Essentials of Webcam Autoguiding.

Dave L: There's no doubt that if you want a 'black box' solution to autoguiding then the ST4 is unbeatable. However these are getting harder to find and are not getting any cheaper when they do come up. If you get one for around 500euro, I think you will be doing well. The benefits of the ST4 over the webcam/laptop option as I see it are, no pc required in the field, no need to modify webcams. Realistically, a PC or laptop is going to be required for other stuff such as controlling the imaging camera anyway, so that benefit gets knocked on the head.

There are even a copuple of downsides to the ST4 option. You have another device that requires a power source. Unless your prepared to bauy big money for the new STV then you dont see your guide star, you have to interpret numerically what the camera is seeing. This is not a real problem when your experienced with it, but for a new user this could be daunting. I love being able to see the guide star on screen, focus and guide visually.

The cost thing is a big one. Considering that toucams can be got for around 50euro, add a tenner to that for the bits you need to modify it. (assuming you have a decent solder iron etc already). Depending on the scope you have you can run up a cable to connect your pc to the scope for next to nothing. You could go the shoestring adaptor route (which in myt experience is superiour, but does add an extra 60 - 80 euro or so to the cost). SO theres no doubt the webcam route cant be beat for cost. And it will perform just as well as an ST4. With the advent of programs like guidemaster its clear astrophotographers are embracing this method.

I'd just add another thing, I kinda get the feeling sometimes that the process of modding webcams is shrouded in some kind of mysticism. People thinking that its too hard to do. I'd be lying if I said it was a doddle, but I would say that its easy enough for anyone who can follow instructions. It turns out that in fact toucams are hard to break. Considering some of the abuse I've given them while hacking away with a soldering iron, i'm amazed that I've never magaged to break one yet (famous last words).

When I build this new camera, i'll be writing an article in which I will explain a new technigue I've developed which completely avoids having to solder to those tiny pins on the toucam board. I've come up with a much better way to do attach those wires. I wont go into it now as the article will explain it all. My hope is that when people read this article they'll say to themselves, yes I can do that!

I know this is a shameless plug for the webcam route and sorry for making this post so long.

Dave L: There's no doubt that if you want a 'black box' solution to autoguiding then the ST4 is unbeatable. However these are getting harder to find and are not getting any cheaper when they do come up. If you get one for around 500euro, I think you will be doing well.

I've one on the way from the US, I expect to have it when I arrive back from Turkey.

The benefits of the ST4 over the webcam/laptop option as I see it are, no pc required in the field, no need to modify webcams. Realistically, a PC or laptop is going to be required for other stuff such as controlling the imaging camera anyway, so that benefit gets knocked on the head.

Since I have an observatory setup that includes a PC, so this is not a problem.

There are even a copuple of downsides to the ST4 option. You have another device that requires a power source.

again not a problem for me in the observatory setup.

Unless your prepared to bauy big money for the
new STV then you dont see your guide star, you have to interpret numerically what the camera is seeing. This is not a real problem when your experienced with it, but for a new user this could be daunting. I love being able to see the guide star on screen, focus and guide visually.

I chose to get the optional flipmirror with parafocal eyepiece for centerinng, this significantly eases the use of the st4.

The cost thing is a big one. Considering that toucams can be got for around 50euro, add a tenner to that for the bits you need to modify it. (assuming you have a decent solder iron etc already). Depending on the scope you have you can run up a cable to connect your pc to the scope for next to nothing. You could go the shoestring adaptor route (which in myt experience is superiour, but does add an extra 60 - 80 euro or so to the cost). SO theres no doubt the webcam route cant be beat for cost. And it will perform just as well as an ST4. With the advent of programs like guidemaster its clear astrophotographers are embracing this method.

Yea, if I were going to route of the webcam, that adapter would be definitely the way to go and the cost cant be beat.

I'd just add another thing, I kinda get the feeling sometimes that the process of modding webcams is shrouded in some kind of mysticism. People thinking that its too hard to do. I'd be lying if I said it was a doddle, but I would say that its easy enough for anyone who can follow instructions. It turns out that in fact toucams are hard to break. Considering some of the abuse I've given them while hacking away with a soldering iron, i'm amazed that I've never magaged to break one yet (famous last words).

I've years of experiance with the soldering iron, the toucam mod is mechanically intricate but electricially trivial.

I know this is a shameless plug for the webcam route and sorry for making this post so long.

not a problem , its good that people see that there is more then one way of cracking a nut.

One thing I like about the st-4 is that it can learn the axis amoungst other features, in that the camera does not need to be perfectly horizontal with the horizon at the meridian, the st-4 can learn this, programs like guidedog cannot, altough I'd bet its on the way if not here with other programs, its just that I want the thing to work and not have to be endlessly fidgeting with an unproven setup.

One thing I like about the st-4 is that it can learn the axis amoungst other features, in that the camera does not need to be perfectly horizontal with the horizon at the meridian, the st-4 can learn this, programs like guidedog cannot, altough I'd bet its on the way if not here with other programs, its just that I want the thing to work and not have to be endlessly fidgeting with an unproven setup.

Dave, best of luck with the new ST4. I cant wait to see what you acheive with it.

Yep your're right, this functionality is now availiable in guidemaster. See this thread;

irishastronomy.org/boards/viewtopic.php?t=3853

guidemaster does exactly what the ST4 does, even figures out what guide rate and backlash your mount has!! In fact I think they copied the ST4 model for autoguiding, as did maxim DSLR. The difference being that guidemaster is free!! TBH, even with guidedog all that was involved was placing the camera with the long axis of the chip perpendicular to the dec axis, so it really wasnt much of a problem. At the end of the day, any autoguiding system will only perform as well as your mount an local conditions (wind etc) will allow it to.

I'd just point out that the webcam route is now well proven, there are countless astrophotographers using this method.

Your right also that its good to have a couple of people who can comment on the merits/demerits of various approaches. Maybe when you get a bit of practice with your new ST4 we can get together and write up an article on exactly that subject.

Dave,
No problem , I'll post up a big review of it in the products review section when I get to grips with it. I've been scanning the web for good and bad comments about it and found mostly good reviews, if it turns out its the reviews are a load of hype, I'll be the first to flag it and you'll be seeing a big add on astromart for it :lol: but hopefully it wont come to that.

Dave,

I'm 100% sure the ST4 is well up to it, its the tool for the job. Really I just wanted to flag the fact that the mount and local conditions play almost as vital a part as the autoguider.

I think this is one ST4 we wont be seeing up on astromart anytime soon (not until you've saved up for the STV anyway

Dave - ST4 for sale in UK. Well, it was a few days back.... stg 250

www.astronomy-uk.co.uk/viewtopic.php?t=2539

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Cheers

Dave