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CCD v CMOS


centroid
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2 hours ago, Stuart1971 said:

You are in the exact same position as me, and feeling the same as me, I have used CCD for years and decided to move to the QHY268c  and I too am a little disappointed, my images are full of noise and not pretty at all, and yet I read how much more sensitive these CMOS cameras are but I don’t see it at all, the quirks and trying to get correct gains and offsets, it driving my nuts, and I too am thinking of a return to CCD, this CMOS lark is just not what it was advertised as, unless I am doing something seriously wrong, which I doubt, I would love to know where and how all the superb images on here were created, it does make me wonder how much of them were created in the processing and not the camera, which is not really for me….☹️

It is a whole new "ball game" for us 'old timers' Stuart,  some of us who cut our astro imaging teeth on things like the Philips Toyu web cam (at least I think that is what it was called), before moving onto CCD astro cameras, usuallly Steve Chambers Atik products, or as in my case the Terry Platt/Michael Hattey Starlight Xpress cameras.

I had an MX5c, H9c, H9, and finally the H16..

With Sony ceasing to make CCDs , the astro camera manufacturing market had to look for alternative technology, and the obvious choice was I guess, the CMOS device, already used in digital cameras. As you might expect, the Chinese were quick to seize on the opportunity.

I don't know how long the likes of Atik and Starlight Xpress will continue producing CCD astro cams, until they run out of CCDs I guess. Whether or not they will eventually switch over to CMOS, or cease manufacturing astro cams altogether, is anyone's guess.

I think we have three choices, accept the CMOS astro cams with their quirks, and learn to work with them, go back to CCD, while we still can, or give up astro imaging.

For me, I will continue to experiment with the 294c, despite its quirks.

I have seen some very nice images produced with both the 294, and other models, but as I said earlier, I think that is down to the processing skills of the user. As a keen photographer, I enjoy processing digital images, and processing astro images, is an extension of that, albeit in many ways different, but all surmountable.

Imaging with the CMOS astro cam, I have found very different to CCD, and nowhere near as user friendly. Gain and black level setting, severe amp glow/starburst, and poor colour balance (green tint). Taking an image, checking the Histogram, makes setting the black point relatively straight forward, although I discovered that you need to do this for each exposure length, which is a bit of pain. I discovered this when I set the black point for a batch of 15s subs on the core of M42, and then using the same black point setting for the 90s subs, the subsequent Histogram showed the black point was way off optimum. Never had to concern ourselves with a black point setting with CCD.

However, it is what it is, and we can't turn back time.

Edited by centroid
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Hello Dave - I started astro-imaging back in 2000, where I used a Philips Vesta webcam to do lunar and planetary imaging, and I was then one of the few people in the world who had a SAC-7 long exposure camera (that I imported from the UK). I also had a few Atik CCD cameras. What put me off back in those days was the tiny sensor size - it was often a struggle to get the object onto the sensor (especially as I didn't have a Goto scope). I now use a ZWO 071 which has an APS-C sized sensor, and if I use that on a WO 81 refractor, the field of view is almost 3 degrees by 2 degrees!

Speaking for myself, I use either 30 secs or 60 secs exposure with a UV/IR filter, and always keep the same gain value and cool the sensor to the same temperature (I tend to use a high gain of 200, and cool the sensor to -5C). If I use the L-enhance filter I tend to use 2 min exposures. If you keep the same settings, you can use the same dark and bias library. Taking flats is usually quite quick and easy to do using an LED light panel.

You can definitely get good results with some of the modern CMOS cameras, but if you are used to CCDs, it will be a change, particularly with regard to taking shorter subs and stacking more of them. I would also encourage you to play with the gain. Although many imagers seem to prefer unity (or lower) gain, there are a few of us who prefer higher gain and even shorter subs (the benefit of higher gain is also lower noise). The image below is just from 2 hours of 2 min exposures (using gain setting of 200 and the L-enhance filter) on the Rosette nebula, using the ZWO 071 camera (on the WO 81 f5.9 refractor) 

Rosette Nebula 11th Jan v2 2022.jpg

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1 hour ago, Phillyo said:

Stick with it. I moved from CCD to CMOS and much prefer CMOS. I use an ASI533 and it's great. The reason you're seeing more noise is probably short sub lengths compared to CCD. However, if you increase your total integration time to the same as you did with CCD you should see the noise drop and a LOT more signal come through. Imaging with a colour sensor with a bright moon is going to produce lots of noise unfortunately. Try it without the moon and give it lots of integration time, you'll get the results you want. 

