(Very) early red channel Jupiter...

[Kokatha man]

Posted the original (smaller) scale image on CN yesterday.....just a quick repro at a bit larger scale using R6 after we got home this afternoon.....a bit grainier etc at this scale, but I thought it worth the exercise.

I took this red channel capture just before 7.00 am local time, about 10 minutes before sunrise...Jove was still very low and the seeing was barely adequate, but I wanted to see what was happening with the SEB etc, and I think that despite its inadequacies the image still displays a fair amount of detail.....

I also captured an iR742nM the same morning but honestly think that using that filter presents more difficulties than benefits, regardless of the aperture one is using.....the fps rates just too low imho to counter the effects of atmospherics at such poor elevations etc.

As I said on the other forum, at least with the 100fps I used you get to "freeze" seeing dificulties a bit - although I have to admit that not being able to get a really sharp focus onscreen is what probably held this image back as much as anything else we had to deal with..!

[Space Cowboy]

Congratulations on getting the first Jupiter of the new season! Excellent detail, SEB is certainly back with a vengeance! What Alt was this at btw? Barley above ankle hight here in Olde Englande.

[Kokatha man]

.....much the same here Stuart: without checking, off the top of my head I'd say most probably around 25 degrees or so..!

I've just received a reply email from John Rogers of the BAA re my image remarking about the STZ's darkening apropos the GRS.

This apparition you folks in the Nthn. Hemisphere should be getting much better opportunities with Jupiter compared to previous years!

[4lefts]

Nice pic! It's great to see Jupiter back. Can I ask what the reason is for just doing red? Time pressures? I'm new to all this.

Thanks.

[Kokatha man]

Nice pic! It's great to see Jupiter back. Can I ask what the reason is for just doing red? Time pressures? I'm new to all this.

Thanks.

Hi 4l.....as you'd probably know already, rgb (colour) imaging with a mono camera involves taking 3 seperate captures using different filters in front of the cam (r,g & b!) to create the composite colour image during processing...

If you use an electric filter wheel which has a revolving turret (like the old 6-shooters!) it makes the change from one filter to the next much easier and quicker ('cos you have to be quick to get all of the different channel captures done within tight time constraints!)

We also have the ability to have other filters in the chamber (mine's a 7-shooter!) such as iR and luminance (essentially a clear filter).

You can see already why "one-shot" colour cameras are much simpler to operate with their inbuilt bayer matrix array of "filters" over the cam sensor, but mono does have benefits in creating coloured end-images also...

As to my using a red filter only to create a mono image here (ie, using only one colour channel filter for an image only gives you this b&w result).....the camera I use (Flea3) is not only especially sensitive in the red spectrum, but it can operate at very high framerates (frames per second) and especially so in red due to the aforementioned sensitivity.....I recorded/captured thie video that I made this image from at 100 frames per second!

At such high framerates the effects of atmospheric distortion (which are very high when a planet is at these low elevations above the horizon) are minimilaised.....it's termed "freezing the seeing" as "seeing" is a measure of how bad (or more importantly, good) the sky is at any one elevation, and any particular time of any night.

Seeing is extremely important for planetary imaging where folks are usually using long focal lengths. (high magnification/large image scales)

Hope this helps a bit....!

[Jupiterholic]

sorry if I've missed this in the thread here.. but did you get the blue and the green? I'm dying to see this in colour.

100 frames per second... I'm almost drooling.

[4lefts]

thanks for the information! i didn't realise some cameras where more sensitive to some colours than others. i would have thought that, without a bayer matrix, they would be equally sensitive to all colours. interesting.

do i remember reading that with jupiter you have about 90 seconds or so to capture your data before you start to get blurring from the rotation of the planet? so if you wanted to do colour, you'd have do each of the 3 filters in that time? and i guess you'd have to do more of green and blue if the camera is more sensitive to red?

out of interest, how many frames did you capture altoghether, and what the ratio of ones you used to ones you ditched in the final stack?

sorry for all the questions!

thanks,

stephen.

[Kokatha man]

With Jupiter the "accepted" timespan is 3 minutes, meaning 180 seconds to do all of the channel captures: as you've noted, the Flea3 is more sensitive in red and thus you can get a faster framerate...and so can image for a shorter span than merely dividing that 180 secs by 3.....which is helpfull as the green and even more so with the blue (most affected by Earth's atmosphere) you need to capture at slower fps for similar exposure levels.....

