PHD Guiding...star does not move enough.

[xelasnave]

I built a dark library.
I get a message after calibrating that it failed and that "star does not move enough" and suggestion for scope location. + or - 20 degrees I gather from celestial equator.
Well I have tried all over ..maybe it's finding a hot pixie but I did select manually to hopefully eliminate to possibility.
Any ideas on what I am doing wrong...now the mount was tracking but somewhat poorly so the star was moving...I think the focus is as good as I can get...in the end I tucked the don't ask again box and gave up.
Anyways it's annoying I resolved to auto guide tonight but I am now taking 60 sec exposures to get something...it seems a decent night but maybe be there is something up there causing this issue.
Any help will be greatly appreciated.
Alex

[Imme]

Try increasing step size Alex.

It’s in the brain tab from memory

[The_bluester]

Did you set it up with the wizard to begin with? If you follow that through step by step (Including the focal length of the guider) it should pre-populate most settings reasonably well, including the caibration step size.

If you bring up the manual guide dialog and set a long guide pulse amount (like 1000ms) does the star move in all directions when you hit the manual guide buttons? Just to make sure PHD2 is actually able to move the mount.

[Startrek]

Alex
Maybe check the items below
Select Brain then the “Guiding tab”
Increase search region to 15 pixels
Tick Star Mass Detection and set Tolerance to 60
Under Calibration make sure your focal length is set correctly for your guide scope not main scope focal length

For your Calibration select a star within 10 deg of the celestial equator and with 1 hour of the north meridian on the east side

Set your guide camera exposure to 2 seconds, it’s a good starting point

Also the PHD2 manual is a great guide ( under Contents ) I read it a few times and it helped me sort out some gremlins

Good luck
Martin

[xelasnave]

Thanks everyone I really appreciate your help.
Step size was out..focal length was wrong how that happened I have no idea..anyways playing with it whilst capturing was causing dropped frames so I will finish my run and try again...I need to move the scope as suggested for a start as my object is not in the right place for calibration.
On the positive I have stars on the screen..It was not working earlier due to a corrupted dark file and man it took ages to find it, but after I deleted that file the camera worked and it at least went thru calibration routine...I feel it will work when I try it with correct focal length, this was set last time out but why I entered a fl double reality is beyond me...damn cold ..it's down to 4 C ...not far off I feel...I will finish my run at 12 and have another go if I don't freeze to death.
Thanks again.
Alex

[xelasnave]

OK three quarter frozen but it is working and I am very happy. I have no idea why I had the focal length double what it should have been..also and luckily I had the sense to check for few on the guide scope..it was drowning ..that would have sent me bats if I had not noticed. The graph is not so hot but I am not worried my polar alignment needs checking as I tightened the pier bolts today which would possibly thrown the lignement out...anyways I took a three minute of a region of sky and the stars were good enough for me...trying ten minutes now just for fun.
Alex

[Startrek]

Alex
That’s great news getting your PHD2 Guiding up and running !!!
I may have sent you this before but I’ll send it again , here’s some tips for PHD2 to assist or improve your guiding

PHD2 Set Up and Guiding tips

1/ Try to Polar align to around 1arc minute error on Alt and Az

2/ “Auto select guide star” (recommended by PHD2) or manually select star that’s not too bright or saturated to avoid lost stars

3/ If guiding is poor ( above 2 arc seconds ) utilise the Guiding Assistant

4/ Check and adjust focus of your guide scope and camera to minimise lost stars

5/ Set your guide camera exposure time between 2 and 4 seconds ( Looping ) 2 seconds is a good starting point

6/ The SNR value of the guide star should be between 15.0 and 40.0 to avoid losing the guide star

7/ Don’t over correct settings , under correcting will let you manage your guiding performance better

8/ If Guiding is poor try and keep your min mo above 0.25 in RA and DEC . Don’t go above 0.6. A good starting point for min mo is 0.20 or 0.25

9/ Important- Build a Dark Frame library and a Bad pixel map to provide good calibration and stable guide star. PHD2 will only allow you to use one or the other

10/ The RA Osc value should be between 0.3 to 0.5
If it drops to 0.1 or lower then increase the RA aggressiveness or decrease the hysteresis
If it gets quite high say 0.8 then reduce the RA aggressiveness or increase the hysteresis

