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Primaluce Lab 0.6x Reducer-Field Flattener for AIRY ED APO Refractor Telescopes

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in In stock (2)
0.80 kg
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including VAT 20.00 % ( £27.00 )

By reducing the focal length of the telescope (for example, a 500mm focal length becomes 300mm), this 0.6x reducer/flattener increases the area framed by the camera sensor. In addition, decreasing the focal ratio of the telescope (for example AIRY APO80 f/6.25 becomes f/3.75), it allows you to record weaker details. Designed for photographic use with AIRY telescopes, it offer an extended correct field and it can be used with many different refractors.

Technical note: unscrewing the 2" nosepiece reveals a M54 thread. This might make it possible to attach it to certain field rotators, like Rigel Systems'.

Focal reducers are used in long-exposure astrophotography of deep-sky objects like nebulae, star clusters and galaxies, and in order to get the best images, it is important that the field of view framed by you camera to be flat (that is, the stars have point shape in all the field). Since reducing the focal length also the field is generally reduced, in this table you will find not only the focal length and focal ratio created by the use of the 0,6x reducer/flattener but also the size of the corrected field. This way you can check whether your camera sensor will be suitable for use in astrophotography (eg Atik 428EX CCD camera has 11mm diagonal sensor so it needs at least 11mm of flat field to have images with pinpoint stars in all over the field):

focal length
focal ratio
Focal length with
0.6x reducer/flattener
Focal ratio with
0.6x reducer/flattener

Flat field
diameter (mm) 

AIRY ED72 432mm  f/6   not available  N/A  N/A
AIRY APO80  500mm  f/6.25  300mm f/3.75   11mm
AIRY ED90 500mm  f/5.5  not available  N/A N/A
AIRY BLACK 90T  600mm f/6.7  360mm  f/4  14mm
AIRY ED100  600mm f/6   360mm  f/3.6  14mm
AIRY APO104T   650mm f/6.25   390mm f/3.75 11mm
AIRY APO120   900mm f/7.5   not available N/A   N/A
AIRY APO130T  860mm  f/6.6  not available N/A   N/A













The 0.6x reducer/flattener into 50.8mm connection of the focuser (in front it has a thread for connecting 50.8mm diameter filters). Rear (camera side) it has a T2 male thread and therefore it can be screwed directly onto the DSLR cameras ( using a T2 ring of the camera brand) or to a CCD camera (with T2 female thread).

Above image: 700Da camera connected to the AIRY ED100 refractor with reducer/flattener

This reducer/ flattener, in order to offer the best performance, requires that the camera sensor is positioned at 55mm distance from the reducer thread. This is precisely the distance provided by connecting the DSLR camera with T2 ring. For the use of CCD camera (that offer a sensor placed in more front position than the one of a DSLR camera) it is necessary to add a T2 extension. To calculate the required thickness, you can use the formula: required T2 extension = 55mm required distance - CCD camera back focus.

So, for example, if you use a QHY8L CCD camera that has 20 mm backfocus, the T2 you need will be: 55 - 20 = 35mm.

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