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ZWO ASI 2600MM-PRO or QHY268M


ZWO ASI 2600MM-PRO or QHY268M   

31 members have voted

  1. 1. Poll: For those people definitely buying OR thinking about getting one of the above new cameras due to be delivered early 2021

    • ZWO ASI 2600MM - ORDERED ALREADY
    • ZWO ASI 2600MM - Will Definitely Buy
    • ZWO ASI 2600MM - I would like this camera
    • QHY268M - ORDERED ALREADY
    • QHY268M - Will Definitely Buy
    • QHY268M - I would like this camera

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  • Poll closed on 31/03/21 at 14:29

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FYI

Just received the following info from Rupert at Astrograph about the QHY268M cameras:

I have just opened up one of the 268M's we just had in to confirm what is supplied.

The camera provides 12.5mm BF from the back of the filter wheel.
It also  includes;

- a threaded M54 adapter of 4mm length giving you 16.5mm BF
- a threaded M48 adapter of 5mm length giving you 17.5mm BF
- 1 pc 1mm M54 spacer
- 3 pc 3mm M54 spacer
- 1 pc 10mm M54 spacer
- 1 pc M54 to 2" nose

So if you are using the SW flattener, this should have an 8mm spacer to M48 on the back of it which is 8mm thick. That is supposed to leave 55mm back focus.
The adapters supplied with the 268M, assuming the camera is bolted to the QHY CWF3-M-US will provide 44.5mm (1xM48 5mm, 1x1mm, 3x3mm, 1x10mm). This allows you to add a QHY OAG if need as that is 10mm and takes you up to 55mm. (Note the BF tolerance on the camera is +/- 0.5mm)
I also keep various adapter sets for the cameras, one of which includes 0.5mm, 1mm, 2mm, 3mm and 7mm. This would give you the 10mm otherwise needed. 

 

Just thought this might be useful for some to now up front 🙂 

Steve

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11 minutes ago, teoria_del_big_bang said:

FYI

Just received the following info from Rupert at Astrograph about the QHY268M cameras:

I have just opened up one of the 268M's we just had in to confirm what is supplied.

The camera provides 12.5mm BF from the back of the filter wheel.
It also  includes;

- a threaded M54 adapter of 4mm length giving you 16.5mm BF
- a threaded M48 adapter of 5mm length giving you 17.5mm BF
- 1 pc 1mm M54 spacer
- 3 pc 3mm M54 spacer
- 1 pc 10mm M54 spacer
- 1 pc M54 to 2" nose

So if you are using the SW flattener, this should have an 8mm spacer to M48 on the back of it which is 8mm thick. That is supposed to leave 55mm back focus.
The adapters supplied with the 268M, assuming the camera is bolted to the QHY CWF3-M-US will provide 44.5mm (1xM48 5mm, 1x1mm, 3x3mm, 1x10mm). This allows you to add a QHY OAG if need as that is 10mm and takes you up to 55mm. (Note the BF tolerance on the camera is +/- 0.5mm)
I also keep various adapter sets for the cameras, one of which includes 0.5mm, 1mm, 2mm, 3mm and 7mm. This would give you the 10mm otherwise needed. 

 

Just thought this might be useful for some to now up front 🙂 

Steve

Great info, thank you.

Looks like the package includes everything as stated by QHY in this post and diagram (blue and red), minus the filter wheel:

Image may contain: text that says "QHYCCD M48 Output 55mm 5mm 1mm 3mm 3mm 3mm OAGM 10mm COMBO A: CFW3M(US) 17.5mm 12.5mm QHY 268M For MPCC (M48, BFL=55mm) 0009 [28mm M3 Screws*6 it Or fix adapters] (To Replace) Removed From CFW 10mm OAG not used)"

Edited by Spongey
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Someone over on CN has got their QHY 268M. It seems it weighs less than expected, 812 grams, and is 107mm long. 

So good news that it's almost 200 grams lighter than expected 😃

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4 minutes ago, Xiga said:

Someone over on CN has got their QHY 268M. It seems it weighs less than expected, 812 grams, and is 107mm long. 

So good news that it's almost 200 grams lighter than expected 😃

That's good, so 112g heavier than ZWO and 10mm longer, I can definitely live with that, but full marks to ZWO still getting it down to 700g.

Steve

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  • 1 month later...

So, are there any out there who has gotten their hands on these cameras yet? Still haven't decided which one to choose.
+ for the QHY is the extended full well modes
+ for the slightly cheaper price
- is lack of USB hub and the weight

+ for the ZWO is the HUB and the weight
- for the price
- for the lack of extended full well modes - BUT, is this possible to change via a firmware/driver update? 

I love my SX filterwheel so I am keeping that, and the adapters are attached and screwed from the outside, which QHY FW is not... so, each time I need to adjust the camera, i need to open the FW cover...
The ZWO FW looks not dust and lightproof enough in their adaptation of the camera / corrector

/Daniel

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Posted (edited)
1 hour ago, Corpze said:

So, are there any out there who has gotten their hands on these cameras yet? Still haven't decided which one to choose.
I love my SX filterwheel so I am keeping that, and the adapters are attached and screwed from the outside, which QHY FW is not... so, each time I need to adjust the camera, i need to open the FW cover...
The ZWO FW looks not dust and lightproof enough in their adaptation of the camera / corrector

/Daniel

Daniel,

The problem is that very few people will have both cameras so people can only comment on the camera they have, with any certainty.

