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Galaxy of the Sculptor

MarsG76

By MarsG76
in Imaging - Deep Sky

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MarsG76

MarsG76

Posted
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Hello Astronomers,

During the week when I was imaging the Helix Nebula, I was exposing it when it was east of the meridian.

So as it hit 15 degrees past the meridian and the meridian flip happened, there was no guide star in the OAG FOV so I had the option to pack up and continue imaging another day or try for another object and hope for a guide star.

As the sculptor galaxy was close to the location I slewed to it (with favour western horizon selected in the CGEM settings) and to my joy when the sculptor galaxy was framed a 1/3rd of the frame to the edge there was a guide star in the OAG... WOO HOO :grin: ... and so a second object imaging continued.

After getting 3 nights worth of ISO400 10 minute RGB subs, I found that after processing the image was very amber at best.. almost sepia... and no matter what I done to it it always looked too green or purple at certain parts... just didn't look right.

When I eventually got a chance, I was going to image some pure blue subs to add to the image to correct for the amber look, but as luck would happen, forecast was for at least a week of clouds and rain... this week was no better BUT I did see a break in clouds the other day with a 3/4 FULL MOON!!!!  :mad:

I couldn't afford to let this opportunity go to waste so I imaged NGC253 through a Halpha filter to cut out the moon glow... remembering that when imaging through Halpha in the 40D there is a lot of data in red (of course) and about 30% as bright in the blue channel.... I thought that I could use that added to blue as well as add some halpha to red and perhaps reveal some nebulosity.

I only managed 8 x 15 minute subs before clouds started coming and 4 out of those were usable... here is the result.

Thanks for reading my babble....

MG

post-43662-0-36325000-1440807260_thumb.j

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adamphillips

adamphillips

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I have one of those tubes, but I gave up on imaging with it, without ever trying. I have the f6.3 reducer and the whole setup to image with it, but I thought the stars around the edge were going to be really bad. I did a little bit of imaging with it with my old canon.

your field looks pretty flat. maybe I could do some imaging with it after all with my ccd. at 1280mm

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MarsG76

MarsG76

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I have one of those tubes, but I gave up on imaging with it, without ever trying. I have the f6.3 reducer and the whole setup to image with it, but I thought the stars around the edge were going to be really bad. I did a little bit of imaging with it with my old canon.

your field looks pretty flat. maybe I could do some imaging with it after all with my ccd. at 1280mm

My work around any coma at the edges is to simply work with a crop limit of 3000-3200 x 2000-2200 from the 40D 3888x2592. That allows me to crop out any bad stars due to coma and vignetting.

Overall I'm very happy of the quality of subs that I'm getting with my NS8. I can't stress enough that tracking and focus are the most important to quality.

A f6.3 reducer & flattener really does do a good job at fixing field curvature delivering a very flat field, at least for a APS-C size sensor.

Don't give up.... Your OTA is capable of some great close up images of DSOs, especially useful for the smaller objects such as the dumbbell or butterfly nebulae.

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