QSI 683wsg-8 CCD Camera w/8 Position Filter Wheel

[xelasnave]

I have been reading the various cameras available at Bintel and this one, QSI 683wsg-8 CCD Camera w/8 Position Filter Wheel, seems rather decent.
It seems to have guiding built in which seems like a good idea plus the filter wheel comes with it...I expect you need to buy filters however, but it is a CCD which some say is better than a cosmos..any thoughts..to go on a 12 or 16 inch GSO RC.
Alex

[The_bluester]

They need a guide camera still but if it is the version I am thinking of, yes, they have an inbuilt pickoff prism in front of the filter wheel. Yes you need to buy filters.

I can't comment on putting it behind a bigger RC but Andy01 on here had one for some years behind a variety of scopes and it was a reliable workhorse of a thing, it just churned out data night after night.

[xelasnave]

Thanks Paul..I might get one as I do like the idea of not having to fit things together and it seems like a good chip...I wonder if buying direct is an option?
Alex

[Slawomir]

There is one for sale on classifieds.

Just a thought - Moravian is about to release a new C4-16000 camera with Gsense 4040 sensor (low read noise and 9 micron pixels). I have not used one made by Moravian but read positive feedback, and they have OAG and FW that comes with their cameras. 9 micron pixels should be a better match for a 12-16 inch RC, and the real estate is just fantastic.

[gregbradley]

Whether CCDs are better than CMOS would depend on the sensors.

The top large CMOS sensors seem to be at a slightly early stage but considerably superior. They will mature and minor issues ironed out over time.

The KAF8300 has been a super popular sensor and there are many wonderful images using them. The QSI model that uses this sensor appears to be the best camera maker out there for the 8300.

The wsg 8 is the model. Just needs filters but because the filters are a small size you often see these cameras using the higher rated filters like 3nm Astrodons 31mm.

That makes them pretty immune to light pollution. and great for narrowband imaging.

5.4 micron pixels suit many middle focal length scopes which is what most would be using anyway but also would work on shorter focal length scopes.

If I were getting another KAF8300 camera it would be the QSI683wsg8.
Having the filter wheel and off axis guider all on the one body would be very convenient and time saving.

Greg.

[Atmos]

One thing to really consider is that if you don’t use a reducer, even on a 12 you’re going to have a really small FOV. On a 12 you’re going to have a field about the size as the attached image. It’ll be even smaller on a 16”. You’d want a larger sensor and possibly larger pixels too as you’d be imaging around 0.32-0.45”/pixel.

[xelasnave]

Thanks to all I greatly appreciate the expert input.
I have been using that calculator Dylan O'Donnell made for Bintel which is so very handy for considering scopes, cameras and reducers..also Barlow's.
Thanks again.
Alex

[gregbradley]

I use this free calculator.
Its a great tool for comparing various camera and telescope combinations and you see the field of view and the sampling in arc secs/pixel.

You want to be in the range of 1 to 2 arc seconds per pixel for average seeing. Closer to 1.

Under 1 in good seeing.

My CDK17 is running at .42 arc seconds/pixel for one camera with 6 micron pixels and that works great when the seeing is very good. Otherwise it works
better with a camera that has 9 micron pixels.

The KAF8300 pixels are 5.4 microns so smaller again than the 6micron camera.

On a 12 inch RC that is going to need some decent skies to work well.

I have imaged with the KAF8300 on the CDK17 and then straight away with a 9 micron camera. It was average seeing, perhaps it was slightly poor seeing.
The 8300 was surprisingly worse in sharpness, very noticeable and not subtle.

I notice it now with a 2.4 micron camera at 1160mm focal length. Hard to focus and badly affected by poor seeing.

Greg.

[Paul Haese]

Alex,

I have owned several QSI's for quite a few years. One of them has never been re-gassed and was sold to friend of mine before I got the very same camera you are inquiring about. It has never missed a beat and he is very happy with it.

My 683WSG-8 did have a power board problem and had to be serviced. Unfortunately in Portugal and it came back still with a problem and had to go back again.

At a school I did a recent observatory installation, I installed a 683WSG-8 which has provided good service so far. No issues reported at all.

I had two 660WSG-8's and both had registration problems for the filter wheel. It might have been a batch where the problem existed. Others seem to have no issues reported in recent years.

I still own an 12"RC and would not put that together with a 5.4 um pixels (such as that on the 683 camera). The image scale is too small and the errors will be very obvious, especially guiding and mount errors.

