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Re: Offset Init & flip during SGP sequencing

paul K
 

perhaps my version of .95Gwin is not the same as your Martin?

When I tried to enter the track past meridian overlap value Sitech will not allow a number > 90 degrees The other values were allowed as per your image. If I try to enter 178, when I leave the field it reverts back to my original number which was 5.

Paul


Re: Offset Init & flip during SGP sequencing

paul K
 

if the cloud holds off Martin I'll give it a try with those settings tonight (U.K. time).
best wishes
Paul


Re: Offset Init & flip during SGP sequencing

MartinC
 

Hi Paul,
I've just thought about what you said & I think the dome movement is not so relevant here because it's under the control of SGP, not SiTech.

In my case the 2nd plate solve taking place without the dome moving is just 'collateral damage'. If I had a roll-on/roll-off roof or was in the open air it wouldn't matter because on the 2nd plate solve it would get a real image & slew back to where it should be.

I made a mistake in my previous reply. Instead of "Don's recommended settings" I mean't to say my original settings - that is the ones in the image I posted at the beginning of this thread.

But only if you have time.

I've been testing using the ASCOM Camera V2 Simulator. You can just enter your sensor details and load a jpg image taken with your camera from a previous occasion. So you can test regardless of conditions & even during the day if you choose an image of what's actually in the sky at that particular time.

Best wishes
Martin


Re: Meridian Limit and Unpark Question

Don W
 

Hi Josh,

I am finding out that 095P has some weird response to setting negative limits.  So be very careful with your settings and check those settings after you close ChangeConfig by opening ChangeConfig again.

When I set the West limit to -03:00:00, my East limit sets to -04:00:00 automatically (I can't change it).  With GEM Auto Flip Track unchecked, the mount will track to that -3 degree setting and stop.  This is what you want.

With GEM Auto Flip Go To checked, the mount will flip if you choose a target at less than 3 degrees EAST of the meridian.  I think you don't want that, so you just have to be careful.  You will control where the mount goes with GOTO's to avoid the ±3 degrees of the meridian.

I think this all will work for you, since you only track east to west (above the pole).

Good luck,
Don W

All of this is with the setting for Track Past Meridian Overlap set to zero.  If you don't have that = zero, then your mount will track past your -3 degrees.


Re: Offset Init & flip during SGP sequencing

MartinC
 

Hi Paul,
Many thanks for taking the time to test on my behalf, that's very kind of you. I imagine that as you have a conventional pier your meridian limits are pretty much default & I wonder what you'd find with the settings Don suggested to me earlier in this thread at #32847? If you do try this make sure you are in attendance just in case. Don't try it remotely.

I spent the whole weekend testing various scenarios with my settings, Dons recommended settings & the default settings. What I found was interesting but I have a few more checks to complete first before I post back.

Best wishes
Martin


Re: Meridian Limit and Unpark Question

Joshua Hufford
 

Thanks everyone. 

So if I understand it correctly, if I want the mount to stay 3 degrees away from the meridian on both sides all the way from north to south I would set the over the pole east and west limit to -03:00:00 and the under the pole to -177:00:00

Correct?

Was clear last night and able to do some testing for the first time under stars, pointing and tracking was pretty good. With no point model all objects across the sky were within at most 2/3 from center of a 910mm scope and 8300 chip. A rough measurement of the PE looks like about 12 arc seconds peak to peak. Seeing was not too good so I couldn't really nail down the guide settings but I was able to guide long enough to get good stars at 10 minutes of exposure. 

Next clear night I'm going to work on getting a point model created and hopefully refine the guider settings. 

Josh

On Sun, Apr 11, 2021 at 6:07 PM MartinC via groups.io <mncrane=virginmedia.com@groups.io> wrote:
No problem, it was good that there was a solution.

