Jupiter 03/11/12, 200p & SPC900

[SCOOB_81]

Evening All,

I’ve still got my 'L' plates on, but thought I’d post my best Jupiter to date. I’m really pleased with it as it was sort of proof of concept for me. I wanted to try stacking the standard SW 2x Barlow with my Tal 3x to produce a bigger image with the SPC900, process, and then reduce. I’ve seen people get some great results, and so I thought I’d give it a try.

I do struggle with the Bahtinov mask as the central spike always looks kind of warped with the SPC900. Has anyone seen this or have any suggestions, please? I think I’m always a fraction out of focus.

This was shot at around 2am, 03/11/12 with a Skywatcher 200p, EQ5 and motors. Video is 3 minutes (1800 frames) captured with WX AstroCapture, run through PIPP and stacked in Registax 6. I tweaked it a bit with my limited Photoshop experience and reduced to 50%.

Any advice is always appreciated!

Thanks!

Sean.

[budski]

Hi Sean, congratulations on a superb effort. Getting perfect focus is one of the hardest things to do because if the air above you is unsteady or polluted by water droplets/dust/smoke etc (especially around Fireworks Night) then nothing you can do will make things better. Another thing that will affect (blur) your images is the frame rate of your avi files. From your description you're running the camera at 10 frames per second (i.e. 1800 frames in 3 mins) which for planetary imaging is a tad slow. These days most of the commercial astrocameras can manage up to 60fps which would give your frame selection app a fighting chance to find the best (sharpest) frames to stack. The other thing to bear in mind with Jupiter, of course, is its rapid rotation which means that the features on the equator are moving at approx 45,000 kilometers per hour or 12 kilometers per second. Over a period of 3 minutes those features have moved approx 2200 kilometers - enough to blur their edges. The trick is to up the frame rate while reducing the time to about 60 seconds per avi. You can also employ an app called WinJupos to de-rotate the image. It all takes time and patience - but given the British weather it's a good enough reason to try these things out.

Regards

Bud

[StuW]

Good advice except that anything over 10fps with an SPC900 will introduce compression into the stream causing a loss of detail.

Fantastic image and far better than what I have been able to achieve with similar equipment.

Sent from my HTC One X using Tapatalk 2

[JamesF]

It's a good image.

With the SPC900 I'd stick to 10fps. At 640x480 resolution the SPC900 compresses all framerates except 5fps. Once you get beyond 10fps the compression is quite severe and you'll lose a lot of data. Unfortunately it has to be that way because the USB v1.1 standard doesn't have enough bus bandwidth to manage even 10fps 640x480 images without compression.

As regards capture times I wrote a piece based on my understanding of how things work here. The part about capture times starts about halfway down. I actually use a capture period longer than the theoretical maximum for my 127 Mak, at three minutes (1800 frames), but my plan for our next cloud-free night (about 2015 by the looks of it, and I'm not talking about quarter past eight in the evening is to try a range of capture times to see how well practice matches theory.

James

[budski]

Hi Sean, something I forgot to mention is that if you had looked at this section (planetary imaging)some two years ago the best we could hope for (on a good night of seeing) would have been images inferior to yours. With the advent of sensors like the Sony X618 CCD device, anyone with a half-decent 'scope can produce stunning pictures under the right conditions. Latest developments from companies like Point Grey and IDS are producing USB3 CMOS units which, in the fullness of time, will deliver results that'll make today's efforts seem tame.

On a recent UK exhibition I was shown a demo of an in-deveopment imaging chip which can 'see' in total darkness - at a price - 130,000 Euros. Naturally, I ordered 2 of them (haven't told the wife yet).

Joking aside, if you want to 'up' your game without crippling your domestic economy then look at the TIS DMK..618 range of cameras.

Cheers

Bud

[Space Cowboy]

Focus looks great to me Sean. You could increase frame rate to 30fps for focussing and then back to 10fps for capture as the faster rate does make it easier during focussing. The problem with a B-Mask is that the conditions constantly change i.e scope temperature, atmospherics and Planet position so ideally one needs to tweak focus every 10 mins sometimes more if seeing is variable so thats not easy with a mask.

A moon on view is great for focussing. Try keeping the capture histogram on astrocapture 60-70% maybe more for focussing on a moon.

Stick with 3 min captures. Yes in theory Jupiter does rotate during that time but stacking and aligning in AS!2 (Autostakkert) compensates up to a point. There is a image on here taken by Chris (cgarry) of Jupiter from a 10 min avi and rotational blur is minimal.

Winjupos de-rotation is a great tool for combining stacked images so you could combine 3 or 4 stacked avis into one image.

Your image has great detail!

[SCOOB_81]

Thanks for the positive comments and the information, gents. like I say, it's much appreciated.

It's a great page you've got going there, James. The image I've posted was actually a little comparison I was attempting myself. Like you with avi times, I was trying to compare the SPC900 to a modified Microsoft HD-3000. I was hoping that it might produce a decent final image with the frame rate being much higher at 30fps. The initial test wasn't so good as the image wobbles quite badly.

Bud mentions a dedicated camera, and I was interested in the imaging source type. If my budget stretched I'd like the camera and televue 5x power mate. Unfortunately, I can only get one. how do you choose between the chicken and the egg?? :-)

Thanks again!

Sean

[JamesF]

Useful idea to focus using a higher frame rate. I'd not considered that. I shall definitely try it next time we get a clear sky.

