Adam J

The question is what do you want to use it for? Deep Sky wide field at a guess looking at your scopes. Assuming that it is this camera: https://www.altairastro.com/Altair-Hypercam-IMX183C-Colour-Astronomy-CMOS-Camera.html Then yes the IMX183c sensor itself is very well suited to the ZS61 and the Samyang 135mm lens due to its small pixels. I would be getting an IMX183 based camera if I had those scopes / lenses. HOWEVER, and its a big however, I would not myself purchase the Altair-Hypercam IMX183C myself because for me, for DSO imaging, it fails on two counts. 1) Its not cooled. Yes it is passively cooled but it has no set point cooling. That means that you will struggle with noise in the spring / summer and more importantly you will struggle to calibrate the amp glow out of your images using darks (a problem with this sensor specifically). 2) Its a OSC not a mono camera. If you live close to Portsmouth than you will experience light pollution and you are better off with a mono camera and although you can do Narrow band imaging using OSC (I have) it will work better with a mono. The two points above represent the pillars of dedicated camera imaging and if you don't have one you had better have the other. Personally I would rank it something like this: 1) Setpoint cooled mono camera 2) Setpoint cooled OSC camera 3) Passive cooled mono 4) Passive cooled OSC (The one you suggest) / DLSR. In essence what I am saying is that I would not consider that camera to be an upgrade from your DSLR assuming that your DSLR is modified then it may actually be better by virtue of having a larger sensor. If you got it I feel you would regret it. Its getting good reviews mainly because its great for Solar and imaging the moon, with the ability to do some DSO. What reviews have you seen? Save your money up and get a set point cooled version of the IMX183c like this: https://www.firstlightoptics.com/zwo-cameras/zwo-asi-183mc-pro-usb-3-cooled-colour-camera.html or even better a mono version like this: https://www.firstlightoptics.com/zwo-cameras/zwo-asi-183mm-pro-usb-3-cooled-mono-camera.html or the QHY version from modern astronomy: https://www.modernastronomy.com/shop/cameras/cooled-ccd/qhy-cooled-ccd-cameras/qhy183c/ If you really dont want to spend more than about 600 then I would even recommend the smaller mono ASI178mm-c over the Hypercam OSC or something second hand. Hope that helps, Adam

I seem to recall starting mine at the same time as you. Must me getting close to a year now. ?

I went with a pent roof with a hatch at the tall end to allow it to slide over the scope when opened without collecting it on the way.

Did you do anything to make sure that the draw tube can't be racked too far out of the tube and off the rear bearings?

At 1000mm focal length it will be hit an miss on the tracking accuracy to support a 2.4um sized pixel. Ill be interested to know what you go with in the end.

I would say its definitely unsuitable for that scope the pixels are to small. Down size to a 130PDS and bin a mono 183 2x2 and you will have a good combo...or if you really want OSC I think you would be better off with a ASI294mc pro or better still a ASI071mc pro for the larger field of view...but ditch the 200p in any case. What mount do you use?

Honestly get the mono version not the OSC! The tiny little pixels on the 183 are mainly suited to short focal lengths unless you bin 2x2 and you can only do that with the mono really, what scope are you thinking of using this with? Adam

I never understood why it would be harder to correct C-A in larger apertures does the whole thing not just scale as the scope gets larger at a fixed f-ratio? Is it something to do with the size of the star resolved at the image plain?

Got to say I never liked the idea of leaving those two sections intact, when I did it I decided to create a new stop by gluing a stop onto the tube.

I will own up to being one of the people who wanted to enter the narrow band imaging challenge with an OSC but could not. As such I completely understand what you are trying to do here and thank you for making the challenge as inclusive as possible. I am very content with this, just on the assumption that OSC will be able to enter narrow band imaging challenges in the future too.

A flip will not cause rotation, it does not work like that as far as I am aware.

You are a braver man than me taking this on over winter, i think I would have stopped and be waiting for warmer weather at this point. My 6x6 took me 4 months to finish and its tiny.

Yes I think that is almost universal (if you already have one then have a go) but if spending money with a goal of imaging with a 130PDS then dont go cheap and buy twice. The work gear ratio is the biggest reason i suggested a shorter focal length scope with the EQ3-2. I was at one point considering the EQ3-2 and the WOZS61 as a travel setup paired with the QHY183m when they get around to releasing it.

