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Paramount
2013-Aug-14, 09:33 AM
Veil Nebula in HST palette (First light with prototype Tele Vue NP127/FLI imaging system)
A few months ago David Nagler from Tele Vue and Greg Terrance from FLI spoke to me about a very interesting collaboration between them to produce a complete imaging system i.e. telescope (a specially designed and customised spacer tube in place of the stock mechanical focuser), an accurate and stable electronic focuser, filter wheel and camera. David asked me if I would like to beta test the system for them over the next few months, well, I jumped at the chance.
The system consists of an NP127is tube assembly and in David’s own words

“We have taken our NP127is tube assembly and fitted a properly dimensioned, solid spacer tube in place of the standard focuser body. The length of the spacer tube is designed to put the FLI Atlas focuser at the centre of its travel. Incorporated into this tube is a focusable Large Field Corrector lens that is otherwise used when the standard NP127is is paired with a 16803 sensor. In addition, we’ve incorporated our unique image plane tilt correction from the standard Imaging System focuser. The scope came pre-focused and adjusted from Tele Vue. The idea is that imaging train will be as close to perfectly set up as possible right out of the box, but still allow some tweaking if necessary for FLI products already in customers’ hands. So this instrument is far more than just unscrewing the focuser of an NP127is and adding an extension tube!”

To the back of this is attached the FLI Atlas focuser, the Centre line filter wheel and a Proline 16803 CCD camera all using the FLI ZTA (Zero Tilt Adapters). As I already had the focuser and camera David and Greg Terrance from FLI shipped over the telescope and filter wheel with all the necessary adapters. Setting up was very straight forward and the time it took me to dismantle my imaging set up and swap filters over, change front plate on my camera, put everything on my mount including a guide scope and rebalance the system was about 3 hours, no extra tools were required as they are standard allen key fittings. The ZTA system is about the most secure system I’ve used in connecting components together and it such a secure fit that it is like welding the components together without using a torch!
Although David mentioned above that there is some tweaking available to the end user I didn’t find this necessary so the first light image is produced from the system as it arrived. From my perspective and first use it is truly “plug and play”. I will be using this system over the next few months so I will post my progress as it happens.
The sensor chip of the Proline 16803 is square with 4096x4096 9micron pixels with a diagonal of 52.1mm. My PL16803 that I am using has Anti Dew Technology fitted and has no cover slip on the chip. I am using 2” square filters in the Centreline filter wheel, the narrow band filters are all 5nm bandwidth. The camera is cooled to -35c and it manages to hold this temperature with ease even during warm summer nights
The image was taken over three nights and as the weather hasn’t been too good and after 2 false starts due to cloud I was keen to get some early results so I shot 10 minute sub frames with 13x10 minutes for Ha, 17x10 minutes for OIII and 23x10 minutes for SII. As I changed scopes I had to shoot all my flats again which was fairly straight forward. I am using an Officine Stellare Falco guide scope and Starlight Xpress Lodestar for guiding, with 5 second guiding exposures with dithering switched on.
I last shot this 3 years ago with a different camera/scope combination, this can be seen on my website http://www.imagingtheheavens.co.uk for comparison

A full size version is at the following link

http://www.pbase.com/imaging_the_heavens/image/151820147/original

Thanks for looking
Best wishes
Gordon

http://www.imagingtheheavens.co.uk/userimages/veilhst1000(2).jpg