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I captured the LRGB data for this a few weeks ago, but had to wait for the weather to clear up so I could get some H-alpha data at my home observatory. This was the first time I've tried narrowband imaging at f/10, and it was painfully slow. Next time I will do it binned, but I experimented with that and still wasn't getting the kind of histogram I want to see.

The H-alpha is necessary to show the jets on either side of the galaxy (in red). With a "mere" 3 hours of exposure the dimmer jet on the right side is barely visible. One could probably count the photons manually!

All together this is about 8 hours of exposure; 5 for LRGB and 3 for H-alpha.

8" EdgeHD at f/10 (probably really f/10.5)
QSI683wsg
AP Mach1

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Comment by Greg Marshall on May 30, 2015 at 12:38pm

I haven't used it a lot and I don't think I've ever had good enough seeing to really match this scope with my QSI camera (5.4 micron pixels). One thing I've noticed with this scope is that if there is any wind at all I have to take off the dew shield to avoid having the wind push the scope around. By itself, the scope is pretty light and small, so any decent mount would do for visual. For photography, the high magnification puts high demand on the tracking/guiding. For a mount with typical "mid range" performance (in terms of peak-to-peak PE, for example), I think it would be challenging. However, my experiment with the SX AO unit suggests that it can help a lot in this situation. At $1500 it is not cheap, but much cheaper than the AP Mach1!

Comment by Neil Heacock on May 30, 2015 at 7:59am

Interesting. I've wanted to get into roughly the 2000mm focal length, but I don't think I have the mount to sustain that kind of focal length. My Sirius outperforms my Atlas, but at 14 lbs, maybe it would handle the weight as long as it can track good enough for the focal length. I'll continue through your gallery here and see what else you've shot with it.

-Neil

Comment by Greg Marshall on May 29, 2015 at 1:10pm

Thanks, Neil. I think the EdgeHD scopes have great optics in comparison to other SCTs. I made a focus motor for it and that helps a lot with getting critical focus, but I've found that temperature compensation does not work very well with this scope. That's probably true of all SCTs because the effect of temperature is much more complicated than in a refractor or newtonian. There is also (still) a lot of backlash in the focuser. Unfortunately, if you want to use the focal reducer it's not possible to add an "outboard" focuser because the reducer has to be at just the right distance (and there is no space for anything between the scope and reducer).

Of course, there are few times around here where we can use this much magnification - the seeing just doesn't allow it. This photo was done under seeing somewhat less than the average for around here, but it is almost never good enough for typical cameras.

Comment by Neil Heacock on May 29, 2015 at 12:11pm

Greg, this shot is really nice. I love it! How are you liking that 8" Edge HD? I've thought about getting one for my next scope.

-Neil

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