Posts Made By: Roland Christen

Hi Astro-Geeks

Astro-Physics has designed and now tested a new accessory for wide field imaging with the 130 GT refractor. The new Telecompressor-Corrector operates at 600mm (approx. F4.6), and will cover a 4 degree field with extremely sharp performance from deep red to the far violet. All the individual color images of R,G,B and L will come to the same focus with the same small star sizes.

The compressor is a 4 element design using a high performance ED glass mated with high index Lanthanum crown. This combination preserves the high color correction of the 130GT lens all the way across the spectrum. On a reasonably stable night the star resolution in a 10 minute exposure will be on the order of 1.1 to 1.3 pixels FWHM with the 5.4 micron 8300 chip - for all 3 colors and Luminance.

The attached image shows the field size of the 8300 chip (QSI 683WSG). The 5.4 micron pixel size is ideal for this focal ratio, producing 1.8 arc sec per pixel. This is an LRGB of M13 with 4 x 5 minute exposures. I am somewhat limited here at my observatory test site, right in the middle of a very light polluted suburban shopping district, so I am not able to show any ground breaking images from here. These images are simply to show the potential of this accessory.

The scope that was used is our newest incarnation of the 130GT, now designated as the 130GTX. It sports a 3.5" focuser with Feathertouch fine focus and a new quick attachment system.

Rolando

The full image is at 50% of full resolution.

Hi Astro-Geeks

Astro-Physics has designed and now tested a new accessory for wide field imaging with the 130 GT refractor. The new Telecompressor-Corrector operates at 600mm (approx. F4.6), and will cover a 4 degree field with extremely sharp performance from deep red to the far violet. All the individual color images of R,G,B and L will come to the same focus with the same small star sizes.

The compressor is a 4 element design using a high performance ED glass mated with high index Lanthanum crown. This combination preserves the high color correction of the 130GT lens all the way across the spectrum. On a reasonably stable night the star resolution in a 10 minute exposure will be on the order of 1.1 to 1.3 pixels FWHM with the 5.4 micron 8300 chip - for all 3 colors and Luminance.

The attached image shows the field size of the 8300 chip (QSI 683WSG). The 5.4 micron pixel size is ideal for this focal ratio, producing 1.8 arc sec per pixel. This is an LRGB of M13 with 4 x 5 minute exposures. I am somewhat limited here at my observatory test site, right in the middle of a very light polluted suburban shopping district, so I am not able to show any ground breaking images from here. These images are simply to show the potential of this accessory.

The scope that was used is our newest incarnation of the 130GT, now designated as the 130GTX. It sports a 3.5" focuser with Feathertouch fine focus and a new quick attachment system.

Rolando

The full image is at 50% of full resolution.

Dark clouds gathering over our prairie restoration site next to the Astro-Physics factory. The Baptesia plant is a wild Illinois native species that flowers in early to late spring. Also known as Wild False Indigo.

Rolando

This image was taken last night with the TEC 140 scope + Quad TCC, under so-so seeing with high thin clouds running thru my exposures. Sorry about the poor quality, but it shows the field size of this combination. Image at 730mm focal length, F5.2, 18x300 sec Luminance, 1x300 sec RGB. Image half sized (half resolution)

Rolando

A very faint but interesting nebulous region in Cygnus. Shot with the TEC140 and AP Quad TCC at F5.1, 8x15min H-a exposure.

There is more interesting stuff all around, so I will visit this area again and try a mosaic of the region. It is all very faint, buried in bright stars that overwhelm the picture. A very narrow H-a filter is needed, perhaps a 3nm, to suppress the stars. In my case I was working with a 5nm filter, which did not reject the stars as much as I wanted, so I had to resort to other measures of star filtering.

Rolando

Same night I took an image of M51 with the TEC 140 at F5.1. Total exposure 2 hours Luminance. This is a crop, upsized by 1.6x to show detail in the galaxy.

Rolando

I finally had another so-so night where I could see a few stars, so I was able to test the system with the 35mm chip of the STL11K. The weather here has been terrible with lots of cloud cover and haze from fires up north in Canada. During one 3 hour period I was able to get some testing done of the 130 GTX and Quad TCC attached to the STL11K camera, all mounted on a Mach1 mount.


Here is the result of only 3 x 15 minute exposures of the H-alpha clouds in Cygnus:


http://www.buytelescopes.com/content/images/thumbs/0066461_hydrogen-alpha-region-in-cygnus.jpeg


If I can get a few clear nights I plan to shoot a 9 panel mosaic of this entire region.


Rolando

I finally had another so-so night where I could see a few stars, so I was able to test the system with the 35mm chip of the STL11K. The weather here has been terrible with lots of cloud cover and haze from fires up north in Canada. During one 3 hour period I was able to get some testing done of the 130 GTX and Quad TCC attached to the STL11K camera, all mounted on a Mach1 mount.


Here is the result of only 3 x 15 minute exposures of the H-alpha clouds in Cygnus:


http://www.buytelescopes.com/content/images/thumbs/0066461_hydrogen-alpha-region-in-cygnus.jpeg


If I can get a few clear nights I plan to shoot a 9 panel mosaic of this entire region.


Rolando

This is a 4 panel mosaic of star clouds and H-alpha regions in Cygnus.

Roland

This is a 6 panel mosaic starting from the crescent nebula going south. Each panel consists of a number of 15 minute exposures, number depending on how clear the skies stayed during each imaging session (anywhere from 4 to 14 subs). There is a lot of stuff there. Have fun identifying it all. I will post a larger version in the Gallery.

I used the 130EDX with Quad TCC running at F4.6, STL11K CCD camera, guided on the Mach1 mounting.

Rolando