Paramount Taurus

[Somnium]

it looks like SB has a new toy ... this looks like an absolute beast! on axis encoders, a Fork mounting and 180 kg payload. it is more expensive than the comparable Mathis mount but i don't believe that has absolute encoders on it.

https://www.youtube.com/watch?v=d6Dr3cpFc54#t=10

http://www.bisque.com/sc/pages/ParamountTaurus.aspx

soooooo when can we expect someone on this forum to dish out the cash for this baby ?

[gregbradley]

That's a pretty sophisticated piece of machinery. I take its for 20 inch RC/CDK and above.

I wonder what the benefits of an Alt Az mount over a GEM? No meridian flip is the obvious one.

Greg.

[el_draco]

Well, it was inevitable but thats institution class. No meridian flip but thats at the price of flexure. 180kg hanging out there is going to be an issue...

[Somnium]

it would be nice not have to meridian flip :)
Flexure might be an issue but when you are looking at 180kgs, the only other option is an alt az mount with a field de rotator and i would imagine that having another step in the process would be worse ... but hey this is way out of my budget anyway

[PTW]

With TPoint and ProTrack the fork flexure will simply go away. The requisite term (FO) is already in the basic repertoire of terms that the default model includes. Bear in mind that GEMs also flex, but differently: in their case it's from the sagging of the cantilevered declination axis (TPoint term DAF).

The elimination of meridian flip is an enormous advantage. And quite apart from uninterrupted exposures across the meridian, the fact that a much smaller range of mechanical declination will be used makes modelling easier. And no counterweights. GEMs are nasty!

[gregbradley]

Nice to see you post here Patrick.

Greg.

[Octane]

When do you get yours, Greg? :P

H

[rogerg]

Before I bought my PME I searched high and low for a good fork mount equivalent. Coming from LX200 fork mounts it is a real PIA having a GEM. I'd switch to this in the blink of an eye if I had the $$$$. Love fork mounts. None of this meridian rubbish :)

[gregbradley]

:lol: I am on a restricted Astro dollar diet! I'm too astro fat.

Greg.

[Paul Haese]

I like the idea too of no meridian flip. Price is a bit steep for me too at present.

[Somnium]

might be a little big for the 12" RC :)

you would need a 20 - 24" scope for it ... so 50k plus the mount ... anyone got a spare 100k to trial this tech out ?

[Bassnut]

Well, Mike n Trish (Placidus) have a Mathis MI750 fork with a 20" CDK on it which lists for US$19600 155kg payload vs starting price US$35000 180kg payload for this SB, thats quite a premium, both handle a 20" easily.

Granted, Mike designed and built his own controller/software for the MI750, but it seems SB is banking on brand name and controller/software included for this hefty premium (output encoders look to be an extra option).

[gregbradley]

Yep. I'd rather get an AP 3600 with encoders and latest just released controller electronics.

Greg.

[Somnium]

also, if that mount is a little on the cheap side ... planewave are now offering a 1m telescope ... for the price of a decent house

http://planewave.com/products-page/cdk700/pw1000-cdk-telescope-system/

granted this is more of a research/university instrument but i am sure someone will have big enough astropockets :)

[Atmos]

My one single reservation for alt/az systems (requiring a field derotator) is that of accurate flat fielding. With its reported ~9% vignetting across a 100mm imaging circle it may not seem like the biggest of issues but I do have a little OCD for accuracy in scientific measurements. Don't get me wrong, it only means you need a 360º flat field but that does sound like a bit of a PITA :P

This telescope has been on my dream list since I first heard about it near two years ago :rofl:

[Somnium]

i haven't really thought of that, but most, if not all, large telescopes are alt az mounted these days. i am sure this is not a major issue. you might need the dry ice cleaning system like the Subaru telescope to get rid of those dust bunnies :) why not go all out ?

[PRejto]

OK, what am I missing? How does a mount have anything to do with a flat field? Isn't a FF just a measurement of the optical system? So what if the FOV rotates during exposures. Dust and vignetting would be constant. It's just the illumination on the chip quite separate from what the chip sees as an imaged object that counts, no?

Last week I was at AIC and attended a lecture on flats given by Peter Kalajian. A question was asked about the contribution of dust on the objective to FFs. His response was that the dust was so out of focus as to not register. I would take that to mean that rotating the camera and filters would still give an excellent flat even if the objective/primary mirror were fixed. I think most rotators rotate everything following the focuser and not just the camera.

Maybe the confusion is about gradients. Those would rotate. I'm not sure how that might impact on removal. Perhaps not all all with the PIX tool.

Peter

[Somnium]

what about the tertiary mirror, that is quite a bit closer to the focus, but overall i agree, i dont see this as an issue

[PRejto]

Sure...interesting academic discussion. Do you know anyone actually doing this (imaging from an alt az mount with a rotator)?

Peter

[gregbradley]

Roland Christen commented on this a little while ago. Rotating the camera ordinarily would have no effect on the flats.

If you have an obstruction in the scope or imaging train that does not rotate then yes.

Dust donuts and vignetting though will simply stay the same.

Dust on the objective does not show up in flats only dust on filters or the CCD glass chamber.

Greg.

[billdan]

The main issue with camera rotators is they are useless near Zenith where the best seeing is. Fifteen degrees either side of Zenith is forbidden territory as the camera is rotating too fast.

When I researched this about 3 years ago, most rotator users gave up in frustration after 12 months and went with a Wedge or an EQ platform instead.

Bill

[Atmos]

Having accurate flat fields in professional observatories is a real pain in the neck and rotators are just one of those necessary evils. If you take flats, rotate the camera and then divide those flats from one another, it won't be a perfect removal. Unless you have an uncreatably perfect primary and secondary mirror, no flexure of any description whatsoever and onthogonal to within less than a micron, you are going to have different gradients when rotating a camera. Although it isn't likely to be enough to make a noticeable effect on the background as it may indeed look perfectly flat, scientists are trying to get sub milimag precision for photometer if and astrometric studies. I remember reading a paper a while back that mentioned that as much as 3% imprecision caused by the sheer difficulty in getting perfect flats.

[rustigsmed]

it would be a tough call ... grab the 1m or three 0.7m for the same price (or cheaper!)

[Somnium]

i think a more valid question is am i selling 1 of my children or all three ...