i am trying to improve my planetary imaging with Jupiter out in full force in recent times. the only problem is that i cant seem to get a decent image. i record video on my QHY5Lii and then stack it in registax, i have tried both my 2x and 5X televue barlows/powermates to try and get more detail while using my BT 250 newt on an NEQ6 mount. but no matter how hard i try i cant get a really clear image. looking through the data i see that the atmosphere is jumping around between every frame (taken at the highest practical frame rate). is it just really rare to get good seeing conditions? or is the fact that i am taking it from Sydney going to mean that i will never get decent seeing conditions, i.e. do cities significantly disrupt the seeing conditions?
I find a cheap webcam does the best job.[mine was $15 in K Mart.]
The 5x will only make the atmospheric instability worse, except on
the rare occasions when the atmosphere is really stable.
raymo
I was looking at Jupiter last night through my 16" dob and the atmospheric wobble was noticed. It's not just a city effect and the heat at ths time of year is a part of it. Because Jupiter is low in the NE you will be looking through much more atmosphere than if it was at
The zenith. I could not push much beyond 200x visually last night, just enough to see the great red spot easily. It your keen for the best possible imaging of Jupiter this month then I would suggest you come along for a couple of days to the Bretti Star Party camp around the new moon (16th - 21st). Bretti s a great dark site but even there best results are found later in the night when the heat rising from the ground as disapated.
I am looking at it now with 8 inch Dob, its like a heat haze wobble as its rising?10mm doesn't improve it much, just barely see faint 2 brown/tan stripes,4 moons almost horizontal alignment.Moon will be up at 10pm
Last edited by creeksky; 08-02-2015 at 08:28 PM.
Reason: heathaze wobble
apart from seeing issues, have you checked your collimation is right at the sweet spot? I found that after collimating with a Cheshire eyepiece, visuals improved by a long shot.
i thought the issue might be collimation but i re-collimated last night and still had the issues, besides when i started going through frame by frame in registax it was clear that the atmosphere was extremely volatile. i have attached a couple of images for you to have a look at, this is the best i have from the past 1.5 years. i am not saying these are horrible but i do expect a lot better. i am just wondering if anyone gets good results from a city or whether i need to take my shots elsewhere for higher quality images
only guessing you're not processing with a properly colour calibrated monitor and workflow. but yes its difficult to get much detail, getting a good focus can be tricky and yes you're data will look like the planet is swimming under water. all normal with my experience.
one direction i can point my scope has a large road 0.5km away and once i get focus acceptable to record and i hear a car on that road i can count to 20 and my image washes away as the disturbed warmer air rises to cross my line of sight. so i learnt to keep an ear out and record only once there was no traffic. likewise any breeze brings thermal differences to the air turbulence. don't forget cooldown on the scope too.
processing wise are you discarding low quality frames, refining alignments to get the most from your data?
We do get some decent nights here in Sydney, just not in the summer I have the same camera and you should expect good results from it with a decent night, probably in autumn or winter...
We do get some decent nights here in Sydney, just not in the summer I have the same camera and you should expect good results from it with a decent night, probably in autumn or winter...
only guessing you're not processing with a properly colour calibrated monitor and workflow. but yes its difficult to get much detail, getting a good focus can be tricky and yes you're data will look like the planet is swimming under water. all normal with my experience.
processing wise are you discarding low quality frames, refining alignments to get the most from your data?
I still feel like an absolute newb so i have a lot to learn on the processing front. i do discard bad frames in Registax, but i don't go through frame by frame, i use the stackgraph to choose the better images.
ok, I'll chime in here, seeing that staying up tonight to take images of Jupiter has been cancelled due to the clouds. You need to do a couple of things before you start imaging:
1. Seeing check - use skippy weather to get the seeing forecast. It does not matter that you live in a big city. I am 5.5km from the Melbourne CBD and here are some of the results this year: https://www.flickr.com/photos/johnka...57620534659372
If the stars are twinking like mad leave it for another night.
2. You need to cool down your mirror - does it have a fan? Leave it outside several hours before imaging, use anything you can to get the temperature mirror down. You have a lot glass in a 10". Even putting on a domestic air conditioner inside to cool the mirror works well. Get a weather thermometer and attach to the side of the mirror and try and get the mirror to ambient before imaging.
3. Collimation - must be perfect. Point the scope to Jove, get tracking, and then collimate before you image.
4. Make sure you get 70% plus on the histogram with your exposures. Your images look faint to me. Crank up the gain and try and get the highest FPS you can - this will freeze the seeing and you will get good frames.
5. Forget about Registax for stacking. Use Autostakkert2 with multi point aligning. Then throw it into Registax for wavelets. Then get a free copy of Astra Image and do some deconvolution. The some contrast and noise reduction in Photoshop or something similar.
6. IF you want to get more funky - assume you have a colour camera - break the avs into RGB using a software program, and then process seperatelty and recombine.
I have the same camera and you should expect good results from it with a decent night, probably in autumn or winter...
