SW Quattro 10" vs 12" for imaging

[SamAndrew]

13 hours ago, Northernlight said:

My camera is a QSI 683 with 5.4 micron pixels,  so it's a fairly decent match to both the 10" & 12" 

10" - 1.11" per pixel   /  12" - 0.93" per pixel

Given the choice, I'd go with the 12" for galaxies given you've got an EQ8.

These Newts are relatively cheap, you can also pick up an 8S second hand for a few hundred and the switch between the two when you want to change field of view.

[Northernlight]

21 hours ago, vlaiv said:

Looking at your signature - you seem to have 8" GSO RC?

What sort of FWHM do you get in your subs (in arc seconds) with that scope and said camera on EQ8 mount?

 

Vlaiv,

I dont like the RC, even using it reduced down to around 1m F/L, but i struggled with wierd reflections from time to time and i found that flats could also be a pain in the end i grew tired of it, and wanted something a bit bigger and a bit faster.

I also want something that i can also use visually, as the RC was no good in that respect due to large central obstruction.

I'll probably keep it and maybe play around with it again in the future.

[toxic]

just an example of what you can see after capture i am not good with maths.
the 10s Quattro is fitted with the Sky-Watcher f4 Aplanatic Coma Corrector
and the 200 pds F5 was fitted with the sky-watcher 0.9x coma corrector.
so more or less the same f ratio and tube length, so you would think they would perform very similarly but in real world they do not.
2 sample pics un edited just converted from fits to jpeg for posting.
image 1 in  ---- Quattro 10s ---120 seconds atik 383L+m.
image 2 in  ------- image 200pds 300 seconds atik 383L+m
all other kit is the same

 

[vlaiv]

40 minutes ago, Northernlight said:

Vlaiv,

I dont like the RC, even using it reduced down to around 1m F/L, but i struggled with wierd reflections from time to time and i found that flats could also be a pain in the end i grew tired of it, and wanted something a bit bigger and a bit faster.

I also want something that i can also use visually, as the RC was no good in that respect due to large central obstruction.

I'll probably keep it and maybe play around with it again in the future.

I just wanted to know what sort of FWHM were you getting with that scope.

That is important for sampling rate - I have feeling that even 1.1"/px will be oversampling but that really depends on usual FWHM that you get in your sky and with your mount / guiding.

Ideally, sampling rate that you should target is FWHM that you usually get (or best values if you want to "be ready for those perfect nights") in arc seconds divided with 1.6.

[Northernlight]

Many thanks Chris

I'm really struggling making a decision on this - I'm torn 3 different ways :-

1) Buy 10" Quattro and upgrade the focuser, springs etc   (chapest options but none available until end of Oct)

2) Buy the 12" quattro - upgrade focuser & springs as well as flocking the entire tube (Can't get the focuser upgrade i want - but is available in 2-3 days)

3) Wait until the end of the year and get the new design 10" F4 Lacerta when it's finished an ready to ship (will be superbly built and most likley hassle free, but also 3x price of option1 and 2x price of option 2)

Rich

[Northernlight]

6 minutes ago, vlaiv said:

I just wanted to know what sort of FWHM were you getting with that scope.

That is important for sampling rate - I have feeling that even 1.1"/px will be oversampling but that really depends on usual FWHM that you get in your sky and with your mount / guiding.

Ideally, sampling rate that you should target is FWHM that you usually get (or best values if you want to "be ready for those perfect nights") in arc seconds divided with 1.6.

I'm trying to remember what the average was on half decent nights - i'm sure it was usually anywhere between 1.6-2.0, but then again my memory is not the best. I normally imaged at around 1070mm F/L @ about F5.4

 

 

Edited August 27, 2020 by Northernlight