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Re: Things that customers do that drive me nuts on CN
Bill Long
AP has a wonderful tutorial on how to use PEMPro to generate a new curve. I have personally walked a good dozen imagers through it. Well worth the effort. Just know that you need to increase your RA MinMo 😉
From: ap-gto@... <ap-gto@...> on behalf of mogollonobs@... [ap-gto] <ap-gto@...>
Sent: Tuesday, July 10, 2018 6:36 PM To: ap-gto@... Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN Steve, It's a 12-year old mount that's probably never been serviced or adjusted as far as you know. How old is the PEC curve? What was it if it's recent? I apologize if you've posted this somewhere else, I'm not chasing it down.
Personally, if this is the case I would tear it apart, check the gears, re-grease it, reset the mesh, and run a new curve before I blamed stiction or PHd2. If you don't want to do this then send it back and let AP do it.
Keith
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Re: Things that customers do that drive me nuts on CN
Stephen Winston
Hi Keith,
I actually just reprogrammed the PEC curve as I had recently upgraded from L to the V2 chip. Per PEMPro it went from about 7.8 arc-seconds peek-2-peek to a reported 0.5 arc-second peek-to-peek. So I'm a bit hesitant to mess with RA ;). Tearing down DEC is definitely something I will do. I'll have to think a bit more about messing with RA :) Steve
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Re: Things that customers do that drive me nuts on CN
mogollonobs
Steve,
It's a 12-year old mount that's probably never been serviced or adjusted as far as you know. How old is the PEC curve? What was it if it's recent? I apologize if you've posted this somewhere else, I'm not chasing it down. Personally, if this is the case I would tear it apart, check the gears, re-grease it, reset the mesh, and run a new curve before I blamed stiction or PHd2. If you don't want to do this then send it back and let AP do it. Keith
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Re: Things that customers do that drive me nuts on CN
Bill Long
And in AP's defense they have been making and using these mounts, for quite literally decades. Its awfully nice of Roland to come on here and tell us mortals how to guide their mounts. They even went as far as to take the time to learn PHD2 (since he uses MaximDL) so they could provide even better advice. Strongly suggest you heed it. :)
From: ap-gto@... on behalf of stephenjwinston@... [ap-gto]
Sent: Tuesday, July 10, 2018 2:02 PM To: ap-gto@... Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN In my (partial :) defense, I have been using 0.20 MinMove on DEC literally for years while imaging on the West side of the mount, and I had never seen this oscillation pattern and my images were just fine. As I was imaging manually (sitting by the scope) I would generally go a max of one hour beyond the meridian before changing targets.
It's only when I recently started automating via SGP and extending my imaging runs to include an automated meridian flip that I started seeing this problem.
Anyway - I'll report back tomorrow on how M8 or M16 behave - fingers crossed :)
Steve
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Re: Mach 1 Software
Not to mention that Norton thinks the Prism forum web site is dangerous:
toggle quoted messageShow quoted text
https://safeweb.norton.com/report/show?url=http:%2F%2Fwww.prism-astro.com%2Fforum_us%2Findex.php -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro V3: https://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver
-----Original Message-----
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Re: Things that customers do that drive me nuts on CN
Stephen Winston
Hi Roland,
Thanks for the suggestions. I have already being doing a variant of re-positioning the DEC wheel. At the end of each imaging run I have SGP park the scope in position #3. For the next evening's imaging session I loosen the clutches and manually move the mount to park #1, re-tighten the clutches, power up and do a star sync to get going. I would say over the last couple of weeks that I have moved both the DEC and RA worm positions through a wide range of different starting positions. I have also already removed the DEC motor cover and verified I can move the cogs easily by hand. In fact I actually stopped tracking at a point where I was seeing the oscillation, disconnected the motors cable, and verified I could move the gears, and I couldn't detect and tight spot. I will do as you suggest and do a full "overhaul" on the DEC worm/wheel. I've never actually re-greased the worm or wheel (I bought the mount second hand several years back and it's originally from 2006). And I will do a re-mesh. I'll report back later on whether that helps. thanks! Steve
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Re: CP4 & Potential Clashing with Observatory networks;
Eric Dreher
Er...what reply?
