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Re: PemPro Polar Alignment differs East to West
Andrew Jones
Hi Ray. It was pretty much the same for both Alt and Az. I ran it a couple of times and some runs it showed up to a 7 arc mins difference in Az, but pretty much stayed in the 3-5 arc min range for Alt.
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Re: PemPro Polar Alignment differs East to West
Joe Zeglinski
Rolando,
I think I have found the solution to solving the
east-west PemPro curve difference. Simple really.
Atmospheric refraction is ALREADY being taken into
account by Ray’s PemPro algorithm, so it really should not be an issue here.
However, if there is even some slight variation, during the target run, greater
in the western part of the sky, one could very easily produce an “Averaged
East-West Pier side” curve by the following procedure:
Doing PemPro this way, the target has the SAME amount of
EVER decreasing & then increasing atmospheric refraction, for the same
number of cycles, split between the two sides of the pier.
What might make this easier, would be if PemPro could
make a note of the “actual” pre-meridian offset angle – since the user may have
caused some angle delay in preparation of the run, such as the required
Calibration wizardry, and run the other HALF of the cycles until the same
post-meridian angle is reached. At that point, PemPro automatically ends
itself, in preparation for the resulting raw data curve analysis
phase.
The option screen may need to be changed from choosing
the number of cycles, or duration – to time or angle ahead and after crossing
the meridian.
I think this would be ideal.
Joe Z.
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Re: PemPro Polar Alignment differs East to West
Roland Christen
Hi Joe,
toggle quoted messageShow quoted text
Thanks for your thoughts. One could try the zenith to see if the drift in Dec is the same on either side. By the way, I got to thinking about your daytime polar alignment routine and decided to modify it for our new mounts that have the 90 degree engraving marks on the axes. You must have the pier or tripod level for this to work. All you have to do is line up the RA and Dec engraved marks with the scope pointing to Park3 position (Home position) and tighten both sets of clutches. Then send the mount to either Park1 or Park4 and level the telescope tube assembly using the altitude adjuster. That's it, and now all you need to adjust is the azimuth angle and that can be done by sending the scope to the Sun (with proper filter or use the ring shadow method). Turn the azimuth until the Sun lines up with the scope. You may have to move the RA axis a small amount using the E-W buttons if your keypad time is off, then press Recal. Now you are ready to slew to other bright planets or stars. Rolando
-----Original Message-----
From: 'Joseph Zeglinski' J.Zeglinski@... [ap-gto] <ap-gto@...> To: ap-gto Sent: Sat, Mar 3, 2018 2:32 pm Subject: Re: [ap-gto] PemPro Polar Alignment differs East to West Hi Rolando,
I too have seen that PemPro curve results discrepancy on
runs east vs. west side of the mount.
I REALLY like your explanation, on the cause – even if the results might
sometimes be slight. They could be further exaggerating with poor seeing,
besides the atmospheric component adding to the discrepancy.
Yes - if you run PemPro with the “standard” setting of 5
minutes (deg ?) looking toward the east of PM, the OTA is “rising” and the
atmospheric refraction is “actually improving”, all during the hour long RAW
data sampling.
On the flip side, running with exactly the same PemPro
meridian target offset, the atmospheric refraction can ONLY
“degrade” steadily for the entire western sky target run.
So, you have the worst of both situations. You can
either trust the optimum raw data when PemPro runs from the west side of the
pier on eastern targets, or the twice as bad situation with “STEADILY
declining” target Altitude ... when running with the scope on the east
side (looking west).
I brought this up, on this Group probably more than a
couple of years ago, suggesting that PemPro could be run twice, and the two raw
data curves averaged – or their samples interleaved – to come to some averaged
curve result. Requires some further thinking, whether the results “should be
weighted” more toward eastern targets, Something for Ray to consider, based on
your premise.
Anyway, Rolando, thanks for this explanation of what has
been frustrating me about my own PemPro results ... for a VERY long time.
Unfortunately, in the short term, we just have to live with this minor
discrepancy.
