Posts Made By: Don McCrady

Here's my capture of this nice apulse of Venus with the Pleiades cluster. I shot this from my back yard using my Tak Sky 90 and Canon Digital Rebel. This is a single exposure of 15 seconds at ISO 800.

Thanks.

Here's the result of tonight's session, under a quarter moon and moderate light pollution. My polar alignment was not perfect, so the stars are slightly oval shaped, and my focus was off a little bit. (Speaking of focus, my attept to do this same image last night was ruined because all my images were out of focus. Apparently I forgot to tighten the focus lock after shooting my focusing test image. Wah.) Oh, and you might notice a satellite trail which went through one of the images.

Anyway, I combined 16 3-minute images at ISO 800. This image is shrunk 50% in a blatant attempt to hide the above-said errors.

http://dandkmccrady.home.comcast.net/images/M101-2004-04-25-50pct.jpg

I'm understandably proud of this one, it's my best yet. This image was taken under quite severe moonlight with my Takahashi Sky 90 and CanonDigital Rebel at f/4.5, mounted on its Losmandy GM-8 equatorial. It is 16 exposures, two minutes each, at ISO 800. Calibrated, aligned, and combined in Images Plus. Gradient removal in Photoshop. Digital Development and Lucy-Richardson deconvolution in Images Plus.

Comments welcome. Thanks.

This is comet C/2001 Q4 (NEAT) taken with my Digital Rebel attached to a Takahashi Sky 90, mounted on a Losmandy GM-8. It is 32 exposures of 1 minute each at ISO 800. The comet moved significantly during the sequence, so the background stars are trailed.

Thanks.

Here is Hickson 68, one of the better galaxy clusters up there. It was taken with my Canon Digital Rebel through a Takahashi Sky 90, mounted on a Losmandy GM-8. It is 26 exposures of 2 minutes each at ISO 1600.

Thanks.

This image needs more signal, but the appearance of clouds killed off some of my exposures. I had programmed a sequence of 32 images of 2.5 minutes each (ISO 1600), but clouds rolled in and I only got 8 usable images, totalling only 40 minutes of exposure time. This was also taken in my back yard under moderate light pollution.

Two new things this time around helped out a lot.

1. I finally figured out Images Plus's focus evaluation (FWHM measurement), which really helped me focus by the numbers. I wouldn't say my focus is perfect, but it's very close. I daresay I wouldn't get any closer without Tak's new 10-1 fine focuser (which is on backorder for me as we speak).

2. I also used Images Plus in concert with a custom parallel port shutter release cable to enable my computer to handle the entire imaging sequence. It works great.

This image is reduced 33%.
Most processing was done in Images Plus, with colour balance, and a final screen layer to brighten up the nebula in Photoshop.

Comments always welcome. The image is available at the following link:

http://dandkmccrady.home.comcast.net/images/NA-2004-05-24.jpg

Here is my first attempt at M31 from the night of June 20th. This was shot from my LP backyard at 2:30AM with my Takahashi Sky 90 and Canon Digital Rebel at f/4.5, mounted on a Losmandy GM-8, unguided. Unfortunately, my camera battery died before I could complete my planned set of 32 exposures, but I did get 23 exposures of 2.5 minutes each, for almost an hour total exposure.

The raw images suffered from some very complex gradients. To remove them satisfactorily, I split the image into separate R, G, and B components, and processed them separately (background compensation, digital development) using Images Plus. I combined the three channels back into a colour image for another set of processing (edge subtraction to shape the stars a bit, and a bit of colour re-balancing).

I'm still not totally happy with the colour... a bit too much green and a bit too much purple, but it's close.

The full-res version is available at http://dandkmccrady.home.comcast.net/images/M31-2004-06-20.jpg

Comments always welcome.

Here's my latest M27. I shot the original exposures back in May, and then an additional set on June 19th. Since the red sensitivity of the Rebel is so poor, I used the red information from the June exposures, and added into the red information of the May exposures.

Red = 32 x 2.5minute exposures at ISO 1600, plus 32 x 3 minute exposures at ISO 800.
Blue = 32 x 2.5minute exposures at ISO 1600
Green = 32 x 2.5minute exposures at ISO 1600

Combined and processed in Images Plus.

Thanks.

I shot the following image after doing some PEC training runs on my GM-8... I still need to average in more training sessions because I only got 8 shots out of 25 without trailing.

I combined these using sigma-clipped median (and had to discard a good frame due to a satellite trail). A little DDP and just a touch of Richardson-Lucy deconvolution was all I did. The colours came out much better than you can see in this crappy JPG, but I'm doing my bit to preserve bandwidth.

Comments welcome... thanks.

I know this wasn't an ideal target with the moon as bright as it was last night. However, I've been training the PEC on my GM-8, and wanted to go deeper on a target than I've ever done before. I think I have the PEC trained pretty good now because my test exposures showed that I could get reasonably round stars with a 4 minute exposure (5 minutes wasn't too bad, but the elongation was noticeable).

So here's a portion of IC 1396 in Cepheus, known as the Elephant's Trunk Nebula.



I tried various combine methods in Images Plus, but Adaptive Add produced the smoothest result. Unfortunately, adaptive add caused excessive brightening, clipping some of the colours. I fixed this by using Photoshop to subtract out a constant bias from each image before doing the Adaptive Add.

I did some smoothing, then sharpening in Images Plus, and some final tweaks in Photoshop.

Comments welcome.

Thanks.