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CP4 & Potential Clashing with Observatory networks;
Joe Zeglinski
Hi,
This is NOT an ad, but I was very impressed trying out
this WiFi tool. Nor do I want to suggest that a CP4 might be overly affected to
any great extent. but if WiFi “stuff happens”, you might want to give this
free tool a look-see :-)
Occasionally I see posts about a CP4 having network
connection issues, beyond the usual APCC configuration issues that sometimes
crop up, and thought I would investigate the possibilities of our high
tech accessories causing THEMSELVES some mutual confusion – or even by a
neighbour’s 2G or (less likely 5G) network AP’s - (that’s ... “ACCESS
POINTS”, such as modems and routers).
I posed the question as to how
close could AP network devices be to each other.
For example, if you use a Router in your observatory ... and also have
something like a CP4 (another network access point), can there be a signal
mix-up or even failure to connect.
Mr. Casey Cathey (MetaGeek Support), representing a company designing
Network Analysis & Display software (Windows, Mac OS, and Android)
emailed me back the following reply:
***************************************************************************************
**************************************************************************************************** Based on this advice, it would seem prudent not to put Routers in most dome or roll-off observatories under 30 feet in diameter, since things could deteriorate with the Router against a far wall, and a CP4 (an AP device itself) on the mount in the centre of the building. However, perhaps that is a marginal situation since many have such amateur observatories, and yet there aren’t problems with network connection to the CP4. But, that is something to consider. MetaGeeks has some interesting network mapping programs,
(originally “Shareware”), but recent versions are priced for Commercial use by
“Network Analysts” who can write them off as a business expense. They even have
a USB-attached antenna dongle to perform “Spectral Analysis and Display” of
interfering radio waves overlapping normal 2.4 GHZ and 5.8 GHZ WiFi bands. You
can see the grass noise from a microwave oven overlap your PC WiFi channel. In
such case, move to a far lower frequency (channel #1 or #11 ... or leave 2G and
go 5G). I
downloaded the (final free 3.1 version) of “InSSIDer HOME” which graphically
displays all 11 Channels in use by neighbours around the block. (The product is
an acronym for In-SSID-er), for the network term SSID. Most WiFi are weak signals, but you never know about those sporadic spikes I sometimes see shooting out from a standard BELL or ROGERS (HiTRON model) modem/router. One neighbour’s signal jumped to –5 DBM strength for a few minutes, luckily not on MY Channel. That was a shocker. So, this software is useful to us, in assigning our Router 2.4 GHZ channel to avoid “Co-channels, and Overlap channels). Ideally use Channel (1, 6, or 11), which do NOT overlap each other. MegaGeeks website has some excellent Educational article pages on this matter. I really like using InSSIDer.exe HOME ver. 3.1 (for Win-XP/7/8/10, or MAC OS) on my laptop, walking around with it to spot peaks & its signal strength values of 2G networks in the area around the scope, or around the house. That was not only an education in the pitfalls or choosing a 2.4 GHZ channel, but also an eye-opener of what is going on in the invisible wireless world. Besides it is loads of fun to use, a real hoot ! If
you want to try it free, and learn something about your wireless
environment at home, or the observatory, get a shareware download of any
of the 2016 (last free release year) programs – Choose from (Win, MacOS, or
ANDROID phone) in their pull-down list. I enjoyed using both the Windows,
and the ANDROID smartphone versions.
Sorry, no I-PHONE version, and the ANDROID app was (unfortunately) discontinued
by MetaGeeks in 2017. Only the “original free” ANDROID download is still
(tenuously) available, if you visit the link above. Things that affect WiFi in the house (or our observing
spot), are listed in the LESSON Tab material of InSSIDer app
– I was surprised by a few of these, which I hadn’t considered before.
It is probably a “short list”.
How many times has a neighbour’s wireless analog
security camera hit the observatory?
– Even worse if the camera is on a motorized pan & tilt mount,
on a periodic scan cycle.
Just thought some might be interested in further
investigating local WiFi interference.
Hope this helps,
Joe Z.
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Re: Things that customers do that drive me nuts on CN
Roland Christen
What you might wan to try is to send the mount to Park2 and shut off power. Park 2 will send the scope pointing due east.
Now loosen the clutches and point the scope to the Park3 position and tighten the clutches again.
Turn power back on and Resume From Park3. When you have done that, you will in effect be on a new portion of the gearwheel, basically 90 degrees from where you were before.
