Settings for AsiAir Plus Guiding: Page 4

Settings for AsiAir Plus Guiding

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.

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.

chaitanyakhoje

Kevin_A how does that extension help? Is it just for the height or does add to the stability? I only have the tripod right now and I saw better results with a 4.5 kg weight (not attached to the mount) and a jackery 300 battery (which I didn’t use) in the tripod bag.

Kevin_A

chaitanyakhoje the pe200 extension is just for my big 115 triplet so it clears the legs.

Kevin_A

chaitanyakhoje weights in the bag are helpful and i added the one to the mount undernearth just to add 10lb more. Extension is solely for long scope to leg clearance only and not for anything else.

MikeThun

Question for anyone: Just wondering if there is an advantage (or standard) to any particular guiding rate, ie., 1x, 0.9x, 0.5x sidereal?
I'm not sure if I would get better tracking or guiding by making a change. What is the purpose of these settings?
Mike

Kevin_A

MikeThun standard is 0.5x for most mounts and going lower to 0.25x will help smooth out guiding zigzag patterns with fast guiding. It is documented here in other threads, but unfortunately it is not yet available for the AM5 mount in asiair… only other mounts.

SFafveUb

w7ay Hello Chen, I’m having guiding issues when using autoguide with asiair. Long story short (well, not properly short): I’ve got my brand new HEQ5 Pro at the end of last october, my setup consists of:
ASI294 MC Pro,
Skywatcher 150/750 Newton or Redcat 51,
Guiding tube Ultraguide MkII 60/240mm,
Guiding Camera ASI120MC,
Asiair Plus.
Between the beginning of November and the beginning of January, I shot the Bubble Nebula and the Crescent Nebula both at 600” with autoguide with incredible guiding results, I discarded around 5/6% of the pictures taken because of slightly elongated stars; later on February I shot the Horse Nebula with great guiding again. Unfortunately the bad weather struck and I had to store the entire setup, everything well stored in bags and boxes. When, finally, I had the opportunity to take some pics again at the end of May, the guiding issues started, both with the 150/750 and the Redcat, I had very good guiding with exceptional RMS errors not higher than 0.40” but every now and then very high peak errors, both RA and DEC random, hit with RMS between 7 and 15” for very short periods giving, as result, elongated stars ruining also 2/3 of pics taken. Last night I was shooting again and I had the same guiding issue so I decided to test the Mount tracking at 120”, 180” and 300”… BANG!!! Great PICS with perfect round stars!!! So, as far as I know, it’s not a mount problem.
Any idea of what the problem can be?
Thank you
Raf

w7ay

SFafveUb so I decided to test the Mount tracking at 120”, 180” and 300”…

Can you explain what you mean by this?

In any case, I don't use iOptron mounts, so you need to ask someone else.

Chen

SFafveUb

w7ay hello Chen, I’m sorry I’ve been a little confusionary , I try to explain better: I have sudden and random peaks error while guiding both RA and DEC axis. So I tried to switch off autoguide and shoot pictures without autoguide trying 120, 180 and 300 seconds exposures and I had perfect pictures with perfect stars. I think that the issue that I experienced may be due to autoguide calibration or do you have any other idea? Because the pictures taken without autoguiding are ok, it shouldn’t be a mount problem. I have a Skywatcher HEQ5 Pro Mount.

SFafveUb

Hello, I just want to updat you all that I solved my issue just reinstalling the ASIAIR OS and everything started to work perfectly. Just as simple as that.
Cheers
Raf

DonE

w7ay This is some amazing info! I never truly understood what most of these settings were for until now. Thanks!

« Previous Page Next Page »