Quote:
Originally Posted by JA
Hi Stephane,
What you need depends a little on what you've got.
If you have a 2 inch focuser (I'm reasonably certain that your Bintel 200 f/5 would, but it pays to check). It says it has a 2inch to 1.25inch adapter so it's very likely unless your scope is modified somehow. OK so let's go with a 2 inch focuser (that's its internal diameter).
Your Nikon: is it full frame, APSc or other sensor size? This is important to know as for full frame you need as large an internal adapter diameter as possible otherwise you will vignettte (cut off) the light to the ~43.3mm diagonal of the sensor by using the M42 type T-ring. On full frame you want a "large" t-ring type thread, ususally it's M48. So it would be important to also know about the t-ring you already purchased is it an M42 or M48 thread? It may say so on the t-ring itself. By knowing this you can then order the right telescope adpater tube to the camera, which is essentially a 2 inch outside diameter tube at one end and an M42 or M48 male thread at the t-ring (camera end) of the tube. This in turn screws in to the t-ring female thread (mounted on the camera).
Usually (sometimes?) the INSIDE of the telescope end of this tube also has an M48 female thread in to which you can screw your 2 inch (M48) filters.
If you purchased the scope from Bintel I'm sure they could hook you up with the right stuff.
Best
JA
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JA, thank you for your reply. My Nikon D7000 has an APS-C sized sensor. Thus, I am assuming an M42 thread will work without vignetting? I forgot to mention that the Bintel OTA is a second hand “never used” piece that I bought off gumtree. I did this because Bintel is out of stock, and will be for months to come. All original accessories are included so the 2” to 1.25” adapter should be there… From photos I’ve seen, it does look like there is a two inch female thread on the OTA, but might check with Martin.
If I understand what you are saying, I should avoid the 1.25” T-Adapter, and rather get a 2” one (M42 being sufficient).
Also, would a coma corrector such as the Baader MPCC MkIII “replace” the T-Adapter?
Many thanks,
Stéphane