centroid

EQMOD Malcom. Polar aligment hasn't moved. The mount remains on the pier, which is bolted to a concrete base. The mount and pier adapter, are each marked, so any movenent of the adusters, would be visible, as the marks would not be aligned. I always set the Meridian flip point with the NEQ6 a little way past the Meridian point, so the imaging run could continue on for a bit. However, this is not a Meridian flip issue. Starting a Goto from the Home position, to an object east of the Meridian, is fine, but going to an object west of the Meridian, is way off target. When I next get the chance, I will try to Plate Solve some objects west of the Meridian and sync the mount to them. It only needed to do thiis on a couple of objects on the east side, and east side gotos are fine. I find that plate solving struggles if the goto object is too far off target. I just need to "play" some more, but clear sky opportunities are infrequent enough, not be wasting them faffing around with equipment problems.

Maybe its me "not seeing the wood for the trees" here, but I have come up against a problem with the HEQ5 Back in the day (pre 2014) I was using an NEQ6 and never came up against the same problem. I think I was 'driving' it via ASCOM, but I can't remember. Was ASCOM control about then? I am Polar Aligned, and the mount stays on the pier so doesn't move between imaging sessions, only the scope is removed, and the Dovetail is marked, so the scope goes back in exactly the same position, thus removing the need to re-balance each time. I am driving the mount via ASCOM (EQdirect), which works fine for GOTO, and Guiding, but!!! However, if I have several objects, East of the Meridian, set as 'Sync' points, it remembers them, and can GOTO them again, so far so good. With the Meridian limit set in ASCOM, the mount stops there. If you ask the mount to go from an object East of the Meridan, to one West of the Meridian, it stops at the Meridian, and 'flashes up' a warning that the limit has been reached. Remove the Limit, and of course the mount will traverse the Meridian. However the selected GOTO object way outside the FOV of both the main scope, and guide scope.. Return the mount to the 'Home' position, and then GOTO an object West of the Meridian, and the object is still way off target, and too far off for Plate Solve (> than 15 degrees) to bring the mount onto the object. The difficulty is that I am controlling the mount, via Ethernet, from the summer house/shed some 6m away, so I can't look through the 50mm, or Red Dot finder, and then 'drive' the mount to the target, and 'Sync' it. It is so far off, that a circular search can't reach it.. Accurate East of the Meridian, but the accuracy does not carry through the the West of the Meridian. Any thoughts or suggestions would be most welcome.

No problem Steve. Its all interesting stuff, and I think my original post had a good 'airing', and had 'run its course' anyway 🙂

The "law of diminishing returns" Martin 👍

An interesting 'take' on the subject, and lot of which is probably very true. I had no understanding of CMOS sensors used in amateur quality astro cams. The choice was wide, too wide actually. My decision was based on sensor, and pixel size, plus cooling. It now seems there are far better choices than the 294 sensor, which I am told is quite old tech now. We live and learn. 🙂

I guess the CCD v CMOS contest is pretty much over now, and CCD for amateur astro is now dead , RIP old friend 😢. I have been looking at a multitude of CMOS images on the forums, and find that while there are some really excellent examples, there are just as many, if not more, that are way below par, at least to me that is.. It does show that in the right hands, these cameras are capable of returning good results, but how much of this is down to a good understanding of "the beast", and or, the processing skills of the imager. It is clear to me, that the CMOS camera requires a good understanding of its ability and quirks, far more so than CCD did. Definitely not 'plug and play' devices, no short cuts, we have to learn to work with them, and their quirks, to extract the best .

If nothing else, this has certainly proved to be a very popular subject, as of now some 652 Views, and 61 replies. At least is something to pass the time reading, while we sit under the first full moon of the year. 😉 I just went outside, and its high enough, and bright enough to read a book by.

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.

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.

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.

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.

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.

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.

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.

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.

