Adam J

Just use a pier extension when using the refactor. I would not change the height of the main pier. I hope that there are still some darks skys left for me when I retire in 20 years time.

Having used that stuff you don't have much time before it starts to go off so you will need to work fast. Will you be leaving the mount outside on the pier covered? or taking it out each time you image? Adam

Rob I have looked at this a couple of times over the last year and I always wonder how you control camera rotation with this setup. Also how do you colimate?

I would think that FLO will sort you out especially as you have not even opened the box. Consider a Ha filter too when you can afford one. You will still need something to hold that 1.25 inch filter in as the camera wil connect to your corrector via T2 threaded extenders. You need to keep the FF/FR to sensor spacing at 55mm for it to work. Adam

Understood, but I dont think it will be much of an issue with the OPs 80mm F6.3 refactor. With mono you can chose to refocus per filter, with OSC you dont have the ability to refocus for each wavelength as such not refocusing a Mono camera will deliver similar results to the OSC. The most important thing to focus on with mono is the lum filter as that determines the sharpness of the image, RGB filters just add a colour layer.

Your points are valid, OSC is less effort in capture and requires less experience in processing, but I dont see why you would want an auto focuser. I have dont have one. You dont have to go mono, but it will perform better, especially in light polluted conditions.

As I seem to have given you cause for doubt ill try to address some of your questions. I will start by saying that I will stand by my original advice that in a light polluted environment mono is best. Its best because you can use that 1.25inc CLS CCD LP filter as luminescence and then gather RGB allowing you to mitigate light pollution without messing with your color balance. Using luminescence you will collect data about twice as fast as you would with the same chip in OSC. You can also bin effectively and you will retain the full resolution when imaging using Narrowband filters as they will make use of all pixels and you wont lose OIII signal as it falls between the pass bands for Green and Blue. I am in a Class 4/5 area and I would not be without my mono camera. I imaged with a cooled DSLR for a while while I was saving up for it but I am happy I waited. The only way to effectively image on moonlit nights is to make use of a Ha filter and that will work best with a mono. You can use a Ha filter with OSC but it just wont be optimal and I would have to wonder why would you buy a new OSC and then immediately put a ha filter on it, that makes not sense. In terms of suitability with your scope, start by looking here: http://www.12dstring.me.uk/fovcalc.php You will get 1 arc-second per pixel with the 0.85x reducer, that is within the recommended 1-2 arcsecond per pixel range. As such you will be aperture limited in terms of resolvable detail as the daws limit of the scope is around 1.6arcseconds. But as its a mono camera you can effectively software bin 2x2 to give you 2 arc-seconds per pixel and that is pretty much where I would want to be with your scope. The ASI1600mm pro would be a better option at that focal length as its a larger sensor and more optimally sized pixels meaning you would not need to bin, however its outside of your price range. So given the options available ASI294mc pro or ASI183mm pro I would go for the latter. With any set point cooled camera you can take your dark frames at any time even inside if in a dark room. To get running without blowing the budget you would need a manual filter wheel (although a 5-position electronic wheel is not much more and much more user friendly) and a LRGB filter set. You can use your existing LP filter in place of the UV/IR cut. So CLS RGB as opposed to LRGB, if the CLS filter is the same brand as the LRGB set then you may not need to re-focus between filters. You would also need spacers to make up the correct back focus taking into account the 6.5mm for the camera and 20mm for a ASI wheel. With less light pollution the ASI294mc pro is a great camera, one of the lowest read noise OSC avaliable. You could chose to buy a STC Duo narrow band filter for use on emission nebula with the ASI294mc pro (although they are so expensive and still not as effective as separate narrow band filters!) The main issue is with Galaxy imaging as once you introduce a strong LP filter in front of an OSC you are damaging colour balance. In my opinion the only real marks against the ASI183mm pro are that you need to take care with calibration (same with ASI294) and that in comparison to the 294 its a smaller sensor so you will have a smaller field of view and with the smaller pixels longer exposures (5mins or so) are advisable in comparison to the 294mc pro, with your scope I would also bin 2x2. You dont have to go mono, OSC is less challenging in terms of calibration and integrating multiple channels, but if you really want top end results then mono is the way to go. So really this is a question of how seriously you are wanting to take the hobby and what results you will be happy with. There is no point in going mono if it sucks the enjoyment out of it for you, but if your like me then I would always be wanting to take the best images I can on my budget and am willing to work for it. The ASI294mc pro is not a huge mistake, its a great OSC if that is what your looking for in your imaging. Its just that with a little more effort in capture and processing the ASI183mm pro will deliver you a better quality image in your sky conditions. My final advice is that given the time of year dont let a couple hundred pounds stand in the way, just save a tiny bit longer. Summer is not the best for astro imaging anyway and if you do decide to change the camera then its ok to change your mind,just dont forget the original reasons why you chose the ASI294mc pro in making that choice. This chap is one of my favorite imagers and I follow him on astrobin. Most of his stuff is taken using the ASI183mm pro. https://www.astrobin.com/users/GerminianiMaicon/ Above all stop stressing. Adam

