Guiding a Star Adventurer - how successful have you been?

[Dezerker]

Hello everyone!

How well do people manage guiding with a Star Adventurer?  I'm struggling - the RMS error lines for RA are a roller-coaster no-one would want to go on!  Is there a way of calculating how much guiding error I can get away with at different focal lengths before it starts impacting my frames?  I'm hoping to image at longer focal lengths with this setup soon...

I'm getting distinctly average (though not exactly crisp) frames imaging with a Canon 6d at 85mm, controlled by an original ASIair.

Background info:

It's a reasonably well balanced set up (in that neither the camera nor counter-weight end drops when the Star Adventurer clutch is loosened) and I've followed the polar-alignment routine down to 0.5" or less on RA and DEC, so that can't be too far off.

I think the Dec line shows the polar alignment isn't too hideous...although it does sometimes wander off a bit as you can see.  Any idea what causes that?

Graph from windless nights, firm ground away from vibrations etc, and is pretty typical regardless of the pulse duration, guiding interval of aggression setting I use...

Any thoughts, comparisons, suggestions etc?

[Chefgage]

My RA error is usually around the 2" mark.  Have a play with the RA Aggr setting. I sometimes up mine to say 90%. There is then a bit of a delay for the changes to take effect but it usually then brings down the RA error. That's about as good as I have got it. It sometimes goes down to about 1.8" error. 

I just put it down to the star adventurer not tracking in DEC and being a small mount.

I have been getting 3 minute subs with a 72 ed refractor at 420mm focal length which I don't think is too bad.

[Chefgage]

For some reason I was struggling to get the RA down to 2" (where it normally guides at) the other night. I seemed to stay around the 3 to 4" mark. As the OP asked I would also like to hear from others guiding with the star adventurer as to what error values they are getting when guiding.

[Chefgage]

On 13/03/2021 at 17:21, Dezerker said:

Hello everyone!

How well do people manage guiding with a Star Adventurer?  I'm struggling - the RMS error lines for RA are a roller-coaster no-one would want to go on!  Is there a way of calculating how much guiding error I can get away with at different focal lengths before it starts impacting my frames?  I'm hoping to image at longer focal lengths with this setup soon...

I'm getting distinctly average (though not exactly crisp) frames imaging with a Canon 6d at 85mm, controlled by an original ASIair.

Background info:

It's a reasonably well balanced set up (in that neither the camera nor counter-weight end drops when the Star Adventurer clutch is loosened) and I've followed the polar-alignment routine down to 0.5" or less on RA and DEC, so that can't be too far off.

I think the Dec line shows the polar alignment isn't too hideous...although it does sometimes wander off a bit as you can see.  Any idea what causes that?

Graph from windless nights, firm ground away from vibrations etc, and is pretty typical regardless of the pulse duration, guiding interval of aggression setting I use...

Any thoughts, comparisons, suggestions etc?

Forgot about this post. Are you still having problems? Are you using an asiair pro or a laptop. I ask as there appears to be issues with the asiair when guiding.

[Chefgage]

On 13/03/2021 at 17:21, Dezerker said:

Hello everyone!

How well do people manage guiding with a Star Adventurer?  I'm struggling - the RMS error lines for RA are a roller-coaster no-one would want to go on!  Is there a way of calculating how much guiding error I can get away with at different focal lengths before it starts impacting my frames?  I'm hoping to image at longer focal lengths with this setup soon...

I'm getting distinctly average (though not exactly crisp) frames imaging with a Canon 6d at 85mm, controlled by an original ASIair.

Background info:

It's a reasonably well balanced set up (in that neither the camera nor counter-weight end drops when the Star Adventurer clutch is loosened) and I've followed the polar-alignment routine down to 0.5" or less on RA and DEC, so that can't be too far off.

I think the Dec line shows the polar alignment isn't too hideous...although it does sometimes wander off a bit as you can see.  Any idea what causes that?

