Considering full frame Osc

[Allinthehead]

Hi all. Well I've been having some dodgy thoughts recently about upgrading from an Asi 071 pro to a full frame osc. I image with a Takahashi Epsilon 130d. 

I'd love to hear some thoughts on this.

Richard.

[andrewluck]

From the specs on Takahashi America I see that the 130d has a 44mm image circle. The diagonal of a full frame sensor exceeds this at 49.5mm. I've no experience with this scope but with my FSQ-85 (same image circle specification), when I switched to a 16200 chipped camera the stars in the corners were very poor. This sensor is considerably smaller than a full frame. Now I've fitted the new flattener this has made a considerable difference.

I'd seek the advise of either Takahashi Europe or America and see what they recommend.

 

Andrew

[AngryDonkey]

6 hours ago, andrewluck said:

Now I've fitted the new flattener this has made a considerable difference.

Sorry for hijacking but would you know the backfocus distance for the flattener? Unhelpfully the manual does not seem to mention it....

[fireballxl5]

3 hours ago, AngryDonkey said:

Sorry for hijacking but would you know the backfocus distance for the flattener?

Back Focus Distance of the FSQ85 EDP Flattener is 56mm - see http://www.takahashiamerica.com/blogs/product-announcements/takahashi-announces-a-new-flattener-for-the-fsq-85/

[davew]

15 hours ago, andrewluck said:

From the specs on Takahashi America I see that the 130d has a 44mm image circle. The diagonal of a full frame sensor exceeds this at 49.5mm. 

Sorry but I have to dispute this. I worked out the diagonal of a 36 x 24 chip and it's 43.27mm. On FLO's specification for the ASI 094 it's 43.3mm . Another fly in the ointment is that most FF chips are smaller than 36 x 24 and the one that always seems to be quoted as too big and won't work is in fact a few mm larger than 36 x 24 ( KAI 11002 )

The Canon 6D has been reported as casting a mirror box shadow but I've seen images taken with that camera and the Tak. Quite what skulduggery is going on I don't know ! I've also seen Nikon D810a images and of course the Sony A7s. That camera won't cast a mirror box shadow because it hasn't got one.

I've also seen it reported that the Tak will vignette with a FF chip but can be flatted out ( there's an image of a flat somewhere on a review site ). This does mean the corners will get less illumination than the rest of the frame but this concerns some people and not others.

So ... my thoughts on this are contact FLO who may know or Ian King or someone who can provide a sample flat of what you intend using,

Dave.

[andrewluck]

No dispute there, you're absolutely correct. Finger trouble with the calculator here. Apologies for the confusion.

 

Andrew

[Allinthehead]

Thanks for the replies. What i'm thinking at moment is the chip that's in the Nikon 810, or the D600. Should i be considering a Ccd bearing in mind that i want to keep my subs 5 mins and below.