Imaging Jupiter

[Captain Tweaky]

I have a Meade LX90-8" ACF, a ZWO ASI120MC and a Revelation x2.5 Barlow and a huge number of disappointing images. After taking a video using SharpCap, I either use PIPP, A!S2, Registax 6, Photoshop CS3 or a combination of them. No matter how I post process I can normally end-up with the same kind of result in terms of quality of image. If, as a result of seeing my images, anyone has any suggestions as to how I can improve I really should be most grateful. I recently bought a set of Bob's Knobs and collimated the 'scope, but the improvement was nominal. The images of Jupiter all started the same size, the smaller ones have been reduced purely to clarify the image - they were that bad!!!!! And there are plenty more where these came from!! 

[Captain Tweaky]

It did just occur to me to give some idea of the videos. For the most part they are 2,000 frames at somewhere around 20fps. The image is created from anywhere between 25-60% of the frames with little realistic improvement in the end result. By the time I have managed to get as far as wavelets in Registax 6, the image I normally have to deal with looks something like this:

Capture 26_02_2015 22_13_58_g3_b3_ap7.tif

[knobby]

Not criticising , they're really not that bad ! ... Are you using a region of interest as 20 fps seems very slow for the asi , I capture using 640 x 480 at about 50 fps .

Looking at the moons I'd say focus is off a tad ? Have you tried a clothes peg on the focus knob ?

Try getting the frame rate up and capture as much as possible in 1.5 to 2 minutes .

Lastly I have the same Barlow and I feel f25 is too much for an 8" sct unless seeing is spot on

Good luck and keep at it

[Captain Tweaky]

Knobby many thanks for your input. I've tried using 640x480 but the rig allows the planet to drift-off - I've not done any PEC training, but it seems more like backlash that causes the issue. The focus seems to be very difficult to achieve any great accuracy - the image is always blurred. It just seems to be a case of minimising the blur. I use a Revelation Crayford focuser which allows for very accurate movement, but I still never manage to achieve a properly focused image.

I do have an Antares 2" x1.6 Barlow so I may try 'fiddling' about with that - providing I can get enough travel to achieve focus at all!

I shall persevere, but it is getting quite disappointing when I see some excellent results even with an 8" RC. 

[knobby]

Definitely try the Antares, has a great reputation and f16 will be better

[PeterCPC]

Have you checked the collimation? You will never achieve great focus if the collimation is out - I had this problem. Do you use a Bahtinov mask?

Peter

[Captain Tweaky]

Peter - yes, as I said in the beginning, I bought some Bob's Knobs and collimated the 'scope just recently, but the improvement was nominal.

The image is too 'fuzzy' to achieve an accurate focus with the Bahtinov mask - the planet moves 'in and out' most of the time so it is only possible to stop focusing at a sort of 'mean' position. I have taken to cooling the 'scope for about 2 hours outside beforehand, but this again only seems to make a nominal difference.

I am wondering what is the best image that I can expect to achieve with my set-up? I have seen some quite detailed images from Celestron 9.25" and even an 8" RC so I imagine that I should be able to get very much better than the images above. The very best I have been able to achieve is as follows, but this has involved a ridiculous amount of processing in Photoshop and there is still very little actual detail:

[PeterCPC]

It sounds like you are trying to use the Bahtinov mask on Jupiter itself but that will not work. I focus on a nearby star - with Jupiter I used Procyon to get focus and then swing around to Jupiter. Some people say they focus on the moons of Jupiter but I have never been able to do that.

Peter

[leelee970]

I've not used a similar scope to your set up but collimation is really important,as is focus. You also really need to let the scope cool down before even attempting to use it.

Mine is in an observatory so I don't often have this issue. but I always check collimation. I then focus on a near by bright star using a Bahtinov mask before returning to the planet. 

(remember to remove the mask). You'll need to increase the gain and/or exposure of the camera for focusing on the star which makes things easier.

The number of frames you capture will have a major influence on final image quality. So look to decrease the ROI which will increase your frame rate.

The one thing you don't have control of is the "seeing" and this has the biggest influence on an image run.

remember, practice and you will be rewarded.

Lee

[Grotemobile]

Hi I have got a similar set & I am getting about the same. 

Try screwing the end of the barlow, into the end of the cam.

This will give you 1.5x.Yours is a lot better than mine.

This is the best I have been able to get.

So you are doing well.No barlow was used in mine. 

Gives you some idea, what other people are getting.