Joe
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Re: PemPro Polar Alignment differs East to West
Joe Zeglinski
Hi Rolando,
I too have seen that PemPro curve results discrepancy on
runs east vs. west side of the mount.
I REALLY like your explanation, on the cause – even if the results might
sometimes be slight. They could be further exaggerating with poor seeing,
besides the atmospheric component adding to the discrepancy.
Yes - if you run PemPro with the “standard” setting of 5
minutes (deg ?) looking toward the east of PM, the OTA is “rising” and the
atmospheric refraction is “actually improving”, all during the hour long RAW
data sampling.
On the flip side, running with exactly the same PemPro
meridian target offset, the atmospheric refraction can ONLY
“degrade” steadily for the entire western sky target run.
So, you have the worst of both situations. You can
either trust the optimum raw data when PemPro runs from the west side of the
pier on eastern targets, or the twice as bad situation with “STEADILY
declining” target Altitude ... when running with the scope on the east
side (looking west).
I brought this up, on this Group probably more than a
couple of years ago, suggesting that PemPro could be run twice, and the two raw
data curves averaged – or their samples interleaved – to come to some averaged
curve result. Requires some further thinking, whether the results “should be
weighted” more toward eastern targets, Something for Ray to consider, based on
your premise.
Anyway, Rolando, thanks for this explanation of what has
been frustrating me about my own PemPro results ... for a VERY long time.
Unfortunately, in the short term, we just have to live with this minor
discrepancy.
Joe
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Re: PemPro Polar Alignment differs East to West
Ray Gralak
Going from 1 to 3-5 arc-mins is actually not that much. Was the change mostly in azimuth, altitude, or both?
toggle quoted messageShow quoted text
It could be that weight shift from the pier flip is causing some movement. -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma
-----Original Message-----
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Re: PemPro Polar Alignment differs East to West
Roland Christen
I went thru the same process with our remote scope in Chile several years ago. We had the polar alignment dead on with no movement in Dec for many minutes. The mount is a 1600 and scope was a 12" Mak-Cass astrograph. When we switched the scope to the other side and checked alignment on the west side, it was off, much to my amazement. In both cases the Dec axis was sitting still, not being driven. I have tried to simulate this motion via computer analysis, but no matter what changed, the alignment should remain exactly the same on either side of the axis. Even with the RA and Dec axes out of square the drift is still zero in both cases.
toggle quoted messageShow quoted text
It then dawned on me that at the long focal length of the 12" scope, the effects of atmospheric refraction caused a small change in the star's declination. So on one side it drifts up slightly over time and on the other side it drifts down on the chip. I finally set the azimuth so that the drifts were equal on both sides rather than zero. I might be totally wrong about this effect and its cause, but I have seen this on all the mounts that I have set up here at my observatory using PEMPRO polar alignment routine. Rolando
-----Original Message-----
From: andrew.jones@... [ap-gto] To: ap-gto Sent: Sat, Mar 3, 2018 1:08 pm Subject: [ap-gto] PemPro Polar Alignment differs East to West Hello Everyone. I am looking for some guidance. I have a Mach 1 on a permanent pier in an observatory that I am in the process of getting setup. I currently have a 11" EdgeHD SCT mounted on the Mach 1. Last night I finally got around to getting my polar alignment dialed it. I have been using a PoleMaster to get me pretty close, but wanted to see if I could further refine the alignment using PemPro 3 since I had recently paid for the upgrade. I started the PEMPro Alignment Wizard on the West side of the Meridian and did both the Azimuth and Altitude alignments several times until I got both under 1 arc min which was pretty much the limit of my Seeing last night. I then decided to switch to the East side of the Meridian and run