I will be sticking with it for now Phil, especially after investing quite a few £k in new astro gear, I sold everything back in 2014, and with no intention of returning to astro, but here I am again 🙂

'Noise' I can cope/deal with, but the strange quirks of astro imaging with a CMOS camera, will take some getting used to, but I will hopefully.

It has become apparent since starting this 'thread', that the 294 CMOS sensor is now quite old tech, and that certainly shows in its severe amp glow/starburst. But I gather the 2600 is a newer design, and much improved.

I run a successful photography forum, and I maintain that there is much more to a good photography forum, than just posting pictures, and the same goes for astro forums. Discussion is an important part, for sharing  knowledge, providing guidance, and creating a community with a common interest. The discussion in this 'thread' has done just that. 👍

There are still a number of members here that I remember from 'back in the day', many of whom I had the pleasure of meeting in person, at Kelling Heath, and an SGL meet.

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1 hour ago, Stuart1971 said:

You are in the exact same position as me, and feeling the same as me, I have used CCD for years and decided to move to the QHY268c  and I too am a little disappointed, my images are full of noise and not pretty at all, and yet I read how much more sensitive these CMOS cameras are but I don’t see it at all, the quirks and trying to get correct gains and offsets, it driving my nuts, and I too am thinking of a return to CCD, this CMOS lark is just not what it was advertised as, unless I am doing something seriously wrong, which I doubt, I would love to know where and how all the superb images on here were created, it does make me wonder how much of them were created in the processing more so than the camera..But I will stick at it after shelling out over £1600 on this new QHY268c camera, I guess this past week has not been the best time for imaging with the moon around every night…so maybe I was expecting a bit too much…time will tell…👍🏼

I was very impressed d with the early IMX571 OSC images that were coming up on here, particularly @gorann's posts with the RASA8/ASI2600c. I thought  "I must have some of that" and purchased the same scope and camera. To date I haven't managed to replicate his results,  but he does have a nice dark sky, superior processing skills, I'm sure and now also a dual RASA rig! However on my dual refractor rig  I have found capturing RGB with the OSC so much easier than my mono CCD and filters, especially with the constraints imposed  by the UK climate.

So much so I have bought another budget IMX571 camera to see if dual CMOS can deliver results comparable to CCD Lum and CMOS RGB. 

I would like to think I have an open mind on the subject of CCD vs CMOS, and ultimately will settle on the combination that gives for me the best balance of capture convenience and final image quality. Until recently image processing complexity would have been a big part of the equation but I have a lot of time on my hands being retired so I am gradually warming to the software processing side of this hobby.

 

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Atik already produce camera's with cmos sensors.. as do starlight xpress...

Atik are working on new technology  all the time as I'm sure starlight xpress do...

Note how they pic out what sensors the want to use and just run those, rather than having a massive portfolio of products that get superseded all the time.. great to see they use the imx571 sensor..

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9 minutes ago, iantaylor2uk said:

Hello Dave - I started astro-imaging back in 2000, where I used a Philips Vesta webcam to do lunar and planetary imaging, and I was then one of the few people in the world who had a SAC-7 long exposure camera (that I imported from the UK). I also had a few Atik CCD cameras. What put me off back in those days was the tiny sensor size - it was often a struggle to get the object onto the sensor (especially as I didn't have a Goto scope). I now use a ZWO 071 which has an APS-C sized sensor, and if I use that on a WO 81 refractor, the field of view is almost 3 degrees by 2 degrees!

Speaking for myself, I use either 30 secs or 60 secs exposure with a UV/IR filter, and always keep the same gain value and cool the sensor to the same temperature (I tend to use a high gain of 200, and cool the sensor to -5C). If I use the L-enhance filter I tend to use 2 min exposures. If you keep the same settings, you can use the same dark and bias library. Taking flats is usually quite quick and easy to do using an LED light panel.

You can definitely get good results with some of the modern CMOS cameras, but if you are used to CCDs, it will be a change, particularly with regard to taking shorter subs and stacking more of them. I would also encourage you to play with the gain. Although many imagers seem to prefer unity (or lower) gain, there are a few of us who prefer higher gain and even shorter subs (the benefit of higher gain is also lower noise). The image below is just from 2 hours of 2 min exposures (using gain setting of 200 and the L-enhance filter) on the Rosette nebula, using the ZWO 071 camera (on the WO 81 f5.9 refractor) 

Rosette Nebula 11th Jan v2 2022.jpg

Hi Ian, very interesting, thank you.