Graph from windless nights, firm ground away from vibrations etc, and is pretty typical regardless of the pulse duration, guiding interval of aggression setting I use...

Any thoughts, comparisons, suggestions etc?

Having had a bit of a play around with the settings last night I got my RA down to 1.5" from never really going below 3". Instead of the exposure setting being 2s I changed it to 1s and then 0.5s. This brought the RA error down to 1.5". Although I assume you need good seeing as there was not many available guide stars at 0.5s.

[Dezerker]

Hey @Chefgage, sorry for the slow reply (crazy time at work) and many thanks for your thoughts on this - yeah there's definitely some nights that are better than others - I struggle with the inconsistency but guess that seeing, high level clouds etc might have an impact?

I'm using the ASIair - the orginal (white) one.  It's great when it works well, it's a pain in the backside when it doesn't!  I'm wondering if it's an ASIair power issue, mine is regularly throwing up the low voltage warning, despite the power pack I'm using for it being comfortably over what it requires...and I guess that would impact on the signals that it's sending to the Star Adventurer to guide?

Getting it down to 1.5 is epic with the Star Adventurer, nicely done!  I haven't come close to that yet - I think about 2.5 is my best in RA.  I'm surprised too by how much DEC seems to bounce around / disappear off on it's own for a while, even though I've got that switched off.  It sometimes comes back a few minutes later - it literally seems to have a mind of its own.  I get that it would gradually drift off if my polar alignment was out, but can't figure out how it can suddenly just wander off by 4-6' stay there for 5 minutes then trundle back.

On RA aggression, I've been trying higher and lower settings.  Both seem to have their merits.  Higher makes adjustments quicker if it's going off track, but it almost then seems to be triggering and over-correction for me.  Definitely need more practice. 

And of course it seems like any adjustments to any part of the rig, balancing it, moving the camera / guider to the target object, changing a battery, even focusing the camera, almost inevitably knocks your PA - I'm hoping for some good results soon.  The frustration is such that I'd almost rather spend more and stick everything on a bigger, sturdier mount, despite the cost, but I really need the portability with this set up, so have to make it work!

[Chefgage]

18 hours ago, Dezerker said:

Hey @Chefgage, sorry for the slow reply (crazy time at work) and many thanks for your thoughts on this - yeah there's definitely some nights that are better than others - I struggle with the inconsistency but guess that seeing, high level clouds etc might have an impact?

I'm using the ASIair - the orginal (white) one.  It's great when it works well, it's a pain in the backside when it doesn't!  I'm wondering if it's an ASIair power issue, mine is regularly throwing up the low voltage warning, despite the power pack I'm using for it being comfortably over what it requires...and I guess that would impact on the signals that it's sending to the Star Adventurer to guide?

Getting it down to 1.5 is epic with the Star Adventurer, nicely done!  I haven't come close to that yet - I think about 2.5 is my best in RA.  I'm surprised too by how much DEC seems to bounce around / disappear off on it's own for a while, even though I've got that switched off.  It sometimes comes back a few minutes later - it literally seems to have a mind of its own.  I get that it would gradually drift off if my polar alignment was out, but can't figure out how it can suddenly just wander off by 4-6' stay there for 5 minutes then trundle back.

On RA aggression, I've been trying higher and lower settings.  Both seem to have their merits.  Higher makes adjustments quicker if it's going off track, but it almost then seems to be triggering and over-correction for me.  Definitely need more practice. 

And of course it seems like any adjustments to any part of the rig, balancing it, moving the camera / guider to the target object, changing a battery, even focusing the camera, almost inevitably knocks your PA - I'm hoping for some good results soon.  The frustration is such that I'd almost rather spend more and stick everything on a bigger, sturdier mount, despite the cost, but I really need the portability with this set up, so have to make it work!