Best wishes
Martin


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I have decided "Push-to" control for my 14" Hubble Optics Dobsonian  and am selling the Si Tech Goto hardware and controls that I've written about in various forums, e.g., https://www.cloudynights.com/topic/448970-show-us-your-dobsonian/page-43

Original cost was $2544 = $1995 + $549 for added hand controller an battery hardware

I'm selling for a couple of reasons.  First, I've decided that I like my Dob to be fast and simple to set up, so I can spend maximum time observing visually.   The SiTech system is amazing, but adds weight and complexity, which I don't need for visual observation.  Second, I've already purchased an HNA  optics set from Tong (12" hyperbolic primary + 3.5" elliptical secondary +motor controlled 3.5 focuser with Rosin corrector) which I plan to put into a CarbonScobeTubes tube, following the plan of Paul Zelichowski's "Starbase" scope.  My plans suggest this should give me a 42mm fully corrected-illuminated field for astrophotography, in  ~40 lb. package that can be mounted on my G-11;  so I can use something like a QHY 367C color camera.

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I'm controlling the telescope with SiTechExe and Cartes du Ciel or Starry Night Pro. Once you have SiTechExe up and running, it reliably connects to the planetarium program. You can use a Surface tablet or PC to track, select and GoTo objects to observe; combined with the handpad (which doesn't interfere with the Bluetooth COM4 port on the Surface) you have a truly optimal wireless interface design. The hardware is 'observatory quality' and the software provides me with more flexibility and control than I could ever get with an 'off-the-rack' GoTo system.

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- Addressable! Many scopes on the same telescope field can use the handpad at once. No interference between scopes, and you won't be controlling the wrong scope!
- Instant Action! With the SiTech system, wired or wireless, there is imperceivable delay between the pressing of a button and movement of the scope! Great for centering objects without any overshoot!
- Built in auto guider port.

Bluetooth Serial Adapter

12V Battery Holder

12V to 24V DC converter


Re: Meridian Limit and Unpark Question

MartinC
 

No problem, it was good that there was a solution.

Best wishes
Martin


Re: Meridian Limit and Unpark Question

Don W
 

Hi Josh and Martin,

Yes, I see that 095P does allow negative limits.  I just tried setting the West limit to -5 degrees, and the mount stops tracking at 5 degrees before the meridian.

Josh this is your answer - it works!

Thanks Martin for trying this.

Don W


Re: Mesu 200 Mk2 Tracking stops close to equator

Jose Ignacio Sanchez Rodriguez
 

Hello Don,

Sorry it took some time to answer, but we are building at home adn this is a mess. I think you made a very good summary of the situation.
All mounts are prone to have problems, the important thing it to have the manufacturer by your side in order to solve them. As  users we need to offer the manufacturer some sort of evidence of the problem we claim we have. Given the nature of our hobby this might be a difficult and lengthy process. It is a well known fact that customers who have issues are more vocal about their experience with the product than customers who don´t have issues...I guess they are out there imaging, instead;) So I think it is easy to take things out of proportion and assume, out of a few cases, that these issues are general to the product. We are only looking at the numerator here. The denominator is hundreds of mounts out there that produce high quality images and make their owners very happy. Let´s not forget that.

There is a story from when Lucas first started to produce the MKI that involved a problem with a part from a third party supplier. Lucas ended up traveling around Europe to the affected owners houses to personally change the part and assure everything was ok. As I have mentioned before, so far the level of service I have received from Lucas has been at that level. So even if I´m not at a happy place right now, I feel confident we´ll find a solution.

Thanks all for your help and have a nice week,

Jose


Re: Meridian Limit and Unpark Question

MartinC
 

Hi Josh,

I don't mean to intrude but I'm currently looking at a different issue I have with Meridian limits - hence my interest in your question.

I believe you can stop your tracking before the meridian. I have just tried it on my mount.

Since version 95M you have the ability to set the meridian limits anywhere, pos or neg. You can also set the tack past limit to any positive number but not negative.

So I've set mine as per the attched images & it works. I'm sure you can experiment to suit your exact needs. I've not tried for Under the pole but I gues the same will apply.

Hope this helps

Best wishes
Martin


Re: Meridian Limit and Unpark Question

Joshua Hufford
 

Hi Don, I'm using a longer scope now that I was previously, and with my large 8 position filter wheel if I track all the way to the meridian my wiring gets awfully tight at the pier, might have to figure out something different, however a 3 degree limit on each side gives a decent amount of a safe zone. 