I had a SX FW with my ZWO ASI1600MM and like yourself very happy with it, it did everything I wanted and never failed me.
But when asking similar questions I was advised that due to the size of these cameras they ideally should be bolted to FW rather than screwed.
Certainly the QHY is considerably bigger and heavier than the 1600 and despite being a bit lighter the ZWO version is still much heavier. 
So taking this advise I went for the QHY camera and bought the QHY filter wheel to go with it then I know they would all bolt together correctly without bodging spacers of drilling holes.
The price of the QHY camera and FW was still about the same as the ZWO camera on its own.

Now I have the camera and FW I am not convinced you would suffer too much from screwing the camera to the FW but it could be the case especially if the front and back panels of the FW flex, which with my SW FW I think would be the case.

Also I am not sure how you would get the camera close coupled to the FW without bolting it on as I imagine you would have to use one of the spacers to do this and so the distance between the camera and FW would be greater than by bolting them together.
So if you have 2" filters then this may not be an issue but I think with unmounted 36 mm filters it may give you some issues with vignetting.

 

Regarding the USB hub that was something I was also not happy to lose, but the QHY filter wheel does connect directly to the QHY camera so I actually only lost one USB 2 port that I had used for the guide camera.
All in all I a really happy with the QHY camera and Filter wheel. The FW is very sturdy with a strong outer aluminium case that does not flex. Onl the downside it is a real PITA to get inside to change or clean filters when fitted to the rig but to keep the whole thing rigid then maybe no easy way around that.
I never had a ZWO FW to comment how they connect to cameras and what issues they have.

Steve

Edited by teoria_del_big_bang
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I am running a QHY 268M on a SX wheel using an M54 threaded adaptor. Not had much chance to play with it though as clear skies have been few and far between, and I've been spending most of my time sorting out borks between Sequence and the Sesto Senso on the ODK.

In my case the camera is on the TS apo rig, I run the FW into the ASA hub on the mount, and run a separate USB3 cable to the computer. Although there appears to be some vignetting it not major, and in any case flats take care of the problem.

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1 minute ago, robertm said:

Am also interested in the 268m and was wondering how good the cooling is - can it do a -40C delta from ambient ?

Thanks

Robert

The specs quote a -30 degree delta for continuous operation, or -35 degrees for single frames.

I can reliably cool mine to -10 degrees in a 21.5 degree room with the cooler at ~80% power.

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8 minutes ago, Spongey said:

The specs quote a -30 degree delta for continuous operation, or -35 degrees for single frames.

I can reliably cool mine to -10 degrees in a 21.5 degree room with the cooler at ~80% power.

I would 2nd that.

So certainly in UK it is sufficient as I do not see any need to cool below -10 C as there is no real benefit.
Maybe in hot countries where it is 25 C in night it might not reach the -10 C but otherwise should be ample cooling.

Steve

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It's also worth noting that this sensor has incredibly low dark current, even at higher temperatures.

Shooting a 300s exposure at 0 degrees will only give you 1.1e- per pixel of dark current, which is still well below read noise.

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Thanks all.  I have the ASI2600MC so know how good the sensor is.

I find the sensor in the ASI needs the tilt plate for correct alignment.  QHY quote that their sensor is well adjusted - can anyone quantify that for fast optics i.e. the tilt plate is unnecessary ?

Edit: By fast I mean f/2 or f/3

Edited by robertm
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On 24/03/2021 at 12:01, DaveS said:

I am running a QHY 268M on a SX wheel using an M54 threaded adaptor. Not had much chance to play with it though as clear skies have been few and far between, and I've been spending most of my time sorting out borks between Sequence and the Sesto Senso on the ODK.

In my case the camera is on the TS apo rig, I run the FW into the ASA hub on the mount, and run a separate USB3 cable to the computer. Although there appears to be some vignetting it not major, and in any case flats take care of the problem.

Thank you so much for the input.

I am thinking that i will use the SX adapters to directly couple the camera (if it will be QHY or ZWO, I haven't decided yet) No spacers or anything, and according to calculators online, the distance between the filters and the chip is ok regards to vignetting.

The backplate on the SX FW might be rigid enough or it won't, i guess it has to be trail and error before i buy a new FW...

I made a video regarding my choise of brand... this isn't easy guys ;)

 

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  • 2 weeks later...

I wonder if that comparison on dark current etc is valid.

Since both cameras use the same sensor (presumably), there shouldn't be any difference in their specs, correct?

To me, the weight/size differences and the software drivers seem to be the real difference (and the USB hub). Also, note the RisingCam/Rising Tech/Touptek version of IMX571 (I think that's being sold by Altair Astro?)

N.F.

 

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  • 2 weeks later...
On 07/04/2021 at 21:21, nfotis said:

I wonder if that comparison on dark current etc is valid.

Since both cameras use the same sensor (presumably), there shouldn't be any difference in their specs, correct?

To me, the weight/size differences and the software drivers seem to be the real difference (and the USB hub). Also, note the RisingCam/Rising Tech/Touptek version of IMX571 (I think that's being sold by Altair Astro?)

N.F.

 

It should be the same, but it might be a difference on how they measure it and possibly the driver / read out mode which might have an impact - not sure though...

Yes they are several IMX571 cameras coming out.. Altair and also Moravian C3 and C3+ but they have some gaps in their data... about half of the specs is on their website... no data on buffer size and dark current etc.

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  • 4 weeks later...

So, the question weather the SX FW back plate holding the camera flexing or not has been running around in my head, so i decided to measure the flex...
Spoiler - It is probably good to go.

I also pushed the button for a new camera... I think it will be a good choise for me :)

https://youtu.be/jPklF0Gl2BA

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