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Multitude of PHD Problems (Maybe!!)


SniffTheGlove

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My current setup is an EQ6 controlled via EQMod with a PHD QHY5 Finder Guider and a Canon 350D (35-80mm f5.6 lens instead of an OTA).

The QHY5 Finder Guider and a Canon 350D sit on a homemade bracket made out of 2x1 wood and this is clamped onto the EQ6 head where the dovetail would fit.

I have tried for the last few nights and played around and altered the PHD settings to what has been stated here on SGL ( )

I then tried doing some simple guiding tests last night but for some reason after about 2mins PHD starts to ping and flash RED. I have no idea what it really means but think that PHD has lost the star.

The QHY5 is fitted to a SW 9x50 finderscope and the image shown in PHD is of a slighty defocused image (as suggested here in SGL)

I have calibration ticked with a setting of 3500 in the brain.

I have also got PHD to choose a star and the same still happens.

I open the graph when guiding and it is reasonable flat until the red and blue lines go off the chart and then the red flashes and the pings come.

Any ideas anyone to what might be happening.

Also when I connect the camera to PHD (ASCOM Late) then choose the QHY5 I notice in the proerties box that the gain is set at 50%, however when I then go into the brain the gain is greyed out but shows 95% and the screen images is really grainy.

Any ideas how to reset the gain to the 50% default?

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I use the QHY5 & SW 9 x 50 Finder as well. I did have the red flashing you write about last time I was out. It was caused by 'slightly off-focus stars getting worse to to dew forming on the finder lens making the stars even more 'out of focus'. I wiped the lense with a tissue & focussed until the stars were as small as I could get and had no further problems (that night anyway - not been out this week!).

Might not be the cause of your problem but, something to be aware off.

Pete

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Try using the normal QHY5 driver instead. Minimum motion should be 0.5 for a finderguider.

Also try a little test by using the manual guide function to see it you can move it that way. Here is a typical graph from my finderguider (also on an NEQ6):

index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=72174

post-5513-0-15042600-1347653114_thumb.jp

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I know my PA my be slightly out as in the current location I can not see north but I have made an attempt at drift align.

I tried again tonight and I have attached a screen dump of what happened.

First off the calibrated went ahead and finished once it had gone past the 25 movement and started guiding as you can see from the image excatly how it went.

I shall make the change for 0.5 min distance and see what happens but the clouds have rolled in so will try this tomorrow.

post-8769-0-82939800-1347659153_thumb.jp

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Maybe you can try the beta firmware for the handset, it has a routine so you can finetune your PA. Also your min dec motion looks a little low, increase it to 350 and see what happens. Additionally, if the graph is going down - change the guide mode to south (that pushes it up), and vice versa if you graph is going the other way.

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My setting is ASCOM under Mount menu. Is this what you need for pulse guiding under EQMod? My version of PHD 1.13.1

A question. When doing PHD calibration should EQMod be doing Sidereal Tracking?

A question. When doing guiding should EQMod be doing Sidereal Tracking?

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A question. When doing PHD calibration should EQMod be doing Sidereal Tracking?

A question. When doing guiding should EQMod be doing Sidereal Tracking?

Yes for both. When you slew to a target EQMOD should enter sidereal tracking mode. Then it's a case of choosing a guide star when setting up for guiding and then calibrating. Then once calibrated PHD switched to guiding. PHD is correcting errors in sidereal tracking.

Edit: Removed some mackem so it made sense.

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Yes for both. When you slew to a target EQMOD should enter sidereal tracking mode. Then it's a case of choosing a guide star when setting up for guiding and then calibrating. Then once calibrated PHD switched to guiding. PHD is correcting errors in sidereal tracking.

Edit: Removed some mackem so it made sense.

Thanks for that clarification.

Tom, I am using EQMod and a HitechAstro EQMod Interface using Pulse Guiding. Are you saying I should change all this so that the QHY5 outputs directly to the ST4 port on the EQ6 and use "on-mount" guiding in PHD and disable pulse guiding in EQMod. Would this method have any additional benefit over pulse guiding?

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Thanks for that clarification.

Tom, I am using EQMod and a HitechAstro EQMod Interface using Pulse Guiding. Are you saying I should change all this so that the QHY5 outputs directly to the ST4 port on the EQ6 and use "on-mount" guiding in PHD and disable pulse guiding in EQMod. Would this method have any additional benefit over pulse guiding?

Not sure there's any benefit. I've never tried it the other way round.

Typed by me, using fumms...

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I thought minimum motion was calculated on what your focal length of the imaging scope was and not the guider?

0.5 was the recommended value suggested by Craig Stark for finderguiders, Ive stuck with it and never had a problem since. Minimum motion is the setting for how far the guide star has to move before triggering a guide command. With the short FL of a finder, this value needs to be smaller for it to detect any movement.

Sean ,the setting you need to change to 350ms is the max dec duration (yours is set to 150 at the mo). If it corrects a bit too much, drop it to 300. My default settings are usually between 200-300ms.

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Are you saying I should change all this so that the QHY5 outputs directly to the ST4 port on the EQ6 and use "on-mount" guiding in PHD and disable pulse guiding in EQMod.

For me, the simple answer is yes.

Its all ive ever used and its easy peasy, the only time it wont guide is when there is a cloud in the way :)

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For me, the simple answer is yes.

Its all ive ever used and its easy peasy, the only time it wont guide is when there is a cloud in the way <img src='http://stargazerslounge.com/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt=':)' />

Haven't tried the more complicated method of using EQMOD to guide, but I agree - using the autoguide on the QHY5 works every time and is simple.

Typed by me, using fumms...

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1ms exposure is going to be causing you problems for sure, I rarely go below 2.5ms as seeing and atmosperics will cause your guide star to jump about all over the place.

Also make sure your not guiding on a dead white pixel :)

I think you are talking about exposure times for the QHY5?

What I do is calibrate at 2 seconds, then when I want to guide - I change it to four seconds and that gives me a fair selection of stars to choose from, and as you mentioned helps cancel out any disturbances caused by the atmosphere or passing cloud (if its not too thick).

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Have you tried calibrating at the camera speed your actually going to use? Maybe jumping from 2 to 4ms is what is causing you issues.

George, im not the original poster ;) there must be some misunderstanding.

Nothing wrong with my guiding here, my graph is a flat as a flat thing thats been run over by a steamroller :)

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I exposure was 2.5secs when I started this thread. Not sure where 1ms came from George?

Cloudy last night so did not do anything however I did move things around abit in the Obsy to give my a little bit more space and horizon viewing by moving the EQ6 tripod close to the obsy opening. Previously the EQ6 wa setup with my 10in F7 onboard but as I am no longer using that and just using a Canon 350D and Lens (along with QHY5 Finderguider etc) that meant I could move and park the mount without any clashing. So I still don't have sighting to Polaris to do PA but I will attempt with drift aligning using the canon exposure as per scopetrader.com/?l=/messageboard/view.asp&ID=110&astronomy-article=Zeroing-it-in.--Using-a-DSLR-or-CCD-to-align-your-scope

I know it will be more difficult with a 35-80mm lens but this is all I have at the moment until I can sell my 10in F7 to fund a larger lens or 80ED unless someone else knows how to do decent alignment without a scope attached.

I do have my initial alignment I could do today, ie plant a 2m pole (vertically) into the lawn and then when the sun (if it's out) crosses my local meridian I just pull some string tight so that it follows the shadow line and align the mount onto that taught string line, then look down the lens and finely adjust the mount head/camera to align with the pole. Then follow the Zeroing-It-In instructions from the above URL. This should get me near.

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