11/ Use Ascom Guiding - Laptop direct connect to mount ( preferred by PHD2 Developers) in lieu of ST4 connected guiding via camera to mount

12/ USB 2 cable to camera is not to exceed 5 metres

13/ Try and avoid cabling through a hub even a Powered hub, direct connect to the computer , you will have less issues

14/ Ensure you have the latest driver installed for your guide camera

15/ If guide camera is USB2 make sure you connect into a USB2 port with USB2 cable
If the guide camera is USB3 it most probably will connect with a USB2 cable

16/ Ensure you enter all the correct data for your guide camera into PHD2 brain tabs

17/ Make sure you get good Calibration. Calibrate within 10deg of celestial equator and within an hour of meridian
Once Calibrated save it and reuse it ( go to Brain in guiding tab and tick box “Auto restore Calibration”)

18/ if you lose guide star often , go to Brain in guiding tab and increase “Search region” and increase “ Star mass detection”


PHD2 Extra Guiding Tips
1/Try and keep your min mo in RA and Dec just above your arc sec error in both axis or leave as default (0.20) and see how the guiding performs over a few minutes
2/ Only make small adjustments in RA and Dec Aggressiveness. Wait for guiding to run for a few minutes to see any change or improvements
3/ If guiding is saw toothing in RA ( blue ) badly you maybe over correcting , reduce RA Aggressiveness and increase Min mo in RA only
4/ If guiding is saw toothing badly in DEC (red) then you could be over correcting, reduce DEC Aggressiveness and increase Min Mo in DEC
5/ If DEC ( red ) is staying for the most part above or below the centre line you are under correcting , so increase DEC Aggressiveness a bit and reduce Min mo
6/ If RA (blue) is receiving 2 or more consecutive pulses to correct it , then RA Aggressiveness is to low so increase by 5 at a time over a while to monitor its performance
7/ A random big spike in RA ( blue ) could be caused by many things like cable snag or drag , gust of wind , slight bump of the tripod , loose equipment or lost Guide Star
8/ A big random downward spike in DEC (red) can be caused by a “dither” command from your capture software through PHD2 , but you should see the word “dither” above the spike area on the PHD2 graph
9/ If guiding is still bad , go to the Brain and change the Guiding Algorithm from Hysterisis to “Predictive PEC”
It usually takes 20minutes of guiding on this algorithm to run 2 worm cycles of the mount and allow PEC training of the mounts performance. Sometimes the mount performs better using this PEC algorithm
10/ You can also try the Guiding Assistant which will make suggestions after letting the mount track after a test period of 2 minutes
11/ Only use the Backlash Compensation setting If Guiding Assistant advises to do so.
Go to Brain then Algorithms
Use only if your backlash value from the Guiding Assistant is 3 seconds or less or if the Guiding Assistance says to use this function
Cheers
Good Luck

Martin

[xelasnave]

Thank you Martin.
I had some fun reducing the chip size to 600 x 800 and photograph a tiny gallaxy that appeared in my first test shot and it was amazing how good the result.
The graph suggests to me polar is out but as I have mentioned before it is my belief that the 115 mm is just a little too much for the mount. I balanced everything during the day but needed to move the counter weight over the night and when I did my test shot did not re address balance...Anyways for tonight I will go with the longest exposure it can manage and slowly dial PHD in by following your very helpful advice.
I did away with the long sub and have the sub hub only about half a meter from the lappy and made cabling fall into that set up.
Alex

[Startrek]

Alex
Do you slightly off set your balance “East Heavy” as it does help your tracking and guiding to some degree
All my mounts I adjust the balance slightly east heavy
Some folk do and some folk don’t bother, but I found it helpful particularly with nights of less than favourable seeing
Martin

[xelasnave]