Its early days yet, and I am still recovering from the shock 😅, of discovering just how quirky CMOS astro is,  and not so user friendly as CCD's were. However, I will persist, and, maybe as Martin said, I will get to like them.

It is said that "you can't teach an old dog new tricks", but this "old dog" will learn 🙂.

It always good see input from those people such as yourself, that have experienced both CCD and CMOS, because that has substance. There will be a lot of people there that have never astro imaged with CCD camera, so cannot compare them.

 

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Just as a lurker in many threads about calibration i have noticed that the 294 is often the camera in question when someone has a calibration issue. Maybe this particular sensor is more temperamental than others from the bag of available CMOS sensors?

Could it have something to do with the native pixel size being 2.32 microns and the OSC version is binned 2x2 by default? At least thats what i think is going on, the mono version of the sensor has an unlockable BIN1 mode where the actual pixel size of 2.32 is used instead of the OSC 4.64.

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3 minutes ago, newbie alert said:

Atik already produce camera's with cmos sensors.. as do starlight xpress...

Atik are working on new technology  all the time as I'm sure starlight xpress do...

Note how they pic out what sensors the want to use and just run those, rather than having a massive portfolio of products that get superseded all the time.. great to see they use the imx571 sensor..

That is something that I was not aware of, and good to hear. 🙂

I would love to support Atik or SX British designed and built CMOS astro cams, even though they will likely be more expensive than those emanating from China.

As you imply, there is a greater variety of Chinese (Touptek and ZWO) cameras,  than you can "shake a stick at". 

I guess more about grabbing a bigger slice of the market, than producing a smaller range of "ideal for purpose" cameras.

I wish Steve Chambers (Atik) ,and Terry Platt/Michael Hattey the best of luck with their new venture. I will watch their progress with great interest.

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31 minutes ago, ONIKKINEN said:

Just as a lurker in many threads about calibration i have noticed that the 294 is often the camera in question when someone has a calibration issue. Maybe this particular sensor is more temperamental than others from the bag of available CMOS sensors?

Could it have something to do with the native pixel size being 2.32 microns and the OSC version is binned 2x2 by default? At least thats what i think is going on, the mono version of the sensor has an unlockable BIN1 mode where the actual pixel size of 2.32 is used instead of the OSC 4.64.

Good point - although the ZWO 071 camera uses quite an old sensor (IMX 071) it does have quite large pixels (4.78 micron pixels) and I have been impressed with it, despite the older sensor technology. However I am tempted at some point to move to the newer ZWO 533 camera. Matching the pixel size of the CMOS camera to your scope is well worth thinking about before you choose the camera.

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Well this was 3.5 hours of 5 min subs, under a moonlit sky and Idas P2 LP filter..with my QHY268c, at f5.3 450mm fl, there was nothing showing on individual subs, they were just a light green colour with the stars…I would have expected to see more in the individual subs really… but maybe that was the moons doing. It is very noisy…🤔🤔

I used the high gain mode at gain 0 on this camera which is unity I believe…

 

291EE681-4FF0-4BE6-8286-6F22B90C32A8.jpeg

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53 minutes ago, newbie alert said:

Atik already produce camera's with cmos sensors.. as do starlight xpress...

Atik are working on new technology  all the time as I'm sure starlight xpress do...

Note how they pic out what sensors the want to use and just run those, rather than having a massive portfolio of products that get superseded all the time.. great to see they use the imx571 sensor..

Where are there IMX571 based cameras, I’ve not seen those…?

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1 hour ago, centroid said:

That is something that I was not aware of, and good to hear. 🙂

I would love to support Atik or SX British designed and built CMOS astro cams, even though they will likely be more expensive than those emanating from China.

As you imply, there is a greater variety of Chinese (Touptek and ZWO) cameras,  than you can "shake a stick at". 

I guess more about grabbing a bigger slice of the market, than producing a smaller range of "ideal for purpose" cameras.

I wish Steve Chambers (Atik) ,and Terry Platt/Michael Hattey the best of luck with their new venture. I will watch their progress with great interest.

Atik and starlight xpress make quality camera's, not quantity some therefore the price is a bit higher.. also atik are made in Portugal,  not China so you would expect the price to be abit more.. much more to a camera than just the sensor

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2 hours ago, centroid said:

 

Imaging with the CMOS astro cam, I have found very different to CCD, and nowhere near as user friendly. Gain and black level setting, severe amp glow/starburst, and poor colour balance (green tint). Taking an image, checking the Histogram, makes setting the black point relatively straight forward, although I discovered that you need to do this for each exposure length, which is a bit of pain. I discovered this when I set the black point for a batch of 15s subs on the core of M42, and then using the same black point setting for the 90s subs, the subsequent Histogram showed the black point was way off optimum. Never had to concern ourselves with a black point setting with CCD.

