BRESSER 9621801 Space Explorer 90-900 EQ Refracting Telescope Instruction Manual

June 5, 2024
BRESSER

BRESSER 9621801 Space Explorer 90-900 EQ Refracting Telescope

BRESSER 9621801 Space Explorer 90-900 EQ Refracting
Telescope

Possible observation objects

BRESSER 9621801 Space Explorer 90-900 EQ Refracting Telescope fig
4

General Information

About this instruction manual
Please read the safety instructions in this manual carefully. Use this product only as described in the manual to avoid damage to the device or injury. Keep the operating instructions in a safe place so that you can always keep up to date on all the operating functions.

Designated use
This device is for personal use only.
It was developed for a magnified representation of observations of nature.

General warnings

  • RISK OF BLINDNESS!
    Never look directly at, or near to the sun with this device. There is a RISK OF BLINDNESS!

  • DANGER OF SUFFOCATION!
    Children must only use the device under adult supervision. Keep packaging materials (plastic bags, rubber bands, etc.) away from child-ren! There is a DANGER OF CHOKING!

  • FIRE HAZARD!
    Do not expose this device – especially the lenses – to direct sunlight! Focusing of sunlight could cause fires.

  • ATTENTION!
    Do not disassemble the device! In the event of a defect, please contact your dealer. They will contact the Service Centre and can arrange the return of this device for repair if necessary.
    Do not expose the device to high temperatures.

Protect privacy!
The device is only intended for private use. Respect the privacy of your fellow human beings – do not look into private flats with this device, for example!

All parts

BRESSER 9621801 Space Explorer 90-900 EQ Refracting Telescope fig
1

  1. Telescope tube
  2. LED viewfinder
  3. Adjustment screws
  4. Tube opening
  5. Objective
  6. Eyepiece socket
  7. Focus wheel (focus adjustment)
  8. Tube clamp
  9. Mounting
  10. Accessory tray with screws (3x) and wing nuts (3x)
  11. Locking screws (tripod)
  12. Dust cap
  13. Tripod Leg
  14.  Flexible shaft for declination adjustment
  15. Flexible shaft for right ascension adjustment
  16. Fastening struts
  17. Counterweight + rod
  18.  Eyepiece
  19.  Upright Prism
  20. Barlow Lens

PARTS

  • BRESSER 9621801 Space Explorer 90-900 EQ Refracting Telescope fig 2 A Tube clamp
  • B Focusing the focus wheel
  • C Scale of the declination axis
  • D Declination axis fixing screw
  • Fine adjustment of the declination axis
  • F Latitude setting scale
  • G Fixing and adjusting screw of the latitude setting
  • H Counterweight with locking screw
  • I Fixing screw of the right ascension axis
  • J Right ascension axis scale
  • K Fine-adjustment of the right ascension axis
  • L Fixing screw for horizontal alignment
  • M Bracket for optional tracking motor
  • N Clutch for disengaging the engine
  • O Transmission gear for tracking motor

Part I – The Structure

  1. General information about the structure and the choice of location
    Before you begin the assembly, you must choose a suitable location for your telescope. It helps if you set up this instrument in a location where a clear view of the skies, a stable footing, and sufficient space around you are given.
    First, remove all the parts from the packaging. Using the diagram, check whether all the parts are included.

  2. Set up the tripod
    The tripod legs are pre-assembled and already connected to the tripod head (Fig 5, X) and the tripod spider (Fig 1, 16).
    Remove the tripod from its packaging and place it vertically with the tripod feet facing down. Now take two of the tripod legs and carefully pull these tripod legs apart to the fully open position. The entire weight of the tripod rests on one leg.
    Then set up the tripod straight. Now pull out each tripod leg individually to the desired length (Fig 4) and now turn one each of the clamping screws (Fig 4, 11) 3 pieces hand-tight. Do not overtighten the screws! The clamping screws are used to lock the inner tripod leg segments at the desired height.

  3. Insert mount
    Next, attach the mount (Fig 1, 9) to the tripod head (Fig 5, X). To do this, insert the mount in to the top of the tripod head and hand-tighten the thumbscrew from below.
    The mount (Fig 1, 9) is assembled by sliding the weight on to the weight rod (Fig 7, X) and screwing it firmly in to the thread of the mount from below.
    The mount is completed by placing the tube clamp (Fig 1+3, 8) on the mount and securing it with the screw (Fig 8, X).
    Maksutov optics do not have a tube clamp. The rail is placed directly on to the mount.

  4. Mount she lf
    The accessory tray (10) is mounted to the mounting struts with the beveled sides facing down. To do this, the screws (Fig 6, X) are pushed through the holes in the tray and the brackets from above and screwed on with the wing nuts (Fig 6, Y) from below.

