Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
Well...if you really did buy 125:1 not 25:1, ?That's a new experiment!
Can you share with us the part number and place you ordered from???
Thanks, Michael
On Mon, Jun 14, 2021, 12:58 PM Michael Herman via <mherman346= [email protected]> wrote: Surely you mean 25:1, not 125:1
The stock gearbox is 25:1?
The McLennan 25:1 gearbox rotates the opposite direction, do all you need to do is change the sign of the ring gear teeth (for G11 change 360 to -360).? You leave the gearbox setting at 25.
Best, Michael
I've opted to change out the gear boxes with McLennan 125:1 ratio.? I have one unit arriving tomorrow and will be ordering a second. I was able to successfully change the controller settings for the gear box values to 125 and set the steps per worm revolution to 32000. I guess the speed settings need to be divided by 5, except for Guiding speed which I've kept at 0.8. Everything ran OK. So 0.112 arc sec per step. Less expensive than changing the encoders.
|
Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
Surely you mean 25:1, not 125:1
The stock gearbox is 25:1?
The McLennan 25:1 gearbox rotates the opposite direction, do all you need to do is change the sign of the ring gear teeth (for G11 change 360 to -360).? You leave the gearbox setting at 25.
Best, Michael
I've opted to change out the gear boxes with McLennan 125:1 ratio.? I have one unit arriving tomorrow and will be ordering a second. I was able to successfully change the controller settings for the gear box values to 125 and set the steps per worm revolution to 32000. I guess the speed settings need to be divided by 5, except for Guiding speed which I've kept at 0.8. Everything ran OK. So 0.112 arc sec per step. Less expensive than changing the encoders.
|
Starlight Xpress has a 'mainstream' AO unit
Adaptive Optics is still complicated because it's essentially guiding PLUS a bunch of other stuff. and you have to worry about backfocus?distance, parfocal for the guide camera, etc.
It would be great if there was an image stabilization type thing built into the camera like we see in mirrorless with IBIS
On Mon, Jun 14, 2021 at 12:24 PM David Malanick < malanick@...> wrote: I always wonder about AO devices.? I see them for the old CCD cameras for sale at around $1000.? I thought by now someone would have figured a way to integrate them for any modern camera setup. Writing an ascom driver or something.? And why hasn't some manufacture come up with a mainstream AO device??
-- Brian?
Brian Valente portfolio
|
Re: next podcast topic: dovetail plates
Brian - interested in comments on Vesa support and any other devices you may have already included in your design plans -
Thanks,
Ken
|
Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
I've opted to change out the gear boxes with McLennan 125:1 ratio. ?I have one unit arriving tomorrow and will be ordering a second. I was able to successfully change the controller settings for the gear box values to 125 and set the steps per worm revolution to 32000. I guess the speed settings need to be divided by 5, except for Guiding speed which I've kept at 0.8. Everything ran OK. So 0.112 arc sec per step. Less expensive than changing the encoders.
|
I always wonder about AO devices.? I see them for the old CCD cameras for sale at around $1000.? I thought by now someone would have figured a way to integrate them for any modern camera setup. Writing an ascom driver or something.? And why hasn't some manufacture come up with a mainstream AO device??
|
Re: ASCOM Device Hub or not
I am using the Ethernet configured Gemini.NET ASCOM driver/server for SC and PHD2. The only issue I get is that the Gemini web interface sometimes hangs until I shutdown the other apps (maybe not Gemini.NET related).
Paul - some time back there was a suggested DCOM Authentication Level change for the Gemini and SkyX DCOM modules for users with problems (64 and 32 DCOMCNFG if needed). I currently have None as my authentication level but may be worth a comment. I am using 64bit .NET 3.5 but 5.0 is now out - any comment on recommended versions going forward also? Sorry to raise a deviation to the original question but may be beneficial longer term.
|
Re: next podcast topic: dovetail plates
oh nice!
that's pretty badass?
We will discuss the hole pattern but here's a spoiler alert for you:
it's a 7" pattern that repeats based on the dovetail plate length
here's that 7" hole pattern:
It will be cool to see a diagram of what those hole patterns are for on the dovetail plates.
I was pleasantly surprised when the mounting holes on one of my unused Losmandy saddle clamps fit perfectly on the bridge on my Takahashi scope rings.? I attached a metal pull handle to a DUP7 to make lifting my TOA130 much easier.? I can remove the handle and use the saddle clamp to hold accessories on the scope.? Very handy.
-- Brian?
Brian Valente portfolio
|
Re: next podcast topic: dovetail plates
It will be cool to see a diagram of what those hole patterns are for on the dovetail plates.