the Polar Alignment Wizard again just to confirm I was aligned there as well. To my surprise I was off by quite a bit (3 - 5 arc mins) East of the meridian after letting the drift steps run for 3 - 5 mins. I didn't want to do any more adj ustments as it took me several hours to get it to within 1 arc min West of the meridian. I switched back to the West and ran the polar alignment wizard again for both Az and Alt and after 5 mins both were still under 1 arc min. When I got to the step of moving the star to the end of the pointed arrow I didn't have to do anything as they were both dead on the point of the arrow. All the PEMPro 3 settings I used for where to slew in the sky where left at there defaults. So my questions for the group is why would my polar alignment be different on one side of the meridian vs. the other? I thought once the mount is polar aligned it really should not matter which side of the Pier it is on. I have no idea why doing a pier flip to the other side of the meridian would cause such a big swing in the alignment. My only guess is that maybe my OTA is not sitting Orthogonal on the mount but I wouldn't think it would matter for drift alignment. The other thought I had is may be I need to adjust my balance to be slightly weights heavy. Currently it is almost perfectly balanced on both axis. The Mach 1 is only about a year and half old so would not expect there to be much backlash as it has the new self adjusting gear mesh mechanism. Needless to say, I am kind of stumped. I would welcome any knowledgeable advice on what might be going on here as I am not really sure what to do next. Thanks in advance for the helpful advice. Clear Skies, Andrew J
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Re: DEC delay in reversal
Roland Christen
You may have end play on the small worm. That is caused by the retaining nut being loose. If there is end play, you can feel it when you move the end of the telescope back and forth in the Dec direction. Try to gently move the scope back and forth with just finger pressure. If you feel a small amount of play at the end of the scope, you may have a loose bearing on the worm shaft.
toggle quoted messageShow quoted text
You can remove the end play by unscrewing the small round cover on the right side of the gearbox, you will see the retaining nut with 2 small holes which are used with a spanner wrench. Use a spanner to first back off the nut turning counterclockwise, then tighten turning clockwise until the bearing is fully seated and you feel no more motion at the end of your scope. Rolando
-----Original Message-----
From: Suresh Mohan Neelmegh drsureshmohan@... [ap-gto] To: ap-gto Sent: Sat, Mar 3, 2018 12:44 pm Subject: [ap-gto] DEC delay in reversal I’m getting a huge delay in reversal when I change direction, I opened the gear box to see where the delay is ; all the gears are working fine but the worm gear ( the huge one is taking time ; if i tighten a little on the harder side the motor is struggling. . What should I check ? Suresh ------------------------------------ Posted by: Suresh Mohan Neelmegh <drsureshmohan@...> ------------------------------------ To UNSUBSCRIBE, or for general information on the ap-gto list see http://groups.yahoo.com/group/ap-gto ------------------------------------ Yahoo Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/ap-gto/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/ap-gto/join (Yahoo! ID required) <*> To change settings via email: ap-gto-digest@... ap-gto-fullfeatured@... <*> To unsubscribe from this group, send an email to: ap-gto-unsubscribe@... <*> Your use of Yahoo Groups is subject to: https://info.yahoo.com/legal/us/yahoo/utos/terms/
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Re: APPM and Pinpoint
W Hilmo
I looked at the APPM log file, and it doesn’t have any additional information as to what happened with the plate solve. Actually, it considers the solve successful, which it was not (unless success is defined as “done”). Here is an excerpt:
