RGB widefield from Crago - Pentax 200mm

[multiweb]

Here's one I've just finished processing. Approx 40x2min with my 200mm F4 lens one stop down. A lot of star bloat so I'm getting a step down ring to fit a UV/IR filter or some kind of Nebula filter to stop that. It was a pain to process in the blues and greens as a result. Red was tight enough.

Here's one big one here (http://www.astropic.net/astro/NGC6188b_ff.jpg)[4MB] . The field is approx 8x8 degrees.

Looking forward to do some more from Ilford this week-end. :)
I've just received my new 100mm F2.8 lens and it has a 49mm pentax UV/IR cut in the front :cool:

[Ross G]

Great shot Marc.


Sharp and so much detail.

The lens gives you an excellent FOV.

See you in Wiruna.


Thanks.


Ross.

[Hagar]

Very nice Marc. May take a while to settle in to this wide a field when processing it but it looks good so far. Stars don't look to bad.
A lot of wide field imagers seem to bloat up the brighter stars and blur them a bit to lift the image and give it some punch.
Nice and sharp without blurring the background.

Well done.

[multiweb]

Thanks Ross - see you there. :thumbsup: BTW I got a 50mm F/1.7 and 28mm F/2.8 too. :)



Thanks Doug. :thumbsup: Definitely a different way of processing. Getting around it now. Another thing to learn but it's fun. And easy to capture.

[jjjnettie]

Wide Field rules!!
It's nice for a change isn't it. Low stress imaging. :D

[Dennis]

Wow Marc- you don’t hang around do you, already putting the Pentax 200mm F4 to work! That is a very nice shot – the 4 Meg image is an absolute ripper!

Cheers

Dennis

[desler]

I quite agree with everyone Marc. Nice, very nice! and the learning curve continues!


Darren

[Ross G]

Wow Marc!

A 50mm and a 28mm. There is no stopping you now.

You've got all FOVs covered. You are going to need a 2nd and maybe 3rd camera!

The quality (...and quantity..) of your work will be amazing. I am looking forward to it.

I have been experimenting this week with the 50mm lens. I am finding I like it even more then the 135mm.

Good luck.


Ross.

[gbeal]

Again with the #8 wire technology, I used to tape a 1.25" IR/UV filter into the rear of the Pentax 55/4 (67 lens) I used, the rear opening and element were close to the 1.25" size, and the IR/UV cleaned up the bloat a bit.
Gary

[multiweb]

Thanks JJJ. :thumbsup: Sure is. :lol: Nothing else to do with the seeing of late.


Thanks a lot Dennis. Glad you like dit. :thumbsup: This is a bit new to me and I wasn't sure about posting it.


Thanks for the kind words Darren. :thumbsup:


No camera for me for a while. My next one will be definitely a mono.


Thanks Gary. I was wondering if star bloat was caused by internal reflections or just focusing different wavelength in different locations like chromatic aberration. That's why I thought I'd but the filters before the wole lens assembly.

In NB I did put the Ha/Sii/Oiii filters at the back with no issues at all. No internal reflections and no star bloat which goes inline with what you're saying. Here's 3 channels on the same area I did earlier still to blend. It looks very different in RGB though that's why I went to a dark site to test. I hope to get a lot of data this week-end and test further.

[strongmanmike]

Looks ok Marc.

Have you posted that combined SIIHaOIII on 6188 already, I can't remember? It looks good too.

Mike

[multiweb]

Thanks mate. Nah... I haven't processed it yet. Still collecting data and I was trying to get RGB stars before combining but that last outing at Crago didn't go to well. I ran out of power at 22:00 [low voltage] and spent the night looking up at a blazing, still, milkyway. :sadeyes: Hopefuly I bag a load from Wiruna. Living tomorrow morning.

[Paul Haese]

Looks very good Marc. I like the dark dust knots and the hints of hydrogen surrounding these areas.

[multiweb]

Thanks Paul. :thumbsup: The plan is to go deeper once I have those stars under control. 200mm is the sweet spot I reckon for that kind of imaging. Nice FOV and image scale.

[Tom Davis]

Nice one! There is lots of stiff in that frame!!

Tom

[ving]

nice... whats it a widefield of?

[multiweb]

Thanks for that Tom. :thumbsup:



Thanks David. :thumbsup: It's NGC6188 at 2o'clock from the center. At the bottom left you start seeing the nebulosity associated with the prawn nebula IC4628. With the 100mm I should bridge the gap between those two and frame them nicely. Still experimenting a lot. The only thing I don't have to worry about is guiding. :lol: .. which is refreshing. ;)

[gregbradley]

That looks good Marc. Are these Pentax 67 lenses or some other format?

Good tip about the UV/IR cut filter. I have a Pentax 55 F4 so I'll do that.

This is the perfect time of year to be doing lens widefield shots.

Greg.

[multiweb]

Thanks mate. Yeah the milkyway's right up. Can't miss it ;)

The lenses are M prime series: SMC Pentax-M.
I now have 200mm F4, 100mm F1.7, 50mm F2 in the post and biding on a 28mm F2.8.

The 200mm has a great flat field even fully open. Haven't tried the 100mm yet. They're all use a K-mount and similar so I can use them exactly the same way with my QHY8 adaptor.