Philips SPC900 or SPC1330 ?

[Zaphod_B]

Hello Everyone

First post about CCD imaging. Just had a quick trawl through this thread and can't find anything on this so here goes ...

One of the current faves is the Philips SPC900 webcam as a fairly cheap but very good CCD imager. It has 1.3mp, 90 frames per second and colour.

This now seems to be out of stock at so many places (in the UK) so is the SPC1330 a better bet? This has 2mp, 90 frames per second and colour.

Does anyone have any experience of this webcam as a basic imager? These are widely available and about the same cost as the SPC900.

Does the SPC1330 have the same threaded fitting as the SPC900?

Thanks in advance

Zaph

[Dave Smith]

I don't know about the 1330 but I have just today received an SPC900 from Pixmania so they are available.

Dave

[Zaphod_B]

Yes, thanks Dave, I'd seen that (£34.90 +£5.30 p&p).

I was just checking before I ordered one as the SPC900 is 3-yr old technology.

Zaph

[Parallax]

The SPC900 has a CCD sensor whereas the SPC1330 has a CMOS sensor.

CCD's are better for this hobby as they are more sensitive than CMOS.

Also, the 900 is only 648 x 480 pixels (300K). I don't know how Philips can call it a 1.3mp camera.

It's still the best webcam though for astronomy.

I suspect that the 1330 is also not 2mp (although I may be wrong).

Steve

[Ant]

Don't automatically dismiss the CMOS sensor.

The Canon dSLR's have CMOS sensors and they are about the best you can get (within dSLR ranges) for astro.

Cheers

Ant

[waynezilla]

Sorry to butt in ...

Do people generally modify the SPC900 for astro use ? The reason I ask is that I'm in the process of doing the SC1 (long exposure) mod to an ancient DLink Netqam 350 I had knocking about.

If I make a pigs ear of it, I may need to source another webcam for some cheap and cheerful imaging..

Cheers

Wayne M

[Dave Smith]

Also, the 900 is only 648 x 480 pixels (300K). I don't know how Philips can call it a 1.3mp camera.

Steve

In single shot mode (snapshot) it is 1280 x 960 pixels = 1.2288 Mp hence the claim.

Do people generally modify the SPC900 for astro use ?

Wayne M

I believe so. One of my astroclub members has recently modded one.

Dave

[Reggie]

These days its a philips spc900nc webcam that gets modified, although these are disappearing as they are an end of life product now, it used to be the philips toucam, a certain model/s of logitech webcam but they disappeared long ago.

Don't worry too much about making a pigs ear of the mod to your existing webcam (apart from the cost of replacing which isn't huge on a modest budget) as the SPC900NC mod is by far and away the easiest by all accounts. a handful of solder points and no cutting/lifting pins on the ccd either, I've done the spc900nc mod myself with limited soldering skills and it is pretty simple.

Going back to the 1330 (is it a 1330 or should it be a spc1300?) anyhoo, whilst it may be a better sensor, it hasn't been modified for astro work, so no long exposure mods exist for this webcam, it would really only be a lunar/planetary cam and your mileage will vary on how it performs as a guidecam, where long exposure would be desireable, that having been said, programs like phd will attempt to stack short exposures on the fly to give the impression of a long exposure guide image but its no substitute for a real 2second exposure.

[Merlin66]

For all the above reasons, and the fact it's still pretty "main stream" for astrowork, go for the spc900.

[Zaphod_B]

These days its a philips spc900nc webcam that gets modified, although these are disappearing as they are an end of life product now, it used to be the philips toucam, a certain model/s of logitech webcam but they disappeared long ago.

Don't worry too much about making a pigs ear of the mod to your existing webcam (apart from the cost of replacing which isn't huge on a modest budget) as the SPC900NC mod is by far and away the easiest by all accounts. a handful of solder points and no cutting/lifting pins on the ccd either, I've done the spc900nc mod myself with limited soldering skills and it is pretty simple.

Hi Reggie

Apart from the mod on the nosepiece of the webcam, I wasn't aware that the SPC900/Toucam needed an electrical mod of any kind. Can you be more specific (or PM me / post a link) please?

Cheers

Zaph

[waynezilla]

I found a page outlining the SC1 mod for the SPC900 here :- http://home.zonnet.nl/m.m.j.meijer/D_I_Y/spc900nc.htm

I dont know if you are familiar with the mods which can be applied to web cams. They are called SC after Steve Chambers who first did it. Have a look at his page here :-

http://www.pmdo.com/wintro.htm

You may not have to do anything depending on how you intend to use it i.e lunar imager or DSO/guidecam.

