3868 replies to this topic

[Nayin]

I'm wondering whether to buy the TS ED 102mm f / 7 or better go for the ED 80 for visual use only and with the AZ-GTI.

Can someone share their experience with a tube of these characteristics?

[Albut]

I'm wondering whether to buy the TS ED 102mm f / 7 or better go for the ED 80 for visual use only and with the AZ-GTI.

Can someone share their experience with a tube of these characteristics?

Look at #2504. It cope easily with my Televue TV-85. Thats about 3.8Kg with star diagonal. 

[Nayin]

Look at #2504. It cope easily with my Televue TV-85. Thats about 3.8Kg with star diagonal. 

I know that with an 80 it works well, I doubt if it would also do it with a 100 f7.

[Gazpacho]

There is a thread for those that tried an Orion 120st on their AZ-GTi mount.  I am seriously considering the TS 102mm SD-APO Doublet, but I doubt it would be any better than my Celestron C5.

 

https://www.cloudyni...good/?p=9103097

[lpalbou]

Thanks for the information it was really useful.

I would also add to your list the Skywatcher adventurer pro. I have used it and the ioptron skyguider pro side by side more than once and for astrophotography tracking there really isn’t any difference. Both have their good and bad points but do a fairly good job. Polar alignment is crucial but can be performed adequately with the installed polar scopes and both can be guided.

I didn't mention the skywatcher adventurer pro, which is indeed the competitor of the skyguider pro... but because from everything I've read, the skyguider pro is more precise and has less PE peak to peak. You are right it's not a huge difference, but usually people says that you can image up to 300mm with the skywatcher and up to 400mm with the skyguider.. One thing though is the clutch for the RA axis of the skyguider pro is really not great... so you absolutely have to balance your setup (which you should anyhow) to avoid surprises.. the skywatcher seems much better in that aspect.

 

Two additional notes regarding the AZ GTI:

- I do use the ADM saddle, feel much more robust even though overkill for such a small mount. Also note this is a vixen saddle so if you wanted to use your usual camera dovetail, you can't with ADM

- Wifi: I used to have issues from time to time, especially when it was cold and humid on top of hills. I've had about 1/2 nights ruined like that, but not more. I do use now the lynx cable to pilot the mount, but it was more to use EQMOD

[Albut]

I’m looking at polar aligning my az-gti with the use of old polar scope I have rather than electronically. I’ve seen the attached for sale and wonder if anyone has any experience with it.

What I can’t understand is how can it get accurate alignment when it’s not through the centre axis where the mount rotates as is normal in most eq mounts. Normally on my eq5, I would align my polar scope to the mount (to get it parallel) by rotating it 180 deg and adjust the set screws and repeat process until it stayed on same spot. The normal way. Here it’s off to the side so how is that achievable. And even if I managed to get it aligned to the mount (ie parallel to the axis of rotation), if I then polar align by getting Polaris in the polar scope correct point surely the central axis isn’t. I just can’t see how it could work. Perhaps it doesn’t matter I just don’t understand it. Any help or explanation appreciated.

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[CloudyIFR]

Explorer1, I use that same attachment and it works great!  I would caution to remove it after alignment as I had it bind once and I could hear the gears doing very bad things trying to force the mount to move where I had told it to.  I do a rough alignment with this as in I put it where the an app tells me the NCP should be in relation to Polaris, perform a three star alignment and then I've had great success!  One of the tricks with the SynScan app that seems weird but works is once the mount is powered on and you're pointing at Polaris, run the app then select Reset Alignment, throw the app away and then start with the 3 star alignment.

Curtis

[Albut]

Explorer1, I use that same attachment and it works great!  I would caution to remove it after alignment as I had it bind once and I could hear the gears doing very bad things trying to force the mount to move where I had told it to.  I do a rough alignment with this as in I put it where the an app tells me the NCP should be in relation to Polaris, perform a three star alignment and then I've had great success!  One of the tricks with the SynScan app that seems weird but works is once the mount is powered on and you're pointing at Polaris, run the app then select Reset Alignment, throw the app away and then start with the 3 star alignment.

Curtis

When you say run the app, do you mean do a star alignment?

[CloudyIFR]

When you say run the app, do you mean do a star alignment?

Correct, the SynScan app.

[Albut]

Correct, the SynScan app.

Thanks I’ll give it a try.

[nik282000]

I received my GTi a few weeks ago and as is tradition, I have enjoyed snow, rain, and fog ever since.

