ASIAir / AM5 guiding results

[david_taurus83]

As already mentioned in a previous thread, I have long held the belief that the ASIAir shows somewhat optimistic guiding results. I am a newcomer to the ASIAir when I first purchased one (Mini) when it was released around this time last year. It went hand in hand with the AM5 mount that I also purchased around the same time. It made an attractive proposal for a small, lightweight but very competent setup for my Redcat but with the opportunity to also put larger scopes on there if I fancied a change. I was surprised with the AM5's reported guiding figures as reported by the Mini. Typically it would show an average of 0.4 / 0.5" RMS with occasional dips into the 0.3" range. Very impressive considering I only use a small 30mm f4 guide scope with a pixel scale of 6.5" per pixel, though I did take with a pinch of salt.

Recently I decided I was going to swap over the AM5 onto my pier. Out came the AZEQ6 which guides at a typical 0.6" /0.7" RMS which is the norm for the EQ6 range. I have had better guiding when the seeing permits but it tends to be for shorter spells and the average is usually the typical. Yesterday I mounted up the AM5 using my homemade pier extension and we happened to have a few hours clear spell in the evening. 

 

After polar aligning and calibrating in PHD i ran a guiding assistant. It shows a peak to peak PE of around 30" over 7 minutes. Similar to the SW though thats over 10 minutes I believe. I wonder if there is need for short duration guiding at all looking at the PE curve. 

I left the mount guiding away for about an hour anyway on 1 second exposures to record its first session. The seeing probably wasnt great last night but the mount still managed a fairly run of the mill average of 0.8"RMS. Not too bad but certainly nowhere near as low as 0.4" at any point. Will be interesting to see how it performs if i try 2 or 3 second exposures. I will also look to use my AZEQ6 with the ASIAir to see how that reports its guiding. If im right it will be an improvement over the norm.

[knobby]

I run my HEM 27 at 0.75 seconds, many people suggest short guide exposures due to the PE on strainwave mounts. I have tried 1, 2 and 3 seconds just to see for myself and although not much difference I stuck with fast guide exposures to 'conform' 🙂

What I did find helped was PPEC in PHD2, I can see a definite improvement usually after about 10 minutes.

I do only get down to about 0.7" though but I think that's just my poor local seeing. 

I guess it's in ZWOs interest to 'tweak' the output of PHD2 on the Asiair, It's a bit like having your Mum being the judge of your own court case 😂 so I can see where you're coming from.

ps  - that must be the strongest coffee tin I've ever seen !

 

[Elp]

My hem also responded to 0.5s exposures but I left it around 1s. It didn't really like 2s which I usually use with my azgti and gem28. Subs were fine in either case though regardless of the RMS graph and figures.

Edited October 30, 2023 by Elp

[david_taurus83]

8 hours ago, knobby said:

 

ps  - that must be the strongest coffee tin I've ever seen !

 

Lol its full of concrete! I just couldn't stomach the £200 or whatever it was for the ZWO extension. Might sound a bit daft considering how much I paid for the mount and camera last year but I promised myself I was done with astronomy purchases this year. 

[david_taurus83]

Another test a couple of nights ago. Same as the first night, an average of around 0.8"RMS. It was OK before a meridian flip but later in the night there are large deviations. I am hoping it was due to passing cloud but as it was unattended I can't be sure. The weather hasn't justified setting the AZEQ6 up to see what the Air reports on that.

 

[david_taurus83]

Another few rounds with the AM5 on the pier and guided via regular PHD2. 

Typical guiding rates of around 0.8"RMS throughout the sessions. I tried both Hysterisis and the PHD PPEC algorithms with not much difference between them both. It certainly never got down to the 0.4" levels usually reported the the ASIAir graphs. I think it's safe to say that my original suspicions of the Air figures are correct, at the very least the in app graph is wildly optimistic. This is not to say the AM5 is a bad mount, it's not, it's definitely up there with performance levels of a SW EQ6 class mount. More than adequate for most of us hobby folk though it prob is limited to focal lengths of less than 1000mm, which is in fact what ZWO recommend.

I did also manage a couple of sessions with the AZEQ6 and ASIAir Mini. I have my Redcat on there at the moment and it does look a bit silly on the AZEQ6 so I will be swapping it back onto the pier next weekend weather permitting. The guiding logs show what I would consider decent guiding for a SW mount even with an OAG but considering I have a 30mm F4 mini guidescope on there so with a pixel scale of 6.45" per pixel I think the typical 0.6"RMS in the logs is also a bit suspect. What I find strange is the logs on the Air report that corrections aren't issued with every exposure whereas on regular PHD on the pier corrections are issued with every exposure so I wonder if this is a factor in the overall RMS score for the Air logs. Both setups are set to 0.1" min move BTW.

The nail in the coffin for the Air graphs in my opinion though is this screenshot I took on Friday evening after I setup the AZEQ6. With 1s exposures as well.

Yeah right!