Webcam Images

bharat · Post by **bharat** » Mon Jun 28, 2010 10:52 am

Yesterday, I did my first little experiment in webcam photography with my Omni 150X.

Made a makeshift webcam adapter out of an old 35mm film plastic container, mounted my $20 something Creative notebook cam (VF0470) (CMOS sensor, 15fps). Focused the scope on the top of a distant crane boom from my window and managed to get a decent footage of the crane boom top. (Much more magnification than with a 25mm eyepiece).

Although my webcam may hardly be suited for astrophotography, I am going to try to make an attempt at taking some lunar pictures. Naturally, I have a few doubts/questions:

1. Are lunar pictures possible with a basic webcam as mine? This is just for trying out. I don't expect to get great pictures, but it will be ok as long as the moon looks like the moon and not a cotton ball! The webcam software does not have too many adjustments for the controlling parameters though.

2. I do not have a motor drive for now. Are lunar pictures possible without tracking ability, considering that the exposure time will not be too long?

3. With my yesterday's experiment, I tried stacking & processing using Registrax. It worked in the sense that the software ran as intended and resulted in a final image. But given that the picture taken was not so challenging, there was'nt much difference between the original and the processed image. I went through the Registrax process without really understanding what is going on. Is there any information on the web where the image processing terminology such as image alignment, stacking are explained in very simple words. (like what is image alignment used for?, what exactly is stacking?).

Thanks in advance for your responses!

orly_andico · Post by **orly_andico** » Mon Jun 28, 2010 11:16 am

1. Yes, I even did some Mars web camming during the 2003 opposition with a by-modern-standards primitive Intel web cam. You may find that the web cam has trouble reaching focus on your Newtonian (how far was the crane? if it was > 200m then should be OK)

2. Yes it is possible if you keep the magnification low. At 100X plus, the moon drifts across the FOV so fast (order of 10-15 seconds) that you can't get enough frames for Registax to work with.

3. I have no idea!! I've been web camming Jupiter the past couple nights and frankly Registax is not giving me any love. My results are exactly like yours -- the final result is just "cleaner" (no noise or dust blobs) but it's nowhere near what I see on the internet. Granted part of that is my bad focusing skills...

Another thing is, the moon is so large that your web cam will only cover a tiny fraction of it. So pick your crater and have at it... (see for example the work of Wesley Higgins.

For whole-disk images, believe it or not a DSLR will match a web cam (the pixel pitch is about the same, but the DSLR sensor is far larger). You'd need a 2" focuser though, not sure if the Omni has that.. and there will be huge edge-of-field vignetting because most Newtonians aren't built to illuminate a full DSLR sensor. So for the moon, the only "advantage" I see for the web cam is you can stack like crazy and defeat the seeing.

bharat · Post by **bharat** » Mon Jun 28, 2010 1:08 pm

orly_andico wrote:1. Yes, I even did some Mars web camming during the 2003 opposition with a by-modern-standards primitive Intel web cam. You may find that the web cam has trouble reaching focus on your Newtonian (how far was the crane? if it was > 200m then should be OK)

Distance was approx 500m

2. Yes it is possible if you keep the magnification low. At 100X plus, the moon drifts across the FOV so fast (order of 10-15 seconds) that you can't get enough frames for Registax to work with.

Is there a way to control the magnification with a webcam?

orly_andico · Post by **orly_andico** » Mon Jun 28, 2010 3:18 pm

Well the web cam is normally used "prime focus" -- you have to un-screw the existing lens of the web cam. The only way to vary the magnification is to put a barlow in there.

On the other hand, you could do "afocal" imaging -- use the web cam with its existing lens in place, and find a way to couple it to your existing eyepiece(s). that way changing the eyepieces will change the magnification.

timatworksg · Post by **timatworksg** » Mon Jun 28, 2010 9:51 pm

Mostly, the webcam has the lens removed, which means dismantling it and removing the lens part, leaving the exposed chip. The 35mm film canister is then glued or if it fits well...great! I did one before and had to glue it..lol! Then its done at Prime...slotted in place of your EP, or into a barlow for extra Mag! For planetary, rather than stills you take a 2-3min (if I'm correct or was it longer??..) video and let the moon drift off view basically. You can recenter and record again. Then take all those vidz and Registax will open the file up as lots (hundreds!! hehe) of individual frames! It will choose the best and align and stack for you! I believe there are loads of other software available...do a Google on Webcam Astrophotography software and a fair bit will turn up! Then its a case of choosing the best. I did try it before and took some 3-4mins of movie...tracking with the slo-mo cable, with vibration and all....but there will still be a good number of clear images to choose from.
Just need to get focus, then adjust gain settings. If your cam software has an advance tab, check that out and you can lower Exposure (however not possible with long exposure shots). Prob is, if you Barlow then by the time you look at your screen, adjust and check back...the planet zoomed away..haha! Recenter and try again!

Astrophotography can be frustrating and so much to set up and get ready for when the night can last for only so long! But the rewards can be nice at least for something you can achieve even if it's not the best!

For Afocal, if it's the moon, you can hand hold a compact Digicam at the eyepiece and shoot hand held and 1/125 or more even as the moon is preety darn bright! Prob would be trying to hand hold the digicam lens at the same plane as your EP! If it has live view then it's easier...otherwise some use another tripod and mount the cam or get one of those Afocal frames that clamp onto your EP and hold the cam.

Only thing with a normal webcam is that it doesnt have looong exposure capabilities for DSO's! So planets are cool! The moon is a great target to experiment and play around with!

And as Orly mentioned, if you get only part of the moon, focus on a crater or detailed surface and take a shot!!! You may be very pleased with the results!!

Lastly there are FREE webcam software that can run most webcams and give you more flexibility then the normal packaged one. Google again...they are there.

Also there is some software that is supposed to be able to make a webcam do long exposure for DSO's! can't remember the name....but only trhough modification is this possible,....so don't bother trying something that sounds to good to be true..lol!

Grab movie recordings and stack from there! Some webcam softwares for Astrophotography can do time lapse, motion detect (lightning) and stack at the same time.

Lastly...have fun!!! There isn't any harm trying and trying and trying. I know I am!!