Description
Rich Simons of Deep Sky Instruments and Optec have jointly developed a new, larger diameter standard spacer for large aperture telescopes. Like the Astro-Physics 2.7-inch spacer set, the Optec-DSI 3.5-inch spacers are available in a five different lengths.
The AP 2.7-inch thread has become an astronomy industry standard thanks to the tireless efforts of Roland and his team at Astro-Physics. Optec has produced a complementary extension set and a few new adapters in an effort to extend this industry standard. However, there are times when the 2.5″ clear aperture of the AP2.7 spacers will not allow enough light through clipping the edge rays.
Optec-DSI 3.5-inch extension tubes feature female threads on one end with male threads on the opposite end with knurled bases to help attach and detach these tubes. The extensions can be combined and stacked. We believe our four and five piece sets will provide all the needed extension for fixed focal length telescopes with 1/4″ (6.35mm) increments using a minimum number of pieces.
All extensions and mounts are made from high strength 6061 aluminum alloy and black anodized. Anti-reflection threading and internal baffles on the largest extension tube help minimize internal reflections. All internal surfaces are painted and baked with a non-reflecting ultra-flat black paint.
Specifications
- Spacer Lengths Available: 1/2″, 3/4″, 1″, 1-1/2″, and 3″
- Clear Aperture: 3.25″ (82.5mm)
- Back-focus Usage: Variable (see TABLE below)
Extension Tube Sets
|
Stock #19889 DSI 3.5 Extension Tube Set, 4-piece set
|
|
|
Stock #19890 DSI 3.5 Extension Tube Set, 5-piece set
|
|
Individual Extension Tubes and Retainers
|
Stock #19891 DSI 3.5 Extension – 1/2″ Length
|
|
|
Stock #19892 DSI 3.5 Extension – 3/4″ Length
|
|
|
Stock #19893 DSI 3.5 Extension – 1″ Length
|
|
|
Stock #19894 DSI 3.5 Extension – 1-1/2″ Length
|
|
|
Stock #19895 DSI 3.5 Extension – 3″ Length
|
|
|
Stock #19896 DSI 3.5x24tpi to AstroPhysics 2.7″ female Adapter
|
No Picture Available |
|
Stock #19897 DSI 3.5 Retaining Ring
|
|
|
Target Extension |
Spacers Required |
AP2.7 Spacer Stock Numbers |
DSI 3.5×24 Stock Numbers |
|
0.50” |
½” |
19882 |
19891 |
|
0.75” |
¾” |
19883 |
19892 |
|
1.00” |
1” |
19884 |
19893 |
|
1.25” |
½” + ¾” |
19882, 19883 |
19891, 19892 |
|
1.50” |
1-½” |
19885 |
19894 |
|
1.75” |
1” + ¾” |
19884, 19883 |
19893, 19892 |
|
2.00” |
1-½” + ½” |
19885, 19882 |
19894, 19891 |
|
2.25” |
1-½” + ¾” |
19885, 19883 |
19894, 19892 |
|
2.50” |
1-½” + 1” |
19885, 19884 |
19894, 19893 |
|
2.75” |
1-½” + ¾” + ½” |
19885, 19883, 19882 |
19894, 19892, 19891 |
|
3.00” |
3” |
19886 |
19895 |
|
3.25” |
1-½” + 1” + ¾” |
19885, 19884, 19883 |
19894, 19893, 19892 |
|
3.50” |
3” + ½” |
19886, 19882 |
19895, 19891 |
|
3.75” |
3” + ¾” |
19886, 19883 |
19895, 19892 |
|
4.00” |
3” + 1” |
19886, 19884 |
19895, 19893 |
|
4.25” |
3” + ¾” + ½” |
19886, 19883, 19882 |
19895, 19892, 19891 |
|
4.50” |
3” + 1-½” |
19886, 19885 |
19895, 19894 |
|
4.75” |
3” + 1” + ¾” |
19886, 19884, 19883 |
19895, 19893, 19892 |
|
5.00” |
3” + 1-½” + ½” |
19886, 19885, 19882 |
19895, 19894, 19891 |
|
5.25” |
3” + 1” + ¾” + ½” |
19886, 19885, 19883, 19882 |
19895, 19893, 19892, 19891 |
|
5.50” |
3” + 1-½” + 1” |
19886, 19885, 19884 |
19895, 19894, 19893 |
| Size | 19889, 19890, 19891, 19892, 19893, 19894, 19895, 19896, 19897 |
|---|
Fast Shipping and Professional Packaging
Due to our longstanding partnership with UPS FedEx DHL as well as other major international carriers, we are able to provide various shipping options. Our warehouse personnel will pack each item according to our strict requirements. Before they are shipped, your goods will be thoroughly examined and secured. Everyday, we send to thousands of clients in different countries. This is a sign of our determination to become the largest online retailer globally. The warehouses and centers for distribution are in Europe, as well as the USA.
Note that orders containing more than one item will be processed according to the specific item.
Before shipping before shipping, we'll inspect thoroughly the items you've purchased. Most orders are delivered within 48 hours. The estimated delivery time is between 3 and 7 days.
Returns
The inventory is always changing and we do not fully manage it because of the fact that many parties are involved, including our warehouse and factory. Therefore, the actual inventory could change at any time. It's possible that your order will be unable to fill when you have placed the order.
Our policy is valid for 30 days. If 30 days have gone without a trace since the purchase and we are unable to offer an exchange or refund.
In order for your item to be returned it must be in its original packaging, unopened and in the same condition as when you received it in. It must also be in its original packaging.
Related products
Filters
Solar Accessories
Eyepieces
Solar Accessories
Filters
Filters
Plates and Rings
Observing Aids
Observing Aids
Observing Aids
Filters
Filters
Filters
Observing Aids
Eyepieces
Astrophotography Accessories
Astrophotography Accessories
0.72x Quad Telecompressor Corrector for 155f7 EDFS Astro-Physics
Mount Accessories
Observing Aids
Filters