# 7dmkii



## griz (Jan 9, 2006)

I went and did it the other day. Plunked down a couple of grand for a 7DMKII. After reading the review on them for astro use it was a no brainer. Haven't gotten to test it out yet. I was in Houston the past week and the weather was nasty the whole time. Looks like I might be able to test it out on the astro rig tonight and tomorrow night. Its been almost 3 weeks since the telescope computer came in and its been cloudy since. Ran into a glitch on my encoder. Having to go away from the trim tape on the EM-2 sensor. Its just too sensitive to being moved around. The cable would tilt the sensor affixed with trim tape enough so the wheel would get too close to the sensor and error out. Having my nephew drill some holes so I can mount it properly with a couple of bolts. I ordered the other axis the other day. Going to set up an autoguider so I can do some narrow band work. They require much longer integrations and a mount needs correcting when you are going for 20+ minutes. The stars will get too big otherwise. So I'm adding the other axis a dual saddle plate 60mm refractor and a self contained guider from Italy. I'm trying to eliminate the notebook from the set-up so I wanted a guider that didn't require it to function. Managed to brick the first router I tried to modify. A dumb mistake on my part. They aren't that expensive so its not a big loss just time waiting for another one to show up. Looked in several stores in H-Town when I was there last week but nobody had them in stock. The review of the MKII for astro use had a couple of stunning pics taken with the 7D. No darks flats or bias frames the noise just isn't there. Better red response as well. So no need to peel the ir filter off either. Although I might end up getting the 7D modded if I don't sell it. Don't really need two bodies. I'd rather have another lens a wide angle fast one.

Griz


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## griz (Jan 9, 2006)

*First astro shot from the MkII*










Lots more detail in the clouds. Wish I could really process these I'm sure this one would look a lot better. I've gotten lots of subs the past couple of days and I'm at it again tonight so I have lots of images to practice with now. Ordered the other axis today. I want to set up an autoguider so I can do exposures long enough for narrow band imaging. The colors are so nice when you add in that data. But it takes very long exposures an hour or more and autoguiding is a must at those lengths. Looks like its going to be a killer combination though. When the operator learns his stuff anyways 

Griz


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## griz (Jan 9, 2006)

*Another one*

This one came out pretty nice. Much more of the blue nebula than with the 7D.










Griz


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## griz (Jan 9, 2006)

*Getting close*

This one is 60 frames. Needs about 30-40 more to get the grain out of the wispy gas clouds surrounding this area but the rest is looking better all the time. Moon was up again so the colors are washed out. But at this stage of the game I don't worry about that.










I bought the other axis for my mount. Going to set up a 60mm refractor with an autoguider camera on a dual saddle plate. You need motors on both axis to autoguide. I want to do some narrow band imaging and need to be able to get good guiding for an hour or more. Without guiding that is impossible on even the most expensive mounts. I don't know if I'll use it all the time. Extra weight and complexity but we'll see its another 8lbs for the axis and probably 5 or more for the AG setup.

Griz


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## MichaelW (Jun 16, 2010)

Pretty cool shots. Looks like its keeping you busy.


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## Shaky (May 21, 2004)

Im completely lost with all your terminology, but blown away by your images! Looks fantastic!


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## Pocketfisherman (May 30, 2005)

While I don't hardly understand your first post above, the results speak for themselves. You obviously understand what you are doing and the results are spectacular!


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## griz (Jan 9, 2006)

Narrowband is using specific filters to bring out the colors of trace elements in the gas clouds. There are a couple of hydrogen (red) filters a variation of Oxygen (blue) and an isotope of sulfer that is usually a yellow color. The filters cut out most of the rest of the wavelengths and the signal you get is very low so it requires very long exposures. Autoguiding is using a small scope (finder scope) 50 to 80 mm and a small camera to determine any errors in tracking and correct for them. The autoguider software will test the mount before you start and determine how far it moves with a single pulse on the motors and then uses that to figure out how many pulses to send to correct the error. Picture a spaceship going through space and those little corrector rockets firing to keep it on course. You also use it to map any defects on the worm gear. This is kept in memory and played back as the worm turns further reducing any errors in pointing. When you have uncorrected errors the stars get big and detail goes away. And its a blur that isn't easy or even impossible to correct because of the way it happens. Things are starting to come together on the processing side. PixInsight is probably as complicated as Ps but its limited to astro stuff for the most part. You could use some of the processes on regular pictures but Ps is much better for that type of photography. When these come out of the camera there isn't much to them. A few bright stars but thats it. Its all hidden and you have to tease it out but kill the noise at the same time. Since most of what you want to keep is buried in the noise it becomes a hard task to separate them. Another big benefit of having a guider is you can drizzle the stack. Drizzling means you move it a couple of pixels in a random direction before you take the next shot. That isolates the noise and makes it easier to get rid of. For instance if you have a hot pixel it will move and not build up and look like a star. The noise processes will see it as a hot pixel since its dim and moves. To me its like a hunt. You see the prize off in the distance but you have to be crafty to make it yours. Its just like any other kind of photography. You start out get subpar results figure out why and go again. Its so much easier with a single shot color camera. Once you get it all set up and working the actual taking of pictures is kinda boring. I have it on one of my monitors and watch netflix on the other while its taking shots. Once enough get taken I start playing around with them in Pi. With the AG set up there will be more to do. But still not a lot unless things start going haywire. It was too cold and dark yesterday to get any r/c shots  Still don't know how the MkII does on the action stuff but I suspect its going to be awesome.

Griz


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