It may be that you had a high spot on one side of the gearwheel and a low spot on the other due to the way you were always using the mount only on one side. It may have worn the wheel more on one side versus the other. Moving the mount by 90 degrees this way every 3 - 4 months will even out the wear on the wheel.
If you have a non-spring loaded gearbox, take a bit of time and re-mesh the worm gear to the worm wheel. It's easy to do, basically loosen and then tighten two screws - it's explained on our website. If you have a spring loaded gearbox, then a simple re-setting of the backstop is all you need to do.
You might also want to check the spur gear backlash clearance by feeling the amount of motion that the motor gear moves back and forth while holding the output gear steady. Two teeth movement on the motor gear is ideal, but no more than that. The spur gears should turn freely without any lumpy spots for their full rotation.
Rolando
-----Original Message-----
From: stephenjwinston@... [ap-gto] To: ap-gto Sent: Tue, Jul 10, 2018 4:03 pm Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN In my (partial :) defense, I have been using 0.20 MinMove on DEC literally for years while imaging on the West side of the mount, and I had never seen this oscillation pattern and my images were just fine. As I was imaging manually (sitting by the scope) I would generally go a max of one hour beyond the meridian before changing targets.
It's only when I recently started automating via SGP and extending my imaging runs to include an automated meridian flip that I started seeing this problem.
Anyway - I'll report back tomorrow on how M8 or M16 behave - fingers crossed :)
Steve
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Re: Mach 1 Software
Bill Long
I tried out PRISM and it just has way too much stuff going on for me to want to use it for streamlined imaging. SkyX has been good so far, I just wish they put in some meridian flipping code.
From: ap-gto@... on behalf of Ron Kramer ronkramer1957@... [ap-gto]
Sent: Tuesday, July 10, 2018 8:27 AM To: ap-gto@... Subject: Re: [ap-gto] Mach 1 Software I've not gotten that deep into it. I'm still trying to work out kinks. The manual (being a translation from French is less than detailed). But the program keeps forcing me to come back and work with it again.
I run APCC in the background. I have PemPro but have not really had a chance to use it after a couple of failed attempts. I settled for ascoms "record PEC" and playback and I see the sine wave is gone from my guiding. I've been living with that as I've
been dealing with other issues. (Dome rotator and shutter firmware updates and working with the author on that) Finally working well. I sold a 127mm and replaced with 152mm scope and now dealing with trying to land an adapter to install a FT and EF to the
new tube. Wrong one set, new one on the way - I may be up again after months of down time next week.
Prism is freaking amazing. But I don't have it under control yet. I've reverted back to SGP for real imaging - until I get Prism fully working. For many it may work out of the gate, I have a... complex?
setup in that I'm fully remote and Still have some kinks (some issues with dome graphic and mount graphic displaying properly with poth, which I had to add for a dome hub). If I use a virtual com port on APCC for the dome com port (will it hub a 2nd connection?).
I then have issues with the lodestar X2 connection. It works, but I get a interlaced image each star as 2 points. (others do not have this issue) and I don't have the interlaced image with this camera and
driver in PHD2. ???!!!
What keeps me from tossing it aside is I have 60 more days of trial and the I have working is amazing. Once the scope is setup with focuser I can delve into focusing features and Hamzat said he'd timeview
into my setup and
check my PRism configuration. I WANT TO USE IT. But time will tell.
On the other hand I love WWT for goto's. No other program shows actual full sky surveys. I wanted to do some test the other day and IC5070 is just below my tree line. Using WWT I could see other areas of interest above the tree line and did some sweet image of the outer fringes that I felt were more interesting than the Pelican itself. Only because in WWT I could see them and click on the spot and the mach1 nailed it. (as it always does). I've found no need for a pointing model. HOWEVER I am now only at 1210 fl and that may be very different for those in the 2000+ focal length area. Biggest problem with Prism is (few if anyone use it in the U.S.) so it's hard to get experienced help. From what I've heard it's extremely popular in Europe. In use for over 10 years.
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Re: Things that customers do that drive me nuts on CN
Stephen Winston
In my (partial :) defense, I have been using 0.20 MinMove on DEC literally for years while imaging on the West side of the mount, and I had never seen this oscillation pattern and my images were just fine.