--------------- 0000034 2018-03-03 09:06:18.360: Info, PinPoint Test Solve, File = C:\Users\wadeh\Desktop\Cone-1x1800-Ha.fit 0000035 2018-03-03 09:06:18.360: Info, PinPoint Test Solve, RA/Dec = 6.66811666666667 / 9.64386944444444 0000036 2018-03-03 09:06:18.360: Info, PinPoint Test Solve, Use FITS for Hints = True, X/Y Scale = 1.62 / 1.62 0000037 2018-03-03 09:06:18.360: Info, PinPoint Test Solve, AllSky = False 0000038 2018-03-03 09:06:18.360: Info, PinPoint Test Solve, Timeout = 120 0000039 2018-03-03 09:08:27.650: Info, PinPoint Test Solve, Solve Successful 0000040 2018-03-03 09:08:31.421: Exception, Plate Solving, User Clicked Cancel or Close --------------- Regarding a sample image, I don’t have a Dropbox account, but you can download a FITS file from https://www.faintfuzzy.net/2018/cone-1x1800-ha.fit. This is a wide field setup, so there are lots of stars. To solve it efficiently in Visual Pinpoint with USNO A2.0, I am using Min sigma of 8 and Max magnitude of 10. This one took 22 seconds when I tried it right now. My 2x2 binned images off the same system take about 5 or 6 seconds. Here is the output from Visual Pinpoint for this image and the above settings: --------------- Plate-solve run at 3/3/2018 11:07:45 AM Use File/Save As to save this file \\xxx\Cone-1x1800-Ha.fit: 3751 image stars found. (doing spiral search...) 172 catalog stars found. Solved using 50 of max 500, RMS residual is 0.50 arcsec, order =4 Solution took 22.8 seconds Centerpoint RA = 06h 41m 03.766s Dec = 09° 37' 25.91" Pointing error 0.3 arc minutes WCS: Roll = -0.48 HScale = -1.622 VScale = -1.623 PA = 0.485° FWHM = 6.39 arcsec ZeroPoint = 16.44 (1 sec.) --------------- Thanks, -Wade From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] Sent: Saturday, March 3, 2018 10:38 AM To: ap-gto@yahoogroups.com Subject: RE: [ap-gto] APPM and Pinpoint Is there any way to get either a more complete error message, or enable logging to get more details as to the progress of the attempt?Yes, you can look at the APPM log file. -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: <http://www.ccdware.com/> http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com <http://www.pulseguide.com/> Author of Sigma: http://www..gralak.com/sigma <http://www.gralak.com/sigma> From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] Sent: Saturday, March 3, 2018 9:49 AM To: ap-gto@yahoogroups.com Subject: [ap-gto] APPM and Pinpoint I am using APCC Pro (version 1.6.0.3) and have been using Pinpoint v6 as the plate solver for APPM. This has been working reasonably well for me with the GSC 1.1 catalog. Still, I do get some occasional plate solve failures, perhaps about 5% of the time. I have had it on my "to do" list for a while to switch to the USNO A2.0 catalog, and today is the day that I'm playing with it. The problem that I am having is that APPM's Image Link Test fails all attempts at solving with this catalog. Prior to testing with APPM, I worked with Visual Pinpoint to verify that the catalog works correctly. It is able to solve my test images in about 5 to 6 seconds. To get it working efficiently, I needed to tune the Min Sigma and Max Magnitude settings in Visual Pinpoint. < p>I have matched these settings in the Sigma Above Mean and Catalog Max Mag settings in APPM. I have also verified that the coordinates and image scale from the FITS headers are correct when Image Link Test reports them. The issue is that Image Link Test times out nearly 100% of the time on my test images. I bumped the Max Solve Time up to 120 seconds and it still times out. I have seen a couple of tests fail at about the 90 second point with an error that no stars were matched. Is there any way to get either a more complete error message, or enable logging to get more details as to the progress of the attempt? In particular, Visual Pinpoint reports the number of image stars detected and the number of catalog stars found on both failed and successful solves. This would be very valuable information in troubleshooting this. I'm also open to any other suggestions. Thanks, -Wade [Non-text portions of this message have been removed]
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PemPro Polar Alignment differs East to West
Andrew Jones
Hello Everyone. I am looking for some guidance. I have a Mach 1 on a permanent pier in an observatory that I am in the process of getting setup. I currently have a 11" EdgeHD SCT mounted on the Mach 1. Last night I finally got around to getting my polar alignment dialed it. I have been using a PoleMaster to get me pretty close, but wanted to see if I could further refine the alignment using PemPro 3 since I had recently paid for the upgrade.
