Still having problems with Saturn

[TheThing]

Out for a couple of hours last night trying to image Saturn, but still not having great success!

I was using the Soligor 152mm (6") f5 Newt on a Tal motorised pier. Tracking after PA was pretty good with Saturn holding steady in the FOV for 5 - 6 mins. The camera was a Meade LPi set to 'planet' with an Astro Engineering 1.6x screwed into it giving approx 200x magnification.

The LPi captured between 200 and 350 frames (after disposing of duff ones) and these were automatically stacked by Meade's AutoSuite. The Gain was set right down to 1 (from 100) and the offset to between 20 and 45 (again from 100).

I had double checked focus by using my new AstroZap 'mask' on Acturus and it was pretty much spot on (although one shot is clearly out of focus when I fiddled to see if it would make a difference!) The scope was then moved onto Saturn without being re-focused, but also double checked with a parfocal 26mm Meade plossl.

Collimation seemed spot on when using the AstroZap - the middle line was clearly central when focused on Acturus.

I'm probably missing something simple, so I throw myself at the mercy of the more experienced imagers here. Can you help please?

The night was a total waste as I still had good fun imaging. I also got to use my True Technologies filter wheel on the 4SE for some visual observing of Saturn and seeing how the different filters I have help/hinder viewing this object.

[j.finn]

well my setup is diffrent to yours but the images are the same i think we have the same problem sorry i cant help you as am needing help my self.

good luck

[Demonperformer]

I'm no expert, and I haven't used that particular camera or program, but they look overexposed to me. This seems to be a common problem. Do you have a preview screen? If so, I guess you are setting the shutter speed so that it looks about right on the screen. Try reducing the shutter speed by 1 stop and capturing an avi. Maybe even do another one reduced by another stop (although this may be too dim).

I have obtained my best planet pics (using neximager/sharpcap/registax) by ending up with an avi that you can only just see a 'ghost' image on each frame, then upping the contrast in final processing, eg Stargazers Lounge - Demonperformer's Album: Planets - Picture

HTH

[Parallax]

As DP has said, it looks like it is overexposed and you need to turn the wick down a bit.

Attached is a single frame from an AVI of mine showing the sort of brightness you should be aiming at. Also attached is the final processed image. This was taken about 2 years ago, with a Philips webcam, 8" reflector and 3x barlow, but I didn't note the webcam settings I'm afraid.

Steve

[riklaunim]

You need at least 2x Barlow (up 4x) to get good scale of the planet. Your images are slightly overexposed and have good focus except one with splitted ring - you shoul check, fix focus on the live view from the camera. You have to also keep in mind that LPI have a CMOS sensor with quite big pixels - the images won't be pretty.

[Cornelius Varley]

Try capturing an AVI video using Wxastrocapture and then process in Registax.

Peter

[Space Cowboy]

Basically you need to bump up the magnification with a barlow lens and have a shutter speed of 1/25 or 1/33 of a sec. The bigger the image the better the camera can cope with the exposure. Needs to be at least 400x mag preferably 600x.

[TheThing]

Ok, thanks folks. Doesn't seem too complicated....except, the LPi doesn't give me shuuter speeds of 1/25 etc, it does them as decimals! The preset is 1 (which I assume is 1 second?) so I should be looking to reduce them to 0.333 or 0.250, is that right?

[riklaunim]

Just look at the live view from the camera - the planet shouldn't be white or very dark. Set the exposure so it gives good ilumination of the planet

[greenkat]

Hi Thing

I agree with overexposure.

On the Meade envisage, keep the gain at 100 & offset at 50

Yes take the exposure down to .33 or .25, then untick the auto contrast box and adjust the histogram untill it is all green, then adjust the exposure up or down untill it looks right.

I use envisage with the DSI camera and it always over exposes planets.

I took this a year or so ago using Envusage

Hope this helps and keep trying

[TheThing]

Brilliant advise from all, as always!

I've printed this topic off so I can refer to it at the camera.

Thank you kindly.

[TheThing]

Managed to get out for a little while last night. Unfortunately, it clouded over pretty quickly, so I didn't get much time to experiment! Managed to get these thru a Tal 2x Barlow, so size is getting better. I've sourced a 4x Imagemate, so hopefully that'll help too.

This is taken at 1/33 (0.330) exposure. Still over exposed, but getting better. Focus is a little out, but I didn't have time to use the Astrozap!

This is at 1/25 (0.250). Still over exposed and soft focus, but I feel I'm heading in the right direction at last!

[atomic7732]

If my images were half that good, I'd be happy! I am having problems too, so should I make a new thread?

[Psychobilly]

Hi Thing...

0.250 is 1/4s not 1/25... 1/25s would be 0.040 the displayed value is the exposure in decimal seconds

Peter...

[brantuk]

Well spotted Psycho - that's exactly what I was thinking lol

[TheThing]

Peter,

Thanks for that! I was thinking along decimal lines and not seconds, but it makes perfect sense now you've said it!

I'll try that out next time I get a chance.