PHD and SPC900NC webcam

[nightvision]

I have been trying to get PHD to work with my 900nc webcam, its attached to a 62mm fast scope.

Everything works well with WxAstroCapture but PHD produces very low quality images (lots of noise and moire patterns and the occasional clear image) and intermittently drops frames. Read the help files and even with all the adjustments available it still struggles to deliver a clear image. Just changing the exposure time seems to throw it all into instability, seems like PHD is struggling to work with the camera drivers.

WXAC is rock steady with very clear and stable images. I can see PHD has more features so it would be great to get it working.

Anyone tried this sort of set up?

[themos]

Is this a modified webcam?

[nightvision]

Yes modified with LE on RTS/Serial and shutter switch but no amp-off mod or RAW mod. PHD is able to use the RTS connection.

[astromerlin]

Hi, I've had a similar experience with PHD. Things I've learned are that PHD looks grainy and has spurious patterns until it detects a star then you get a clearer image (black and white). With the spc 900 as standard with gain up at 80-100% there are quite a few bright stars to practice getting the guide settings right. I have yet to achieve this.

With a modded SPC I have found instability in getting consistant clear images with the exposure set less that 4-5secs still with a dropped frame now and then which throws off the guiding.

Seeing that my computer is 5 meters from the scope, the webcam and LX goes to a hub and through an active usb lead I was thinking this could be the problem with the dropped frames due to some delay perhaps. I am now thinking of running a laptop at the mount and remote viewing from this.

Athough this doesn't help you I thought I'd share my experiences although it would be interesting to hear other peoples views about the LX dropped frame issues as it does make for disappointing guiding.

[Glider]

I use an SPC900NC on a finderguider and/or ST80 and have never needed to enable the LX mode to get a guide star.

Do you mean 62mm fast guide scope ^^^ or is it a typo?

[nightvision]

Hi Astromerlin, that's exactly what I am getting, the help files mention some setting incompatibilities but I have tried all combos. I suggest you download WxAstroCapture and see just how good things can be.

Conclusion so far is that PHD doesn't really handle the modified 900 very well.

Hi Glider, sorry that's the objective size, it's a scope I made up from my bits box, it's about F2.5, uses an old 62mm spotter objective along with a 50mm bino objective as a focal reducer. Very bright and clear (plenty of stars even at 0.6 second exposures), should be good enough to guide my old Meade mount and the 300d with just some shortish lens attached (50mm and 135mm).

I am finding out (cheaply) if I really want to spend more and get a good mount for the 100ED and start on the slippery slope to imaging induced bankruptcy!

Tony.

[Glider]

As I say, I've never turned the LX mod on, all I can say is that PHD is great with an unmodified webcam.

[astromerlin]

Strangely enough I use WXastrocapture for imaging and have never used the guiding part of it. How did you get on with it? Is the guiding consistant (lx mode on).

[nightvision]

I am just testing using simulated stars and it seems that PHD is lot better at tracking movement, Wx easily gets lost.

I decided to have another go at making PHD work. The settings that worked when in LE mode are below. I found that setting the capture to 1, 2 or 3 seconds stopped the dropped or trashed frames. Half seconds messed things up. I also found that turning the gain down and increasing exposure times reduced the noise and improved image quality. I can see that Wx has better image quality (for its primary capture task) but I think PHD sacrifices this for better tracking by deliberately pixelating the image.

Using the PHD unmodified Web cam option (and no LE mode) didn't seem to produce a bright enough image (it was stable) so I can see how this would work with a bigger guide scope.

If Wx could be made to work I think it could do guide and capture at the same time, I will be using my 300d for capture once I get a decent mount.

[astromerlin]

Yes, I think it is probably the case that I need to spend a few nights getting the settings right with PHD. I have no problem with finding stars but it seems to keep moving the mount eastwards and I havn't sussed why yet. Polar alignment is spot on so it's probably just the settings or my mount. Too eager to get imaging with the few clear nights though.

Get yourself a good strong mount for that ED100, you wont regret it.

[nightvision]

As I say, I've never turned the LX mod on, all I can say is that PHD is great with an unmodified webcam.

I guess the ST80 is a bright scope, it's on my shopping list for sure. Do you have the IR filter installed on the 900?

[nightvision]

Yes, I think it is probably the case that I need to spend a few nights getting the settings right with PHD. I have no problem with finding stars but it seems to keep moving the mount eastwards and I havn't sussed why yet. Polar alignment is spot on so it's probably just the settings or my mount. Too eager to get imaging with the few clear nights though.

Get yourself a good strong mount for that ED100, you wont regret it.

Would that be an NEQ6?.... one day soon I hope.

[themos]

I use an LX-modded webcam on a 300mm-focal-length f/4.5 lens. I had trouble with PHD for a while but it's a lot better now (maybe one bad exposure in one night). First of all, get the latest version of PHD. Then, keep the frame rate to 5fps and the exposure at 1 second (or maybe 2 seconds, I usually find a guide star by repointing the lens in its rings). Auto Exposure OFF, Auto White Balance OFF, Black & White ON, as you have. The parameter to play with to avoid dropped frames in PHD's "brain" is the "LE read delay", I think mine is set to 12.

[themos]

http://www.stark-labs.com/depot/beta/Setup_PHDGuiding_1_12_3.exe

is the latest