SW Finder Scope with MS LifeCam Cinema for Guiding

[Gina]

I've been looking into attaching my MS LifeCam Cinema webcam to my 9x50 finder scope, with a view to using it for guiding. Firstly, I thought the focal plane was inside the tube but it's actually several mm outside. So much so in fact that it seems the webcam cane be fitted in place of the eyepiece. The body of the Cinema is actually just a bit smaller than the eyepiece thread. If I hadn't cut the front end of the casing back to the sensor I could have just padded it out to fit inside the EP thread. Now I'm looking a pieces of pipe etc. Watch this space...

[Flying Eye]

I shall watch what happens next with great interest!

Go for it!

[Gina]

Found a scrap piece of 28mm copper water pipe that I think will do the job. Next to cut a piece off and see how things fit.

[Flying Eye]

Found a scrap piece of 28mm copper water pipe that I think will do the job. Next to cut a piece off and see how things fit.

Wow, that's close, maybe "polish it with sandpaper" close!

[Gina]

I cut off a 2" piece of pipe and fitted the webcam inside it - with the image sensor about half an inch inside the pipe. I then fitted the pipe into the end cap of the finder. Connected to computer and tried focussing out of the window on foliage and trees. Focus was obtained still too far out - pipe not long enough. So now I've cut off a 3" length of pipe, cleaned it up and sprayed the inside with matt black paint. I'll try that later.

[Gina]

Wow, that's close, maybe "polish it with sandpaper" close!

The pipe is just the right size for padding out with a couple of layers of insulation tape to fit the screw thread in the end cap. Likewise the Cinema webcam fits nicely inside the tube with a couple of layers of tape.

[Gina]

Made up the new pipe, webcam and finder-scope and got focus on distant trees. Next thing is to put it on the main scope and point it at the horizon. I expect to do that this afternoon. I'll post pics as well.

[samtheeagle]

Looking forward to seeing what you've knocked up Gina I got very luck with my camera / 50mm finder combo. With the lifecam electronics fitted into a 25mm EP body the sensor was perfectly positioned with the EP body was inserted into the finder... Previously when using a DSI as a guider I had to use a 2X barlow to be able to get focus, as the DSI sensor was set too deep in the camera body :S

I think you'll be pleased with the combo

[Gina]

Thank you

[Gina]

Here are a few photos of the webcam and fitting in the finder-scope.

1. Close-up of the front of the modified webcam showing the image sensor and green (couldn't find the black) insulation tape wrapped round it to fit inside the pipe.
   
2. The webcam side view, and the two pieces of pipe.
   
3. Webcam fitted in 3" long pipe and pipe fitted into scope end cap padded out with tape (found the black ).
   
4. UV filter fitted in end of pipe to keep dust out.
   
5. Complete scope with fitted webcam
   

[Flying Eye]

That is looking good so far. Sounds like it's all working out pretty good functionality wise too.

[Gina]

Thanks A job cropped up and I haven't had time to go out to my obsy yet but still hoping to do it today. Just in for a cuppa

[Flying Eye]

Thanks A job cropped and I haven't had time to go out to my obsy yet but still hoping to do it today. Just in for a cuppa

It's not a race you know. I know, when it flows, it just flows!

[Flappytango]

Good work,

I am anxoius to see how well the Cinema works for picking up stars for guiding...

One caution, i also was trying to determine the focal plan on my 9x50 and a SPC900.. I found that the focal plane is considerably futher outside the tube on close objects than for distant objects.

I hope your trees were far away.

[Gina]

Good work,

I am anxoius to see how well the Cinema works for picking up stars for guiding...

Yes, I'll be glad to get it on the stars. Goodness knows when we'll see them again!

One caution, i also was trying to determine the focal plan on my 9x50 and a SPC900.. I found that the focal plane is considerably futher outside the tube on close objects than for distant objects.

I hope your trees were far away.

Yes, the trees were about 2 miles away. And yes, I did find the same as you with closer objects.

[Gina]

I put the finder-guider on the main scope and checked the webcam worked and that I could get focus 2 miles away with spare inwards movement available (using SharpCap to check the webcam). Still cloudy tonight so no stargazing

On to the next project until the weather lets me do some testing...

Must say that with so little clear weather I'm beginning to wonder if all this preparation for what just might be is one gigantic waste of time and money Am I in the wrong part of the world??!!

[Rustysplit]

Fear not , Gina!!

Remember the 6p's....

Prior Preparation Prevents P--s Poor Performance

When those clouds blow over you will be laughing.

