Application of a Rear-Mount DayStar Filter
DayStar Filters are designed to be mounted at the rear, eyepiece end of the telescope. This application allows flexibility to use the filter on many different kinds and sizes of telescopes. You are not aperture limited when using a DayStar Filter. Many DayStar owners use thier filters with apertures of 150mm or more with great success.

The important idea to understand when using a DayStar Filter is that light entering the filter must be as close to parallel as possible. That is to say that your focal ratio should be approximately F/30. F/ratios less than this allow light to enter the filter at different angles, increasing bandpass and reducing the contrast of the filter.

Owners can adapt different telescopes to the F/30 required by either introducing a barlow (negative lense) or by masking the objective and reducing the aperture as shown above.

Note for DayStar Filters ION owners:  The Ion is applied the same way the DayStar Quantum or ATM filters are. The ION Solar Filter series uses the same plate series that the Quantum series does.

An Energy Rejection Filter (or ERF) shown here in the off-axis configuration is used on SCT applications.  The ERF filter reduces the heat load coming into your telescope and the aperture reduction mask accomplishes the F/30 needed for Halpha.

Refractor users can choose from reduced aperture (as shown in the photo above) or full aperture ERF applications for a choice of low power/ resolution or high power/ resolution.


The T-Scanner and appropriate attached Powermate shown here are inserted directly into the eyepiece end of a telescope as-is. For easiest use full aperture, the Tele Vue Powermate lens is attached directly to the DayStar Filter using the convenient optional PMT adapter.  All Powermates may be applied this way. 2X, 2.5X, 4X and 5X.

The DayStar Quantum and Powermate shown here use the same Powermate and PMT adapter to attach directly to the DayStar Fiter.   The image at left also shows the application of a UV/IR Cut filter threaded on the front end of the Powermate.  This UV/IR cut filter can replace a front mount ERF on Achromat refractors as the reflective coating reflects heat load back out the front objective unfocused. This is NOT recommended for SCT applications or on APO telescopes.

The DayStar Quantum at left shows an optional GF2SCTT adapter.  A common SCT adapter used to connect the SCT thread to a T-thread in photography, this applies the Quantum easily to the eyepiece end an SCT like an LX200 or C-14, etc. The rear plate of the Quantum is also an SCT thread.  All SCT visual back adapters, diagonals and accessories mount directly to the Quantum SCT threaded rear plate.

The Daystar Quantum control which maintains and controls the filter's wavelength transmission uses native 12VDC power.  It may be powered off of a car, a battery, a solar panel or a Kendrick power pack. Even if the +/- terminals are crossed, the DayStar filter still works fine. Each DayStar Quantum comes with a 110/240AC power cord with a 6 foot extension and worldwide wall plug adapters.

CCD Camreas of many varieties can be used with a DayStar Filter. The image to the left shows the DayStar inserted in the eyepeice end of the telescope with a 4X powermate and PMT adapter installed.  On the rear of the DayStar is a GF2SCTT adapter which connects the CCD camera directly to the DayStar Quantum Filter. The clear exit aperture of all DayStar filters is a full 32mm or larger.

* HALF-BANDWIDTH: The term half-bandwidth refers to an optics industry standard of measure.  On a chart depicting the peak where light is transmitted, that peak's width is measured at the point 50% between zero and full transmission. This term is called half-bandwidth.

The Sun Today
Hydrogen Alpha Filters
Current Delivery Times:

4-6 weeks for:
Blocker and Trimmers
ION Filters
CaII H line filters
Quantum upgrade:  
Quantum SE Filters
SolaREDi 60 Scopes
SolaREDi 80 Scopes

3-6 months for:
Quantum PE Filters
Ca II K Line PE Filters
Sodium Line FIlters
Solar System Filter Wheel

All DayStar Hydrogen a filter assemblies need to be used in conjunction with a lens cover and Energy Rejection Filter.

Offering absolute precision control over wavelength transmission. . .

DayStar Filters LLC • 149 Northwest OO Highway • Warrensburg, MO 64093 - USA
Telephone: 866-680--6563 • service@daystarfilters.com • FAX: 1-866-791-0448