one for pol - jupiter

[devilgas]

the following image was created from a webcam movie. the webcam is only vga resolution, so the resulting image was quite small. it was shot using my 1100mm telescope with a 2x 'barlow' lens. the camera was a phillips spc900.
the movie was 2min in length @ 5fps, producing about 580 frames (some frames were dropped during capture). processed using a piece of software called registax. the final image has also been upsized by 1.5x



why webcam? trying to shoot planets using stills from a dSLR is very challenging. it's not impossible, but is very time consuming due to the shear number of photos that are required. a single image would be very fuzzy, showing little detail. so lots of images are needed so that they can be stacked.

the image - as far as i'm concerned, it's ok. i'm impressed with the amount of detail that has come from the stacking process, however the small image size is disappointing. i need to find a way of getting more magnification - probably using afocal projection through an eyepiece.

[Pol]

Re: one for pol - jupiter

Thanks!

That's better than an 'ok' image, it's superb! Small maybe but the detail and colours look fantastic.

You must surely be thrilled with it and it certainly looks as though you're getting to grips with the webcam techniques. Your picci compares very favourably to a lot I've looked at. It's actually very clear and well defined - barely any fuzz at all, especially as it's been upsized too.

Good luck with the eyepiece. I'm fairly confident you'll suss it and get the magnification and image size you're after.

I'll have a look at that 'registax' software and I'll also prod David into getting something sorted about the webcam. We haven't even had a suitable night outside so far - too cloudy or too cold, visitors or whatever, always something.

You've done an excellent job. I'm seriously impressed, especially as I realise more and more how difficult it is to get this sort of image at all, let alone one as clear and as detailed as yours.

Well done, Dave.

Pol

[Pol]

Re: one for pol - jupiter

Erm ... I've just been looking at Registax and I'm even more impressed by what you're achieving!

I think I'm probably a tad too thick for it.

Pol

[Pops]

Re: one for pol - jupiter

That is very impressive. The sort of shot one only see's in magazines.

[Barr1e]

Re: one for pol - jupiter

Pleasing I have had time to look closely at your image (home improvements this morning).

It is quite incredible.

Thanks for the explanation Dave, so much effort and in this case rewarded.

(Thanks for the comments on my moon picture.)

Regards. Barrie

[devilgas]

Re: one for pol - jupiter

Erm ... I've just been looking at Registax and I'm even more impressed by what you're achieving!

I think I'm probably a tad too thick for it.

Pol

uhhh, yeah. it's not the easiest. i deffo prefer v5 over v6. at the moment, i'm just using the defaults until i get to the wavelets section as that's quite an important step. currently, for the wavelets, i set the last slider to about halfway, with each slider above that being half of the previous setting. so, slider 6 has the most change, slider 5 less so etc. it's then a case of tweaking until you get an image that doesn't look too overprocessed. getting the best from registax seems a bit of a black art

i was a bit disappointed with the image size. i may see if i can double up on the barlow lenses (i have 2) before i start messing with afocal projection.

all a learning curve

[Pol]

Re: one for pol - jupiter

I'd have thought it would definitely worth a try doubling up on the Barlow as it wouldn't be too expensive and might save you a lot of extra work and faffing about.

Hopefully doubling up won't cause too much image deterioration either - especially if you can become a whizzkid with Regimax. You can do it, Dave. I probably couldn't, but you can!

The outline of your Jupiter picci is excellent imo. Did you need to leave the 'scope outside for long before using it? Was it a warmer night than these recent frosty nights? There doesn't appear to be too much evidence of convection inteference visible.

It's a great picci. Small is beautiful, it's the quality that counts.


Pol

[Donald]

Re: one for pol - jupiter

Amazing shot, well done.
Donald.

