Advise with imaging

[Budgie]

Well, the New Purchase Cloud finally cleared last night and was able to spend a couple of hour observing with the Nexstar 127 SLT.

In the process I tried out the Neximage cam to see what it was like and to test the Registax software.

Attached is Jupiter with two moons but as you can see there is no details on the planet at all. I could see the red band clearly with my 25mm EP.

I found it hard to get any type of focus, even using a home made Bahtinov (which works fine) and there was a lot of "noise" in the image on the PC. I managed to reduce the noise using the camera controls but that made no difference to the detail.

The camera has an IR block filter on it and was used without anything else, just put into the diagonal.

I've read about increasing the frame rate to improve resolution, being the first time out I didn't play with this, I just used what came up on the software. Would this reduce what looks like burnout of the image and improve detail?

Any advice, hints & tips gratefully received.

Edit: I've just checked the AMcap settings and it is set to 30f/s, which is the max for this software so it can't go any higher.

Also, I took 400 frames for stacking.

[riklaunim]

You need to lower exposure time to no-overexpose the planet. To get moons you need what you have done - longer exposure with overexposed planet and visible moons - then you cut the moons to norma exposed planet image

NexImage is similar to a webcem - on higher frame rates it will start to use compression for frames which isn't nice.

[Budgie]

So take a couple of stacks, one as I have it now to get the moons and another with a lower frame rate for the planet.

The Exposure was on auto and un-checking that, revealed it was set with the shutter speed at 1/50 sec and gain was as low as it can go (assuming zero is on the left of the slider).

One thing I find annoying, and didn't notice until I'd looked at the files this morning, is that you have to specify a different file name for each capture, otherwise it overlays on what you've already captured instead of continuing from where you last stopped the capture or time stamping a new file.

Still, it's all a learning process and I'm not taking it too seriously at the moment.

[ezza123]

Martin,

Did you get this working in the end??

I am debating what to do about a webcam, for the 127 MAK either modify one or pay full whack for a neximage.

Does the neximage go right in to the scope or can you put it on the eye pieces?

Aaron

[Helen]

You put the neximage in instead of an eyepiece.

Helen

[ezza123]

That is where I get confused! How can you get such good images from the web cam directly in to the scope?

I tried Saturn with my Eos 500 last night with Mirror lock-up enabled, using a 32mm eyepiece with t -ring adapter x2 Barlow.

When I blew the images up they were very blurred and had no detail, Surely it should project the image closer than using a web cam directly in to the telescope?

I know the cam has a smaller sensor, but how does that make it better to produce better images, the SLR's larger sensor, so would still capture the same amount of light wouldn't it?

I assume I am missing something here as I am totally novice at this.

[riklaunim]

The bigger the planet image is - the fainter it get and needs longer exposures which are affected by seeing in greater degree than smaller scale images taken with shorter exposures

- You have to have good focus when imaging

- You have to set shortest exposures times at which you get good iluminated frames

- You need to capture a lot of frames

- And then you have to stack them into one final image and process it with wavelets, sharpening/convolution etc.

[ezza123]

Thank you riklaunim, I have lots of reading to do then!

[Budgie]

Martin,

Did you get this working in the end??

I am debating what to do about a webcam, for the 127 MAK either modify one or pay full whack for a neximage.

Does the neximage go right in to the scope or can you put it on the eye pieces?

Aaron

Hi Aaron,

I've not had chance to try it again as it's need cloudy and today the wind's blowing at 60mph + up here, so I'm not too hopeful for tonight either.

The Nexcam works fine without an EP, I used it with a solar filter on the 127 SLT pointing at the Sun spot a couple of days ago and was seeing just the area around the Sun spot itself. With my 400D attached to the scope and wihtout EP or diag' then the Sun filled the image area. So there is a good magnification with the Neximage.

I looked at doing a webcam mod vs Neximage but by the time you've got a good webcam + EP attachment & done the conversion, you were only about £20 short of the price of the Neximage. So I went for the easy route.

I know my problem is the operator and not the equipment, I just need time to play with all the settings to see what effect each has on the final image. I've found some settings on here that another 127 Mak used tried on Jupiter, so I've got those noted and will try them when this storm passes and I get some clear sky.

[riklaunim]

Try at day - focus on some trees (but not close to sun) and make an AVI like it was a planet It won't move so you can easily check settings and other options.

[Budgie]

Trees? We don't have any trees.

Got a house or two I can focus on but that seems to work fine during the day, it's getting the right exposure & frame rate for night obs that needs playing with.

I'll maybe try a distant streetlight or two this evening.

Thanks for the help & info BTW, it's much appreciated.

[Helen]

You might find this helpful Planetary imaging with a toucam Its MartinB's tutorial on using a toucam for planetary.

Helen