Just about all cameras I have used are more sensitive in the red spectrum as compared to the other channels, even the one-shot colour cams that have bayer matrixes with 50% of the sensor covered with green and 25% each for red and blue.....I've gone from a Toucam 840k to a DBK21, and now the Flea3...

Trying to get anything out of Jupiter at such low elevations this early in the current (new) apparition means a high attrition rate to get an acceptable stack for further processing.....I captured approximately 18000 frames (180secs x 100fps) and ended up with 2000 that I determined were of sufficient quality apropos the frame I used as the reference frame.....

J/holic, this capture was a dedicated red channel capture (ie, the full 3 minutes was used on red) but I did an rgb a bit later but the effects of atmospheric distortion created a blue image considerably smaller than either the red or green making it almost impossible to rgb combine in AstaImage.....I might have a play around tonight with them in CS4 where it should be a bit easier to get blue the same size as the other 2 for an rgb result.....

[4lefts]

thanks again. i'm really interested in planetary photography, and it's nice to see someone using a firewire camera. i'm on a mac, so it's quite interesting to me, having firewire as standard.

i'd never heard of the flea cameras before. i had a bit of a google around and couldn't find a uk dealer. still, i should stick with my spc900 for now. i'm a raw beginner, and really need to save for a better mount (heq5 i think) rather than blow all my money on a camera i can't mount...

[Jupiterholic]

I captured approximately 18000 frames

:)

[Gadget]

That's a very nice early image cant wait to get a look myself i know Saturn has the wow factor but i don't think you can beat all that fine surface detail that you can see changing on Jupiter from hour to hour

Great stuff

Kevin

[Cosmin]

wow nice details, it looks great, haven't seen Jupiter in a long time...

[Space Cowboy]

.....much the same here Stuart: without checking, off the top of my head I'd say most probably around 25 degrees or so..!

I've just received a reply email from John Rogers of the BAA re my image remarking about the STZ's darkening apropos the GRS.

This apparition you folks in the Nthn. Hemisphere should be getting much better opportunities with Jupiter compared to previous years!

Will be a while before it hits 25 degrees here...another month I guess. As you say we will be spoiled this year when Jup hits the big 50 degrees!

[Kokatha man]

Will be a while before it hits 25 degrees here...another month I guess. As you say we will be spoiled this year when Jup hits the big 50 degrees!

I'll have to head North for anything above about 45 degrees or so Stuart.....fortunately Australia's a big country and cribbing 10, 15 or even 20 degrees isn't beyond achieving....!

ps: thanks Kevin and Cosmin..!

[King]

Nice to see an early Jupiter and what a result!

I tried going for it myself but the irony is that though it should be the easiest dawn planet to go for, it rises behind a higher building for me so I have to wait until it's over 15°. Thus far I've only managed to view it. Venus and Mars appear between buildings allowing me to capture them that much lower. Looking forward to after the summer solstice when the Sun starts getting up later again - though I suppose the opposite is the case in your region!

[Kokatha man]

Looking forward to after the summer solstice when the Sun starts getting up later again - though I suppose the opposite is the case in your region!

Thanks K.....yep, with the Sun rising later each morning and Jupiter rising earlier we're moving towards a situation where it should be readily imageable with reasonable expectations: it's up 3.5 hours before sunrise now, and unless the seeing looks like being good at home we normally go out to somewhere with flat North/Eastern horizons to maximise the possibilities.....it'll be under 50 degrees elevation here in Sth Oz this apparition, but as I said, we'll be willing to go 10 or even 20 degrees North to get the best out of the new scope when it finally arrives - and I get everything fully operational..!

[neil phillips]

Good to see Jupiter Return, its a nice shot, for the low elevation.

The SEB looks prominent. still too low here really. 14 degrees in strong light. might have a bash at some point though.

[Kokatha man]

Hi Neil - thanks! What we're seeing here on Jupiter now is not only the fully-revived Southern Equatorial Belt (SEB) but also the darkening and associated development of the Southern Tropical Belt/Zone (STZ/B) that the major part of the GRS sits within.....

It will be good to be able to image better when Jupiter gets higher in the sky - but now the boot's on the other foot so to speak, and you folks up North should begin to get some really opportune times....!