Meade ETX 125EC?

[jason32]

Hey guys,

I found a good deal on 125ec, the owner says the scope focuses perfectly better than most of them out there. Also he said if I use it in eq position then I'll be just using one motor so less vibrations and could actually do long exposures.

I am interested in DSO photography but cant spend £1200 at this time on heq5 and stuff.

So if I use EQ5 with SW 130PDS will that be ok? but how to track with eq5 mount? or do I really have to have heq5?

[Oddsocks]

You state that you are interested in imaging DSO's.

Using the ETX-125 for DSO imaging is going to be struggle with it's 1900mm focal length and slow optics of f/15.

Because these scopes do suffer from mirror flop this would need very good guiding using an off-axis guider or a fast active optics unit, either of which can cost as much or more than a new HEQ5 Pro or equivalent, plus a lot of luck to capture quality images.

While it would be a reasonable starter for planetary imaging with an inexpensive webcam or capturing the very small and bright planetary nebular you would soon run out of objects to image as so many of the interesting objects will be so much bigger than the ETX's field of view. Having begun my foray back into astronomy with the smaller ETX-90 I can tell you from experience that this is not a scope to consider starting out in imaging with.

Do you already have the EQ-5? if so your second choice of the SW 130PDS is an excellent scope to begin imaging with and the EQ-5 could be used with the addition of the Synscan PRO-GOTO upgrade kit for EQ-5 http://www.firstlightoptics.com/skywatcher-mounts/synscan-pro-goto-version-3-upgrade-kit-for-eq5.html

at £295, this would add controlled tracking speed, motorised GOTO in RA and DEC plus the all important ST4 guiding socket that would allow you to add a separate guide camera in the future as funds allow. For image capture a cheap second hand Canon DLSR will get you started.

If you don't already have the EQ-5 then this is a more expensive option than buying an HEQ-5 Pro or equivalent up front.

Before spending any money on scopes and mounts, and while the weather is set to continue cloudy for at least another few weeks I would get a copy of this book and read it through, it will help you to get a grip on the issues involved with imaging and guide you towards making the right choices for future investment:

http://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html

As Steve Richards explains in his book the mount is is the most important part of an imaging set up, and there is no reason why you would not get excellent results with just a good mount and a second hand DSLR mounted directly on it, with out a scope, just using the DSLR cameras standard prime lens or a second hand long length lens of around 260-380mm

If you want to, come back and post here what your budget is going to be and what equipment you already have and others may be able to offer more specific advice, and don't forget the second hand astro equipment market will give you access to substantial savings on a good used mount and/or OTA, you won't have enough posts yet to see the classified section here at SGL but the UK AstroBuySell site is always worth a daily look while searching for used equipment:

http://www.astrobuysell.com/uk/

[jason32]

I just ordered the advanced VX mount so thinking about getting the SW 130pds or 150pds.

I believe both heq5 and vx are just the same quality and guide well?

[Peter Drew]

Focusing on most Schmidt-Cassegrain or Maksutov-Cassegrain telescopes is achieved by a sliding primary mirror. This requires a small amount of clearance which allows the mirror to move sideways a minute amount when changing focus or crossing the meridian. This minute amount is transferred and magnified by the optics to make the image shift in the field of view. 

[ronin]

Another aspect of attempting DSO imaging on an ETX-125 is they were never really designed to hang about 1Kg of camera off the back.