Guiding Issues - ASIAIR

[xa-coupe]

I've been doing this for a few years now and for the most I've managed to get acceptable guiding, through using software like APT and NINA interfacing with PHD2, and it got even better when I got an ASIAIR. I was able to get 10 minute exposures but generally ran 180-300 seconds for my data collection and got well under one arc second, sometimes down to .2 for most of the night.

Recently (last few months) it's been squirrely and out of nowhere I get a major spike which obviously ruins that particular image. I've checked cables for snags and made sure my balancing is correct and all alignment knobs are tight (from experience!) yet it is still doing it. I forced a recalibration just in case.

Using: ASIAIR
William Optics 32mm Uniguide scope
ZWO120MM mini 3s exposures, default gain
Saxon NEQ6.
Power is supplied from a 12v power adapter.

One 'interesting thing is I aligned the rig last night, did some imaging and had it turn itself off. When I fired it up tonight I had to re-polar align it even though there had been no changes.

I'm hardly an expert but I'm also not a beginner and I've run out of ideas. Googling hasn't netted any usable results.

I'd rather not go back to a computer because a) I paid for the Asiair and it has worked well before, and b) the computer I previously used has lunched itself.

I'm at a bit of a loss and am after suggestions for things to look at.

thanks

[AdamJL]

To get the obvious question out of the way, but you're locking the azimuth bolts, right? And everything is screwed down perfectly? If you're losing polar alignment, sometimes that's down to something not being locked correctly.

[xa-coupe]

Absolutely I did. I've caught myself out on that one before today. I'm not as sold on the Asiair PA as PHD2 even though I believe it's based on PHD2.

[ronson]

How is the power feed done? A good practice is to power the mount separately from Asiair and not power the mount via Asiair.

Also, if the whole setup is directly connected to a wall outlet and if you want to exclude any power fluctuation, use a battery powered station, even a UPS.

For PA, there is a setting in Asiair to remember it, so you don't have to do it each time your start it.

The spike can be caused by many things incl weather, guiding app issue, guiding equipment issues, mechanical issues with the mount etc. You haven't mentioned what scope is the above setup used with. Also, best to post an example image with the issue. Might help the troubleshooting.

[xa-coupe]

That's a good point. I power the mount from the ASIAIR though I power the dew heaters separately, I'll try that.


I do have a battery that's suitable, I'll give it a go.


I usually do that but out of curiosity I occasionally redo it after not moving to see what happens. There's always enough of a difference I have to adjust it.



It's a small WO GT81 on an NEQ6 so it's well within the weight limit. No winter in Melbourne is without the wind but it's in a protected back yard so I wouldn't expect it to be too much. I also tend to delete the rubbish images as I go along but I'll save one as well as a screen shot of the guiding at the time.

Thanks for your assistance!

[Startrek]

For these spurious events I like to go back to basics as a base line ……,
Re balance rig in Dec and Ra
Check your polar alignment first ( a few arc min is fine with PHD2 )

Launch PHD2 direct to mount ( not via the ASIair or your acquisition software like APT
Run through the installation wizard to ensure guide camera and settings are correct, including creating a dark library.
Run the calibration assistant to get a good calibration at Dec=0
Try the PPEC algorithm instead of Hysterisis ( I haven’t use Hysteresis in 5 years , always use the PHD2 PPEC algorithm.
Pick an object above 40 deg Alt and guide for 20 mins long enough to let PHD2 record a few worm cycles
See how it performs ?

By the way was your big spike in Ra or Dec ?

It may very well be a millisecond signal interruption to a pulse running PHD2 via other programs

Also could be Stiction on your worm or main thrust bearing ( old grease with a bit of crap in the mix )

Obviously not a cable snag ?

Obviously not a wind gust ?

These events are always a pain in butt but it’s best to start from the beginning and run the basics direct to the mount ( when it comes to PHD2 guiding )

Good luck
Martin

[xa-coupe]

Thanks Martin.

I did figure out what was causing it by going back (in my mind) to when it worked well at the old place.

I went outside and watched it whilst the guiding was going nuts with my very light dew 'blanket' blowing around. Surely, I thought, it is too light to do anything and particularly as it wasn't going anywhere near the objectives ... but I took it off and Viola!! fixed... embarrassing but nonetheless, it is guiding very well.

I'm going to have to accept a limited life for the Asiair or find another way to shield it from the dew. As for tonight and this week, it gets it all.

Thanks to all for the ideas, it was by eliminating everything else that I came to the conclusion that fixed it.

[SB]

Hi Jeff,
Glad you found the solution, I had a Frogmouth Owl keep landing on my scope that caused my guide spike!

I’ve never used dew protection for the ASIAIR as it tends to get warm enough so the dew doesn’t settle on it.

Chris

[JA]

Hi Jeff,

Regarding a dew cover for the Asiair....

Perhaps you could fashion a neoprene (wet suit type material) case/cover for the Asiair with the required holes for cables/etc locked to itself with Velcro or form fitted somehow. Maybe even experiment with a hacked up stubby holder, or look for something similar on eBay to hold something roughly the size of a pack of cigarettes.

Best
JA

[Nikolas]

No need for a dew cover on the asiair as it gets warm enough to not dew up last 2 nights were frosty in my backyard and I left it running all night no dew issues I turned it off in the daylight. I just set it to go to home position but leave it on after a sequence

[xa-coupe]

Thanks, maybe, as Nik says, I should just leave it running instead of auto shut off.
As it turns out, there wasn't a lot of dew, probably because of the wind.

[ronson]

Glad you managed to figure out the issue and it turned to be an easy fix.

As the others have said, there is no need for a dew cover for the Asiair as it gets warm enough to keep the dew away.

However I would recommend to 'seal' the unused ports, especially the Ethernet port to avoid moisture or dirt build up which could cause issues in the long run. There are dust plugs you can get for Ethernet, USB and other ports from eBay and the likes.

[xa-coupe]

good idea, I have a few RJ45s around and I can fill in the spare USBs with sticks for more storage.

[Startrek]

Ive been using black Electrical PVC tape on all spare un used USB and RJ ports on Mount, Hubs and Lappy for years
Cheap and effective
I’ve only changed them twice in 3 or 4 years when the tape dries out.

Cheers
Martin

[xa-coupe]

Thanks Martin. I might also change to a losmandy rail which will give me some real estate to mount the unit underneath it for additional protection, assuming the cables will reach of course.

[Startrek]

Yeh I use a Losmandy 14” dove tail plate for my 8” Carbon newt in Sydney and it allows me to mount my Startech industrial 4 port powered Hub to the underside plus the plate acts as a really neat conduit cabling path to the focuser for camera cabling, EAF cabling and EFW cabling.
In my Dome south coast NSW with the 10” Carbon newt I use a longer 17” Losmandy dovetail bar which performs the same function.
Obviously with medium to large Newts you need a heavy duty long dovetail bar and utilise it for various cabling and equipment requirements.

Cheers
Martin