PHD2 Help particularly post meridian flip

[IDM]

Hi,

I am having real problems with my guiding and would grateful for any thoughts or advice.

I am using an Ioptron IEQ30 pro mount, the guide scope is an Svbony 50mm 190mm focal length guide scope with a Zwo 120MC guide camera. I carried out calibration at the start of the run followed by using the guide assistant and accepting all the changes it suggested. The guiding started off reasonably ok (not brilliant), I left the rig to run overnight with the main scope taking 60 second subs, so eventually it started to get light which obviously destroyed PHD2’s ability to guide! However, at some point in the night the mount did a meridian flip and looking at the 60 second subs the mount starts moving in both RA and DEC, with only the occasional decent sub. I have attached the guide log (entry 10 is obviously the overnight run) in case someone can help diagnose something I am not doing right.

I see there is an option to do calibration post meridian flip but don’t really understand how to do this, again any help gratefully received.

Thanks,

Ian

PHD2_GuideLog_2023-10-21_190636.txt

[Budgie1]

What other software are you using, apart from PHD2?

I use APT and after the meridian flip is doesn't automatically restart PHD2 guiding unless the "Control Guiding" box is ticked in the APT Guiding Settings. 

[carastro]

I only use PHD1.  I have to tell it to recalibrate after a flip.  There could be an auto-setting for this that needs ticking.   Hopefully someone used to PHD2 will reply soon  

 

Edited October 22, 2023 by carastro

[AndrewRrrrrr]

looks like it clouded over at 03:04 and never cleared up.  what time was your flip?

 

[WolfieGlos]

If you’re using NINA to control your imaging session, use the sequencer for your imaging, and set Start Guiding to on. When starting the session, and after a meridian flip, it will automatically establish guiding, settle, and then start (or restart) the imaging run. 

[IDM]

11 hours ago, Budgie1 said:

What other software are you using, apart from PHD2?

I use APT and after the meridian flip is doesn't automatically restart PHD2 guiding unless the "Control Guiding" box is ticked in the APT Guiding Settings. 

I am using PHD2 with Sharpcap.

I suddenly feel like I have hit the wall in terms of my understanding and I probably need  to read deeper into the software manuals! 

[IDM]

10 hours ago, WolfieGlos said:

If you’re using NINA to control your imaging session, use the sequencer for your imaging, and set Start Guiding to on. When starting the session, and after a meridian flip, it will automatically establish guiding, settle, and then start (or restart) the imaging run. 

I need to get an understanding of the sequencer in Sharpcap. As a relatively new imager I haven't tried to do overnight runs until this year. I must find a good guide to the Sharpcap sequence planner.

[SteveNickolls]

Not sure which version of SharpCap you are using but they all have a written manual. The latest version is for version 4.1 of SharpCap. Good look reading up on the subject.

I note you are using an iOptron mount do you involve iCommander to control your mount?  The software has settings on what you wish the mount to do at or near the Meridian.

Cheers,

Steve

[Tomatobro]

On the Sharpcap forum I asked if when doing a meridian flip PHD could be turned off to stop the loss of star alarm. Sharpcap have just released a manual update but I had a quick look through and MFlips are not mentioned.

When a flip is required I stop PHD, park the mount, Re acquire the target, plate solve then restart PHD. I have used Sharpcap's sequencer but have not done this process in the sequencer. I also have the dome rotation to do to align with the scope. Experience tells me that so much can go wrong during this operation that its best to be awake and watching

[Tomatobro]

this sequence was posted on the Sharpcap forum. May be helpful.......