As I was imaging manually (sitting by the scope) I would generally go a max of one hour beyond the meridian before changing targets. It's only when I recently started automating via SGP and extending my imaging runs to include an automated meridian flip that I started seeing this problem. Anyway - I'll report back tomorrow on how M8 or M16 behave - fingers crossed :) Steve
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Re: Things that customers do that drive me nuts on CN
Bill Long
Good to hear.
Throughout this, it sounded like you were equating low MinMo values to better images. Not sure if you were actually intending to do that, but its most certainly not the case. Getting the correct guiding parameters set should allow you to get the best images your seeing will allow for.
From: ap-gto@... on behalf of stephenjwinston@... [ap-gto]
Sent: Tuesday, July 10, 2018 1:14 PM To: ap-gto@... Subject: RE: [ap-gto] Re: Things that customers do that drive me nuts on CN An update from last night's imaging run - and it's good news :) I gathered some more data on NGC7000, including doing an automated meridian flip using SGP. The guide settings matched a lot of what has been recommended here: 2s exposures and
MinMove of 0.40 on DEC. The results look pretty good :)
One caveat being that imaging NGC7000 is basically straight up from my location when it crosses the meridian, and that has been my least problematic orientation for the mount. I'll be
repeating those guide settings tonight on M16 or M8 to see if it also has the same positive result.
Steve
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Re: Things that customers do that drive me nuts on CN
Stephen Winston
An update from last night's imaging run - and it's good news :)
I gathered some more data on NGC7000, including doing an automated meridian flip using SGP. The guide settings matched a lot of what has been recommended here: 2s exposures and MinMove of 0.40 on DEC. The results look pretty good :) One caveat being that imaging NGC7000 is basically straight up from my location when it crosses the meridian, and that has been my least problematic orientation for the mount. I'll be repeating those guide settings tonight on M16 or M8 to see if it also has the same positive result. Steve
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Re: Things that customers do that drive me nuts on CN
If this group was easier to use, easier to read, didn't repeat everything over and over and over and over... included attachments. People wouldn't need places like cloudynights. Forums are VERY EASY to install in your website. Most are free. Very easy to install. I believe nexdome (who are not web savvy) just installed one from wordpress. With AP's reputation of being the best of the best in everything they do, I'm surprised you settle for this yahoo group crap.
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Re: Mach 1 Software
C. E. Steuart Dewar <cesdewar@...>
I installed a Rayox saddle on my mount and yes, it works beautifully and I find it a huge improvement in confidently mounting my C-11 Edge. Previously, especially in the dark, I was always concerned that I had the rail properly grabbed by the mount. It’s expensive, yes, but dropping a scope is a lot more expensive ;)
Regards, CESDewar From: ap-gto@... <ap-gto@...> Sent: Thursday, July 5, 2018 3:18 PM To: ap-gto@... Subject: [ap-gto] Mach 1 Software Hi All, I will be receiving my mount soon but will be waiting on my OTA for a few months (FSQ106). So I am piecing together all the parts that I will be needing in the mean time. I would like to tap the people experienced with using the mounts to make sure I am efficient in my spending and am set up for minimal problems: 1. I am planning on a Rayox saddle. Just making sure it works well with the mount? 2. The software part is where I get a tad confused. George was super helpful explaining the ASCOM requirement for the mount and some of the other items. But where I got a little lost was needing a separate software for the camera (MaximDL?) and something to guide through the computer like SkyX. Any input on warts those might have or if there is something else recommended as well as any other software. I already have PS and am pretty good with using it for my bird photography. Also, what would 'synch' them all up so they work together? 3. I am getting the camera a little later after I get everything else set up. So I can get the fittings correct and the focuser & filer wheel later in the year.. I know the sensors I would prefer so I have narrowed the camera down quite a bit. Thanks for helping out a noob. Jon Swanson [Non-text portions of this message have been removed]
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Re: Things that customers do that drive me nuts on CN
Stephen Winston
Thanks Ray - really looking forward to your interpretation of the logs.
