[Andy01 (Andy)]

Originally Posted by AlexN

With 2.5k to spend, I would buy a 2nd hand canon 300mm f/2.8 camera lens. It's wide, it's fast. It's designed with 35mm sensors in mind and the optics have proven themselves for astro imaging.

I just recently picked up (the second one I've owned now) a tokina 300mm f/2.8 for $900 .. If you are doing narrowband imaging with a kaf8300 sensor stars will resolve to an individual pixel at times but dithering and drizzle processing will make short work of that.

Interesting approach Alex - I was all set originallt to get the adaptor for 6x7 pentax lenses and a 165mm and 300mm 2nd hand, until I heard that QSI had ceased production of the adaptor.

Originally Posted by Camelopardalis

If you intend to use a full frame chip, then it'd be worth checking whether the SV can do that. The WO was designed for it. However, there have been a couple of reports on CN of Maltese cross shaped right stars. On the plus side, there are people out here using them with full frame chips and the images look really promising.

Camera lenses bring their own set of parameters that may or may not be ideal for AP...

Yes, I had heard of the cross shaped, even pyramid shaped stars on CN forums, probably the only thing holding me back right now.

Originally Posted by Slawomir

No worries Andy.

What about Zeiss FE 55mm F1.8 lens? Greg has one and his shot of Rho Ophiuchi with this lens is magnificent.

Here is the link - Greg, I hope you do not mind http://www.pbase.com/gregbradley/ima...91607/original

Slawomir, yes, see my comment above re: camera lenses

Originally Posted by SamD

Sorry, no help on the scopes you've mentioned, but with NB imaging at least, I've found that even inexpensive "vintage" camera lenses give pretty good results, and are fun and versatile for wide field nebulae.

Chromic aberration isn't a problem over the bandwidth of NB filters, and drizzle integration restores a lot of resolution.

Two that I enjoy using are a Carl Zeiss 135 f/3.5 and a Takumar 200 f/4, both with M42 screw fittings.

Yep, not sure If I want to put a 35mm camera lens on the QSI though. though, issues with image circles and covering power are often mentioned.

Originally Posted by Retrograde

Hi Andy,

what about something like the Borg 71FL? It has a focal length of 400mm.
They also have a Feathertouch option (which adds significantly to the cost of course).
I believe it will cover full-frame when using one of their flatteners or reducers.

Wow, I googled the Borg and it does seem resistance is futile! Pricey though bet well worth further investigations. Cheers