View Full Version : Meade ETX 90 & Astrophotograhy
2007-May-31, 09:04 PM
Is the above any good for astrophotography?
I've had about 5 clear nights since I got it, and a t-mount for my wife's canon 350D.
I had some difficulty getting my shots in focus so I bought some software that would allow me to control the camera from my laptop.
This helped a lot, but GAH! then the lens had misted up! :-)
My main issue is with the tracking, which to be honest, I haven't managed to get properly aligned (it is always a couple of degrees out).
Once I got it tracking saturn, (by using goto, and then zooming around a bit with the arrow keys), I found that the tracking was discreet instead of being continuous, and that each tiny movement of the motor (every second or so) caused small vibrations in the scope.
This was all really visible in the shots that I took of saturn: several small wobbly balls! :-D
So, would I be better off using a webcam and registax ?
Any tips would be really appreciated.
paul f. campbell
2007-May-31, 09:46 PM
I have a etx 125 and its taken me a long time to master the scope. There are programs out there that will help you alot.
First off if you dont use polar mode you should learn to, your scope will track much better. If you dont have Polar finder get it. This program shows you how to place your scope to true north. best pair shows you which stars to use when doing your alignment. both are freeware programs.
I use both of these programs, and with a little practice you will be able to keep an object in your lens for a long time. I think that your canon 350d is a little to heavy for the scope. For the Moon and Planets I use a sac 7 ccd camera and do avi's only. I process them in registax 4, photoshop cs2, photofilter, noiseware and helicon. All of those programs are free except photoshop. One last thing. Buy a auto focuser for your scope jmi makes a very good one for the meades. This is a must have item when doing
astro photo work. If I can help you feel free to e-mail me later Paul
2007-May-31, 10:38 PM
thanks Paul, that's gold! :-)
So it sounds like the scope/camera combination that I have is not really suitable for the long exposures that I was doing. Is that right?
In the short exposures that you get doing avis, the jerky tracking provided by the mount won't really show up ?
I'd never heard of the polar mode before, I'll give that a whirl
Thanks a lot!
paul f. campbell
2007-May-31, 11:41 PM
Do you have the tripod that tilts I think its an 884 not sure, any way you need a mount that will tilt so you can use your scope in polar mode. Go to Mike Weasners mighty etx site. You will find every thing you need to know there. go over everything you can find from a man named DR. Clay Sherrod. he will take you where you want to be, belive me he is that good.
DR. Sherrod is the guy that does the Supercharge on meade scope. He has worked on my scope twice pluse we stay in touch from time to time, he is a great guy. If I can help again please type later Paul
2007-Jun-01, 01:25 AM
I use a 9 year old ETX 90 which I polar align. Years ago I bought the T-adapter and extension tubes to attach a Pentax ME Super 35mm to it, but I was never happy with the set-up. The mirror slap caused too much vibration, and there were other issues. But recently I discovered that my Canon A640 (http://www.dpreview.com/reviews/canonA640/) could be attached to the scope by using some ABS plumbing and eyepiece projection. I control it from my laptop using the Canon remote software. It's been quite a learning curve, and I haven't had much opportunity in the last couple of weeks, but I have had some success with lunar imaging. I generally take images as fast as it will allow me to, rather than AVI's, and I stack them using Registax 4.0. I have a lite version of Photoshop that came with one of my other digital camers, but I've been playing with Corel Paintshop Pro 9 which I got as a free download. So yes, it is possible to use the ETX 90. Examples here (http://www.bautforum.com/showthread.php?t=57961), here (http://www.bautforum.com/showthread.php?t=56420) and here (http://www.bautforum.com/showthread.php?t=56353). (Some others are around too.)
My version of this scope has a simple clock drive that runs continuously, but it has really poor bearings and cheap plastic gears, so the tracking isn't great, but it does not have the problems you've described with yours. I suspect you had it set up in alt-az mode and allow the autostar (or whatever its called) to do the tracking for you. If you can polar align your scope and configure it to operate that way, I'm sure you'll have much better success.
Paul mentioned that your camera might be a little heavy for that scope. My combination is probably too heavy as well, but it manages.
Also, as Paul mentioned, Weasner's Mighty ETX Site (http://www.weasner.com/etx/menu.html) has a wealth of information that you could spend weeks reading.
I'll never get the results some of the guys here get, but it has nevertheless been a rewarding process for the short time I've been trying digital astrophotography. My biggest problem right now is that at my latitude it simply doesn't get dark until very late, and the sun rises again very early. So I look at other peoples results and wish I were so fortunate!
2007-Jun-01, 08:29 AM
to see job geheniau's fine work with an ETX90 on deep space objects
I do think your canon is far too heavy for an ETX-except if you want to use it for widefield shots piggybacked on the ETX
2007-Jun-01, 08:20 PM
Thanks for posting that link, seeker. Added to Favourites - a new source of inspiration!
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