M13 revisit

[Ardsley Astro]

While I'm playing around with guiding and plate solving I thought I would stick with a target I know. I'm trying a SV165 Guide scope and using a SV205C as the guide camera (Not Ideal). I have some quite serious Guiding issue that I need to get to the bottom of. Dec backlash is still a big issue, I believe this is an issue with the gears from the motor to the worm gear, not the worm gear itself. I also have have very random large jumps in star movement, not sure what this is yet but it will endeavour to find out.

I don't know what's happening with plate solving. It just wont resolve anything. no matter how many stars it detected.

I have a SV705C on the way so I will try it two fold, as an imaging camera. and to check the Guiding I will try it as a guide Camera. 

Anyway, here is M13 again. I will call it "Guided" as there were times when it guided quite nicely.

 

[Ardsley Astro]

Figured out the plate solving,  to get focus with the DSLR I'm using a 2x Barlow. The resulting image though is not 2x, its more like 2.7x. This makes things a lot worse than I thought. I assumed with the Barlow I was at an F ration of F10, I'm actually at around F13.5. This makes Each pixel just 0.57 arc seconds. and a field of view height of only 0.5 Degrees.

What I hadn't realised is there was a setting in ASTAP to set what the field of view is, buy default its set to 1 degree. Setting this to auto, ASTAP goes through progressively smaller field of views trying to plate solve. Most of my saved images, not only from the weekend but also all previous images plate solved with a field of view at 0.53 Degrees.

Huge result in two ways, First of all I can now plate solve so the frustration of trying to find objects in the sky should be greatly reduced. Secondly I have a better understanding of what is actually happening in the Imaging train. Given I'm basically working at F13.5 I think that makes the Image quite impressive with the EQ-AL55i Pro.

I have also made some mount adjustments to the DEC. There was a shim behind the motor Mount (Red Arrows). I've removed that and adjusted the Geartrain (Green arrow) so there is very little to no "wobble" in it. Need a clear night when I am not working to see if that's resolved backlash issue and I haven't over tightened anything to the point of binding. The gear train does look a little dry as well so will order some grease in the near Future.

Big shout out to FLO though as well, I've mentioned the Backlash issue to FLO a few times and they have offered to collect the mount and have a look at it. If I haven't resolved the issue I may have to go down that line but I appreciate their patience with me as I figure out the issues and possible resolutions. 

 

 

 

[Ardsley Astro]

Well as the SV705C arrived I tried to get first light on it. Holy Moly what a difference. Plate solving just works, Every time. Instantly dropped on a star to focus. Slew to M13 (Again), plate solve and centre directly on it. It was a very cloudy night but managed a short break in them, so took as many 30 seconds subs as I could and sorted and stacked. This is just lights, no calibration frames at all. I assume the circles are dust spots. I will do some flats and Bias frames in the morning. But here is the stacked and very quickly processed pic

Edited August 4 by Ardsley Astro

[Ardsley Astro]

And here is the image with calibration frames. Considering Its with only a quarter of the exposure time I'm very impressed.

 

[Ardsley Astro]

Been playing around with GHS processing in Syril, I think this one is better

[bosun21]

One of my favourite visual targets.