top end widefield imaging scopes?

[rocketandroll]

Hi folks... Well, it's been a while since I've been on here! Having had to sell most of my equipment and not been living anywhere viable for imaging I'm now just a few months away from hopefully moving house and getting a permanent obsy set up.

My plan is to get back into deep sky imaging but in a much more serious way.

In terms of scope I was veering towards the fastest option I could go for as my imaging time (and innevitably the weather windows) will be short. My plan had been to get an Oficina Stellare Veloce RH200 at f3 but having been looking in more detail I've seen quite a few images from the scope that look a bit 'fuzzy', I am guessing that may be down to the difficulty of achieving focus on such a fast scope?

The alternative option is maybe a Tak with a focal reducer as every image I've seen from one is sharp as a pin. That's obviously however not quite as fast.

I'm just not sure which will give the best performance as ultimately I'm looking to make images I can hang on the wall at fairly large scale.

Anyone got any 1st hand experience that may help make a decision?

My other consideration that may affect the decision is that I want a low maintenance option I can leave set up and which needs minimal work to get set up each session.

Thoughts?

Thanks!! Ben

[swag72]

Low maintenance option you say? Well in that case you've just put yourself in the market for a Takahashi! Refractors are the most plug and play that you can get. For me it would be a no brainer, Tak all the way.

When you say widefield, you don't give any indication of budget. The FSQ106 and a 11000 chip CCD is about as wide as you can get. Have you looked at Olly's images? He's doing some great work with this combo.

[rocketandroll]

Cheers mate...

Nope, not seen Olly's recent work, but not seen anything bad come from him ever so I certainly trust his opinion on equipment :-)

Budget wise, the FSQ106 and Veloce are both about the same sort of price range, around the £4K mark so that is roughly what I was aiming at. Total budget for the rig is about £10K so, assuming a NEQ6 will do as a mount (never had any problems with my HEQ5 and I have no intention of mounting anything heavy enough to warrant a paramount or anything massive like that) and allowing a grand for guiding equipment that leaves about £4K for a CCD though if I could get it for less than that then great. My plan is still currently to go with one shot colour as the next obvious step from DSLR work but may look at going over to narrowband later. I have also considered an astro-modded Eos 5dmk2 but not sure if anyone will commercially astro-mod a higher-end DSLR?

The Veloce appeals due to the sheer speed but with the reducer the Tak comes down to f3.9 which is not to be sniffed at and... I don't think I have ever seen a bad image come out of a Tak :-)

Ultimately my plan is to add a second longer focal length scope to the rig with a smaller CCD and carefully align both to capture detailed and widefield data on the same subject similtaneously and/or have something more suited to galaxies etc... but that'll be a couple of years further down the line... so long as the mount will handle it we'll be fine.

Ben

[rocketandroll]

Actually, Swag... do you have any specific recomendations on CCD's? Or maybe Olly does?

Having been 'out of the loop' for a year and a half it seems some new things have come along. I have been quite a big fan of Starlight Xpress cameras and their very good customer support but I'm happy to look at all makes for such a high cost purchase.

I am keen to carefully match overall resolution with chip size and pixel size to get what I need for the targets I want to capture.

Ben

[swag72]

I can only recommend the Atik 460EX mono as that is what I am using at the moment. I know that Olly loved his 4000 on the FSQ85. Starlight have just bought out a new range of CCD camera's - They look good.

Personally if I was doing it again, I think I'd look with something such as a QSI that has a built in filter wheel.

[rocketandroll]

Yeah, I am certainly tempted by the OSC/Ha option to bring out more in neblae before, as mentioned, maybe moving on to full narowband work later, so having a built in filter wheel sounds like a nice option to avoid getting to know a camera then having to change again after a year or two.

Ideally I want something with quite a physically large sensor but with small pixels, sub 5nm ideally and at least 6-8mp.

Gonna have to do some serious homework on what's out there and what suits my needs best :-)

[perfrej]

Go for Takahashi quality. The speed is adequate and you get the wider field of view by using a CCD that has a large chip area. I am not a fan of reducers as they introduce yet another piece of glass for added fuzziness

Ideal would be an 85 or 106 with an 11000-based camera (or 29050 if you are willing to spend serious money).

In respect to imaging at f/3 with a Veloce... You get the light fast and you get hte light pollution and sky glow equally fast. Hehe...

/per

[JamesF]

There was a thread a while back on OSC vs. mono. If you've not read it then it might be worth hunting down. I don't think it's necessarily the case that OSC is actually faster than mono.

James

[swag72]

Ideal would be an 85 or 106 with an 11000-based camera (or 29050 if you are willing to spend serious money).

I hope Olly will see this and jump in - He tried the FSQ85 and the 11000 ............... Suffice to say I now have his FSQ85 and he has an FSQ106!!

[JamesF]

I hope Olly will see this and jump in - He tried the FSQ85 and the 11000 ............... Suffice to say I now have his FSQ85 and he has an FSQ106!!

My recollection is that he couldn't get the FSQ85 to light the corners of the 11000 sensor.

James

[rocketandroll]

Cheers both.... James, I assume you mean that having to take multiple channels isn't necessarily going to take longer than capturing the same data with a OSC camera?

Obviously I know mono CCD's are more sensitive... it'd be an interesting consideration if the extra sensitivity outweighed the time cost of having to take multiples of each shot for each channel.

My biggest concern is having short windows of opportunity and having to accurately guess how long I have so I can get equal numbers of exposures for each channel. I liked the ability to just 'grab a bit more' when I was imaging with a DSLR if I found I had more time. Whereas an extra 20 minutes with the DSLR made a big difference... however with 4 channels and 10 min exposures that'd only get you an extra exposure on two channels.

My problem was not having a permanent set up so it was near impossible, and took over an hour of set up to try and get the scope pointing in vaguely the same direction which made images gathered over multiple nights nigh-on-impossible. With a permanent obsy and the proper software it may be far easier this time round.

Ben

PS: Re; LP on the Veloce... I guess it will collect LP faster too but... S/N ratio will stay the same so that won't make any difference to the data will it? Or was that a joke? :-)

[JamesF]

James, I assume you mean that having to take multiple channels isn't necessarily going to take longer than capturing the same data with a OSC camera?

Yes, basically. And even more so if you use binning on the RGB captures. If you're worried about not capturing all the data then with an electronic filter wheel you could potentially cycle the exposures so you capture in turns.

James

[DaveS]

I posted this above, but if you're will to wait a bit and take a chance with something not Tak this might prove interesting.

http://www.firstlightoptics.com/vixen/vixen-sd-100-f38-flat-field-refractor.html

They also (apparently) do a reducer to f/3.0 and an extender to f/6

[rocketandroll]

Hmmm... that looks rather nifty :-)

Waiting wise, I'm not buying till the end of this year at the earliest anyway, so that's not an issue.... it's a little shorter focal length than I was aiming for but could certainly be a good cheaper option.

Thanks for the link :-)