Which of these is best for AP

[Kenza]

Omegon 150/1000 ED Triplet 5890 EUR

Skywatcher Esprit 150/1050 5849 EUR

APM Doublet ED Apo 152/1200 mm OTA 4000 EUR

Takahashi Epsilon 180 OTA 5600 EUR

[swag72]

What scope do you currently use and what mount are you planning on using?

[ollypenrice]

This is a strange shortlist because the scopes are so different. The refractors are all slow which is a big negative for AP. (I have a TEC140 which is a lovely scope but F7 is not the best for imaging.) SInce you don't mention the f ratios of any of these scopes I wonder if you realise how important it is?

The Tak Epsilon is a real astrograph, incredibly fast at F2.8, and has a huge flat field. It also has about half the focal length of the refractors so is a widefield instrument. It will be about 6 times faster than the refractors so 10 minutes exposure in the Tak compares with an hour in the others. If you are going to use a DSLR ( limited to shortish exposures ) it has to be the Epsilon. You will never get good signal to noise at F7.

Since the Tak has a short focal length and fast f ratio guiding will be much, much easier.

I like big refractors but if I'm honest I'm no longer sure that they are the best way to go for imaging at around a metre of focal length. The Russian Photo Maks are faster and have superb resolution. By the way, I'd put a TEC refractor well ahead of anything on your list.

Olly

[Kenza]

This is a strange shortlist because the scopes are so different. The refractors are all slow which is a big negative for AP. (I have a TEC140 which is a lovely scope but F7 is not the best for imaging.) SInce you don't mention the f ratios of any of these scopes I wonder if you realise how important it is?

The Tak Epsilon is a real astrograph, incredibly fast at F2.8, and has a huge flat field. It also has about half the focal length of the refractors so is a widefield instrument. It will be about 6 times faster than the refractors so 10 minutes exposure in the Tak compares with an hour in the others. If you are going to use a DSLR ( limited to shortish exposures ) it has to be the Epsilon. You will never get good signal to noise at F7.

Since the Tak has a short focal length and fast f ratio guiding will be much, much easier.

I like big refractors but if I'm honest I'm no longer sure that they are the best way to go for imaging at around a metre of focal length. The Russian Photo Maks are faster and have superb resolution. By the way, I'd put a TEC refractor well ahead of anything on your list.

Olly

Sorry , forgot to mention the f ratios. I know their importance. Omegon is 6.7 , Skywatcher is 7 , APM is f/8 doublet.

[Kenza]

What scope do you currently use and what mount are you planning on using?

Currently I have an Equinox 120/900mm f/7.5 mounted on an EQ6 Syntrek. I plan to keep the mount.