#21  
Old 15-07-2019, 09:03 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
Quote:
Originally Posted by benklerk View Post
I just ordered the CEM120EC with the RA encoder. Ordered it though Sidereal Trading so I have full Australian warranty on the mount. I should have it in about 3 weeks. I also got 4 counterweights and the permanent pier.

This is going along with all new gear, including a 14" RC with a G4-16000 camera with filters.

Cant wait to set everything up.
Nice.

I'll be ordering more counterweights later on when I load up my mount with a side by side setup and put at least 2 scopes on there (RC10 + Sharpstar 107PH and maybe the Coronado as well).

I got mine through Telescopes and Astronomy, so I also have Australian warranty/consumer protection.
Reply With Quote
  #22  
Old 28-07-2019, 02:30 PM
ghealey56 (Geoff)
Registered User

ghealey56 is offline
 
Join Date: Aug 2018
Location: Dandenong North
Posts: 4
Quote:
Originally Posted by benklerk View Post
I just ordered the CEM120EC with the RA encoder. Ordered it though Sidereal Trading so I have full Australian warranty on the mount. I should have it in about 3 weeks. I also got 4 counterweights and the permanent pier.

This is going along with all new gear, including a 14" RC with a G4-16000 camera with filters.

Cant wait to set everything up.

Ben
I have ordered a CEM60EC also through Paul Litchen at Sidereal Trading. Terrific services and I gather there are a few of us filled with iOptron anticipation!
Reply With Quote
  #23  
Old 14-08-2019, 09:09 AM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
Time for an update. I've had other things on my plate for a bit besides this hobby, so time has been an issue.

However, shortly after my last update, I got the mount on to the pier in the dome and loaded up the counterweights. Then to my shock, I discovered I could not get the RC10 or my other dovetail (for the refractor) on to the mount's saddle plate. I was very annoyed that I had not checked this beforehand while it was in the house, but it just did not occur to me that it would be an issue.

To cut a very long story short, I now have a replacement mount saddle plate that I received yesterday. My RC10 now fits it quite snugly. The other plate slides in/out much easier.

I held off on an update until this was resolved to ensure the full picture can be presented - overall support with iOptron has been good/ok given it's via email and massive time zone differences (they're in US east coast). It took nearly a month to sort out as I had to post the saddle plate to them first before they would send a replacement. I can understand this process, but it's still frustrating.

So, what was the issue you might be thinking? There's specs for what a losmandy dovertail should be, and theoretically there's also specs for the mount saddle plate too (as provided by iOptron). I hit the "perfect" combo of my dovetail plates being slightly over spec and the mount saddle plate slightly under spec. There's 2 significant measurements here - the narrow and large widths. For my problem it was the narrow width that caused the grief.

So while I was not "blameless" for this problem given the out of spec dovetails, iOptron really had the greater fault in not ensuring the mount saddle plate was correct spec. If they were at perfect spec, my dovetails would have worked, albeit with tight margins. Also, I personally believe their mount saddle plate is inferior to what I've used on the G11.

However, it should be noted that iOptron has come through and sorted out the problem for me.

I'm hoping I can do more with it tonight, weather permitting - and if we can get my dome rotation going again.
Reply With Quote
  #24  
Old 15-08-2019, 12:09 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
I did manage to do some more work on the setup yesterday/last night.

With all the time passing, I've become a little impatient, so I decided to put the RC10 on for the largest FL I've got to really test things out (so no FR, just the "vanilla" 2000mm F8 setup). I may need to collimate the scope, so this setup may change to my refractor depending on how that goes.

The first thing I discovered was that balancing the CEM seemed to be a little bit more tricky than the GEM. Part of this was related to only having 2 counterweights and the back heaviness of the RC10. Getting the RA balance close was not too difficult, but I had to adjust it if I made changes to get the DEC balance sorted (when shifting weight as well as the obvious add/remove weight).

