PHD Guiding and guide scope

[blackbetty50 (Mike)]

I recently purchased a Toucam 900nc and adapted an 8x50 finder scope I had left over from a GSO dob that I purchased. I removed the rear eyepiece and rear plate from the finder and located the focal point of the finder and placed the cam into the finder scope.
I am able to focus on objects in daylight with it.
Sat up till 1 am fiddling with the set up trying to get it to work then
last night I took everything out side and fired up PHD guiding, the software locks onto the scope control which I run from an ST4 adapter and a shoestring LPT adapter.
The camera is usb direct to Win xp and the software finds the camera no problems.
I have search extensively for answers to my problem but no luck so far.
When PHD guiding shows a rendition of the stars on the screen, i centered the finder on Jupiter and the 8x50 magnifies it and shows it as quite large and bright, PHD wont lock onto it for some reason.
Should I be locking it onto less brighter, smaller objects?
When I do get it to finally lock onto something it runs for about 5 min then the bottom settings line starts to flash on and off.
I haven't been able to find a definitive list of settings for the 900nc in PHD guiding do I use Iyuy or yuy2? 640 x 320 or 320 x240.
What camera settings should I use? auto, flicker free, black and white etc?
The screen on PHD is a grey colour and not black with the stars in relief is this correct?

[peter_4059 (Peter)]

You need to use an unsaturated star to guide on - I don't believe you will have any luck guiding on Jupiter. Under the PHD tools menu there is an item "Enable Star Profile" - this shows the brightness profile through the star you have selected - you need a peak in the profile - a flat top means the star you have chosen is saturated. The bottom line flashing on/off is normally because it has lost the guide star. There is also a star mass tolerance setting under the brain menu - try increasing this to 1.0. Can't comment on the camera settings.

[mithrandir (Andrew)]

Originally Posted by blackbetty50

The screen on PHD is a grey colour and not black with the stars in relief is this correct?

That sounds like you are using too long an exposure, and possibly not doing any dark frames. As Peter says, the guide star must not be saturated, and has to be a star (planets are not a point source).
Keep reducing the exposure until the grey is as dim as you can get it. The stars should still be enough for PHD to use them.

[blackbetty50 (Mike)]

Thanks guys will give it a go

[ZeroID (Brent)]

I have a similar setup, SPC 880 flashed to 900 and an 8 x 50 scope. I use 640 x 320 but don't touch much of the other settings. I am having simlar issue with grey screen and losing the star but I think a lot of it is the high level of LP I am working with. Mostly on 2.5 second exposure times. Must have another play with it notw I have the big scope back on the mount.
Thanks for the additional info and ideas. If I get anything useful I'll post it back here.
C'mon clouds, give us a break !!

[blackbetty50 (Mike)]

Well I set it up again last night and used some of the suggestions given guys, thanks. Finally got it working.
I set it on 1 sec frame refresh? and moved the gamma solved a few problems. Set the camera options to automatic and black and white and focused on a star.
Used 640 x 320 YUY2 and off it went.
Next question is how do I get stellarium to accept the LPT port for scope guiding?
It only gives me the option of com1 2 etc and if i type in LPT1 it wont accept it.cheers

[peter_4059 (Peter)]

Now you have it going here's some more suggestions:
Go for 2 or 3 secs rather than 1 so you smooth out seeing.
Did it work at 640x480 instead of 640x320? I thought 640x480 was the native resolution of most webcams.
Why do you need to connect it to stellarium? What setup are you using - ie how do you connect the computer to the mount and what mount do you have?

[blackbetty50 (Mike)]

Hey peter, you are probably right at 640x480 as I was going from my dodgy recollection. Not good with numbers at the best of times.
I wanted to connect it to stellarium to make it a bit easier in locating things to look at.
Although i have had the scope for a while I always find it hard to find things of interest to look at apart from the most basic, moon, jupiter and saturn etc
Never know where to point the scope and I thought if I could pick a nebula etc stellarium would direct my scope to at least somewhere near it in the ballpark.
I have a GSO 8 inch newtonian scope which used to be a dob. I only recently purchased a second hand eq5 mount which came with RA and dec motors and I did an st4 conversion on the control box and purchased a gpint-pt guide port adapter to use with it.
Cant find or input the LPT port into stellarium and just wanted a piece of software like a planetarium that I could click on an object and it would guide the scope to the vicinity.
Have looked at Cartes du ciel but it seems harder to work out than stellarium.
Dont know what brand the EQ5 mount is but it looks generic.

[peter_4059 (Peter)]

OK Mike - now I understand. It sounds like you have a non-goto mount and while you can do a guiding mod to provide an ST4 connection to allow autoguiding this will not turn it into a goto mount.

Guiding is all about adjusting the rotation of the mount for accurate photography - not about positioning the scope to locate objects.

I don't believe you will be able to use Stellarium to drive the mount to an object with this arrangement - you need a goto mount for that.

[blackbetty50 (Mike)]

Thanks Peter, did find something which might do what I want to some degree, found an android program called skeye pro. Apparently i can attach the phone to the scope and use it in a manual push to set up. Will give that a try. cheers

[Nortilus (Josh)]

my advice is get a better camera. I have a SPC900 modded for guiding. It sucks. I struggled for ages to get it to work and in the end got a qhy5 qguider. Beats the hell out of the SPC900...

[2stroke (Jay)]

I would mono and lx mod your 900nc if your tight for cash. I would be also hunting down a used dsi pro or getting a qhy5 ect, as there tends to be alot of work and frustration getting guiding working well with a 900nc, not to say it can't be done or anything though. Thanks peter for the saturation info in phd didn't know it had it I herd you can also make the focus off to help with the sat issue even though its great to do to find the centroid anyhow. Having a hell of a time here with flexture issues with the dsi's weight and just built a st80 up with a very tough focusing system and are waiting on these dam clouds in melbs to clear to see if i've got the system finally working sweet.

[Jon (Jonathan)]

Just a word about the grey screen. Using the slider at the bottom of the main screen adjusts the display - so you can darken the sky (and stars) using this, but AFAIK it does not alter the way the software processes the incoming data, just the way it displays it.

If you want to adjust the sensitivity of the system itself, you need to use the "Gain" setting in the Brain menu. It's 95% by default - I sometimes crank it up to 100% if I'm guiding near the horizon, or down to 80% if I want to use a very bright star and don't want it to saturate.

[astronobob (Bob)]

[QUOTE=blackbetty50;1010954]i centered the finder on Jupiter and the 8x50 magnifies it and shows it as quite large and bright, QUOTE]

Also on this note of (not to guide on Planets) is that planets do Not traverse the sky at the same speed as which stars do, hence trails over a period of time