Steve

juipter XX_00000-PART1.bmp

Juipter 07#03#15_00000-PART1.bmp

[Captain Tweaky]

PeterCPC - having had quite a lot of experience imaging DSOs I did know not to use the Bahtinov mask on Jupiter itself - I tried using one of the Moons. As you suggest, this is not particularly successful. I shall maybe try something like Procyon with high gain.

leelee970 - as I said, I do leave the 'scope outside for around 2 hours before using it. After collimation about 2 weeks ago there was no substantial difference in the ability to focus or the image quality. As for the ROI and fps - if I reduce the image size to 640x480 for example, the mount has a tendency to allow the planet to drift-off the edge of the frame. This would seem to be an issue with the mount I guess. I have found that 960x960 allows approximately 25fps and the planet usually remains within the frame.

Grotemobile - I was very interested to see your images as they are remarkably similar to those that I achieve before using Wavelets in Registax 6 - albeit mine is with a x2.5 Barlow so consequently a fair bit larger.

[Grotemobile]

I see that you use Registax 6.I am still using 5. 

My main problem is just the streetlights.

This is about the best I have got. 

This was 80% of 3000 frames.To

much I think.

Steve

[Twisted Lip]

<disclaimer>

Firstly I should state I am by no means a planetary imaging expert!

</disclaimer>

...but as I haven't had much time to get out and do any DSO stuff I turned my hand to it a bit more and so have come across a few issues like this too.

1. I moved to FireCapture as - on the whole - I found the process much easier to control than anything else. It'll also let you stabilise the image in preview in a controlled fashion. Whilst this isn't unique in capture, I found that it did give me a massive insight as to how much seeing was affecting the frames (certainly on most of my captures you can really see it move in and out of focus).

2. Seeing is more important than I ever thought it was! With DSO I generally only worry about the cloud and I had to learn the hard way that it effects the output hugely Not a lot you can do with this one but I did find when it was bad I just had to drop the 2.5x Powermate and go prime.

3. Focusing was a pain. I tried the BM with limited luck and found that over time (as you would expect) the image would move in and out of focus slightly anyway. In the end I plumped for a new Moonlite focuser and I have to say I've found it a lot easier. Are my images any better? Marginally - but the reason is probably due to me being rubbish lol Its certainly a lot easier to correct when you see the image move out of focus for whatever reason.

4. Tracking - you say the image is moving across the screen relatively quickly? The HEQ5 is a great mount so probably shouldn't give too much drift? Maybe looking a a polar aligning error perhaps? Also, how are you controlling the mount (EQMOD, synscan, etc?)

5. Luck - I wish you the best of it! And if you get some please send some of it back this way!

Cheers

Will

[Captain Tweaky]

Will - Thank you kindly for your thoughts. In many respects they go along with my own experience and it's good to know I'm not alone with what I've been struggling. I had forgotten about Firecapture in my efforts to obtain increased FPS in SharpCap - I think I need to give it a go. Your point 4 refers to the HEQ5 which I only use for DSOs. The LX90 is mounted on its own alt-az mount and there can be issues with Periodic Error Correction and what I refer to as backlash.

I'm interested to note that you also have a WO GTF81. It did not go down well in the UK so I'm pleased to see that I'm not the only person who has one!! 

[Twisted Lip]

Will - Thank you kindly for your thoughts. In many respects they go along with my own experience and it's good to know I'm not alone with what I've been struggling. I had forgotten about Firecapture in my efforts to obtain increased FPS in SharpCap - I think I need to give it a go. Your point 4 refers to the HEQ5 which I only use for DSOs. The LX90 is mounted on its own alt-az mount and there can be issues with Periodic Error Correction and what I refer to as backlash.

I'm interested to note that you also have a WO GTF81. It did not go down well in the UK so I'm pleased to see that I'm not the only person who has one!! 

Ah, my apologies! I assumed you were using the HEQ5 for your planetary mount also. I don't have a lot of experience with the standard LX90 mount but I'd be surprised if any errors couldn't be overcome with WinJUPOS perhaps (for Jupiter only of course)? Might be worth a crack at least.

I have to admit I don't know why it took me so long to move to FireCapture, its such a breeze to use and for some reason seems to get better results than the standard software that comes with the Point Grey cameras! I have an added issue of filters and filter wheel too which adds to the processing time

Yes I never really understood the disquiet about the WO. I've always found it second to none in its range (although I think the main problems were with the GT81 rather than the GTF's). How did you get on with it?

WIll

[Captain Tweaky]

Yes I never really understood the disquiet about the WO. I've always found it second to none in its range (although I think the main problems were with the GT81 rather than the GTF's). How did you get on with it?

WIll

There were collimation issues with the GTF81 that was tested for Sky@Night apparently. Also there is debate over the use of a focal reducer conflicting with the built in field flattener. All-in-all it went up like a lead balloon with the British astronomer. Mine does have a very minor aberration that on close inspection hints at distortion in stars, but as I only have an Atrik 314L+ this issue is not painfully obvious. As I purchased it with a substantial discount I'm not unhappy with it and it is very nicely made.