Advice needed - looking for an imaging scope for a gift - £500 budget

[Eddy_]

Hi,

I'm looking for a scope suitable for imaging. My budget is around £500 (can stretch a bit depending on what's available) - I'm looking for the best I can get for my money and only really know the very basics about telescopes.

I'm slightly confused about what exactly you would need to take images - I've seen motorised/computerised bases etc that seem to do object tracking, yet i've also seen that people use attached 'autoguiders' that control the telescope also.. I'm also confused by the different base types - az, eq etc..

I've seen a number of 8 inch motorised reflectors (sky watcher 200p is one) that look good, however don't come with a camera within my budget.

I have found a celestron nexstar 4se with a 'neximage' ccd camera for £499 - are these any good? is this sort of low res ccd camera only good for planetary imaging and not stars/nebulae etc, or is it the scope that limits what you can image? Is there a big difference between this 4 inch and an 8inch reflector? It would be great if I could get something that is suitable for planets and deep space stuff.

I'm realistic that I probably wont get a decent enough scope with a camera for my budget, so would be happy enough just getting a decent enough telescope/base etc that I could add imaging to in the future..

Would appreciate any advice!

Thanks.

[ollypenrice]

Hi Eddy, I'll try to give you an over-view.

There are two kinds of imaging. Lunar-solar-planetary is done with modifed webcams which are cheap and effective. You take video frames, lots of them and all of low quality, but you get so many in a couple of minutes that the laws of averaging combine them to make something wonderful.

Because your frames are sub second exposures each there is no need for accurate tracking. The frames will not align on their own but clever free softwware does that for you in a jiffy. You need only a low level mount to give the stability and tracking accuracy required and you certainly don't need an autoguider.

The telescope needed for this needs a long focal length to make the tiny planets come out at a reasonable size. A Skywatcher 127 Maksutov might be the thing. You would add a barlow lens, webcam and motorized equatorial mount.

Then there's deep sky imaging, my own thing, and there £500 doesn't get you very far I'm afraid. A quite different scope is need though, one with a short focal length and fast f ratio. Why? Because the tracking accuracy required is extreme. The longer the focal length the better it has to be and the 'slower' the f ratio the longer your exposures have to be - which puts more pressure on your guiding. So the rule on a budget, and for beginners, is 'short and fast.'

Cameras can be DSLRs either modified or standard or dedicated CCD cameras. On a budget go for a used DSLR, probably a Canon.

So far so good, small scope and cheapish camera. Now for the bad news. The mount.

They have to be accurate and unless you spend a fortune they will need to be autoguided to get beyond 2 mins. The minimum would be an HEQ5 which alone breaks your budget. Then later you would need an autoguider to get decent longer exposures.

An autoguider is a small scope and camera riding shotgun on your main scope and taking pics every second or two. When a star in this pic moves the mount is informed and recentres it PDQ.

Now do be wary of seeing mounts cheaper than the HEQ5 (Or Celestron's competitor) which seem to tick all the boxes. They have dual motor drives, Periodic Error Correction etc. But they just aren't good enough. And I really don't say that as some kind of perfectionist; it is the bottom line in my view.

The webcam idea is feasible on your budget and the sky is often good enough for that in the UK when deep sky nights are often a rare treat. That's why I came down to France...

Hope that is a help. Come back for clarification by all means. Just PM me.

Olly

[Eddy_]

Thanks that definitely helps. As i suspected i think i'll be aiming for webcam based planetary imaging for him.

[Eddy_]

Another quick question - I'm now looking at the Skymax 127 and the Explorer 200P.

I now know that the 127 is Maksutov-Cassegrain, 1500mm (f/11.81) with a 5 inch aperture whereas the 200p is 1000mm (f/5) and 8 inches.

How will the images from these two scopes differ? You've mentioned that the longer focal length will make planets appear larger etc, but how does the differing aperture sizes affect this? Is there a big difference between the mak and the newt?

Would DSOs be visible through these? I take it the 200P would be better for photography due to the fast focal ratio (assuming I got a good mount also)?

Thanks!

[brantuk]

Hi Eddie - the larger the aperture the more light you gather making dso's easier to see through a bigger scope.

The size of the object seen will vary with magnification (FL of tube divided by FL of ep).

Also bear in mind FOV - dso's tend to be large so wider fov's are useful unless you're trying to zoom in on specific areas.

Faster scopes allow for longer camera exposures so more light can fall on the sensor for longer - the only way to see some dso's.

Hope that helps

[ollypenrice]

The Mak is too slow for deep sky imaging but would be better for webcamming the planets. The Newt would be more versatile in visual use but both are good. The Mak would hold collimation better and be easier to carry about and would probably win on the planets but lose on the deep sky.

Olly

[GuillermoBarrancos]

I just saw a nice deal (well astro equipment is overpriced here. but for norway this is a good deal I guess) on Celestron Advanced C6 N GT.

I wonder what the quality of this 150mm F/5 Newt scope is, when it comes to both observation and imaging and quality of optics.

At least it comes with the CG-5 GT mount.

[Keiran]

I have a skywatcher 200p on an eq5 mount, i have taken a few pics of the moon and saturn and it was a joy i have not tried DSO's yet but please feel free to check out the photos moon and saturn and saturn.

I think it is a brilliant telescope for the price and i know that FLO does it for £378.

And ebay for the Celestron Neximage for under £90.00. I bought from this person so he is genuine. The picture of the moon and the first saturn is with my DSLR and the second saturn with the Neximage.

P.s my scope is not GOTO.

Hope that this helps abit.

Keiran:icon_salut:

[GuillermoBarrancos]

Yeah FLO is a lot cheaper then the stores here in Norway.

Unfortunately I just had a talk with FLO and they do not ship to Norway. But this kind of heavy stuff always gets intercepted by Customs and then they charge 25% tax on it. So making it a lot less interesting as well. /facepalm

The VAT rate is higher here (25% compaired to 17,5% in UK). So that explains a bit as well with the price differences.

But I think this package is pretty nice: njopsahl.no - Nettbutikk med teleskop, kikkerter, landskapskikkerter etc.

As the CG-5 GT mount is sold seperately for 8000 NOK. So I basically just pay 2000 NOK for the C6 N scope.

In the end I always have a very nice mount and can fit plenty of future scopes on it.