Can one of our resident Tak experts please help. I just received an order that I am not sure is correct.
I am trying to connect my Canon EOS to my FS-60CB, and looking at the system chart for this scope - the configuration that includes the flattener is what I am hoping to acheive - its the 3rd from the bottom.
I ordered a wide T-mount part (number 33 on the chart) Part No. TKA20233, and I don't think that what i got is correct, or I ordered the wrong Part Number - can someone enlighten me please. I have attached a photo of the part I received.
Thanks
Adam
Last edited by adman; 04-04-2011 at 11:25 AM.
Reason: added photo with measurements
I had a wide T-mount that I used with my ED80 reducer - but that got sold with the scope. Will any wide T mount do, or do I have to get the Takahashi one...?
Adam, Paul is correct, here is a photo of mine for the Toa130 and a 40D. sorry the image is a tad blurry, but I think you can see that the part you got fits into the T adapter and is locked down by the grub screws on the T adapter.
Adam, I have added the image of the T ring from the Bintel shop, this is what your piece fits into.
The part you have got is the correct part for the FS-60, you should have specified that it was for an EOS camera, the part then would have come with the correct EOS ring already attached.
I would say that you are going to have to order the EOS ring, only thing is that I don't know if it is a special size or not to suit the Tak Wide T-Mount. Note that this is a special size for the FS-60.
The order is then CAA, SD Ring, Flattener then Wide T-Mount.
ahhh - yep it all makes sense now - I might be able to remove that part from my exisiting adapter and replace it with the Takahashi one - will have to check when I get home..
Hi Adam,
I'm sure the guy who bought your old scope will let you borrow the adaptor to try on your new setup.
I believe he's very easy to get along with........
Adam, I can confirm the T ring shown on my post from Bintel, does fit my TOA130 setup as shown. I bought a spare yesterday as the original was getting sloppy.
Hi Adam,
I'm sure the guy who bought your old scope will let you borrow the adaptor to try on your new setup.
I believe he's very easy to get along with........
Cheers,
Ken.
Thanks Ken! That might be handy before I go and order something that is bound not to be the right one
Adam, I can confirm the T ring shown on my post from Bintel, does fit my TOA130 setup as shown. I bought a spare yesterday as the original was getting sloppy.
Thanks Peter - would you please be able to measure the diameter of the opening on the bayonet part that my adapter would fit into. I'm not sure that they would be the same for the 130 and the 60...
The adapter in my picture above is approx 52mm across the camera end and 60mm across the scope end....
Adam, the diameter that the tak part fits into is 52.2mm measured with a pair of calipers. The actual diameter of the tak "male" ring is 51.5mm measured with the calipers, so this gives 0.5mm play for the grub screws to take up. The diameter of the threaded part that screws into the scope(CA35) is 53.7mm. So it appears to me as though all you need is the part which I have photographed which is available from Bintel.
I have a wide T-mount adapter for my FS-60CB and Nikon somewhere. I can go for a hunt and find it if that's any help. It did come in two parts and I had to fiddle around to put it together.
I have a wide T-mount adapter for my FS-60CB and Nikon somewhere. I can go for a hunt and find it if that's any help. It did come in two parts and I had to fiddle around to put it together.
Cheers,
Rick.
Thanks Rick - I'm sure you will have the same part as I have pictured above, but a different bayonet obviously...
I have screwed the ring to the scope, but don't have the bayonet part . Ken has offered to let me have my old one back temporarily to see if it fits. Thanks for the offer though!
Adam, the 52mm is the critical one to fit the T ring for the camera. Mine is 51.7 and it fits the Bintel T ring perfectly. There is just enough play so that the grub screws take it up. I am 100% sure the Bintel one will fit.
I was labouring under the misapprehension that the 60mm outer diameter of my ring had to fit completely inside the bayonet part of the T-ring - but the short 6-7mm lip on the scope end looks like it is important for the distance from the flattener to the sensor - so it is meant to sit out of the T-ring.....duuuhhhh!
So yes Peter you were completely correct. It even fit the t-ring I had for my MPCC.
Thanks to all who helped - including the bloke at Bintel!
I took some images with this at Ten Chain Hill on Saturday night (between predicted and actual showers of rain ) and even with the flattener I am still getting way too much coma - see attached...
So, I have 2 questions:
1. in the system chart attached to the original post, the configuration third from the bottom shows what I interpreted to be an optional "SD Ring", whose function is a little uncertain, but seems to give you a closer minimum focusing distance. Would the presence or absence of this SD Ring affect the amount of coma?
2. The T-ring i used is the only thing in the setup that is not 'kosher' Takahashi gear. I would imagine that the thickness of the T-Ring plus Tak adapter (shown in original post) would be more crucial for coma - can someone please enlighten me?
When I ordered the wide t-mount, the actual bayonet part was accidentally not included with the shipment - but is on its way to me as we speak...
Adam
EDIT - the three images below are from left to right
1. A crop from the top left corner
2. a crop from the centre
3. the original image - jpeg'd and reduced to 25%...
Last edited by adman; 04-04-2011 at 01:29 PM.
Reason: images
Adam, if you are using the refractor which I gather you are, you should not be getting coma. More than likely you have some sort of field rotation. If the stars are elongated in the same direction across the whole image I would say this is what you are getting. You have a flattener in the system and this should stop any peripheral elongation. I am getting something similar at present and have narrowed it down to my all up weight being a tad too much for my G11. My guiding is very good. Not sure if you mentioned your guiding, but make sure the clutches are not slipping as I have found this can cause "eggy" stars as well.
I took some images with this at Ten Chain Hill on Saturday night (between predicted and actual showers of rain )
Adam
Hey - you saw the rain coming on the weather radar too!!! I can't help it if it disappears 2km down the road!!
Peter - I saw the original image on the screen. The "egginess" was radial, not circular, so I don't think it's field rotation. The tracking graph was pretty good too.
My hunch is something to do with spacing. I'll see if I can track down the relevant webpage with Tak reducer spacings - I found it recently when trying to order some custom adapters.
Adam, if you are using the refractor which I gather you are, you should not be getting coma. More than likely you have some sort of field rotation. If the stars are elongated in the same direction across the whole image I would say this is what you are getting. You have a flattener in the system and this should stop any peripheral elongation. I am getting something similar at present and have narrowed it down to my all up weight being a tad too much for my G11. My guiding is very good. Not sure if you mentioned your guiding, but make sure the clutches are not slipping as I have found this can cause "eggy" stars as well.
Thanks Peter. I shouldn't have used the term 'coma' - I am just used to using it when referring to my newt. Tell you the truth - I don't even know what the hell you call it when you get it from a refractor - spherical abberation? off-axis distortion? . Anyway it's what you're trying to get rid of by using a field flattener on a refractor.
The eggy stars are in a radial pattern. You can see from the centre crop image that the stars are reasonably round (please ignore the noise from my 550D at 30 degrees C), the crop from the top left is representative of the other corners - the distortion all points towards the centre of the image. So definitely not guiding/clutches or field rotation.
. Ken has offered to let me have my old one back temporarily to see if it fits. Thanks for the offer though!
) and even with the flattener I am still getting way too much coma - see attached...