Yes I do yet things change and remember because I am only tracking I am very aware of my mount...when I start guiding it will be interesting to see if I have to pay so much attention to the counter weights. All good.
And I have not yet pulled this mount down and fine tuned it ...so all things considered it ain't too bad.
I am so looking forward to tonight, like last night, some auto guiding and lower gain if I can break the habit..although last night I reduced my gain on what I have been doing in the past but so far having had one unsuccessful processing run I have had opportunity to look for improvement but can't notice it yet.
And given things are starting to work will probably do some darks..even a dither.
I ordered a dew strip but had purchased a small wind screen heater/fan from a car place..Auto Barn? And set it up on the floor blowing up and over the scope which seemed to work ok but hopefully the dew strip will be here tomorrow...Usually I get by with shields but the dew has been terrible recently.
I want to get the two units (old eq 6 and the little heq5) working before I take delivery of the eq8 and whatever scope I get..after last night's experience with the little gallaxy I am thinking 16 inch again:)
And a big score..my daughter decided to replace the wonderful desk she built, mother gets it but I get mothers old (as new) desks)for the roll off..one less thing to source.
And I plan to run the eq8 on its tripod to get a feel for things before I build the pier so that gives me so much more time for other things seeing I don't have to move 2 ton of rock right away.
Just doing a short Lagoon now, from last night, maybe, hopefully my last unguided high gain photo..but really I am amazed what I can get away with using high gain...good to know if you are in a rush.
Alex

[The_bluester]

Rather than specifically east heavy I tend to go slightly counterweight heavy, by enough to ensure that while it will swap sides on the worm and ring gear on the meridian flip it does apply enough pressure to keep them in mesh when the mount flips to be east of pier, pointing west. And I balance the Dec just a sniff rear heavy to try my best to keep that meshed too.

[Startrek]

Alex
Seeing what Galaxies my humble 6” and 8” GSO newts can resolve with an old DSLR , I suspect a 16” Scope with a cooled mono CMOS would capture mind boggling images of similar galaxies
Good luck with your final decision of scope
Martin

[xelasnave]

I doubt if I will be doing meridian flips..as I have to stop staying up past 1 am, so data will be gathered from the East..I also hope to get the mounts to behave very well being confined to say 50 degrees movement or whatever I finally go for...plus at least with the 115 mm it is a tag too big for the little observatory so you need to watch it hitting the wall.
alex

[Startrek]

Alex
Another handy visual aid in PHD2 is the Guide Star Profile Tool
I started using it only a month ago after guiding for nearly 3 years and it’s a very useful tool
Some info below -

PHD2 Guide Star Profile Tool
This tool is accessed in the main screen via the “View” drop down menu

Star Profile Tool displays both
FWHD ( Full Width Half Diameter)
HFD ( Half Flux Diameter)
measurements

HFD is a more stable measure of a stars size and shape and more reliable than FWHM

A HFD measurement of between 2.0 and 4.0 generally means excellent to good seeing conditions
A HFD measurement of between 4.0 and 5.0 generally means good to average seeing conditions
A HFD measurement above 5.0 generally means poor to bad seeing conditions

When selecting a guide star either using “Auto Select Star” from Tools or manual selection, make sure your Star Profile graph shows a sharp peak or tapered peak not a flat or sloped peak
When selecting your guide star ensure the “Signal to Noise Ratio” SNR is generally between 20 and 40 depending on seeing conditions
Don’t select a bright guide star as it will be saturated and will show a very high SNR ( say +50 SNR )You cannot guide on a saturated star
Don’t select a guide star to dim ( say below SNR of 20 ) as you may lose the guide star during guiding

Cheers
Martin

[xelasnave]

Thanks Martin. Although I did not get to guide on my selected object afterwards, like the night before, got it working and did various tests up to 10 minutes..the really great thing unlike my first and early experiences was it just kept working, no lost star, and no it was not a hot pixy, and although the graph was seemingly a bit saw toothed the corrections were not too many and , which is what one should be more concerned about than the graph, was my stars..not perfect at ten minutes but only noticeable when you blew the image up and certainly better than the many stars I have had to round up with various tricks..which I did not do with that recent Lagoon..no deacon even.
But I am not sure tonight will see action so I am adding the additional Lagoon data, at low gain, stacking everything again and of course reprocess..I have done two in StarTools and first time ever got some joy with deconvolution and these are really looking very promising ..just hope I dont stuff them up going overboard.
Thanks again for all your help...
Have you ever thought of doing a you tube video? I have been thinking of doing one for my star trail method for getting a reasonable PA for folk starting..my polar in that Lagoon shot was started via the star trail method because I simply could not find Sig oct for what ever reason..but I dialed in via star trails and tried to see how close I could get before using Pole master.. well star trails got it within a quarter of an inch on screen at normal screen size but I neglected to quantify it in terms of degrees..but my point is I think a video would have folk starting understanding the method which I think when I post it here as I have many times I get no questions and I doubt if anyone is taking advantage of the method when just starting out.
If nothing else beats drift align by miles.
Thanks again for your wonderful help..in fact I think I could say without the help from everyone yourself in particular I doubt if I would have stuck at it.
Alex

