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NGC4216 with supernova 2024gy

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Posts Made By: Daniel Reyna

May 14, 2002 05:47 PM Forum: Film Astrophotography - Imaging and Processing

Gamma Cygni region

Posted By Daniel Reyna

Single 40 min shot on Fuji Super HQ 100 through a Megrez 80 at f/5. Processed in Photoshop 5.


June 4, 2002 02:58 AM Forum: Film Astrophotography - Imaging and Processing

N.A. Rework

Posted By Daniel Reyna

Looks much better, much more even, and I like the color! Looking at the histogram there is still some room for contrast improvement. The image is somewhat flat and there is a lot of dead space in the histogram that should be filled up. Reset the dark point a bit dark to bring the shadow end of the histogram as far left as possible without clipping it. This should increase the contrast of the nebulosity.


July 11, 2002 04:20 PM Forum: Film Astrophotography - Imaging and Processing

Color and Film Question

Posted By Daniel Reyna

This could be either a difference in the films' response, the printing/processing, or both. Planetary nebula are among the hardest because of the "OII gap." Most films seem to have low response to the OIII line and this is where a great deal of energy is emitted by planetary nebulas. This will throw the color off a great deal. A bad scan will also do this.

No real comparison can be made unless the background color of the two photos matches. To really compare the two you should reset the dark point of the original scans using the same color and using the same spot. Compare the colors, any difference will probably be due to spectral response.

July 17, 2002 01:26 AM Forum: Film Astrophotography - Imaging and Processing

Slides or Film?

Posted By Daniel Reyna

Slide film is typically more expensive than negative film and costs around $7-$9 to process. Kodak E200 seems to be the best by for pretty much everything, I've had great success with it, while Fuji Provia and Velvia seem to do very well of blue objects like comets.

The problem with slide film is that it has less dynamic range than negative film causing brighter stars to have burned out cores and less extended detail in faint objects. While fancy processing techniques can fix this, it isn't as good as negative film. Also, you will normally have to push slide film to get nice density unless you have exposures greater than 40-50 min at f/5-6.

As for negative film Fuji 800 in my opinion is less than ideal. When I shot it a year ago it had little red response and the color balance was very poor. Reciprocity was also quite bad. I've been using Fuji Super HQ 100 lately and have been very happy with it. It's red response could be better but it seems to have almost no reciprocity. The grain is very fine for color film and has great dynamic range. It's also very cheap, you can get a 4 pack for about $7. Kodak has discontinued all of it's good films (PPF PJM and PJ400) but hypered Royal Gold 200 is turning out great stuff lately.

My advice, pick a few different types and use a roll of each on similar objects then compare them to see what you get.


July 26, 2002 01:43 AM Forum: Film Astrophotography - Imaging and Processing

My Rho

Posted By Daniel Reyna

That's a fantastic wide-filed shot of that area. A little processing will do this one wonders.


November 28, 2002 05:51 AM Forum: Film Astrophotography - Imaging and Processing

M42 and horsehead

Posted By Daniel Reyna

Well here is mine, a single 45min shot at 400mm, f/5 on E200. I don't know how light polluted your site is but just a few minutes is the minimum in my opinion to get faint nebulosity. In you shot I can see the Flame Nebula just faintly. Keep bracketing the shots and see what come out.


January 16, 2003 06:06 AM Forum: CCD Imaging and Processing/Solar System

m81 again...reprocessed...

Posted By Daniel Reyna

Nice, very nice. Good detail in the dust lanes and outer regions of the core. The color seems a bit blue to me and the background looks clipped. Lighten up the background to try to bring out more faint detail but that might not bring out much if it is clipped severely. Give it a try one the originals to see what comes up.


April 14, 2003 08:46 AM Forum: CCD Imaging and Processing/Solar System

Help w/ ST4

Posted By Daniel Reyna

The numbers displayed by the ST-4 show the value and the location of the brightest pixel, even if the brightest pixel would barely show up on an image. Regular, random noise is common and actually expected especially if you haven't taken any dark frames. It is most likely causing the numbers you're seeing, I see them every time I power my ST-4 up. The "all zeroes" method means nothing to me. The only time I ever got all zeroes was when my battery was nearly dead. In my opinion if you didn't take a dark frame and the values are all zeroes there is a problem.

Read the article Don posted a link to. It is a fantastic one especially since the user manual is just about worthless. I've read the thing many, many times and the article is what made learning the ST-4 so easy for me.

When you power the unit up immediately push interrupt. The camera will cool down by itself and shouldn't need monitoring. I would hardly call it a "process" as well. I can, and have, power it up and begin tracking within just a few minutes. The ST-4 seems intimidating but it is actually very easy to use once you get use to the simple interface. I've had great success with my ST-4. My first really long-exposure photos were taken after the second time I had even touched one.

The biggest piece of advice about the ST-4:

"When in doubt, take a dark frame."


May 20, 2003 05:13 PM Forum: Star Parties

RTMC - weather looks decent...

Posted By Daniel Reyna

Can't wait! I hope the weather is nice and foggy down in the LA Basin. Next year should be snowy, if the 8-year cycle keep up.


July 10, 2003 02:51 AM Forum: Film Astrophotography - Imaging and Processing

Photographic Magnitude Limits

Posted By Daniel Reyna

I imaged Markarian's Chain last April with my Borg 100ED. After registering screen shots from Guide 7.0 to the image I was able to locate PGC 169437 in my image. Guide gives the magnitude of this galaxy at 18.8. I also have located other galaxies in the low 18's and high 17's. I don't know how accurate the magnitude data is for the PGC catalog but that might give you an idea as to how faint one can get on film.