My first Saturn pic

[DannyHarvey]

After chasing Jupiter around for the past months, doing cycles reading and experimenting regarding capturing planets I finally feel I have made a big improvement with my first ever pic of Saturn (and the first ever time I have seen Saturn through a scope come to think of it!)

Here are the main things I have learnt over the past months:

1. Don't expect more than your scope can give - with that in mind I found out the max I can Barlow with my scopes resolution

2. Wait for some good seeing (Waited till Saturn was at its highest on a good calm clear night)

3. Get a good focus - used a Bartov mask ( not sure about the spelling!)

4. Ensure Collimation is good

5. Get to know your cameras software (using Neximage 5, use the Histogram feature to ensure gain setting is good, set to 15-20 frames sec, turn of the darned auto-white balance)

Now I just need to hone my Registax skills to get rid of that grain.....

Dan

[michael.h.f.wilkinson]

Very good first shot. Better than my first attempt. Colour looks pretty good too (perhaps a tad too much blue).

[DannyHarvey]

yes you are right, I had the gain on the blue channel a bit too high ( but not clipping). I should be able to fix it in photoshop right? (not sure how to yet)

[AstroAndy]

Nice pic., like the Cassini division.

[DannyHarvey]

Yes, I was so pleased I captured that! I was so exited when I saw it appearing out of the registax software!

[leelee970]

Very nice first image of Saturn, much better than my first attempt (although you could see the rings,lol). Well done.

[DannyHarvey]

to be fair, its not my first attempt at imaging per-se, I have been banging away at Jupiter for so long and I keep thinking, how can I make this better?

My efforts have paid off on this one I think.

Dan

[SnakeyJ]

Dan,

Very good indeed - nice banding, colour and ring detail. Obviously some grain/noise, which is going to be inevitable with this cam and cranking up the gain. I suspect more frames is the best answer, though current poor seeing I think this is a great result at this aperture and much nicer than I'm getting from my 8" newt. Out of interest how many frames did you capture/stack?

I've spent 6 pretty fruitless nights so far this month trying to improve on the first images I took of Saturn back in Feb. The seeing has been very poor, or it's been windy or I've got dewed up. I have the Bahtinov mask for my 200P, but never used - but I will give this a try. However, either the alignment will have to be spot on (so I can simply slew to Spica focus and back to Saturn), or I need to check stellarium for a good bright star (to focus the camera on) - preferably by only moving on one axis so I can easilly get back on target. My Baader CCD LRGB filters are supposed to be parfocal so I might get away with one focus - otherwise I will have to repeat this for each channel (LRGB).

The other big one (not on your list) is a more sensitive camera for higher frame rates - the firefly is giving me about 35 frames per second at 300x300 ROI and 24dB gain, Red drops to around 25 FPS, Green hovering around 20 and Blue 15 ish (perhaps with additional signal boost). These are all uncompressed SER video at 8bit and the peltier certainly helps to keep the noise down at these gain levels.

I believe the Neximage 5 supports 2 x 2 and 4 x 4 binning - so might be worth sacrificing resolution for higher sensitivity and frame rates - just a thought!

[DannyHarvey]

Jake,

The seeing wasn't great, but I could see for a few milli seconds here and there it was settling.

I captured about 1800 frames and stacked about 80%. I have more AVI's from the session (about 1500 frames each) that I haven't even looked at yet! I'm thinking of joining them all together to see if I can improve things (don't know how to d this yet!). The mask is great, but I have found you need to crank up the mag on the laptop screen to use it accurately - to see the three lines clearly. I get the image in the smallest fame, then crank the size of that frame to 150%. Upping the gain helps too.

I don't worry about accurate alignment for planetary, I get it close and I use the goto, but don't care if its a tad off, I just use the Telrad & a standard finderscope to get me on the objects accurately.

I don't want to use the Nextimages binning as this would mean I would need to add a Barlow. I have worked out the max resolution form my scope and related that to my pixel size an the Neximage complements that perfectly without the binning and without Barlowing.

regards

Dan

[SnakeyJ]

Very impressed that you are getting this image scale without barlow at all - time spent matching the components properly is certainly not wasted! This does alleviate the problem of finding the target again - I'm using x2.25 barlow in my 200P with the added extension of my filterwheel so probably around x3.25. At this magnigication finding the target is not so easy particularly with a bit of droop in the focuser (need to replace the holders with compression ring ones).

1440 frames is much higher than I'm doing - I'm generally stacking 400 of 1500 frames for each layer, as the seeing has been so poor. But on OSC you could get a much higher frame count - I believe PIPP will allow you to join multiple AVI files together, then perhaps sort more aggressively and stack.

You image is better than anything I've managed to get thus far, so I'm just thinking aloud while I wait for the next attempt Perhaps I'm trying to push the image scale too far given the prevailing conditions, but all part of the learning process.

[DannyHarvey]

Jake

With the Neximage I use 2592 x 1944 (max size at 6fps) when locating then switch to the 640 x 480 (up to 50 fps) for the actual capture.

I found this article very inspiring concerning using a small aperature scope:

www.project-nightflight.net/webcam_imaging.pdf

and this one for matching pixel size to focal length, specifically the equations on slide called sampling. (helps you decide if you need a Barlow)

www.alpo-astronomy.org/.../Owens%20-%20Planetary%20Imaging....

Dan