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ZEQ25 PE Curve

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#26 John Miele

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Posted 29 October 2013 - 08:53 PM

You got it! Here is the just the first two frequencies plotted and I used the Vixen GP mount option...

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#27 John Miele

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Posted 29 October 2013 - 08:55 PM

And here is the frequency data. There sure is a big spike at that other frequency...is this something to try and work on? The mount seems to guide fairly well...I'll post a single cropped 5 minute sub shortly...John

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#28 orlyandico

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Posted 29 October 2013 - 08:56 PM

well... there is no change in the peak-to-peak PE. So the first two harmonics are really the bulk of the PE..

If the 160-second harmonic is from the gearbox, it will not be removable (just like the CGEM 8/3 problem). I would really appreciate seeing an "after" graph once you've cleaned up the mount.

I'd be interested to see the results of others in the above format.. not because I'm nitpicking this mount (no point..) but because I've been thinking about getting one myself for travel. But honestly if they mostly have that much PE.. I'd probably go back to my plan B of looking for an old EM10/EM11/P2Z..

#29 John Miele

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Posted 29 October 2013 - 08:59 PM

Post deleted by John Miele

#30 John Miele

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Posted 29 October 2013 - 09:15 PM

I'm not really going to do any cleaning. I'm just going to adjust the worm gear mesh and RA play and make sure I have no slop in the worm bearings. I'm also going to investigate the stronger spring option. It will be several days before I can post back an "after" comparison. Here is a single 5 minute randomly picked sub @ 100% crop...John

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#31 John Miele

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Posted 29 October 2013 - 09:25 PM

Hi Paul,

Here is the plot of just the Mag Period...


Hope the graph here is a useful data point for someone...
John


A couple of minor points John. The worm period for the ZEQ is 600 seconds, so you need to set that in PecPrep. You have it set to 479.

After you load your PHD log, check 'Mag Period' and uncheck all the other boxes to see the raw PE in the mount.

Oh, once you tighten up the mount a bit, it will improve.

Good luck and thanks for the data.

Paul

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#32 Astronewb

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Posted 29 October 2013 - 09:31 PM

You got it! Here is the just the first two frequencies plotted and I used the Vixen GP mount option...


You're getting there. But the Z is not a Vixen. In PecPrep, under mount types, create a type 'ZEQ25', set the worm period to 600 seconds, just '1's on the rest.

In the 'Tag' box, delete any reference there, they are for the common Synta mounts and don't apply to the Z. (I see that gear 5 entry in the drop down box..shouldn't be there)

Hit 'Save changes' and the ZEQ25 will appear in the menu.

You can enter the number of worm teeth (144) but since PEC is not permanent in the Z mount, I can't see any reason for creating a PEC curve.

If you can make those changes and post up just the 'Mag Period' results, I'd like to see it?

Oh, and here's a link to a 70 minute guided exposure taken (by mistake) off the ZEQ: http://www.flickr.co...011/8719442364/

Thanks...Paul

#33 orlyandico

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Posted 29 October 2013 - 10:43 PM

For purposes of PECPrep, the Z is a Vixen, with a 598-second worm period (not 600-second). All that PECPrep cares about is the number of worm teeth. Since the Z has 144 teeth, its worm period is (86164 / 144) = 598 seconds.

You can use the corrected King rate so (86188 / 144) = still 598 seconds.

#34 John Miele

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Posted 30 October 2013 - 05:17 PM

I made the plot Paul asked for and I think Orlandico is right. There does not seem to be any difference. One point to note: when I open PECPREP and uncheck everything but the Mag Period box, the data terms (max and min PE, etc.) all become zero. But if I move to another tab and then back to the main page, the data fills in. I do not know if this is a PECPRO glitch or if it affects the answers. But here is the plot anyway.

I think however, as Pauls images show and many others as well, that regardless of the starting raw PE plots, this mount responds to autoguiding very well and can produce some nice images. But I know we all love to deep dive into this type of thing!

John

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#35 cloudywest

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Posted 30 October 2013 - 07:25 PM

Since the Z has 144 teeth, its worm period is (86164 / 144) = 598 seconds.
You can use the corrected King rate so (86188 / 144) = still 598 seconds.

The true peroid is 23.9344699*3600/144=598.36. Many people include me use 24*3600/144=600

#36 Astronewb

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Posted 30 October 2013 - 08:03 PM

Thanks John, just wanted to make sure PecPrep was behaving, and obviously it is. Orly is the guru of Pec, no doubt.

Cloudywest is the guru of mathematics, my hat's off to you.

I'll use the 24*3600/144=600 too, not because I can do the math, I just like round numbers...:)

Thanks all, for the info. I'm still waiting for a night clear enough to actually run a 50 minute raw PE exercise.

Paul

#37 Astronewb

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Posted 01 November 2013 - 09:54 PM

Take the mount somewhere you can drift align it properly and repeat the test, and not make any assumptions that is 5 seconds peak to peak.



