jusasi

7 hours ago, michael8554 said:

Your PA looks fine, the Guide Assistant run reported 1.4arcmins, anything less than 5 is guideable.

The GA run shows the mount has Periodic Error, that's why RA is heading south off scale, but 15arcsecs isn't bad actually.

So RA could be tamed with Guide Rates upped to 0.8x and fettling of PHD2 settings, maybe try the PPEC Guide Algorithm?

You have huge out of spec Dec backlash, over 58.072 seconds, I'd return the mount with a print of that reading.

Michael

Thanks for the analysis!

Yeah, the Dec backlash seems bad - I might just go ahead and return it on that basis alone. If the skies stay clear enough I'll definitely try your tips.

Also I didn't mention my gear, I totally forgot:

 

- The scope is a 70mm refractor with 420mm focal length, reduced to 336mm with a reducer.

- The guide scope is a 50mm / 162mm focal length basic scope.

- The main camera is ASI1600MM, guide camera is ASI224MC.

- ASI filter wheel.

- Total weight of that setup is 3.8kg.

 

I bought the mount intending to use it as a travel mount, and figured from the specs that it would do fine for this load. It felt sturdy enough but looks like the machinery is a bit lacking. Also if it's finicky to get it to guide just right, it probably isn't exactly a the kind of mount I'd use for travel - I do not want to spend all night troubleshooting on-site after all.

 

1 hour ago, Miguel1983 said:

Hi, at first glance i see similar things i've encountered with my EQM35-pro.

I have this mount since January and tried to use 3 times now, i had invested is a pocked powerbox, a USB hub and a small laptop to make this my second lightweight imaging rig, boy was that disappointing.

The aim was to use EQMOD without the HC directly trough a eqdir cable.

Calibration wouldn't finish, or return a prompt of "unexpected value's" or "star didn't move enough" etc.

Tried to guide with the HC and with ST4 cable, so no eqmod involved, no luck.

Basically, a gave up, i don't need this with a new mount, now its sitting there gathering dust, conclusion for me is don't buy anything less than a heq5.

Someone way smarter than me would probably adjust the eqmod settings, but i wouldn't know where to start.

I should have just returned it to FLO, or at least contacted them, but with all that bad weather we had in january, february and first half of march i'just didn't find the courage to keep on testing/trying

 

I hope you get this sorted, i will follow along, maybe there's a solution here

So we're pretty much on the same boat here. Had that "star didn't move enough" once or twice on my first try as well.

I've now spent 3 days looking at this thing and wondering how to tame it, and had to come cry for help. Definitely not a mount for the inexperienced.

Ok, please bear with me as this is may be a bit long and highly illustrated. I've tried to record my struggles as detailed as I could in the hopes of getting some help from you guys, so I beg you to read this carefully if you have experience with guiding issues and/or with the EQ3 Pro (SynScan) mount - I only got this mount about a week ago and I'm still wondering whether these issues is something that can be solved or to be expected, or whether I'm dealing with damaged goods.

So here we go. Bottom line, what is your judgement: is this correctable, is there something very wrong with the mount, or is this to be expected of this specific mount? I have until Friday to return this (14 day return policy), and if this is a lost cause, I'd like to know about it.

 

Two days ago I initially tried out this mount quickly, I managed to set it up and align it as a practise and fired up KStars/Ekos and PHD2 to see how this baby worked. Weather happened and I didn't quite get to the bottom of it - I did image for a few frames and quickly noticed that while initial calibration went ok, guiding was all over the place. Stars were very oblong on a 3 minute exposure. This didn't worry me much since the sky was getting cloudy and I therefore was a bit bad for testing, but I wanted to get a quick taste of it anyway.

