wimvb

Please share the fits image(s).

Check for backlash/binding first. After you have adjusted that and it is still stiff, loosen the lock nut in the DEC housing. Just take the cap that covers the polar scope hole off and loosen the nut by just a tiny bit. Don't loosen it too much. You want smooth movement without being able to wiggle it sideways.

Yes, by all means, keep us posted. (See my comment on my own thread). @dazzystar: if you just want the RA axis to run smoother, then loosen the RA lock nut by a fraction of a turn. Remove the polar scope and RA ring. Then loosen the three grub screws that lock the RA nut in position. Loosen the lock nut just a little and retighten the grub screws. Put the RA ring and polar scope back on. This is a very easy modification. You just have to make sure you loosen the grub screws (hidden in the side of the lock nut), and find a way to loosen the lock nut (it may take quite som force).

No video, didn't even take pcitures. I did most of the modification yesterday. It went mostly well, but I also learned that some of the issues that this mount has are not related to the red shims or the lack of smoothness because of them. If you closely examine the video, you'll notice that Petter Åström (who made the video) did a lot of small adjustments to both decrease backlash and to get DEC and RA to run smooth. For example, the central rod with the two bolts that hold the DEC axis in place, needs fine adjustment (besides adding any bearings). You can't just tighten the bolts. I found this to be the case for the DEC bolts (one on either side) and for the RA lock nut. Furthermore, the bearings take up space and push some other parts further out. Petter added washers to the DEC worm block, but this creates gaps where moisture and dirt can get into the mount. After I put in the bearings, there was a definite improvement in how some parts moved, but I also found several places that needed careful adjustment. Unfortunately, I didn't have time to finish the work, and will have to continue next weekend. As final notes (so far), some of the bearings that Petter used where too large, and anyone planning to do the modification, should spend some time looking for bearings that fit better. The RA worm wheel (part where the clutch acts on) has a diameter of 34 mm, so a 34 - 35 mm (inner diameter) bearing is ok. The RA shaft has a diameter of 25.5 mm (1" ?), and should have a bearing with this or 26 mm inner diameter. The DEC shaft has a 20 mm diameter and M10 threads on either side. For this you would need bearings with inner diameter 10 mm and outer diameter 20 mm. The DEC worm wheel has a diameter of 32 mm where the clutch acts, and a 20 mm bore for the DEC shaft. This needs a bearing with 20mm inner diameter and 32 mm outer diameter. A bearing under the RA lock nut (the one with 3 grub screws to lock it in place), will push the lock nut out to the point where it interferes with the Right Ascension ring. If you keep this, the scale on the polar scope will push against it. Some of the bearings will press against the aluminium housing, so they will need steel rings. Petter used 1 mm rings, but they should ideally be thinner. I thought that the worm end bearings in my EQ3 where quite smooth, but I replaced them anyway. The worm gear runs smoother now. This was the easiest fix. The plastic cover of at least the RA motor is a poor design, and there is a risk that the RA transmission gear scapes against the plastic. I still need to address that. All in all, if you, like me, have an EQ3 lying around and like tinkering, then by all means, enjoy yourself. But if you have little or no experience with this kind of work, then stay away from it. Adjust backlash, and enjoy the mount as it is.

By a mile. I have an AZ-EQ6, and a friend has an EQ6-R. They both sit on their pier less than 2 m apart. The AZ-EQ6 is some 3-4 years older and it guides with maybe 0.1" rms more. I find the altitude adjustment of the EQ6-R hopeless. Otoh, the altitude adjustment of the AZ-EQ6 is very close to the scope tube (190MN). I chose the AZ-EQ6 at the time because of its altitude adjustment. At 60 degrees north, I didn't want to exchange bent bolts every other month. And btw, I've never used my mount in Alt-AZ mode, and I have the encoders deactivated.

I agree, if you can't keep the proper reduction ratio, you're in for trouble. But as I wrote, the motor gear has 12 cogs/teeth, and the next gear wheel has 66 cogs/teeth. The reduction ratio 11:2. This can be maintained with a 55 teeth pulley on the worm shaft, and a 10 teeth pulley on the motor shaft. The problems that remain are how to keep the belt tensioned, and how to remove the small gear that is pressed onto the motor shaft. My guess is that this mod costs more (labour) than what it's worth (in terms of improved tracking). For the time being I'll stick with replacing the washers inside the RA and DEC assemblies with bearings. But a belt drive EQ3-PRO would be a cool thing to have.

Just for future reference: the worm shaft has a 6 mm diameter, while the motor shaft is 5 mm. The tiny motor gear is pressed on the motor shaft. Where the gear sits, the shaft is narrower (2 - 3 mm).

Thought about that too. The mount has a gear reduction ratio of 66:12, or 11:2, ie 12 cogs on the motor side and 66 cogs on the worm side of the gear box (there's also a 35:35 translational gear). I found some 55 tooth pulleys online, so could do a 55:10 reduction. Any belt would need tensioning, which would be another challenge.

