It’s a challenge to image dark nebulae in light-polluted Flanders. So let’s try it!
This is the “little eagle” nebula, which I captured a few years ago as a tiny spot on a wide-field Plejades @180mm. Now the framing only features the Eagle head ; imaging with the Esprit and the ASI183mm.
It’s a bit dark – but what did you expect from a Dark Nebula? This is 10x300seconds on R, G and B channels and then 29x300s on Luminance. No Light Pollution filter used.
This is the overview, with on the right the Pleiades, and on the center left the Eagle Head (upside down).
I’m not sure what to think of this image. There’s a fair amount of detail, also the outer regions are visible. It’s fake colors anyway so I tried to balance colers for an esthetic appearance combined with a maximum of detail. The thing is, when you look at the individual B/W images, they seem far better in terms of quality, smoothness, noise and detail. It’s when combing them into color that they suddenly require maximal processing to get something out of it.
Skies were not very good, lot’s of high altitude clouds and contrails. The data has been gathered over maybe 6 or 7 nights for the past weeks.
I have RED and GREEN filtered data still that I did not use in this combination. The total integration time is over 18 hours. I guess lots of rain and clouds should come over to get me reprocessing again? I’m not sure what to think of this image. There’s a fair amount of detail, also the outer regions are visible. It’s fake colors anyway so I tried to balance colers for an esthetic appearance combined with a maximum of detail. The thing is, when you look at the individual B/W images, they seem far better in terms of quality, smoothness, noise and detail. It’s when combing them into color that they suddenly require maximal processing to get something out of it.
There are good reasons to switch the a motor controlled focusser:
automating sequences in Sequence Generator Pro
Automated focussing after a filter wheel switch
Getting comfy inside while able to fully control your telescope
Go to sleep while your equipment takes care of image acquisition
no more slipping of the focusser with heavier loads
Why the PegasusAstro focuscube? I actually ordered the Lacerta motofocus first, however there were delivery problems. It first took two months to deliver, after which nothing happened. On inquiry I learned that it would take another two months. I decided to change to the PegasusAstro, and a few days later it was on my telescope, mounted and working…
Both these brands could demonstrate that the motors would actually fit on an 120mm Esprit. That was my main reason, other considerations were the strict requirements of connecting to a PC, working with SGP and similar software, and the ability of attaching a handbox. The PegasusAstro FocusCube was standard delivered with a temperature sensor (option with the Lacerta).
It was not difficult fitting the FousCube to the Esprit standard focusser. The only challenge was to shift the L-frame so that the two bolts could fit the focusser body, while a the the same time the axis and the connecting cylinder were also aligned. The two screws were part of the assembly of fixation material delivered with the FocusCube. They fit the smaller screws of the Esprit focusser.
Getting autofocus working with Sequence Generator Pro, and the FocusCube was also a matter of trial and error. After two nights the autofocus works very well.
This is the full set of settings that work with my equipment:
when you cannot get a nice ‘V’-curve when autofocus runs, try to increase the exposure time. The image statistics should give you at least 50 stars. Below that value, the HFR values become erratic and unreliable. I use 20 seconds for a 7 nm H-Alfa filter.
remember that autofocus is intended for small corrections, so you should already be near focus before you can run it
always run autofocus before a filter switch. In theory the filters are parfocal, however in practice they rarely are
I only run autofocus per degree Celsius. If the temperature doesn’t change, there is little reason for focus. The whole autofocus process takes time, maybe 5 minutes or so, time that you loose imaging.