[The_bluester]

Are you using EQMOD to drive the mount Alex? If you are and you don't plan on doing meridian flips any time soon, go into the settings if you have not done it already and turn on the mount limits so if you happen not to go to it at the right time, the mount will stop at the meridian (Or some time after if you decide it is safe to do that and set EQMOD accordingly) and help avoid any messy stuff like equipment crashes.

[xelasnave]

Thanks for the tip.
Yes EQMOD for me...when I set up the new scope and mount, whatever the scope I will have room in the roll off observatory so I will try and get things better organised. Wifi and video cameras would be nice and a remote for the roof. I think I will put he 80 mm on the HEQ 5 and use 5he old EQ 6 to mount two DSLR cameras for wide field as the eq6 can go unguided forever just for wide fields. This has gone way past holding a camera at the ep for Moon shots.
Alex

[Startrek]

Alex
If you intend to use EQMOD, I can send a procedure to use Stellarium for your Planetarium for navigation (tracking and Goto) it works unbelievably well , I can find dim galaxies in minutes which gives you more capture time
As I assume you have the older HEQ5 and EQ6 mounts they will require the EQ direct method using the shoestring cable ( not the new USB connection )
Let me know when your ready and I can send if your interested !!
Cheers
Martin

[xelasnave]

Only if it's no trouble Martin. I did try to do it ages ago but at that time as I recall I was unable to devote the attention up here and things never got to work so in effect I will be starting from scratch. I still have Stelarium on the Lappy. I have always had some pride that I was as good as goto but I admit sometimes, when someone has moved an object, they can be annoyingly hard to find so I guess I should get that aspect sorted..thanks.
Alex

[The_bluester]

What software are you using for capture Alex? Stellarium with Stellarium scope will shown you where your mount says it is pointed, but that is only as good as your alignment. You can manually sync things yourself so the mount and the sky agree on where you are pointed, but plate solving with the likes of APT, SGP and others will allow you to sync the mount pointing very easily.

[Startrek]

Alex,
Here’s the EQMOD and Stellarium procedure

EQMOD , Stellarium Scope and Stellarium

EQMOD and Stellarium Set Up EQMOD and Stellarium
(Using Stellarium Scope as the interface platform)
Telescope Control for Synta mounts eg: Skywatcher HEQ5, EQ6 and EQ6-R mounts
*
Please find below and attached documentation to get you up and running with EQMOD telescope control
Note 1: If your using a DSLR, I strongly recommend you buy and download Backyard EOS ( Classic Edition ) from O’Telescope Canada as it will allow easy use of EQMOD and more importantly more accuracy with Polar Alignment, Star Alignment and Goto ( you can control everything from your laptop position – the only time I get up of my butt is to check location of the first alignment star in my finder scope to bring it into view on BYEOS and adjust the AZ and Alt bolts on my mount for PA ) You can also use Cartes Du Ceil planetarium software or any other that supports EQMOD but I prefer Stellarium as its extremely good and easy to use and navigate
Note 2: The information I provide is based on “my set up” using my HP Omen Laptop PC running Windows 10 Home version ( Not to sure about the set up if your using a MAC ?? )
*
Software Required
Ascom ( ascom-standards.org )** Ascom Platform 6.4SP1* latest *( Free )
EQMOD (eq-mod.sourceforge.net )* Eqmod version dated 14/5/18 *or latest ( Free )
Stellarium Scope ( welshdragoncomputing.ca ) latest release dated 26/12/16* ( Free )
Stellarium* (stellarium.org )* version 0.18.2* or latest version ( Free )
Note : Above software versions may have been upgraded since I wrote this procedure always use the latest
Shoestring Astronomy Virtual Com Port ( VCP driver for FTDI chip )* for your Bintel ( Shoestring Astronomy) USB2EQ5 cable ( www.shoestringastronomy.com ) This is the most important item and allows your Laptop to find and connect to the mount .Hopefully your operating system is on the list for the VCP driver ( Go to The Shoestring Astronomy Store then downloads then Virtual Com port drivers for USB2EQ5 ( VCP Driver for FTDI devices ) your USB2EQ5 cable has a FTDI device in the USB end