Let me know if you need any additional data - I still have the ascom logs from my previous nights testing / older PHD2 logs. I didn't include them in the zip as they are not relevant to the PHD log I gave you. And at the risk of beating a dead horse :), I think the problem breaks down into two parts: 1 : What triggers the DEC excursion in the first place. Based on all the great info from Roland & Co, this can likely be eliminated by using more reasonable MinMove settings. 2 : Why the excursion spikes and then takes so long to be corrected (usually 15-30 seconds) My interpretation of the graph (several corrective pulses over multiple seconds with no response, followed by a sudden swing and over correction) is that it looks like stiction. As the full swing happens over such a long time period (30+ seconds), I don't think it can be described as a "fast" oscillation. But I could be wrong - maybe I just need to re-calibrate my definition of fast :). My concern is that I may be able to avoid this issue with less aggressive MinMove settings using my current short-focal length / large imaging scale set-up (which is pretty forgiving). But when I switch to a more demanding / longer focal length set-up the issue may return. So, I'd really like to understand both parts of the problem - the initial trigger and the mounts (lack of) response to corrective pulses. Steve
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APPM --- strange point values in a model
Dmitri
Hello, I ran APPM for the first time. Over all there were 47 points and all were plate solved just fine. The differences between assumed RA,DEC and what plate solving showed were in [-15,15] arc-min for all but one point. Which showed the differences -5263 arc-min in RA and 2706 arc-min in DEC. Looking at pairs coordinates they should be about 1 arc-min and 6 arc-min (below is part of APPM log corresponding to this point). Such big reported differences look like an error. I am wondering if this point will adversely affect the pointing model. Should I just remove the point from the model? Is this a bug in APPM that affects modeling or it affects only visual presentation of mapped points? ========================================================================== 0000972 2018-07-09 23:03:56.922: Info, SlewNext, Starting Slew to Point 22 0000973 2018-07-09 23:03:56.927: Info, Slew Next, East=False, Dec=45, HA=1.5084944665313, MerDelay=0.25, MerOffset=0 0000974 2018-07-09 23:03:57.020: Info, State Machine, Entering State=PreSlewing 0000975 2018-07-09 23:04:02.453: Info, State Machine, Entering State=Slewing 0000976 2018-07-09 23:04:02.706: Info, State Machine, Entering State=StartSettle 0000977 2018-07-09 23:04:02.745: Info, StartSettle, Starting Settle wait time 0000978 2018-07-09 23:04:02.955: Info, State Machine, Entering State=WaitSettle 0000979 2018-07-09 23:04:07.955: Info, StartSettle, Settling Time Complete 0000980 2018-07-09 23:04:08.206: Info, State Machine, Entering State=StartImage 0000981 2018-07-09 23:04:08.249: Info, State Machine, Starting Exposure, Duration=10, LST=17.2351916666667 0000982 2018-07-09 23:04:08.249: Info, State Machine, LST Mid Image=17.2367194444444 0000983 2018-07-09 23:04:08.249: Info, StartTakeImage, Sequence Generator Pro: Binning=1, Duration=10, IsDarkFrame=False 0000984 2018-07-09 23:04:18.455: Info, State Machine, Entering State=WaitImage 0000985 2018-07-09 23:04:18.532: Info, State Machine, Exposure Done. Saving to: C:\Users\Dmitri\Documents\Astro-Physics\APPM\Image-APPM-2018-07-09-222429.txt-0022-RA_15.724-DEC_45.000.fit 0000986 2018-07-09 23:04:22.007: Info, State Machine, Entering State=PlateSolveStart 0000987 2018-07-09 23:04:22.070: Info, State Machine, Starting Platesolve via SGPro PlateSolver: Scope RA,Dec= 15h 43m 24.9s( 15.72358), 45° 00' 00"( 45.00000) 0000988 2018-07-09 23:04:22.203: Info, State Machine, Entering State=PlateSolveWait 0000989 2018-07-09 23:04:33.287: Info, State Machine, Solved RA,Dec= 15h 42m 49.6s( 15.71378), 45° 06' 26"( 45.10722) 0000990 2018-07-09 23:04:33.287: Info, State Machine, Solved Image Scale X,Y=1.26891976731497, 1.26891976731497 0000991 2018-07-09 23:04:33.287: Info, State Machine, Iteration,Measurement,HA,RA,Dec= 0, 21, 8.2862215206667, -5263.442 arc-min, 2706.433 arc-min 0000992 2018-07-09 23:04:33.411: Info, ModelFile, 636B 0| 45.000000| 1.508494|0|0| 0.000000| 0.000000|1| 15.713778| 45.107217| 0.000000| 8.286222| 0001-01-01T00:00:00| 0.0| 0.0|0| 0.0|0| 0|0| 0||C:\Users\Dmitri\Documents\Astro-Physics\APPM\Image-APPM-2018-07-09-222429.txt-0022-RA_15.724-DEC_45.000.fit
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Re: Things that customers do that drive me nuts on CN
Roland Christen
And this is where the PHD's recommendation greatly differs. It is much more aggressive. In my case it recommended a 0.20 px (0.6 arc seconds) MinMove with a reported peak DEC error of 3.71 arc seconds. That peak error may be +- error or Peak to Peak. If that's the case, divide it by 2 to get the peak error. Then multiply it by 0.6 to get 1.1 arc sec or 0.37 pixels (or multiply by 0.8 to get 0.5 pixel MinMove).
