Is mine a large one or a small one?

Dave - there is always a trade-off!

And by the way, for the biggest scope with best CDD to work, you'd better plan to move to a dark site with very good seeing.

Scopes with short focal lengths are less affected by seeing so you can image and view on more nights with better results than a scope with a long focal length (hence the proliferation of focal reducers).

Of course, the longer focal lengths give you better magnification and therefore more targets. A small focal length will show saturn as a mere dot (which I know has many amateurs disappointed), a larger focal length will give you a bigger view of the planet, but you are more affected by seeing conditions.

You can of course improve matters by using reducers, Barlows, moving to Hawaii!

CCD cameras seem to be improving all the time. And DSLR's are coming on a treat now that manufacturers have seen that astronomers could be another group to cater for. As far as price goes, you can pay a little, a lot or an extortionate amount of money. I have the Meade DSI and am very happy with it. At 299 dollars, its about a quarter of the price of the likes of SBIG and Finger Lakes CCD's and it images just fine - for now. I'd hope to upgrade after I've really learned the trade - which will hopefully be at the same time as my savings account is bulging.

Trade-offs are the order of the day though. The larger and more complex CCD's will only 'work' with the more precise instrumentation available (mounts and scopes). You need a top end mount with a top end camera. Get a top end camera and slap it on a so-so mount and you're wasting your time.

Small scopes, so-so mounts and cheap CCD cameras give great wide-field images - OK, you won't be imaging the cone in the cone nebula but shots of constellations, the Milky Way, large clusters etc will be quality images.

When the weather improves, I'm hoping to spend time imaging with the ETX70 and get some of those great wide field shots and post them here. Or I'll be moving to Hawaii!

Cheers

Dave McD

Dave,
It might be abit cheaper to get a barlow then move to Hawaii

Well said Dave,

I've just started imaging with my own ETX-70, but the results aren't up to much yet. it's been so windy and cloudy recently I can't seem to get a break! Would be interesting to exchange notes if we get around to meeting up in the Keadeen.
One good quality piece of hardware at a time then

As for scope size, sometimes you can just get lucky with hawaiin style visibility conditions that will let you get the most even out of a small scope- role on the Springtime!

When I started with the DSI, my images were atrocious. It really is a steep learning curve - and I had been reading about CCD imaging for nearly a year at that point! I thought it'd be a breeze - boy did I think wrong!

Youu're dead right about the quality hardware. One-at-a-time, unless you win the lottery.

The most critical item for imaging is the mount. The longer your focal length, the more critical it is. The ETX70, whilst it seems to have reasonable tracking, suffers from two issues:

1. The tripod is not very stable. To make it better, hang a couple of bricks in a plastic back from the hook underneath the accessory tray. I found it stabilises the mount a good bit.
2. Alt-Az - you'll get field rotation in your images. The solution is to obtain an equatorial wedge - the scope will work on a wedge, its in the setup on the hand-controller. I think there may be some comercial models available but you can make one. I've nearly finished mine - when its done I'll post details.

When the weather clears up, I intend to give the ETX70/DSI a good run for its money. I've recently concentrated on the 8" reflector and got reasonble results. So I'm hoping to get good wide pics with the 70mm refractor.

When we get to meet up, we'll definately swap notes.

What camera are you using? Is it the toucam? If you have any pics, can you post them? No matter how cr*p they look, I'm sure I've many that are far worse!

Cheers

Dave McD

The little etx does suffer some problems alright.
The tripod is light, but I guess this is for portability, I noticed a hook on the end of the tripod where you might be able to hang a few weights to stabilise it ???

But reasonable images are possible from it, I experimented with the toucam and got an image of saturn which shows the rings and globe, not alot of detail in fairness, but lets not forget its a 70mm scope,
(barely legelly a scope if you know what I mean )

You can get deep sky images, I was able to get a one of the orion nebula with it with the canon 300D. I also got the moon this way.

One thing you need to know is......
If you put the canon in the eyepiece holder (using the flip mirror) then the field of view is barely enough for the moon, there was also noticable field curvature.
If you use the direct method (using proper adapters) I find you get a much wide field of view, something like 3 or 4 times wider with less distortion.

The images I refer to saturn, M42 and the moon are in previous posts

For all its 'problems', the ETX70 is a super little scope, at the price - anyone that got one should be very proud of it! Fantastically portable and good performance.

I stick a couple of house-bricks in a plastic bag and hang them from the tripod hook to stabilise the tripod more. I could probably hang the ruckbag from the hook - there's that many eyepieces, filters, cables and bits and bobs etc that there's be enough weight

I'm sure with a Barlow planetary images would be acceptable - I've yet to get to that point. And of course, large nebulous are a prime target - in fact, many are so big, if you used a larger scope you'd have to do a mosaic. M42 is a super target. I'm going to have a go soon and try out a number of filters.

One thing I have found is that my images suffer no noticable deterioration or change when I removed the IR filter from the DSI - the quality of the filter was poor - it was almost like the coating was handed painted on by brush - flats were the only way of removing the artifacts.

Some of the best images I have seen have been taken with 4" rafractors - so the ETX70 is definately capable of some good stuff. The gauntlet has been dropped...

Cheers

Dave McD