EQMOD Set Up and Goto Procedure
Once Software is down loaded and drivers are established here is the basic procedure* -
1/ Ensure you set up and run Stellarium a couple of times ( this creates the initialization files to allow the systems to work )
2/ Park Scope, switch off mount and disconnect Synscan hand controller ( if you still use Synscan HC *to Star align and Polar align )
3/ Connect the USB2EQ5 cable RJ45 plug end into hand controller port on Mount then plug the other end which is USB into a 2 meter long USB2 extension cable , then connect this to your USB port on your laptop
4/ Switch on your mount ( Very important – I sometimes forget and wonder why my Com port wont connect )
5/ Check USB serial cable virtual com port (VCP) appears in “Device Manager” of your Laptop under Ports ( Com and LPT )
6/ Open Stellarium Scope and click on “Select Mount” button. This launches the Ascom Telescope Chooser Box window ( move the Stellarium Scope window over to the right hand side )
7/ Select EQMOD Ascom EQ5/6 then click “Properties” and then “OK” the *Ascom Set Up window now appears
8/ In the Ascom Set Up window enter your location data in the “Site Location” section ( this must exactly correspond to the data entered in the Stellarium *location window )
9/ In the Ascom Set Up window ensure “Mount Type” is Synta EQ
10/ In the Ascom Set Up Window ensure EQMOD Port details are – Time out 1000 , Retry 2 , Baud 9600
11/ In the Ascom Set Up Window leave all other settings as default
12/ In the Ascom Set Up Window click on the Port Button ( Binocular icon ) if port and driver are located , the word “Found” appears and the Com port number ( same as com port number in Device Manager in Laptop ) appears in the red box
13/ In the Ascom Set Up Window click “OK” at bottom
14/ In the Stellarium Scope window click the “connect” *box button and the EQMOD HEQ5/6 window will be launched. Minimize Stellarium Scope but do not close it otherwise you will close EQMOD
15/ In the EQMOD HEQ5/6 window click on the “Spanner” icon to expand the whole EQMOD window and then check the “Site Information” section again to ensure it corresponds with the Ascom Set Up window and Stellarium location window
16/ In the EQMOD HEQ5/6 window Alignment/Sync section ensure User Interface is set to *“Append on Sync” , Alignment Behaviour is set to “ 3 Point + Nearest Point” , Point Filter set to “All” and 3 point Selection is set to “Best Centre” All other settings are default
17/ Click on the “spanner” icon again which minimises and just leaves the smaller EQMOD control pad window ready to use the slew control buttons, tracking and parking the mount
18/ Maximise Stellarium Scope which should read at the bottom “ Scope Connected ” then minimise it again for convenience but don’t close it.
19/ Open Stellarium and your ready to use the Goto functions via your laptop keyboard which is CTRL and 1 for slewing , CTRL and 3 for Sync and CTRL and 5 for cancel
20/ The EQMOD target icon will appear on the South Celestial Pole ( SCP) location on Stellarium when your Mount is set ready in the home position
21/ When your ready to slew to an alignment Star or intended target , press “Unpark” on the EQMOD control pad , select your object by clicking mouse on it and then press CTRL and 1 together on the keyboard. EQMOD target symbol will move off SCP in Stellarium and move across to selected target.
22/ To start aligning or synchronising the night sky so EQMOD can use its alignment model , when you arrived at your 1st Star and your Star is centered in your FOV press CTRL and 3 ( Sync function) on the keyboard. EQMOD target icon will move a bit away and then back on the Star again. Your first star is aligned and the more stars you align and sync the more accurate EQMOD becomes with each slew and Goto across the night sky.
23/ The EQMOD control panel has many features including slew rates 1 to 4 speed , tracking for Sidereal, Lunar and Solar and NSEW controls for movement ( Sidereal is the default setting when you first open EQMOD)
24/ When your finished observing or imaging for the night , just press “Park” on the EQMOD control pad and mount will return to your Home Position ( EQMOD target symbol on Stellarium will move back to the SCP location )
Note : For better Goto accuracy use EQMOD, Stellarium and BYEOS *
In Stellarium use at least 2 to 4 sync points ( Stars ) surrounding and in the vicinity of your intended imaging target ( you don’t have to be really close , I’ve used stars 30 to 40 deg away and its works fine but as close as you can )
Click on the 1st sync point star, press CTRL and 1 on keyboard ,mount will slew to that star but not exactly centred, centre your star using EQMOD slew control buttons and view in BYEOS then hit CTRL and 3 on keyboard. Star will be re centred automatically and a sync point count will appear in the EQMOD window. Note: you may have to minimise the EQMOD control pad window first and then press CTRL and 3 to allow the sync function to work properly.
Repeat process for another 2 or 3 sync point stars surrounding the vicinity of your intended imaging target, then click on your intended target , the Goto accuracy should be very good if not bang on target
The above seems like a long winded procedure but after a while you get quicker and quicker ( much quicker and more accurate than your hand controller could ever achieve) The more sync points you use the more accuracy you achieve but I have found 3 or 4 to be enough ( The hand controller can only use 2 or 3 alignment stars for limited accuracy , where as EQMOD can use 3, 6, 10 , 20 or more syn point stars with more sophisticated algorithms in a triangulation or trapezium format for extremely good accuracy.
I have EQMOD control pad window open, Stellarium window open and BYEOS window open ( Stellarium Scope is always open and minimised ) and I minimise between Stellarium scope and BYEOS to perform the Goto* as my Laptop has only a 15.6” screen
I would recommend you set up and play around with Stellarium for a while and get use to it before jumping straight into EQMOD ( I used it to navigate the night sky for a year or so *before jumping into EQMOD )
Stellarium Time Settings (version 0.18.2 )
Found in Chapter 4 ( The User Interface ) of the Stellarium User Manual
Setting Your Location in “Location Window”
Eastern Standard Time
Time Zone should be UTC+10
Tick Custom Time Zone
Untick enable daylight saving time
*
Daylight Saving Time
Time Zone should be UTC+11
Tick Custom Time Zone
Tick enable Daylight saving time
Main Screen “ Configuration” Spanner icon
Click on “Time”
In Start up date and time click on bullseye System date and time
*
Stellarium Location Setting
Refer Chapter 4.2
You can set multiple locations as your default ( I have 2 set up , so I just click on either location in the huge alphabetical world list and the location info is all set up for me
For more information read the EQMOD Project website, Stellarium Scope website and Stellarium website
Hope this gives you a good head start on this great software and telescope control
Good luck
Regards
Martin
*
*
*

