Adam J

My view in this is that CCD is dead, with the release of the ASI6200mm pro, ASI2600mm pro and the upcoming ASI533mm pro there is a CMOS for every budget that will either perform as well as older CCDs or more likely outperform older CCDs are a lower cost to own. I just cant imagine buying a CCD in 2022. Adam

Just bin the ASI6200MM Pro 2x2 in software, the read noise is so low that its going to make very little difference over having a dedicated 6um pixel. Adam

Its an expensive reducer on these scopes and only mild at 0.9x, not sure if they use ED glass in their other reducers though. The 62mm one is only ~70 cheaper than a ZS61 and corrector and we know that uses FPL-53, would be interesting to see a side by side comparison in the blue channel. The ZS61 also comes with such features as a handle and compression ring fitting included. Not to mention the SharpStar 61EDPH II at F4.5. Adam

Anything less than fpl-55 or fcd 100 and you are firmly better off getting a classic F7.5 ed-80 and fitting a better focuser. Adam.

It probably is sag, those ES focusers are not great. But I do believe that the ES scopes are colimatable by a skilled user. Its important not to confuse refractor colimation with centring the lens elements. A refractor can be user colimated through multiple methods, normally either a star test using an artificial star or via a Cheshire colimator and a illumination source when the user would adjust until the reflections from each lens element are concentric. I speak from personal experience. The lens is held in place by three sets of push pull screws and these are the colimation screws, the ones you should never touch are located around the perimeter of the lens cell and are used to centre the optical axis of each lens element. The are also the ones that typically cause pinched optics. Adam

Its being caused by the 1.25 inch adaptor. Its too small for the setup. Adam

Those are reflections between the microlens array and the filter. If its an unmounted filter then you could try flipping the filter over. Adam Adam

I agree its not a guide issue, if anything it looks like poor colimation to me. An out of focus star test showing 3-5 rings will confirm. If not the primary lens colimation then the draw tube needs to be checked with a laser to confirm that it is parallel to the optical axis of the scope. OP it is simply not possible to produce the distortion you have via a guiding problem. Adam

Unfortunately not, if set to pixels I believe Nina will use the main scope focal length to calculate arcseconds as Nina has no knowledge of guide scope focal length. So the value in brackets is likely not correct from my experience with Nina. Unless using OAG. Adam

If you are hell bent on it just make sure that you don't get any weird effects at zero gain in Darks first. But in answer to your question, there is no disadvantage to shooting 100 gain with the same exposure you propose. Adam

Thats 0.2 pixels total as you have it set to pixels and not arc-seconds and those are guide scope pixels not imaging scope pixels (unless off axis guider) and hence will be at a larger image scale (probably many times that of the imaging scope) so I am going to guess that this may well yet turn out to be guide errors. Set to arc-seconds next time and then compare the RMS / Peak values to your image scale. Also as above try really short exposures, 10s or so, on a star field and see how they look eliminating guide errors. Adam

Dynamic range is simply the trade off with gain / read noise and so I mention it. But I am struggling to see any technical factor that would make me choose 0 over 100. I would always take shorter exposures required to bury read noise if I could. I would actually push it up to 200 as 12 stops is still more than required. The only advantage of longer exposures is if you are worried about storage space. Adam

I really don't think that there is any justification for using gain 0 on this camera when you get nearly the same dynamic range at gain 100 and only 1.5e read noise. Adam

no not even slightly. Adam

I would do that with care, often (with exceptions) binning a CMOS at readout lowers the bit depth and actually does not have any advantage over software binning. You effectively place it in a video readout mode. Adam

You need to set the focus limits within the focus cube, focus controller utility first. Set Zero to just a little outside the min extension of the tube and then move to a position past the focus position for your rig and set the max. These limits are held within the motor controller inside the focus cube and so if nina attempts to infringe onto them nina and the cube may become de-synchronised. But if correctly set you should not be operating even close to the limits most of the time. Its all for safety. Adam

you can bin in software after debayering. Adam

Yes FLO where able to get hold of some tube rings for me for the FMA180 that I misplaced. Adam

A 50mm guidescope is serious over kill for a 230mm focal length imaging scope. Get a 30mm and it will solve some issues for you.

wipe as much off as you can first, if you flood it with water then you may end up as much flushing it between the lenses as you would flushing it off the front surface. Dont wipe into edge. Start at the edge and wipe outwards. edit: I see you already fixed it, glad to hear it. Adam

You may be better off with the 32 as the 40 has lower apparent FOV.

Try something with native ZWO camera support. Not sure if maxim does.

I like the original version better. The detail is impressive. Adam

Fully uninstal the drivers and start again. Are you running Windows 11? Or 10 and have you tried different capture software. Have you correctly installed the ascom platform?

Yes I think that the 7.5-14 volt is the input voltage am assuming that the internal electronics (motor driver board) are operating at a fixed voltage near the bottom end of that range after passing through a voltage regulator. Adam