Settings for AsiAir Plus Guiding: Page 4

Settings for AsiAir Plus Guiding

w7ay

Ernesto221 I tried to move the scope up-down, in every position but this message is always shown.

I assume this question is addressed to me?

When you calibrate, the best place is to choose a Right Ascension (RA) that will place your OTA near the Meridian (but not right at the Meridian since it might interfere with Meridian limits of the mount, etc). An hour away is pretty good, that way you are then 15º away from the Meridian.

For the declination (this is what your screenshot is complaining about), choose a number close to the celelestial equator. As the screenshot shows, you are recommended to point to between declination -30º and declination +30º, i.e., within 30 degrees of the equator.

If you try to calibrate close to the pole, the problem is that the sky would hardly move in the hour angle direction. If you calibrate right at the pole, for example, the RA nudges would not even move where the telescope is pointing at (it simply changes the camera angle). And you'd end up with PHD2 complaining that your mount did not move enough.

It is actually not too bad to calibrate at +60º and autoguide right there, as long as you don't try to use the same calibration to autoguide a target that is near the equator. If you calibrate near the equator, that calibration is good everywhere (has to do with a correction factor, whose error is large when you do it the other way), do it once for the night near the equator, and you are good for the rest of the night (just need to remember to flip the calibration after a Meridian Flip).

As to calibrating near the Meridian; that is to get as far away from atmospheric refraction as you can.

I highly recommend reading the documents at the openphdguiding.org web site before turning on and using the ASIAIR. You learn nothing by using the ASIAIR.

Chen

Ernesto221

Many thanks Chen for your deep instructions, but I get already such info reading some treat on this forum. I wrote you beacuse this message appear at the beginning of guide calibration and always indipendently of the position of OTA.
I tried to point the telescope at 30° - 60° - 90° rotating ecc..... non way to proceed on calibration without tap GO ON to skip this message advise.

tbhausen

Ernesto221 I saw the same error message you're seeing until I did a successful go-to immediately after polar aligning (this initiates tracking), then send the scope to home position, then go-to a target near celestial equator (but not near meridian, as Chen helpfully noted). Once that second target was centered, I was able to calibrate and initiate guiding. Not an educational answer, but that worked for me and my guiding is almost always under 1.5", and I've gotten nice, round stars with subs as long as 5 minutes with the SA GTi.

Chen, I apologize for jumping in and answering the question that was directed to you (I didn't notice). I imagined Ernesto standing at his scope trying to get a "quick and dirty" answer to get past a dialog box I'd recently encountered. I appreciate how much effort you put forth helping others here, and your detailed explanations. Speaking for myself as a beginner, I came here "just wanting things to work", but with eyes and ears wide open to learn as I go. I've learned more here and on cloudynights in the last couple weeks than I did back in the day before my aging vision stole away my ability to fully enjoy visual astronomy.

w7ay

tbhausen I've learned more here and on cloudynights in the last couple weeks than I did back in the day before my aging vision stole away my ability to fully enjoy visual astronomy.

You are not alone. I am in my 70s, and has undergone cataract surgeries on both eyes.

Back when I started astronomy back when I was a teenager, I could actually count 7 stars in the Pleiades even though I was already wearing eye glasses. I finally gave up visual astronomy altogether back when I was in my 50s and went to DSLR and Starlight Xpress CCD cameras. Nowadays, I only take out my eyepieces when I do collimations :-).

Chen

Ernesto221

tbhausen

tbhausen
Hello TB, I really apreciated any suggestions on this issue that can help me to set ASIAIR and my actual setup.
I let you know the result asap. Unfortuntaly today is raining in Milano and coming nights seems not to be clear.
A part this issue on ASIAIR alert message, may I have have some indications about Autoguide setting values condìsidering my actual stup ?
Main Scope : Heyford 80mm/550- f6,25, ASI294MC Pro
Guide Scope : 60mm/228-f3,8 ASI-224MC
Mount : HEQ-5Pro EQMode connected to ASIAIR
There are so many discussions and treat describing how to define auguide values like :
Calibration Step
Max DEC Duration
Max RA Duration
Dither Setting