[xelasnave]

Wow Martin that looks great thank you so much..There is really so much when you think about it ..I have print out of some basics, and it is just over 1000 pages and I remember when I started I printed out over 2000 pages. I keep meaning to do a check sheet ..not so bad if you are doing it on a regular basis but miss three months which is so easy just with weather or fires and you forget a small detail..like the other night I forgot to put a dew cover on my guide scope..usually put one on the finder scope as routine and of course one pays for those little mistakes with precious capture time. I mean if you were flying a plane check lists are standard procedure.
Thanks again.
Alex

[Startrek]

Alex
Glad to help, hope you can get it up and running soon
It’s not as fancy as plate solving but it works and works well , plus a bit of fun to use as well
Martin

[Pepper]

Thanks for them tips in this thread Martin.
I applied some last night from your troubleshooting bit and it massively improved my guiding. Got rid of the recurring sawtoothing and random drops off the scale.
Thanks heaps.

[Startrek]

Steve
Glad the tips helped your guiding
When conditions and seeing are average to ok ,the little tweaks and tips seem to work well ,but when seeing and conditions are really really poor or you have high cloud around etc... you just can’t adjust you way out of bad guiding no matter what you do
Theres definitely a limit to what PHD2 can do but some folk can’t understand that. It’s only as good as conditions allow it to perform
It generally performs very well