I was pleasantly surprised when the mounting holes on one of my unused Losmandy saddle clamps fit perfectly on the bridge on my Takahashi scope rings.? I attached a metal pull handle to a DUP7 to make lifting my TOA130 much easier.? I can remove the handle and use the saddle clamp to hold accessories on the scope.? Very handy.
|
At some point if I decide to up my game, I may try an AO device. That seems to be somewhat of a silver bullet, and maybe cheaper than getting a higher end mount. For now I'm have to say that I'm really happy with my GM811G. I've had it for a couple of years, and it's taken me a while to learn how to adjust it, but I tend to get very reliable results over long periods without doing any adjustments. I just take it outside, setup and start imaging. It seems that the worm might need adjusting once in spring and once in fall. I tend to get results that range from 1.1 to 0.4 RMS, and that suits me just fine. When multi-star came out I saw results below 0.4 RMS for the first time. I was worried that it was just a fluke. I'm guessing that it only happens when seeing is good, but I've seen it fairly regularly over the last few months. The last few nights of imaging I was getting guiding around 0.5 RMS with it dipping into the low 0.4's. I only get obsessed with tweaking things for performance when I'm imaging small things like the cat's eye which I was doing last night. -- and I didn't have to tweak a single thing, it just worked!?
An AO device may be what I do for a future upgrade if I want to get better images with the small objects. I'm also wondering how sensitive cameras will get over time. Maybe subs will get shorter and shorter making all this work tweaking the mechanics obsolete?
Jamie
?
|
Re: ASCOM Device Hub or not
Hi Edward,
That's correct. Gemini.NET implements a local server ASCOM pattern and runs in its own process space. It can be shared by multiple client apps through COM, regardless of whether they are 64- or 32-bit processes.?
Indeed, POTH is an extremely useful piece of software, just not for the reasons that were mentioned in this thread :)
Regards,
? ? ?-Paul
toggle quoted message
Show quoted text
On Mon, Jun 14, 2021 at 12:37 PM, Edward Plumer wrote:
Paul, Thanks. Since I am not much concerned about TheSkyX, I will stick to my original question about Gemini driver.? To clarify, are you saying that Gemini always runs out of process as a DCOM service regardless of what client invokes it??
By the way, though this does not invalidate anything you said, I might point out that another key functionality of POTH/ADH is that it provides middleman functionality. Of interest to me has been slaving dome rotation to the mount ( yes, my use of POTH has been a tangle of reasons). In using NINA, I am now able to let it do the dome slaving. This thread has clarified that, with Gemini, I no longer need POTH for connection sharing either ... awesome.
--
Edward
|
Re: next podcast topic: dovetail plates
How about easy solutions for co-aligning side-by-side setups. I went through a bunch of kludges for the Venus Transit and eclipse to get two OTA to both center the sun.
--
Edward
|
next podcast topic: dovetail plates
Hi folks ? The main topic for our next podcast will be Losmandy dovetails. ? I wanted to see what Dovetail-related questions anyone might have that we can try to answer ? ? It will be more in depth and discuss things like history, hole patterns, radius blocks, D vs. V style, etc. ? ? We will also be introducing a new ¡°configurable dovetail¡± option in our catalog, so you can customize your dovetail when you order it ? ? ? Thanks ? Brian ? Brian Valente Losmandy Astronomical ? Losmandy.com Tutorials and vids at ?
|
Re: ASCOM Device Hub or not
Edward - I just want to clarify (and I think you know this) that the Gemini ASCOM driver is a hub itself.
there are some ascom drivers that aren't a hub and require a third party hub middleware kind of approach. Optec has an interesting one as well
On Mon, Jun 14, 2021 at 9:37 AM Edward Plumer < eplumer@...> wrote: Paul, Thanks. Since I am not much concerned about TheSkyX, I will stick to my original question about Gemini driver.? To clarify, are you saying that Gemini always runs out of process as a DCOM service regardless of what client invokes it??
By the way, though this does not invalidate anything you said, I might point out that another key functionality of POTH/ADH is that it provides middleman functionality. Of interest to me has been slaving dome rotation to the mount ( yes, my use of POTH has been a tangle of reasons). In using NINA, I am now able to let it do the dome slaving. This thread has clarified that, with Gemini, I no longer need POTH for connection sharing either ... awesome.
--
Edward
-- Brian?
Brian Valente portfolio
|
Re: ASCOM Device Hub or not
Paul, Thanks. Since I am not much concerned about TheSkyX, I will stick to my original question about Gemini driver.? To clarify, are you saying that Gemini always runs out of process as a DCOM service regardless of what client invokes it??