Best Regards

tbhausen

w7ay I was born prematurely, which screwed up my retinas... I'm not complaining, though! Many were less lucky during that time (early '60's). It's a great time to be interested in astronomy, good vision or not. From JWST to what we can assemble here, there's much to learn and enjoy!

tbhausen

I’ve only had one night of guided imaging myself (due to weather). So I haven’t gotten to experiment to optimize guiding settings at all. I left the guiding rate at 0.5 and set both aggressiveness values to 75%, that’s what I remember until I get home to review the settings. I’m sure others here can be much more helpful.

chaitanyakhoje

Hello everyone, I am new to this forum and need some help in understanding phd2 logs generated by ASIAir and how to make necessary adjustments, I once posted in one of the thread where people were calculating durations according to their PE graphs for AM5, after wandering that thread, I am here to understanding guide settings first.
So this is my current equipment:

Mount: AM5
Imaging camera: ASI294mm Pro
Telescope: Redcat 51 II
Guide camera: ASI220mm mini
Controller: ASIAir Plus
Focuser: ZWO EAF
Filter wheel: EFW w/ narrowband filters

When I started with this mount, I had the ASI120mm mini as the guide camera and I am seeing an improvement in RMS when I upgraded to the 220mm mini.
I live in Bortle 8-9 area and use narrowband filters for imaging.
I calibrated the guiding near the celestial equator (on the star Altair), but I don't have a good view for declination, I have heard that you should calibrate guiding near the intersection of Meridian and Celestial Equator? Please correct me if I am wrong, here to learn!
Ok so coming to the problem I'm facing, with the new guide camera I saw a drastic improvement in the RMS, around 0.4", I've also seen 0.3" at times which I really didn't expect, but then after some time, the guide star drifts away.
I probably might be using the guide camera FL incorrectly as well, I set it to 200 and I think it should be 1/3-1/4 of the main imaging telescope.
I have attached 2 screenshots as well, the drift in those is not visible that much, but at RA and DEC Aggr at 30%, the star drifts towards right top (or reticle drifts bottom left) gradually very slowly, I think these details are there in the log but that's what I remember from the session.
I want this to be my lack of knowledge and not the mount itself. I haven't actually tried Phd2 yet for guiding but that's the next thing, and I am currently going thru the docs. I believe Guiding Assistant from Phd2 might help as well. I'll also try using the drift alignment to see if I have PA issues.
I also did the Polar alignment 3 times, just to be sure, for the first two times I noticed the error re-appeared, and looked like I tighten the knobs way too much. So for the 3rd attempt I just tightened them as needed.

Edit:
After I see the star drifting from the guide square, I see a lot of star trails in the images (not particularly in the same direction), one of which looks like the following;

autorun-log-2023-06-15-233346.txt

16kB

phd2-guidelog-2023-06-15-230659.txt

906kB

Kevin_A

chaitanyakhoje what guide scope are you using or are you using a OAG?

chaitanyakhoje

I’m not using OAG, just a normal guide scope from svbony. Here’s how my setup looks, I’ll probably invest in some smaller wiring.

Kevin_A

chaitanyakhoje ok so your focal length for the guide scope is 120mm and your calibration step size will be around 2000ms. You need to input this in asiair. I have the same guide scope on my small fast rig but i added a fune tune focuser to it.

Prusling

Sorry a little off topic but where did you get those cable tidies from?

chaitanyakhoje

Prusling look for “Smartcomponents” on Etsy for those cable organizers.

Kevin_A nice clean setup you have there! Alright I can try those settings tonight, thanks!

chaitanyakhoje

Kevin_A ok so I tried those settings, but they didn’t quite work much for me, still saw an uncertainty in the RMS overtime as before. I switched to calibration 1800, RA and DEC at 1000, guide FL at 220mm and saw a significant improvement in guiding, calibrated at the same target as before on the Altair star.
I think all this depends on our visibility, location, number of guide stars, and mainly the calibration target.
I’m seeing RMS < 0.5 and I saw 0.25 tonight which I thought was not possible for my AM5.
Although this time I chose a simpler (probably) target - NGC 7635 (bubble nebula).

ckoos

I found guiding to be the most frustrating and non-intuitive aspect of this hobby when I started a couple of years ago. At one point I started searching on Amazon for a baseball bat, which I was going to use to show the equipment who was ultimately in charge. Luckily I didn't follow through with the purchase.

