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First H-alpha Photo

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#1 AstroMan0

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Posted 18 November 2012 - 09:41 PM

Well, here is my first attempt at photography with a filter (#29 deep red filter). It did its job quite well, as I was able to go almost 45 minutes on Gamma Cygni with almost no fog. Excuse the star trails- I was guiding when a skunk came out of nowhere and startled the heck out of me, causing the scope to move! I put the guidestar back where it was, and exposed a little longer before i decided to stop. Also excuse my lousy post-processing efforts- I got tired of trying to deal with 25 mb read-only files. Oh well- I'm better in the darkroom than with Photoshop anyways.

Clear skies,
Noah

Film: Hypered Tech Pan, hypered 72 hrs
Filter: Lumicon Wratten 29
Lens: 152mm f5.9 Achromat
Guiding: Manual with OAG and Illuminated Reticle
Mount: Losmandy G11
Scan: 9600 dpi of original negative

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#2 Michal1

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Posted 19 November 2012 - 03:40 PM

Hi Noah! How are things going with focusing? It seems they do pretty well. How does the frame look on the film? I'd expect hypered TP can capture more nebulosity in such an exposure. Have you tried to make a daylight photo with that film? Maybe it wasn't stored correctly. I'd also try Fujicolor C200 to see what you can do with an ordinary unhypered film. It is a cheap and H-alpha sensitive film. Hypered TP must record nebulosity much better than C200. Keep experimenting, your scope evidently has good potential.

#3 AstroMan0

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Posted 19 November 2012 - 03:58 PM

Hi Michal,
Things are going okay with focusing. I am thinking of parfocalizing my illuminated reticle and focusing through that. As for the film, I think it may have recorded more nebula, but I really have no idea how to post process. After I scanned the negatives at my grandmother's house, I tried playing with them in Photoshop a little, but I had to stop and finish at home. When I tried to edit them, they were read-only, and The only way I could edit it was to use the snipping tool and save it as a new file. This produced very low resolution compared to the original, though. I think the film is okay. It was sold on Ebay with a guarantee, and the seller posted a scan of a negative he took of a daylisht scene, and it looked fine. It expired in 2000, but it was frozen, and since Tech Pan is so slow,it expires very slow anyways. A possibility could be that I didn't hyper long enough, or at a high enough temperature (I'm still working on getting the temperature up). Another possibility may be that the filter blocked so much light that I needed to expose longer to produce the same density on the film as an unfiltered exposure.

Thanks and clear skies,
Noah

#4 Michal1

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Posted 19 November 2012 - 05:29 PM

According to this table
http://www.karmalimb...ratten filte...
(page 3), the #29 filter transmits almost 90% light at 656 nm. A photo must be judged from the negative itself, which we can't see here. The objects, which can't be seen by eye on the film, are hard to visualize by post processing and the use of a high quality scanner may be needed. I can't help you with hypering, because I have no experience with it. If you find the problem in your film, there is the successor of TP, the Rollei ATP. As far as I know, nobody has tried it for astro work so far, though. I also recommend to plan the shot in advance. Cartes du Ciel is good for it or an older photo can serve as well.

#5 AstroMan0

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Posted 19 November 2012 - 08:23 PM

Hi Michal,
I just checked the negative, and at least to my eyes it appears to have higher resolution and contrast than the scan (my darkroom prints are also a little better quality),though it is still blurred (darn skunk!). I still don't think it's the film (it better not be for what I paid for it!). Trying that Rollei ATP sounds like a good idea. Eventually, I'll probably experiment with hypering times, development, etc. First, I'll focus on getting some really good photos with Tech Pan, perfecting darkroom techniques, etc., and then maybe I'll move into uncharted waters!

Noah






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