Rapidly going backwards with Saturn!

[Stargazer33]

Hi, I am really disillusioned and don't know what to do next!

I started imaging Saturn in April and got this as my first attempt:

I was quite happy with this; you can see the Cassini Division and there is some banding on the planet.

I have only managed to get out four times since then to do more imaging and I have only been able to achieve this:

There is no Cassini Division and very little, if any, banding on the planet. The imaging rig is exactly the same with the exception of my new focuser which should make focusing better, so I can't understand why things are so much worse than two months ago. I know we are now past opposition but surely that can't make that much difference and other people are still getting good images with smaller aperture rigs.

I did 21 video runs of between 1500 frames and just over 3000 on Saturday night from 23:30 to 00:30, all had individual frames like this one:

What am I doing wrong?

Imaging rig: C8 with Revelation Superfocus 2" R&P dual speed focuser on an Advanced CG-5 GT mount, Philips SPC900NC, Revelation Astro 2.5x barlow, no guiding.

I started off with a Baader Neodymium filter on the webcam but took it off for the last 3 or 4 runs which did allow me to turn down the gain but it didn't improve the images at all. They just had a slightly different colour cast. I have run the camera during the day through my Travelscope 70 and have attained perfect focus so it isn't the camera.

Any help/advice would be most appreciated.

[Freddie]

It looks a touch over exposed but your big issue could just be the seeing if you are happy with your setup. I've been out a couple of nights recently and just given up after an hour or so without even bothering to image at all.

[Stargazer33]

Thanks Freddie, the next time I get out I will try reducing the brightness and contrast a bit. It's just I see people posting far better images than my first attempt with 127mm Maks and MS Lifecams.

I am beginning to wonder if living right next to the Channel is affecting the seeing. All that evaporation during the day must be putting a lot of water molecules into the air around here. As Saturn is low and to the South it may be having an effect. What is it they say about bad workmen blaming their tools?

Well there is always tomorrow, or the day after, or the day after that...

[Catweasle]

Much like Freddie I live in Kent and am having exactly the same experience.After a couple of attempts earlier on in the Saturn season ( C11 with dual speed focuser ect much like your own setup ) I have pretty well decided that it is a seeing conditions issue as well so all we can do be patient, keep trying and hope for better conditions.It's just the way it goes I'm afraid.

[JamesF]

The seeing can really kill an imaging session. I've had nights when the different in good and bad periods was very obvious in the processed images over the course of an hour or two. The best you can really do is stick with it, try to keep the focus tight and be prepared to give up and throw away the data if the sky doesn't want to play ball.

Even if the seeing is poor, practice is valuable. Just try to get the best you can out of the conditions and build up the experience.

James

[IanL]

It could well be seeing; have had similarly variable experiences over the years without changing my setup. Sometimes lovely crisp images, other times a blurry mess.

Check the altitude of Saturn at the times and dates that you took the images using a planetarium as it might be atmospheric dispersion. If you're imaging at below about 40 degrees above the horizon it will have a noticeable effect on the sharpness of the image. Different wavelengths of light refract more or less, causing the same sort of effect as chromatic aberration but only in the up/down direction relative to the horizon, and below about 40 degrees you will have much worse results.

There are prism devices that you can purchase that allow you to correct for this problem, but they're not cheap. Another option is to use colour filters with relatively narrow bandwidths to shoot separate AVIs, stack them and then RGB combine the final images. (Should be ok on Saturn but might not be feasible for Jupiter due to the speed of rotation).

[ronin]

This may be stupid, but the title is going backwards.....

When does Saturn start to appear as if it is going backwards in the sky?

I would have thought that it occurs around the time of opposition.

Just wondering if the mount is moving in one direction while Saturn is (apparently) moving in the other on it's retrograde bit. This would throw any imaging out.

Found this: Saturn retrograde lasts from 18 February 2013 to 8 July 2013.

[dephelis]

This may be stupid, but the title is going backwards.....

When does Saturn start to appear as if it is going backwards in the sky?

I would have thought that it occurs around the time of opposition.