[Gina]

Thank you for that

[Flying Eye]

Must say that with so little clear weather I'm beginning to wonder if all this preparation for what just might be is one gigantic waste of time and money Am I in the wrong part of the world??!!

Chin up, it's just going through a grumpy patch, it has to do this to balance the books for the really good spell we had back on Jan 13th and for a few days thereafter.

[Gina]

That's true The forecast is for a clear night here but there's a lot of cloud to shift first!! Still you never know

[Gina]

Wonders will never cease - low and behold - a clear night. Slim crescent moon with Venus nearby and Jupiter not far off. Mars low in the east.

Anyway... been testing the finder-guider webcam. I was able to focus using the objective lens. Covers about 2 moon diameters. The moon and planets came on screen as I slewed to them with CdC. With the exposure turned to minimum the moon and planets were still grossly overexposed. Moved onto various stars and nothing. So I upped the exposure and the brighter stars were showing. As it slews I've seen other stars shoot across the frame. But the sensitivity is not high enough to show many stars. I slewed to M42 and picked up nothing! I can see the main stars of the Orion constellation but not the stars in the middle of M42.

I don't think it's looking very promising as a guider. I can't think what I'm doing wrong - other seem to be able to use this combination.

[Flying Eye]

I know it's counter intuitive, but set exposure to auto, and this allows backlight comp to start doing things, then set that higher and higher over say 20 seconds or so, there is typically some lag as it's effect comes into play I've noticed.

As long as it's just stars you're after it probably won't matter quite so badly about overexposure, that's only going to matter for planets anyway. Can put contrast up or down to suit, and set brightness high enough to see more, but not enough to bring too much noise out to play.

Use sharpness to pseudo replace the contrast you may need to lose to get the image bright enough.

This is just ideas off the top of my head from things I have noticed about how the cam seems to work.

I'd try this on Jupiter right now myself with the binoculars but the wire on the cam is just not quite long enough!

I may try mars in a bit, but light cloud is spotting in sporadically here, and I have some tripod issues sill left to address (parts in post!)

[Reggie]

Doesn't PHD have a version where it will 'stack' frames into the length of guiding frame you actually want? I'm pretty sure there used to be a version like that? 'Windows wdm style webcam camera' is the one to select I believe. Either that or it's the 'Windows VFW-style webcam camera (older & SAC8)'. So set the camera to the lowest framerate possible and it should give you it's longest exposure and stack them once it's got up to say 2s worth of exposures.

[samtheeagle]

That sounds like a bit of a let down Gina About the only thing I can suggest is making sure that you've got the focus absolutely perfect... When it comes to picking up the faint stars you need to be spot on, otherwise they just dissolve into the background.

My testing of this camera is limited to a couple of attempts so far, with one of the targets being the Rosette nebula. I've just fired up Stellarium, and adjusting the FOV to match around about what I think the finder guider has the brightest stars in the area are ~4.5 magnitude, which PHD picked up comfortably. M42 has similarly bright stars, so I would have thought you should have detected something...

[Gina]

I know it's counter intuitive, but set exposure to auto, and this allows backlight comp to start doing things, then set that higher and higher over say 20 seconds or so, there is typically some lag as it's effect comes into play I've noticed.

I see - thank you I didn't think of leaving it on auto for a long time - I guess it didn't have time, I did try it but didn't seem any better than setting the exposure to max. I'll try that next time we get a clear night.

As long as it's just stars you're after it probably won't matter quite so badly about overexposure, that's only going to matter for planets anyway. Can put contrast up or down to suit, and set brightness high enough to see more, but not enough to bring too much noise out to play.

Yes, I tried that to the point where the noise appeared.

Use sharpness to pseudo replace the contrast you may need to lose to get the image bright enough.

Don't think I tried that but not sure now - I tried most things. I'll try that too.

This is just ideas off the top of my head from things I have noticed about how the cam seems to work.

I'd try this on Jupiter right now myself with the binoculars but the wire on the cam is just not quite long enough!

Ah yes, know that problem I had no problem with Jupiter other than grossly overexposed.

I may try mars in a bit, but light cloud is spotting in sporadically here, and I have some tripod issues sill left to address (parts in post!)

It picked up Mars with no problem - again grossly overexposed even at minimum exposure. Just produced a small fuzzy red dot. I might try an IR blocking filter another night - should be able to focus better. Shouldn't matter for tracking as a slightly wider image is wanted for guiding, I'm told - covering several pixels, and the extra sensitivity to NIR should bring in more stars.

So, a few things to try next time - thanks