Skywatcher AZ GTI mount owners thread

[bomberbaz]

13 minutes ago, LaurenceT said:

I don't think you can get more levelling accuracy than using a bubble level, some seem to think that the mount is reasonably forgiving in terms of level accuracy.

You could always buy an electronic leveller but I suspect that there would be little discernable difference.

 

I have an electronic altimeter, works a treat.

[Zermelo]

 

On 26/02/2022 at 00:33, OK Apricot said:

So I'm out with the scopes at the moment and things aren't too bad, but could be a lot better. I took my time making sure the spirit bubble on the GTi was near enough centred with one leg pointing north. I the used the scope to point the mount north by centring Polaris, and levelled the scope with a spirit level.i can't get the position sensor to work on the app - as soon as I turn it on, the app crashes and my phone goes to home screen. Tried both versions from play store. Anyway, managed to get some meaningful GPS coordinates, so started off with a level North alignment.

It actually wasn't too bad by the second star. I chose Arcturus and Betelgeuse as they're opposite sides of the sky. Arcturus was a mile out, but having manually centred and slewed to Betelgeuse, it was pretty close - not in the FOV but not far out. I went to a few other stars to try to get the mount to "learn" where its pointing (making the adjustments and confirming), after around 12 different attempts, it put its first star in the eyepiece. Tracking isn't too bad, drifting noticeably over half an hour. Think I'm on the right track. 

Looks like high cloud is going to put an end to tonight. 

There's disagreement about how important levelling and North pointing are, given that the software is supposed to correct for that, but I always try to do it as close as I can. It gets a lot easier with practice.

Have you ready the Synscan manual advice on star selection? For azimuth, you should try to get two stars that are approximately 90 degrees apart.

36 minutes ago, OK Apricot said:

So last night was slightly better - a couple objects were actually in the eyepiece but still somewhat hit and miss. Must be on the right track 🤔 I think it's about as good as its going to get without using an illuminated reticle eyepiece for more accuracy? When manually centring I'm using slew speed 5 - I could probably slow that down to be more accurate and make sure the up/right movements are actually taking up the backlash? I'm not sure how much more level I can get it according to the bubble level - there's a lot of room for error. 

An illuminated reticle eyepiece does make it easier, though when you're starting out it can seem difficult to justify the expense for something you use only when you're setting up. Failing that, use the trick of defocusing so that the target star fills up most of the FOV, then it's easier to tell when it's centred.

I have a different mount, but when I'm doing the last bit of centering I dial the speed down as slow as I can - 2 or even 1. If the star is drifting fast, you may need a higher speed and some good judgement.

Definitely follow the advice on finishing up and right to take out the backlash. In fact, Synscan won't let you confirm if you don't.

 

 

 

[ScouseSpaceCadet]

46 minutes ago, OK Apricot said:

So last night was slightly better - a couple objects were actually in the eyepiece but still somewhat hit and miss. Must be on the right track 🤔 I think it's about as good as its going to get without using an illuminated reticle eyepiece for more accuracy? When manually centring I'm using slew speed 5 - I could probably slow that down to be more accurate and make sure the up/right movements are actually taking up the backlash? I'm not sure how much more level I can get it according to the bubble level - there's a lot of room for error. 

If you haven't tried this already, to improve accuracy, when the alignment star is roughly centred, swap to a higher power eyepiece to complete alignment.

 

[AstroNebulee]

2 hours ago, OK Apricot said:

So last night was slightly better - a couple objects were actually in the eyepiece but still somewhat hit and miss. Must be on the right track 🤔 I think it's about as good as its going to get without using an illuminated reticle eyepiece for more accuracy? When manually centring I'm using slew speed 5 - I could probably slow that down to be more accurate and make sure the up/right movements are actually taking up the backlash? I'm not sure how much more level I can get it according to the bubble level - there's a lot of room for error. 

Was it any better using the new downloaded software? Maybe see if anyone has an el cheapo device to use or buy cheaply. 

I used to use a spirit level on my mount, scope and tripod as I think the spirit bubble on my tripod and mount were off and very badly put in. 

Edited February 27, 2022 by AstroNebulee

[AstroNebulee]

3 hours ago, ScouseSpaceCadet said:

It is a beauty indeed. I'm glad I kept mine despite waivering for months. The AZGTI saw use today for the first time since last July. Solar observing using a Skymax 127, filter and solar finder. The 24mm Altair UFF presents a solar disc with room to spare. I had a good look at the latest sun spots.

