I had a suprise clear night on Saturday, and being in-between on my set-up between an NP-101 and C-11, I only had my web camera available.

I have also just bought a 4x Televue Powermate that I wanted to try out. Thankfully the seeing turned to be ok. Saturn was the obvious target.

The shot is 604 frames of about 1,800, stacked in Registax. I used the diadic rather than the linear wavelet sharpening in Registax. When I moved to Photoshop, I increased the bit resolution by 4x so I had more granularity to work with when sharpening with a high-pass filter and slight blurring to soften the grain.

As always, comments and suggestions are welcomed.

As I went through the process of posting my older astrophotos, I came across this image of NGC 7331, a spiral galaxy in Pegasus.

After posting the image, I decided to take a stab at processing it again. Not from scratch, but from the reduced (flats and darks applied, blooms removed) versions of the original 9 images. I loaded them into CCDStack, aligned and combined the images, then pulled the final image into Photoshop. Applying the techniques I have learned in the last year, I got a much nicer image.

It is interesting how much difference processing technique can make on an image. The CCDStack and Photoshop techniques I used were:

• Used the build in digitial development in CCDStack, and combined using sum
• The first save with CCDStack I saved the top image. Don’t do this. It saves a smaller image than the underlying data. Use Save Data > This > 16 bit TIFF > Scaled while you have the combined image selected.
• In Photoshop, blur the base image using dust and scratches paste that back on top of the original image with a blending mode of difference
• Apply a reveal all layer mask and then mask the galaxy. These two steps eliminated the light pollution gradient.
• Copied the base layer, applied a 8-pixel high pass filter, set blending to soft light, applied a hide all layer mask, and revealed the galaxy detail. This sharpened the details of the galaxy.
• Added a curves adjustment layer and brightened the image a bit.

I am looking forward to updating some of my other old images.

I finally had the combination of clear skies and not being out of town for work. No matter that the moon was almost full. I have put my C-11 back on the CGE and am planning to do some f10 imaging (in the spirit of Yoda, I am not saying that I will “try” f10 imaging).

However, with Saturn transiting around 9pm this was a good opportunity to try some planetary imaging.

The seeing was not great. I tried a couple sets of shots at f20 and f30 using a Philips ToUCam Pro. At f30, I had to have the gain very high so the image was grainy. I also think that the seeing was not good enough for F30.

Both images are around 200 frames of 1700 or so frames taked with the webcam and stacked with Registax. For both images, I created a 50-frame stack and re-optimized with that enhanced stack (this is a standard Registax feature). I stacked to about 90-92% quality. I tried going for higher quality percentage, but at 95% I only had 50 frames and the end image was too grainy.

Direct links are: f30 image and f20 image

Comments welcomed!

The standard for amateur astrophotography is really quite high. I do OK, but I feel the pressure to not undertake any project if I can’t get 3-5 hours of exposure time.

I think that doing OK is OK — I just need to keep reminding myself of that.

Interesting information from a Slacker Astronomy podcast.

At the recent AAS meeting, someone presented a method of calculating the expansion of the universe using gamma ray bursts. This technique allowed the expansion to be calculated farther back in the past than the current supernova method. The preliminary results showed that the expansion due to dark energy has not been constant over time, that is the cosmological constant isn’t constant.

The presenter, Brad Schaeffer, was very clear that the results were preliminary and interesting, but not final. He also emphasized that what he was presenting was a new technique that could help answer the cosmological constant question.

According to the podcast, another researcher whose primary work is in supernova analyses of cosmological expansion, openly told people in the press that this result and technique were meaningless and wrong. It came over that he was rejecting something without adequate analysis, with the implication he was doing so because his funding for supernova research might be challenged. Go figure.