I started the PEMPro Alignment Wizard on the West side of the Meridian and did both the Azimuth and Altitude alignments several times until I got both under 1 arc min which was pretty much the limit of my Seeing last night. I then decided to switch to the East side of the Meridian and run the Polar Alignment Wizard again just to confirm I was aligned there as well. To my surprise I was off by quite a bit (3 - 5 arc mins) East of the meridian after letting the drift steps run for 3 - 5 mins. I didn't want to do any more adjustments as it took me several hours to get it to within 1 arc min West of the meridian. I switched back to the West and ran the polar alignment wizard again for both Az and Alt and after 5 mins both were still under 1 arc min. When I got to the step of moving the star to the end of the pointed arrow I didn't have to do anything as they were both dead on the point of the arrow. All the PEMPro 3 settings I used for where to slew in the sky where left at there defaults. So my questions for the group is why would my polar alignment be different on one side of the meridian vs. the other? I thought once the mount is polar aligned it really should not matter which side of the Pier it is on. I have no idea why doing a pier flip to the other side of the meridian would cause such a big swing in the alignment. My only guess is that maybe my OTA is not sitting Orthogonal on the mount but I wouldn't think it would matter for drift alignment. The other thought I had is maybe I need to adjust my balance to be slightly weights heavy. Currently it is almost perfectly balanced on both axis. The Mach 1 is only about a year and half old so would not expect there to be much backlash as it has the new self adjusting gear mesh mechanism. Needless to say, I am kind of stumped. I would welcome any knowledgeable advice on what might be going on here as I am not really sure what to do next. Thanks in advance for the helpful advice. Clear Skies, Andrew J
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DEC delay in reversal
Suresh Mohan
I’m getting a huge delay in reversal when I change direction, I opened the gear box to see where the delay is ; all the gears are working fine but the worm gear ( the huge one is taking time ; if i tighten a little on the harder side the motor is struggling. . What should I check ?
Suresh
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Re: APPM and Pinpoint
Ray Gralak
> Is there any way to get either a more complete error message, or enable logging to get more details as to the progress of the attempt? Yes, you can look at the APPM log file.
-Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, March 3, 2018 9:49 AM To: ap-gto@... Subject: [ap-gto] APPM and Pinpoint
I am using APCC Pro (version 1.6.0.3) and have been using Pinpoint v6 as the plate solver for APPM. This has been working reasonably well for me with the GSC 1.1 catalog. Still, I do get some occasional plate solve failures, perhaps about 5% of the time. I have had it on my "to do" list for a while to switch to the USNO A2.0 catalog, and today is the day that I'm playing with it. The problem that I am having is that APPM's Image Link Test fails all attempts at solving with this catalog.
Prior to testing with APPM, I worked with Visual Pinpoint to verify that the catalog works correctly. It is able to solve my test images in about 5 to 6 seconds. To get it working efficiently, I needed to tune the Min Sigma and Max Magnitude settings in Visual Pinpoint.
< p>I have matched these settings in the Sigma Above Mean and Catalog Max Mag settings in APPM. I have also verified that the coordinates and image scale from the FITS headers are correct when Image Link Test reports them.
The issue is that Image Link Test times out nearly 100% of the time on my test images. I bumped the Max Solve Time up to 120 seconds and it still times out. I have seen a couple of tests fail at about the 90 second point with an error that no stars were matched.
Is there any way to get either a more complete error message, or enable logging to get more details as to the progress of the attempt? In particular, Visual Pinpoint reports the number of image stars detected and the number of catalog stars found on both failed and successful solves. This would be very valuable information in troubleshooting this.
I'm also open to any other suggestions.
Thanks, -Wade
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Re: APPM and Pinpoint
Ray Gralak
Hi Wade,
Can you zip some of the problem images and make them available via a dropbox link?
-Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, March 3, 2018 9:49 AM To: ap-gto@... Subject: [ap-gto] APPM and Pinpoint
I am using APCC Pro (version 1.6.0.3) and have been using Pinpoint v6 as the plate solver for APPM. This has been working reasonably well for me with the GSC 1.1 catalog. Still, I do get some occasional plate solve failures, perhaps about 5% of the time. I have had it on my "to do" list for a while to switch to the USNO A2.0 catalog, and today is the day that I'm playing with it. The problem that I am having is that APPM's Image Link Test fails all attempts at solving with this catalog.