 

Fast forward to yesterday. Skies were clear, and it was time for more testing. First of all I wanted to see how the EQMod driver worked (instead of using the SynScan driver), i.e. turning on the Direct PC Mode from the controller and going all computerized. No big issues there, except for the horizon limits which suddenly stopped tracking several times. Once I figured this out and disabled the limiting, no issues (except KStars/Ekos did not seem to save this setting). In any case, fast forward to guiding: again the PHD2 graphs were all over the place. A six hour of battle of calibrations/alignments/mount balancing ensued. It was not a pretty sight... in the end I decided to surrender to fight another day and swore that this time I'd properly document these issues. And that's where we are now.

 

So tonight I tried again. Let's start.

 

The mount was aligned quite closely to celestial pole from previous sessions. I re-balanced the mount, RA first, then DEC. I powered on the mount, set up date/time/location and engaged Direct PC Mode and fired up KStars/Ekos.

My balcony has no direct sight of Polaris, so I had to veer a bit off to the East to perform polar alignment with the Ekos. I ran the alignment procedure twice, and got pretty close. Finished the alignment using PHD2 Polar drift alignment tool, with PA Err 3 min after letting it stabilize for 3 minutes. Spent a good hour on the entire polar alignment procedure to make sure that a poor polar alignment wasn't going to be an issue.

 

At this point I was happy so I decided to navigate to a few stars and ran Ekos alignment.

After slewing to a target the captured camera alignment image looked like this:

 

 

I have a settle time of 15 seconds on my alignment/solver - even then that's how it looks. The drift after running GOTO appears to be quite a lot. The backlash must be huge or something.

 

Alright, trying PHD2 guiding then:
Using ST4 guiding, since the mount supports it.
Calibration done pointing East. East-West movement looks good. 21 steps of clearing backlash. I make a note that the mount makes a click sound when moving north on every step.

Another note with South steps: virtually no movement whatsoever. Dist stays at ~29.

Result: Calibration completed but RA and Dec rates vary by an unexpected amount (often caused by large Dec backlash)
Calibration results as below.

 

 

Guiding starts. The graph makes me want to cry. Dec is somewhat workable I think, but RA is bouncing all over the place.

 

 

Running the Guiding Assistant next to get some insight.
Oh boy, no amount of polar alignment is going to fix this:

 

 

Guiding assistant results below:

 

 

Ok, so something's majorly screwed up here. I'm really hoping someone with knowledge can pitch in!

 

So let's try a star-cross test then. Might as well do everything while we're at it. In fact, let's do it a second time, and a third time in another part of the sky.

 

 

Again, noticing from viewing live picture from PHD2 that the drift after slew is very noticeable and long.

 

Now again, for science, let's ditch ST4 guiding and go with mount only. After all there are probably differences!

Calibration East-West: the West direction appears to be flipped. West steps with ST4 went to the other direction! This just got interesting.
North-South direction is identical to ST4 however. Little south movement again.

 

RA is still flipping all over the place.

 

 

Of course what really matters in the end is how the images look like. Obsessing over numbers is one thing and looking at actual images is another. So, let's take a look at a 180sec guided frame. The stars looks like this:

 

 

Not great, not terrible. But oblong and gets worse the longer the exposure gets.

I think I could work with the Dec, especially with all the settings to adjust it and the backlash, but the RA is just wreaking havoc.

This probably enough for now. On the previous night I literally tried balancing everything multiple times, even off-balance to both directions to see what the effect might be and yet this seemed to have no visible effect on the guiding graphs, everything jumped as wildly as in perfect balance. So that has been tried and tested. Also during that night the calibration without ST4 created absolutely wild results, with a huge overshoot East-West. Like this:

I really have no idea what was happening there.

In any case, it looks like the RM Error in Dec can be held within ~1", but RA easily goes over 2.5". And this is a real issue.

 

Bottom line, what is your judgement: is this correctable, is there something very wrong with the mount, or is this to be expected of this specific mount? I have until Friday to return this (14 day return policy), and if this is a lost cause, I'd like to know about it.

Thank you for reading! I'm gonna go sleep now and hopefully my subconscious can make something out of this.