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Comixx
2003-Jul-01, 02:08 AM
Well, finally got a piggyback setup working with my brother's Meade SCT. Went out Saturday night to our exclusive west-Phoenix site to test it out. It's so much better for casual pictures than messing with adapter tubes and trying to figure out prime focus on dim objects. You just point the scope, open the shutter...and remember not to adjust the scope while the shutter is open ;)

Anyways, here is my pic of the Lagoon Nebula / M8 (http://www.xericstudios.com/photos/skies/lagoon-nebula.jpg). I'm so excited by this success...not only the picture itself, but the fact that I found a Wal-Mart Photocenter employee who understands the phrase "The background in these pictures should be black, and print every frame". I took several pictures, some open clusters, some over-exposed of Mars, etc, just to see what field-of-view I could get. (And, now that RichField mentions it, I did get the Triffid / M20 up and to the right of the Lagoon, too! I'm better than I thought :P)

Camera specs: Canon Elan 7E, 80-200mm Canon lens (zoomed to 200mm), Kodak 800 MAX film, f/5.4, exposure time approx. 8 minutes.

Humphrey
2003-Jul-01, 02:24 AM
Real cool comixx. :-) Now how do i simulate jealousy over the net?

DStahl
2003-Jul-01, 05:42 AM
Yeah, that IS cool. I was not expecting the bright colors.

Glom
2003-Jul-01, 11:07 AM
Who says 35mm photography's dead?

I'm seriously impressed and jealous.

What's causing the trails towards the edge of the field? It makes Lagoon look like NCP.

Do you mind if I save it so I can use it as a desktop wallpaper?

Comixx
2003-Jul-01, 12:14 PM
Thanks for the compliments :) You're welcome to take anything I post for personal use...just dont pass it around without asking me please.

Anyways, the reason it streaks around the edges is because, as the SCT auto-tracks whatever we have it locked onto, it also rotates slightly, causing anything in a picture to rotate too...it sorta simulates whatever we're looking at as Polaris...anyways, you can buy a De-Rotator device that keeps the camera at a certain degree relative to the tracking ($400 dollars we dont have) - or you can get a Wedge device, which mounts under the SCT itself, putting the scope at a predetermined angle, which also counteracts the rotation (which is less expensive, but adds to setup/takedown time at the site).

To limit the streaks, I have to limit my exposures to around 5 minutes, anything more starts the streaking, as you see in that 8 minute exposure.

kucharek
2003-Jul-01, 12:22 PM
I have to limit my exposures to around 5 minutes, anything more starts the streaking, as you see in that 8 minute exposure.
I always though, it's enough to expose for a few seconds when streaking ;-)

BTW, that image rotation: Isn't it because you may have only an azimutal mount? Then, when tracking, the object seems to rotate relative to the tube. I can't imagine why a rotation is induced with an equatorial mount.

Comixx
2003-Jul-01, 12:53 PM
You are correct kucharek, the Meade LX200 GPS 8" (well, any of the Meade SCTs) are altazimuth mounts. The field rotation happens with any altazimuth mount that isnt polar-aligned. The field de-rotator is a mechanical device that fits on the end of the SCT and rotates the camera in the opposite direction, canceling out the rotation effect. The wedge tilts the entire altazimuth base and the scope to get it into polar alignment (which means you have to have the base facing exactly at Polaris, and mount the 65 pound scope onto it at the 25 degree or whatever angle...a bit more complicated than the field de-rotator).

RichField
2003-Jul-01, 06:55 PM
Great picture!

Though I do believe you've made a mistake:
I think the title should read "My first (and second) nebula picture!".
If you look to the upper right of that picture, I believe you have managed to capture M20 (The Trifid Nebula) as well. The star fields appear to match up correctly from my source.

Again, nice work.