180mm F10 and Quark Combo

[AndiesHandyHandies]

Hi

Is it feasible to use a 4x Telecentric for 7200mm focal length and get an image on a chip.

Whats the best option for a focal reducer if it is possible?

Cheers. Andrew.

[pupak]

It depends on your viewing conditions. If they are excellent, the focal length of 7m is not a big problem for a camera with IMX432 or IMX533 BIN2-3.
Good reducers are produced by Baader, 0.7x and 0.4x. They are intended for solar telescopes.

[marktownley]

Hi

Is it feasible to use a 4x Telecentric for 7200mm focal length and get an image on a chip.

Whats the best option for a focal reducer if it is possible?

Cheers. Andrew.

You can get an image on a chip, what camera are you using? The pixel size will dictate the factor of the reducer.

Personally, if you are going f10 then get a TZ3 rather than TZ4.

My alarm bells ring more about local seeing at this aperture.,

[AndiesHandyHandies]

Hi Mark,

Well Baader seem to like F30, for their 6" F15 solar Coude'?

I have a 1.25" 3x VK Telecentric I can try.

I have no large camera at the moment. I can borrow a 174.

Occasional use of course. So on hand bits. I have a standard 0.5x.

I have a reasonable site for seeing on a cliff edge with field beyond. Till we reach a church.

Cheers. Andrew.

[AndiesHandyHandies]

Hi

For visual.

Using a Combo Quark at 6x on a F6.7 90mm at F40 and 3600mm FL works OK.

And my new 80mm F15 likes 2x at F30 and *** 2400mm *** FL.

I am sure the Mak 180mm F10 will do OK with a 2x Extender for 3600mm FL for visual. I think longer in the past was too much.

Cheers. Andrew.

[Dennis]

Hi

For visual.

Using a Combo Quark at 6x on a F6.7 90mm at F40 and 3600mm FL works OK.

And my new 80mm F15 likes 2x at F30 and 3600mm FL.

I am sure the Mak 180mm F10 will do OK with a 2x Extender for 3600mm FL for visual. I think longer in the past was too much.

Cheers. Andrew.

I think with the Quark combo you want at least F/30 at the etalon. Reducing would be afterwards but the etalon is so small that its not suited for visual use in this case. So you need good seeing for visual use at F/30.