So I decided to place a aperture mask over my 130pds primary mirror, I did this so that I would get tighter better star halos without the very edge of the mirror (usually the worst part of the grind / polish) and without the mirror clips. The mask is 123mm in diamiter meaning that I loose 6mm of mirror (yes 6mm) as the 130PDS has a 129mm mirror if you measure the thing. When taking into account my coma corrector (TS Max Field) that has a reduction factor of 0.95x leaving me with a focal length of 618mm this gives a F-ratio of F 5.02 so back where I started before masking when i used to use a Baader MPCC MK3 Following initial testing I am pleased with the results with bright stars in luminance being much more tidy. I also blackened the edges and bevel on my secondary mirror. Ill post some comparison images when available. Adam

Depends really as astro twilight can actually be of lesser effect than the local light pollution in some cases.

I am very tempted by a Sharpstar 86Q, its on my short list of scopes for when I finally get the cash together. Example images showing corner stars would be appreciated.

Was thinking of OIII but thats 8.5nm isnt it. I think the new baader Ha is 3.5nm

Would be interested in AD 5nm vs Baader 4.5nm vs Baader 7nm if possible with regard to reflections more than anything else. Adam

Is the pole actually on your land, that is unusual.

It sounds to me like they meant chips as in a sub category of CCD and or CMOS as there are a number of new generation CMOS chips coming to the marked in 2019/2020 that are worth waiting for, as an example several manufacturers have full frame mono CMOS chips on the horizon, as soon as summer in fact. It seems less likely to me that they meant a new technology. If such new technology did become available I doubt we would be the first to see it used in our amateur astronomy cameras. Adam

this is useful:

My impression is that the Stellermate is harder to setup and get working than the ASI AIR which is a little more plug and play. Since the issues you are having are to do with inexperience (no offense) I think that you might be swapping one confusing system (ASCOM) for another in Stellermate. The ASI AIR will only work with ASI cameras and guide cameras. So you would need to purchase a ASI120mm guide camera if you wanted to go that way.

I am not sure that you can use a normal reducer on a four element design as you would end up trying to correct for curvature in a scope that has already been corrected inducing aberrations as opposed to removing them.

The thing to remember is that while not very narrow the original 7nm / 8nm Baader filters are not bad filters by any stretch, they have reasonably good coatings etc. So if these new filters are better still it will start to cut into the AD marked given how much they have increased their prices.

Ill be getting a SII 4.5nm as the price increase for AD 5nm filters and the amount of time ill actually spend using a SII filter in comparison to OIII and Ha means its just not worth it to me.

Thinking about it, one other thing that would be of use is to know the dark current.

exactly..

To be honest no it makes no sense,the IMX290 certainly does not have a 3e read noise at unity...they are implying that these are three almost identical chips in terms of read noise and that's just not the case. So when they say it reduces to 1.5e which one is that, all of them? The information on @FLOs web site for this new camera is very poor in comparison to other CMOS sensor cameras that they also sell. SX make claims about amp glow so a 15min dark frame to back that up would be great. Also as above, at the very least I want to see some gain vs read noise vs dynamic range curves..etc. I would also like a QE chart. Its a specification that is almost identical to their CCD cameras, problem is that is not the level of information you require for a CMOS camera with variable gain etc. Also at 2200 pounds it had better perform very favorably in comparison to the ATIK or ASI offerings. I just feel its asking a little too much when pitched against some of the competition. It may well justify its price if it performs but More information required to make that judgement. Currently anyone buying this is buying it blind. If I could try before I buy then no problem but this is a totally new sensor to the astronomy market I will be wanting more than the basic information of FLOs web page to make a decision to jump in as a lead customer. For example If you look at Sonys tech documents then the max exposure for the IMX304 is 30seconds, at the moment they are implying at least 15 mins but there is no specification for max / min exposure even. It always difficult with totally new products, someone has to take the leap first, but hopefully FLO can extract some more information from SX to help people make an informed choice. Adam

They dont give much away,I want to see some gain vs read noise vs dynamic range curves. Also at 2200 pounds it had better be spectacular....3e is high read noise for CMOS.

wow I would not have thought it possible, was it a dust devil or something?

looks like the core of M42 to me Rod....