M45 - Unguided tuned Star Adventurer

[Guest]

Details
Object name	The Pleaides
Object ID	M45
Date(s)	28 January, 2019
Telescope	Altair 60mm EDF
Camera	ASI1600MM
Luminance	30x1 min
Red	30x1 min
Green	30x1 min
Blue	30x1 min
Ha	0
Oiii	0
Sii	0
Total time	1 hour – per channel
Frames	0
Processing	PixInsight / fully calibrated lights / Levels / Curves / SCNR
Notes	An exceptional event is occurring! We are having an unusual spell of clear cold weather - and tonight looks promising so Welford Observatory is ready - although remotely as the main scope is down for maintenance at Dark Frame Optics. Having received my Star Adventurer mount back from them recently I've been having a blast trying it out with my Altair 60 EDF. Skies are looking good during my lunch break ZWO ASI120MC All Sky camera ....and then as usual ....the sky didn't "get the memo" this evening   ZWO ASI120MC All Sky Camera ...but I'm all set up ready to go ... ZWO ASI120MC All Sky Camera, Altair 60 EDF and Star Adventurer mount The clouds have parted and I've got things ticking over on M45 @ 60 seconds with no star trails - very happy with that (2000hrs) ZWO ASI120MC All Sky Camera ....and while we're looking at all sky shots ....cause let's face it once your rig is set it's a machine that tracks the celestial clockwork of the sky without your assistance ....I compiled an .avi of the entire evening. Funny watching all the trails shooting across the sky, some of them are aircraft, I think one or two are shooting stars...one that I noticed in the West did a sort of loop over two frames - that's what's going on up there when we're not looking lol! Keep an eye on the telescope as it tracks M45 across the night sky. So that gives an astro-photographer something to do while the main meal is cooking. The final tally of frames was 30 on each channel (luminance, red, green and blue). This isn't a lot for any object but as this is just a test I'm comfortable it will be enough to produce "something" worth looking at. I processed the frames in PixInsight using the following processes Batch Preprocessing with 30 flat field frames and 10 dark frames on each sub frame. DynamicBackgroundExtraction Background Nuetralisation Colour Calibration Histrogram Transformation PixInsight users will notice I haven't unleashed the full arsenal of tools on this object as it's really only a test. Channels combined - red, green and blue - and processed   ...and the Luminance channel is processed prior to combination with the r,g and b channels.     Processed Channel - Luminance And now these two channels are combined to create an LRGB image. First though - a couple of masks for bringing out detail and contrast are required. A range mask is prepared to protect the object from degradation when noise reduction and colour management is carried out on the background. PixInsight - Range Selection Mask   PixInsight makes the creation of these masks extremely easy and intuitive. A star mask is created to isolate them for reduction via MorphologicalTransformation and to protect them during other adjustments. PixInsight Star Mask Here is the final process and the ultimate test of whether I will be using the Star Adventurer Mount in its unguided mode....   So - what't the decision? I'm confident I got the polar alignment as good as I'm likely to using the QHY PoleMaster. This means any issues are insurmountable and need to be assessed for their ultimate impact on the decision. M45 The Pleiades - Welford Observatory ...and here's it's orientation (close) in the sky on the night M45 - The Pleiades First - star trails? Looking at the image above I don't see any issues and frankly I'm not one to zoom in and see if stars are slightly egg shaped due to poor guiding. However, for results that provide clear and crisp detail these imperfections need to be addressed. Looking closely - loath as I am to do so - shows considerable drift in the tracking - causing considerable elongation of the stars Star trails - acceptable? Frankly - I think, for a portable set up that doesn't rely on guiding - I think this sort of error is acceptable. However, in my next test, I think I'll demonstrate that not only can you guide with the Star Adventurer, there is really no obvious reason why you shouldn't..... WOBSASTRO January 2019

[SteveNickolls]

Thanks for posting. With the telescope at 360 mm FL you are pushing the SA at its limits so a good attempt without guiding. If you used Start Tools for processing it has the ability to turn eggy stars into round stars if you needed that.

Cheers,
Steve

[Guest]

40 minutes ago, SteveNickolls said:

Thanks for posting. With the telescope at 360 mm FL you are pushing the SA at its limits so a good attempt without guiding. If you used Start Tools for processing it has the ability to turn eggy stars into round stars if you needed that.

Cheers,
Steve

I'm just getting set up to try guiding it tonight ?  

See if we can scramble them eggs LOL! 

Actually, that wouldn't be very attractive in a star field would it....

David