Adam J

Awesome, what i would not give to have such dark sky. Adam

No it wont work like that, one filter will block the other and vice versa. Got to use them one at a time. I have no idea why anyone would want to stack filters for imaging.

Guess i am confused by this as I took a set of darks about two years ago and have never had to take another.

Everyone uses this example and every time I say it's a huge sensor with pixels the size of dinner plates better QE than any mature sensor on the market and cryogenic cooling. That's why it overcomes F10. If you stick a asi1600 on it do you really think you would get this result with 2min subs?

If you need to crop it out after calibration you are calibrating incorrectly.

The Panasonic chip is still a good OSC its not as fast as the IMX294 but it calibrates better and so when it comes to very faint signal it will show a better background when imaging galaxies in optimal low light pollution conditions in comparison to the IMX294 which has some very very faint residual background artifacts after calibration. However, this is less of a consideration with nebula imaging when the IMX294 will be the best choice. Its worth keeping the IDAS for galaxies etc if its working for you already, but I would 100% pair the new camera up with a duel narrow band filter to make the best from your LP conditions with an OSC (Duel narrow band is for emission nebula only not for galaxies). If I was close to London though I would focus my effort on emission nebula as opposed to struggling with galaxies. Adam

I have recommended the 460EX to a number of people recently, but the amp glow on the ASI1600mm pro is one of those things that makes people fear until you own one and realize its no problem at all is certainly not the reason to chose the 460EX over a 1600. The real reason to do that is the micro lens diffraction issue. The big reason to chose the ASI1600mm pro over the 460Ex is purely sensor area. Sensor area is more important than people think sometimes because it means that you can use a larger aperture at the same f-ratio while maintaining field of view. So a 80mm scope at F5.5 with a ATIK460EX has about the same FOV as a 110mm scope at F5.5 with a ASI1600mm pro as a result you can down sample the image on the ASI1600mm pro image by a factor of 1.66 to the same image scale as the 80mm and ATIK460ex combo gaining significant signal improvement at the same FOV.

I think that lum will help personally i would say that proper luminescence is the way to go here, the dust is reasonably balanced between R,G & B channels so will benefit fully from using a lum filter.

You just need a set of darks for the amp glow, I have never used anything other than 60seconds for LRGB at gain 76 and 300seconds for Ha, OIII at gain 139. Hence I need two sets of darks for all my imaging. reflections of thr ASI1600mm pro are its only real problem. I normally say go mono, but if your only getting in 8 or so imaging sessions per year then I think i would actually just go with a OSC sensor at that point as imaging is clearly something your dabbling in as opposed to being your main hobby. Getting an OSC like the Atik Horizon OSC or the ASI294mc pro or the QHY168c along with one of the new duel channel narrow band filters will give you a result in a single night every single time without needing LRGB Ha OIII SII filters flats for each and potentially focusing for each dependent on your scope. My only concern is that your in London......do you know what your sky brightness is? If its outer london they you may get away with a duel-band filter, certainly not tri-band or quad-band. If your really into the light pollution though it is mono with separate filters or nothing. Also anyone who is willing to take images over multiple nights should always be going mono. But if you want to image once a month and you want a image in one night every time OSC really is the way to go especially with the weather we get in the UK. Adam

No the other way round a duel band is most effective at blocking light pollution.

Yet the larger sensor is a huge advantage. Nothing is faster if you need to take two panels to cover your target. For smaller objects though its makes more sense to want to go with the smaller sensor.

I am not sure on that one but what I am sure on is that the ATIK460ex now sells second hand for around 900 - 1000 pounds on ABS and here. The ASI1600mm pro will sell second hand for around 800 - 900 pounds. Recent examples on here and ABS being one of £900 and one for £999 people have tried selling them for £1100 but they have not sold. So in the case of the ATIK460ex its selling for around 45% of its new price. On the other hand the ASI1600mm pro is selling for 65% of its new price (about the standard for astro equipment). So that tells me that the ASI1600mm pro is currently a more in demand camera by far than a Atik 460ex when sold second hand despite the apparent bargain prices that are coming up. Adam

Under those sky's you will want a very narrow filter for nebula. Star clusters are bright and galaxy imaging will be a challenge irrespective. I would just go for a nebula filter as trying for best of all worlds will not work out well. Hence I would recommend a duel band filter, Tri band at a push.

