I have been experimenting with optimizing unguided performance with my G11 and wanted to share an example of what's possible right now.?
Most importantly, this is unguided and at a pretty good focal length. My G11 was purchased around 2010 and has been steadily updated through the years. I think it's pretty much what you'd get if you bought it today, except it's pretty banged up lol
the target is webo 1, a tiny planetary nebula on the fringe of the heart nebula.?
this is a single 300 second frame (Ha filter)
scope is ES165?@844mm focal length, i think it's at f5.6? i have to check the reducer specs
camera is SX trius pro 694, no cooling (camera issues with cooler)
unguided exposure
no PEC
the important stuff on the exposure
fwhm 1.914
eccentricity 0.5140 (roughly, star eccentricity?of 0.5 is considered round to the human eye)
I hope i used settings that represented a good test (I used the Ha filter because otherwise my luminance or other broadband filter would blow out due to bortle 9 skies)?
?
i've attached a JPG to this email, it's an unimpressive target but the star profiles show the performance (it's not cut off: i'm aiming for the edge of the nebula where webo 1 resides)
the link to the raw fits is here if you want to pixel peep
this was one of the best frames, and of course image quality varied quite a bit
Observations:
Polar alignment and tightening the alt/az knobs seem to be really critical, far more than I anticipated. I used sharpcap 3.2 for polar alignment (ended up measured at 14") and replaced the stock bolts with #8 hardened hex head bolts (nuts for the az), and tightened them carefully using a crescent wrench.?
I also took care to balance the mount in both ra and dec (using spring loaded worms, so no weight bias) and another important thing was not to overtighten the clutches: only as much as needed to stop the axis moving
I don't think this says I can image unguided all the time just yet. there are still a fair number of frames that show some star elongation, enough that i can see it at 200% magnification. I'm not sure if it's polar alignment or other, so i'm still experimenting
