Is Bresser EXOS2 good? - Forums

Topic starter

Jun 29, 2023 · Edited: Jun 29, 2023

Hello. Does anyone know or use this telescope? In my country this telescope is very cheap compared to others (https://www.amazon.com.tr/Bresser-Messier-teleskop-1000-Hexafoc-Exos-2-Goto/dp/B00NBUO4PS#aw-udpv3-customer-reviews_feature_div). Is there a guide port to connect it to the computer? Is it suitable for astrophotography? I'm sure this 8-inch newtonian and this mount isn't good for astrophotography, but how many seconds of exposure would I get if it did? and finally what are the advantages and disadvantages compared to Celestron AVX? I would be very happy if you explain in detail.

Thanks.

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ricardo leite

Jun 29, 2023

https://www.cloudynights.com/topic/775652-bresser-exos-2-goto-mount-connection-to-pc-doesn%E2%80%99t-work-properly/

I have series difficulties to connect on the computer, andthe guiding does not work. Maybe it would be necessary to buy an extra module:

https://pt.aliexpress.com/item/1005005545127070.html?pdp_npi=2%40dis%21BRL%21R%241.241%2C99%21R%24695%2C52%21%21%21%21%21%402101f01816880506855877880e3ca3%2112000033481301837%21btf&_t=pvid%3A31924ac2-6775-43c1-b278-a10ab54aa61d&afTraceInfo=1005005545127070__pc__pcBridgePPC__xxxxxx__1688050685&spm=a2g0o.ppclist.product.mainProduct&gatewayAdapt=glo2bra

Pinguru

Jun 29, 2023

I can tell you something about the EXOS-2 Hardware (the mount itself).
I started with the manual version and upgraded it with an OnStep-System purchased from ebay. This set converted the Exos-2 into a 625€ (375 Mount + 250 OnStep) Goto-Mount. If this was my budget today, I would take the same route.
The periodic error of the wormgears is in the range of 15-25 arcsec. I think this is a fair performance.
Out of the box the mount needed some cleaning and greasing to work properly. This is the price to pay for a relatively cheap mount. So don't be scared taking this whole thing apart.
I have just indroduced guiding and the performance is ok. It is solid under 1" RMS error in RA. But DEC is a mess. You will need superb polar alignment and disable DEC guiding or intentionally misalign and just allow for single direction DEC guiding. Otherwise the backlash and other factors will ruin almost every sub exposure with DEC oszillation.
Because of this, Dithering does not work properly. Not even just in RA.

Bresser says, that this mount is primarily designed vor visual astronomy and allows to begin with photography. This is true, as far as I can tell.
My experience is based on the 150PDS, so a lighter 6" newtonian. The performance should be worse with the 8" newtonian.

You can check out my pictures, they all have been made with this mount.

If you are short on budget and willing to fiddle around: go for it.
If you have some money to spend: Go for the HEQ5 and maybe add the Belt-Mod.

Regards, Volker

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Vahur Sinijärv

Jun 29, 2023

It is certainly possible to use this mount for astrophotography. Here's a picture I took in May, taken with similar telescope, 800mm focal length version, NT203s/800 and the same mount.

M101, Pinwheel Galaxy

You need to use guiding. I've not had good results with unguided. 3-5 sec probably, depends on polar alignment. With guiding, it's possible to have sub arcsecond tracking. There's ST4 port for guiding. You can also order or make yourself a cable which connects to the hand controller and allows computer to control it. Third way - which I'm using - is to make a custom cable which connects to motors directly, bypassing the hand controller and use my PMC8->EXOS2 bridge driver for ASIAIR to control it.
ST4 is the simplest if you have a guide camera with ST4 output. But bear in mind that astrophotography won't be easy with this mount and telescope (or is it ever), because of relatively long focal length. You'll probably want OAG to get better guiding and you absolutely *have* to have Explore Scientific coma corrector, otherwise stars will look more like seagulls the further way from center they are. Maybe it's a bit better with 1000mm f/5 version, but for 800mm f/4 it is a must have.

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Ömer S. Işık

Topic starter

Jun 29, 2023

Thank you very much for all your answers. Sorry, I have to ask my question in TL. The price of this telescope is 34.000 TL. In other words, I give 34.000 TL and buy both 8 inch ota and exos 2 mount. But if I pay 45,000 TL, I will have bought both an AVX and a 6 inch newtonian (C6-N). Which one would make more sense to buy at these prices? I want it for both observation and ap. I have experience of Ap for 8 inch newtonian. Does avx deserve such a price difference? I also think I can do prime focus with 2 ota and dslr.

Ömer S. Işık

Topic starter

Jun 29, 2023

Vahur Sinijärv:
It is certainly possible to use this mount for astrophotography. Here's a picture I took in May, taken with similar telescope, 800mm focal length version, NT203s/800 and the same mount.