Well, I was hoping for about 5 arc-seconds, peak to peak but that's not how it turned out. Guess I'll have to settle for about 2 arc-seconds average with 7 arc-seconds peak to peak, bummer.

Guiding scope was a Borg 50/250mm and a Lodestar. Guiding was disabled after calibration and a new PHD log file created. Declination was compensated for (+42).

This is with a mount polar align and a One Star align. Life is too short to drift align. Astro Tech AT6RC in the mount with the Borg 50mm piggybacked in its normal position.

Larger res on Flickr:
Posted Image
ZEQ_raw__PE_110113 by Astronewb2011, on Flickr

Hope the info helps,

Paul

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#38 orion69

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Posted 01 November 2013 - 11:27 PM

Correct me if I'm wrong, is this actually measured using Borg 250mm FL?
Is graph compensated for FL of the main scope?

#39 Astronewb

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Posted 01 November 2013 - 11:56 PM

Correct me if I'm wrong, is this actually measured using Borg 250mm FL?
Is graph compensated for FL of the main scope?


I've asked on a few forums, and have been informed, the correct method is the focal length of the guidescope, not the imaging scope.

Makes sense to me, since PHD is gathering the data through the imaging scope.

Perhaps someone has some other information or can add some information?

Best...Paul

#40 orlyandico

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Posted 02 November 2013 - 01:32 AM

1) interesting that your mount also displays the 200-second harmonic that is very strong (in John's case it was 160 seconds), in your case almost as strong as the fundamental.

2) what is the reported PE with only the 584-second component checked? and with the 584- and 200-second?

Can you post the PHD log file? (as alph would say, where's the logs..)

#41 freestar8n

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Posted 02 November 2013 - 02:20 AM

Or as Frank would say - what is the actual fwhm you are achieving in your guided images, in arc-seconds? Logs only tell you what the guider thinks is happening - and it can be far from what is actually happening in the image - especially when using a small guidescope. The image is what matters, unless your goal is to frame a plot of the guide log and put it on the wall.

Frank

#42 Astronewb

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Posted 02 November 2013 - 02:46 AM

The image is what matters, unless your goal is to frame a plot of the guide log and put it on the wall.


I never thought about framing a graph, but it sounds doable.. :)

I agree 200% Frank, the image is what matters, bottom line.

So here's a link to some images acquired with the ZEQ and various ota's:

http://www.flickr.co...57632878588706/

Right click the images, check the 2048 or original full res image, and let me know how many egg shaped stars you find?

All the best...Paul

#43 Astronewb

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Posted 02 November 2013 - 02:55 AM

@ Orly ... Really?

All I can say is, at least my PecPrep actually shows the compensated declination (unlike another graph from a really big mount) which continually shows '00'.

Harmonics may be interesting, but all I really cared about was posting a raw PE curve. Done, and done.

Regards...Paul

#44 jonee523

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Posted 02 November 2013 - 03:26 AM

Paul, all I can say is thank you for the wonderful information you have shared with those of us who are looking to dive into AP with a lighter budget then some. the information you have shared with us all has helped many including myself decide on a mount for viewing and AP. I can't say I know what all these graphs are. But I can say for visual I know it will be fine. For AP I have seen a lot of pics here and I am very impressed. I look forward to "attempting" AP. If all holds to plan come tax time.

Best regards,

Jon

#45 Astronewb

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Posted 02 November 2013 - 08:19 AM

@ Jon

Thanks for the nice comments Jon. All I can say about this mount is that, if you're in the 'astrophotography on a budget' mode, then I highly doubt if you will find a better device to get the job done in it's price range.

Your comment made me stop and think, and I can't remember ever doing any visual with the mount. I guess if it will take a 70+ minute image by mistake, with minimal trailing, it can handle an eyeball? :)

Good luck with tax time, keeping my fingers crossed for you!

Regards...Paul

#46 orion69

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Posted 02 November 2013 - 08:49 AM

Correct me if I'm wrong, is this actually measured using Borg 250mm FL?
Is graph compensated for FL of the main scope?


I've asked on a few forums, and have been informed, the correct method is the focal length of the guidescope, not the imaging scope.

Makes sense to me, since PHD is gathering the data through the imaging scope.

Perhaps someone has some other information or can add some information?

Best...Paul


I don't know where did you get that info but it can't be correct. If you want real PE plot then you'll have to use main scope and even then you have to take into account difference in pixel size between guiding camera and main camera.

#47 anat

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Posted 04 November 2013 - 02:08 AM

I got 20 arcsec (P-P) from my ZEQ25 :) The following image shows the raw tracking error in arcsec (Y axis) from an autoguiding software (Linguider) with no correction signal to the mount. Note that the time in the X axis was obtained from multiplying the step and 2sec (exposure time). It should have been the step x 2.x sec.

Anat

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#48 ramasule

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Posted 05 November 2013 - 10:08 PM

It's not even that this is a astrophotography on a budge mount. It's a legit portable astrophotography mount. This thing really is nice.






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