I'm still trying to get my head around all this too, so I hope I'm not feeding you duff information!

Wayne

[Parallax]

Also, the 900 is only 648 x 480 pixels (300K). I don't know how Philips can call it a 1.3mp camera.

Steve

In single shot mode (snapshot) it is 1280 x 960 pixels = 1.2288 Mp hence the claim.

I woke up last night with this subject playing on my mind.

In video mode, which is 640 x 480 at best, "I think" that the resultant image is binned 2x2 from the 1280 x 960. In other words, each pixel in the image is made up from a block of 4 (2x2) pixels in the CCD. This gives a higher sensitivity in low light conditions at the expense of resolution.

I may still be wrong, so feel free to correct me.

Steve

[Zaphod_B]

I found a page outlining the SC1 mod for the SPC900 here :- http://home.zonnet.nl/m.m.j.meijer/D_I_Y/spc900nc.htm

I dont know if you are familiar with the mods which can be applied to web cams. They are called SC after Steve Chambers who first did it. Have a look at his page here :-

http://www.pmdo.com/wintro.htm

You may not have to do anything depending on how you intend to use it i.e lunar imager or DSO/guidecam.

Wayne

Hi Wayne

Thanks for the links. It looks like you only have to modify the webcams if you want to do DSO imaging and have to cool the CCD.

Otherwise for planetary work and the brighter DSO's you only need to alter the nosepiece?

Zaph (who's also trying to get his head around this)

[Merlin66]

You've mentioned twice in the posts now, about modifying the nosepiece for the spc900. I have one and it uses the standard 1.25" to C thread adaptor. What mods are you considering????

[Zaphod_B]

Hi Merlin

Whilst "modding" may be going a bit OTT on the explanation, the SPC900 isn't used straight out of the box. The lens (which incorporates an IR cut filter) has to be prised off the unit and the appropriate adapter screwed into the webcam to allow it to mate with an EP holder as I hope these pictures shows clearly:

(click to enlarge)

Picture courtesey of: http://www.robertreeves.com/900NC.htm

As it isn't used in standard form, that's "modding" isn't it - particularly as the IR cut filter has been removed.

Zaph

[Merlin66]

OK.

I think most of us expect to fit a 1.25" adaptor to make it and any other webcam fit the telescope.

[Zaphod_B]

Merlin

As I said, perhaps I was being a bit pedantic using the term "modding". You're spot-on of course when you say that we should expect to fit an adapter of some sort - after all I don't consider my 400D modded when I stick it on a T-mount :oops:

By removing the combined lens/IR filter assembly this is modding in a more real sense surely? BTW it appears that having removed the combined lens/IR filter from in front of the CCD, you need to add an IR filter into the lightpath as CCDs are over-sensitive in the IR region.

This is all theoretical for me at the moment as I only ordered a SPC900 this morning - I'm just trying to get my head aroud what I need to do to get it up & working so that as soon as the weather breaks and I've got the webcam, I can have a go at imaging / stacking etc.

Still going through a pretty steep learning-curve here.

Any advice is gratefully received.

Cheers

Zaph

[Dave Smith]

Have you noticed that there is a very good tutorial on this by MartinB in Astropedia.

Dave

[Zaphod_B]

Have you noticed that there is a very good tutorial on this by MartinB in Astropedia.

Dave

Hi Dave

No I hadn't.

Thanks - will take a look now.

EDIT: Here's a link for anyone viewing this thread that is interested:

http://stargazerslounge.com/index.php/topic,3523.0.html

The link seems to be a bit "fritzy". If the link doesn't work, navigate to:

Newcomer's Zone > Primers & Tutorials > Primer - planetary imaging with a Toucam

Zaph

[Reggie]

OK guys, here's the skinny on the electrical mods for the spc900nc, there are a number of mods that you can do, the main 2 being 'Long Exposure' aka the LX mod and The Amp Off mod. Neither of these are needed to use the camera out of the box as a lunar/planetary camera, your mileage will vary depending on the DSO but make sure its nice and bright as the longest exposure you can expect is 200ms without modding. So you guys that have bought spc900ncs can use them straight away, however you should have a read about the mod in the link waynezilla posted as it may help you in the future when you are more comfortable with imaging and will save you money at the same time if you decide to mod it yourself.

