C11 --- (¿CFR?) --- BDS-SC --- (¿CRF?) --- ASI174
Second question: Is this advisable?
Thank You for any information that you may provide.
It's length is between 82 and 112 mm, the optimum back focus of the EdgeHD925 is 146,05mm from the end of the 3.3" thread. For photography, you should try to bring the camera into a position as close as possible to that distance. Visual use is less critical, although 2" star diagonals usually require about 11cm of optical length (prism diagonals need a little bit less).
We know of several users who use the SteelTrack and are satisfied. We just wouldn't recommend it in combination with the Celestron reducer, as it is designed for the specified distances to both telescope and camera.
My question is, will your UHC-S / L-Booster-Filter 2" fit internally in the BDS-SC/HD? If not, do you have another method to use the UHC-S filter with the setup mentioned above?
But you have two options:
- The Baader 2" nosepiece to T-2 / M48 (T-2 part #16) # 2408150 has got a thread for 2" filters
- The UFC filter drawer https://www.baader-planetarium.com/en/filters/universal-filter-changer.html is also compatible with the Diamond SteelTrack focuser. You can mount e.g. Diamond Steeltrack® M68 Adapter # 2957206 or Diamond Steeltrack® M48 Adapter # 2957204 at the SteelTrack and then configure a UFC filter drawer with M68 (for maximum aperture) or M48 connection on the telescope side and a T-2-thread on the camera side - or a wider connection for M48 or larger and one of our Wide T-rings to reduce vignetting of full-frame cameras as much as possible. A T-thread is smaller than a fullframe sensor, so that a Wide T-Ring is helpful with larger sensors.
El Enfocador Diamond Steeltrack® Baader BDS-SC de 2 ", es compatible con un Mac de 180 y un steeldrive II
If you Mak has got an 2" SC-thread (outer diameter 50,2mm), the SteelTrack should fit, it is an 2" 24 thread (60°) - you can find out about measuring a thread here:
Or you could use an adapter like 2"a / M48i Zero-length reducing piece (zero optical length) # 2454834 plus Diamond Steeltrack® M48 Adapter # 2957204 if you want to screw them together.
Please note that the reducer is farther away from its designed position if you use an additional focuser.
That adapter only fits the BDS-RT, not the BDS-SC.
Please note that you will potentially need an M90 extension, so that the focuser can reach its minimum focus position.
A user has explained the exact situation in his review:
Unforunately, we do not have a mounting plate with SC-thread, but you have two options:
1) Baader 2" Safety Kerf nosepiece with 2" filter thread # 2408156 equips the corrector with a 2"-nosepiece, so that you can use it like a 2" eyepiece.
2) 2"a / M48i Zero-length reducing piece (zero optical length) # 2454834
Diamond Steeltrack® M48 Adapter # 2957204
This option would be more sturdy and shorter, but the free aperture is a little bit smaller, so I wouldn't recommend it for very large sensor sizes.
The minimum height with optional S58 direct-thread adapters is 80 mm.
You can find the dimensions in this PDF: https://www.baader-planetarium.com/en/downloads/dl/file/id/29/product/2856/bds_sc_dimensions_technical_drawing.pdf
I see that this focuser has a min. height of 93mm but it is mentioned that this S58 adapter can be used to reduce the height to 80mm: https://www.baader-planetarium.com/en/baader-2%22-clicklock-eyepiece-clamps.html#574=936
My question is: can the focuser with the S58 adapter can fit on the 2"-24 (SC) male thread?
Eitherpoint it at the moon and put a piece of of paper behind it, so that you can see a sharp image - the distance between paper and telescope is the back focus. Or, if you already have a focuser, point it at the stars with either a camera attached or star diagonal and eyepiece, and measure the length of your focuser. Pleas note that eyepieces, DSLRs and astronomical cameras all have different optical lengths! A DSLR requires 55mm of backfocus, a CCD-camera often only about 1cm, and a 2" star diagonal about 11cm - so may work with an eyepiece and star diagonal without extensions, while a CCD-camera may require an extension.
The SC-version of the Steeltrack has got a focus travel of 30mm, so if you are switching between a 2" star diagonal and an astronomical CCD-camera, you will require an extension. The possible minimum heights are as follows
as supplied, incl. 2" clamp: 93 mm
with optional S58 direct-thread adapters: 80 mm
The RT-version for refractors may fit too, it has got a longer focus travel of 80mm and the following minimum lengths:
as supplied, incl. 2" clamp: 70 mm
with optional S58 direct-thread adapters: 59 mm
with optional S58-ClickLock clamp: 89 mm
You have to check the manual to see if one of the adapter threads matches your telescope, or if you need to manufacture a special adapter.
