Reticule Eyepieces - Illuminated or not

[BargeGazer]

I am still on a steep learning curve and guessing when an object in the centre of view does not seem the right way to get good alignment either when using Alignmaster for Polar adjustment or Cartes du Ciel. I would therefore like to get an eyepiece with a cross-hair reticule for alignment purposes. I assumed the illuminated sort would be what I want but have seen some people say that non-illuminated is the way to go. Is that just because they are cheaper or can they actually have advantages?

Opinions please.

Also, what is the best sort of magnification to use when aigning with one of these? 12.5 mm seems to be a common eyepiece which would give me x120. About right?

Thanks for any advice you can give.

David

[Hugechris]

For aligning my scope I opted for a non-illuminated EP as it was cheaper (but it has the option of an illumination add-on), its perfect for this role. As I live in london there is usually enough sky glow (!) to make out the cross hairs, however for really dark skies its not so easy so will tend to align during twilight. Its a 12.5mm EP and has its uses for observing and for collimating, the lack of illumination has its benefits here.

The illuminated EPs are useful for some forms of auto-guiding by a secondary imaging system but not an absolute must.

[E621Keith]

I'd go for the illuminated version. Unilluminated cross hair can be very hard to see when you have darks skies. Since you are only using your eyepiece for centring, the standard 12.5mm would do.

[Capricorn]

I would opt for the illuminated if the additional cost isn't a problem, at least that way you should be able to see the reticule. It will be damn annoying if you have trouble seeing an unilluminated one.

I think that Astro Baby had something about reducing the brightness if it was too bright.

Check her web site.

Focal length is a bit more of a problem, the 12.5m sounds fair but your scope has a long focal length, I would have gone for a bit longer and relied on the reticule giving the central accuracy while having a wider view. My instinct saying 15mm or more likely 18mm, but that is my preference.

[JohnC]

I would also go for illuminated.

Not 100% necessary but a definite advantage.

[Steve Ward]

The one I just got for drift aligning is illuminated , but it's variable brightnesswise and obviously you can turn the light off all together , great bit of kit and reduced here now........

http://www.scopesnskies.com/prod/scopeteknix/eyepiece/reticule122.html

Covers all needs .

[msh1]

i use this one http://www.skysthelimit.org.uk/illuminated%20reticle%20eyepieces.html works really well and cheap

[JamesF]

Chalk up another vote for illuminated from me.

I could use a non-illuminated one for some of the planets because they'll show up the reticle anyhow. Otherwise without the illumination it would be otherwise unusable. Mine is also a 12.5mm focal length which I've found to be good enough for my purposes.

James

[faulksy]

i use this one http://www.skystheli... eyepieces.html works really well and cheap

thats a good price and from someone with a good rep, thanks for that

[JamesF]

That's the one I have. The only think I don't really like about it is that the top ring of the ep has to be unscrewed to bring the reticle into focus and it feels a bit loose when you get it far enough out. I've never actually had a problem with it, but it's not totally confidence-inspiring either. I'm sure a little PTFE tape around the threads would sort it, but I've not tried yet.

James

[allen g]

If you are getting it for initial alignment try this procedure before you spend your money. when you go to the star you need to align, defocus it so that it looks like a donut, it will then be so much easier to center. I have been doing this and it works perfectly. I have also found that a wide eyepiece (I use a 31 nagler) makes the task easy to spot the star to be aligned. I bought the illuminated type at first and now only use it to train my motors. give it a try.

[BargeGazer]

Thanks for all the feedback. I will try the defocussed doughnut trick first.

I guess re the light or not - you can always turn off the light on an illuminated one but not the other way round!

David

[Merlin66]

The "original" design of most of the illuminated cross-wire reticule eyepieces goes back to Mark I eyeball guiding ( long before PHD and guide cameras...)

We used them with up to a x3 barlow to be able to visually guide long exposures....

The 12.5mm seemed to be "the standard" and hasn't changed over the years.

Antares on their illuminated finders use a 28mm Kellner cross-wire eyepiece, some versions being illuminated - ideal for drift alignment.

You also find various graticule eyepieces in the 12mm range - used for measuring planets, variable stars etc - handy to have.....