You will have a better time of it with the EQ5pro and and even easier time of it with a HEQ5 pro. So yes a EQ3-2 is possible as some have demonstrated, not sure I would go so far as Good and certainly not optimal. With the EQ3-2 I would be looking at a smaller scope than the 130PDS something like the the WOZS61.

Anyone know if a badder click lock will allow you to reach focus on a 130PDS? It moves the camera out slightly by the looks of it.....

Honestly I am now out of ideas, spikes are almost universally caused by protrusions into the light path. It could still be a twisted spider but you have checked that. So...strand of spider silk in the light path? Perhaps a primary mirror clip? Its an interesting one, i doubt flocking will help. Hope that you get it resolved.

This was a while back so it's difficult to remember. I'll measure it for you later.

Yes, the only thing that will be effected is its use with eye peices. Got to be honest though, I only use the 130PDS for imaging as do many others, as its not the best for visual so I would have a preference for one optimized for imaging. Beyond that, I consider it to be almost disposable at that price, just so long as I get a couple of years of use from it then I got my money worth, same with my DSLR. I cant sell it as a normal DSLR with its modifications but there are plenty of imagers who would take it from me.

Your correct, you will not have had to move the focus tube on a DSLR due to using a coma corrector, well maybe a 1 or 2mm as the badder MPCCMkIII does move it very very slightly. Its with a CCD that the position of the focus tube will move if not using the coma corrector (unless you space it anyway). Its because while the DSLR naturally places the sensor at 55mm from the coma corrector, you cant just screw a CCD into the coma correctors as it will be too close to the sensor and not correct correctly. NOTE: The position of the focus does not change, but that is not the same as the position of the focus tube changing. Different camera back focuses will result in different tube positions to place the sensor at focus. The use of the CC just forces you to modify the camera back focus to match the CC back focus requirement and so when using a CC all cameras result in the same focus tube position, just so long as the CC back focus is correct. See the diagram above.

Here is a diagram mate. Yellow = coma corrector Blue = Draw Tube Green = spacers / t-ring Pink = Camera body. In order: 1) A DSLR with a coma corrector, spacing from the back of the coma corrector to sensor = 55mm, this is made up of the DLSR mirror box 45mm and the T-ring 10mm. 2) A CCD using a coma corrector, spacing from the back of the coma corrector to sensor = 55mm, this is made up of a M48 to M42 spacer. 3) A CCD with no coma corrector, the spacer is not required so the tube is moved out to reach focus...although you could still use an extension to keep the tube in the same position. (Tube now not in light path). So the point is that the camera type has no effect what so ever, even in case 3 you can use an extension. You just need to mark the tube at focus to ensure that you don't take too much off it when cutting. Or as I said before, just move the primary mirror up the tube. This whole problem is why you only use a 35mm draw tube when you use a Moonlight with a 130PDS.

Its because when using the coma corrector you need to place it as a set spacing from the image plane (55mm). As such the camera moves backwards 55mm relative to the front edge of the focus tube (where the cc sits) and so to get focus you need to move the image plane (sensor) in by 55mm. In a DSLR the image plane is 55mm back from the coma corrector due to the depth of the DSLR mirror box so no spacers (apart from the t-ring) are required to gain the required spacing. If you use a CCD there is no mirro box and so you need to make up the spacing using spacers between the camera and the CC. Hence the focus tube position does not change when using a coma corrector irrespective of the camera being used. If you still don't understand I would be happy to provide a diagram.

The issue is more that it does not go across the entire tube diameter and so the angle changes as you move across the image plane.

That still leaves two sections of the focuser in the light path. Also you really don't need to remove that much only 1.5cm that looks like much more. Once you add spacers between the coma corrector and the CCD the focus tube will end up in exactly the same location when using a CCD as it does with a DSLR it has no choice but to. The main issue is when using it for observing...but you can still use an eyepiece extension.

It will not cause an issue, the back focus from the coma corrector remains exactly the same at 55mm so you need spacers between the coma corrector and the camera anyway. The only time it would be an issue is if you did not want to use a coma corrector and even then you could use an extension tube to allow you to reach focus. Removing only a square will not solve his issue he will just be left with additional surfaces at different angles in the light path and more diffraction lines. I know many people who have cut the focuser straight across and had no problem with using a CCD. You just need to add a stop to prevent it from being able to move out of the read bearings at maximum adjustment.

Actually, I think you got it. If I had a penny for every time this issue comes up with the 130pds when coupled with a DSLR...I would have something like 10p....