Prior to testing with APPM, I worked with Visual Pinpoint to verify that the catalog works correctly. It is able to solve my test images in about 5 to 6 seconds. To get it working efficiently, I needed to tune the Min Sigma and Max Magnitude settings in Visual Pinpoint.
< p>I have matched these settings in the Sigma Above Mean and Catalog Max Mag settings in APPM. I have also verified that the coordinates and image scale from the FITS headers are correct when Image Link Test reports them.
The issue is that Image Link Test times out nearly 100% of the time on my test images. I bumped the Max Solve Time up to 120 seconds and it still times out. I have seen a couple of tests fail at about the 90 second point with an error that no stars were matched.
Is there any way to get either a more complete error message, or enable logging to get more details as to the progress of the attempt? In particular, Visual Pinpoint reports the number of image stars detected and the number of catalog stars found on both failed and successful solves. This would be very valuable information in troubleshooting this.
I'm also open to any other suggestions.
Thanks, -Wade
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APPM and Pinpoint
W Hilmo
I am using APCC Pro (version 1.6.0.3) and have been using Pinpoint v6 as the plate solver for APPM. This has been working reasonably well for me with the GSC 1.1 catalog. Still, I do get some occasional plate solve failures, perhaps about 5% of the time. I have had it on my "to do" list for a while to switch to the USNO A2.0 catalog, and today is the day that I'm playing with it. The problem that I am having is that APPM's Image Link Test fails all attempts at solving with this catalog. Prior to testing with APPM, I worked with Visual Pinpoint to verify that the catalog works correctly. It is able to solve my test images in about 5 to 6 seconds. To get it working efficiently, I needed to tune the Min Sigma and Max Magnitude settings in Visual Pinpoint. I have matched these settings in the Sigma Above Mean and Catalog Max Mag settings in APPM. I have also verified that the coordinates and image scale from the FITS headers are correct when Image Link Test reports them. The issue is that Image Link Test times out nearly 100% of the time on my test images. I bumped the Max Solve Time up to 120 seconds and it still times out. I have seen a couple of tests fail at about the 90 second point with an error that no stars were matched. Is there any way to get either a more complete error message, or enable logging to get more details as to the progress of the attempt? In particular, Visual Pinpoint reports the number of image stars detected and the number of catalog stars found on both failed and successful solves. This would be very valuable information in troubleshooting this. I'm also open to any other suggestions. Thanks, -Wade
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Re: A-P1100 Absolute Encoders installed by Astro-Physics?
Ray Gralak
Roland wrote:
Sure, you can do unguided imaging with a small refractor, even without absolute encoders. Just turn on PEM function,Roland makes a good point here that I didn't mention in my last post. You can usually get great results by just using PEM if you are using a short focal length refractor. Encoders will provide a more visible difference in a longer focal length scope. Still, it wouldn't hurt at all to use encoders with a short focal length scope. It's just that the bang for the buck isn't as great in that case. -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message-----
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Re: A-P1100 Absolute Encoders installed by Astro-Physics?
Ray Gralak
Hi Peter,
You wrote: Yes, I forgot about that. PEMPro works best with good to excellent seeing condition and I don't want to deal with that.Just a clarification here... PEMPro's PEC creation will work well even in poor seeing conditions. In fact it's because PEMPro can "see through" the effects of random or consistent poor seeing conditions that you would want to use PEMPro to create a smooth and accurate PEC curve over other PEC creation mechanisms. That said, using high resolution absolute encoders like you can get for the AP1100/1600/3600 is a superior solution. They will not only correct periodic error but also non-periodic error caused by random variations in the worm wheel teeth on other factors. Encoders are definitely the way to go if you can afford them. Best regards, -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message-----
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Re: Encoder assembly video
Gregory <fyrframe@...>
Will this help? http://www.tucows.com/preview/300544/Video-Edit-Magic?q=video++%22Video+Editing%22 Gregory
On 3/2/2018 3:17 PM, chris1011@...
