PL16803 Window coating

[niharika]

Hi,

The standard window for PL16803 has an F101 coating and there is an optional upgrade with F116 window which is optimized for photometry. I have attached a window reflectance image provided by FLI.

At this stage I have no intention of using it for photometry but wondering if I should just get the upgrade which will reduce the efficiency in the visible light path by about 1%. What are your thoughts??

Regards
Raki

[Shiraz (Ray)]

For visible band imaging, I would get the lower reflectance coating - less chance of reflection artefacts (halos etc). 1% of Alnitak could do a lot of damage to an image. Ask FLI for advice.

[niharika]

Thanks Ray

[gregbradley]

I wouldn't. You pay a fortune for every last bit of QE and if you are taking pretty pictures I have not noticed a reflectance issue with the regular Proline.

If you look at Proline images you will see a little diffraction spike in one spot only on the brighter stars. I am not sure what that is but you don't see it on Microlines. I suspect its something reflecting inside the CCD chamber.

The bigger issue of Proline versus other types like Microline or another brand is weight. Not all scope's focusers can handle the weight without flex. Are you using TEC160FL? Its fine on the Feathertouch 3545. Not sure about the TEC focuser (I would have less confidence in that unless proven).

Greg.

[Shiraz (Ray)]

just to clarify, that's what I suggested as well - the standard low reflectance window, not the upgrade.

[Hans Tucker (Hans)]

Originally Posted by gregbradley

I wouldn't. You pay a fortune for every last bit of QE and if you are taking pretty pictures I have not noticed a reflectance issue with the regular Proline.

If you look at Proline images you will see a little diffraction spike in one spot only on the brighter stars. I am not sure what that is but you don't see it on Microlines. I suspect its something reflecting inside the CCD chamber.

The bigger issue of Proline versus other types like Microline or another brand is weight. Not all scope's focusers can handle the weight without flex. Are you using TEC160FL? Its fine on the Feathertouch 3545. Not sure about the TEC focuser (I would have less confidence in that unless proven).

Greg.

TEC Focuser
I though all TEC Refractors that were built since TEC Refractors (Starting with the TEC140) came on the market were fitted with the Feathertouch 3545 Focuser.

[niharika]

Originally Posted by gregbradley

I wouldn't. You pay a fortune for every last bit of QE and if you are taking pretty pictures I have not noticed a reflectance issue with the regular Proline.

If you look at Proline images you will see a little diffraction spike in one spot only on the brighter stars. I am not sure what that is but you don't see it on Microlines. I suspect its something reflecting inside the CCD chamber.

The bigger issue of Proline versus other types like Microline or another brand is weight. Not all scope's focusers can handle the weight without flex. Are you using TEC160FL? Its fine on the Feathertouch 3545. Not sure about the TEC focuser (I would have less confidence in that unless proven).

Greg.

Thanks for your input Greg. Yes the TEC is with FT3545. At some stage I might try to put it on my FSQ106N as well but that will have to wait till I get a Atlas!

[niharika]

Originally Posted by Hans Tucker

TEC Focuser
I though all TEC Refractors that were built since TEC Refractors (Starting with the TEC140) came on the market were fitted with the Feathertouch 3545 Focuser.

Yes, I think they started putting TEC focuser on from last year or so. Some say TEC focuser is better, some prefer the old proven FT. TEC was also developing a focuser automation to integrate with their new focuser but that never came to production and there is no clear indication on when it will come to production.