My recommendation is to look for something with 9um pixel sizes.

[xelasnave]

Thank you Colin.
16 inch with .63 reducer is my latest change of thinking with a zwo 60 mega pixel binned 2x on eq8 oag guided if I can't find something to fit Paul's recommendation as to pixel size and add two gyro scopes to achieve perfect tracking.
Maybe a Myt Paramount to match zwo colour scheme because I am getting glasses to fix my colour blindness as well.
Alex

[Atmos]

Nice idea but it’s not really going to work I’m afraid. The .63 reducer won’t come close to fully correcting the ZWO full frame :(

[xelasnave]

True so Colin what should I buy? Then problem comes from being struck with the prospect I can finally be in one place and set up something permanent and undefined reason and a desire to have a 16 inch scope...the irony is I am very happy with the results I get with my 80mm and 115mm a d relatively cheap zwo camera..but I now have this roll off roof observatory and a question what to put in it I guess. I am doing so many things at the moment I just can't do the research I normally do and responding emotionally rather than addressing needs...today I fancy a 150 mm Espirit on an eq8 and whatever camera ...but again today so busy this will be the last I get to think about it until I get unrelated stuff out of the way..for others as usual.
Alex

[Slawomir]

It will be tricky to reduce an RC while maintaining a fully corrected field for a full frame sensor without spending a fair bit of dosh. I have heard APM is working on a a new reducer for GSO RC's. From current offerings, maybe a large Riccardi at the least, ideally something like Aluna RC reducer, but that would cost probably $5k landed.

With RCs, it might be best to stick to native FL with properly matched pixels. Alternatively, 150-160mm quality refractor combined with 4-6micron pixels should be much easier to run and would most likely still remain seeing limited (not aperture limited) for DSO imaging.

[gregbradley]

Reducers on RCs are likely to be problematic. I have a .66X reducer for my CDK17. It works great and corrects even the 16803 field of view but it has a tiny ideal metal back distance of 54mm. ZWO cameras and filter wheel and off axis guiders work on a 55mm backfocus requirement so that would be OK.
But my current setup meant I was too far off and I needed to use a guide scope.

It would work well sometimes and sometimes I would get some eggy stars. Not really bad but eggy stars are an image wrecker.

I have a large Riccardi reducer. I may try to rig it up to fit the CDK and see what happens.

I used to use a Tak FS102 F6 reducer on my 12 inch RC I had once.
It corrected the stars mostly but the corners were still not very good.

I later had a 4 inch Tak reducer, that may have worked but it would be experimental. I would predict it would be OK for an APSc sensor but a full frame one would have weak to bad corners.

Full frame sensors are quite demanding things.

Putting a reducer on an RC is probably not a good idea. Also you get the larger RC to get the extra aperture and the longer focal length. I don't know how much it speeds up exposures. Less than you may thing. Aperture is the thing that controls the light going in. Reducers just focus that light more tightly so that some of the light that misses the sensor is now hits the sensor. You get a wider field of view. I don't see that objects within that field of view get anymore light so exposure time will be the same.

Greg.

[Atmos]

You could get away with the ASI6200MM and do 3x3 bins which would leave you with a 6.7MP full frame camera. With a 12” you could get away with 2x2 bins which would leave you with a 15MP and a wider FOV.

I guess the question is whether or not there is something you believe a 16” will do that a 12” can’t?

[Paul Haese]

Alex, see my assessment above which you may have missed.

[gregbradley]

Depends on your seeing.

I can get sharper results using my ML16200 with 6 micron pixels with my CDK17 if the seeing is reasonable. That is compared to my Proline 16803 with 9 micron pixels.

If the seeing is weaker then the Proline is better.