[Ian]

Re: one for pol - jupiter

Could you not use the movie function in a DSLR and stack stills from that? 1920x1080 is better than 640x480

Ian

[devilgas]

Re: one for pol - jupiter

Could you not use the movie function in a DSLR and stack stills from that? 1920x1080 is better than 640x480

Ian

you could, but i couldn't. i don't have a dslr that shoots video

i think you'd still end up with a similar size image due to the sensor sizes. the sensor on the webcam is 1/4" (3.2mm x 2.4mm) compared to say a canon D60 which is 22mm x 15mm. the physical image presented by the telescope (using prime focus) doesn't change, with the planet being the same area regardless of what it is being projected onto. the point of focus should be the same for both types of sensor, so you shouldn't get any free magnification by moving the sensor further away.

looking at the numbers (i'm assuming that the slr will combine [bin] pixels to get the image from 18mp 2mp) the dslr gets 1920 px from the 22mm sensor width (about 90px/mm)
the webcam gets 640px into 3.2mm (200px/mm). so, if anything, the larger sensor will give an even smaller image, but having not tried this, i can't confirm or deny. i'd certainly like to give it a go though!

assuming the maths i have above actually converts to real life, you'd be better shooting 18mp stills (230px/mm) and stacking those. you then get into the realms of shutter shake etc. i know the astro forums & various books i have say webcams for planetary, dslr for deep sky. not sure if they take into account HD video on newer slrs though.

[devilgas]

Re: one for pol - jupiter

That is very impressive. The sort of shot one only see's in magazines.

thanks pops, but that image would never make a magazine

looking forward to trying out saturn when it's visible again.

[devilgas]

Re: one for pol - jupiter

The outline of your Jupiter picci is excellent imo. Did you need to leave the 'scope outside for long before using it? Was it a warmer night than these recent frosty nights? There doesn't appear to be too much evidence of convection inteference visible.

Pol

my setup involves getting the OTA (tube) out first so it gets chance to cool down whilst i set the rest of the kit up. usually takes about 20mins before i can start imaging. my main imaging goal on friday was nebulae, so i started by testing the webcam on jupiter, mainly to see if it would work (it's been re-housed so i can use it on the solar scope). it got pretty cold on friday after i'd been outside for about 4 hrs or so - the grass was frozen by the time i'd called it quits.

i think registax gets rid of a lot of convection effects. certainly when you are watching the capture, the image dances about quite a bit. the registration process sorts that out really well though.

[Pol]

Re: one for pol - jupiter

my setup involves getting the OTA (tube) out first so it gets chance to cool down whilst i set the rest of the kit up. usually takes about 20mins before i can start imaging. my main imaging goal on friday was nebulae, so i started by testing the webcam on jupiter, mainly to see if it would work (it's been re-housed so i can use it on the solar scope). it got pretty cold on friday after i'd been outside for about 4 hrs or so - the grass was frozen by the time i'd called it quits.

I think registax gets rid of a lot of convection effects. certainly when you are watching the capture, the image dances about quite a bit. the registration process sorts that out really well though.

Thanks for all that. I can't see myself staying out in the cold as long as that but I'd happily pop out and have a good look when David's got everything in sight and focus.

Obviously we're gonns have to be getting to grips with registax too at some point. He hasn't even got the webcam yet though he has a site link where they have them in stock now, complete with conversion instructions. I think he's ordering one as I type. (He reads some of the astro forums a lot more than me).

Your pics and your advice and tips really motivate him (not to mention my endless prodding).

Pol

[devilgas]

Re: one for pol - jupiter

had another go tonight with a pair of 2x barlow's. they worked, but as i was helping my nephew with maths didn't get outside until 2130. then had to wait for jupiter to clear the neighbours tree, so didn't start imaging it until it was low in the sky. the results weren't good, but as a proof of concept, it was fine. think i'll just buy a single 5x barlow.

i did get to finally put the hydrogen alpha sensitive 20d through its paces though. got a totally new take on the orion nebula. will try and get them processed this week. focusing was a PITA (it's a modified 20D rather than the 20Da which has live view) and took a few mins of trial and error to get dialled in.

haven't seen tonights stargazing live as i was outside doing my own stargazing got it sky'd so will have a butchers tomorrow (unless we've got clear skies again....want to get the great red spot imaged). if they had the same skies i just enjoyed, then it should have been a cracking programme.

[devilgas]

Re: one for pol - jupiter

It is quite incredible.

Thanks for the explanation Dave, so much effort and in this case rewarded.

thanks barrie! i'm learning very quickly that astro imaging involves quite a bit of effort, quite a bit of kit and a steep learning curve in post processing. i'm getting there slowly but surely. just need to kill all of the streetlights in south wales now so i can have DARK skies so i can image the fainter nebulae