What problem on the emulsion

[LT_Ng]

Hi Folks,

The attached image was taken through 8" F4.5 Newtonian + TV parracorr + Vixen VX-1 camera body + E200 slide, and the exposure time was 15 minutes, manually guiding with Vixen GP-DX mount + Vixen 70S(7cm F420mm) guiding scope + 2x barlow + Pentax IR-E6 guiding eyepiece. 1 stop push in developping.

The location where I shot this image was very severely light polluted but the transparency of that night was quite good. So, I could see mag. 4 stars very easily.

What ideal with the problems on the emulsion before/after developping, other than vignetting, tracking error?

Thanks for your opinion.

Clear skies,

LT

[westsky]

Hi Lt, nice image, what it really needs is to be taken at a darker location.
15mins on E200 slide is considered a long exposure 30 mins on this film and it tends to saturate the image, this film is very light sensitive particually with any reds as you can see in your shot.
I think you will get similar results with any film in light polluted sky, I think that maybe 5mins would be a maximum exposure time and then you have the problem of not getting enough light onto the film to see the object, so the simple answer is go out into the country and get some darker sky.
E200 can be pushed two stops in processing, it is a great astro film it picks up red very easy and is good on blues but it fails somewhat on green's and yellow's.

cheers
David.

[LT_Ng]

Hi David,

Thanks for your input.

E200 is really very sensitive to red colour (H alpha) in comparison with other same speed emulsion but I don't think the problem was caused by the one you are suspected. Because the whole strip is red colour tinted slightly. That means the unexposed strip shows red colour tinted and a little transparent also, which should be black and opaque to weak light for normal strip. Moreover, it was unbelievable that the strip after developping was contracted by a little than normal!
By the way, any one is welcome to have a trial on processing this "reddish" image to dig out data as more as possible, and if possible, it is appreciating that you would give us a brief description for sharing purpose on which routine of processing and what software you apply.

Clear skies,

LT

[asimov]

Hi there. I had a bit of a play with your photo. Done in my software that came with my scanner 'micrografx picture publisher 8' Tone balance + hue map + pure saturation shift.

Could not get the natural colours of the stars because I know virtually nothing about this sort of thing.

[Kieken]

I did some processing to. I substracted the funky color in PS and turned the picture in greyscale. I also played around with contrast and brightness.

http://users.pandora.be/willy.geys3/Astronomie/Dubbele%20cluster.jpg

Perhaps send me or upload the full resolution? Would be a nice practice to. :)

[gbeal]

Not something wrong with the film itself perhaps, as the unexposed portion should ideally be clear as you say.
Maybe fogged before/during/after exposure, or during processing. Old film perhaps?
Perhaps not stored correctly?
I have never really been a fan of push processing.
Film? What is this?
Apart from the vignetting, and obvious fogging, it is a nice image.

[acropolite]

Fogged by Airport xray machine perhaps.