My opinion is that setting aggression to 30 is going to cause problems, assuming that the AM5 doesn't have specific requirements in this area. That setting means that after PHD2 calculates the correction needed to keep the guide star centered, you only send 30% of that pulse to the mount. I would think that would lead to the guide star eventually drifting out of the lock zone.

Bruce Waddington, one of the PHD2 developers for the last 11 years recommends always leaving aggression to default. Here's some links to videos where Bruce and Andy (the other PHD2 developer) do a really good job of explaining PHD2.
https://www.youtube.com/watch?v=ifbLY6Q-cN8
https://www.youtube.com/watch?v=LbhxX7PH2CE
https://www.youtube.com/watch?v=LXFGRta98rs
https://www.youtube.com/watch?v=ty8hukjAPMw

Keep in mind that the the guiding tool in ASIair isn't pure PHD2. The engineers at ZWO copied the PHD2 source code, did stuff to it, then added it to the ASIair. This is why the PHD2 developers won't support questions about guiding with an ASIair, they don't know what changes ZWO made.

-chuck-

Kevin_A

chaitanyakhoje please be aware that if you use a 120mm guide scope and put in 220mm the guide numbers will be better but your guiding will not be! It gives you false numbers. I did that once and thought that my guide numbers were awesome…. Until i realized i had doubled my guide scope fl.

Kevin_A

chaitanyakhoje with a guide scope like the svbony and big pixels like with the 220 camera 0.5rms is very good. The guide scope is not great and has a small apeture. I used mine last night and averaged 0.5rms all night long and had blips here and there but all round stars. Dont get hung up on numbers or put in random fl numbers… it is a 120mm guide scope and 0.5 is excellent for such an amateur grade mount.

chaitanyakhoje

Kevin_A I see, yea you’re right the FL was giving me good guiding numbers but still had to discard some frames. Yesterday I switched back to 120 and this time 0.5 instead of 1 and the guiding numbers didn’t look that good but got some 5 min frames with round stars. Some of them still had streaked stars but it might be mechanical or most probably the calibration. This is how my calibration graph looks like; the lines look perpendicular but are tilted, can you guide me on what this means, or how does it compare with your calibration?
Edit: I live in a bortle 8/9 and 0.5 is sometimes crappy for me, but it has definitely improved over the 120mm even on 0.5

chaitanyakhoje

Kevin_A thank you for your suggestions! The settings you mentioned worked pretty good for my guide setup, after some minor changes on the RA and DEC durations. Yesterday I got really good guiding and just had to discard 2-3 frames out of 50 (5min exposures).
Only thing is that my setup isn’t fixed and I probably have to recalibrate every session, which is fine.
I guess adding some weight to the tripod and redoing PA just to ensure accuracy also has helped me for yesterday’s session.

w7ay

chaitanyakhoje the lines look perpendicular but are tilted

Simply means that your guide camera angle is not aligned to the RA-declination axes. PHD2 uses a transformation matrix to correct for this, so you need not do anything about it.

If you really want the red and blue lines (declination and RA units) to be parallel to the camera axes, just rotate the camera and watching the camera angle in the plate solves.

You will notice that calibrating nearer to the pole will create a non-orthogonal calibration (accute angle between red and blue lines), which potentially makes this correction more error prone (division by numbers that are too close to zero) when you try to guide stars closer to the equator. This is the reason to always calibrate near to the celestial equator -- the error is small enough if you are within 30º of the equator, so you need not be too anal about it.

"Guide calibration" is simply a process of measuring the camera pixels units (x and y pixels) relative to the sky coordinates (RA and declination). When guiding, you measure centroid errors in camera x-y pixel units, and using the calibrations to compute the duration of guide pulses to the mount that make RA-declination corrections in sky coordinates.

Chen

Kevin_A

chaitanyakhoje i use weights for my lighter setups. Do not worry about the calibrations being on a angle just as long as they are at a 90 degree angle. Rigidity is a must with this mount and tripod, asni do it for all my rigs.

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