Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

CEM25P Off Target after Flip

  • Please log in to reply
4 replies to this topic

#1 vwmj1

vwmj1

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 06 Jun 2020
  • Loc: Gibraltar/Andalusia Espana

Posted 20 September 2020 - 05:42 AM

Under hits own control , i.e. no software such as APT or ASIAIR, when my CEM25P flips it is not on target. Well off actually, to the extent I haven't been able to identify how far off.  The original target is definitely not in the pictures.

 

What am I doing wrong?

 

I'm sure it's something to do with the set up and suspect it's related to Zero Position.

 

Polar Alignment is accurate. I always take my time with this, and ensure it hasn't moved once I've got all the equipment mounted and running.

 

I only do a one star alignment. When tracking the mount is locked on target with no slippage errors.

 

Meridian Treatment is set at 5 degrees.

 

Reading other threads I know this can be solved, but I've not seen a specific thread dealing with this issue.



#2 james7ca

james7ca

    Cosmos

  • *****
  • Posts: 8,871
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 20 September 2020 - 06:36 AM

Could be cone error that can be reduced (or corrected) by shimming the rings/dovetail. Also, you mount's polar alignment/setup/calibration procedure should help correct for cone error but it probably doesn't do so perfectly.

 

In any case, if you want automated, accurate framing after a meridian flip you'll probably have to use plate solving to recenter the target. The only other solution would be to develop a pointing model for your mount (requires special software and best used on a mount with absolute encoders).


Edited by james7ca, 20 September 2020 - 07:00 AM.

  • vwmj1 likes this

#3 ShortLobster

ShortLobster

    Vostok 1

  • -----
  • Posts: 120
  • Joined: 17 Sep 2016
  • Loc: Stamford, CT, USA

Posted 20 September 2020 - 08:08 AM

As mentioned above, the best solution is to do a plate solve after a meridian flip.

 

You want your meridian flip to be controlled by your imaging software. I use that mount with an ASIAIR Pro, which initiates the flip, plate solves a couple of times and then restarts guiding. It's been nearly flawless for me, with alignment after the flip at 179.9 degrees as measured in DSS. 


  • vwmj1 likes this

#4 vwmj1

vwmj1

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 06 Jun 2020
  • Loc: Gibraltar/Andalusia Espana

Posted 20 September 2020 - 09:24 AM

Thanks guys. Grateful for the advice.

 

I thought it might be a software required solution.  I am using APT, so I'll do that next night out.

 

Not got round to the ASIAIR. Saving it for a couple of weeks off at the end of the month.



#5 ShortLobster

ShortLobster

    Vostok 1

  • -----
  • Posts: 120
  • Joined: 17 Sep 2016
  • Loc: Stamford, CT, USA

Posted 20 September 2020 - 09:33 AM

I was a bit skeptical of the ASIAIR Pro, but have to say it was a game changer for me. So simple to set up for imaging, everything is integrated and works great. Still a bunch of features I hope they add (e.g., auto-focus, support for PHD2's PPEC algorithm), but totally usable for most of my needs already. 




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics