Adam J

I have a 15volt power supply, measured it before using it and it came out at 16.2volts. I would leave a margin for error.... Adam

So what I will say is that you have now posted a large amount of information that you did not include in your original posts. I had also worked out the 18% but the thing is in most cases people over expose anyway and so unless you are keeping your exposure as short as possible you will probably never notice as you are likely to be above the required exposure in either case for the read noise difference to have no effect on a stacked image. For example when you look on astrobin most people are taking 300s or similar exposures, way longer than required and producing fantastic images. So unless you are wanting to use 20second exposures and moving to 24second exposures is a problem for you, you are just not going to notice it. Also important to remember that's 18% more sub exposure not 18% more total exposure. The main thing that drives my exposure time is not trying to get the shortest possible exposures for my read noise and sky conditions but more that I don't want to be dealing with 1000s of subs. My guess is that playerone have taken 20 cameras tested them and presented the best results. Sensor to sensor variation is a real thing. Can you post a dark frame? The general issue with this type of sensor measurement is that the stats can be effected by a small number of bad pixels that in practice calibrate out, although I don't know the exact method used by Dr Glover to potentially reject these. Perhaps you could find someone with camera and the same sensor to make a comparison with. You may have said above but have you tried a different capture program? Try not to dwell on it and be too disappointed. It's still going to take great images in the right hands. My experience is that one of the biggest factors in end image quality is the imager themselves. Adam

Yes his worry is genuine but that doesn't mean he should be worrying about 0.1e of read noise or less by your own estimate. The maths just doesn't support that, 0.1e is not going to have a real effect in integrations especially for long exposure DSO imaging. When I have time I will come back and prove to you with some modelling that 0.1e read noise simply has no effect as the other noise sources are more significant. As above this is certainly withing normal variation from sensor to sensor. But if you don't believe me then take a look at Doctor Robin Glover's (yes the man behind sharp cap) presentation on read noise from the 2019 practical astronomy show, it's on you tube. You would spot the back of my head in the audience if you knew where to look. One of his conclusions is that read noise is so low in general in modern sensors that it is no longer a significant contribute to overall signal to noise ratio, so long as your exposures are not crazy short like 10seconds for braud band. here is a link: 39mins and 30 seconds shows the effect of read nose from different cameras on overall signal to noise. 46mins companies 2.5e read noise to 7e read noise and basically even for that huge difference you get the same signal to noise as long as you expose for 120s or more. In the end it's just not going to make much difference and it might not even be a real difference at all. Just a difference in how read noise is being calculated. For example outlier handling of hot pixels etc. For short exposure stuff like solar system imaging it will matter more. But the IMX533 is more often a DSO camera. Adam

IMX472 would be the current closest candidate but I would think it's only a matter of time really. Adam

So first thing first. Are you aware that ZWO and Player One also ( unless I am mistaken) do not use Sharpcap for their chart generation. So what you have is three different measurement methods in play here. I think playerone have chosen a more generous method of measurement as your figures are not far from the ZWO figures for the ASI533mc pro. You say 1.38e at gain 200 7k full well. ZWO are saying about 1.3e at gain 200 and 5k full well. So a little lower but at what looks like slightly higher relative gain. Now these difference between Normal read noise and LRN mode are small as things go at unity gain you are talking about 0.11e between the two modes. I would expect the read noise variability from sensor to sensor to be larger than that tiny difference. If it was my camera the difference between 1.38 and 1.5 would not bother me at all and you won't visually detect it in your results that's for sure. But as above I think the bigger issue is you are comparing apples and oranges if you are looking at those charts and expecting them to perfectly match results from sharp cap. So I think you should stop testing the sensor in sharpcap and take some images with it. There are many other sources of noise beyond read noise that everyone forgets about and added together make your little differences in read noise insignificant in terms of total noise. Just expose very slightly longer if it is really eating away at you and your will have negated the effect anyway. This is a panic over nothing. Go take some images. 🙂 Adam

Since when is 1.86 under-sampled and why don't you just software bin the 183 in processing? Adam

FRA300 would be my choice. Spot diagram says it all.

Yes but the point is that it is a physical measurement from one point to another that changes when you add a filter.

Depends on if your frame of reference is the mechanical path length or the optical path length. As we are talking about spacers and the physical position of focus changing we are talking about the mechanical path length between the objective and focus and that has changed. In fact both have changed, the thing that has stayed the same is the F-ratio of the system as the angle of the light cone is the same. Its a bit like how some corrector designs with also change the position of focus and hence the mechanical path length. However, looking at the definition on Wikipedia the focal length is defined as the physical distance between the focal plane and the principal plane of the optical system and so I am going to go ahead and say that the focal length has by this definition been changed by the addition of a parallel optical surface. Now if you want to talk about the focal length of the objective, thats the same, but we are talking about the focal length of the entire optical system including filters and corrector and cover-glass etc.. Adam

Oh this one again. The mistake everyone makes is thinking that you need to move the sensor by adjusting back focus so that the sensor lays on the new focal plane as dictated by the added glass. This thinking leads to confusion. What you actually need to do is ensure that the focal reducer is on the correct part of the light cone when the sensor is in focus i.e you don't want the change in focal length to result in the position of the corrector changing. Hence the thing to remember is that the focal length of the scope is slightly extended by the introduction of the filter (and sensor cover glass that everyone forgets to add) so to keep the corrector in the same place as it is without that glass you need to add that difference in focal length onto the back focus quoted for the corrector. That distance normally being 1/3rd of the thickness of all flat glass elements in the light path between corrector and sensor. If none of that made sense stop thinking about it and just add 1/3rd the glass width to the back focus. You don't need to understand it for it to work. Adam

Shape of the heatsink cut away. Not sure on options for AA I know Rising Cam offer both. Adam

I would never consider anything but AR coated. Better to be in full control of what gets to your sensor. Looking at AAs 533m it is the newer version most of the other cameras are not pictured as such yet. Adam

Very nice, never heard it called the jelly fish before only the crescent nebula. Adam

Exactly can it guide with short exposures as required by some modern harmonic drive mounts while using a narrow duel band filter. I think that the AA will work out just fine. But I would make sure its the latest version as rising cam have a new version of their camera and it will inevitably filter down to the clones. Adam

The problems are inherent to the sensor not the camera it is placed in and so the 294 is going to be a pain irrespective of brand unless of course you happen to luck out and get a good one as the effect changes from sensor to sensor. Adam

When I am discussing backlash I am talking about a mm or two not a CM. The mechanism I am talking about above would not allow such a large amount of movement. You have a different issue possibly something wrong with the clutch or maybe the worm itself is moving laterally. Above is a tuning issue, what you have is a fault and not normal as Steve says. Adam

so fan won't start unless you have both power to usb an to 12 volts. check the usb cable and that the port it's plugged into can supply sufficient current. If you have other things on the same usb buss the can drain too much power, so unplug other devices.

just that you can get larger targets in the FOV at the same focal length. Adam

yes you can.

in what way is it not working for you? If it is working for you then....

yes that one and others come to mind.

I dont recommend using anything more than a UV/IR cut for galaxies and other baud band targets, has a bad impact on colour, in terms of emission nebula there are better filters available than a L-eNhance. Adam

Why would you not be able to use APP? Assume Astro Pixel Processor would work just fine with Rising Cam? Adam

I am off to Tenerife in two weeks to shoot this with the same scope and mount. Seeing whats possible from the UK gives me hopes of a good result. Adam

You would get as much additional FOV by selling the 533 and buying a rising cam 2600 equivalent and have more change left over than buying a redcat. Adam