 

But I'm sure you vary the iso when doing your day time photography and wouldn't want to be without that option!  The 294 has the benefit of that magic "high conversion gain" at a gain value of 120.  At this gain you have the same dynamic range as a gain of 0.  You just have a slightly lower full well.  You won't go far wrong if you always stick with a gain of 120.  Some people shooting broadband opt for zero gain in the belief that it can give a better appearance to broadband stars but this is probably dancing around on the head of a pin.  I use an offset of 50 and my subs are always 5 mins.  With CCD cameras I used to use the CCDware optimal exposure calculator to determine sub exposure time because you really didn't want to have subs longer than necessary. With my 3 cmos cameras regardless of optics I nearly always use 5 min subs with possible exceptions such as M45 and M42.  I take an initial sub to check I'm not blowing out my brighter stars.  You should be fine using an offset of 50 regardless of exposure time.  The "optimum" offset does vary if you change the gain value but the loss of dynamic range from an overly high offset is incredibly small.  You can tie yourself in knots with all this stuff but it just isn't necessary -gain 120, offset 50, cooling -10 (no good reason for going lower and kinder on your chip than -20).  Match your dark frame exposure time to your lights (uncheck any optimisation of darks boxes)  Flats somewhere between 25 and 30K ADU and take flat darks (dark frames which match the exposure time of your flats.)  Don't worry if your flats look dodgy it will all come out in the wash!  Re green cast, I prefer to correct this with levels since I think HLVG will shift some of the green across to other parts of the spectrum which isn't really an ideal way to treat linear data.  The HCG switch really changes the game, things are a bit more complicated with an ASI 1600.  

If you are in the Peak District let me know, I could ride over on my bike for a meet up.  We are off to the Yorkshire Dales later this week.

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45 minutes ago, MartinB said:

But I'm sure you vary the iso when doing your day time photography and wouldn't want to be without that option!  The 294 has the benefit of that magic "high conversion gain" at a gain value of 120.  At this gain you have the same dynamic range as a gain of 0.  You just have a slightly lower full well.  You won't go far wrong if you always stick with a gain of 120.  Some people shooting broadband opt for zero gain in the belief that it can give a better appearance to broadband stars but this is probably dancing around on the head of a pin.  I use an offset of 50 and my subs are always 5 mins.  With CCD cameras I used to use the CCDware optimal exposure calculator to determine sub exposure time because you really didn't want to have subs longer than necessary. With my 3 cmos cameras regardless of optics I nearly always use 5 min subs with possible exceptions such as M45 and M42.  I take an initial sub to check I'm not blowing out my brighter stars.  You should be fine using an offset of 50 regardless of exposure time.  The "optimum" offset does vary if you change the gain value but the loss of dynamic range from an overly high offset is incredibly small.  You can tie yourself in knots with all this stuff but it just isn't necessary -gain 120, offset 50, cooling -10 (no good reason for going lower and kinder on your chip than -20).  Match your dark frame exposure time to your lights (uncheck any optimisation of darks boxes)  Flats somewhere between 25 and 30K ADU and take flat darks (dark frames which match the exposure time of your flats.)  Don't worry if your flats look dodgy it will all come out in the wash!  Re green cast, I prefer to correct this with levels since I think HLVG will shift some of the green across to other parts of the spectrum which isn't really an ideal way to treat linear data.  The HCG switch really changes the game, things are a bit more complicated with an ASI 1600.  

If you are in the Peak District let me know, I could ride over on my bike for a meet up.  We are off to the Yorkshire Dales later this week.

Indeed yes, I do vary the ISO, so I see where you are coming from.

One of the first thing I did with the 294, was to run a sensor analysis in Sharpcap, which showed the gain v read noise optimum gain setting was around 900 in Sharpcap equal to a settting of around 9 under ASCOM control.

With the black level, I like to leave small gap on the Histogram, from the black end of scale, to where the image data starts. This is to ensure that the black end is not 'clipped'. I find that in general, a black point setting of around 30 is about right, but having now discovered how much this varies with exposure length, I will need to check the Histogram, whenever I opt for a different exposure length.

