tooth_dr

Here we have my comparison photos of the Baader versus Chroma. I was able to get a 36mm Chroma Oiii filter and I designed and 3d printed myself a holder to use this size of glass in my 2" filter wheel carousel. I originally printed in white, but ordered some black and reprinted it. I designed it to fit inside an spare UVIR filter holder. The original screw-on retaining ring was used to secure the filter. (Apologies for the slight sidetrack to the thread but 2" chromas were not feasible cost wise) I took these images below half an hour ago under poor conditions. 120s subs taken one after another with autofocus run before each image. 1) Baader Oiii 4nm 2) Chroma Oiii 3nm

It would need to be the entire focuser end plate by the looks of things as the m48 m63 adapter is fixed to the focuser end plate.

Hi Alan Hard to explain in words ! The large plate screws onto the focuser itself. It has an integrated M63 to M48 adapter which appears to be glued in situ. The inside of this plate has an m63 male thread and is designed to purposely hold the reducer so it can live inside the drawtube. The outside is M48 to attach normal camera stuff.

Thanks Alan. I would hope once this is correctly adjusted, I wont be removing or touching the camera again. I think there is some play in the threads, but I dont think enough to remove all the tilt. The only other issue that I have now thought about is the corrector is threaded via M63 male thread on the reverse of this M48 thread. How big an issue this is I dont know, but the corrector will be tilted relative to the image plane.

@symmetal I’ve attached a photo below. Last night I checked the 2600 for tilt. When rotated in the holder the laser pointer dot remaining stationary. I then swapped over the focuser base plates. On retesting the 2600, the laser dot drew a large circle when the camera was rotated. I swapped back the base plate to the original one and the laser dot once again remained stationary. This leads me to assume the base plate is the issue! The base plate has an M48 male thread in it, it looks glued in. I compared this to the other good base plate, and the other M48 part sits perfectly flat Here is a close up of what the tilted one looks like. Unless APM has set it up like this on purpose to match the scope it, but that seems unlikely. Where do I go from here to sort this out? Would Goräns suggestion above work?

I’m working late, but will post a photo later of it on the rig. I have as much of my imaging train removed in one piece, so right down to and including the base plate on the end of the focuser tube (circled blue). I keep the filter wheel and adapters attached. I loosened all the screws enough to allow movement of the plate.

Looking some advice, I noticed tilt on an image taken with my QHY268M and when checked it with the rig it was quite a bit out, with the reflection of the laser pen tracing a large 10-15mm diameter circle. I've tried adjusting it but it's still out. In fact it hasnt really improved and I had the faceplate 1mm off at one side. This sounds like a mechanical issue with a spacer or adapter?

The postman brought a small piece of glass today.

That is really something, thanks for sharing something completely new.

See here: How to adjust tilt during the day

Nicely written up Andrew. Your rig looks very similar to Daniel Sundström's who shared his video on here, which was then subsequently developed into a simpler rig, that a fair few of us (icluding myself) went out and copied! Adjust your CCD or CMOS astronomy camera tilt during the day with a laser pen

Is there much difference in these two? I’m Bortle 4 but most of my imaging is over my local town (large enough with about 25000 people) which is in the distance to the south

See I actually thought of this - I knew adding the NBZ would add 1/3 filter thickness which is why I purposely calculated my back focus to this and then added a UVIR filter for when I took the NBZ out to compensate. It never occurred to me that filters came in different thicknesses, I took it for granted that they all were 2mm. With my dual rig accurately aligned (including rotation), and tilting accounted for using ollies chip tilt rig idea, the idea removing the main camera is 🤯 If a 2.5mm clear glass filter will solve this and let me continue to use the OAG then i would like to do that but does it work like that?

Sure looks like it 😅 but that is the problem. When the OAG is in focus with the focuser at position X with filter A all is good. But then I have to refocus to position Y with filter B because it's thicker/thinner, and it bends the light more/less. When the focuser is at position Y then the OAG is not in focus. Looks like I need two filters with the same thickness so that the focuser is always at position X or very close to it. Thats how I'm interpreting it.

I want to avoid refocusing my guidecam. I’ll switch to a finderguider if it can’t be done. Thank you for your first hand insight! I thought that 2mm might be close enough. If I can get a 2.5mm filter I will but it’s a bit if a rip off at £120

I’m not having an issue getting focus, rather a shift in OAG focus when filters are changed, that means I have to manually adjust the OAG stalk. My back focus is 75.6mm with a Riccardi 0.75x reducer, not 55mm, so I have a bit of room to spare.

It’s F4.65 Vlad, pretty fast. I would like to truthfully avoid any additional focusing but that is a nice solution. Here is my assembly

The OAG is before the filter. In my head this was the right way. But when I change filters it puts the guidecam out of focus when I refocus the main camera. This makes sense when I think about it now.

Cheers Michael. Refocusing the guidecam is a non-starter as it’s done with both thumb screw and allen key bolt, the latter of which is very awkward to access. I’m more concerned about the NB filter, can’t imagine being that many stars. I’ll try to get a 2.5mm but IDAS don’t seem to be making one.

I appreciate you taking time to reply with images and I very much agree it's disappointing given all the hype.

I'm sure you know that even the APS-C IMX571 wont work with 1.25" filters either.

It's total integration time thats important as @vlaiv is saying. If you can get a good image from the new OSC in one night, then you'll get a better version of that same image in the same time frame with a mono. That is provided you have a means of changing the filters and refocusing the scope.

This is just a quick stack saved on my PC from some of the data the other night, 50 minutes of data with mono IMX571 and 3.5nm Ha filter, and same with OSC IMX571 and NBZ filter (Ha extracted using APP algorithm for dual band filter), both processed in APP, and saved as jpegs. I think with the moon etc, this isnt a fair comparison, but I hope to have plenty of data moving forward to add to the thread if needed.

Or I could just post my data that I took with my dual rig mono and OSC ☺️

What about 8 hours of OSC dual band data compared to 4 hours Ha + 4 hours Oiii from a mono?