and potentially get one. 


Edited by BillP, 11 January 2018 - 12:40 PM.

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#13 XyrcesFenol

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Posted 15 January 2018 - 01:46 PM

The views are way better than in the now ever in the box sleeping c90. The stars are more pin point, easier to split and views simply sharper. And easier to get into focus. Maybe the c90 is a lemon, but I am now just using the Bresser long achromat.

 

(It will need a counterweight on the Twilight II to get the old smoothness back though, it is alittle sticky without but I lived with it so far.)

 

So I am very happy with this scope and not worried about the collimation as when starting this thread.



#14 rogeriomagellan

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Posted 16 January 2018 - 03:38 PM

From the picture posted, I've got the impression that it can't be collimated. 

 

But since you are getting good views with it, I believe that the lens cells are doing their job well. It means that the construction is good enough. And you were really wise to purchase a TS 2" dielectric diagonal mirror with the scope.



#15 rogeriomagellan

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Posted 16 January 2018 - 03:41 PM

 

 If these points are correct, this is a totally missmatch for mecrazy.gif

 

At a price point of € 259.00 incl. VAT for the OTA one cannot expect a similar build that is on more expensive scopes.  At these long focal ratios collimation is not all that critical.  I had an f/16 scope and I could move the collimation way off and it still presented a razor sharp view.  Was cool how forgiving it was.  I also had some old 60+ year old refractors with plastic parts holding the objective.  Was no issue...they did their job for 60 years and continue to.  I imagine if they went to all metal construction throughout and complex collimatable setup the price would probably triple.  The main objective does not encounter much physical use on a refractor...better money spent on the focuser which gets heavy use.

 

I think it is great that there are some good optics in lesser builds so things like this can be offered at such good price points.  I wish the Bresser 90L and 102L were available in the U.S. as would love to take a look at one and potentially get one. 

 

I guess that the only way to get it now is ordering from TS website, Bill. Shipping costs are not prohibitive, though. 



#16 AaronM

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Posted 18 January 2018 - 01:32 PM

Hello,

shippimng cost from germany to USA displayed here as : 36€ with Post and 57€ via UPS Express

 

regards, Michael Aaron

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  • shipping.jpg



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