Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Mounts

Pages: 1 | 2 | (show all)
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Celestron CPC-1100 + PEMPro 2 = Results !! new
      #3719938 - 04/01/10 11:54 PM

So last night I spent all night outside in my 3rd attempt at running a proper Periodic Error asessment and correction with PEMPro 2. The Results are in!

Specs:
Mount: Celestron Nexstar CPC1100 w/ Stainless Steel Ball Bearing Modification (Custom Wedge Mounted)
Scope Used: Piggybacked Equinox 80ED w/ Barlow yielding 1.08 arc-sec/pixel.
Camera: Philips SPC900NC
Skies: Transparency 3/5, Seeing 4/5 (Quite good for here)

So my goal was simple.. Gather a bunch of data with PEC Off, Create the PE Curve and upload it to the mount, and then gather a bunch more data with PEC On. Compare results. What I wasn't prepared to do was pick my jaw up off the floor after it was all said and done!

PE Data from first run. (PEC Off)


The PE Curve was then created from this data set which yielded these numbers: PE +14.4/-11.9 arc-secs, RMS Error: 4.947

So I uploaded this PE Curve to the mount and started gathering more data.

PE Data from second run. (PEC On)


The PE Curve was then created from this data set which yielded these numbers: PE +2.7/-2.6 arc-secs, RMS Error: 2.388

And finally here is a screenshot of the comparison graph:
(Red= Before, Blue= After)



I am extremely happy with these results using this mount! I just hope the translate into much less work for my autoguider so my overall imaging experience gets much easier.

If anybody is interested in looking at my raw data you can download it here: CPC-PEMPro Data

One thing I did this time around that I'd like to point out was balance the fork arms carefully. (East/West) Prior to this I've never worried about it, but I'm sure it made a big difference in my overall numbers.

One thing I found when searching for CPC Periodic Error Data is that it was hard to come by. I hope this helps some people out in that regard. The next test will be Imaging, however the weather has gone bad again so it might be a bit.. I'll definately post a follow up in this thread. Thanks for reading! Any input is appreciated.

Edited by Psyire (04/02/10 11:38 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Yedgy
professor emeritus
*****

Reged: 07/22/08

Loc: Phoenix, AZ, USA
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3720116 - 04/02/10 03:33 AM

Nice job! I'll give you the benefit of the doubt that this isn't an April Fool's joke. You should repost your 2nd PEMPro run image, as the one in your post seems to be a copy of the first run.

Tony


Post Extras: Print Post   Remind Me!   Notify Moderator  
mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Yedgy]
      #3720371 - 04/02/10 09:51 AM

These results shouldn't be a surprise. The well regarded CGE mounts and Nexstar GPS scopes shared virtually the same motors and gears, the bearings however were different due to the very different mount types (gem vs. Alt Az/wedge). CPCs have only changed a little bit from the Nexstar GPS scopes, they still have the same size worm/spur gears and motors.

Nice to see someone take the time to get some numbers on the CPCs.


Post Extras: Print Post   Remind Me!   Notify Moderator  
lambermo
professor emeritus


Reged: 07/16/07

Loc: .nl
Re: Celestron CPC-1100 + PEMPro 2 = Results !! [Re: mclewis1]
      #3720564 - 04/02/10 11:29 AM

I don't get this. Your data shows :
Without PEC : PE +14.4/-11.9 arc seconds -> 26.3 arc seconds peak-to-peak
With PEC : PE +2.7/-2.6 arc seconds -> 5.3 arc seconds peak-to-peak
Yet your 'comparison graph' shows a peak-to-peak of 26.31 'before' and a 2.0 arc seconds 'after'. Where does this 2.0 come from

ps. as Yedgy already mentioned please repost your 2nd PEMPro run image.
-- Hans


Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: lambermo]
      #3720585 - 04/02/10 11:41 AM

Oops, got in trouble with the copy/paste function. lol I edited the above post to reflect the proper screenshots.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3720637 - 04/02/10 12:06 PM

Hans/Tony, thanks for pointing that out. I went back to PEMPro and ran the curves and comparisons again and came up with the proper numbers. I'm not sure why it didn't do this the first time but it looks good now. Of course 5.31 arc-secs Peak-Peak isn't as good as the 2.0, but it's still a great improvement!

Note: My original post has been updated to reflect this change!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: mclewis1]
      #3720670 - 04/02/10 12:23 PM

Quote:

These results shouldn't be a surprise. The well regarded CGE mounts and Nexstar GPS scopes shared virtually the same motors and gears, the bearings however were different due to the very different mount types (gem vs. Alt Az/wedge). CPCs have only changed a little bit from the Nexstar GPS scopes, they still have the same size worm/spur gears and motors.

Nice to see someone take the time to get some numbers on the CPCs.




Mark, I agree completely. I've always said that the CPC would give the CGE a run for it's money and now I've got the numbers to prove it. If you loaded a CGE with a C11 & an 80ED I'm pretty sure the numbers wouldn't be much different than mine...


Post Extras: Print Post   Remind Me!   Notify Moderator  
lambermo
professor emeritus


Reged: 07/16/07

Loc: .nl
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3721110 - 04/02/10 03:51 PM

Thanks for clearing up the data.
I've added your results to my list of astrophotography capable mounts at http://lambermont.dyndns.org/astro/pe.html you're the 75th entry
Now I need a payload measurement/guess for the 1100. Anyone ?

As well as 800 and 925 data ...

