Super Noob tracking question

hey yall...


some time lurker, first or second time poster.

I've got a really dumb and probably really obvious-answer question...

I understand the need for an equatorial tracker to get long exposures.
My question is this:
Why can't a guy just buy a telescope with a built in equatorial motorized tracker, take the scope off, and mount the camera on?
I mean, my little T3i and lenses aren't huge, nor heavy. Given the right 'scope/mount made for such a weight, what's the hold up to doing a little DIY fabbing with a quick release plate?

Or what about a mount like this?
http://www.amazon.com …l-Telescope/dp/B0000XMX8​O

It looks like someone already modded it with a motor. It seems like between a telescope mount fab or a set up like above, a guy could get into tracking for sub-$200 and do well.

What am I missing here? What's the obvious part I overlooked?

(I would build a barn-door but my skills at such things are ...lacking...)

My guess would be vibration, could lead to the stars looking like squiggly lines.

No reason at all. It works very well. See this thread for lots of examples.

Or what about a mount like this?
http://www.amazon.com …l-Telescope/dp/B0000XMX8​O

It can be done with that mount but just remember that it's at the bottom of the food chain and don't expect too much from it. It's great for wide angle shots and there are plenty of suitable targets.

Steve.

hey guys thanks for the response!

Tiberius, that makes sense
That being said, are there any good entry-to-mid-level telescopes that have a good reputation for piggy backing?

Hey Steve thanks for the link! Gorgeous shots over there...
Thanks also for the tip on the mount.
Might I ask what a better mount offers in terms of the final image?
Are the cheap mounts more inaccurate in their tracking? I understand that "going up the food chain"
yields better results, but what are those results exactly?

thanks again!

mac

Also I will point out that the guy who did 8 minute exposures on that mount installed the CG4 motor drives $130 and he used a guide scope probably a SSAG, which starts at $239 and with guide scope package runs $329. Also I guess the CG4 has a st4 input otherwise he modified it to accept a guide camera. With that said you can use this mount to expose with a camera but without the powerful CG4 motors or the autoguider camera you will not be getting verygood exposures at all. I suppose you could track by hand by turning the worm gear but I dont see how you could do this without introducing vibrations. For $400 you could get a vixen polarie or the ioptron sky tracker and get long exposures, not as long as an autoguided shot, but you would be way more portable than an eq mount.

Also the AT72ED is always a good starter scope at an affordable getting started price.

rogue.guineapig wrote in post #15551061
hey guys thanks for the response!

Tiberius, that makes sense
That being said, are there any good entry-to-mid-level telescopes that have a good reputation for piggy backing?

Hey Steve thanks for the link! Gorgeous shots over there...
Thanks also for the tip on the mount.
Might I ask what a better mount offers in terms of the final image?
Are the cheap mounts more inaccurate in their tracking? I understand that "going up the food chain"
yields better results, but what are those results exactly?

thanks again!

mac

Although there is a few guys that do unguided exposure, most guys don't. I have what is consider is decent mount (HEQ5 Pro) and the furthest I have done with my scope was 2 min unguided. Keep in mind I was imaging at 975mm. That was with a perfect polar alignment. The longer the focal length, the more precise the tracking as to be.

The typical setup is a mount + guiding scope + autoguider. that's what will get you in the 2min + exposure.

This is all good advice. It comes down to matching your expectations with how much effort or dollars you are willing to invest. Some people are happy with photographs captured from a webcam while others wouldn't consider anything less than a 5d3 and L glass.

As you go up the food chain you get better engineering and higher quality manufacturing. The RA bearing of the low end mount you are looking at, is a bolt going through a washer. A better mount would have ball bearings. Also the machining and adjustment of the worm gear improves. That means that the tracking errors are reduced and that autoguiding corrections are well behaved.
Very much like driving an old car with worn out steering and an unbalanced wheel versus something just off the showroom floor.

I have a CG5 and a cheap zhummell 114 eclipse setup which uses the exact same mount as the one you are suggesting. It came with a Dec motor which is of very low quality and the telescope is a 1000 mm bird jones reflector. Super pain to collimate this scope and everything is upside down without an erect image prism which is super frustrating. Aside from that if you take the time to properly polar align and drift align with the guide scope you can easily keep objects in the telescope with the Dec motor, learning your way around the EQ mount is the hardest part of the battle. That being said, you may be able to do 60 second exposures with lenses 50mm or less if you have a cheap Dec motor.