Many failures on this object … CTB1
That’s a collection of successive failures … It’s okay, as far as I can understand what I did wrongly. I got two objects in mind for this night, and I missed both.
Since last year, and more specifically since Sardegna, I got only one night with clear sky. I posted the Iris Nebula that I caught on the 11th of January, and since this day, I got nothing … so I thought I could try on the 19th of March to shoot in a bad-forecasted-average sky … From the Iris Nebula tests (because it was about testing the Takahashi Mewlon and some new equipments), I got a lot to think about guiding. I got some good feedback and information from the astronomy club, and I felt the guiding issue could be solved easily.
I’m back with the Celestron C9 with the Hyperstar. Mostly because I like so much this setup, and because it is a fast one. No filter wheel with the Hyperstar, as the camera is in front of the Schmidt lens. So I dismounted my SHO filters from the filter wheel and I’m using the manual filter drawer.
The object named CTB1 is something I have in mind for a long time. Very faint, very difficult to catch, very beautiful. Let’s start by a bit of history : it has been discovered by Mr George Abell (the guy has his own catalog) and was catalogued as a planetary nebula in 1955. Couple of years after, he felt it could be a Supernova remnant instead and it was confirmed in 1968.
This object is big ! And astrophotographers are spending tens of hours to catch it. It has a lot of Ha and a bit of O3 gases so I thought that using the filter HaOIII only would be sufficient.
I prepared my setup, grass was incredibly wet so I felt I needed my anti-dew shield to protect the Schmidt lens … but I couldn't find the adaptor for 2.5mm power for the heater… so I thought that maybe it would work with only the shield without heating the lens : first big mistake.
I aligned my mount to the Celestial pole and I discovered for the first time that I need my mount to be tightened on axes to avoid some moves and bad maths from the Polar align software … you know, these steps should be automatic now, after two years and a half of experience … nope, I am still surprising myself by doing these things wrong … anyway, I got a polar alignment done quite quickly and quite perfect so that’s okay.
Then, I wanted my guiding system to work … and I got the same noisy picture than the last times I tried … but the information and help I got from my astronomy club were correct : I needed to position my camera with the correct distance from the guide scope … DONE and it’s working now. I’m good about that, finally !!!!
Then, I want to get a good focus on my primary optical chain. NINA software can handle this and will tell my electronic focuser to do it … but it struggled a lot … I checked my Schmidt lens : nope, no dew in there …why the autofocus doesn’t work ?????????? I’m fixing the guiding system and now I face a focus issue I never got …
I finally get an average focus (after 20 minutes ...) and here’s the biggest challenge for this CTB1 object : it is part of a new catalog (CTBxx) and this catalog is not part of my shooting software. So I must put the Right Ascension and Declination coordinates manually … and I don’t want to dig into changes of these coordinates per year … but it is a bit of “good luck with that”. And on top, the object is so faint, so dim, that in order to get a glimpse of it you need tens of minutes exposure to maybe see it. So centering the object was the biggest challenge. But I felt confident that my polar alignment was very good so the manual coordinates would be ok to get the object centered. Shooting blindly … that was my strategy … and it was a mistake …
I must also admit that I was trying multitasking (with other not astronomy related tasks) during this night … that was probably the biggest mistake of all …
And that’s it, I let the setup shooting for as long as the guiding system will not loose the reference stars. After two hours and fifteen minutes, I can see that the latest shot is catching the top of the trees from the hill. Time to stop shooting and to figure what I got from this session.
The result was awful … I mean, not only the object doesn’t appear after stacking the 71 shots of 120s exposure each … but in addition the stars seem weird … so … what happened ??
Multitasking during a shooting : not ideal, don’t do that, ever
There is a reason for using anti-dew shield and heater … don’t assume it is not needed
When you get a huge white spot on your pictures in the middle, guess what ? It would be also smart to use the anti-dew heater of your camera … WHY didn’t I turn it on ??? I don’t know but I forgot that too…
I checked afterwards about the coordinates I’ve put in. They were not that bad, but I was definitively not on the object. I was between laughing out loud and crying from shame … It would have been smart to get a 5 or 10 minutes snapshot to check if the object was there before shooting.
I wasn’t in focus … AT ALL !!! I guess the sky was really bad as I checked all pictures and they are out of focus, all of them. I thought about my guiding system going wrong, but I was checking during the shooting : that was the only thing going very well ! Karma on the 19th of March …
Because of the obvious vignetting and the white spot and the background noise, I took some flats to calibrate my poor lights pictures the morning after the shooting … the sky was cloudy and my flats are awful too …
Exifs : Celestron C9 + Hyperstar / PegasusAstro Nyx-101 / PlayerOne Poseidon C Pro cooled at -10°C / Askar D1 HaOIII filter / Guiding System Askar 135mm scope with PlayerOne Ceres C
71 lights 120 seconds each - 54 selected for stacking (1 hour 34 min exposure for final shot)
50 flats - with clouds …
Stacked with Pixinsight (WBPP)- Post-Treatment with Pixinsight with a lot of try-outs to get something, without success.
P.S. In case you see some reddish nebula in the picture … it is SH2-168 … not that far from NGC7790 and NGC 7788
P.P.S. I don’t give up on this object. I must catch it this year.
P.P.P.S. I mentioned two objects as targets. I didn’t talk about the second one … but it is my next target, for sure.
