PLEASE help with Jupiter Imaging!

[Costas Soler 53]

hi!

I'm using my school's 17" telescope and a Nikon D3200 to record video from Jupiter to stack. The scope I'm using is f/6.8, and I'm using two 2.5 luminos barlow lenses on it, which blow Jupiter up and I think give me around a focal ratio of f/43. The images I've included were captured with a video consisting of 1/30 second exposures at ISO 800. I'm pretty sure I'm not getting the most out of my camera and scope right now, I'm pretty sure I've seen other DSLR users get WAAAY finer detail with similar cameras on much smaller scopes. PLEASE let me know if you have any suggestions... I'll be imaging tonight again, and I'll be sure to let you know how it goes!

[elliot 137]

Not sure of a few things here prob best to get cleared up first.  17" is a massive scope, and to be f6.8 it would need to be ....(errr)....3 meters long!  Is it?

[Costas Soler 53]

It's a 17" CDK telescope, so the light takes a trip from the primary to the secondary, then from the secondary to the camera/eyepiece. Those two trips do add to about 3 meters, but luckily the scope can be a little smaller. It is still huge though, and requires a dome!!

Here's a picture of it, with me to scale:

[elliot 137]

Ooh wow. That's a cracking bit of kit. Do you know what I'm going to do now? I'm going to stand down and let seasoned SGLers take over to diagnose your problem.

[ronin 3,795]

Two barlows is not a great idea they are very likely just degrading the image, I would try a single powermate at around 2.5x or 3x to reduce the focal length from what you had which I suspect is now too long for a stable image to be captured. I would not go for a 5x powermate, again suspect too much even if it is less then the 2 barlows.

When talking to an imager here about using a 16" ODK I said it would be a good option for planetary imaging, his response was "Definately not", and that it would be much better for long exposure DSO imaging. He has a lot of knowledge concerning imaging and I therefore suspect that when he said not the best he was correct. Seems it might look like an SCT but not necessarily the same.

As I am sure this has arisen previously you should not be stacking all the frames. The wording used is a bit misleading as it is talked of capturing a video then stacking the captured video, the identifing, selecting and stacking only the good frames is overlooked. A good frame and a bad frame stacked together make a mediocre image. You select the "best" one - often by manual visual examination - then get the software to stack the 300 or 500 that best match that good one. In effect you select and stack only "good" frames.

How long was the video? It is said that you should go no longer then 90 seconds with Jupiter. As it rotates fast then after about 90 seconds the features have moved too much to be accurately realigned, so you end up with a "smeared" image and so lack of definition. The GRS is no longer the Great Red Spot but the Great Red Streak.

Assuming this is correct then Jupiter sort of lends itself to people taking a 60 second video and seeing who gets a good result. At an Astro Imaging course this was what someone did, people took a 60 second video for themselves and then off home to play/process. Made a difference to someone talking about imaging, they had the chance to take a video, save it, then process in one of the free stacking packages.

[wornish 345]

I am no expert but as a minimum pre process the video using PIPP  and enable frame selection based on quality to ensure you only use the best frames for the next phase which is stacking.  Then use registax or autostakkert to stack the best ones.

 

[newbie alert 501]

I'd suggest a planetary camera..dslr has a wider field in comparison..is you stack in autostackart and de rotate in windupos..

With a 17 inch scope I'd suggest  30-40 secs

[Costas Soler 53]

Thanks everyone! I took your advice, and used only one Barlow lens. I also used only 1 minute captures, and I think it helped a lot. I made this animation over a series of captures last night until the fog rolled in. As you can see, the quality is vastly improved. Thanks a lot!!

18066103_633290853523501_6965660471269523456_n.mp4