The DEC balance was more difficult because of the saddle plate locking knobs. I wanted to ensure all 3 were used to grabbed the dovetail, so the RC10 was sitting back further than what I used to have on the G11. To sort out the lack of weight on the front, I found that using my solar scope mounted on the top rail did the trick - which is handy because I was planning to mount it there anyway.

Wiring up the mount is great now. I connect to the mount via ethernet, so that's one less cable to the computer. I also connect to the USB3 on the mount, and have wired up the camera, fw and guide cam to that. I'll be adding the focuser to that as well, but it means I have just one direct connection from mount to PC - USB3.

Not content with just changing one thing, I messed with a few other things, including the OAG I was using, a tilt adjuster, the spacing between the camera and the filter wheel, etc. This meant that it took me a while to sort out the correct backfocus. It didn't help when the guide camera got chosen instead of the main camera when I was trying to check things. It confused me until I realised what was happening and sorted it out.

Eventually I got a very rough focus in place and noticed the PA was quite whacked (well having done no PA so far, probably not a surprise. ). My dome still can't rotate, so I had a fixed opening to try to sort it out. I spent a bit of time trying to get it better, but I was still getting drift in one direction. I ran out of time to do any more (and I was getting tired), so I hope to continue tonight. I'll go back to basics and work it out from scratch.

I am starting to get used to the idiosyncrasies of the mount hand controller and the Commander software. There's a few things in each I would do differently (just like for the G11), but nothing that's completely broken. Probably the most annoying thing is having to power cycle the mount if you park using the hand controller. The Commander software allows you to unpark. Just the usual type of weirdness one gets with astro gear/software.
Reply With Quote
  #25  
Old 19-08-2019, 09:49 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
I've had a few hours over the last few nights to proceed further. I at least now have manual dome rotation so I can get to anywhere I want.

After much stuffing around, I came to the conclusion that I couldn't get the PA sorted using PHD drift align with the out of collimation RC10. I also discounted using the methods in the hand controller to do PA once I realised that I had no idea how to work out what dots on the screen were what stars it was asking for, even if they didn't all look like comets.

So, I've switched to the Sharpstar 107PH until I sort out the RC10, so testing at 700mm instead of 2000mm. Although I still managed to stuff around getting it done, it was of a lesser quantity.

I got the PA to 1.6' for the night using PHD Drift Align - I'll refine it more another time. Also, I need to experiment more with the PHD settings to find the most ideal setup.

I took a 10 min Ha exposure of M16 for a test. I then discovered I had some terrible tilt in the system:

Click image for larger version

Name:	L_Ha_2019_08_18_23_21_21_2019_08_18_23_21_21_G0_Bin1x1_600s__15C_eccentricity.png
Views:	4
Size:	14.9 KB
ID:	248183

I took 2 more images with similar results. For the first 2 I used 6 sec guiding (because that was the max I had in the dark library at the time). For the 3rd image, I used 10 sec guiding after creating the missing darks. I forgot to keep the PHD logs, but the guiding seemed "mostly fine", as in if I improved PA and tweaked the settings I could probably do much better.

I think I know what's causing the tilt (OAG is biggest suspect) and the next night I'm out I'll be trying to sort that out. If it wasn't for the tilt and some dodgy focus because of it, the 3 images I took would have been ok-ish.

I'd like to do a longer exposure for a test, but even at 0 gain, the ASI1600 was saturating parts of M16. I'll have to do a fainter/darker area to see how that goes sometime.
Reply With Quote
  #26  
Old 20-08-2019, 11:00 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
Ok, tilt was related to the OAG - a bit, but the major culprit was user error - I forgot to put the field flattener on. That made a bit of a difference.

Unfortunately, still not there yet as I have to adjust the back focus. The Celestron OAG I am trying out is using up too much of the back focus. I suspect I will need to go back to the TS OAG to make it all fit correctly.