-- Hans


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike Clemens
Frozen to Eyepiece
*****

Reged: 11/26/05

Loc: Alaska, USA
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: lambermo]
      #3721185 - 04/02/10 04:42 PM

Great results! Thanks for posting them.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike Clemens
Frozen to Eyepiece
*****

Reged: 11/26/05

Loc: Alaska, USA
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Mike Clemens]
      #3721195 - 04/02/10 04:47 PM

lambermo, you link to my PEC picture on your page, (AP1200GTO) that was with 80 pounds of payload and 55 pounds of counterweights.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: lambermo]
      #3722910 - 04/03/10 04:31 PM

Quote:

Thanks for clearing up the data.
I've added your results to my list of astrophotography capable mounts at http://lambermont.dyndns.org/astro/pe.html you're the 75th entry -- Hans




Nice! Thanks for posting that link as I haven't seen your page before. Interesting to say the least.. Do you want the payload rating of just the scopes+equipment or the whole shebang with fork arms and everything?


Post Extras: Print Post   Remind Me!   Notify Moderator  
lambermo
professor emeritus


Reged: 07/16/07

Loc: .nl
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3723734 - 04/04/10 04:06 AM

Quote:

Do you want the payload rating of just the scopes+equipment or the whole shebang with fork arms and everything?




Just the payload (OTA+equipment) so it can be compared to the other mounts. This is a little hard as your OTA is integrated ;-) and Celestron does not clearly specify its mass nor the maximum attachment/piggy-back load AFAIK.
So I'm fine with an educated guess here ;-) I had to do the same for Meade's LX200.

ps. payload does not include counterweigths. This may sound trivial but vendors like Vixen mention 'load capacity' and 'load weight', which is payload plus counterweights
pps. Another payload thing is the reported payload of Takahashi's EM-11 : it's 9 kg at http://www.takahashi-europe.com/en/EM-11.specifications.php and 11 kg at http://takahashiamerica.com/bottom_mounts.htm


Post Extras: Print Post   Remind Me!   Notify Moderator  
Patrick
Postmaster
*****

Reged: 05/16/03

Loc: Franklin, Ohio
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3724400 - 04/04/10 02:56 PM

Psyire,

That looks really good. With PEC runningand at shorter focal lengths and exposures you could probably get away with not guiding at all.

Patrick


Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: lambermo]
      #3724463 - 04/04/10 03:33 PM

Quote:

Just the payload (OTA+equipment) so it can be compared to the other mounts. This is a little hard as your OTA is integrated ;-) and Celestron does not clearly specify its mass nor the maximum attachment/piggy-back load AFAIK.
So I'm fine with an educated guess here ;-) I had to do the same for Meade's LX200.




Not sure if others would agree but my educated guess is 25kg. The CPC mounts seem to be able to hold anything the CGE except there is no 14" SCT version.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Patrick]
      #3724483 - 04/04/10 03:41 PM

Quote:

Psyire,

That looks really good. With PEC runningand at shorter focal lengths and exposures you could probably get away with not guiding at all.

Patrick




I was thinking that too Patrick, expecially DSLR lens work. Which it looks like i might have to try! (50mm 'ish)


Post Extras: Print Post   Remind Me!   Notify Moderator  
DaemonGPF
Redonkulous
*****

Reged: 03/22/08

Loc: Aurora Colorado
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3725068 - 04/04/10 09:25 PM

This is good news. I'll be doing this with an NS8 GPS shortly. I'm interested to see what the difference would be with the lighter config, and on the older design.

Post Extras: Print Post   Remind Me!   Notify Moderator  
mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3725832 - 04/05/10 10:09 AM

Quote:

The CPC mounts seem to be able to hold anything the CGE except there is no 14" SCT version.



I wouldn't go quite that far. The fork mounting puts a lot of stress on the azimuth bearing since there is no counterweight. There is no way I'd want to put 60+lbs of instrument payload on a CPC or NS GPS fork mount. This is especially true at lower lattitudes ... the lower the less the mount will be able to carry, the higher the more the mount acts like an Alt Az and the less stress on that Azimuth bearing there is.

I think 20kgs/44lbs is probably a safer number that would cover a wider range of setups on a fork mounted CPC or Nexstar GPS scope.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: mclewis1]
      #3726496 - 04/05/10 03:43 PM

Quote:

I wouldn't go quite that far. The fork mounting puts a lot of stress on the azimuth bearing since there is no counterweight. There is no way I'd want to put 60+lbs of instrument payload on a CPC or NS GPS fork mount. This is especially true at lower lattitudes ... the lower the less the mount will be able to carry, the higher the more the mount acts like an Alt Az and the less stress on that Azimuth bearing there is.

I think 20kgs/44lbs is probably a safer number that would cover a wider range of setups on a fork mounted CPC or Nexstar GPS scope.




Valid points for sure. 20kgs seems like a reasonable number.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Psyire
Pooh-Bah
*****

Reged: 06/24/07

Loc: 55* North
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3761916 - 04/22/10 05:28 PM

UPDATE
--------

I was finally able to test out the effectiveness of having PEC enabled while imaging a few nights ago. Here are the results:

M106, 5min subs, C11 @ F/6.3 = FL:1763mm (PEC On & Autoguiding)
(Click for 1200 Wide)


M51, 10min subs, C11 @ F/6.3 = FL:1763mm (PEC On & Autoguiding)
(Click for 1200 Wide)


All in all I think it's working great, I couldn't get these results with relying on autoguiding alone.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Peter in Reno
Postmaster
*****

Reged: 07/15/08

Loc: Reno, NV
Re: Celestron CPC-1100 + PEMPro 2 = Results !! new [Re: Psyire]
      #3761946 - 04/22/10 05:51 PM

Did you use OAG or guide scope? If you used guide scope, did you see image shift in between subs especially for 10 minute subs?

BTW, very nice photos!

Peter


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
23 registered and 44 anonymous users are browsing this forum.

Moderator:  Dave M, richard7, bilgebay, iceblaze 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 5708

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics