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Jupiter, 10th/11th Jan and ASI120MC first light

JamesF

By JamesF
in Imaging - Planetary

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JamesF

JamesF

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Four weeks I've had to wait to be able to try my new camera out. Really bored of the rubbish weather now :(

We finally got a break in a month of cloud last night after a day of rain. The atmosphere seemed quite clear, but exceptionally unsteady. Just to make sure it wasn't too easy, the wind was gusting from the north east as well. Even stars at the zenith were twinkling rapidly. I couldn't let the moment pass though, so I got the 127 Mak set up and did a first run with the SPC900 just to get my eye in:

spc900.png

The seeing was so unsteady that I initially thought I'd somehow managed to get some dust on the sensor despite having it completely sealed all of the time. It took some time for me to realise it was a transit shadow. Focusing was a nightmare thanks to the combination of the wind and the image of the planet jumping all over the sensor.

After completing a dozen or so runs with the SPC I swapped to the ASI120MC and from SharpCap to FireCapture (might as well make the learning curve as steep as I can :) Because of the smaller pixel size of the camera I also removed the 40mm extension I usually put behind my 2.5x barlow. Just as well I did, as the mirror shift when refocusing takes the image completely off the 640x480 section of the ASI sensor that FireCapture was showing me :( Nothing much I can do about that unfortunately. Perhaps when I have the lathe properly set up I might attempt to make a more accurately machined mirror carriage for the Mak.

I'd familiarised myself with the FireCapture controls, but still had a fair bit of learning to do and as the frame rate went up (I stopped at 30fps) it just showed up how unsteady the atmosphere really was. These are some of my first few attempts. Mostly picked at random because none were exactly outstanding. No idea where the boxes have come from either:

asi120mc.png

I don't think it's really a fair test of the camera in such poor conditions, but even so I think they're clearly an improvement on the SPC900 and for the moment I must be happy with that.

James

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Cozzy

Cozzy

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James given the appalling weather conditions lately and bubbling atmosphere I think both cameras have done a great job, but like you say it's difficult to a compare in these conditions. congrats on the break in the clouds, we still have the norm which is cloud and rain, hey um.

Tim

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Virgoman

Virgoman

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I think you have made a great start James despite all conspiring against. The seeing is such a lottery but there is plenty of detail there including a transit shadow - something I have yet to acquire this apparition. Congratulations on the new camera it looks good and hope to see plenty more images.

Best regards,

Ralph

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StuW

StuW

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Nice first light!.. I've not had a chance to try Firecapture myself yet, but I like some of the added options like focus help etc. Hopefully Sam can add the Ascom stuff to the driver in the next update.

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Space Cowboy

Space Cowboy

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Nicely captured images James! I'm sure after some practice your new cam will show even more improvement over the spc. You can see how much sharper and less distorted the transit shadow is on the ASI shots probably due to the faster frame rate beating the poor seeing.

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JamesF

JamesF

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Thank you for the comments, all.

I think I need to do a couple of things now. First is to work out how to display the full image from the camera in FireCapture (by default it offers me 640x480) so I can focus without worrying about the target shooting off out of view. I don't want to capture at that size, but for focusing it would really help. If I can do that then I might even put the 40mm extension back in for a larger image. I was only using 50% gain for these, so if I have to push that up a little it's hardly the end of the world.

The other is to try higher frame rates. At some point I think lack of aperture is going to get me. Really need to get the obsy set up soon. Not in this rain though :(

James

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budski

budski

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Hi James, just confirm that this is the OSC 120MC camera you're using as Darryl refers to it as the 'MM' in his reply.

What's your impression regarding focusing the live image with the smaller pixels?

Looking forward to seeing more results from your camera ... If this cloud ever lifts.

Bud

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StuW

StuW

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What's your impression regarding focusing the live image with the smaller pixels?

I don't know about James, but I found focusing quite easy with the high frame rates, the motorized focuser helps a fair bit though.

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JamesF

JamesF

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Looking very promising. These cameras seem to be excellent value for money. Possibly more aperture will even better exploit its abilities, so you need to get the big scope setup. Jupiter is getting smaller by the day now :-(

It is, but it's not going anywhere in the long term. And if I get things set up I might have a go at imaging it during the day...

James

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JamesF

JamesF

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Hi James, just confirm that this is the OSC 120MC camera you're using as Darryl refers to it as the 'MM' in his reply.

What's your impression regarding focusing the live image with the smaller pixels?

Looking forward to seeing more results from your camera ... If this cloud ever lifts.

These images are using the colour MC version, yes.

Focusing didn't seem too hard. The worst part is coping with the mirror shift when the focuser changes direction.

James

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Kokatha man

Kokatha man

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Sorry if I confused anyone Bud - "MC" I should've said!

Torsten sent Sam and me the latest "Build #37" the day before yesty where it's no longer necessary to go into the .ini file to change from "true to "false" for the colour camera.....but there's a couple of little glitches that still need fixing for it to be running completely smoothly with this new version.

You don't go into the .ini file to alter the resolution however - that is up on the LHS of FireCapture just above the image screen where you type/select the "1280x960" in the box and then hit the little arrow up there to convert to that particular resolution.....doing the same for the other resolution you wish to change to will enable that etc, etc...

Just make sure that you centre the planet on the screen before you change to the actual resolution you wish to use - paying particular attention to the scrollbars in your centring process otherwise the planet might not be "on chip" when you change resolutions..!

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budski

budski

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Hi James, yes that mirror shift business is the reason why I went for the bolt-on MoonLite Crayford focuser and locked-down the mirror. I'm also fast coming to the conclusion that unless we get some steady clear weather, the OSC route looks to be a more viable option if one wants to have a half-decent result to show for a night's work.

I met up with Pete (Theo) from North Somerset at the SGL event at Taunton Race Course last Thursday and have to say that his printed and framed Jupiters taken with the colour DMK.618 looked superb.

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JamesF

JamesF

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I didn't even realise there was an SGL event at the race course! Who organised it?

Sometimes there's a strong temptation to get an external focuser, but we are only talking about a 127 Mak and it does seem a bit overkill. Perhaps if one comes up second hand at a reasonable price...

James

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budski

budski

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Hi James, the SGL event was organised by BBC TV & Radio Bristol. Quite a few local astro groups attended as well as the Exmoor National Park people. There were a number of other attendees -Daleks and Cybermen ... so it was a truly intergalactic event! Try as hard as I did, I could not get the Dalek to loan me his 36 quintillion pixel camera with the see-thru-cloud facility....

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theo

theo

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Hi James,

This event was organised by the BBC and a few of the local astronomy groups along with Exmoor National Park help to run the event.

It was very successful I feel even though the not surprising rain / cloud cover was there in abundance!!

It was also great to meet Bud at the event. What a nice chap he is. Many thanks to him for the comments on my Jupiter pictures :-)

Regards,

Pete

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