  5. Mounting the tube
    To mount the telescopic tube (Fig 1, 1), first loosen the screws of the tube clamps (Fig 9, X) on the holder and open the clamps.
    Place the tube in the middle of the holder and close the clamps.
    Hand-tighten the clamp screws again so that the tube is securely fastened to the holder.

  6. Insert eyepiece and upright prism
    Three eyepieces (Fig 2, 18) and an upright prism (Fig 2, 19) are supplied with your telescope as basic equipment.
    With the eyepieces you determine the respective magnification of your telescope. Before inserting the eyepieces and the upright prism, remove the dust cap from the eyepiece tube.
    (Fig 1, 6) Loosen the clamping screw (Fig 12, X) on the eyepiece tube and insert the upright prism first. Then retighten the clamping screw (Fig 12, X).
    Then fix the 20mm eyepiece in the upright prism in the same way by opening and closing the clamping screw (Fig 13a, X).
    Make sure that the eyepiece sight points vertically upwards. This facilitates easy viewing. Otherwise, loosen the clamping screw (Fig 12, X) on the eyepiece tube and turn the upright prism to this position.

  7. Mounting and adjusting the LED viewfinder
    Fully insert the base of the LED viewfinder (Fig 1a, 2) into the corresponding base on the optics tube (Fig 10, X).
    IMPORTANT: Make sure that the mirror surface of the LED viewfinder points towards the tube opening when attaching it.

  8. Adjusting the LED viewfinder
    The LED viewfinder must be adjusted before use. This means that the “viewing direction” of the LED viewfinder and the optical tube must be matched:
    Insert the eyepiece with the longest focal length in to the zenith mirror (13). Aim the telescope at a prominent object at a distance of approx. 300 m (e.g. house gable, church spire, etc.) until it appears in the centre of the field of view (Fig14, A).
    Turn on the LED viewfinder. To do this, move the slider (Fig 1a, Z) to position ‘1’ (weak red dot) or ‘2’ (brighter red dot).
    Look through the LED viewfinder and adjust it by turning the horizontal (Fig 1a, Y) and vertical (Fig 1a, Z) adjustment screws so that you see the red dot in the center of the image (Fig14, C). The LED viewfinder and telescope are now matched.
    Important: The image in the telescope will be upside down unless you use appropriate accessories to invert the image (e.g. zenith prism).

  9. Use protective caps
    To protect the inside of your telescope from dust and dirt, the tube opening is protected by a dust cap (Fig 11, X). There is also a dust cap on the eyepiece tube (Fig 1, 6).

  10. Use flexible shafts
    The flexible shafts facilitate the exact fine adjustment of the declination and right ascension axis. They are pushed onto the holders provided for the two axles (Fig13, Y) and fixed with the small clamping screws (Fig 13, X).
    Note: The long flexible shaft (Fig 1, 14) is mounted parallel to the telescopic tube. The fastening is done with a clamping screw at the provided notch of the axle. The short flexible shaft (Fig 1, 15) is fitted laterally. The fastening is done with a clamping screw at the provided notch of the axle.

The handling

BRESSER 9621801 Space Explorer 90-900 EQ Refracting Telescope fig
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  1. Function and use of the mount
    The following information is extremely important for the positioning and tracking accuracy of your telescope during a night observation.
    Your telescope has a so-called “parallactic mount” (also equatorial mount). This is characterized by two axes that can be rotated perpendicular to each other (Fig15, a+b)
    The so-called right ascension axis (also RA or hour axis) (Fig 15, b) must be aligned parallel to the polar axis of the earth (Fig 25, c). For the correct setting of the pole height, see Part II – 4. Handling – Adjusting the telescope).
    The declination axis (also DEC or elevation axis) (Fig15, a) is used to set the altitude of a celestial object in relation to the celestial equator (Fig 25, d). To do this, take the declination coordinates of a celestial object from a star chart or discover the objects yourself.
    With the manual operation of the right ascension axis via the flexible shaft (Fig 1, 15) you continuously compensate for the earth’s rotation in the opposite direction.
    This way, your selected (= positioned) object always remains in the field of view of the eyepiece.

  2. Choosing the right site
    A dark location is very important for many observations since disturbing lights (lamps, lanterns) can considerably impair the sharpness of detail of the telescope image.
    When you go outdoors at night from a bright room, your eyes have to get used to the darkness. After about 20 minutes you can start your astro observation.
    Do not observe from closed rooms and place your telescope with the accessories in its location approx. 30 min. before starting observation to ensure temperature equalization in the tube.
    Furthermore, you should make sure that this telescope is placed on a level, stable surface.