I would say that you will have issues with the ASI294mc pro, if it was that easy then no one would be paying the big bucks for a FSQ-85, I have seen someone use the 0.6x reducer with a very small sensor, something like a Atik 428ex sized sensor to gain a larger field of view and it just about delivered a flat field on a sensor that size. I dont see there being any chance of it delivering for you with a sensor the size of a ASI294mc pro though. Adam

No its the other way around the shiny side on the female side of the filter cell is not AR coated the other side with the male thread is AR coated. The main issue AR coatings are trying to prevent is reflections back towards the filter from the sensor itself.

get one of these and stick it between the corrector and the wheel. https://www.firstlightoptics.com/zwo-accessories/zwo-m42-m42-extender-21mm.html it will leave you 0.5mm too long but that is within tolerance. Adam

No, see above, and its actually 12.5mm back. and you measure from the rear of the corrector not the centre. As shown in your image your spacing is currently 36mm assuming the ring that comes with the corrector is tight onto the corrector, if not then the measurement will be off. Adam

No its not the centre of the coma corrector is the rear mating surface of the coma corrector to the sensor. So: Sensor - 55mm - Coma corrector rear surface (the ring just after the T2 thread)) Not: Camera - 55mm - centre of the coma corrector. Hence you need to know the depth of the sensor within the camera from its mating surface, in your case thats 12.5mm Hence Camera = 12.5mm Male to male T2 converter - 2mm (assuming its the ZWO one) Filter wheel = 20mm That totals 34.5mm and so you need an additional 20.5mm of T2 spacers between the filter wheel and the back of the corrector. Adam

Actually as its so close to the optical element and further spaced from the sensor then it would be in a wheel you might actially want to use it that way around anyhow as that way the AR coating is pointing towards the optics. Usually the other way but here I think the normal rule may be reversed. Adam

That improved the second one but I think the blacks are looking a little blue at least on my monitor.

First things first I would cool the camera while observing the sensor (dont do it in the house do it outside) if it fogs up then you will see it happen. If it happens then try cooling slower using the settings in APP as larger sensors like this one do in general need to be cooled slower anyway. Dont go messing with the descant until you have tried this. If those things do not help then its time to try recharging the desiccant. From that point on I have no practical experiance as my ASI1600mm pro has never required this. I know that there is a round black sticker on the side of the camera and that if you remove it you will find a screw cap and that the desicant tablets are here. Tape over the hole while the camera is left open. Its then a matter of drying them on a clean baking tray in the oven for a few hours. Dont try to microwave them. I would try a temperature of about 120 degrees Celsius. Adam

In respect to a single batch of bad cameras I feel this is just par for the course with the ASI071mc pro I think that on this sensor the QHY version is superior, it never experiences these issues. In the end the reason is that for such a large sensor its not appropriate to place it so close to the optical window. Cooling slower is the best bet, if that does not work then you will want to re-charge the desiccant as mentioned above. Adam

Looking good in terms of signal but i would process it differently almost like you process separate Ha and OIII data. Its possible to extract channels and reasign them to different colors so if you want the more classical electric blue look as opposed to green then you can separate the channels process each channel and then re-integrate them. Its actually something that you need to do to get the most from a filter like this as in lots of nebula is you dont then the OIII will get buried under strong Ha signal and you will get very little color variation in the image. Adam

I would not bother assuming you have already got an outside power socket. Its a 1 min job to run an extention to the pier.

I have half a memory of someone selling an filter adaptor to accomplish this. Filter rings are not really structural and I would not recommend using the as a spacer.