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2010-11-10 Spectral Image Focusing Spectra Filter Test for Zero Order Shift Images from 2010-11-10 >> 2010-11-15 Spectral Image Focusing Update
Spectral Focus Profile, measured over
a 20 pixel wide window covering part of the first order spectrum (Star Analyser 100) |
Realtime observatory graph Filter : Star Analyser 100 filter / Star : a star in Vulpecula 2010-11-10 18:04 to 18:08h (profile S435-3) 12" LX200R (at f/9.7) + ST-10XME + Optec TCF-S |
Comparison between first order and
zero order focus A difference of 215 steps is noted between the best focus positions (note : first and zero order measurements made on same image) |
Excel Graph Filter : Star Analyser 100 filter / Star : a star in Vulpecula 2010-11-10 18:04 to 18:08h (profile S435-3) 12" LX200R (at f/9.7) + ST-10XME + Optec TCF-S |
Representative Image at best first order focus |
Annotated CCD Spectral Image Star : HIP 98375 (F0) in Vulpecula 5s exposure (single frame), 1x1 binning, S Filter 2010-11-10 18:06h (Snap.1805.49.focus_2883) 12" LX200R (at f/9.7) + ST-10XME |
Representative Image at best zero order focus |
Annotated CCD Spectral Image 5s exposure (single frame), 1x1 binning, S Filter 2010-11-10 18:07h (Snap.1806.55.focus_3093) 12" LX200R (at f/9.7) + ST-10XME |
Update - 2010-11-15 Instead of focusing over a vertical column centred around the middle width position (as shown above) a new facility has been added on 2010-11-15 whereby a rectangular area is draw over the first order spectrum in order to set up a precise focus window . |
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Spectra Filter Test for Zero Order
Shift Back to back images of HIP 98375 taken through C Filter and Star Analyser 100 were taken and a blink comparison made (animation captured below). The test confirms that the zero order images taken through Star Analyser 100 is for practical purposes exactly coincident with star position taken through normal filter, showing that there is no image shifting. This is important confirmation as it makes it easier to design automated autoguiding routines |
Animated CCD Images (cropped / no
alignment of images) a) 3s exposure (single frame), 3x3 binning, C Filter b) 3s exposure (single frame), 3x3 binning, S Filter 2010-11-10 17:46h (429179) 12" LX200R (at f/9.7) + ST-10XME |
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Focusing Update - 2010-11-15 Instead of focusing over a vertical column centred around the middle width position (as shown above) a new facility has been added on 2010-11-15 whereby user can draw a rectangular area over the required section of first order spectrum in order to set up a more precise focus window . |
Screen Capture of a realtime observatory
image 1s exposure, 1x1 binning, S Filter, 2010-11-15 |
Spectral Focus Profile, measured over
rectangular focus window covering first order spectrum (Star Analyser 100) |
Realtime observatory graph Filter : Star Analyser 100 filter / Star : HIP 117718 in Pegasus 2010-11-15 20:06 to 20:09 (profile S437-3) 12" LX200R (at f/9.7) + ST-10XME + Optec TCF-S |
Representative Image at best first order focus |
CCD Spectral Image Star : HIP 117718 (M2iii) in Pegasus 1s exposure (single frame), 1x1 binning, S Filter 2010-11-15 20:08h (Snap.2008.05.focus_2594) 12" LX200R (at f/9.7) + ST-10XME |
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This Web Page: | Notes - Session 435 (2010-11-10) |
Last Updated : | 2015-05-15 |
Site Owner : | David Richards |
Home Page : | David's Astronomy Web Site |