Stupid Question

[Maximus]

Hi All

I'd like to have a good go at astrophotography but seem to be hampered by my choice of scope. I've got a Meade ETX 125EC Tripod Wedge and I've been advised that I really need a short tube refractor on a germany equatorial mount. I know the ETX is not a refractor but is it worth sticking the OTA from the ETX on to a mount such as a CG5 (with goto) or should I just sell up and start again!

Thanks

Ivan

[Helen]

Depends what you want to photograph really! If its moon and planets with a webcam then yu'll be fine as it is. If its deep sky then more problematic as you'll need longer exposures and the focal length of the ETX will make tracking a bit challenging. You could get a focal reducer though (a cheap but decent ATIK 0.5 reducer would be OK if your camera only has a small chip) and with the wedge try it and see what you get.

Helen

[Maximus]

Hi Helen,

At the moment all I have is my Nikon D40x which is what i'd like to use if possible. It might not be the most popular on the market compared to the canons (as far as astrophotograpy goes) but I like it and more to the point I don't have the money to spend out on another DLSR.

Ivan

[Maximus]

Oooops forgot to mention, deepsky is what i'd like to photograph.

Ivan

[FLO]

Ivan, I hope this doesn't sound defeatist but if it is deep-sky imaging that you are after then you are better off selling the ETX and starting again. Its not that you cannot achieve some success with your current setup, its just that it'll be an uphill struggle that might put you off imaging altogether.

If you do persevere with what you have then buy a piggy-back adapter then mount your DSLR with its standard lens onto the ETX and try some wide-field imaging. Be careful though as the ETX125 motors and drive don't have a great deal of reserve strength.

HTH

<edit> It wasn't a stupid question

[Maximus]

Don't supose you offer part exchange!!!! )

[Ben Ritchie]

Ivan, I hope this doesn't sound defeatist but if it is deep-sky imaging that you are after then you are better off selling the ETX and starting again.

Agree...

Its not that you cannot achieve some success with your current setup, its just that it'll be an uphill struggle that might put you off imaging altogether.

...completely!

You can image through pretty much anything, but working with a short focal length refractor on a GEM is considerably simpler than trying to image with the relatively long focal length (and 'slow' speed) of the ETX. There's enough frustration in deep-sky imaging without making it harder on yourself than it needs to be.

Looking to piggyback the DSLR is certainly a good idea. I only know Canon, but they do a very affordable 50mm f/1.8 lens that's good for widefield work and i'm sure there's a Nikon equivalent. However, i'd reiterate Steve's warning, you need to be careful to keep the ETX in balance - i.e. if you release the clutches the tube shouldn't fall forward or backwards with the camera piggybacked.

[Ben Ritchie]

One other thing, if you're thinking of going down the deep-sky imaging route, i'd really recommend buying a copy of Wodaski's "New CCD Astronomy" before spending money - he'll tell you what Steve just said, amongst many other things, but it's a very good introduction to the highs and lows of DSO imaging.

[FLO]

Don't supose you offer part exchange!!!! )

We don't sell/trade Meade ETX - sorry.

[Astrosurf]

Wonderful question - not stoopid at all! It's what I want to know too!

I hope this question helps you too as I don't want to hijack!

What did you mean Helen when you said, 'focal length of the ETX will make tracking a bit challenging'? I don't understand focal length stuff and planetary versus deep-sky photography! I have an 8" Skywatcher with an HEQ5 mount.

Do y'all want me to start a new thread??

[Keagle]

Because of the focal length being longer, any movements made by tracking 'errors' or incorrect tracking will be exaggerated.

Kurt

[Helen]

^{To explain what I meant earlier...}

^{If you have a long focal length, say f10, then you will operating at high magnification and so your tracking needs to be very accurate to keep things in exactly the same spot. At shorter focal length and lower magnification the camera will be more forgiving of tracking errors.}

^{For lunar and planetary photography with a webcam you'll be taking very short (split second) snapshots of the sky because the targets are so bright, picking the good ones and adding them together. Therefore tracking isn't a problem because the exposure is so short.}

^HTH

^Helen

[Keagle]

One thing that confuses me is when people state focal length in focal ratio. Surely if you have an f/5 200mm scope and an f/10 100mm scope they both have the same "magnification"(focal length both being 1000mm)?

Thanks!

Kurt

[Reggie]

You're going to need a guidescope if you're going to get at all serious about DSO imaging, it's really worth getting guiding sorted early, it will save countless wasted images, unless of course you can have a permanent gem setup thats been drift aligned and well pec trained.

With a short tube and a gem mount, You might want to consider using the ETX ota as a guidescope, the long FL compared to a F5.9 388mm short tube refractor will give superb guiding with a reasonable guidecam, + if you ever want to dabble with planetary you've also got the etx to do that as well, a very flexible setup that would allow you to take larger mag images of some of the smaller dso and globs as well as all the big widefield favourite nebulae and galaxies.

The D40 will take superb DSO pictures on the right scope but you'll need a shutter release cable or a remote.