ASI6200mm has 3.76 micron pixels which are smaller than almost any CCD.
2x2 binning would give you 15mp x 7.12 micron pixels which would be sufficient. Plus the file size would be a lot less, back down to a manageable 30.5mb each plus you gain a bit in sensitivity and signal to noise ratio. Plus I would doubt you would see the drop in resolution as 61mp is way overkill resolution for astro where 8.3mp often shows sharp images. This is all at 845 QE which no current common CCD can match and also read noise down as low as .7 electron. Modern CCDs run at about 6-12 read noise. Dark current is also much lower than CCDs.CMOS sensors though can generate a noise called "walking noise". I haven't seen it yet. I believe its easily avoidable and is a result of too low a gain on some models.

https://www.cloudynights.com/topic/613685-rain-noise-in-processing/

On paper the ASI6200 mono is in a new league. In practice I haven't seen too many images from it despite it being out for several months. The supply is always backlogged though and they are hard to get. Martin's images are with the QHY600m which is the same sensor but slightly different implementation. On checking on threads on Cloudy Nights though it seems the crowd prefers ASI over QHY due to a lot having been burnt in the past with poor drivers. I must admit, poor drivers would be a huge turn off for me having had those sorts of issues with FLI in the past. They eventually sorted their drivers although not 100% compared to other camera drivers. QHY offers different modes that can extract greater well depth but at the expense of higher read noise. I guess that would be handy if your were imaging Alnitak. You'd want maximum well depth so Alnitak would not be a giant bright ball of light in the image.

The ASI6200 would be good at 1x1 binning arbitrarily up to around 900mm focal length. Certainly excellent for widefield refractor imaging like an FSQ106 up to somewhere around a130mm APO.

Generally speaking small pixels are for widefield setups. Not a hard rule though as look at Lee's ASI183 2.4 micron pixel/250mm F4 Newt images. That's at 1000mm focal length or close and they are superb images.

That's where the 61mp is handy - for binning without any large loss of resolution. Martin Pugh posted some example images binned and unbinned about 4 months ago and they looked the same except the binned had an improved signal to noise ratio.

These CMOS sensors have higher MP count than your regular Astro CCDs and its one of their advantages.

Keep in mind 2x2 binning is only software binning not hardware binning which requires specific chip architecture which these Sony sensors don't have (mirrorless cameras don't offer binning at this stage).

For what its worth I would love to have one of these ASI6200 mono cams. My experience with the ASI183mm Pro has been positive.

I probably though am leaning towards the ASI2600mm Pro once its available. Same specs but APSc and US$1500 cheaper. If they had a mono version of the new ASI2400mc I would be interested as well as now you get 5.94 micron pixels and is like a KAF16200 except full frame.

The KAF 16200 is proving to be a sensor that works on any scope. The longer the focal length the more its sensitive to seeing but then so are long focal length scopes anyway so nothing new there.

Greg.

[xelasnave]

I only have a moment so please forgive my brief reply...
First I thank everyone for being so helpful, I really appreciate everything that is presenting. I am somewhat distracted with something else non astronomy and this scope thing just keeps going around and around...a con eliminates a line and pro sends me somewhere else where I find another con and I start over.

Paul I was trying to reply to all and so far have not been able to get past Colin, but in short yes I have read your post but only had time to deal with Colin's input and ran out of time.
I have read and reread everything here and against n thanks your posts are keeping me sane.
I will get back to this when I get my mind space back but when I am on a mission for someone I give all to working Ng on their situation. Must go.alex

[xelasnave]

Thanks Paul I really appreciate you sharing your experience and recommendation.
I have been able to address things a little better in the last two hours and now think I just need to back off and think everything thru...and learn much more like working things out myself rather than relying on the Bintel guide, read more about things... I have to think what do I want to do really and the more I think about it for a start I like refractors just because they don't really make demands that I can't manage...and really I can occupy myself for a while fixing the roll off..I need a ramp for example...today I was able to slip away and buy a second winch and some pulleys ..just fixing that will give me something to do and more time to think clearer.
Just the reading I have done in the last two hours has me more understanding of what is involved...I really appreciate your input on the camera ..thanks again.
Alex

[xelasnave]

Thank you Greg reading you experiences has been a great help.
The focal length of the 16 and even the 12 had me worried and I saw the fix as a reducer which seems not a good idea at all.
As I just now mentioned to Paul I am going to back off, learn more and try and work out my motivations and just what I want to do.
Thanks you have really helped me.
Alex

[xelasnave]

Thinking it thru Colin it is just plain appfever.
I am going to pull back finish what I have to do to the roll off and just learn more.
I really just need to learn more.
I need to motorised the roll off, build a ramp, place furniture start the pier and bring it up to a certain level.
Being able to devote uninterrupted time has me wanting to get it all happening.
In the last two hours I even wonder if the eq8 is the best idea...thanks for helping I appreciate your help and the others a great deal..
Alex

[Logieberra]

Suggest you take a close look at the iOptron CEM70... https://www.siderealtrading.com.au/product/ioptron-cem70-mount-head/

[xelasnave]

Thanks I have always liked their design... and please note my edit..I typed in appfever but approved was substituted.