 

SEQUENCE
GUIDING CONNECT ABORT True
TARGETNAME "AD Leo before"
PRESERVE CAMERA SETTINGS
MOUNT GOTO "10 19 36.27 +19 52 12.1 "
DELAY 20
SET GAIN TO 500
SET EXPOSURE TO 10
MOUNT SOLVEANDSYNC
DELAY 20
END PRESERVE
GUIDING START
DELAY 20
STOP AT -1 FROM MERIDIAN
CAPTURE START
DELAY 200000
END STOP AT
CAPTURE STOP
GUIDING STOP
TARGETNAME "AD Leo after"
PRESERVE CAMERA SETTINGS
MOUNT GOTO "10 19 36.27 +19 52 12.1 "
DELAY 20
SET GAIN TO 500
SET EXPOSURE TO 10
MOUNT SOLVEANDSYNC
DELAY 20
END PRESERVE
GUIDING START
DELAY 20
STOP AT LOCALTIME "5:00 AM"
CAPTURE START
DELAY 200000
END STOP AT
CAPTURE STOP

[IDM]

34 minutes ago, Tomatobro said:

When a flip is required I stop PHD, park the mount, Re acquire the target, plate solve then restart PHD. I have used Sharpcap's sequencer but have not done this process in the sequencer. I also have the dome rotation to do to align with the scope. Experience tells me that so much can go wrong during this operation that its best to be awake and watching

Last night was clear so I thought I would just play with the guiding and eventually got half decent RMS, luckily the mount quickly did a meridian flip and as expected the guiding was chaotic. So I stopped guiding, did a plate solve (without going to park). I then deleted my calibration data in PHD2 and restarted PHD2 and let it recalibrate, followed by guiding assistant. The results were however, awful, I went from 0.8RMS to 2 RMS post flip. Maybe parking would have been a better idea? I  am unsure if I have software or mount problem, or possibly both. I felt very frustrated and to cap it all its the last clear night I will see for a week. Feeling rather despondent this morning.

Also is there an easy way to know approximately what time the mount will do the flip? 

[IDM]

45 minutes ago, IDM said:

Also is there an easy way to know approximately what time the mount will do the flip? 

I answered my own question by reading the Sharpcap insruction:

"A negative Local Hour Angle means that your mount is heading towards the meridian and (for equatorial mounts) may need to flip orientation to continue imaging past the meridian. For instance a Local Hour Angle of -00:25:00 means that your mount will reach the meridian in 25 minutes"

[WolfieGlos]

1 hour ago, IDM said:

I then deleted my calibration data in PHD2 and restarted PHD2 and let it recalibrate, followed by guiding assistant. The results were however, awful, I went from 0.8RMS to 2 RMS post flip. Maybe parking would have been a better idea? I  am unsure if I have software or mount problem, or possibly both.

You don't mention what scope you have, but could it possibly be a balance issue?

I suffered something similar at the start of the year when I first got my HEQ5, and then a few months later upgraded my scope to the Starfield 102ED below. I set everything up, balanced it and found that post meridian flip the RMS was similar to what you reported there.

I realised.....rather embarrassingly, that I had balanced the DEC axis with the dew shield retracted and the cap on! By moving the dew shield out (it's about 10 inches...) and removing the cap, DEC balance was way out. After correcting this...I've never had a problem since.

[Tomatobro]

Three clear nights in a row will test my stamina so is all it will take for me to look again at Sharpcaps sequencer😑

[IDM]

3 hours ago, WolfieGlos said:

You don't mention what scope you have, but could it possibly be a balance issue?

The scope is and Altair 70EDQ-R F5:

Altair 70 EDQ-R F5 Quad APO Astrograph (altairastro.com)

Which with camera, and guidescope weighs in at about 5.5kg (from memory). I don't think its a balance issue as the Ioptron mount has very little resistance to movement so even slight imbalance makes it move when the clutches are released. I generally do a final balance when the scope is on-board with all cabling etc and haven't as yet forgotten the dew shield or to remove the lens cap.

[alacant]

On 22/10/2023 at 13:22, IDM said:

any thoughts or advice

Hi
Are you sure you have the time and location set correctly? I think SC may take some values from the operating system;  the calibration took place more than 8 hours from the meridian at DEC 50º.
Cheers

Edited October 23, 2023 by alacant