The long exposure mod consists of bending a couple of pins (the spc900nc is made up of 2 boards that plug into each other) a very minimal circuit involvlng a small chip and a couple of resistors and 2-3 solder points on the board itself. What this mod allows you to do is increase the exposure time from 200ms to XXseconds, the XX will vary due to weather conditions on the night, the colder it is the longer you'll be able to expose the image before 'Amp Glow' ruins the image. The mod itself should cost no more than £10-15 depending on where you source your parts and as long as you own all the tools needed to complete the task.

Doing the mod allows you to turn your lunar/planetary imager into something a little more special, you can now take images of much fainter DSO and you can now use your humble little webcam as a guidecam for another scope + better astro camera, you are looking at £100+ for a modest retail guidecam alone.

For those that don't know, a guidecam is used in astrophotography to keep your main imaging telescope pointing in *exactly* the same place over the course of an imaging session. It's usually attached to a second telescope that is also attached to the same mount the imaging scope is on.

This allows you to take much longer exposures without getting star trails due to errors in the gears on your mount, it also has the added effect of helping you to increase the signal to noise ratio(cleaner images) in your images, as well as allowing you to capture parts of DSO that aren't(and will never become) apparent in shorter length exposures.

Now for the 2nd mod, Amp Off, this mod is a little more complicated, its usually done in conjunction with the LX mod (either at the same time or at a later date) I haven't done this mod myself as I don't see a pressing need for it myself at the moment, the effects of this mod are to reduce amp glow on the resulting long exposure images taken on an LX modded webcam. amp glow is an effect caused by heat build up in the amplifier for the ccd sensor and looks a little bit like stray light creeping into an image, the longer the exposure the more amp glow will be seen.

So, just a quick recap, the SPC900NC can be used out of the box as a simple planetary/lunar/bright DSO camera, it will also manage to guide on bright stars, so in its own right it is very versatile, the mods that you can do at a later date for a small sum of money will gain you a camera with features of £100+ cameras + all of the software for it is free.

My advice to anyone with an SPC900NC that is also a beginner at astrophotography would be to start using it, get a feel for what it can do, which will in turn give you more of an idea of what you want to do with your kit, then decide where you want to go from there.

[russ]

The SPC1330 is a proper 2mp CMOS sensor, so it's not interpolated up from VGA or 1.3mp. Philips give it a sensitivity rating of <2lux. So it's not quite as sensitive as the SPC900, which is <1lux.

The main problem is the SPC1330 is still only USB1.1 but USB2.0 compatible. Which will mean for best quality and least compression the frame rate will have to be dropped right down. Absolutely no chance of getting anywhere near the quoted 90fps. More like 5-10fps. This off course applies to the SPC900 as well. A rotten ploy by Philips (and all other manufacturers) who use the term 'USB2.0 compatiable' as a selling point. Most poeple will take that as being a USB2.0 device when it's not.

I think the SPC1330 would be interesting lunar imager with its larger chip and it's more sensitive than most CMOS equipped webcams.

[Reggie]

Yes, given the specs, as a lunar/planetary imager it may do quite well, another interesting webcam along those lines is the Trust WB-5400, which I believe is the same size sensor as the 1330, I've used it as a lunar webcam and its very useable, not as versatile as teh spc900nc though as its a non-modded cam.

The other interesting thing about the trust cam is that whilst its not electronically modded there have been some interesting developments on the software control side of things, Not sure if many of you are aware of the 3rd party webcam control applications that have been written for the spc900nc, they allow independent control of the webcams functions and also allow you to load astro friendly modified firmware onto the cam. the control software WcCtrl also allows you to control the trust wb-5400 and they have made software modifications to allow the user to have longer exposures, up to about 1.4seconds.

[Merlin66]

You should be aware, to do the LX mods as described by Reggie, you also need a Serial/ Parallel connection to the camera to provide the control signal. With some modern laptops this can involve additional costs of a USB>Serial ( Keyspan's the BEST) or a USB > parallel ( must be bi-directional; not all the cheap ones are!)

[Zaphod_B]

Thank you reggie, rus and merlin66 for the helpful posts.

The webcam arrived this morning and I have to say that so far I am impressed with Pixmania.com.

Now all I have to do is figure out what I have to do to get it all up & working.

For example, what do I install off the CD that came with the webcam? The drivers, obviously but do

I need to install anything else?

I have downloaded RegiStax v4 (v5 is on the way and is in Beta at the moment). Is this all that I

need to begin astro-imaging with the SPC900?

Any other hints, tips & suggestions (eg software) would be gratefully received & appreciated.

Thanks in advance

Zaph

[JohnC]

i use the same cam and use wxastrocapture to grab the files.

http://arnholm.org/astro/software/wxAstroCapture/

Best regards

John