Edit by way of addition.
That sounds a great mount for the money. I am surprised..lots of nice features..do you have one?
Alex

[The_bluester]

I don't think anyone has one in Aus yet. I am waiting for mine to arrive from hopefully the first batch into the country.

[Logieberra]

Same. You and I both!

[Logieberra]

I had an GSO 12” RC for a few years, sold it and “upgraded” to their 16”. I don’t wish to go into the full details here; but suffice to say I only had it for a few weeks before returning for a full refund. It was no upgrade.

[The_bluester]

Aperture fever is a nice thing to have if you can afford to feed it, but I have seen too many horror stories about collimating the RC design to ever go near one myself.

I see stories of woe from people on Facebook with RC scopes (Particularly big ones) where they have all the appropriate tools and do iteration after iteration of collimation, they reckon they have it right, but a star test still says otherwise.

[codemonkey]

To be fair, that sounds exactly like my story with my newt... collimation is hard... and yeah, I know, lots of people think it's easy and have no trouble at all, but for some of us it's not that easy. I only wish I could afford an 8" F5 triplet APO ;-)

[The_bluester]

There is that too, but I have seen people who can collimate a fast newt in a snap, struggle endlessly trying to make an RC behave itself despite having every required or suggested device and modification to the scopes.

Dont (Almost) all of us dream of a great 8" fast APO! I would love one myself.

[xelasnave]

Today's thoughts.
150 Espirit, eq6 8 or maybe the ioptron.

The Ioptron seems to good to be true.

Funny only recently I said mounts should come with built in guiding yet now that is available I wonder if it is a good idea given the benefit of minimising flex with an oag.

And back to thinking zwo for a camera, I just like their colour and service seems really great, although I still need to understand pixel size. But it would seem my two 1600 mono would be ok. until I figer what to get...

I had a crazy moment this morning whilst looking at a 16 inch dob and thinking to add decent structure to the tube and use it..it was f4.5. Doable I am not sure.

The 150 Espirit has the appeal of just working out of the box it would seem and maybe the focuser would be ok.

It's seems all zwo cameras have small pixel size. Mine seems small but it is ok to my untrained eye...plus I have the benefit of rather dark sky if that helps.

Maybe the 150 mm would work without an OAG.

Anyways got out this morning and pulled one winch out of the box and played around to work out where to put it and pulleys etc and think I have a good plan..I won't get bolts etc until Monday so I will think and look at it over the week end but it's looking good. Be good if I could rewire to use only one controller..that should work.

Figured to build an enclosed desk ..a desk with some sort of lid to protect from mice and water etc..but the roll off had heaps of moisture on the ceiling which is a worry. ..must check the size off the gift desks.

The ioptron is very appealing I presume it works with accom.. or does it?

The guide scope is only 120 mm ( I presume they meant FL and not app) ... it seems to have heaps of ports so will look into that. Plus a polar aligment scope...The design is so sensible I would have one in a flash except I like to follow the croud in new tech.

I suppose it's the unknown thing that worries me with it but really the new eq8 is an unknown also it seems.

Put my crystals in the small observatory and ran the little heater fan under the covers at 4 am until day break..I plan a routine of getting up early putting the genny on to make the batteries happy and run a room heater in the van...zero again in the van but although the heater hardly raised the temp the beautiful glow made you feel warm..I have a little one to bring up that has an artificial fire in it that would be nice here.so when that is a habit having a dehumidifier will work for me.

So current idea is to order a mount after the observatory is fit to take it..maybe just use my eight inch for a while before deciding on the next scope and camera.

Thanks again for all the help..after sorting the winch plan I feel that I am making progress at least...good thing the winches appear to have enough cable although I have some rigging left from boat days and more importantly the swagging tool which will be real handy I expect.Also I realised why I am in a rush..if I don't buy astronomy gear something else will come along and, well you all know how it goes, someone will want a car or a horse or a hot water service.
Alex

[Atmos]

An Esprit 150 matched with the ASI6200MM would be a killer setup. Higher resolution while still having a fairly wide field. It would be my choice and a major step above the ASI1600.

