Guide camera

[Ferox]

Does anyone know if there is a reasonably cheap guide camera (I'm not sure if web cams can be used or if so which would be best ).

I really can't justify the price of a QHY5 so am looking for something on the budget end of the scale to get me started.

Thanks

Andy

[steppenwolf]

Andy, when I started autoguiding, I used a Philips webcam with some success using some software called GuideDog. The problem with a webcam is that it is designed to take numerous frames per second and it does this very well but for guiding, somewhere in the region of 2 or two second exposures are ideal. A webcam normally has a slowest shutter speed of about 1/25th of a second. This can be sufficient and it can be done so you have little to lose but remember that you will still require an interface between the PC and your mount so this must be factored into the cost - the QHY5 already has this interface built in.

This page on my website may be of interest.

[centroid]

The main problem with using webcams as guide cams Andy, is the lack of sensitivity.

Normally, the imaging scope, is of a larger aperture than the guide scope, so there is already a significant difference in 'light grab'.

Realistically, the QHY5 is about the cheapest option in terms of a 'proper' guide cam. Even then its' not as sensitive as say a Meade DSI (albeit not strictly a guide cam, but does work very well in the role).

An SC modified webcam, would be better than a 'bog standard' webcam, but it would still be a compromise as a guide cam.

My advice, would be to 'shop around' for a second hand DSI-C, or QHY5. I say DSI-C, as these were the first ones available, and as such would be the cheapest.

BTW, I used a DSI-C as my guide cam for quite some time, and it worked very well.

HTH.

Dave

[Ferox]

Thanks Steve and Dave,

Sort of what I expected to hear but was just hoping there might be a cheaper alternative.

Oh well I suppose I better start looking for a second hand cam,

anyone know of a bargain waiting to be snapped up?

[Reggie]

In general the only webcams that are well suited to guiding are the astronomy moddable ones, philips toucams (spc900nc), some logitech models. With a little cash outlay and some soldering skill you can turn a £35 webcam into a long exposure guiding cam that will work with all of the free guiding applications.

Alternatively, you could try using a trust wb-5400 this can achieve a 1.4s exposure using software control only (via the wcrctrl application).

[jgs001]

Andy, according to PHD, it can use a normal webcam, like an unmodded SPC900, and it does this by taking a sequence of images and stacking them on the fly. As I've not got going with guiding yet, I can't confirm how well if at all it works.

[Roy Batty]

Andy, according to PHD, it can use a normal webcam, like an unmodded SPC900, and it does this by taking a sequence of images and stacking them on the fly. As I've not got going with guiding yet, I can't confirm how well if at all it works.

John's right, you can use a an unmodded web cam in PHD but the reason I moved on to using a QHY5 is that the chip size is also small on a webcam, typically 1/4 size - with a QHY5 it's 4X the size! plus alot more sensitive as already mentioned.

Keith

[Reggie]

I've just started using the qhy5 over a modded spc900nc myself, leaps and bounds better in terms of everthing really, I was shocked to see M82 on phd with a 1sec exposure. It was faint and fuzzy but no problems telling whether my goto was accurate

[ollypenrice]

I use Atik 16ic cameras and while these are pricey new, by guidecam standards, they turn up second hand as folks upgrade. It is a dream of a guide camera. You never have to look far a star if using a fast guidescope. Guiding is quite hard to master so giving yourself a fighting chance to start with would be my two penn'orth.

Olly.

[beamish]

And Reggie even took a screen shot !! Guess it's all working nicely now !

I too have recently bought a QHY5 specifically to guide with, as opposed to trying with a webcam. Like Olly said, it can be done but the difference in sensitivity between the two is enormous .

Karlo

[Reggie]

It's definitely working, just not on my intended target kit (my laptop that has been with me since the start of my astronomy) I've got it all running on a socket 478 P4 2.4Ghz cpu, 1GB ddr400 ram and a cruddy old PCI ati rage graphics card, it ran incredibly smoothly, I really do need to grab a cheap AGP card though so I can run stellarium/SN as running 2 computers where 1 will do is not my idea of fun.

[Ferox]

Thanks everyone,

I've pretty much decided not to go the web cam route as I know I'll only want to upgrade to a better cam eventually anyway.

I guess the thing to do is start saving and keep a look out for a second hand one.

Andy