wimvb

Will you do that modification? It would be nice to see the unguided tracking performance with this mod and pec applied. Anyhow, good to know in case a belt on my mount snaps.

Seems more reasonable to me (with little guiding experience).

10 degrees? That seems excessive.

2-3 hours should still be only one night. That would be a night well spent. Imo, that's a no-brainer (if the moon plays nice).

Great mosaic. And just 40 minutes per panel!

If you do put it to use, you should have a little plastic figurine right next to the open shutter, gazing up at the sky. Just for the fun of it.

Nice result, Neil. Did you also mix Ha with the red channel, or just as lum in the dslr data?

Yes, very likely. one intermediate solution would be to print a similar guide rail and glue it onto the existing parts. But that may be a poor fit.

Your neighbours won't see the difference. To them it will look like a robotic observatory. I was already wondering how you would engineer the shutter opening. (I just can't help trying to see solutions to possible problems. Sometimes it drives the people around me nuts.) So, here goes: Gina, would an interlocking system like this not be simpler? The image just shows the tapered interlocking parts of the shutter (upper part) and the dome (lower part). It closely resembles your initial solution, but may be easier to assemble and get to work. The hole could be used for a string that can open the shutter (would not be needed in the dome section)

That's the fun of engineering. Sometimes Usually it takes a larger garbage bag than anticipated. And a larger hammer. You fixed the curvature really well. Should run a lot smoother now. I can imagine the completed rig coming to life at night and starting photographing the sky, all by itself. What a sight that will be.

Gina, is the dome you showed here the real thing or a working model? If it is the real dome, I think that your locking mechanism with hooks /collar may not work with plastic, unless they are going to have a very loose fit. From your posted images (see below), it looks like the left movable section of your dome has a different curvature than the dome and outer section. Locking the sections as per your design image, can cause the sections to get stuck. I don't know how plastic is going to behave when outdoors in the heat and cold, wet and dry. But you may of course already have anticipated this. This is the image I'm referring to:

How are the moving sections kept in place? From your images it looks like they just sit on top of each other and can be lifted off. I assume there will be some mechanism to keep them in place. I think this dome will be impressive when finished and operating.

Nice to see the dome take shape. What is the diameter? It looks rather small.

That's the fun in this game that is AP. Whether you have a barndoor tracker or a MESU 200, getting the most out of your setup and having fun while doing so is what it's all about. IMO. But of course, at some time you'll outgrow the barndoor tracker, but probably not the MESU 200. That's when you have to throw (a serious amount of) money at this hobby.

Nice catch, at the very limit of what can be done with this setup, it seems. There really is a white dwarf in the center if this gem, and you seem to have caught it. When nights get darker again, you can try with different settings and maybe resolve it a bit clearer.

Well deserved. That's a very nice bubble & cluster.

Haven't read all the posts in this topic, but be carefull when comparing "brightness". This is a term left over from film photography, but can be misleading in digital photography. If you change the f-stop by changing the focal length, you also change the "resolution", as in how much of an extended object is covered by one pixel. A fair comparison of optical systems in digital photography has to take pixel size into account. Or try to normalise to a 1 um sized pixel (as Stan Moore tries to do in "Lessons from the Masters"). (I realise that this is throwing the discussion right into the jaws of the "F-ratio Myth", but I'm not going to discuss that. That poor horse has been beaten to death many times over already.) I'm leaning more to using resolution ("/pixel) multiplied by aperture diameter, as a measure for light gathering power of an imaging system. This may not be entirely correct, but at least it takes into account pixel size. In the discussion of images, here and in other online communities, the f-ratio isn't mentioned often, but aperture and total exposure time are. As you may be aware of, @gorann and I have been processing data from the Liverpool telescope recently. For this telescope (which operates at a slow f/10), total integration time is measured in minutes, rather than hours. But on the other hand the mirror is 2 m in diameter, and the pixel resolution is 0.3 "/pixel (binned) at 15 um pixel size. Apparantly, f-ratio is less important than aperture, and the f/10 system isn't that slow after all. (Just tossing my € 0.02 worth into the discussion)

Ouch! The belt tension may have been set too high. you can check it when you get a new belt. Julian's post is a good start for a replacement if the mount vendor can't help (might get two, just in case). Good luck

In short exposures, read noise will dominate. In long exposures, dark current (& noise) and sky glow/lp + noise will dominate. These two sources for noise behave differently. That's why you generally can't compare many short exposures with few long exposures, even if the total integration time is constant. The transition between read noise limited exposures and sky or dark current limited exposures is unique for each setup and conditions. The only way to find out what works best, is to experiment, like @Art Gecko did. Generally longer exposures are better, as is taking more exposures. But with modern low noise, cooled cmos cameras the balance has shifted to more and shorter exposures. Again: experimentation will give best settings for a rig/conditions combination. In this game, theory is never simple, nor flawless. And you can't take much for granted.

Great result. It certainly has a large dynamic range.

Hope the cake tasted as good as it looked, and that all went well. congratulations to you both.

+1. Excellent result on this group, Mikey.

Do you need to see Polaris? Polar alignment can be done without. For (initial) drift alignment, you don't need it in view either.

Just two questions, Gina. How good is the durability (especially uv resistance) of the plastic used? Some plastics become brittle when exposed to uv light for extended periods. The other question is about the middle section of the cover. From your image, it looks like this section can become stuck behind the fixed section? But you've probably already seen to this.