Thanks for the explanation of the Park, it seemed to work fine. I just didn't remember getting that message before. 

Looking forward to hopefully posting some new images soon. 

Josh

On Sun, Apr 11, 2021 at 2:21 AM Don W <westergren@...> wrote:
Hi Josh,
It is good to hear from you again. In answer to your question about stopping tracking before the meridian, I think the answer is NO.  Why do you want to do this - maybe there is a work-around?

The latest SiTech is 095P at:
http://siderealtechnology.com/SiTechSetup095P.exe

SiTech records a note in the SiTech.cfg file about the park situation.  All that is - is a 0 for not parked and a 1 for parked.  when you start up SiTechexe, it simply reads that cfg file entry, but that really doesn't do anything.  If the mount is in your park position, then go ahead and UNPARK.

Don W


Re: Meridian Limit and Unpark Question

Don W
 

Hi Josh,
It is good to hear from you again. In answer to your question about stopping tracking before the meridian, I think the answer is NO.  Why do you want to do this - maybe there is a work-around?

The latest SiTech is 095P at:
http://siderealtechnology.com/SiTechSetup095P.exe

SiTech records a note in the SiTech.cfg file about the park situation.  All that is - is a 0 for not parked and a 1 for parked.  when you start up SiTechexe, it simply reads that cfg file entry, but that really doesn't do anything.  If the mount is in your park position, then go ahead and UNPARK.

Don W


Meridian Limit and Unpark Question

Joshua Hufford
 

Hello everyone, after a hiatus from imaging do to mount motor failure and just general life getting in the way I'm getting my imaging setup back up and running again. My MI-250 is now running with Pittman 9000 series servo motors instead of the stock Losmandy Gemini motors, should be a big improvement. 

First question about the meridian limit, is there a way to prevent the mount from tracking a few degrees before it hits the meridian? I tried entering a negative number in the meridian overlap setting, however it wouldn't accept it. I'd like to have my mount stop tracking three degrees before the meridian if possible. I'm guessing the Meridian Limit east and west boxes are where I would set this, but I'm not exactly sure what I need to input here. 

Also I have my park position set, however when I click UnPark I get a message saying the scope is not officially parked. Any idea why that is?

Lastly I'm running version .94N. Is this the latest version? If not what is? 

Thanks!

Josh


Re: Offset Init & flip during SGP sequencing

paul K
 

Hi Martin, I had some clear tonight so at 10 pm I set up M95 (east of meridian at that time) as a sequence in SGP.

On this occasion in Sitech I set the scope horizontal pointing Az 90 and parked it there. So my process was as follows:

unpark the mount (I used Sitech interface to do this)
In SGP, tick slave dome to scope, then in target settings click 'Centere now'

Findings:

Scope moves quite quickly to target (as usual for me) - no pier flip.
Dome takes a while to catch up and before it does, SGP's centre now routine is taking an image of the inside of my dome.

I repeated this process three times with the same result each time.

So that wasn't particularly useful, it's similar to what you found, but I had no pier flip from Sitech up to that point of failure.

If it's clear again tomorrow night I'll park at Az 270 and centre on a target west of the meridian to see if the same happens on the west side.

I must admit I'll be surprised if it fails to wait on the west side as that's where I image mostly, and I'm sure I'd have spotted the problem before. I will check though.

Also tomorrow I'll post a pic of my mount parms dialog from Sitech.

Best wishes
Paul


Re: Offset Init & flip during SGP sequencing

MartinC
 

Hi JonK,
I also agree that imaging under the pole can be of interest and should be straightforward with a bent knee pier.

One thing I've noticed if you set your limits on top of each other is that the RA axis gently oscillates at the end of a slew instead of tracking. Like a PID controller that's not quite tuned.

If you don't mind being weights up then perhaps you could take it out of GEM mode. That will get rid of the limit settings.

Unfortunately for dimensional and spacial reasons I need to be weights down when begin to image; be that in the East or the west. Which means that ultimately Don's suggested settings won't work for me if I choose to begin imaging looking west. I need the mount to function as a GEM.