The SC version has got a shorter focus travel as you are more flexible with a Schmidt-Cassegrain and its moveable ain mirror than with a refractor telescope.
To remove this adapter, please refer to the manual on page 6:
For the RT-version (for refractors), we do have RT-Adapter M90x1 Diamond Steeltrack® (Skywatcher) # 2957283, but it does not fit on the SC-focuser.
The SC-focuser has got a length of 93mm plus 30mm of travel;
the RT-focuser has got a minimum length of 78mm plus 80mm of travel.
So, you can probably use the RT-version # 2957210 with the M90-adapter instead of the SC-version.
I also own a Diamond Steelrack SC which has a 2’’ 1.0 (metric) thread.
The threads are incompatible despite both being called SCT.
Do you sell an adapter from thread UNF24 to 1.0 ? otherwise what are my options ?
As you can see there is only 105mm back focus left. the BDS SC is at least 93mm long.
According to this circumstances there is unfortunately not enough back focus left to adapt
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Thanks for your understanding!
it is much easier to rotate the camera with a 2" nose piece even up to full format camera with wide T-ring and S52 barrel #2958551
Unfortunately, we do not know which thread is used on the CN212.
2) same question for Skywatcher MAK180
Thanks a lot !
The Sky-Watcher 180 *should* be equipped with a standard SC-thread (2), so you should be able to attach the BDS-SC without any problems - if the description I have found onlie (still) applies to your specific model; technical data can change over the years.
The Mak127 seems to have only a T-2-thread (and a clear aperture of 1,25"), so a 2"-focuser may be a bit over-sized. But you should be able to attach the focuser with the Baader Expansion Ring 2"a/T-2i with 1mm optical path length (T-2 part #28) #2958242. Please check the manual und Downloads for the dimensions the the steeltrack, to see if you get problems with the focussing knob of your telescope.
You can still use the main mirror focuser of your telescope when the SteelTrack is installed.
General Specifications for all Baader Diamond Steeltrack® (BDS) focusers:
- True diamonds form a micro-geared high precision drive system never accomplished before
- In comparison to conventional crayford or rack & pinion drives, this micro-geared movement has zero backlash, zero cogging, and zero flexure
- Diamond Steeltrack® 2" focusers lift a payload of 6kg (13 lbs) straight up, without slipping, without excessive bearing preload (bearing preload can be increased further if necessary)
- Bearing system utilizes unbreakable Instrument Grade Roller-Bearings instead of simpler Ball Bearings - handles higher loads with greater rigidity and accuracy. No Teflon-pads anywhere
- 1:10 Stainless Steel fine-focus mechanism, ready for attachment of the optional Diamond Steeldrive temperature-compensating motor drive system
- Detachable drive block assembly is reversible for right hand or left hand fine-focus operation and for attaching the Diamond Steeldrive motor block
- Shortest possible mechanical design achieves optimum balance between focuser height (backfocus) and rigidity requirements
- Zero shift locking knob to precisely stop any movement without affecting optical axis adjustment
- S58 Dovetail ring-clamp built into focusing tube for accepting optional T-2 / M48 / M68 and other S58 direct-thread adapters to enable direct thread connection of accessories and cameras without 2" clamp
- 2" eyepiece clamp with hardened bronze clamp ring (length of clamp: 12.5mm / ½") included as standard
- Optionally available 2" Baader Clicklock-clamp w. integrated S58 dovetail (added length: 16mm / 5/8")
- Two auxiliary threads (M60x1 and M55x0,75) cut into the RT & NT focusing-tube for attachment of dedicated field flatteners or focal reducers/correctors
- Each bearing individually adjustable for precise alignment of mechanical vs. optical axis
- Ultra-hard subzero coated bearing races – precision milled and much harder than anodizing or stainless steel
- Oversized 55mm inner clear diameter, to prevent vignetting, with anti-reflection knife-edge baffles
|Net weight (kg)||1.07|
|Focuser Travel||30 mm|
|Payload Capacity (kg)||6 kg|
|Inner Diameter / Clear Aperture (mm)||55|
|Shortest overall height (standard)||93 mm|
|Shortest overall height (w. opt. adapters)||80 mm|
|Motorized||No, but can be upgraded|
|Special Features||True diamonds form a micro-geared high precision drive system|
|Included Accessories||Includes adapter to fit all C14/C11/C9¼/C8/C6/C5 OTA’s|
|Inner Connection (lens sided)||Thread, 2" (50,8mm), 3,3", UNC|
|Inner Connection (eyepiece/-camera-sided)||Thread, Clamp, Dovetail ring clamp, M55, S58, 2" (50,8mm)|
|Optional Accessories||Baader Steeldrive temperature compensating motor drive system|
|Focuser size||2 inch|