Blue Fireball M51x0.75 Male Thread to M42x0.75 T/T2 Male Thread Adapter: For Some Celestron, Orion & Sky-Watcher 9x50 Finders
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This adapter has a male M51x0.75 on one side and a male T / T2 thread (M42x0.75) on the other side. Many (but not all) 9x50mm straight-through finders made by Celestron, Orion Telescopes, and Sky Watcher use a female M51x0.75 thread on the rear of the tube. You can therefore use this adapter to convert such a finder into a guidescope with standard M42 T threads which can be attached directly to many popular guide cameras.
Zero-optical length, very low profile version. Due to this, the adapter does not feature a gripping ring and you may need a spanner wrench or other tool to thread or unthread this adapter using the 2 notches provided for this purpose.
Might also work with some right angle finders, although you will need an additional T-thread spacer to reach focus in the straight-through mode. This adapter is known to fit the current # 93781 Celestron right angle finder.
While this should work with most current 50mm finders from Celestron, Orion, and Sky-Watcher, we cannot guarantee this due to manufacturing variations in the finders. Clean the fine finder threads carefully before attempting to attach this adapter as the finder threads often have embedded fine metal, plastic or paint particles.
Specifications:
- Total thickness = 10mm (0.39")
- Optical length (assuming both male threads at either end are fully threaded all the way in) = 0mm (0.0")
- Male M51x0.75 thread length = 5mm (0.20")
- Male T thread length = 5mm (0.20")
- Male T thread specification = M42x0.75
- Weight = 0.5oz
- Precision CNC-machined from black anodized aluminum
Blue Fireball part number: T-19
Other Information
- Country of Manufacture: China
This adapter has a male M51x0.75 on one side and a male T / T2 thread (M42x0.75) on the other side. Many (but not all) 9x50mm straight-through finders made by Celestron, Orion Telescopes, and Sky Watcher use a female M51x0.75 thread on the rear of the tube. You can therefore use this adapter to convert such a finder into a guidescope with standard M42 T threads which can be attached directly to many popular guide cameras.
Zero-optical length, very low profile version. Due to this, the adapter does not feature a gripping ring and you may need a spanner wrench or other tool to thread or unthread this adapter using the 2 notches provided for this purpose.
Might also work with some right angle finders, although you will need an additional T-thread spacer to reach focus in the straight-through mode. This adapter is known to fit the current # 93781 Celestron right angle finder.
While this should work with most current 50mm finders from Celestron, Orion, and Sky-Watcher, we cannot guarantee this due to manufacturing variations in the finders. Clean the fine finder threads carefully before attempting to attach this adapter as the finder threads often have embedded fine metal, plastic or paint particles.
Specifications:
- Total thickness = 10mm (0.39")
- Optical length (assuming both male threads at either end are fully threaded all the way in) = 0mm (0.0")
- Male M51x0.75 thread length = 5mm (0.20")
- Male T thread length = 5mm (0.20")
- Male T thread specification = M42x0.75
- Weight = 0.5oz
- Precision CNC-machined from black anodized aluminum
Blue Fireball part number: T-19
This adapter has a male M51x0.75 on one side and a male T / T2 thread (M42x0.75) on the other side. Many (but not all) 9x50mm straight-through finders made by Celestron, Orion Telescopes, and Sky Watcher use a female M51x0.75 thread on the rear of the tube. You can therefore use this adapter to convert such a finder into a guidescope with standard M42 T threads which can be attached directly to many popular guide cameras.
Zero-optical length, very low profile version. Due to this, the adapter does not feature a gripping ring and you may need a spanner wrench or other tool to thread or unthread this adapter using the 2 notches provided for this purpose.
Might also work with some right angle finders, although you will need an additional T-thread spacer to reach focus in the straight-through mode. This adapter is known to fit the current # 93781 Celestron right angle finder.
While this should work with most current 50mm finders from Celestron, Orion, and Sky-Watcher, we cannot guarantee this due to manufacturing variations in the finders. Clean the fine finder threads carefully before attempting to attach this adapter as the finder threads often have embedded fine metal, plastic or paint particles.
Specifications:
- Total thickness = 10mm (0.39")
- Optical length (assuming both male threads at either end are fully threaded all the way in) = 0mm (0.0")
- Male M51x0.75 thread length = 5mm (0.20")
- Male T thread length = 5mm (0.20")
- Male T thread specification = M42x0.75
- Weight = 0.5oz
- Precision CNC-machined from black anodized aluminum
Blue Fireball part number: T-19
Other Information
- Country of Manufacture: China
| Product Status | new |
|---|---|
| Free Shipping Graphic | Free US Shipping |
| Hide Found a better Shipped Price on Frontend? | No |
Blue Fireball M51x0.75 Male Thread to M42x0.75 T/T2 Male Thread Adapter: For Some Celestron, Orion & Sky-Watcher 9x50 Finders


















