Looking for a scope + tracker

[Catanonia]

New to the hobby and have been reading alot.

Are Meade 90 ETX 125 ETX Premium editions any good for astrophotograhy of DSO ?

Can they easily be fitted with a DSLR (A700) ?

What is the auto tracking like on them ?


I like the Goto functionality of them, just curious as you your views.

Bearing in mind I can get one for about $600 new in the UK and I am looking to take some colourful pictures of DSO with stacking.

Obviously a German mount and a 'proper' scope would be ideal, but I haven't the money for that.

Thanks

Cat

[chris.bailey]

If you look around there are plenty of people who have imaged with the ETX series. They are however very slow in optical terms (f15) and as you are limited to ALT AZ tracking your exposures will be a maximum of around 30 seconds or so before field rotation kick in. You will ideally need a focal reducer to image with it ( a 0.63 FR would get you down to F10 and a more manageable focal length). Fitting a DLSR is no major problem but they are susceptible to balance issues and you would be far better of using a light CCD unless you buy some balance weights. The Autostar GOTO is very good and they are pretty easy to setup.

You can add a wedge to an ETX but that does add some complexity to set up. That would howver get you the 3-4 minute exposures you ideally need.

DSLR adapters, balance weights and wedge here. Adds around £300 to the base price of the ETX though. For that total you can get an EQ5 and a decent 80mm imaging scope.
http://www.astro-engineering.com/ETX/etx90105125.html

[chris.bailey]

Another option would be an Astrotrac. About the right price and simple to use with existing lenses. I think you would find it a much easier solution.

[Catanonia]

Another option would be an Astrotrac. About the right price and simple to use with existing lenses. I think you would find it a much easier solution.


Ah so the Meades ETX are not equitorial mounts then... Been trying to work that one out.



Yeah been looking at the AstroTac, nice idea, so clever.

I would need to get a ball joint for my tripod. £475 is a lot just for a mount portable mount when I am sure you can get a decent mount / scope combo.

Need to keep an eye out for AstroTrac sales.

Thanks guys.

[chris.bailey]

Nope, the ETX's are very much Alt Az though you can get a wedge for them but by the time you accessorise one for decent imaging you could get say an HEQ5 and an ED80!

I would not dismiss the Atrotrac. I borrowed one for a couple of weeks and 5 or 6 minute decent exposures are not a major issue. You have got a couple of decent lenses so they would work. I successfully mounted a Williams Optics ZS 70 on the Astrotrac. Its a lot more mount for the money than spending the same on a GEM say and HEq5 or EQ6.

[A.S.I.G.N. Observatory]

For a fork mounted scope (or alt-az) a star traveling on a curve would have to be tracked in steps. Up>across>up>across>down>across>down>across.

A fork mounted scope on a wedge, turns the across motion (left-right) into a right ascension motion, requiring only one rotational range of motion (one motor drive) to track a given star along it's curve. To set the wedge, it is lifted on an angle to match your latitude on earth, then rotated north/south/east/west/ to line up with celestial north or south, depending if you ar in the northern or southern hemisphere.

In my humble opinion, to start with an alt-az mount is already a disadvantage, which has to be corrected with more toys (money) A German Equatorial mount is by far the best option, so why not aim for that. I am routinely shooting 15 minute subs with perfectly round stars.

While I was restricted to my very large fork mounted telescope, I did write a page on alignment procedures. I hope it helps.

http://www.asignobservatory.com/drift_alignment.aspx

Baz.