Some Saturn and Jupiter

iceman (Mike) · #1 02-02-2005, 03:45 PM

Hi guys.

Here's a couple of Saturn and Jupiter images I took on Saturday night (30/01/2005) and Monday night (01/02/2005).

I think I had the saturation a bit low for the Saturday night, but otherwise they turned out ok. Focus looks a bit sharper, probably thanks to the moonlite.

Seeing was pretty good on Saturday, a bit worse on Monday.

I don't know, maybe i'm reaching the limit of what I can produce with a non-tracking dob. I've seen others take their first avi's of Saturn (like Gordon) with a tracking mount and produce better results than me, when i've been doing it for a couple of months..

My results are slowly improving, but unless I get perfect seeing I can't see my planetary images getting much better than they currently are. I'm guessing that there must be a slight blurring effect due to the speed the planet drifts through the FOV.

For the jupiter images, the right-hand side images and the large one have Europa just off the right-hand-side of the disc.

Comments and suggestions welcome, if you can suggest something i'm doing wrong or should do differently, either in capture or processing, in order to get the nice sharp images that others are getting, that'd be great.

(the number next to the planet is the number of frames stacked)

Saturn 29/01/2005

Saturn 01/02/2005

Jupiter 01/02/2005

Thanks for looking.

ving (David) · #2 02-02-2005, 04:09 PM

there is only so much you can do with a dob mike. you orta be congratulated with what you have done.

westsky · #3 02-02-2005, 04:50 PM

Hi Mike I second what Ving said, Your Jupiter shots are better than any of my Jupiter shots to date and thats with a tracking mount. so well done.

David

gbeal · #4 02-02-2005, 05:19 PM

Sorry mate,
time to make the scope track, no other way around it. Not necessarily a GEM, a tracking platform will suffice, as will an alt/az (servocat type) arrangement.
Good work though, and the patience of a saint.
Gary

Starkler (Geoff) · #5 02-02-2005, 06:10 PM

Mike how good is the seeing at your place?
If its as rotten as it normally is in Melbourne, your behind the 8 ball from the word go.

If you can get yourself near the ocean the seeing is often much better.

Robby · #6 02-02-2005, 07:07 PM

Nice shots Mike,
I've always found the 600 frames is about right. Anymore and you don't gain very much, but it may also depend on seeing, aperture etc...

[1ponders] (Paul) · #7 02-02-2005, 07:15 PM

Mike I'd like to see a list of your settings that you are using for capture. And what settings you're using for processing. I'm assuming that you are capturing in K3ccdtools and processing in Registax, would that be right?

Jupiter looks slightly out of focus, if thats so, then that would certainly be affecting how much detail you can bring out. How many times do you need to move your dob to do consecutive avies. What I'm thinking is, if you focus on jupiter at the start, everytime you raise your altitude then the atmosphere is getting thinner. Changing the refactive characteristic of the atmosphere, and changing your overall focal length. If you assume the astmosphere is a lense. Others who have tracking can make longer avies, though in shorter time than you,without having to focus. This may be because the change in Atm thickness is less over the shorter time. IMHO anyway

What does this all mean? Time to get tracking

Same thing with Saturn only more of a problem with lower altitude. How low is saturn in altitude there?

What does this mean? Time to move further north to get better seeing

(when the clouds clear)

I guess that means moving to queensland, say on the sunshine coast, and getting a Losmandy mounted 5" Tak (G-11 of course).

You could probably be able to find someone to give you a hand to set it up.

Seriously though Mike, are you using a Hartman or focusing aid? How low is Saturn, and what settings? Maybe we can eliminate something and help you get shots you're really happy with.

Still say it though. Class of your own.

Good ones

iceman (Mike) · #8 03-02-2005, 09:32 AM

Quote:

Mike how good is the seeing at your place?
If its as rotten as it normally is in Melbourne, your behind the 8 ball from the word go.

If you can get yourself near the ocean the seeing is often much better.

I don't know what else to compare it to, it's good sometimes, not so good at others. There's definite shimmering of the image in the avi but i've imaged in worse.

Quote:

Mike I'd like to see a list of your settings that you are using for capture. And what settings you're using for processing. I'm assuming that you are capturing in K3ccdtools and processing in Registax, would that be right?

Yep, that's right.
For capture, I use 90%ish saturation, for saturn I use 1/25s shutter, jupiter was 1/50s. Gain was high enough to see the detail, I experimented with gamma on these shots and had them higher than normal, about 30% (normal I set gamma to 0).

For processing (in registax) I usually do an auto RGB shift, set the step mode to 2 to adjust wavelets 1, 2 and 3 (to about 9-12), or I set the step mode to 0 and adjust layers 3, 4, 5 and 6 (3 highest, around 30, going down to 6 at the lowest, around 3 or 5). Just trial and error.

Quote:

What I'm thinking is, if you focus on jupiter at the start, everytime you raise your altitude then the atmosphere is getting thinner

It's possible, but I don't think so. The planet goes through the FOV in about 12 seconds at 2500mm focal length (that's with my 2x barlow). I start capture when it enters, and stop capture just before it exits. I then use the finder to realign, and do it all over again. I'm getting better at it, so there's sometimes only 20 seconds (or less) BETWEEN captures.

Because Jupiter's feature rotate in about 90 seconds, I usually only use 3 or 4 of those 12 second avi's when stacking a Jupiter.

Saturn was about 33degrees alt.

Quote:

Seriously though Mike, are you using a Hartman or focusing aid?

I used a hartman mask and focused on a star first, but as with the planet, I need to achieve focus while the star drifts through the FOV in 12 seconds, so it's hard to get it just right. The fine control on the moonlite helps but I need to make a triangle mask like yours to help me see the diffraction spikes better.

Thanks for your feedback everyone, it's frustrating but my images are improving, so it's still worth persisting for now

I need a EQ platform!

[1ponders] (Paul) · #9 03-02-2005, 04:43 PM

FWIW for Saturn, I set my saturation a bit lower to around 65 - 80 %, gamma 0, if I thnk I need a RGB shift its usually only red and blue maybe 1 point, for me red down 1 and blue up 1. Adjust only wavelets 1 & 2 normally (sometimes 3, but not often) step mode to 0. 1 normally around 20 - 25 and 2 up to about 12 max and 3 if necessary just a touch, maybe up to 3-5.

Mike do you have any of your lenses, say a 15 mm parfocal with your ToUcam? If not this might be something to consider. It would give you a wider FOV in which to get your focus worked out and not be so rushed in the process.

BTW, what time of the night are you doing your imaging at the moment and how much movement is there in your mount when your focusing? Oh and what were the wind conditions on the nights? I know you'll have that written down in your log like me.