Beautiful set up, she's a beauty when observing and imaging the sun 😊

[OK Apricot]

So I feel like I'm starting to learn my way around this mount. 

It's clear again so I got everything out. Took my time leveling the mount head using the tripod legs (ignoring tripod spirit bubble) as its the mount itself that needs to be level. I pointed north, leveled the OTA and turned on the mount. 

 

I checked location was on and correct, that the axis readings were zero'd, andthat the encoders were switched on, as I'd read this can help improve accuracy. 

 

I began a 3 star alignment - Betelgeuse, Castor and Polaris. Not taking much notice of the accuracy at this point, just making sure to get the star in FOV, swapping to higher power and defocusing to find centre. While making the manual adjustments, I was sending the star to the "top right" of the FOV, then turning down the slew speed to 2, so that I could accurately place the star in the centre using nothing but the up and right adjustment (not to overshot and have to use other directions). I noticed the delay between pressing to slew and the mount actually moving the scope, so I'm learning this is the backlash. First time round the alignment failed, so I just did the same again and it stuck. From Polaris to Betelgeuse it's practically the opposite side of the sky, but it was actually pretty close, with B right at the tip of the FOV. I made the adjustments again by increasing magnification and sending it to the top right so I could centre it using only up and right motions. Jumping from star to star gave some actually quite respectable results this time, and the tracking was faultless. A little more accuracy would be nice, but the more I learn the mount, the better it's becoming. 

Cheers for the help guys, excellent thread. 

Edited February 27, 2022 by OK Apricot

[badhex]

10 hours ago, OK Apricot said:

So I feel like I'm starting to learn my way around this mount. 

It's clear again so I got everything out. Took my time leveling the mount head using the tripod legs (ignoring tripod spirit bubble) as its the mount itself that needs to be level. I pointed north, leveled the OTA and turned on the mount. 

 

I checked location was on and correct, that the axis readings were zero'd, andthat the encoders were switched on, as I'd read this can help improve accuracy. 

 

I began a 3 star alignment - Betelgeuse, Castor and Polaris. Not taking much notice of the accuracy at this point, just making sure to get the star in FOV, swapping to higher power and defocusing to find centre. While making the manual adjustments, I was sending the star to the "top right" of the FOV, then turning down the slew speed to 2, so that I could accurately place the star in the centre using nothing but the up and right adjustment (not to overshot and have to use other directions). I noticed the delay between pressing to slew and the mount actually moving the scope, so I'm learning this is the backlash. First time round the alignment failed, so I just did the same again and it stuck. From Polaris to Betelgeuse it's practically the opposite side of the sky, but it was actually pretty close, with B right at the tip of the FOV. I made the adjustments again by increasing magnification and sending it to the top right so I could centre it using only up and right motions. Jumping from star to star gave some actually quite respectable results this time, and the tracking was faultless. A little more accuracy would be nice, but the more I learn the mount, the better it's becoming. 

Cheers for the help guys, excellent thread. 

Couple of thoughts here @OK Apricot 

1. With my AZ-GTi in Alt-Az mode, it's basically impossible to level using the bubble on the mount itself. Even if I'm perfectly level, if I then rotate the mount on the AZ axis, the bubble is way off. Try levelling yours using the mount bubble level and then unlock the az clutch adn rotate it to see if the bubble stays level. Even though it's counter-intuitive (as you said, the mount should be level not the tripod) I have only ever been successful when levelling using the tripod bubble level.

2. I don't use a three-star alignment, as the north-level is way quicker and usually pretty accurate straight away. It will continually improve over the next few objects as you always have the 'center object' dialogue after each slew. I tend to find after the 3rd or maybe 4th object it's perfect. 

3. The auxiliary encoders are very helpful (read: essential) if you want to manually move the scope for whatever reason by unlocking the clutches, but in general you don't need to turn them on if you're only ever using the app or hand controller to point the scope, and apparently they actually reduce accuracy. According to skywatcher:

"If an user does not need to rotate the mount manually after alignment, it is recommended to disable this feature to obtain the best pointing accuracy." 

All of that said, I often turn them on and have seen no appreciable negative effect on accuracy. 

 

Apologies if any of this has already been said or if it clashes with other advice; advice is based on my own experience of the AZ-GTi over the last year or so, so as always your experiences may be different. It may be worth trying the tripod levelling/North level trick just to see if it helps. 

