HA Sun, 31st May 2013, TAL 100/PST mod

[lukebl]

Hi all,

Here's my first effort with my newly-modded PST/TAL 100, with the extension tube removed to allow focus without a barlow. Boy, it's hard work getting a decent image and this is the best of a bad lot. Any idea how I can reduce the horrendous vignetting which you can see in the dark area in the centre of the image? Is it possible to take flats with this type of imaging to get rid of it?

IMG132e cam, TAL 100RS/PST, c. 1000 frames stacked in Registax 5

[lukebl]

Here's a couple of edits, where I've manually had a go at reducing the vignetting. Still got a lot to learn here!

[allcart]

Hey thats not bad Luke. Is the camera mono or colour?

It needs a bit of colour correction, the green turned down and remove the blue if you haven't done it already.

If you have photoshop you could adjust the levels on a layer, then add a layer mask and use a circular gradient tool to mask out the changes from the centre and just reveal the outside. It might take a few tries to balance it out but it may help.

The proms look really good.

[lukebl]

Cheers Allan. The camera is a colour one, but I processed it in mono in Registax, and then played around with the colour balance in Photoshop. I would have preferred to use my QHY5 mono cam, but you just can't get short enough exposures with it without getting banding artifacts once you go faster than about 1/100 sec. Must learn about doing layer masks...

[allcart]

Well I take my hat off to you anyway. You managed to get surface detail and excellent proms in one shot. I usually have to do 2 seperate exposures.

[lukebl]

.... I usually have to do 2 seperate exposures.

It WAS 2 separate exposures!

[allcart]

Damn it !! I only have one hat. Well I'll put it back on again. Well blended Luke.

[lukebl]

Thanks for the advice Allan. I've changed the colour balance, and I think it works better. Looks a bit like a Jaffa Orange, though.

[allcart]

Still better than an Edam cheese.

[JamesF]

It's an excellent image. Seems like there's plenty of learning to do once you get into Ha solar imaging. I have a plan, but I'm not quite there with it yet.

James

[DrRobin]

That is very good Luke. You have got some really good detail in there. You can do a flat in one two ways, either centre the sun ad defocus or just put a diffuser on the front. I use tracings per, but others have used a Tesco bag to AC as a diffuser. Both methods increase the exposure time, but give a fairly good flat.

Robin

[michael.h.f.wilkinson]

Nice shots Luke!

[lukebl]

Cheers guys.

However, I'm not convinced that the expense of this PST mod has really been worth it! I'm a bit underwhelmed with the results, compared with the basic PST.

[Zakalwe]

Awesome images!

This might be of help:

http://www.schursastrophotography.com/solar/Articles/solararticle5.html