James

[JamesF]

It's a great page you've got going there, James. The image I've posted was actually a little comparison I was attempting myself. Like you with avi times, I was trying to compare the SPC900 to a modified Microsoft HD-3000. I was hoping that it might produce a decent final image with the frame rate being much higher at 30fps. The initial test wasn't so good as the image wobbles quite badly.

Bud mentions a dedicated camera, and I was interested in the imaging source type. If my budget stretched I'd like the camera and televue 5x power mate. Unfortunately, I can only get one. how do you choose between the chicken and the egg?? :-)

I have a modded Lifecam Studio that I really want to compare with the SPC900 too. Gary Honis seems to think that the Lifecams are potentially better than the SPCs, but my initial tests with Saturn earlier this year don't bear that out. I'm thinking that it may well depend on how bright the image is and potentially therefore be aperture-dependent. Given the lack of clear skies available for imaging though, I'm disinclined to spend time experimenting with a different camera when I know I could be capturing data with a camera that I know does a good job.

And on the subject of cameras vs. barlows, I'd almost certainly go for the dedicated camera first. The camera is something you could use no matter what telescope you had and is therefore fairly well future-proof. If you upgraded at some point in the future to an SCT or Mak for planetary imaging you'd probably find that a 5x barlow becomes largely redundant.

James

[SCOOB_81]

Again, great info folks, thanks!!

Haha, I'm in the same boat bud, where you play down the cost of your gear. My Mrs thinks my 200p was 250 pound brand new....... At least I'm thinking in the right direction with imaging source. They seem to be a popular choice!

I never considered upping the frame rate to focus either, will definitely try that next time. As James says though, that could be a while off just yet.

I've heard as2 and winjupos mentioned a lot lately. I'll have a good look while I'm stuck on this train.

Loads to think about, cheers!

Sean

[JamesF]

AS!2 is definitely worth having around. With high quality capture data my experience is that Registax v6 does ever so slightly better for me than AS!2, but it's not uncommon if the data is a bit variable for Registax to create all sorts of stacking artefacts including a sort of crazed look to the image. AS!2 will usually do the job properly when that happens.

(I'm quite happy to believe that AS!2 works better than Registax all the time for some people btw, but that's not my experience.)

James

[SCOOB_81]

That's a really great point, James. Should I keep the 200p for the next few years I might think again of the powermate, but a camera would seem to be the safest bet first.

Did you also find the image wobbled badly with the life cam? In moments of clarity the image looked really decent, but most were too bad to use in the final stack. I had the ms cam set on 640-480 to keep everything as comparable as possible. I'll keep at it, but I'm not convinced it's that great at the moment.

Cheers,

Sean

[JamesF]

I have to admit that I can't recall. Saturn was quite a difficult target with the Mak at that time and I wasn't very happy with the entire session really.

James

[budski]

Sean, I'm shocked! How could you deceive your good lady so .... ( by-the-way if you need any more plausible/deniable excuses - I have a whole book of 'em).

[Space Cowboy]

Sean is your scope f5 or f6? If its f6 then a 5x powermate will be a luxury rather than essential piece of kit as f30 is only usable in very good seeing. If your scope is f5 like mine then the powermate is a fantastic tool !

I've never used the a MS Lifecam and I've never seen any images online that match those taken with the spc900.

[bottletopburly]

excellent just bought some motors so can`t wait to try them out on my 200p and a celestron 2x well done

[JamesF]

I've never used the a MS Lifecam and I've never seen any images online that match those taken with the spc900.

I've never seen any either. Given a few decent days seeing I'd be very happy to spend some time giving the Lifecam workout in my Mak, but frankly when we're getting one clear night a month or fewer I'm really not inclined to spend it experimenting with the Lifecam when I know the SPC900 works well.

James

[StuW]

An alternative to the imaging source cameras is the ZW Optical ASI range. I've just ordered the ASI120MC colour which seems to have similar specifications to the DMK's but at a much lower price. Watch out for a review when it comes.

Sent from my HTC One X using Tapatalk 2

[JamesF]

There certainly appear to be a few decent images taken with that camera, so I look forward to the review. Are you importing the camera from overseas, or do they have a UK reseller now?

James

[StuW]

Unfortunately the only UK dealer (speedflameout) isn't answering emails, messages on here or any other form of communication, so I contacted Sam directly. You can buy them on his aliexpress site for import. The one I got worked out around £175 with free delivery thanks to the good USD exchange atm.

Sent from my HTC One X using Tapatalk 2

[JamesF]

Even if you get stung for the VAT on top of that it still compares well with the price of a DFK, certainly.

James

[SCOOB_81]

Hi All,

I'm just back in the country and so I wanted to say thanks again for the info!

My scope is an F5 version, and I was very tempted by the Powermate while I was away. As luck would have it (and bizarrely), the car insurance was really cheap this year and so used the money to order a 5x Powermate from Green witch, which came the next day (Cheers Lee!). I didn't even need any of Bud's creativity in explaining myself to the Mrs, as the Powermate was also on special.

I've been looking up those ASI cameras you mention, StuW. They look really canny. Any news on delivery yet??

Oh, and just a bit of info for Bottletopburly. I also upgraded to motors on my 200p (it's fantastic!), but had issues with my first hand set. The set wouldn't light up correctly and the motors barely moved at all, despite checking voltages, trying batteries, different power packs and the likes. In frustration I upped the voltage too far and fried the controller. Unfortunately, in doing so I'd also fried my evidence to a defect, and so had to fork out again for a replacement. I'm sure you wont make the same mistake, but just passing on my experience!

Thanks again,

Sean.

[sologuitarist61]

Not sure what all the fuss is about Sean I think it is an image that most would be proud of