Jupiter 17th Feb

[The_Sarge]

First Planetary Image so please be gentle!!!!!

3000 Frames of RGB stacked in AS!2 best 50%

Wavelets in Registax

Combined in photoshop and unsharp mask applied.

Images taken with 2.5x barlow (f/25) with 30ms exposures.

The focus isn't brilliant. Focusing by eye till Bahtinov mask arrives.

Also got a fuzzy Io in the frame

Did several LRGB sets and will process the rest later. Might also try Winjupos to combine more.

Sarge

[Pete Presland]

Superb 1st image, welcome to the club!

[DrRobin]

Great first image Sarge! It does get better with practise. Like all things focus is half the battle and I focus on a bright moon and then check the surface detail. I sometimes use a mask (bright moon), but it is more of a check on precise focus. A Crayford focuser is also useful to avoid image shift when getting it precise and there is a fair amount of backlash in the main focus knob. I find focusing with the main knob (electric) has Jupiter going out of the frame.

Seeing went downhill at my house after 11pm last night, not sure what it was like at your place, but I got my best images between 10 and 11pm.

Robin

[SnakeyJ]

Nice image scale and very good first attempt - beating my own by a considerable margin! Manual focus is very fiddly at long focal lengths and I would recommend a stepper focuser. I followed DaveT's thread for an ascom compatible focuser, which all in came to less than £30! Even so precise focus is difficult to achieve given normal uk seeing. It also shifts a bit depending on angle and mechanical stability as you track an object over a period of time. I find the mk1 eyeball a better judge than a mask, concentrateing on moons and surface detail. Turning the gain up and gamma down also helps to improve contrast - though don't forget to reset these for capture.

Great start - well done!

[The_Sarge]

Robin,

I have a feathertouch Crayford focuser with the USB Focus stepper motor kit for it. Had clearish skies early evening but by the time I got a good polar alignment (well good by my standards) it clouded over.

Didn't clear over mine till gone midnight so the images where taken between 12am and 2am. packed up the scope then sat at the PC till 6am trying to get some results.

Perhaps it was the poor seeing but struggled to get any sort of sharper focus. It was very clear and seemed great transparency but the seeing I think was quite poor.

When it came to trying to apply wavelets in Registax there was  very little change to the image.

Most of the improvement came from the unsharp mask in photoshop.

Now that I am up and about I will try some of the other runs to see if anything better pops out.

Sarge.

[The_Sarge]

This is the same data set with the luminance file added as a new layer in photoshop.

[DrRobin]

Hi Sarge,

It could be collimation?  These C11 Edges (or CPC 11 Edge) seem to be very difficult to collimate, something I have spent a lot of time and effort trying to find an easy and accurate way of doing on mine. 

Up to a week ago the views through my C11 Edge weren't brilliant, yet I knew it was fairly close.  I had long wondered if you could nail collimation by slight adjustment whilst viewing Jupiter and that is what I did.  Trouble is as soon as you adjust too far you have no idea of how to get back to close or spot on and then you need a star.

It might be worth checking the collimation.

The other thing to check is your barlow, it might just be too powerful for the seeing.  Did you try any runs without it?  If your focal length has exceeded the conditions then you start to loose detail and focus is difficult to obtain.

I was running near enough the same kit as you last night and was getting exposures of around 18 - 20ms with gain of 50 on a ASI120MM and this was for 70-75% on the histogram so your 30ms suggests a slightly longer focal length.  I was running a 2" 2x barlow with my filters between the barlow and camera.

I am not sure what time it clouded over near Newcastle, just the stability of the atmosphere went off after 11pm and I gave up around 15 minutes after.

Hope this helps.

Robin

[The_Sarge]

Robin,

the scope is new, I've had it 5 weeks. The collimation seems to be spot on.

I didn't try a run without the barlow (I was using a 2" luminos 2.5x). If I get some clear skies tonight am going to try M42 first with the Skywatcher then have another go at Jupiter. 

M42 was great visually last night early on with the C11 even managed to see a little bit of colour (well a definite greenish tinge to the grey).

My imaging train is barlow filterwheel (LRGB) then through the baader neodymium filter. I might take the baader filter out of the imaging train tonight and see if I get better results.

Will do a run without the barlow then might use the baader 2.25x barlow that came with my Hyperion Zoom lense.

Just wish I had more clear skies to experiment with.

Sarge.

[DrRobin]

Robin,

the scope is new, I've had it 5 weeks. The collimation seems to be spot on.

I didn't try a run without the barlow (I was using a 2" luminos 2.5x). If I get some clear skies tonight am going to try M42 first with the Skywatcher then have another go at Jupiter. 

Sadly new doesn't guarantee precise collimation.  I was very reluctant to adjust my C11 when I first got it and then had a go and took it miles out of alignment.  A lot of practise and finding the right method/tools helped as did one of these

http://www.firstlightoptics.com/hotech-collimation-tools/hotech-advanced-ct-laser-collimator.html

I find my C11 doesn't drift much, but it was collimated pretty well last year (Feb) and hasn't been out of my obs since (or even off the mount) and it was a fair way out, so they can drift even with only small movement or over time.

I have referred to these articles in the past.

Thierry Legault's excellent page - http://www.astrophoto.fr/collim.html

Scroll to the bottom and see how mis-alignment produces a fuzzy out of focus Jupiter.  Sadly, following his instructions from light polluted, poor seeing UK skies means that the last stage is very hit and miss or even impossible.

Another site with some usefull practical advice.

http://sweiller.free.fr/collimation.html

Robin