M101, Pinwheel Galaxy

You need to use guiding. I've not had good results with unguided. 3-5 sec probably, depends on polar alignment. With guiding, it's possible to have sub arcsecond tracking. There's ST4 port for guiding. You can also order or make yourself a cable which connects to the hand controller and allows computer to control it. Third way - which I'm using - is to make a custom cable which connects to motors directly, bypassing the hand controller and use my PMC8->EXOS2 bridge driver for ASIAIR to control it.
ST4 is the simplest if you have a guide camera with ST4 output. But bear in mind that astrophotography won't be easy with this mount and telescope (or is it ever), because of relatively long focal length. You'll probably want OAG to get better guiding and you absolutely *have* to have Explore Scientific coma corrector, otherwise stars will look more like seagulls the further way from center they are. Maybe it's a bit better with 1000mm f/5 version, but for 800mm f/4 it is a must have.

The photo is really beautiful. May I know how many seconds of exposure you took for a light frame?

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Vahur Sinijärv

Jun 29, 2023

The photo is really beautiful. May I know how many seconds of exposure you took for a light frame?

Thanks. It's about 12h of exposure in total.

A. Wegdan

Jun 29, 2023

As a mount yes, but the stock go to system is horrible, might be ok for visual but not for astrophotography. That being said, several users on astrobin have produced amazing results with it, but almost all have had custom onstep controllers.

Ömer S. Işık

Topic starter

Jun 29, 2023

As a mount yes, but the stock go to system is horrible, might be ok for visual but not for astrophotography. That being said, several users on astrobin have produced amazing results with it, but almost all have had custom onstep controllers.

Thank you for the answer. i wonder how much better avx is than exos2

Gaiden

Jun 29, 2023

hi!
i'm actually use this mount (not the PMC-8: you pay attention, they are really different. PMC8 is better) for astrophotography.
you can control it by the bresser cable (it sucks but it works).
I use it with a 80ED refractor and after I spent months I'm still searching the right settings to work good with this mount.

balancing is the HELL: I had to replace the eth spring cable cause it still pull the mount. after this I had to add the counterweights to balance the AR motor's weight. but guiding is still a pity, AR errors are totally crazy and the average exposing time is 240" at max.

long short story: I ordered a SkyWatcher EQ6R-PRO.

EXOS2 is very good for visual or planetary imaging, but DSO photography it's not for it. no way.

Ömer S. Işık

Topic starter

Jun 29, 2023

hi!
i'm actually use this mount (not the PMC-8: you pay attention, they are really different. PMC8 is better) for astrophotography.
you can control it by the bresser cable (it sucks but it works).
I use it with a 80ED refractor and after I spent months I'm still searching the right settings to work good with this mount.

balancing is the HELL: I had to replace the eth spring cable cause it still pull the mount. after this I had to add the counterweights to balance the AR motor's weight. but guiding is still a pity, AR errors are totally crazy and the average exposing time is 240" at max.

long short story: I ordered a SkyWatcher EQ6R-PRO.

EXOS2 is very good for visual or planetary imaging, but DSO photography it's not for it. no way.

Thank you for this information. The information you provide is really valuable and important.

A. Wegdan

Jun 29, 2023

I totally agree with @Gaiden on that it’s not in anyway made for DSO especially the one you put in the link. I think you would be better off purchasing a scope and mount separately. On that note it all depends on the focal length you plan to use and your budget. I have an AM5 and a CGEM, I’m happy with both. The am5 is way more portable and much easier to use than the CGEM.

I gave up on my EXOS2, it was too cumbersome

Ömer S. Işık

Topic starter

Jun 30, 2023

Thank you all for your answers. AVX and I think c6-n would be a more sensible decision. It may be more logical and stable to get apo with AVX, but c6-n is cheaper and more logical since I want to do both ap and observation.

Tareq Abdulla

Jun 30, 2023

I totally agree with @Gaiden on that it’s not in anyway made for DSO especially the one you put in the link. I think you would be better off purchasing a scope and mount separately. On that note it all depends on the focal length you plan to use and your budget. I have an AM5 and a CGEM, I’m happy with both. The am5 is way more portable and much easier to use than the CGEM.

I gave up on my EXOS2, it was too cumbersome

I bought AZ-EQ6 in the past with cheaper price but still expensive and i can't afford it again nowadays if i have to, AM5 and CGEM each is more expensive than EQ6 mount no matter how great they are, i want to buy a second mount another one but so cheap for DSO, and i won't use big scopes on it, but something like 60mm/70mm scopes with few minimal accessories, so i am also with OP here.

Tareq Abdulla

Jun 30, 2023

hi!
i'm actually use this mount (not the PMC-8: you pay attention, they are really different. PMC8 is better) for astrophotography.
you can control it by the bresser cable (it sucks but it works).
I use it with a 80ED refractor and after I spent months I'm still searching the right settings to work good with this mount.

balancing is the HELL: I had to replace the eth spring cable cause it still pull the mount. after this I had to add the counterweights to balance the AR motor's weight. but guiding is still a pity, AR errors are totally crazy and the average exposing time is 240" at max.

long short story: I ordered a SkyWatcher EQ6R-PRO.

EXOS2 is very good for visual or planetary imaging, but DSO photography it's not for it. no way.

The one he linked i could buy it and use it for DSO with one change, i just change the scope to something smaller such a 60mm or 70mm refractor, i think that can be handled fine with the mount, not 8", i even won't think to use 6" Newt on it, so it can be used for DSO with a correct scope and accessories.