On Mon, Apr 5, 2021 at 12:12 AM, Davidspain wrote:

El telescopio no tiene marca, es fabricado por mi 300mm f / 4, con anillas parallax y milano losmandy 44cm. Mi otro telescopio

Hello David

I assume you want to image and not just for visual?

I think the G11 is a good choice to support this telescope. 24kg is within weight limit, i assume camera and other equipment will not add much weight to this? f/4 means your focal length is not as long, so guiding should be okay.?


The G11T can also support your telescope, but i think it may be too much for you.?

Brian

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开云体育

Hi Michael,
thanks for the details of the reflective insulation. I believe it's readily available at Home Depot here but appreciate the offer. looks like I may go that route as well with my newt. Only question is, will this extend the required cool-down time of the primary mirror?

Tom

On Tue, Apr 6, 2021 at 12:00 AM, Michael Herman wrote:

Very nice work.

You have nicely demonstrated a faster and more consistent way to polish down the R4 bearing OD.??

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As you say, you must always be very careful around any power tools.? We are in a hobby for fun, not for danger.? So care if the hands and eye protection, and a face mask to avoid inhaling dust are important precautions.?

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That said, I have used my bargain priced Wen brand drill press to polish ODs down (on brass rods) before, so this is an accessible way of polishing small round items at rather low cost.? The drill press has no explicit cutting tool in it...just a round bearing.??

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The only thing doing the cutting is an emery cloth or fine sandpaper.? (I like the 3M "wet or dry" paper because the grit is well embedded in a kind of string waterproof adhesive.? You can wet the paper to keep polishing dust down.? ). The sandpaper can get hot, but it generally won't cut you.??

?

The notion about extra benefits of allowing the bearing (at least the far bearing away from the gearbox) to self adjust it's angle in the worm block...these are new ideas.? We don't really yet know a "spec" on the best amount of OD slack to use.? Ideally you don't need any slack at all if all the parts are perfectly made.? Most people never see the 76 sec oscillation so never need this extra workmanship.??

?

A theory for the riddle:

? ? "why is a single Belleville washer under the (OD loose) far end bearing sufficient?? Why don't you need that spring under both bearings? "

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An idea:?

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Many people preload their RA axis with an intentional East bias. Say a weight on a cord, wrapped so the weight hangs to the East side of the RA axis.? We have discovered that the East bias eliminates a vibration ("chatter") that occurs if you bias to the West instead.??

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When you preload the RA axis (ring gear) with an East bias, this forces the worm to move West.? That presses the worm against the West "far" end RA worm bearing center, and leaves the near (near the gearbox) bearing center looser.? So the West far worm bearing becomes the more critical surface for the RA drive: the worm is mostly rotating on that ball bearing race surface, not in the bearing closest to the gearbox.? ?That's why eliminating rumble of that far bearing becomes more critical for low noise sidereal tracking.??

?

This idea might explain why we see a reduction or elimination of the 76 sec oscillation when we reduce the OD (allowing tilt) and put a Belleville spring behind just the far worm bearing... the spring allows the bearing when tilted to still ride on a "self-leveling" seat.? ?

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Otherwise, reduction of the 76 sec oscillation should only be effective some of the time...but it seems to be working all the time.? The East side bias effect could explain this riddle.?

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By this reasoning, using a West side bias might create a 76 sec oscillation even with a Belleville spring under the far West bearing? ...there's another experiment to try!? ?

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All the best,

Michael

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On Mon, Apr 5, 2021, 10:01 PM John Kmetz <jjkmetz54@...> wrote:

Alan/Michael/all:

Just tried the bearing spinning rig today with success. I placed the assembly in a drill press at 100 RPM and started trying small metal files and types of sandpaper to hone down the bearing. Surprisingly the outer race is fairly hard steel and doesn't shed diameter easily. Finally I used the corner of a sharpening stone, like that used for scissors or straight razors, and that was the trick. Subsequently I polished with 200 then 600 mesh sandpapers. It looks like reducing OD about 0.002" is the point where the bearing will begin to slide freely inside the block (see pics). The outside race also seemed to be virtually round and smooth after this process. Before pulling apart the rig, I sprayed away all the sanding dust with some WD-40 and then some compressed air. Upon finger turning the finished bearing I did not sense any hang up or grittiness inside.