@tomato star reduction through morphological transformation replaces the affected pixels by a calculated value; the same calculated value for all the pixels in the "sample" or morphological cell size. This creates a smooth halo around reduced stars. I always add noise to these halos so they look more natural. I use PI noise generation tools with the star reduction mask still in place. Test on a preview to determine the best noise level.

I have never really been satisfied how the EQ3 mount is designed. For example, the mount lacks proper bearings that support the RA and DEC worm gears. Instead it relies on a few plastic and paper washers for smooth tracking. Last week I saw a youtube clip from a Swedish amateur astronomer who had removed these washers and replaced them with 2 mm needle bearings and cover rings. Today I received the bearings that I will need to make this upgrade, and since the forecast for next weekend doesn't look that good anyway, I might as well scratch that tinker itch and disassemble my EQ3-Pro.

There were reports a while ago that the point where the camera switches from low conversion gain to high conversion gain could show some instability, and that a gain value close to this point better be avoided. Those reports were never really confirmed. But more importantly, at 0 gain the dynamic range (full well / read noise) is largest, so you can have weak signal and still avoid blown out stars. At low gain, the camera works more like a classical ccd camera. Instead of doing a lot of short exposures to increase dynamic range in the final image, you can do fewer but longer exposures. Mind you, cmos still works better with many and shorter exposures than CCD. I find that low gain works for me.

You used an exposure time of 300 s at gain 120. For narrowband that would be ok, but for LRGB I think you won't need this much. I image with 4 minutes subs at gain 0 and offset 8 (RGB) or 120 - 180 s for L. Narrowband: gain 200 offset 30, 4 minutes exposures. Make sure that your offset is such that a single sub has a minimum value different from 0, but not much higher. Decrease offset if the minimum value is high, increase if minimum = 0.

I think that that's the idea. They're probably not going to compete against SpaceX, but aim at a high volume market for small satellites

I think this is a viable option to get small payloads (not humans) into lower earth orbit. Spin launch a small rocket to a sub orbital trajectory and give it a boost for final orbit insertion. Much less fuel needed. Mind you, this won’t get humans to Mars.

I guess that’s why mount tuning companies rely on feedback from clients rather then verifying in the field before shipping the mount back.

You think so? The chrome details did it for me. A nice change from SkyWatcher white. 😉

ZWO, Sharpstar, Pegasus Astro, Rainbow Astro, Artesky, and possibly Rowan Astronomy. Why suddenly the hype? Is everyone going portable all of a sudden?

With a longer fl scope and the same camera (pixel size) the angle/pixel will be smaller, so the arc secs RMS will be smaller too. But only by 10% in this case.

I haven't exami ed the guide log, but in the screen shot it loons like backlash in dec. Run the guiding assistant for 10 minutes and determine how much backlash you have. If it's not too bad, PHD can compensate for it.

There is no 4/3 alternative that I know of. You'd have to invest in the next size up, the 2600MM which is APS-C. The ZWO model is expensive, so to keep the price down, you have to get the RisingCam version or something similar. You'd still spend a fair bit more than what the 294 costs.

The ASI294 does have amp glow but it calibrates out fine. Otoh, if you have the option to get a cmos without amp glow, go for it. @deanchapman2705: Having the possibility to switch bin states may seem appealing, but there are some major caveats to this. If you look on the ZWO web site, you'll discover that the ASI294 specs for the bin 1 state are not even close to the standard bin 2 state. So, you'll probably end up having to capture more subs to get good masters. And you'll need to do that with 4 times larger image files. So, you'll need the hard drive space and RAM to handle those larger files. I'm also not sure that even with the WO61 you'll see that much more detail in bin 1 than in bin 2.

Two unexpected clear nights that in hindsight weren't so clear after all. I started this image as an experiment in guiding, but ended up collecting data for almost two nights. Unfortunately the sky wasn't as clear as it looked, and I had to discard about 60 % of the subs. Still, this is about 2 hours worth of RGB data with short exposures in order to try to keep as much colours in the stars as possible. Captured with my SkyWatcher 190MN and ZWO ASI294MM, 64 x 2 minutes subs Processed in PixInsight. And yes, there are distant galaxies in this image, but they're tiny.

It would be interesting to see a galaxy like M33 edge on. Andromeda probably looks like ngc 891 when viewed edge on. https://www.astrobin.com/rv9f2p/

Better. I think that we see more detail in the core of M 33 as compared to M 31, simply because M 33 is a different type of galaxy. M 31 and the Milky Way have a massive black hole at the centre, with a bulge of (old) stars. M 33 lacks both a central black hole and a bulge, it's a pure disc galaxy. It also has a much higher rate of star formation than M 31.