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In addition to the Alan Gee & the provided 19mm spacer tubes, I would need:
BTA T-adapter
Baader Varilock 29 (at 20mm position)
Baader Centering ring
Is that correct?
Thank you.
Thank you,
Ron DiIulio, Director
Astronomy Program
University of North Texas, USA
I religiously followed the instructions from the manual, page 12: I bought the #2454410 centering ring, the short BTA #2408160, kept the two supplied 19mm spacers with the Telecompressor, and used 45.5mm T2 spacers to achieve a 121mm working distance. Surprisingly, that yielded an effective focal ratio of f/D = 5.2, which was way too low (stars in the corner were distorted). I then removed the 45.5mm T2 spacers completely, and got around f/5.6 (still a bit of star distortion but quite less so).
Do you see why the Telecompressor yields so much unexpected reduction? Is the 121mm distance really computed from the Sharpley lens that is on the camera-side, or the one farther in the baffle of the telescope?
Also, If I want to use the Alan Gee telecompressor for Prime photography using Barlows / Eyepiece Projection, do I need to get additional adapters?
Thanks!
Wouldn’t the original Alan gee be much better fit for such configuration? Considering it sits inside the baffle and the stock visual back is used as the locking screw of it.
Also, using your 31/36 aspheric, wouldn’t using the original Alan gee allows to screw the eyepiece to the sct thread with the Alan gee In it’s place? And In general , which is more suitable for C8 with/without focal reducer, the 31 or the 36?
Thanks in advance
Celestron C11 (no edge)
2956233 Baader 2" ClickLock SCL (3.3")
2956100 Baader 2" ClickLock Diagonal Mirror
2956214 Baader 2" to 1¼" ClickLock Reducer (T-2 part #15B) with 31.5 Eyepieces
In the manual it seem need :
2408150 Baader 2" nosepiece to T-2 / M48 (T-2 part #16)
2958242 Baader Expansion Ring 2"a/T-2i with 1mm optical path length (T-2 part #28)
But it's not clear. Can you explain ?
Specifically, I have an AG I want to use again after a pause of a few years. It is currently in a 2" push-fitting without spacers which attaches the telescope to a Starlight AO unit, OAG, filterwheel and 694 CCD. The total from the back glass of the AG to the chip is about 129mm with the most compact connections I've found, or 8mm more than ideal.
I think for this reason, someone once told me to place the AG behind the AO and in front of the OAG/Filterwheel/CCD. However, this seems to me to be less than idea too. At the time, I ended up not using this set-up much in favour of the Hyperstar because the OTA was on a Fork-Wedge combination and quite wobbly. I have now deforked the OTA and put it on a decent EQ mount - so want to try this set-up again.
So my questions are: what is the best configuration? In the back of the optical tube inside the push-fitting with the 129mm to the chip or placed behind the AO and then at the "ideal" 121mm from that point? And what is the relation between the 146mm and 121mm?
Then my question is ¿wich is the best reducer to adapt to this combination ACF + APSC (3,76µ/px)?
Thank you.
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Additional Information
EAN Code | 4047825011572 |
---|---|
Manufacturer | Baader Planetarium |
SKU (#) | 2454400 |
Net weight (kg) | 0.09 |
Optical length (mm) | < 50 |
AR-Coating | Multi-Coated (MC) |
Optical Design | Field Flattener, Telecompressor |
compatible telescopes | Schmidt-Cassegrain |
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