Remote setup - sanity check

[AstroDivers]

Good evening everyone,

I have a complex situation where I would truly appreciate any help to verify that I am not making stupid mistakes.

Due to bad weather me and a friend are going to rent a remote setup in Spain, as a first testing step of going remote.

Until now we had our separate semi automated setup outside our backyards. I have a 130mm F/7 refractor, he has a 2400 12" RC. So we are looking for something in between.

Our idea for the remote setup:

Skywatcher QUATTRO 12" F/4 @1200mm

ZWO6200MM, 2" unmounted filters, ZWO Filter wheel (this combo I already have and i will move it from my terrace to the remote one)

Paracorr Type 2 3" (1.15x)

SESTO SENSO Esatto 3" motorized focuser

Skywatcher EQ8

Sampling

I've had a discussion with Vlaiv who was super nice and helpful with analysing sampling of this combo. We will bin 2x2 or 3x3 depending on the sight conditions. Thank you vlaiv!

Coma Corrector 

Since the camera is a full frame, a 3" focusser and coma corrector are mandatory to have a enough illumination, right?
Are there any alternatives to the paracorr maintaining a good quality?

Focuser

The autofocuser all in 1 from PRIMALUCE seems to have nice reviews online, sturdy, relatively cheap and will solve the problem of focuser + motor

Mount

What is the practical difference between a recent EQ8 and an old type one? We could save ~1k€ but I don't want any big downside. My friend has actually one 'not recent' EQ8 and it seems to work fine with the 12"RC

Guiding

What about guiding? OAG or separate scope? What would be a good guiding camera for this setup? We both use a ZWO120 mini, with nice guiding

 

Since we are going remote, any other accessory/consideration to be taking into account?

Wish you all clear Skies,

 

Luca

 

[tomato]

I’ve never owned a F4 Quattro but have read posts that they are not the easiest reflector to collimate. Will you have someone at the remote site who can perform this task if needed?

Wishing you every success with your remote setup.

[AstroDivers]

1 minute ago, tomato said:

I’ve never owned a F4 Quattro but have read posts that they are not the easiest reflector to collimate. Will you have someone at the remote site who can perform this task if needed?

Wishing you every success with your remote setup.

Hello tomato,

yes the site offer remote assistance (paid). Reviews seems to be very positive. We accounted for some man-hours required to periodically check collimation

I personally don't have much experience with Newtonians so I hope it won't be necessary ever night

[davies07]

Hello Luca,

That's an interesting setup you are proposing. Here are a few thoughts.

To be honest, I wouldn't go with the Quattro. I owned a 10" with a carbon tube and as Tomato said, they are a difficult scope to collimate well. I could collimate mine properly only after purchasing a Catseye kit and learning how to use it properly. A simple Cheshire sight tube and laser was not accurate enough. Moreover, I suspect the steel tube will move with temperature and will need frequent checking, as will focus. And yes, I checked the collimation every time I used it.

My second concern with a Quattro is that it is a very big, bulky tube. Adding a dew shield makes it longer and it will move in a breeze. I could not use my 10" in the open in the UK, the slightest breeze would move it.  I had to build a dome observatory to use it. 

You've got an expensive mount and an expensive camera, the Quattro feels like the wrong scope in terms of balance of costs to me. To be sure it will be very fast at F4 but you could compensate for a slower scope with more exposure time. The large aperture will promise high resolution but you will be seeing limited in practical terms. On the other hand, if a big Newtonian is the way you'd like to go then I would also look at the Teleskop Express OTAs. What's wrong with your friend's F 7 130 refractor? That might make a good start.  Or go for a 150mm Esprit. it will be less trouble, I'm sure. Believe me, living with a reflector telescope takes lots of maintenance time. 

I would look at the ZWO ASI 2400 camera. With 5.8um pixels and 100K well depth, I think it would be a better match to the 1200mm focal length and without sacrificing image size with binning. The 3.8um pixel size on the 6200 has half the well depth  and would be better on a shorter focal length scope. On your proposed setup 2x2 binning would work; 3x3 sounds too much to me. I would hope that you get better seeing than I do in the UK. Better seeing favours a longer focal length scope.

You'll need off-axis guiding. a separate guide scope will flex with respect to the main tube - the guide scope and main tube will move with respect to each other under gravity as they track. This was another problem I had with my Quattro; my maximum exposure time was 5 minutes due to oval stars caused by flexing.

An older EQ8 should be fine. I have an old one and get sub 0.3" rms tracking error using PHD2 carrying an 8" RC and a 107mm refractor; I use GSS to drive it.  The primary risk would be getting an old one that has been compromised by the fiddling of a previous owner - as I did. it was fixable but cost and took time. 

I hope these thoughts help your decision making. Good luck.

 

David

   

[wimvb]

I agree with what @davies07 wrote. My experience with remote rigs is that they’re much less remote than you’d want them to. (I host one for a friend.)

My advice is, choose a scope that is low maintenance. Run the full setup locally first for at least a few months, to verify that everything runs consistently, before you ship it off to a remote site. Don’t forget that you will also need to remotely control capture of calibration frames.

[Craig a]

I also own the Quattro 10 with carbon tube and collimation is difficult, at f4 room for error is tiny, I bought a concenter sight tube and that helped massively in getting the hardest part correct and that is the secondary, it’s a great bit of kit for that. I also struggle if there’s a wind outside at 1000 mm a breeze would ruin subs, I recently bought the starizona nexus coma corrector/0.75 reducer that brings it down to 750mm and f3, it’s not cheap but first impressions are good (only done 1 test so far though because of weather). 
for a remote setup I personally would go for a refractor being low maintenance like a esprit or similar depending on what you want to image.