 

In the meantime I got curious about the power consumption so I hooked up a combination volt/amp meter and ran the mount through a few movements.

 

I was using an 8aH 12v, sealed battery to power the mount and chose speed 7 as it drew significant current while being slow enough to let the readings settle down. For the scope and weight I had a Celestron 102GT (3.08Kg) and a Star Adventurer counterweight + DIY M12->M8 adapter (1.34kG) on the mount and it as balanced best I could. Each movement was ~90 degrees, starting with the scope pointing to the north pole and then returning to that position.

 

Seems to me that the mount uses only a little more current with the scope than without when slewing and that my 8AH battery should keep me going for ages. The two GOTO movements (speed 9) that are off the scale drew 300-350mA.

 

Also, from the looks of spikes in the 'weight moving down,' there may be an oblong, intermediate gear in my RA axis. The period is too long for it to be the motor and too short to be the big ring gear.

 

[ShropshireLad]

@CloudyIFR can you explain this part please

Quote " pointing at Polaris, run the app then select Reset Alignment, throw the app away and then start with the 3 star alignment."

 

Thanks 

[gpaunescu]

I have this system with polar finder.

I do roughly polar positioning of the mount; next I check the position of the polar star where should be positioned on reticle, when I look through polar finder (I use a mobile application to find out where should be the polar ex. Polar Alignment or Polar Clock on Android). Next I do star alignment.

 

Another method, if the polar star is not visible, I described in post # 2561

 

https://www.cloudyni...3#entry10861163

[Albut]

Explorer1, I use that same attachment and it works great!  I would caution to remove it after alignment as I had it bind once and I could hear the gears doing very bad things trying to force the mount to move where I had told it to.  I do a rough alignment with this as in I put it where the an app tells me the NCP should be in relation to Polaris, perform a three star alignment and then I've had great success!  One of the tricks with the SynScan app that seems weird but works is once the mount is powered on and you're pointing at Polaris, run the app then select Reset Alignment, throw the app away and then start with the 3 star alignment.

Curtis

Can you tell me how you calibrated your polar scope to the mount as I presume off axis. Thanks

[ANKry]

Can you tell me how you calibrated your polar scope to the mount as I presume off axis. Thanks

With this device, it is not possible to calibrate the pole finder and the polar axis of the mount, since the pole finder and the mount are not attached to a common platform. The polar axis rotates independently of the pole finder. How to calibrate the off-axis pole finder can be found in posts 2404 and 2432.https://www.cloudyni...i-mount/page-97

[CloudyIFR]

Can you tell me how you calibrated your polar scope to the mount as I presume off axis. Thanks

In my experience close enough is good enough with the mechanical polar alignment. I make sure the tripod is level in both axis with a bubble level.  Then I level the mount on the tripod with the same bubble level in both axis.  To speed things up I have a laser on a hot shoe and point it at Polaris.  I actually think this is close enough as the three star alignment is quite good telling the electronics what to do.  However, I look through my polar finder and get Polaris near the NCP using an app that tells me where it should be.  Remove the polar scope so it doesn't bind.  Then I turn the mount on and run the SynScan app.  I connect to the mount and then select Alignment - Reset Alignment.  Throw the app away.  Repeat but this time when selecting Alignment I choose three star alignment.  I think it's very important to perform the three star alignment as you get one star on one side of the Meridian and two stars on the other side.  During each star alignment I zoom in Live View and center that star.  It's interesting that at times I'll find one star way off but I just center it and move on and it doesn't seem to matter.  I've been able to achieve 2min subs with no trailing over a 3 hour period.  

Hope this helps.

Curtis

[Albut]

With this device, it is not possible to calibrate the pole finder and the polar axis of the mount, since the pole finder and the mount are not attached to a common platform. The polar axis rotates independently of the pole finder. How to calibrate the off-axis pole finder can be found in posts 2404 and 2432.https://www.cloudyni...i-mount/page-97

Thanks for the info but neither of these post cover how to align an off-axis polar scope only how to instal one. Once installed, say as shown how do you align it? Being off axis if you align the normal method the polar scope cannot be parallel to the RA axis as some say. It must converged towards the RA axis at an angle dependant upon the distance of the centred object. So aligning in the normal way on a closer object will result in error. 