Back in the day, it was not unknown for me to stay out in my then obsy, all night, but I'm not that enthusiastic now, and a lot older.

"I am sure you will learn to love CMOS in time Dave!! " I don't think that I have much of a choice Martin, other than go back to CCD, or give up 😅 I has been an interesting discussion, with some very useful input, your own included. I can't see me getting back into NB, or LRGB imaging again, I did that 'back in the day'. As I said previously, astro is now very much a secondary interest to my photography, which I can pursue, day, night, cloud or no cloud, and not be bothered the Moon 😀. I only came back into astro imaging, as it was an itch that never went away, and I needed to scratch it 🙂. Roger of course, also now a keen photographer (wildlife), has zero desire to return to astro imaging. I will be happy if I can get the occasional decent DSO image, with the CMOS OSC camera, to maintain the interest, and to justify the money I have spent buying new kit (I sold everything back in 2014). Now if only I had kept the SXVR H16, as an ornament or such like. ☹️ As you say, your 294 "does show some impressive amp glow", a bit of an understatement in "my book"😉. Having the TEC cooled model, it should not be a problem in matching the Lights, Dark, and Flats, although I have seen reports of it being somewhat difficult to eliminate in exposures over 240s. These CMOS sensors are very much re-purposed devices, never designed for astro imaging, as was the case with CCD in amateur astro cameras also, but the CCD, although less sensitive, coped far better. As least in my opinion. CMOS is great technology for digital cameras (terrestrial photography), and the CMOS sensor in the EOS 5d MklV is superb. I can photograph virtually noise free, up to ISO 12800. Would I hang it on a £1200 telescope, no way, too expensive, and far too heavy. The green cast, is as you say, apparently down to the RGGB matrix, and the lack of white balance I guess. However, it is easily removed using the "Hast la Vista Green" plug in for photoshop. It is early days yet Martin, and still enough winter nights left, to explore what the 294c is capable of, quirks and all. Then come the Spring, it will be time put it away, get the Motorhome out of storage, and get out and about again. Who knows, we might cross paths, when you are out and about with yours. The Peak District is very much a favourite of ours, and of course it is your part of the world.

Yes it is OSC Olly, and would never have bothered imaging DSOs in the presence of Moonlight. However, having returned to imaging at the end of last September, i have had to jump a number of hurdles, hardware, firmware, and software. After dealing with each one, this week was the first chance I have had to use the gear in anger, even if it was just a short test session. So, moonlight or not, I had to give it a go. Unlike my 'plug and play' CCD days, I have found the need to experiment with gain and black level settings. Thank goodness for the Histogram. Interestingly, having taken both 15s and 90s images, the blackpoint setting used for one exposure, was way out for the other exposure. Not a problem objects not requiring the combination of two different exposures, such as M42. Never a problem with ccd. I will give it a fair try Olly, but does seem from what I am hearing, the 2600 is a much better option than the 294.

Well spotted Dave 🙂. Yes it was the Kodak sensor in an SX SXVR H16, and of all the Sony sensor based cameras I had, up to H9 size, it was the best,. Far more hot pixels than the Sony ccd sensors, but easily removed in processing.

In fairness Lee, the 294c is the only cmos based astro cam that I have owned/used, and from what I read, the 294 sensor has been around for a whiie now, so almost certainly old tech compared to the 2600. Technology moves on at a pace, and with it things usually improve. Once I get to understand the 294 and its quirks better, I will get more from it. As you say, I can always go to ccd, but its early days yet.

