Hi, The attached image of the veil has some field curvature on all edges and an interesting focusing where the right side of the image is not as focused as the left. Is this a camera plane alignment problem? I'm using the SBIG STX11002 mono w/self guiding filter wheel on a Televue NP127IS scope. I want to know what you think. Is there something wrong with the camera or the matchup or what? Also it has a Moonlight 2.8inch motorfocuser. The camera is mounted with a threaded adapter to the focuser so the outside alignment can't be moved. I don't know about the internal alignment. Note the image was reduced in size to be uploaded so it may be hard to see. -Mike
Hi Michael, See 4.1 in the manual. You can adjust the tilt there on the 127is. Have you tried adjusting the tilt? http://www.televue.com/pdf/literature/Tele Vue-NP127is Operating Guide_1256.pdf 4.1 Adjustable Position End Ring The tilt of the End Ring to the optical axis can be changed to compensate for any tilt errors you may see in your photography. The telescope is aligned with the End Ring locked firmly against the end of the draw tube. In this way you are always assured of a reference point to return to if necessary. To determine which way to tilt the End Ring, it is necessary to focus on the part of the image that comes to focus first when racking out the focuser from its “in” position. That will permit adjusting, or “jacking,” the End Ring “out” to match that focus point in the field. You will need to remove your camera equipment, including the Imaging System Adapter to adjust the tilt of the End Ring . Slightly loosen the three Jamb Screws located on the face of the End Ring with the appropriate Allen key. Then, “jack” the End Ring to the desired position using the appropriate Allen key Jack Screws. Tighten the Jamb Screws against the End Ring and reinstall your camera. Some trial and error imaging will be necessary, so it is best to carry out any necessary adjustment during an imaging session. You can also shim the camera/filter wheel as well if needed. http://www.sbig.com/site/assets/files/1416/stxl_filterwheel_manual_022613.pdf See page 3: Remove the 3" adapter ring from the camera front cover being careful to note the location of any shims used to assure orthogonal camera position and attach this adapter plate to the front cover of the filter wheel replacing the shims, if any, in the same locations.
Hi Tim, Thanks for all the information, that should correct the focusing issue. Will that also correct the coma I have, the picture I sent was downsized so it doesn't show up on the same image I sent. In addition the field curvature the stars are round in the center of image but the corners they looked like there trailing. As this picture does not show the full effects you can see the trailing as described above. Thanks again Mike Sent from my iPhone On Dec 14, 2015, at 10:36, Diffraction Limited - SBIG / Cyanogen Forum <noreply@cyanogen.com> wrote: Diffraction Limited - SBIG / Cyanogen Forum Michael chiarella, Tim Puckett replied to a thread you are watching at Diffraction Limited - SBIG / Cyanogen Forum. Field curvature Hi Michael, See 4.1 in the manual. You can adjust the tilt there on the 127is. Have you tried adjusting the tilt? http://www.televue.com/pdf/literature/Tele Vue-NP127is Operating Guide_1256.pdf 4.1 Adjustable Position End Ring The tilt of the End Ring to the optical axis can be changed to compensate for any tilt errors you may see in your photography. The telescope is aligned with the End Ring locked firmly against the end of the draw tube. In this way you are always assured of a reference point to return to if necessary. To determine which way to tilt the End Ring, it is necessary to focus on the part of the image that comes to focus first when racking out the focuser from its “in” position. That will permit adjusting, or “jacking,” the End Ring “out” to match that focus point in the field. You will need to remove your camera equipment, including the Imaging System Adapter to adjust the tilt of the End Ring . Slightly loosen the three Jamb Screws located on the face of the End Ring with the appropriate Allen key. Then, “jack” the End Ring to the desired position using the appropriate Allen key Jack Screws. Tighten the Jamb Screws against the End Ring and reinstall your camera. Some trial and error imaging will be necessary, so it is best to carry out any necessary adjustment during an imaging session. You can also shim the camera/filter wheel as well if needed. http://www.sbig.com/site/assets/files/1416/stxl_filterwheel_manual_022613.pdf See page 3: Remove the 3" adapter ring from the camera front cover being careful to note the location of any shims used to assure orthogonal camera position and attach this adapter plate to the front cover of the filter wheel replacing the shims, if any, in the same locations. View attachment 1288
Hi Tim, Thanks for all the information, that should correct the focusing issue. Will that also correct the coma I have, the picture I sent was downsized so it doesn't show up on the same image I sent. In addition the field curvature the stars are round in the center of image but the corners they looked like there trailing. As this picture does not show the full effects you can see the trailing as described above. Thanks again Mike Sent from my iPhone On Dec 14, 2015, at 10:36, Diffraction Limited - SBIG / Cyanogen Forum <noreply@cyanogen.com> wrote: Diffraction Limited - SBIG / Cyanogen Forum Michael chiarella, Tim Puckett replied to a thread you are watching at Diffraction Limited - SBIG / Cyanogen Forum. Field curvature Hi Michael, See 4.1 in the manual. You can adjust the tilt there on the 127is. Have you tried adjusting the tilt? http://www.televue.com/pdf/literature/Tele Vue-NP127is Operating Guide_1256.pdf 4.1 Adjustable Position End Ring The tilt of the End Ring to the optical axis can be changed to compensate for any tilt errors you may see in your photography. The telescope is aligned with the End Ring locked firmly against the end of the draw tube. In this way you are always assured of a reference point to return to if necessary. To determine which way to tilt the End Ring, it is necessary to focus on the part of the image that comes to focus first when racking out the focuser from its “in” position. That will permit adjusting, or “jacking,” the End Ring “out” to match that focus point in the field. You will need to remove your camera equipment, including the Imaging System Adapter to adjust the tilt of the End Ring . Slightly loosen the three Jamb Screws located on the face of the End Ring with the appropriate Allen key. Then, “jack” the End Ring to the desired position using the appropriate Allen key Jack Screws. Tighten the Jamb Screws against the End Ring and reinstall your camera. Some trial and error imaging will be necessary, so it is best to carry out any necessary adjustment during an imaging session. You can also shim the camera/filter wheel as well if needed. http://www.sbig.com/site/assets/files/1416/stxl_filterwheel_manual_022613.pdf See page 3: Remove the 3" adapter ring from the camera front cover being careful to note the location of any shims used to assure orthogonal camera position and attach this adapter plate to the front cover of the filter wheel replacing the shims, if any, in the same locations. View attachment 1288
Hi Tim, Thanks for the information on adjusting the tilt, I did not know that. The picture I attached was downsized and does show the coma and the star trailing at the field corners. Will this also be corrected from the tilt adjustment?? Mike
Thanks for calling. You will need the Televue LCL-1069 Large Field Corrector • Optimizes edge of field performance. Recommended for 35mm CCDs (43mm diagonal) and larger. Again glad you called, we can cover a lot more ground over the phone. Cheers Tim