Although I am now happy that is have got my RA error down to 1.5 ( goes down to 1.2 on occasions) I now seem to be having a problem with exposure length. I have been able to get 300 second exposures with 420mm focal length (72ed refractor) but for the last two sessions I have only managed 105 second exposures before star trails happen. This coincides with the decreased RA error. I can't think that by improving my RA error that has decreased the exposure time?  I can obviously experiment with this by changing the guiding exposure back to 2 seconds and seeing if this brings my exposure time back to 300 seconds. Seems a bit weird.

I have also thought about a sturdier mount, so much so that I bought one. I have gone for a HEQ5 pro and will put all my existing equipment on that. But I too want the portability so I can see a few more purchases coming so that I have two setups (been waiting 9 weeks now for the delivery of the HEQ5, probably be a lot longer yet).

[trailer]

This is with the SA2 guiding through PHD2 / EKOS / KStars. First time with dithering and the PHD2 multi star option ticked. Able to get 300s shots with no trailing through a WO Redcat51, WO wedge and a Manfrotto 190GO tripod. Polar Alignment was done with a Polemaster. I think a better quality tripod might help smooth things out a bit.

[iapa]

Things that come to mind.

do you have the Star Adventurer Pro - I expect you do if you have the ED72 on it.

get nice sharp focus with the guide scope, then back it off a little bit to blur the stars a bit - PHD likes stars that are not too sharp for it centroid calculations

Turn off guiding in DEC, it’s not going to happen

power to until separately, e.g. not through the ASIAir - even just a splitter to feed the ASIAir and mount independent of each other

how is your balance on DEC, make it a little from heavy.

Guiding is affected by seeing as it changes the stars

 

and please see my signature

Edited April 13, 2021 by iapa

[iapa]

A quick check on weights and you are running in the region of 85% of the mount payload.

[iapa]

4 hours ago, iapa said:

how is your balance on DEC, make it a little from heavy.

 

That should read ‘front heavy’

[Dezerker]

On 09/04/2021 at 08:54, Chefgage said:

I can't think that by improving my RA error that has decreased the exposure time?  I can obviously experiment with this by changing the guiding exposure back to 2 seconds and seeing if this brings my exposure time back to 300 seconds. Seems a bit weird.

I have also thought about a sturdier mount, so much so that I bought one. I have gone for a HEQ5 pro and will put all my existing equipment on that. But I too want the portability so I can see a few more purchases coming so that I have two setups (been waiting 9 weeks now for the delivery of the HEQ5, probably be a lot longer yet).

That is weird - I have wondered about going with a faster guiding exposure time, and plan to trial next time we have clear skies - be interested in what happens if you do change yours back.  The pattern I see all too often with 3 second exposures is a correction sent to the mount when it was maybe 1" out, that sends the mount so far out the opposite way that 3 seconds later when it next looks, it's already too far gone!  This then triggers 3 correction pulses, the first halts that direction of travel, the second correction pulse brings it some of the way back, and once again, the third correction completely overshoots.  Repeat until all hair is torn out!

But I've heard that shorter intervals can mean you're "chasing the seeing", so presumably as the guide star appears to distort, the guiding software reads that as a movement, and sends a pulse to the mount to follow it...I don't know whether that could be worse than what I have now, so I'll try it!

Good shout on the HEQ5 - my friend uses one with a 400mm lens and a stock 50mm finder guider, and it seems so much more consistent - regularly gets total RMS of 1 or below.  I'm very tempted...that said, I actually borrowed just his HEQ5 tripod legs and put the Star Adventurer on that - significant improvement!  I've been wondering if there was a mount between the Star Adventurer and the HEQ5, but I guess it's stability vs portability for now.

Does anyone know if there is a way of getting PHD, ASIairs etc to track and show you the graph without sending any guiding pulses?  I'm curious to know what the tracking is like with and without guiding. 

[iapa]

PHD2 guiding assistant, under tools

[Dezerker]

1 hour ago, iapa said:

PHD2 guiding assistant, under tools

Thanks, I'll have a look!

[GDN]

Just to add my little bit of experience with  my  Star Adventurer.

