4 replies to this topic

[mtaivalmaa]

I have my C8 Edge HD ~2100mm (no reducer) at a remote observatory.. I just switched from the AM5 to used CEM60 as I was pushing close to max load on the AM5 and guiding started to have issues.. 

 

Resolution 0.38" per pixel

Dawes Limit: 0.57 arc/secs

 

My thought was the CEM60 would be at about half weight to load compared to the maxed out AM5

 

Now with the AM5 I had a 70ED as my guide scope and have now moved to a 50mm SvBony 180mm FL guide scope due to pier and swing radius the CEM60 sits higher and I don't want to pay more for my pier regardless shouldn't matter much.

 

I have the USB to serial cable connected and the ASIAIR sees the mount no issues.. seems like home is fine pointing at the Pole When I slew to a target everything seems fine plate solves and all good. 

 

It was Polar Aligned using sharp cap and when I checked it with the ASIAIR it was between 3' and 2' Arc mins (not sure if this is an issue) I will check it again as I get mins and secs confused sometimes. 

 

It seems like my RA doesn't get in sync and doesn't react to aggressiveness settings  the Dec I have had at 0.8 and under but I have yet to be under a total of < 1 RMS which I could do on the AM5 without any major wind etc. 

I would think that the CEM60 could do 0.8 or lower with my setup.. 

 

I have no experience with the CEM60 and sent it directly to the remote observatory so have only seen it in pictures but seems like it is working 

 

I am attaching my guide logs from the asiair that can be viewed in PHD Viewer  https://drive.google...iew?usp=sharing

 

I am going to have the team at the remote obs take another look any thoughts would be great .. its a test of my patience as I normally would go outside and mess with it until I figured it out.. the cost of a B1-B2 sky .. 

 

I have also reached out to support at iOptron but not sure if they will have any insight. 

 

Thanks Mike

 

 

 

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[michael8554]

1.  "Resolution 0.38" per pixel"

DSO imaging ?

Then Oversampling, binning would improve the figures you need to guide to.

 

2. "Polar Aligned using sharp cap and when I checked it with the ASIAIR it was between 3' and 2' Arc mins (not sure if this is an issue)"

5arcmins or less is fine to guide with.

 

3. "Pixel scale = 12.72 arc-sec/px, Binning = 2,"

The PHD2 developers say up to 3arcsecs/pixel is good, then gets progressively worse, up to a useable max of about 6. 

12.72 is crazy large.

So don't bin the guidecam.

 

4.  Minimum Moves are set to about 1.25arcsecs.

That means correction doesn't start until the guide errors have exceeded 1.25arcsec.

No chance of sub-arcsec guiding !

 

Correct your settings and try again.

Edited by michael8554, 05 August 2024 - 04:10 AM.

[mtaivalmaa]

1.  "Resolution 0.38" per pixel"

DSO imaging ?

Then Oversampling, binning would improve the figures you need to guide to.

 

2. "Polar Aligned using sharp cap and when I checked it with the ASIAIR it was between 3' and 2' Arc mins (not sure if this is an issue)"

5arcmins or less is fine to guide with.

 

3. "Pixel scale = 12.72 arc-sec/px, Binning = 2,"

The PHD2 developers say up to 3arcsecs/pixel is good, then gets progressively worse, up to a useable max of about 6. 

12.72 is crazy large.

So don't bin the guidecam.

 

4.  Minimum Moves are set to about 1.25arcsecs.

That means correction doesn't start until the guide errors have exceeded 1.25arcsec.

No chance of sub-arcsec guiding !

 

Correct your settings and try again.

Thank you Michael.. Great feedback.. I will check all of those out and report back.. 

I know I am bin2 on guide scope so that is a easy change. I am doing DSO imaging I understand I am oversampling on Bin1 but will deal with that once guiding is under control.. 

 

I will double check my PA but pretty sure I am under 5arcmins 

 

Minimum moves are set to 1.25arcsecs.. I need to see if this is in the asiair guide settings or somehow configured with the CEM60 hand controller 

That would make sense as to the main issues. 

[BobW55]

I have a cem60 and use ASIAIR exclusivly.  My Mount would guide at 0.4 or less all night long.  AT130EDT scope, 2600mcp camera.  60mm Guide scope with 220mm camera.

Best thing to do is post a pic of your entire ASIAIR guide screen, make sure show corrections is turned on.  Can tell more from the pic than the logs.

 

Side note:  I recently replaced my CEM60 drive belts only.  Now my guiding is terrible, I hear a grinding in the RA drive.   Thinking of sending to Ioptron for a tune up.

[mtaivalmaa]

It's been better of late strange thing is I have to recalibrate the guiding every night. Been 1 to 0.5 depending on the night. My hands are tied a bit as it's at a remote site.

Edited by mtaivalmaa, 05 September 2024 - 01:01 PM.