Interesting that you are using  5min subs with your CMOS cameras, whereas from what I see on forums, people are using much shorter exposures.  5 min subs I commonly used with my SX CCD cameras, occasionally 10 mins.

All of my 294c subs are taken at -10, and I have light panel for flats. One of the Kids bought it as a present at Christmas. Kids I call them, they are both in their 50s 😅.  25k to 30k ADU is what I used with my CCD cams. A sheet of white A4 printer paper over the light panel, which was not variable, did the job perfectly. The new panel has a variable output.

I will look closely at the HLVG results, and if I see the problem you describe, I will switch to levels.

When we will be up in the Peaks again I don't know. Nothing planned, but it will happen. I believe that it is not unknown for you to visit my part of the world (East Anglia), at least the North Norfolk Coast that is. We are down in 'Constable Country'  (South Suffolk/North Essex border), but do visit North Norfolk in the Motorhome.

Anyway, onwards and upwards with the 294c, but not tonight. Clear skies, but a full Moon.

Edited by centroid
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In the interest of honesty, as I have extolled the virtues of SX CCD cameras. although the MX5c, and the two H9's were faultless, the SXVR H16 wasn't.

It suffered from a light leak, and the camera was not efficiently dissipating the heat from the Peltier Cooler.

The light leak was resolved by SX supplying a rubber gasket to go between the nosepiece, and the camera body. The blue ring that you can see in the photo (circa 2012)

Their solution to the heat dissipation problem, was a bolt-on external fan, which as I remember retailed at £40 😮.

So I bought a mini 12V fan, fashioned an aluminium bracket, and sprayed the bracket black. Almost a carbon copy of the SX one, but cost way under a tenner. I set the fan direction to draw the heat away from the camera body, which stayed lovely and cool. Before you ask about vibration, there wasn't any.

Other than that, its was an excellent camera, and produced great results. I wish I still had it.

SXVR-H16_with cooler.jpg

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2 hours ago, newbie alert said:

... much more to a camera than just the sensor

This is true 🙂 

@centroid I notice you are critical of your camera but don't mention which brand you own. Instead you simply say 294 or 294c, as though all cameras with the same sensor are equal. Cameras that share the same sensor do have similar characteristics but their design, manufacture and performance are rarely equal. 

HTH,

Steve 

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1 hour ago, centroid said:

I

Interesting that you are using  5min subs with your CMOS cameras, whereas from what I see on forums, people are using much shorter exposures.  5 min subs I commonly used with my SX CCD cameras, occasionally 10 mins.

I've just been back over some images I've taken with the 294 and I had forgotten that I have previously used 10 mins for NB.  Would be quite happy with 5 mins and less.  The reason I don't go as short as possible is to avoid having huge stacks of files to plough through!  PI's weighted batch processing script stores all the files created at every stage of calibration, that's a lot of time and Gbs!

There is no great merit in taking the shortest subs required to overcome the read noise so long as things aren't getting blown out.  Each to their own but I am very happy with the results I'm getting.  

 

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11 minutes ago, FLO said:

This is true 🙂 

@centroid I notice you are critical of your camera but don't mention which brand you own. Instead you simply say 294 or 294c, as though all cameras with the same sensor are equal. Cameras that share the same sensor do have similar characteristics but their design, manufacture and performance are rarely equal. 

HTH,

Steve 

OOh yes, very true.  mine is a ZWO 294mm

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The length of time you can go with your subs with a CMOS camera depends on how dark your skies are - if you have very dark skies, then 5 or 10 mins are fine. For most of us with light polluted skies, you are better off with shorter subs, since you are picking up light pollution from the sky background. Also the other rule of thumb is that the narrowband filters usually need 3x the length of subs compared to standard UV/IR filters. So if you're doing 5 mins with a narrowband filter, you really shouldn't be doing any more than 90 secs with just a UV/IR filter. There is a very good video (from Robin Glover) on YouTube and there are Excel spreadsheets around in which you can input your camera, your settings, and sky background, and it tells you the optimum length subs to use. I find stacking a few hundred subs is quite quick in DSS - although it appears other software is not as quick.

Obviously you can use the preview screen to check you are not overexposed with the sub length, gain settings etc that you use.  

The other benefit of using shorter subs is there are less that have satellites flying through so you have fewer to throw away, and some people with lower level mounts may prefer shorter subs to avoid guiding issues. 

