FREQUENTLY ASKED QUESTIONS 

 

Most of your questions will be answered here.  Please check the charts to see if the answer to your question is listed here before requesting further information from Draco Productions.
If you have questions not covered by the following most Frequently Asked Questions, please use the Feedback Form to post your question.  Other FAQ's may be added from time to time, dependent on responses from Feedback and letters to the Webmaster [ dracoproductions@hotmail.com ].

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Will the Erect Image Eyepiece fit my telescope?

What magnification will the Erect Image Eyepiece give my telescope?

What size Baader filter should I get for my refractor telescope?

What size Baader filter should I get for my reflector telescope?

What size Baader filter should I get for my Maksutov telescope?

Can Baader filters be used with my Dobsonian telescope?

If my reflector has an open-end back for ventilation, how will this affect my solar image?

What size Baader filter do I need if I want to use it with my binoculars?

How big a piece of Baader Solar Filter Material do I need to take a picture of the Sun?

 

 

 

 

 

 

Will the Erect Image Eyepiece fit my telescope?

The following is a list of telescope vendors and telescope models that will work with the EIE.  All refractors and Schmidt-Cassegrain telescopes will take the EIE.  Some Maksutov-Cassegrain telescopes will accommodate the eyepiece, and so will a limited number of reflectors.  EIE's are not suitable for Dobsonians or other telescopes that do not have short in-focusing rack-and-pinion focusers.

Astron
                90 mm f/5.6 Shortscope
                100 mm f/10 Equatorial   
                90 mm f/11 Equatorial

Astro-Phyisics
                105 mm Starfire EDF
                130 mm Starfire
                155 mm Starfire

Bushnell
                Compact 4.5" Reflector

Celestron
                Ultima Series
                Celestar Series
                Nextar Series (either Schmidt-Cassegrain or Refractor)
                CM 1100
                C102-HD 4" Refractor
                CR150 6" f/8 Refractor

Discovery Telescopes
                RFT-90 Refractor
                EQ Refractors

Edmund Scientific
                Astroscan

Jason
                All Refractors

Meade
                DS Series
                LX Series
                ETX 90 & ETX 125 ( see tutorial )

Orion
                Short Tube Telescope
                Skywatcher Telescope

Skygazer
                Skygazer 90 mm
                Skygazer 80 mm
                Equatorial Deluxe Reflector 4.5"

Takahashi
                BRC-250 10" f/5
                FSQ-106 N OTA 4: f/5
                FS-102 4: f/8 OTA
                CN-212

Tasco
                All Refractors

Tele-Vue
                All Refractors

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What magnification will the Erect Image Eyepiece give my telescope?

To find out what magnification you will get, divide your main objective's focal length (printed on the telescope tube or listed under specs) by the eyepiece focal length--in this case [the EIE], 10.5 mm.

So, for a 700 mm focal length refractor such as a typical 60 mm department store telescope, this eyepiece will yield about 67 power (67x) [700 divided by 10.5 = 67].  This is an excellent medium power eyepiece for observing the entire disc of the Moon, as it almost fills the entire field of view of the eyepiece.  Since many NASA and other maps of the Moon are erect image, this makes identifying Lunar features much easier than with ordinary inverted-image astronomical eyepieces.

For a conversion chart of the millimeters to inches in diameter of your main objective, please see the refractor and reflector Baader recommendations.

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What size Baader filter should I get for my refractor telescope?

The following are suggested sizes for various telescope main objectives.

Never use solar filters with an eyepiece, attached either in front of the eyepiece, or on the viewing portion.   The already magnified sunlight coming through the main objective may burn through the filter to your eye.  The correct placement of any solar filter material is in front of the main objective (large light-gathering lens at the front of the telescope or binoculars).

 

Refractor Telescopes
(filter is centrally mounted)

Baader Filter Size Main Objective in Millimeters Main Objective in Inches
 
1.5 " Filter 50 mm - 60 mm 2 - 2.4 inches
2" Filter 70 - 80 mm 3.25 inches
2.5" Filter 90 mm 3.5 inches
3" Filter 100 mm 4 inches
3.5" Filter 110 - 120 mm 4.25 - 4.5 inches
4" Filter 125 - 150 mm 5 - 6 inches
4.5" Filter 175 - 200 mm 7 - 8 inches
5" Filter 250 mm and up 12.5 inches and up

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What size Baader filter should I get for my reflector telescope?

The following are suggested sizes for various telescope main objectives.

