Dark Sky "First Light" with the Tele Vue-60is Imaging System

The following images were taken at the 2005 Eldorado Star Party, October 26-29, 2005 using a Hap Griffin-modified Canon 300D (no IR filter at all) on a Tele Vue-60is imaging system mounted on a Losmandy GM-8 mount and autoguided with an Atik IIhs webcam and GuideDog software.

Because the camera now has no infrared filter and none was used on the lens, wavelengths out to 1100 nanometers were recorded, creating a strong red collorcast. (At the time, UV/IR block filter for the TV-60is was on Santa's wish list. It was used for later images taken at the Texas Star Party in 2006)

These images were stacked and aligned using AIP4Win V2 and the excess red was removed using Photoshop 7.0. This is a less than ideal way to deal with the infrared contamination on each image, but until a UV/IR filter wa available, this is the best I could do. The color ballance on some images, such as M-31 and M-33, leaves much to be desired without an IR cut filter, but this is the way the camera sees them.

Complicating things at this year's Eldorado Star Party was the repeated appearance of thin high cirrus clouds. This compromised many images by bloating the bright stars to the point where the image was useless. Most of the images shown here suffered from this to some degree.

The primary goal of this first outing was to evaluate the astrohphotographic performance of the lens. In spite of the lack of proper filtration and the presence of cirrus clouds, this goal was achieved. In a word.. the TV-60is is outstanding. As can be seen, it records sharp, round star images to the edge of the field. While the lens is an f/6 system, it posseses sufficient speed and wide aperture (60 mm) to easily record faint nebula.

The images here look weasonably well focused, but in some cases the actually are not as well focused as they could be. The TV-60is is an incredibly sharp lens and thus requires very critical focusing...something I am still mastering. Thus some images are better focused than others even if they all look good, but then the cirrus clouds made a muck of of some of the well focused ones anyway.

Sharp-eyed viewers may notice that one side of the images (right edge on "landscape" perspective views) have slightly elongated stars. This, I believe, is a defect in the camera itself, not the TV-60is lens. This is caused by the CMOS sensor in the camera being slightly tilted to one side. This will be corrected in the future when the camera is altered to acheive proper infrared infinity focus when using standard camera lenses. The AIP4Win software has an interesting tool that measures star image elongation. It shows that stars along the edge of the field (except on the far right) are elongated no more than several hundreths their own diameter. Compared to my Nikon telephoto lenses, this is outstanding.

Although some of the images presented here are cropped, the targets are all displayed at the camera's full pixel resolution.

3072 X 2048 pixel 621 K .jpg The star group around Mirfak (Alpha Perseii). 6 min X 11 @ ISO 400

1635 X 2048 pixel 373 K .jpg NGC-1499, the California Nebula, in Perseus 6 min X 11 @ISO 400

3072 X 2048 pixel 710 K .jpg The star group around Delta Persei. OK, not the most inspiring astrophoto, but it demonstrates how easy it is to aim at the wrong star when you are really sleepy. I was really shooting for the Alpha Persei group shown at the top of the page. 6 min X 11 @ ISO 400

1638 X 2048 pixel 506 K .jpg Double Cluster in Perseus 6 min X 5 @ ISO 400

3072 X 2048 pixel 1,111 K .jpg The Butterfly Nebula, also known as the Gamma Cygnii nebula 6 min X 12 @ ISO 400

2048 X3072 pixel 572 K .jpg The Horsehead Nebula in Orion 6 min X 11 @ ISO 400

1914 X 2048 pixel 529 K .jpg IC 1805, the Valentine Nebula 2 min X 21 @ ISO 1600 This was an experiment trying shorter exposure at higher ISO in an attempt to control noise. It was less than successful, but the image isn't bad at all.

1162 X 1034 pixel 172 K .jpg M1, the Crab Nebula in Taurus 4 min X 11 @ ISO 400

1019 X 679 pixel 20 K .jpg M13 globular cluster in Hercules 1 min X 5 @ ISO 400

2250 X 1500 pixel 478 K .jpg M31, the Andromeda Galaxy 6 min X 15 @ ISO 400

1527 X 1014 pixel 123 K .jpg M33, the Pinwheel Galaxy in Triangulum 6 min X 11 @ ISO 400

2048 X 1352 pixel 334 K .jpg M34 star cluster in Perseus 3 min X 11 @ ISO 400

2038 X 1354 pixel 325 K .jpg M35 star cluster in Gemini 6 min X 10 @ ISO 400

2048 X 3072 pixel 500K .jpg M42, the Orion Nebula with a little "help" from cirrus clouds 1 min X 5, 2 min X 5, 6 min X 5 @ ISO 400

2316 X 1819 pixel 533 K .jpg M45, the Pleiades in Taurus 6 min X 11 @ ISO 400

2048 X 1436 pixel 504 K .jpg The star clusters M46 and M47 in Canis Major 6 min X 11 @ ISO 400

1947 X 1615 pixel 188 K .jpg The galaxies M81 and M82 in Ursa Major 6 min X 5 @ ISO 400

2042 X 1360 pixel 246 K .jpg NGC 1647 star cluster in Taurus 6 min X 6 @ ISO 400

1594 X 2043 pixel 509 K .jpg NGC 281, the Packman Nebula is Cassiopeia 6 min X 11 @ ISO 400

2048 X 3072 pixel 917 K .jpg The North America Nebula in Cygnus (through thin cirrus clouds) 6 min X 13 @ ISO 400

2038 X 1354 pixel 405 K .jpg TEastern portion of the Veil Nebula in Cygnus 6 min X 11 @ ISO 400

2042 X 1356 pixel 404K .jpg Western portion of the Veil Nebula in Cygnus 6 min X 11 @ ISO 400