 

I have had mine for a while, and I really didn't get on with it when I first brought it. So it got put away, for a few years. I have dug it out again, as I have a little more spare time now, and I found that when I rotated the mounting bracket with the clutch loosened off, there was a tight spot. I loosened off the small hex nut under the clutch, and it seems to be ok.

I brought myself a guide scope and camera, along with a years license with Sharpcap Pro, and off I went. Again.

With excellent polar alignment with Sharpcap, I am getting 2.5" to 3" in RA. This is using a 2.5 sec shutter. I am playing around out on the back garden before I go out into the wild away from the city to have a serious try at imaging. but what I have found by trying different things is that the error in RA can be lowered.

The tripod that I am using has spikes on the end of the feet. If I push them into the ground carefully with my heal it feels very solid. The tripod is a hand me down heavy video type.

Today, I aligned the polar scope and the guide camera on a mobile phone tower that is I guess 500 meters away during the day. Tonight, I tried again. I also found for me that 0.5 sec works best. I was able to get my error in RA down to 0.98". I tried this numerous times, and I kept on getting a similar result. Then the clouds rolled in, and that was the end of that.

I want to try a few more different things with the gear that I have, and see if I can lower the RA error even more.

I'll let you know how I get on.

Gary

[Dezerker]

On 17/04/2021 at 13:24, GDN said:

Just to add my little bit of experience with  my  Star Adventurer....

That's really interesting, thanks Gary.  Particularly pondering that tight spot you mentioned.  It feels like my Star Adventurer is sort of 'sticky' - even when the clutch is loosened right off, it feels like there's spots of resistance when you then try to rotate the mount through RA.  Like you, I'm trying to hone my setup and get as much experience as I can, so that I can take it out to darker skies and have it really perform the way I hope it can.

Interesting too to hear your better results with shorter guiding exposures - clear skies (and weekend of course) here tonight so might give that a try, despite the blinding great moon in the sky!

Thanks again - look forward to hearing how you get on.

[GDN]

19 hours ago, Dezerker said:

That's really interesting, thanks Gary.  Particularly pondering that tight spot you mentioned.  It feels like my Star Adventurer is sort of 'sticky' - even when the clutch is loosened right off, it feels like there's spots of resistance when you then try to rotate the mount through RA.

I brought my one about 5 years ago when I lived in Darwin, Australia. Darwin is something along the lines of 14° south. When I looked through the polar scope to find Octans, I found all that I could see was trees.  Hence one of the reasons I put it to one side. But when I was using it then, the mounting bracket would rotate freely without any tight spots.

Fast forward onto now, we have moved cities. I have dug out the tracker, and I found that when the clutch was loosened off, there was one area where when you rotated the mounting bracket, you would need a little more pressure to move the bracket past this point. Once past it, it was smooth again until you rotated it to the same place. I am not talking about needing both hands to rotate it, I just needed a little more effort. I did think that it was not like this when I was in Darwin. Plus the thought of would this impact the trackers accuracy.  My thinking then went to stripping the mount down and replacing the grease in it. But when I started to research on how to do this, I came across someone who had the sticking mount problem, and he just loosened the hex nut. That is the route I took. My mount now turns freely. I think you want a 3mm hex key.

If think it is worth giving it a try first if you are having this problem. I never done any testing to see if it has had any impact on my results, as it was the first thing that I looked at once I got my tracker out again and got it going. I would be interested to see if it has any impact on your tracking accuracy if you slacken off this screw.

19 hours ago, Dezerker said:

clear skies (and weekend of course) here tonight so might give that a try, despite the blinding great moon in the sky!

I would happily put up with the moon and go out and experiment a little more, for no clouds.

Gary

[Chefgage]

My guiding seems to be getting slightly better each session. Last night it was going between 0.9" and 1.5". With the star adventurer balancing in RA is quite easy (depending on the payload combination) but not so easy in DEC I have found. But certainly the better overall balance that is achieved helps lower that RA error.

Edited May 7, 2021 by Chefgage