By the way, though this does not invalidate anything you said, I might point out that another key functionality of POTH/ADH is that it provides middleman functionality. Of interest to me has been slaving dome rotation to the mount ( yes, my use of POTH has been a tangle of reasons). In using NINA, I am now able to let it do the dome slaving. This thread has clarified that, with Gemini, I no longer need POTH for connection sharing either ... awesome.
--
Edward
|
I assume that most who are trying to fine-tune guiding are not using AO. As you say, there's little need to improve guiding if AO is making the corrections. Re-centering the star when it's getting out of frame doesn't have to be very precise, just close enough. The AO will take care of making precise corrections after the guider bump.
Regards,
? ? ?-Paul
toggle quoted message
Show quoted text
On Mon, Jun 14, 2021 at 02:40 AM, Les Niles wrote:
If you¡¯re imaging at 120 Hz, or even at 10 Hz, isn¡¯t the guiding immaterial? ?Guiding doesn¡¯t happen anywhere near that fast; any drift should be handled by the registration before stacking. ?For that matter, at 120 Hz it¡¯s hardly necessary to even track, except to keep the target from drifting out of the frame. ?
|
Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
One thing to realize is that Gemini has a greater internal precision than just one step. It reads stock servo encoders in quadrature, meaning it's capable of detecting an offset of 1/4 of a step size. For G11, one step is 0.5625 arcsec, so the actual offset can be detected with precision of up to 0.1406 arcsecs.?
Regards,
? ? ?-Paul
toggle quoted message
Show quoted text
On Sun, Jun 13, 2021 at 10:30 PM, Cyclone wrote:
The Gemini L4 manual states:
"In addition to support for Losmandy and Mountain Instruments mounts, Gemini L4 now?supports custom mounts. The user can setup the main parameters of his mount: the gear?ratios and direction of spur gear and worm gear and the servo motor encoder resolution.?The step resolution can reach from 0.1 arcsec per step (servo motor encoder tick) up to?2.5 arcsec/step."
The serial commands definition L5 v2.1 states:
"Gemini L4 supports step sizes from 0.2 arcsec/tick to 2.5 arcsec/tick."
Therefore it is unclear what the minimum step size is, but both definitions would support a 512 tick encoder assuming you do not modify the gearbox.
Also, I wrote a document a while ago that explains how to calculate the step sizes which you may find useful (see attached).
Eric
|
Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
Hmmmm Many thanks.....it odd considering the inner optical pick-up is AVAGO Broadcom but the rest looks US digital.
I still find it Not quite right.?? Each assy is the same......actually ..... looks to be the same...apart from code wheels
--
Brendan
|
If you¡¯re imaging at 120 Hz, or even at 10 Hz, isn¡¯t the guiding immaterial? ?Guiding doesn¡¯t happen anywhere near that fast; any drift should be handled by the registration before stacking. ?For that matter, at 120 Hz it¡¯s hardly necessary to even track, except to keep the target from drifting out of the frame. ?
toggle quoted message
Show quoted text
On 13 Jun 2021, at 13:50, Henk Aling < haling@...> wrote:
As a rule of thumb, without adaptive optics you will not get better resolution for apertures larger than 8".? So for visual, a 6" frac will be as good as a 12" SCT for almost every day of the year.? Of course resolution is not everything, light flux matters too.? For planetary observing imaging at 120+ Hz we depend on lucky seeing so the stacker picks the frames for which the Dawes limit matters.? So yes, it matters.
PS I made a mistake, 130/30 is not 0.25 but more like 0.4 but the conclusion remains that 0.7 is not good enough.
|
The answer might be location, location, location....
With east coast light pollution and the generally poor seeing from suburbia, the best I am getting is about 0.5" guiding around the zenith. Down at 30 degrees altitude about 1.0 guiding is average on a good night.? My 9.25 inch SCT is probably the most aperture local conditions will support. An 11" might be useable some of the time, but a 14" would probably be a fruitless effort for deep sky imaging. So even if I had super accurate mount, the air currents would probably bloat and distort the longer focal lengths and the cost of equipment wouldn't be worth it.?
Now if I had some Bortle 3 or less skies at some desert location with stable air, then the extra precision and investment in bigger and better equipment might be justified. And nearest dark sky site is about 4 hours away, so not a road trip that can be done on a regular basis with the larger equipment.
|
Michael Herman
David Malanick
Jamie Amendolagine
Paul Kanevsky
Edward Plumer