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Sunday, June 28, 2009

Monsoon Season is upon us...

Well, so much for stargazing...can at least enjoy the evening light show when the storms roll through. In the meantime, I will be preparing for the next outing. A new TI-89 programmable calculator is on order, and this one includes a real-time clock for more accurate shutter control timing. This will consume a little extra time to revise my ASTROTMR TI-BASIC program with improved settings.

A short focuser extension tube and a Lumicon broadband filter are also on order. The short extension tube should permit me to put the diagonal back in, now that I'm committed to using the field flattener in my astrophotography. The broadband filter will help reduce the additional sky glow, especially when imaging more toward that part of the sky with the Tucson "light dome."

Since I've made progress using the field flattener and corrected my process to create darks and bias frames, thinking about going all the way and experimenting again with 12,800 ASA! I've already taken 100 bias frames set at that speed. Will plan on taking 100 darks at this extreme when the next clear night arrives and maybe shoot for the Lagoon Nebula, again. Pretty exciting stuff!

Monday, June 22, 2009

47 Messier objects and counting...

...only 62 to go.

Messier 21

Yep, I think I've definitely hit the sweet spot with this new camera and RCT configuration. The field flattener delivers. The open cluster M21 here, 180 x 15 sec. JPEG frames, 3200 ASA, Astro-Tech Field Flattener, calibrated with 100 bias and 100 darks.

Messier 19

The globular cluster M19 here, 180 x 15 sec. JPEG frames, 3200 ASA, Astro-Tech Field Flattener, calibrated with 100 bias and 100 darks. Note, additional noise reduction not enabled, standard DSLR picture settings.

Vignetting resolved!

Introducing the new 2" field flattener from Astronomy Technologies. Designed originally for use with refractors, it appears to work extremely well with a Ritchey-Chretien telescope, too. Last night I used it in taking both M19 and M21, and I am very pleased with the results! The impact on the uneven distribution of light (vignetting) across the image has been dramatically reduced, to the point any negligible artifacts are easily stretched away.

Unfortunately, I lose my forever focus as it requires I remove the diagonal and add a 2" extension. I'll see about ordering a 1" extension and putting the diagonal back - the diagonal makes for a more comfortable viewing position of the camera LCD image display.

Thursday, June 18, 2009

M11 and M18

Seized upon a great dark night and grabbed these two shots of Messier objects 11 and 18, both open clusters. Messier 11 is known as the Wild Duck Cluster. I understand the bright stars appear to form a triangle like a flight of geese, don't see it.

Worked on my image processing some, and in these shots all additional noise reduction on the Rebel T1i was turned off. Camera brightness, contrast, sharpness, and saturation levels were all in standard settings. As such, I took 100 darks and 100 bias frames to perform image calibration during post-processing. This time I did bias correctly by setting camera to the shortest shutter speed, 1/4000. No flats this time, that's for another blog entry.

The following picture of M11 comprises 180 x 15 sec. JPEG frames at 3200 ASA, calibrated with 100 bias frames. Stacked and stretched.

This lovely shot of M18 is 1800 x 15 sec. JPEG frames at 3200 ASA, calibrated with 100 bias and 100 dark frames.

Wednesday, June 3, 2009

M22 and M57

Here are the last two shots taken in May, the lovely M22 (one of the largest globular clusters in our galaxy) and a retake of M57. The last time, M57 was taken I used a 2x Barlow lens and, of course, it magnified all my fine errors. Interesting that this time using an f/9 telescope, the 15 megapixel DSLR can capture M57 at the same equivalent magnification and resolution as was with the Barlow on the 6" f/5 Newt. Well, I guess that makes sense, f/5 x 2 = f/10. Both these images were unguided, 180 x 15 sec JPEG frames, 3200 ASA, with noise reduction enabled.

See ya' in a couple more weeks.

Monday, June 1, 2009

Wrapping up...

This dark period is almost over, and the night is wonderfully clear. Here are a couple photos of the new gear in action! Alignment was spot on tonight, tracking extremely well. I have to admit, using the calculated transit for Polaris really makes unguided work painless. Was really waiting for the Moon to go down so I could get one last shot in, M22. So, while we were waiting I went ahead and took 180 frames of M57, the Ring Nebula. Should be interesting to see if the baffling makes any difference in the moonlight.