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59 minutes ago, iantaylor2uk said:

The length of time you can go with your subs with a CMOS camera depends on how dark your skies are - if you have very dark skies, then 5 or 10 mins are fine. For most of us with light polluted skies, you are better off with shorter subs, since you are picking up light pollution from the sky background. Also the other rule of thumb is that the narrowband filters usually need 3x the length of subs compared to standard UV/IR filters. So if you're doing 5 mins with a narrowband filter, you really shouldn't be doing any more than 90 secs with just a UV/IR filter. There is a very good video (from Robin Glover) on YouTube and there are Excel spreadsheets around in which you can input your camera, your settings, and sky background, and it tells you the optimum length subs to use. I find stacking a few hundred subs is quite quick in DSS - although it appears other software is not as quick.

Obviously you can use the preview screen to check you are not overexposed with the sub length, gain settings etc that you use.  

The other benefit of using shorter subs is there are less that have satellites flying through so you have fewer to throw away, and some people with lower level mounts may prefer shorter subs to avoid guiding issues. 

Hmmm, I am not sure about all this, as now the latest CMOS cameras are 16 bit, I was under that impression that longer subs would get better results from these, I have the QHY268c and tried 2 min subs, and got barely anything at all, just a boat load of noise….then as above I shot 5 min subs and still a boat load of noise, and this is with unity gain, and bortle 6 skies, and using an Idas P2 LP filter….at f5.3 with a tak FSQ85…

So I am confused by all these different opinions….on long or short subs….🤯

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59 minutes ago, FLO said:

This is true 🙂 

@centroid I notice you are critical of your camera but don't mention which brand you own. Instead you simply say 294 or 294c, as though all cameras with the same sensor are equal. Cameras that share the same sensor do have similar characteristics but their design, manufacture and performance are rarely equal. 

HTH,

Steve 

Its not a secret Steve, its a Touptek with an Altair badge.

I have seen green tinted images mentioned, and starburst mentioned with the ZWO equivalent, that of course  is down to the sensor not the camera manufacturer

I have been told by users, that the Starburst is the same with both variants, the only difference is the amp glow in the top bottom rails of the frame with the Touptek, that is not there with the ZWO.

Then I have seen a report of sealant leaking  onto the sensor window with ZWO, but not with the Altair/Touptek. But that doesn't mean that it hasn't happened  with the Touptek, but I have not yet seen reports of it.

I am an end user, not a seller of either brand, so I do not defend or recommend either. I just report what I find, and what I see reported by other users.

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1 hour ago, centroid said:

In the interest of honesty, as I have extolled the virtues of SX CCD cameras. although the MX5c, and the two H9's were faultless, the SXVR H16 wasn't.

It suffered from a light leak, and the camera was not efficiently dissipating the heat from the Peltier Cooler.

The light leak was resolved by SX supplying a rubber gasket to go between the nosepiece, and the camera body. The blue ring that you can see in the photo (circa 2012)

Their solution to the heat dissipation problem, was a bolt-on external fan, which as I remember retailed at £40 😮.

So I bought a mini 12V fan, fashioned an aluminium bracket, and sprayed the bracket black. Almost a carbon copy of the SX one, but cost way under a tenner. I set the fan direction to draw the heat away from the camera body, which stayed lovely and cool. Before you ask about vibration, there wasn't any.

Other than that, its was an excellent camera, and produced great results. I wish I still had it.

SXVR-H16_with cooler.jpg

I still have my old Atik 4000 mono, as been trying to sell for a while with no interest, I may well now keep it as a back up if I get fed up…with trying to get my head around this CMOS era….😂

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11 minutes ago, Stuart1971 said:

I still have my old Atik 4000 mono, as been trying to sell for a while with no interest, I may well now keep it as a back up if I get fed up…with trying to get my head around this CMOS era….😂

The lack of interest in the Atik, probably down to the fact, that most of the 'old timers' either still have their ccd cameras, but have moved to cmos, and the newer generation of imagers,  have no experience of ccd, so buy the now widely available cmos cameras.

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1 hour ago, Stuart1971 said:

Hmmm, I am not sure about all this, as now the latest CMOS cameras are 16 bit, I was under that impression that longer subs would get better results from these, I have the QHY268c and tried 2 min subs, and got barely anything at all, just a boat load of noise….then as above I shot 5 min subs and still a boat load of noise, and this is with unity gain, and bortle 6 skies, and using an Idas P2 LP filter….at f5.3 with a tak FSQ85…

So I am confused by all these different opinions….on long or short subs….🤯

What acquisition software are you using? I tend to use the ASI Air Pro, and the images you see on the screen are automatically stretched, so the object would have to be very faint not to show up on the screen.

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