Perhaps this is a new way for reducing the bearing OD to allow the Belville washer to do its thing. I found this a bit easier than turning down by hand. Perhaps a bit more OD reduction might be needed for those who wish some off axis tilt, but too much might start the bearing turning inside the block. But I think polishing down to 0.623" is the place to start. But just a note a caution for those who are not that familiar with moving machinery: the spinning drill assembly could easily cut the skin, or send particles into the unprotected eye. Use precautions.

Hope this info is of use.

John

Michael,

By loading the outer bearing's outer shell you are loading all three pieces, putter bearing, worm and inner bearing. So the side of the mount should not make any difference and the 76 second error will not be present on either side of the pier if done correctly and no other issues are present in the mount or drivetrain.?
?
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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?

Alan/Michael/all:

Just tried the bearing spinning rig today with success. I placed the assembly in a drill press at 100 RPM and started trying small metal files and types of sandpaper to hone down the bearing. Surprisingly the outer race is fairly hard steel and doesn't shed diameter easily. Finally I used the corner of a sharpening stone, like that used for scissors or straight razors, and that was the trick. Subsequently I polished with 200 then 600 mesh sandpapers. It looks like reducing OD about 0.002" is the point where the bearing will begin to slide freely inside the block (see pics). The outside race also seemed to be virtually round and smooth after this process. Before pulling apart the rig, I sprayed away all the sanding dust with some WD-40 and then some compressed air. Upon finger turning the finished bearing I did not sense any hang up or grittiness inside.

Perhaps this is a new way for reducing the bearing OD to allow the Belville washer to do its thing. I found this a bit easier than turning down by hand. Perhaps a bit more OD reduction might be needed for those who wish some off axis tilt, but too much might start the bearing turning inside the block. But I think polishing down to 0.623" is the place to start. But just a note a caution for those who are not that familiar with moving machinery: the spinning drill assembly could easily cut the skin, or send particles into the unprotected eye. Use precautions.

Hope this info is of use.

John

I don't see where this design allows for tilt self-alignment of the worm blocks

Good point Alan.? I need to pull the near worm block down in order to prevent tilt.? One or two Belleville washers would work fine.

I tried this last night and noticed that the flex coupler moves the near block all over the place.? By pulling the block down so it remains flat, this effect will be greatly reduced.? For now I stuck a plastic washer in between and that already helps a great deal.

My money's on the Spring Loaded Worm assembly.

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Jim W
Phoenix, AZ. USA

To me it sounds like some spacers or wavy washers are missing.

My C8 edge has the same clothes:-) Got to love that Reflectix!:-). ? Seems to work pretty well so far. ?The big test will be this summer when humidity is in the 80% region, which is also when it is usually best to shoot planets around here:-)

JMD

Wanted to share a fantastic thank you to the staff of Losmandy for expediting my tripod extension for arrival this past Saturday.? I had a crew here working on my observatory on Saturday and when I talked to Losmandy earlier last week, we realized the extension for the scope I ordered would not make it to my site on Saturday (they were shipping it the day I called), Losmandy changed the shipping priority on their own so the extension would arrive on Saturday, which it did.

We modified the observatory and the mount setup and had everything up and running for dusk on Sat Night and spent the next few hours imaging!!!!? I ordered the extension because my scope and camera system was able to strike the pier plate (even with safety limits in place) and I was too worried about that.? The 12" extension now allows enough clearance for the scope/cameras to point straight up with no issues.

Thanks again Losmandy!!!!!!!!!!!!!!!!!!!!!!!

Russ

Curious:? I noticed the firmware date on my mount (via the HC) states a date from 2017 (forgive, I don't remember the exact date).? The Losmandy Website shows a firmware version from 2018.? Yesterday, I updated the firmware using the Network Interface to my mount which does everything automatically and in the end, stated the firmware was updated and to reboot the mount.

However; I noticed the firmware date did not change after the firmware was uploaded.??

Any comments regarding this?

Russ

Realized something new (for me anyway).? I've been using the virtual HC on my PC, the one you download from the ASCOM site.? This has been working fine for me but is where I noticed the LAT/LONG/TIME setting could not be changed once connected to the mount.

Last night (for some reason I had completely forgotten all about the feature), I used the HC controller via the Losmandy network interface.? Using that feature, I did not run in any issues with the mount or scope interface.

Russ

Awesome work! Can't wait to see what it produces when the sky's clear!?

Michael,
I assume that wrapping on the OTA is for insulation to minimize expansion and dewing??

Tom

Do you have a part number for the Bellville washers? ?

Thanks,

JMD