Spectrum Telescope Glass Solar Filter: 4.25" Cell Inside Diameter
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Spectrum Telescope glass solar filter mounted in a 4.25" inside diameter cell # ST425G.
1. Selecting the Correct Solar Filter for your Telescope
This solar filter is designed to be fitted on the front (sky-end) of your telescope, spotting scope, or camera lens. The filter slides over the front of the tube and is locked down in place with the included thumbscrew(s).
This filter cell has an inside diameter of approx. 4.25" and has a clear filter aperture of 3.14" (80mm). It is meant to fit on tubes with an outside diameter between 3-7/8" (98mm) to 4-1/8" (105mm).
This filter is known to fit the following items:
- Meade ETX 90
- Celestron: NexStar 60/80/80GT, FirstScope 90EQ
- Orion StarMax 90, Apex 90
- StellarVue NightHawk APLANAT, NightHawk Next Generation (with dew shield), SV809D (with dew shield)
- Questar 3.5
- Williams Optics ZS80 II ED, Megrez 80
- Vixen A80MF Refractor
- Others? Let us know!
However, we very strongly recommend that you buy this filter only after measuring your tube size carefully (as explained below), even if your telescope is mentioned in the list above.
To get the proper fit, measure the outside diameter very carefully by using a caliper, ruler, or tape measure. See the 4th product photo above. Measure the widest distance of the telescope tube starting from the exterior of the casing, across the center and to the exterior part of the casing on the other side. After you have your measurements, you should order a size slightly larger than what you measured. This is because your measurement is being compared with the solar filter ID (inside diameter). For instance, if you measure 4" across the outside of the tube end, you should order a 4.25" inside diameter size solar filter. This will make it just a little bigger than the measurement you took.
Also, for example, If you have a 4" telescope, do not buy a 4" solar filter! Telescope aperture is not the same as telescope tube size. The telescope tube diameter will always be slightly larger than the telescope aperture. Measure it carefully before ordering to avoid disappointment and expensive returns.
2. Filter Substrate and Cell Details
This full aperture glass solar filter allows only a safe amount of light to pass through your telescope, spotting scope, etc. for solar viewing or imaging. It is an ND 5 filter and therefore blocks 99.999% of the Sun's visible light. It is made from hand-selected glass that is of high quality and coated with a thoroughly inspected reflective coating. The image of the sun viewed through this glass solar filter has a yellowish-orange natural look when directly viewed through a telescope or if photographed.
The glass filter is mounted in an aluminum cell that can be securely attached to the telescope tube with the included nylon thumb screw(s). This filter comes packaged in a foam-lined shipping/storage box. Instructions for storage and care are also included.
3. Warning
Never look at the sun without special eye protection. When viewing the Sun, use this filter in front of your optical instrument at all times when any part of the Sun is visible.
| Free Shipping Graphic | Free US Shipping |
|---|---|
| Hide Found a better Shipped Price on Frontend? | No |
Spectrum Telescope glass solar filter mounted in a 4.25" inside diameter cell # ST425G.
1. Selecting the Correct Solar Filter for your Telescope
This solar filter is designed to be fitted on the front (sky-end) of your telescope, spotting scope, or camera lens. The filter slides over the front of the tube and is locked down in place with the included thumbscrew(s).
This filter cell has an inside diameter of approx. 4.25" and has a clear filter aperture of 3.14" (80mm). It is meant to fit on tubes with an outside diameter between 3-7/8" (98mm) to 4-1/8" (105mm).
This filter is known to fit the following items:
- Meade ETX 90
- Celestron: NexStar 60/80/80GT, FirstScope 90EQ
- Orion StarMax 90, Apex 90
- StellarVue NightHawk APLANAT, NightHawk Next Generation (with dew shield), SV809D (with dew shield)
- Questar 3.5
- Williams Optics ZS80 II ED, Megrez 80
- Vixen A80MF Refractor
- Others? Let us know!
However, we very strongly recommend that you buy this filter only after measuring your tube size carefully (as explained below), even if your telescope is mentioned in the list above.
To get the proper fit, measure the outside diameter very carefully by using a caliper, ruler, or tape measure. See the 4th product photo above. Measure the widest distance of the telescope tube starting from the exterior of the casing, across the center and to the exterior part of the casing on the other side. After you have your measurements, you should order a size slightly larger than what you measured. This is because your measurement is being compared with the solar filter ID (inside diameter). For instance, if you measure 4" across the outside of the tube end, you should order a 4.25" inside diameter size solar filter. This will make it just a little bigger than the measurement you took.
Also, for example, If you have a 4" telescope, do not buy a 4" solar filter! Telescope aperture is not the same as telescope tube size. The telescope tube diameter will always be slightly larger than the telescope aperture. Measure it carefully before ordering to avoid disappointment and expensive returns.
2. Filter Substrate and Cell Details
This full aperture glass solar filter allows only a safe amount of light to pass through your telescope, spotting scope, etc. for solar viewing or imaging. It is an ND 5 filter and therefore blocks 99.999% of the Sun's visible light. It is made from hand-selected glass that is of high quality and coated with a thoroughly inspected reflective coating. The image of the sun viewed through this glass solar filter has a yellowish-orange natural look when directly viewed through a telescope or if photographed.
The glass filter is mounted in an aluminum cell that can be securely attached to the telescope tube with the included nylon thumb screw(s). This filter comes packaged in a foam-lined shipping/storage box. Instructions for storage and care are also included.
3. Warning
Never look at the sun without special eye protection. When viewing the Sun, use this filter in front of your optical instrument at all times when any part of the Sun is visible.
| Free Shipping Graphic | Free US Shipping |
|---|---|
| Hide Found a better Shipped Price on Frontend? | No |
Spectrum Telescope Glass Solar Filter: 4.25" Cell Inside Diameter # ST425G