I'm taking a few shots of M16 now, mostly to see how the tracking goes over a longer time.
Reply With Quote
  #27  
Old 21-08-2019, 03:51 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
Here's some guiding graphs from last night while I was taking 10min exposures of M16. I was using 5 sec guiding. I lost the star some time after the 2nd pic below - I haven't checked the results of all the exposures yet.

Click image for larger version

Name:	2019-08-20-phd-5sec.PNG
Views:	13
Size:	81.9 KB
ID:	248259

Click image for larger version

Name:	2019-08-20-phd-5sec_2.PNG
Views:	9
Size:	82.4 KB
ID:	248260

Beforehand I tried to improve the PA further. Adjusting the altitude was a lot more finicky than the azimuth and I think I will need to do a bit more there. Also, I'm not sure what the best DEC guiding algorithm to use - for this I used the resist switch.

However, overall I was fairly happy with the guiding results.
Reply With Quote
  #28  
Old 21-08-2019, 05:24 PM
Slawomir's Avatar
Slawomir (Suavi)
Amateur Photon Collector

Slawomir is offline
 
Join Date: Sep 2014
Location: Proserpine
Posts: 2,898
Thank you for sharing your guiding graphs Chris. RA looks really nice, I think DEC could be improved by lowering aggressiveness, because it goes up and down and corrections should be in one direction only? I would lower DEC aggressiveness to say 0.50-0.70 for a start, maybe even relax min movement to 0.25 in DEC? But it looks like the PA was a bit off?



Overall pretty nice consistent guiding graphs
Reply With Quote
  #29  
Old 21-08-2019, 06:08 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
Quote:
Originally Posted by Slawomir View Post
Thank you for sharing your guiding graphs Chris. RA looks really nice, I think DEC could be improved by lowering aggressiveness, because it goes up and down and corrections should be in one direction only? I would lower DEC aggressiveness to say 0.50-0.70 for a start, maybe even relax min movement to 0.25 in DEC? But it looks like the PA was a bit off?



Overall pretty nice consistent guiding graphs
Yes, I need to work out what the best setting is for PHD for this mount - it's very different to the G11.

I agree the PA is a bit off - that ALT was not easy to adjust. It's unlock 2 hex bolts, then adjust the knob which has a lot of play in it, then tighten up and test again. I think it's only the ALT that I really need to adjust now.

I'll sort the PA out before I mess around with PHD guiding again. And I'll consult some other CEM120EC2 owners about their thoughts on the DEC algorithm/settings to use. I do agree that the DEC seemed to react too aggressively.
Reply With Quote
  #30  
Old 21-08-2019, 06:43 PM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
 
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 1,644
M16 Ha, 9 x 10 min, ASI1600MM-C at Gain 0, Offset 10, dark calibrated, cosmetic correction, dizzle integration (@ x2). Only resized back down to "normal" frame size, no cropping, just jpeg compression at 70% to fit forum size. So, you can pixel peep to see the main problem with it...

Click image for larger version

Name:	M16_Ha_incorrect_spacing.jpg
Views:	8
Size:	194.7 KB
ID:	248271

..which is shown nicely in these images:

Click image for larger version

Name:	drizzle_integration_eccentricity.jpg
Views:	2
Size:	12.7 KB
ID:	248272

Click image for larger version

Name:	drizzle_integration_FWHM.jpg
Views:	2
Size:	9.1 KB
ID:	248273

The stars seem to point in to the centre, so I believe this means I need more space between the field flattener and the CCD. If so, that's a pleasant surprise since I had thought the reverse and was starting to puzzle as to what I could remove.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 06:40 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher Australia
Advertisement
NexDome Observatories
Advertisement
Lunatico Astronomical
Advertisement
OzScopes Authorised Dealer
Advertisement
Celestron Australia
Advertisement
Bintel
Advertisement
Meade Australia
Advertisement
Astronomy and Electronics Centre
Advertisement