ZWO ASI224 First Light and Io Transit

[Astro_Dad]

First opportunity to test this camera on the planets with my Celestron StarSense Explorer 10” Dob. Impressed by what is possible using simple untracked planetary AP and stacking software (as exemplified by @sorrimen et al on this forum!) 

I’m still very much an observer in the main, but I’ve enjoyed the occasional dabble as it provides some astronomy opportunities (on the processing side) on intervening cloudy nights. 

First light 16/17 Sept ambitiously aiming for some footage of the Io shadow transit. I’ve had some success with this camera in the past using my StarQuest EQ mount with RA drive (with 102 Mak) but with this recent repurchase of the camera it’s the first time I’ve attempted untracked on a (fast) manual Dob. Overall this turned out to be much more challenging than I’d expected. 

Initially tried in conjunction with a 3x BST Barlow providing effectively f/14.7 - in the target 3-5x sensor pixel size range usually recommended. I found it almost impossible to find and hold the target (Jupiter) in view- either full frame or using ROI of 800 x600. Guided by some pointers from SGL members and elsewhere, I was aiming for around 300 gain and 75% or so on the histogram (with Raw8 as the output format). 

However it became a case of trial and error in the end, abandoning the Barlow and using using the camera directly inserted with the supplied nosepiece. Basically at this point looking for the target simply drifting across the field of view with the gain etc. simply a direct function of my judgment on the brightness and level  of detail by eye. No science involved! 

First attempt c 60s of footage without IR cut filter, second attempt around 50s (at around 1.30am for the shadow transit ) with IR filter. Cut short as laptop battery died! Not the most successful of evenings to this point… that said though It is going to take a lot of practice for me to be able to get anywhere close to 3 minutes of video by manually holding the target in the FOV. Credit to those who have managed this here!

Processing in PIPP required the debayering of monochrome frames step due to my choice to capture in RAW8, but other than that the process was a reminder of previous attempts - AS!3, Registax for wavelets and a final touch up in GIMP. 

I was pleasantly surprised at the final result - a touch over processed and lacking in image scale due to no Barlow involved, but clearly captures the Io shadow transit early this morning, and even the moon itself is just visible showing a milky colour contrast to the Jovian disc. 
looking forward to doing more with this motivating start!

[sorrimen]

Motivating indeed! Glad you’ve managed to get first light and a real promising start. Can assure you that my first attempts didn’t come close to this and improvement is exponential in the first few sessions, so it’s up and up from here. Can’t wait to see what more you come out with! 

p.s. looks like you may be a touch out of focus. I know just how hard it is to tell in live view, but any cheap electronic focuser is a godsend for our sort of imaging if you don’t have one.

[Astro_Dad]

22 hours ago, sorrimen said:

any cheap electronic focuser is a godsend for our sort of imaging if you don’t have one.

Thanks, one to research potentially - or maybe a bahtinov mask? 

 

[sorrimen]

Cheap(ish) skywatcher one works well enough for me, as an example. Bahtinov only works on point sources, so could be used on jupiter’s moons but nothing works better than focusing using surface details I’ve found. Can always try Bahtinov first!

[Nigella Bryant]

Cool, I had my first light with Jupiter on the 17th September. I was blown away with the C11 and the Zwo Asi 224mc. It's an amazing camera.