[Albut]

In my experience close enough is good enough with the mechanical polar alignment. I make sure the tripod is level in both axis with a bubble level.  Then I level the mount on the tripod with the same bubble level in both axis.  To speed things up I have a laser on a hot shoe and point it at Polaris.  I actually think this is close enough as the three star alignment is quite good telling the electronics what to do.  However, I look through my polar finder and get Polaris near the NCP using an app that tells me where it should be.  Remove the polar scope so it doesn't bind.  Then I turn the mount on and run the SynScan app.  I connect to the mount and then select Alignment - Reset Alignment.  Throw the app away.  Repeat but this time when selecting Alignment I choose three star alignment.  I think it's very important to perform the three star alignment as you get one star on one side of the Meridian and two stars on the other side.  During each star alignment I zoom in Live View and center that star.  It's interesting that at times I'll find one star way off but I just center it and move on and it doesn't seem to matter.  I've been able to achieve 2min subs with no trailing over a 3 hour period.  

Hope this helps.

Curtis

Thanks Curtis I’m looking at something like shown in the best option here:https://www.amateura...om/az-gti-mount

I just can't see that the off-axis polar scope can be parallel to the RA axis as described. It must converge towards the RA axis when collimated and that convergence point will be dependant upon the distance of the object being centred in the polar scope. Then rotating 180 deg if the point stays in the centre it’s done but the polar scope axis will converge at the RA axis in both 180 deg directions.  This is the only way I can see it being effective. Not able to get an answer on this from anyone.

[ShropshireLad]

In my experience close enough is good enough with the mechanical polar alignment. I make sure the tripod is level in both axis with a bubble level.  Then I level the mount on the tripod with the same bubble level in both axis.  To speed things up I have a laser on a hot shoe and point it at Polaris.  I actually think this is close enough as the three star alignment is quite good telling the electronics what to do.  However, I look through my polar finder and get Polaris near the NCP using an app that tells me where it should be.  Remove the polar scope so it doesn't bind.  Then I turn the mount on and run the SynScan app.  I connect to the mount and then select Alignment - Reset Alignment.  Throw the app away .  Repeat but this time when selecting Alignment I choose three star alignment.  I think it's very important to perform the three star alignment as you get one star on one side of the Meridian and two stars on the other side.  During each star alignment I zoom in Live View and center that star.  It's interesting that at times I'll find one star way off but I just center it and move on and it doesn't seem to matter.  I've been able to achieve 2min subs with no trailing over a 3 hour period.  

Hope this helps.

Curtis

Hi Curtis .... When you "throw the app away" do you also switch off the mount or not ??

Edited by ShropshireLad, 24 February 2021 - 11:04 AM.

[ANKry]

Thanks Curtis I’m looking at something like shown in the best option here:https://www.amateura...om/az-gti-mount

I just can't see that the off-axis polar scope can be parallel to the RA axis as described. It must converge towards the RA axis when collimated and that convergence point will be dependant upon the distance of the object being centred in the polar scope. Then rotating 180 deg if the point stays in the centre it’s done but the polar scope axis will converge at the RA axis in both 180 deg directions.  This is the only way I can see it being effective. Not able to get an answer on this from anyone.

Everything is obvious! Use the polar star to collimate the polar finder and the polar axis. And then the distance between the polar axis and the polar finder will not matter.

[Albut]

Everything is obvious! Use the polar star to collimate the polar finder and the polar axis. And then the distance between the polar axis and the polar finder will not matter.

Thats what I thought. That’s a nuisance not able to collimate by day then as with my eq5 on a distant object. As you must do it on Polaris else, as the axis is off to the side anything closer would cause an error.

[ANKry]

Thanks Curtis I’m looking at something like shown in the best option here:https://www.amateura...om/az-gti-mount

 

The option is the same as mine, only made of plastic. Mine is made of duralumin and is more rigid.

[Albut]

The option is the same as mine, only made of plastic. Mine is made of duralumin and is more rigid.

Yep, yours look pretty good. If you ever start up making them let me know and I’ll put in my order.

[ANKry]

Thats what I thought. That’s a nuisance not able to collimate by day then as with my eq5 on a distant object. As you must do it on Polaris else, as the axis is off to the side anything closer would cause an error.

You can also use terrestrial objects. The distance is about a kilometer, more than enough. The error will be negligibly small.

[ANKry]

Yep, yours look pretty good. If you ever start up making them let me know and I’ll put in my order.

I did it only for myself, when I had the opportunity to use the equipment of a mechanical workshop. There is no such possibility now.