But I'm going to try Don's settings to check if they illuminate the unwanted slewing during plate solving in the east. Either way it will be an important test.

I shall also try with APT instead of SGP, a different plate solver and a different camera. That should rule in\out any possible equipment compatibility issues.

I shall also test using the ASCOM camera simulator. You can load an image into it and run a real sequence which means I can test during the day.

Hopefully soon I'll have some test results.

Best wishes
Martin




Re: Offset Init & flip during SGP sequencing

Jonk
 

I'd like to agree with MartinC and Paul K.

I also have a bent knee pier, designed mainly to avoid meridian flips and any possibility of crashes, and I asked the question about setting limits before on a separate thread.

What I have done is set all limits to +/- 180 degrees, essentially moving everything to be between the ncp and the N horizon. I know this will probably be frowned upon, but in testing this appears to be all I can do to 'remove limits'.

I would like to see a simple switch in the software, turning limits off, with a simple pop up message 'are you sure, damage may result if incorrectly used' or similar, as is in use on other mount control systems I have seen. This would cater for people who do have the possibility of a pier crash.

I also disagree with the comment above about not imaging under the pole - ok, for people with a pier crash possibility, this is sound advice, but people have to take responsibility for their own actions. For people without this issue, there's no reason not to - ok, it's not abundant with targets for imaging, but take last year for example - Comet Neowise - a perfect example of set in the NW and rise in the NE. My observatory location has a fairly good NW to NE view so I would certainly look to be pointing in that area.

But, it's not always about imaging - I am an occasional observer and with my large refractor, I simply remove the imaging gear and fit a diagonal and eyepiece. If I want to point to the N, which I probably will do frequently as it's the darkest part of sky for me and is probably my best horizon taking into account the low skyline and lack of serious light pollution, then the advice of 'don't image' (or observe) under the pole doesn't work for me. Especially with a bent knee pier. Again, Comet Neowise would be a perfect example.

Regarding the initial error discussed about the plate solve then the mount slewing to a mirror opposite without any input from SGP, I am very interested to see if this is a bug. Unfortunately, my equipment is not set up so I can't run my Mesu e200 / SGP combination to see if it does the same, but look forwards to the resolution.

In conclusion, a 'switch off mount limits' button would be great, as I don't really care whether I am weights up or down for the majority of what I want to do.


Re: Mesu 200 Mk2 Tracking stops close to equator

Don W
 

Hi Paul,
Slippage anywhere in the drive is bad.  All slippage is dependent on the load and the level of friction.  Slippage is by definition when the friction is overcome and the two parts allow movement when you don't want any movement there.

So Slippage can be the friction drive wheel (like the Mesu Mount drive), it could be a set screw in a coupling or belt drive hub, or as Chuck mentioned the output drive gear in Pittman Servos is staked to the output shaft. Any and all of these cases "could" occur in a localized place in the sky - for instance due to balance where in part of the sky the motion is working against the balance load.  The cause of slippage doesn't know or care where you are pointing in the sky - it just slips when the friction isn't enough.

Generally the SiTech servos will be applying torque when tracking similar to when slewing.  The acceleration and deceleration of a heavy and especially a long refactor (lots of moment of inertia) is where the loads on the drive are higher.  If slippage is marginal during acceleration then SiTech can be set to reduce the acceleration forces.

Don W


Re: Mesu 200 Mk2 Tracking stops close to equator

paul K
 

Just to ask the question to try to help, would the slippage Chuck describes be positional as per Jose's problem? Or given the gearing ratio (motor to mount)  would it be more evident i.e not just one place in the sky?

Paul


Re: Mesu 200 Mk2 Tracking stops close to equator

Don W
 

Hi Chuck and all,
Chuck has a good point that slippage might be IN THE SERVO.  But that would also affect slewing.

A test for this (or any slippage) would be to slew between two stars (about 10 degrees or more apart) with a camera recording the positions at each star.  Do this a few times and the images will confirm if there is any slippage.
Don W

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