Never use solar filters with an eyepiece, attached either in front of the eyepiece, or on the viewing portion.   The already magnified sunlight coming through the main objective may burn through the filter to your eye.  The correct placement of any solar filter material is in front of the main objective (large light-gathering lens at the front of the telescope or binoculars).


 Newtonian Reflector / Schmidt-Cassegrain Telescopes
(filter is mounted off-axis)

 

Baader Filter Size Main Objective in Millimeters Main Objective in Inches
 
1.5 " Filter 75 mm 3 inches
2" Filter 90 mm 3.75 inches
2.5" Filter 110 mm - 114 mm 4.25 - 4.5 inches
3" Filter 125 mm 5 inches
150 mm 6 inches
3.5" Filter 175 mm 7 inches
200 mm 8 inches
4" Filter 225 - 250 mm  9 - 10 inches
4.5" Filter 275 - 300 mm 11 - 12 inches
5" Filter 325 mm and up 12.5 inches and up

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What size Baader filter should I get for my Maksutov telescope?

The following are suggested sizes for various telescope main objectives.

Never use solar filters with an eyepiece, attached either in front of the eyepiece, or on the viewing portion.   The already magnified sunlight coming through the main objective may burn through the filter to your eye.  The correct placement of any solar filter material is in front of the main objective (large light-gathering lens at the front of the telescope or binoculars).

 

Maksutov Telescopes
(filter is mounted off-axis)

Maksutov Telescopes have long focal ratios, resulting in a dimmer image.
              Full aperture filters are recommended for use with most Mak telescopes.          

 

Maksutov Model

 Baader Size

 
ETX90 3.5" Filter
ETX105 4" Filter 
ETX125 4.5" Filter
6" - 7" Meade 5" Filter

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Can Baader filters be used with my Dobsonian telescope?

Dobsonian telescopes that are open frame instead of closed tube will have so much daylight spill-over that the image will be very low-contrast and quite unsatisfactory for the solar observer.  Even with cloth covers or vinyl tarps, there will possibly still be too much light.  Solid tube 'scopes are the only instruments that allow a bright, high-contrast solar image.

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If my reflector has an open-end back for ventilation, how will this affect my solar image?

If your reflector has an open-end vent in the back (most Newtonians do), you should make a cover for the back end that blocks all extraneous light that might enter.  This will give much better contrast and a darker background sky.  This is true for all solar filters.

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What size Baader filter do I need if I want to use it with my binoculars?

Baader filter material may be used over one binocular main objective, as long as the lens cap is kept in place over the other objective, or two pieces may be mounted to both objectives.
 
Never use solar filters with an eyepiece, attached either in front of the eyepiece, or on the viewing portion.   The already magnified sunlight coming through the main objective may burn through the filter to your eye.  The correct placement of any solar filter material is in front of the main objective (large light-gathering lens at the front of the telescope or binoculars).

Suggested use:

(2) 1.5" Baader sold as a pair for binoculars up to 80 mm.

(2) 2" Baader for 80 mm to 90 mm.  Use tripod mount for stability and cover other lens with lens cap.

3" Baader for 100 mm and up...the Super Giant binoculars, tripod-mounted with lens cap.

See also Small Binocular Baader Filters for 8 x 21 to 12 x 25 binoculars.

For most binocular observing with 50 - 80 mm binoculars in power ranges of 7x to 20x, the 1.5" filters mounted in front of the main objective will be sufficient.  One method of mounting is to cut a 1.5" hole in your dust cover.  The other recommended method is to make a cell that fits over your binocular main objective  (see End Cap and End Cap 2 illustrations for construction suggestions).  This makes your binoculars an ideal optical instrument for eclipse viewing, and casual sunspot observation.  A surprising amount of sunspot activity and detail will be visible.  Note:  for hand-held observation, binoculars of 7x to 10x are a lot easier to use than higher power models which will require tripod mounting.  With tripod mounts, you lose the simple sky scanning- sweeping abilities that you have with hand-held binoculars.  Remember that with the Baader filter in place, the only thing that you can observe is the sun.  

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How big a piece of Baader Solar Filter Material do I need to take a picture of the Sun?

The 1" piece of Baader filter material on the Baader Solar Viewer card is readily adapted for 35 mm cameras.

For use with a telephoto lens, a 1.5" piece of Baader is recommended.

A 2" piece of Baader is sufficient for commercial television cameras, and produces impressive images that may be aired along with TV coverage of the solar event.

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