Phd guiding problem

[barrie greenwood]

Hi guys I'm sure this has been asked before I've searched bit cant really find anything .

I'm trying to guide using phd and also phd2 but not having much luck .

I've set up my guidescope and I'm using a Samsung scb 2000 camera as a guide camera.

Once connected it shows up stars etc and allows me to pick a star and it goes into calibration and it sometimes calibrates Ok and starts to guide but then looses  the star snd gives an error something about the mount and guiding maybe ineffective. 

All connections are good and cables are sound is this something in the settings or is my set up not capable of guiding .

As always any information will be gratefully received. 

Thanks in advance best regards Barrie 

[michael8554]

Hi Barrie

Post your PHD2 GuideLog - look in the PHD2 Folder

Michael

[barrie greenwood]

Ok ill take a look for it 

[barrie greenwood]

Ok here is the guide logPHD2_GuideLog_2021-11-21_103045.txt

[Tomatobro]

was the mount pointing at the Pole star when you tried to calibrate?

[Pompey Monkey]

You need to be pointing somewhere near the celestial equator for the calibration to work (after polar alignment, of course).

Pointing at the celestial pole to calibrate, like you were, will give wildly inaccurate results. Because maths.

Good luck!

[newbie alert]

The whole point of pointing it to the equator/ meridian to calibrate more or less the worst area to guide.

Are you pulse guiding or using st4?

[barrie greenwood]

I'm using pulse and it was pointing at Vega

[newbie alert]

5 hours ago, barrie greenwood said:

I'm using pulse and it was pointing at Vega

Ok, next clear skies(????) Point it south, Click on the drift tool, that brings up where you're pointing.. slew the scope so you have 0 Dec and as close to 0 in az as you can, but pay attention to what side the scope is on.. if it's on the east side of pier then have a -  .....  then calibrate..

Edited November 22, 2021 by newbie alert
Added info

[barrie greenwood]

3 hours ago, newbie alert said:

Ok, next clear skies(????) Point it south, Click on the drift tool, that brings up where you're pointing.. slew the scope so you have 0 Dec and as close to 0 in az as you can, but pay attention to what side the scope is on.. if it's on the east side of pier then have a -  .....  then calibrate..

Ok I'm lost here point the scope south yeah? if that's the case then 0 dec would be east .

Do u have a step by step for idiots I don't need any real detail just an abc ish .

Thanks newbie

[wimvb]

If you point the scope south, the counterweight bar on an eq mount will point due east or west. 0 dec means that you are looking at the celestial equator (which is earth’s equator extended). From the horizon, look as many degrees up as 90 - your observing’s location latitude. For me at 60 deg latitude that would be 90-60=30 deg up. When you do the calibration, you shouldn’t point lower than 40 degrees though, so you avoid atmospheric disturbances.

[ollypenrice]

Why not calibrate close to the pole? Just think of the size of the circle described by a star up there during one sidereal day: it's tiny, meaning the star hardly moves in a day, let alone in the time taken to calibrate. That means that the calibration can obtain very little information about the tracking error since it is compressed onto a tiny circle. If you calibrate near the equator that circle opens up into what is approaching a straight line from the mount's point of view so it has much better information about the effects of tracking error.

If you wanted to see if the stars appear to move with naked eye and chose Polaris, you might think they didn't. If you chose Betelgeuse you'd soon see that they did.

Olly

[newbie alert]

7 hours ago, barrie greenwood said:

Ok I'm lost here point the scope south yeah? if that's the case then 0 dec would be east .

Do u have a step by step for idiots I don't need any real detail just an abc ish .

