Guiding after forcing a flip in EQMOD

[Ivor]

Last night I was trying to forcing EQMOD to do a meridian 120 minutes early so I could leave the camera going as I had an early meeting in the morning. This failed as it kept flipping back so I gave up and this morning I've discovered the "force flip" selector in EQMOD which will sort it out. This has got me thinking about my guiding as this will be flipped as well, previously I've come out of PHD and completely recalibrated but is there a similar selector or a way to avoid this?

Or is this completely unnecessary?

[The Thing]

PHD2 deals with it automatically, if it didn't then it could easily come a cropper as it can automatically reload the last calibration data so would be in a mess if you had been on the other side of the pier recently.
PHD2 Beta 3

"Many functionalities have been added that increase efficiency, e.g. retention of calibration data, automatic adjustment of data after a flip, ability to retain and recall multiple profiles of equipment. Just a short list."

[Ivor]

Thanks Duncan, you've been suggestion I change to PHD2 for ages I'll give a go.


I'm also interested in how AA5 works I'm thinking of using one App going forward as I want to use dithering. PHD2 offers this but I'm not sure how it does the dither after every sub without knowing the duration.

[The Thing]

Your capture software needs to talk to your guiding softeware and ask it to dither and by how much, and not to resume shooting until dithering is completed. APT does this as do many other programs. Make sure you turn on the PHD server (Tools menu) and check your capture software for compatibility. PHD is very well supported.

[Ivor]

Mixing success last night, guiding with PHD2 worked but not as tight as PHD as the stars are slight elongated

PHD sub




PHD2 sub



I could find the PHD2 log file so I copied the screen



Added to that when I did the flip the mount wouldn't stay put in one place it kept moving; the west side of the mount was fine.

https://vimeo.com/81175646

Any thoughts?

[The Thing]

Hi Ivor,

I get the elongated stars in RA problem as well, I find I just have to have the RA axis properly unbalanced and then it goes away. Being a little off PA also seems to exacerbate this problem. I got elongated stars in both directions with PHD 1.14.3...

On my setup (1250mm OAG) that graph would be excellent. I get deviations of between 1 and 2 arcsecond which is as good as it gets as the seeing is worse that that usually. You should put your guide focal length in the Brain so there is an arcsecond readout on the graph. This allows a comparison of guide errors to the seeing as estimated by various websites.

Try increasing the minimum motion value until the guiding is no longer responding to the seeing, I find 0.30 to 0.40 works on for me, but on a bad night it may have to be 0.50 or so on both axes (with the QHY5). My QHY5 guides at 1.12" per pixel and the new QHY5L-II at 0.62"pp (well oversampled). The 1000D images at 1.04"pp.

Also turn aggression to ~80% and hysteresis to 0 otherwise you will probably be over correcting. I find 100% and 10% make the RA axis jump back and forth across the center line.

As to what happens after a flip, I never have the mount flip while I'm imaging, I start one side and stick with it. After the mount has passed the horizontal I pause the exposures (easy in APT), shift the weights so the scope is the heavy end and then restart. I sometime loose the sub being taken as the scope moves across the horizontal due to moving from one face of the worm to the other, but if I am properly unbalanced (people keep telling me that!) that can be avoided.

Hope that helps.

[Ivor]

Thanks Duncan, I shall go through your list of suggestions and see how I get on. Unfortunately my kit has the camera protruding out the back some way so I can't get past 01:00 without a problem. Having seen Jim's extension tube on his mount I think I'll get one for the EQ6.

I've downloaded AstroTorilla as well so hopefully I can eliminate any errors in PA.

How do others with refractors deal with this?

Do others follow Duncan's approach or take a different one?