 

[OK Apricot]

Thanks, badhex. Very good point to rotate the mount actually, I will do that next time and see if there are improvements. I noticed on the app my alt/az readings are not zero, is this supposed to be zero when indicating perfect level? 

[badhex]

28 minutes ago, OK Apricot said:

Thanks, badhex. Very good point to rotate the mount actually, I will do that next time and see if there are improvements. I noticed on the app my alt/az readings are not zero, is this supposed to be zero when indicating perfect level? 

No problem. With the rotating tip, it's more to see whether the mount bubble level stays level. Try and see - if it doesn't, then try levelling just using the tripod to see if you get a better result. RE the readings on the app - good question! Theoretically both axes should reset to zero after doing the first step of north level, however you don't actually see this as obviously you then go on to further align two more objects. It may also be that it holds the values in temporary memory and only 'commits' them once you've completed the alignment process - not sure.

[AstroNebulee]

4 hours ago, badhex said:

I don't use a three-star alignment, as the north-level is way quicker and usually pretty accurate straight away. It will continually improve over the next few objects as you always have the 'center object' dialogue after each slew. I tend to find after the 3rd or maybe 4th object it's perfect.

Plus 1 for this @OK ApricotI always used to align this way and was very accurate indeed. 

[Adam J]

Can anyone tell me what the input voltage for the main board on the AZ GTI is? I recently damaged mine and I now have a replacement, but I dont want to connect it until I have made sure that the voltage regulator on the interface board that sits between the battery and the main board has not also been damaged. 

Many thanks in advance. 

Adam 

[AstroNebulee]

29 minutes ago, Adam J said:

Can anyone tell me what the input voltage for the main board on the AZ GTI is? I recently damaged mine and I now have a replacement, but I dont want to connect it until I have made sure that the voltage regulator on the interface board that sits between the battery and the main board has not also been damaged. 

Many thanks in advance. 

Adam 

Here on flo website its 7.5v-14v 0.75a, I use a 12v power supply via an AAP and previously used a 12v talentcell battery pack. 

Cheers 

Lee 

Edited February 28, 2022 by AstroNebulee
Added image

[Adam J]

2 hours ago, AstroNebulee said:

Here on flo website its 7.5v-14v 0.75a, I use a 12v power supply via an AAP and previously used a 12v talentcell battery pack. 

Cheers 

Lee 

Yes I think that the 7.5-14 volt is the input voltage am assuming that the internal electronics (motor driver board) are operating at a fixed voltage near the bottom end of that range after passing through a voltage regulator. 

Adam 

[AstroNebulee]

3 hours ago, Adam J said:

Yes I think that the 7.5-14 volt is the input voltage am assuming that the internal electronics (motor driver board) are operating at a fixed voltage near the bottom end of that range after passing through a voltage regulator. 

Adam 

Probably worth sending an email to skywatcher or flo maybe they can confirm but should be OK 👍

Edited February 28, 2022 by AstroNebulee

[RayWUK]

I had a reasonable imaging session the other night as it was the first clear night i've had since purchasing the AZ-GTI. I was hoping to image Orion Nebula but it was going to be obscured from garden for a few hours and as i didn't want to waste imaging time i elected to image the Heart Nebula. I got just over 2 hours in of 66 x 120secs subs. Guiding was mainly ok at about 1-2 arcsec RMS which was within my imaging scale of 3.5 arcsec using the Redcat and Canon 600D.

However after stacking and a quick post process i was a bit disappointed with the result. It all looked a bit noisy. Still i'm very new at this game so i'm hoping there's more to be had once i get my head around what i'm supposed to be doing.

Looks like it might be another clear evening so i'm thinking of collecting some more subs of the same image rather than trying something else.

Edited March 1, 2022 by RayWUK

[AstroNebulee]

55 minutes ago, RayWUK said:

I had a reasonable imaging session the other night as it was the first clear night i've had since purchasing the AZ-GTI. I was hoping to image Orion Nebula but it was going to be obscured from garden for a few hours and as i didn't want to waste imaging time i elected to image the Heart Nebula. I got just over 2 hours in of 66 x 120secs subs. Guiding was mainly ok at about 1-2 arcsec RMS which was within my imaging scale of 3.5 arcsec using the Redcat and Canon 600D.

