Upgrading from 130PDS to refractor

[Deeko]

Hello!

After a year of imaging with  the 130PDS / HEQ5 Pro / ZWP 294MC combo Pro I am thinking of getting a nice refractor upgrade. I am currently looking at the Esprit 80, but doesn't look like a great match for the 294MC in the CCD suitability calculator: https://astronomy.tools/calculators/ccd_suitability Could anyone pass their informed comments on this please? 

The Esprit 80 is at the upper end of my budget and wonder if anyone could make any other suggestion that go well with the 294MC that are less or similarly priced? Also looked at Explore Scientific ED80: https://www.rothervalleyoptics.co.uk/explore-scientific-ed-apo-80mm-f6-essential-ota.html , which is just a bare bones kit and needs all the required extras, but is a good match on the CCD suitability calculator.

D.

[Ronclarke]

Have you checked out the SW ED80 ??

[vlaiv]

What would be the main reason for this upgrade?

130PDS is very close in performance to most budget refractors (80-100mm). Differences being of course diffraction spikes and need for coma corrector. Other than that it will outperform refractors in light gathering having greater aperture.

If you are looking for wider field setup - then don't bother with "suitability" calculator - get something like Esprit 80 or TS 80 triplets with matching field flattener / focal reducer to get to somewhere around F/4.5 or so and you will have great wide field setup.

If your primary reason for upgrading is that you want "less fiddly" scope / no collimation, but don't want to go wide field or give up on aperture - have a look at this scope then:

https://www.teleskop-express.de/shop/product_info.php/info/p6880_Explore-Scientific-MN-152-f-4-8-Maksutov-Newtonian-Telescope-with-Field-Correction.html

 

[Deeko]

1 hour ago, vlaiv said:

What would be the main reason for this upgrade?

130PDS is very close in performance to most budget refractors (80-100mm). Differences being of course diffraction spikes and need for coma corrector. Other than that it will outperform refractors in light gathering having greater aperture.

If you are looking for wider field setup - then don't bother with "suitability" calculator - get something like Esprit 80 or TS 80 triplets with matching field flattener / focal reducer to get to somewhere around F/4.5 or so and you will have great wide field setup.

If your primary reason for upgrading is that you want "less fiddly" scope / no collimation, but don't want to go wide field or give up on aperture - have a look at this scope then:

https://www.teleskop-express.de/shop/product_info.php/info/p6880_Explore-Scientific-MN-152-f-4-8-Maksutov-Newtonian-Telescope-with-Field-Correction.html

 

I am indeed looking for a wider field setup with the bonus of no more collimation thrown in, though the fiddly part doesn't bother me that much.

[Stub Mandrel]

It's interesting. I decided to go for a refractor, in the end I made a 66-400 using a Skywatcher 66 ED lens cell. Quite small and slower (f6 compared to F4.5) than the 130P-DS.

It has a different FOV and does give lovely results, but aside from the FOV and star spikes there's little difference, plus I only collimate the 130P-DS about twice a year, it just doesn't go out of collimation.

So my advice is get something of significantly longer or shorter focal length, the 80ED at 600mm is virtually identical to the 130P-DS at 590mm, and a much slower scope. So you are spending a lot of cash but not actually adding any options to your armoury and increasing the exposure time.

[vlaiv]

8 minutes ago, Deeko said:

I am indeed looking for a wider field setup with the bonus of no more collimation thrown in, though the fiddly part doesn't bother me that much.

Then just don't worry about sampling rate. In wide field setups you need to pay attention to fully corrected circle and sensor size. You are not after finest detail so actual sampling (or rather under sampling) is of no particular concern. 4/3 sensor size like 294 should have no issues with field correction on 80mm triplets with suitable field flattener.

[vlaiv]

4 minutes ago, Stub Mandrel said:

It's interesting. I decided to go for a refractor, in the end I made a 66-400 using a Skywatcher 66 ED lens cell. Quite small and slower (f6 compared to F4.5) than the 130P-DS.

It has a different FOV and does give lovely results, but aside from the FOV and star spikes there's little difference, plus I only collimate the 130P-DS about twice a year, it just doesn't go out of collimation.

So my advice is get something of significantly longer or shorter focal length, the 80ED at 600mm is virtually identical to the 130P-DS at 590mm, and a much slower scope. So you are spending a lot of cash but not actually adding any options to your armoury and increasing the exposure time.

Indeed. Scope like 80mm F/4.5 or there about (~360mm) will give about x3.25 FOV increase (~x1.8 in both width and height), so can be considered wide field upgrade over 130PDS.

Either 80mm F/5 or F/6 with riccardi FF/FR (x0.75) will get you that sort of focal length.