Rolando
-----Original Message-----
From: stephenjwinston@... [ap-gto] To: ap-gto Sent: Tue, Jul 10, 2018 11:23 am Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN >That is why I recommend using a short unguided Dec graph to determine the actual atmospheric motion peak value.
Yep. And that is exactly what PHD2 Guiding Assistant is doing (measuring seeing with DEC guiding disabled).
>Then set the MinMove to between 60 and 80% of that value.
And this is where the PHD's recommendation greatly differs. It is much more aggressive. In my case it recommended a 0.20 px (0.6 arc seconds) MinMove with a reported peak DEC error of 3.71
arc seconds.
Using your 60% rule would put my MinMove at 60% of 3.71 arc-s, or 0.75 px, instead of the 0.20 px PHD recommended. I would say that 0.75 px is probably too pessimistic and something in the 0.30-0.40 range is probably more reasonable.
>I don't know how much more clear I can make this.
What you are saying is fully understood :).
As I previously mentioned to Bill and Wade, one of the outcomes of this will hopefully to get PHD2 to make more reasonable recommendations based on the Guiding Assistants measurements.
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Re: Things that customers do that drive me nuts on CN
Stephen Winston
>That is why I recommend using a short unguided Dec graph to determine the actual atmospheric motion peak value. Yep. And that is exactly what PHD2 Guiding Assistant is doing (measuring seeing with DEC guiding disabled). >Then set the MinMove to between 60 and 80% of that value. And this is where the PHD's recommendation greatly differs. It is much more aggressive. In my case it recommended a 0.20 px (0.6 arc seconds) MinMove with a reported peak DEC error of 3.71 arc seconds. Using your 60% rule would put my MinMove at 60% of 3.71 arc-s, or 0.75 px, instead of the 0.20 px PHD recommended. I would say that 0.75 px is probably too pessimistic and something in the 0.30-0.40 range is probably more reasonable. >I don't know how much more clear I can make this. What you are saying is fully understood :). As I previously mentioned to Bill and Wade, one of the outcomes of this will hopefully to get PHD2 to make more reasonable recommendations based on the Guiding Assistants measurements.
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Re: Things that customers do that drive me nuts on CN
Roland Christen
That is why I recommend using a short unguided Dec graph to determine the actual atmospheric motion peak value. Then set the MinMove to between 60 and 80% of that value. If the star motion is +-2 arc seconds peak to peak, then set the Min Move to 1.6 arc sec (or 0.48 pixels for a 3 arc sec per pixel scale). I don't know how much more clear I can make this.
If you set the MinMove to less than this value, you can guarantee you will have oscillations caused by guider chasing the seeing. Remember, you are trying to re-position a mechanical gear wheel by a few nanometers even at 1.6 arc seconds.
All we're trying to do in guiding Dec is to set a boundary within which we allow the star to bobble back and forth unimpeded. If it exceeds the boundary we want to nudge it gently back towards zero. We do NOT want to set up small rapid oscillations back and forth which can get out of hand.
Rolando
-----Original Message-----
From: stephenjwinston@... [ap-gto] To: ap-gto Sent: Tue, Jul 10, 2018 10:25 am Subject: Re: [ap-gto] Re: Things that customers do that drive me nuts on CN >You say that you have seen peak Dec errors of 3.71 arc seconds. Well the fact is that this error happened in the past and the next measurement may show a different position of the star,
Again, to try clarify: The 3.71 arc seconds error is what PHD2 Guiding Assistant measured as the Peak Error while calibrating with DEC tracking disabled.
Bill had suggested that users should us the Peak Error from PHD GA to set MinMo.
I was just making the point that the GA measured Peak Error is not necessarily the right metric to set MinMo - in my case it would mean setting MinMo to 1.25 px
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