  3. Balancing the telescope
    Your telescope must be balanced before observing. That is, the declination axis and the right ascension axis are adjusted for smooth and accurate operation.
    The right ascension axis is balanced by loosening the fixing screw (Fig15, I) and tilting the weight rod to a horizontal position. Now move the counterweight (Fig15, H) on the rod until the tube and the counterweight remains in this horizontal position. Retighten the fixing screw (Fig15, I) of the right ascension axis. The declination axis is balanced by loosening the fixing screw (Fig15, D) of the declination axis. Then loosen the screws of the tube holder (Fig15, A) and move the tube until it also remains in a horizontal position. Do not forget to re-tighten the screws of the tube holder and the fixing screw of the declination axis.

  4. Adjusting the telescope
    Adjust the latitude axis (Fig15, F) (pole height) by loosening the fixing screw (Fig17, X) and adjusting the Pohl height accordingly with the adjusting screw (Fig 17, Y).
    The number on which you set the axis depends on the latitude of your location (e.g. Munich 48°, Hamburg 53°).
    Do not forget to tighten the fixing screw again. Then adjust the declination axis (Fig15, C) to 90° by loosening and tightening the fixing screw (Fig15, D). The
    telescope tube is now aligned parallel to the Earth’s axis. This is called polar alignment.

  5. Polar alignment of the telescope
    Point the telescope with the tube opening forward towards the north. To do this, loosen the locking screw (Fig 18). Now you can rotate the telescope tube and align it exactly to the north. If necessary, use a compass to help you. Afterward, the locking screw is fixed again.
    Check that your telescope is set up as shown in Fig 27. The counterweight (Fig 27, X) points to the ground and thus forms a vertical axis together with the tube.
    In this position you can see the polar region with the polar star through the viewfinder. Polaris is the brightest object in this region. (Fig 26)
    This should then also be visible in the center of the field of view of the eyepiece (f=20 mm). Polar alignment has been achieved. This setup requires some patience, but rewards you with a good positioning option when searching with celestial coordinates.
    In this polar alignment, the graduated circles (scales) of the declination axis (Fig 28) should be at “9” (= 90°) and the right ascension axis (Fig 29) at “0” (= 0 hours). If necessary, carefully rotate both scales to the appropriate values (aligned with the arrows in each case).
    Thus set, you can use the finding of celestial objects with the help of the graduated circles (scales) (see also 3.1. Possible objects of observation).

  6. Fine alignment by means of LED viewfinder
    Your telescope is now roughly aligned and adjusted.
    To achieve a comfortable observation position, carefully loosen the screws of the tube holder (Fig 9, X) so that you can rotate the telescope tube. Move the eyepiece and LED viewfinder to a position from which you can observe comfortably.
    The fine alignment is done by using the finder scope. Look through the viewfinder and try to align the polar star (Fig 26) with the illuminated point (Fig 14). The shaft (Fig15, K) of the hour axis (Fig15, b), as well as the shaft (Fig15, E) of the declination axis (Fig15, a) will help you with the exact setting.

  7. First observations
    Remove the caps from the openings for observation.
    After you have adjusted the polar star in the LED viewfinder, you will be able to see the polar star in the telescope when you now look through the eyepiece.
    If necessary, you can now align the star more precisely with the aid of the flexible shafts and adjust the focus using the focus wheel (7).
    Furthermore, you can now set a higher magnification by changing the eyepiece (smaller focal length). Please note that the magnification of the stars is hardly or not at all perceptible.

  8. Star search
    At first, you will certainly find it difficult to orientate yourself in the starry sky, as stars and constellations are always in motion and change their position in the sky depending on the season, date and time. The exception is the polar star. Through it runs the extended imaginary polar axis of the earth. It is a fixed star and the starting point of all-star charts. On the drawing, you can see some well-known constellations and star arrangements that are visible all year round. However, the arrangement of the stars depends on the
    date and time. If you point your telescope at one of these stars, you will notice that it disappears from the field of view of your eyepiece after a short time. To compensate for this effect, operate the flexible shaft (Fig15, K) of the right ascension axis and your telescope will follow the apparent trajectory of this star.

  9. Setting circles
    Stars and other heavenly bodies are positioned in the heavens by coordinates. A star’s place in the universe is determined by its right ascension and declination.
    Declination (Fig 22, C) is the distance of a star from the celestial equator (Fig 25, d), measured in angular degrees. For stars north of the celestial equator, the degree becomes positive. If the star is south of the equator, the degree is marked with a minus sign.
    Right ascension (Fig 22, J) is a distance of a star from the vernal equinox measured on the celestial equator. The vernal equinox is the point of intersection of the celestial equator with the apparent orbit of the sun (the so-called Ecliptic) (Fig 25,e). This happens in spring at the equinox (end of March). The value is counted in time from 0 to 24 o’clock, contrary to the daily celestial revolution. You can find more detailed information in star charts or the relevant specialist literature.