However after stacking and a quick post process i was a bit disappointed with the result. It all looked a bit noisy. Still i'm very new at this game so i'm hoping there's more to be had once i get my head around what i'm supposed to be doing.

Looks like it might be another clear evening so i'm thinking of collecting some more subs of the same image rather than trying something else.

Definitely more integration time will make your 8mage better and less noisy too. Your guiding rate is good for the mount, hopefully you get your clear night tonight, good luck Ray and keep going, as I have found there are good times and bad with imaging and the good times certainly make you forget the bad times 👍

[Elp]

@RayWUK did you take and apply all your calibration frames as that helps a lot. I've got a 600d too and find it noisy, but then again so is my zwo in smaller pixels.

[powerlord]

2 hours ago, RayWUK said:

I had a reasonable imaging session the other night as it was the first clear night i've had since purchasing the AZ-GTI. I was hoping to image Orion Nebula but it was going to be obscured from garden for a few hours and as i didn't want to waste imaging time i elected to image the Heart Nebula. I got just over 2 hours in of 66 x 120secs subs. Guiding was mainly ok at about 1-2 arcsec RMS which was within my imaging scale of 3.5 arcsec using the Redcat and Canon 600D.

However after stacking and a quick post process i was a bit disappointed with the result. It all looked a bit noisy. Still i'm very new at this game so i'm hoping there's more to be had once i get my head around what i'm supposed to be doing.

Looks like it might be another clear evening so i'm thinking of collecting some more subs of the same image rather than trying something else.

care to share ? with orion that should be plenty to get a decent pic. With heart nebula maybe not so much - it is a lot dimmer. though you do have the benefit that it's ALT is much higher so less light pollution - but I shot heart and soul the other night in NB with my asi1600 with 600s exposures and it was still rubbish.

[RayWUK]

@powerlord here it is. I didn't manage any further subs as it turned out too cloudy. I made use of the time to shoot off 50 more dark frames this time at the same temp as the subs. I'm also not convinced my flats are up to much either so I'm going to redo them as well tonight.

IC1805_Heart_Nebula.tiff

Edited March 2, 2022 by RayWUK

[Elp]

The stars look fairly round so it's done good tracking I think. You'll struggle taking flats now as they're supposed to be taken whilst your setup is still out as if you were taking light frames as the camera temperature, orientation, focus position, any dust on lenses filters etc all have to be the same and unaltered. Did you also take bias frames?

[RayWUK]

1 hour ago, Elp said:

The stars look fairly round so it's done good tracking I think. You'll struggle taking flats now as they're supposed to be taken whilst your setup is still out as if you were taking light frames as the camera temperature, orientation, focus position, any dust on lenses filters etc all have to be the same and unaltered. Did you also take bias frames?

Yes, i did take bias frames along with the flats. Looking at the jpg of the flats makes me think there's something wrong with my setup for this. I have a small LED panel that i placed on the end of the scope and let the ASIAIR do its auto exposure for flats but the results have a distinct gradation down both sides.

But this is nothing to do with the AZ-GTI so i might post something on the Beginning Imaging section.

[Elp]

It does look odd, if there's any vignetting one would expect it in a circular pattern around the edges of the image. I assume that the LED panel is fully covering the whole aperture of the telescope and it is an evenly lit panel? The way I then take flats with the asiair is to use preview mode and alter the exposure time and take one photo and once it uploads to my phone I check the histogram peak is around halfway across the graph, once I'm happy with the histogram i then put this exposure time into a plan and run off around 30-50 of them at once.

[RayWUK]

Yes, that's what i thought, the LED panel well covers the scope and using the auto flats exposure on the ASIAIR gives a histogram peak at the halfway point on the graph (32000).

The other thing is the level of the bias frame at around 8200 (0.001sec exposure) which seems high to me, but i don't know if i should be expecting anything lower.

[Elp]

Visually your bias frames should look similar to your darks. Your screenshot above looks more like a flat to me. Are you taking the bias the same way as a dark? (Cap on end of telescope, shortest exposure).

[RayWUK]

2 hours ago, Elp said:

Visually your bias frames should look similar to your darks. Your screenshot above looks more like a flat to me. Are you taking the bias the same way as a dark? (Cap on end of telescope, shortest exposure).

Yes the above frame is a bias frame with the lens cap on @0.001 sec.

Below is a dark frame @120secs.