Just wondering if the mount is moving in one direction while Saturn is (apparently) moving in the other on it's retrograde bit. This would throw any imaging out.

Found this: Saturn retrograde lasts from 18 February 2013 to 8 July 2013.

That wouldn't affect webcam imaging Ronin. The apparent motion of Saturn isn't that fast in 1/10th of a second!

[dephelis]

Sorry for the double post, but I was distracted by Ronin's post.

Recently I've been taking all my images using an IR pass filter to cut through the seeing. I've been finding that it makes quite a difference.

[Stargazer33]

Thanks for all the replies and suggestions.

I will definitely stick with it and each time I manage to get out I will try to tweek one or two things and see how that effects the results.

I'm not sure if my Neodymium filter is IR pass or not - will have to look that one up! I was also thinking of doing an image run with a red filter in place as I so often read on here that the red light isn't effected as much by atmospherics. If I get much better/clearer images (despite them having a red cast) then I could be sure that it was atmospherics/altitude of the target. I have just had a thought (lonely I know but another one may come along later to join it! ), if I do a standard image run - colour and another image run with a red filter in place; would stacking them together give me an RGB image with an improved sharpness due to the extra red light image in the stack?

Ronin: I meant that my imaging is going backwards i.e. getting worse. Not that Saturn was moving backwards or that my mount was tracking in the wrong direction, but an interesting suggestion when it is moving retrograde. I would think that the stacking software would handle that though, just as it does when the target moves due to poor tracking/mount alignment.

I am just going to have to get my work brain out when I am imaging and gradually eliminate possible causes of the 'fault' to leave me with the most plausible answer.

Thanks again for all the help/support. You guys are great as always!

[dephelis]

Thanks for all the replies and suggestions.

I will definitely stick with it and each time I manage to get out I will try to tweek one or two things and see how that effects the results.

I'm not sure if my Neodymium filter is IR pass or not - will have to look that one up! I was also thinking of doing an image run with a red filter in place as I so often read on here that the red light isn't effected as much by atmospherics. If I get much better/clearer images (despite them having a red cast) then I could be sure that it was atmospherics/altitude of the target. I have just had a thought (lonely I know but another one may come along later to join it! ), if I do a standard image run - colour and another image run with a red filter in place; would stacking them together give me an RGB image with an improved sharpness due to the extra red light image in the stack?

Ronin: I meant that my imaging is going backwards i.e. getting worse. Not that Saturn was moving backwards or that my mount was tracking in the wrong direction, but an interesting suggestion when it is moving retrograde. I would think that the stacking software would handle that though, just as it does when the target moves due to poor tracking/mount alignment.

I am just going to have to get my work brain out when I am imaging and gradually eliminate possible causes of the 'fault' to leave me with the most plausible answer.

Thanks again for all the help/support. You guys are great as always!

The Baader Neodymium is an IR and UV Cut filter so won't help in this case. I have to admit I'm not sure how the various filters will work with the SPC as I had already upgraded and given mine to a friend before I got the filters.

I don't doubt that someone who knows will be along in a moment though

[todd8137]

As every one says seeing is not great in these images ,but what a start you have had ,am sure you might get a few more try as this year hoes if not just think she will be back next year ,and if you kept a log of your settings ect you will be good to go ,i like to use a mono cam or planets and the moon,great-start and heres always next year

pat

[Stargazer33]

Thanks dephelis, I will probably keep the neo filter on just to help with the LP here where I live.

Thanks Todd! I hope Saturn isn't going anywhere any time soon! I will keep plugging away any opportunity I get.

I think part of my problem is that I am still not 100 % sure of my scope from when I took the corrector plate off earlier this year to put the Fastar system back on after foolishly removing it to see how it came off!!!

Last night I quickly set the scope up and imaged an aerial that was probably about 200 metres away. I used the same set up as the other night but without the 2.5x barlow lens. I stacked the images in RS6 and this is what I got:

I know it was only 200 metres away and not 1.4 billion km but the image looks good to me. Focus was slightly off as it was difficult to see the screen of the laptop in the bright light.

I guess that means that my poor images of Saturn recently have mainly been down to atmospherics, which is reassuring.