Re: Which Camera?

Kenneth Tan

I have quite a few zwos . The 6200  is great . I would not get the 2400. The 2600 are ok.
Zwo Filter wheel design acceptable and convenient if you intend to use their system with the asi air pro. But not what i would say the best. A little rough around the edges in implementation. 
OAG best to avoid the zwo


On Fri, 2 Jul 2021 at 04:09, Roland Christen via <> wrote:
I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.


-----Original Message-----
From: Dale Ghent <daleg@...>
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my QUADTCC is as good of a solution.

> On Jul 1, 2021, at 01:54, ROBERT WYNNE <robert-wynne@...> wrote:
> Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.

With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference.  On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.

Roland Christen

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