Bresser Messier 203 f5 Newt

[900SL]

Anybody have one of these for imaging? Any good or a cheap exercise in frustration?

Is there a matching coma corrector?  Appears to be the same as the Explore Scientific First light models

 

 

 

[900SL]

Bump..

 

Contacted Bresser and they suggest the ES HR coma corrector, basically remove the helical focuser/eyepiece connector, FLO link here

https://www.firstlightoptics.com/coma-correctors/explore-scientific-hr-coma-corrector.html

Backfocus for imaging around 55mm

I assume the coma corrector doesn't project into the tube for imaging?

Anybody use the F5 version Newt for imaging? 

 

 

 

 

 

 

 

 

 

Edited June 3, 2023 by 900SL

[ONIKKINEN]

Cant offer you the first hand experience you were looking for, but will say a few things that i can read between the lines of the product description anyway.

The telescope is very cheap, suspiciously cheap even. Realistically you cant expect the thing to be a ready astrophotography platform when the very low price includes: The scope, plate and rings, an eyepiece, a finder, some adapters. The accessories without the scope will cost almost the 500€ this seems to be sold if of good quality. You should be expecting a factory standard newtonian which will require the usual modifications to get going, which would be: Flocking of the tube since the images seem to show a mostly gray rather than black inner tube, longer plate since the stock one is very narrow and you should expect stability issues with it. Might even want to add a top plate to tie the rings together. The tube seems to be steel from the stated weight of 11.2 which is good, so it doesn't buckle like an aluminum VX8 for example. The mirror cell could require some work if the mirror is not stable enough, or if it is too stable and you get pinching in the Finnish winter conditions the scope will presumably spend some time in. The scope is cheaper than just a 200mm f/5 mirror that comes with a certificate stating its at least "ok", so you should probably not be shocked if there is some turned down edge or similar minor aberration on the primary (that one is hidden with a primary mirror mask). Focuser might be ok, might be not. They seem to cling on to the hexafoc name in the description so maybe this is a strong part of the scope, if not, expect to get rid of it for again almost the price of the whole scope.

Long story short, the scope is a third of the price i would expect it to be in order to trust it as a ready to go scope and you should probably expect to tear it down and modify it.

The TS GPU 1.0x corrector is also a good option, spot diagram below:

For comparison the ER one you linked below:

RMS radius numbers are similar for both (ignore everything else, the images are at different scales), but a little bit flatter for the GPU which might translate to easier focusing and fewer noticeable differences in focus at the edges. The flatness part is good for a newtonian since slightly out of focus stars will have out of focus diffraction spikes, making the aberration immediately obvious. The HR diagram also only shows up to 15mm radius, while the TS GPU goes all the way to 22mm. From these 2 i would choose the GPU.

And on the focuser intruding issue, it might, depending on how they have configured the scope and its focal point. It comes with an eyepiece and is shown in images with a DSLR so it has to be designed in a way that allows an eyepiece and a much deeper backfocus requiring imaging train to be at focus. Because of that i think the focuser will be poking out the inside of the tube a little bit since for imaging purposes the focuser would be racked in more than with an eyepiece. This will create either an extra diffraction spike, or some general diffraction messiness around bright stars. To get rid of you would be chopping the focuser tube shorter or pushing the primary mirror up the tube.

Hope i scared you just the right amount and not too much so as to not want a newtonian. When/if it works well you get a blazing fast scope that i think truly can do it all or at least a little bit of it all.

[900SL]

Kiitos Oskari,  that reality check  has me walking on the other side of the river 😀 

I assumed the accessories would be junk. The focuser, tube and mirror appear to be similar to the Explore Scientific line dobsonians which seem to be well regarded, however, and being realistic, it is likely to require a bit of work to get a good imaging set up at that price. 

it's also fairly heavy and being a steel tube, likely to require more refocusing

I'm now looking at the 6" TS ONTC or UNC newts..

[R26 oldtimer]

I am using the 150nt for imaging. As it comes from the factory, it is a better scope than the equivalent pds. Bigger bore R&P focuser vs the 2" crayford of the SW and oversized secondary compared to the pds. Used it until last year with a GSO cc which was pretty ok but now moved to a GPU cc. Focuser does not protrude into the light path with either CC's and doesn't have any noticable sag loaded with oag, SX heavy filter wheel and mono camera.

While the focuser doesn't seem to sag with weight, the telescope thin metal metal tube deforms slightly under a heavy imaging train, so for better results another tube or some reinforcement around the focuser section of the tube is needed. My guess is that this will be more noticable in the 8" version scope.

Edited June 5, 2023 by R26 oldtimer