An interesting input "whirlwind" thank you. It is very much a case of "swings & roundabouts", CCD has some very distinct advantages over CMOS in astro cameras. Much cleaner images, no quirky green colour cast, and no gain or black point to set correctly, but CCD is yesterday's technology, and more expensive. Plus the fact I seem to remember reading somewhere, that the failure rate in manufacturing the CCD 'wafers' was quite high. CMOS on the other hand, is by comparison, much cheaper to produce, and has huge market in the digital camera world, including in mobile phones. The amateur astro camera market is miniscule in comparison. As far as I can see, the main benefits of CMOS astro cameras, are lower cost, and greater sensitivity,. But, there is no such things as a free lunch", and the downside is, severe amp glow/starburst,and other quirks . As I understand it the amp circuitry is actually on the CMOS 'chip', whereas with the CCD camera, it is separate from, and behind the sensor. The 'bottom line' is that sadly CCD for this application is now a thing of the past, and like it or not CMOS is here to stay, so we have to work with it, until something else comes along. Fortunately for me, astro imaging is now very much a secondary interest to my photography. I have seen several very nice astro images produced with CMOS astro cams, but I think that is more down to the processing skills of the imager,. Conversely I have seen quite a few very garish one. Just for the fun of it, this afternoon, I had a 'play' with my image in the "digital darkroom". Heavily processed in both Photoshop, and Lightroom to produce this psychedelic result 😀. Albeit it did extract some more detail, but quite over processed, especially the stars. No darks or flats. In the mean time, I will give the 294c a fair 'crack of the whip' before making any decisions, and maybe, I might get to like it. 😉

That is a pretty good result Martin, especially with just 7 x 90s subs, considering the disappointing result that I got with double that number of 90s subs. In fairness, it was a bright moonlit sky, but I still would have expected better. M42 is hardly a feint object. I will give it another go when the moon is out of the way, and see what difference it makes. I have an adapter arriving from Germany on Tuesday, that will allow me to attach the WO variable Flatttener/0.8x reducer to the 115 f/7 Apo, which will speed things up a bit from f/7 to f/5.6. That said, call me a sceptic, but I still think that the CCD was much more 'user friendly. No severe amp glow/starburst, no black level, or gain setting to get right, no green colour cast, and no other strange colour renditions. I do see some very odd colour images posted, having been taken with CMOS cameras. Yes, I know they are cheaper, and more sensitive, but imo, compared to CCD, that is as far as it goes. However, it is early days for me with a CMOS astro camera, that use re-purposed senors, not designed with astro imaging in mind. I will see how it goes, and I can always go back to a loved, and trusted, Starlight Xpress camera. I note that FLO still has a good stock. Terry Platt of Starlight Xpress, always provided excellent customer support, with their manufacturing based in the UK, and not China.

The first astro image in the 8 years since I gave up the hobby, with a somewhat disappointing result Just a test run under a Moonlit sky, when I would not have normally bothered with imaging deep sky objects, but after weeks of all sorts of problems, both hardware, and software, I had to give it a go. Just 15 x 90 second exposures, combined with 15 x 15 second exposures, and processed in Astroart 8, and Photoshop. Way below the quality that I would normally accept, but a new type of camera technology for me. Whereas I used to use CCD based astro cameras, I now have a 294c CMOS based camera. More sensitive, and relatively cheaper than CCD, but they have some odd 'quirks', that take bit of getting used to dealing with. Yes, it could have done with a lot more subs, but even so a pretty lack lustre result, and one that I had to 'push' hard in processing the get that. I have included another image, of the same subject, that I took with an SX ccd camera, back in 2012. Early days yet, but the temptation to go back to ccd, while they are still available, is growing 😉

Thanks Vlaiv, very informative as always 👍 That explains why we see many odd looking colour images posted from CMOS colour astro cameras. CCD astro cameras may not produce colour equivalent to that of our DSLRs, but in my experience were quite acceptable. Certainly not the case with my re-badged Touptek 294c, but the colour I can adjust to suit.

Ah, that is probably the answer Vlaiv. The images were non debayered. I have another 'play' this afternoon. CMOS cameras do seem to produce same strange colours, compared to CCD. It has to be down to the camera processing, as my Canon EOS 5d MKlV is perfect, as were all my DSLRs, and all CMOS of course. Yes, I did copy and paste the post.