[The_bluester]

The only thing you would have to watch there Alex is I reckon for an Espirit 150 you would still want an OAG even with the CEM70G. I reckon guiding something that long FL with a 120mm FL guidescope built into the puck would be a challenge. Though at least a big frac would have the advantage of internally stable optics. Anything with possible mirror movement would be a real hassle I reckon.

The common wisdom seems to be with good rigidity, the inbuilt guider should be good to something like 600-700mm focal length. The real selling point for me was that I am setting up two rigs and while I am imaging at 480mm FL it allowed me to get USB3 connectivity and better electronics integration while kicking the cost of a second OAG and guide cam down the road a bit. So long as the inbuilt guider turns out to be a good thing.

[xelasnave]

Thanks Colin.
Your stamp of approval means everything to me. I feel much better about everything today particularly getting on top of the motorised roof problem..I got the first winch for only $150 which prompted me to buy it as that seemed cheap but when I went to get the second one they were not on special any more so cost me $200 but the really good news is Bunnings had some decent pulley wheels, only three, I needed four but the nice young man hunted up a fourth one that he thought had dropped down when the stock box was on the top shelf..so lucky there.
And the more I think about how good just the little 80mm performs and the 115 mm I expect the 150mm will do more than I expect.
Thanks again for your input I value it very highly.
Alex

[xelasnave]

I was thinking about it earlier. I have always tuned my mounts as good as they can be and my old eq6 I did an 11 minute run with the 80mm once ...It needs work again but my point is I think of guiding differently to most folk in so far as I expect corrections should be needed only say at 30 second intervals and the Ioptron seems to be very smooth and easy to achieve really good balance..the fact the polar is between two bearing says to me it should be rather good...anyways being always on the rush in the past and often having to settle for 30 second subs I see now reason why I can't manage.

And I found with the ZWO that you can get away with crazy high gain and short subs.. I was looking at some HA of something I did last night..30 seconds at 450 gain..not really flash but after StarTools the noise was not anywhere as bad as you would expect and as I combined that one with others with less noise it Sortta was quiet acceptable...maybe not to others but I make no pretence I just want the best I can do with whatever exposure and gain it takes...I have yet to incorporate dark and flats so I have many areas that I can improve upon...and in the future not being rushed can go for less gain, dark etc.

And like you I will be running two rigs that need guiding, three rigs all up and possibly a four if I bring the "cube" up here..over kill ..not at all.
But if the mount guide works it will be terrific.

EQ6 unguided with two DSLR cameras one with HA and a normal one that hopefully I can combine..still working on that one but two doing different things at least, the HEQ 5 with the 80 mm maybe a one shot colour, the 115 mm with the zwo 1600 and the new set up whatever it turns out to be....and possibly a secondhand mount and camera for the eight if I get the cube up here...

My reasoning is simple..to get good photos you need perfect conditions and they are rare so when it's perfect I will gather data like there is no tomorrow..also I find that late nights are getting to me so I want to shut down around midnight and be able to avoid sleeping all day...I have many things to do so I have to manage time smarter..and so it is perfectly logical and sensible to have four rigs running on a good night.

Soon everyone will be doing it...I have even been thinking three scopes one the new mount S, H and O but it's is not a simple as I would like data management wise.

The ioptron seems a sensible choice ..well it is if it suffers no issues...I will think more but there may be three of us in the Ioptron club.

Thanks for all your help I am most grateful.

Alex

[The_bluester]

Well, hopefully a couple of us will be able to give some feedback on the 70G in the not too distant future. I suppose as a torture test of the guider I could whack the SCT on there and see if it can deliver round stars.

[xelasnave]

Is there any indication of ETA.?
Alex

[The_bluester]

Not at the moment unfortunately. The ioptron site recently went from saying expected after July to expected after August.

But then the ZWO site still says expected around July for the ASI2600 and their feedback to me was "Speak to your local supplier" who had at that time heard nothing, then a couple of days later mine turned up. For all I know the CEM70 could be on the docks here, or still a collection of spare parts in a factory. The worst of it is having given my entire previous rig to my son for his birthday I am stuck until the mount arrives.

[xelasnave]

All the YouTube videos on Ioptron mounts in general seem positive. Sidereal have already replied to my email which impressed me being the weekend.
I think I will probably go for the "G" model and just a plain tripod but add a pier later...sounds like a bit of waiting all around...but I got one winch installed and working today so making progress.

[Logieberra]

You’re in good hands with Diego and Paul. Be sure to join their iOptron Users Group on Facebook.