  10. Accessories
    Several accessories (Fig 2) are supplied with your telescope as standard.
    Important: When fitting accessories, ensure that the small clamping screws (Fig 12, X) for fixing are always hand-tightened.

  11. Eyepieces
    By changing the eyepieces, you determine the respective magnification of your telescope.
    Calculation of the magnification:
    Focal length (telescope) ÷ Focal length (eyepiece) = Magnification

  12. Diagonal mirror
    When looking through the eyepiece, an upside-down image appears for technical reasons. The zenith mirror causes an image inversion and is therefore especially suitable for earth observation. But it is also very helpful for easier orientation in the starry sky.

  13. Barlow Lenses
    With a 3x Barlow lens, you can achieve an additional increase in magnification of 3x.
    If necessary, the Barlow lens (Fig 23, 20) is inserted between the upright prism (Fig 23, 19) and the eyepiece (Fig 23, 18).
    Note: Not every mathematically possible enlargement (sh. Table to 10.1) is also absolutely sensible. Some objects – especially in the night sky – can only be seen blurred at higher magnifications. This is not a defect, but a technical or physical one.

  14. Dismantling
    After a hopefully interesting and successful observation, it is recommended to store the entire telescope in a dry and well-ventilated room. Some telescope models allow you to separate the mount and tripod by simply unscrewing them. In this case, your settings on the mount are retained. Do not forget to put the dust-protection caps onto the OTA opening and onto the eyepiece connection. Also, you should stow all the eyepieces and optical accessories in their corresponding containers.

  15. Cleaning & Storage
    Clean the lenses (eyepieces and/or objective lenses) only with a soft and lint-free cloth (e.g. microfibre cloth). To avoid scratching the lenses, use only gentle pressure with the cleaning cloth.
    To remove more stubborn dirt, moisten the cleaning cloth with an eyeglass cleaning solution and wipe the lenses gently.
    Protect the device from dust and moisture! After use, particularly in high humidity, let the device acclimatize at room temperature for a short period of time, so that the residual moisture can dissipate.

Troubleshooting

  • Mistakes: Solution:
  • No image Remove dust cap from tube opening Select eyepiece with lower magnification (= higher focal length)
  • Blurred picture Focusing with the focus wheel No focusing possible Wait for temperature equalization (approx. 30 minutes)
  • Bad picture Never watch through a pane of glass Observation object in the viewfinder, but not visible through the eyepiece Adjust the viewfinder (see Part I – 8.)
  • Difficult tracking of the axes via shafts Balance telescope and counterweight (sh. Part II – 3.)
  • Despite upright prism only “crooked” image Align upright prism vertically in the eyepiece tube.

Disposal

Dispose of the packaging materials by type. Contact your local waste disposal service or environmental authority for information about the proper disposal.
Observe the current legal regulations when disposing of the device!
Information on proper disposal can be obtained from municipal waste disposal service providers or the Environmental Agency.
Do not dispose of electronic devices in the household waste!
According to the European Directive 2002/96/EC on Waste Electrical and Electronic Equipment and its transposition into national law, used electrical equipment must be collected separately and recycled in an environmentally sound manner.
Batteries and rechargeable batteries must not be disposed of with household waste. You are legally obliged to return used batteries and accumulators and can return the batteries after use either at our sales outlet or in the immediate vicinity (e.g. in the trade or in municipal collection points) free of charge.
Batteries and accumulators are marked with a crossed-out dustbin and the chemical symbol of the pollutant, “Cd” stands for cadmium, “Hg” stands for mercury and “Pb” stands for lead.

Warranty & Service

The regular warranty period is 5 years and begins on the day of purchase. For complete warranty terms and services, please visit www.bresser.de/warranty_terms.
In the event of a warranty claim, please first contact the service team responsible for your country, preferably by e-mail or using the contact form on the website.
Here you can be helped quickly in most cases. The corresponding contact information can be found under “Service” in this manual.

IMPORTANT!
Do not send in devices – even in the event of damage – without first consulting the service department. Unfortunately, unsolicited devices cannot be accepted and processed.

Please contact the service center first for any questions regarding the product or claims, preferably by e-mail.
E-Mail: service@bresseruk.com
Telephone: +44 1342 837 098
BRESSER UK Ltd.
Suite 3G, Eden House Enterprise Way
Edenbridge, Kent TN8 6HF United Kingdom
Number charged at local rates in the UK (the amount you will be charged per phone call will depend on the tariff of your phone provider); calls from abroad will involve higher costs.

References

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