illuminated ep's ?

[omegacrux]

Can someone explain what there for, I've seen them but don't know what use they are ?

[traveller]

As far as I know, they are useful in centering the object and assist in drift alignment, which is critical in astrophotography work to minims field rotation.
HTH.
Bo

[allan gould]

It's for those that use their telescopes at a very dark site that wish to simulate light pollution!

Seriously, it's as Bo said above

[ausastronomer]

Hi David,

As has been stated above.

In addition, some people also use them for visual observing to "perfectly" center their target when they align their Digital Setting Circles and Digital Telescope Computers like the Argo Navis. However, this IMO is not necessary for a high quality alignment for visual astronomy.

You can also take an illuminated reticle eyepiece to the next level, which is an astrometric eyepiece. This is an illuminated eyepiece with internal scales etched on glass for taking angular size measurements of astronomical features like double stars, moon craters and planetary features. You can also use them to measure the size of DSO's and their features.

Cheers,
John B

[omegacrux]

Thanks for that , yeah I was thinking why would you want an ep that glows at you ! Thanks

[CDKPhil]

Hi David,

I was using an illuminated reticle last night.
I use it to do calibration runs for my Paramount MX mount.
The illuminated cross hairs make it very easy to centre stars. You do not need to strain your eyes looking for a dark cross hair. Mine has an adjustable brightness. It is a small LED that runs off batteries, it screws into the side of the eye piece. The cross hairs are etched in glass, and the light from the LED follows the etched lines.

I will only use this eyepiece for visual observations. If I was taking photos, I would use a camera to do the alignment / calibration.

Another use would be in a finder scope.

Cheers
Phil

[Paddy]

I use one for estimating object size in visual observing, but having found that the light is too bright even at lowest power, I shine a dim red light on the secondary to show up the markings without drowning the object.

[omegacrux]

Thanks Patrick
Yeah I was wondering how bright they are I don't think I need one ,yet !

[Harpspitfire]

i dont see it mentioned yet, but i used to use mine for manual guiding befor auto guiding became affordable

[Shano592]

For all those interested, I will probably be bringing some more into the country in a couple of months.

From memory, they were going for around $45 shipped. Someone can correct me if I am off track (no pun intended).

I'll keep you all posted, and if it happens, I will list them for sale in the Eyepiece section in IceTrades.