[ap-gto] wrote:
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Re: A-P1100 Absolute Encoders installed by Astro-Physics?
Roland Christen
I thought the whole purpose of absolute encoders is to allow long exposures unguided with no periodic error. There is no periodic error. That allows unguided imaging as long as you have no drift in either axis. However, practically speaking there can always be some drift due to things not under the mount's control such as:
1) tube flexure or optical axis flex in the scope or imaging train 2) Polar misalignment 3) atmospheric refraction 4) other effects like mirror flop Some of these things can be minimized, but others are inherent. Example, #3 - atmospheric refraction causes different tracking rates in different parts of the sky, not only in RA but also in Dec, AND is not a fixed amount but varies with atmospheric temperature and pressure. Unguided imaging is possible with encoders because it eliminates the largest variable, the mount's periodic error. It also enables a modeling program to set the delta tracking rates in both axes to a very fine resolution in order to counter all the other variables. Sure, you can do unguided imaging with a small refractor, even without absolute encoders. Just turn on PEM function, drift align on the pole (or use pole scope, electronic pole finder etc) and fire away. When you have a 3 arc sec per pixel imaging scale, you won't notice small drift errors. Once you go above about 500mm with a good sharp optical system you better control your star motions to the sub-arc sec level. And you cannot do that with just good polar alignment alone. Rolando -----Original Message-----
From: axnyslie@... [ap-gto] To: ap-gto Sent: Fri, Mar 2, 2018 8:16 pm Subject: [ap-gto] Re: A-P1100 Absolute Encoders installed by Astro-Physics? I thought the whole purpose of absolute encoders is to allow long exposures unguided with no periodic error. Seems like a pricey upgrade if you still have to implement a guidescope or OAG in the imaging process. Joe
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Re: A-P1100 Absolute Encoders installed by Astro-Physics?
axnyslie@...
I thought the whole purpose of absolute encoders is to allow long exposures unguided with no periodic error. Seems like a pricey upgrade if you still have to implement a guidescope or OAG in the imaging process.
Joe
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Re: A-P1100 Absolute Encoders installed by Astro-Physics?
Roland Christen
Weight is less than 1 lb. per axis.
toggle quoted messageShow quoted text
Rolando
-----Original Message-----
From: pnagy@... [ap-gto] To: ap-gto Sent: Fri, Mar 2, 2018 7:49 pm Subject: Re: [ap-gto] A-P1100 Absolute Encoders installed by Astro-Physics? Rolando, Another question about AE. What is the total weight of AE Kit for A-P1100 mount? My setup is always portable and I carry the whole RA/Dec assembly (minus counterweight shaft) from inside of my house to backyard (very short trip). I hope AE does not add too much weight to my A-P1100 mount. Peter ---In ap-gto@..., wrote : Hi Rolando,
I live in Reno, NV and temperature can drop to as low as about 10F (-14C) and temperature is normally warmer than 20F (4C). I usually don't image if the forecast gets colder than 20F (4C) or if the dew point falls below ambient temperature. Reno is generally pretty dry so I don't have electric dew shield. Anyway which temperature version AE do you recommend for my area: Standard or Extended? I see the spec at your web site: RESOLU TE Absolute Encoder: Operating: 0 degrees C to +80 degrees C (32 F to +176 F) Storage: -20 degrees C to +80 degrees C (-4 F to +176 F) RESOLUTE ETR (Extended Temperature Range) Encoder: Operating: -40 degrees C to +80 degrees C (-40 F to +176 F)< Storage: -40 degrees C to +80 degrees C (-40 F to +176 F) Thanks,
Peter
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Re: Encoder assembly video
topboxman
Hi Rolando,
Take your time. Peter
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