Thanks 

In simple terms, point it south and about  45 degrees... click on the drift tool.. this brings up a box with the coordinates of where it's pointing...  slew the scope and get the DEC on 0, and as said previously,  depending on which side of pier the scope is, depends what side of the meridian you want to be + or minus.. minus if the scope is on the east side, but fairly close to zero... plus if it's on the west..then calibrate

If you calibrated on Vega I'm supprised it didn't flag up saying that it's too far from the equator 

If you theoretically shoved a pencil through both poles . At night you can see the tip of the pencil pointing more less at polaris , you cant see the pencil sticking out of the south pole as its through the earth...and the high side of the 23 degree tilt will be the equator..  hope this doesn't confuse even more, it's not intended

[barrie greenwood]

Ok I'm more than a bit confused here is a shot of the ascom where ithink you guys mean

[newbie alert]

Easier to click the drift tool

[wimvb]

Looks good in ascom. But as I wrote before, if you increase alt a little, you’ll have less disturbance from the atmosphere, and neighbours’ houses.

Edited November 23, 2021 by wimvb

[barrie greenwood]

Drift tool?? 

I set it at that just to see if understood you guys correctly. 

So I calibrate it around that area and once calibration is done I can then pick an object slew to it pick a guide star and guide I'm I correct .

Regards Barrie 

[newbie alert]

1 hour ago, barrie greenwood said:

Drift tool?? 

I set it at that just to see if understood you guys correctly. 

So I calibrate it around that area and once calibration is done I can then pick an object slew to it pick a guide star and guide I'm I correct .

Regards Barrie 

Drift tool in phd.. under tools 

In the advanced settings there's a tick box to check to maintain calibration,  so once done you won't need to callibrate everytime 

[barrie greenwood]

Thanks guys could be some time  before I get to try it the weather looks terrible for the next couple of weeks 

[michael8554]

Hi Barrie

From your GuideLog:

Your exposures are only 20mS, is that as slow as the Samsung scb 2000 will go ? Most guiding is done at 2 to 4 seconds exposure.

As a result there were many "Star Lost" messages, particularly during Calibration.

The mount driver is reporting this guiderate setting:

RA Guide Speed = 13.5 a-s/s, Dec Guide Speed = 13.5 a-s/s,

But the Calibration has calculated the guide rates as only:

 RA = 3.4"/s , Dec = 4.1"/s;

This suggests you have the ASCOM PulseGuide Setting in EQMOD too low.

You say "I've set up my guidescope",  and the focal length is entered as 1000mm, is that correct ? 

Or are you using an Off-Axis -Guider ?

So the guide image scale is only 1.3arcsecs/pixel, a 300mm guidescope would show more stars, and give 4.33arcsec/pixel.

Read this, particularly clearing backlash before Cal:

https://openphdguiding.org/phd2-best-practices/

Michael

Edited November 24, 2021 by michael8554

[barrie greenwood]

Hi guys .

Ok after reading the posts on this there was a lot to look into however in between gusts tonight it's guiding to a reasonable amount the high wind is killing it but ive managed to get it to play along .

There are lots of settings to play about with and I had a real issue with an error reporting its wasn't moving the Dec enough where is the setting that I can change that with. 

Also no I'm an idiot the guide isn't 1000mm that's my main scope the guide is 60mm the camera is z lot better on 1 sec exposure as well .

Regards Baz 

[barrie greenwood]

Ok attached are a couple of sots of the guiding I don't think its great any tips on the settings or how to tighten up the guide .

Regards Baz 

[newbie alert]

Are you drifting as your DEC looks like it's drifting upwards of the trend and your RA is going opposite  ,so balance and PA could need to be tightened up

What mount are you using,  and what's the rest of the setup?

Just before you calibrate on some mounts its advised to take the slack out of the DEC gear... once you have calibrated run the guide assistant and apply the  recommended settings

1 sec loop might be too short.. it's ok in bad seeing to keep the exposures short, but if you're losing the guide star because of conditions then maybe it's not that great to be imaging anyway

[barrie greenwood]

Hi its an eq5 pro mount not the heq5 .yeah could be the polar align or balance slightly off but the mount is at the limit of its weight if not over .

I may need to down size my scope or up the mount 

[scotty38]

Are they the default settings with aggressiveness at 100% on both axes too? Sorry 92% on RA, could have sworn I saw 100...

Edited November 27, 2021 by scotty38