Background Information
Since I found that my Celestron Star Pointer (see another article) is inadequate for my C8, I proceed to search for better alternatives. The Telrad and the Rigel Quick Finder are the natural choices, I bought both of them since the shipping cost is too high if I order only one item.
I have a 6x30 finder which comes with the C8 OTA, but since the bracket cannot be removed from the OTA easily, I found it not so portable. At the same time, I'm used to use a unit finder, and that's why I go for these two infamous unit finders.
P.S: I sold my 6x30 Celestron LER finder soon after I got my Rigel Quick Finder.
The Package and the Options
The Telrad comes with a single base, variable brightness control, no battery, and 3 concentric circles of 0.5 degree, 2 degree and 4 degree. It is longer and heavier than the Rigel Quick Finder.
The Rigel Quick Finder comes with two bases, variable brightness control, Lithium battery included, and 2 concentric circles of 0.5 degree and 2 degree. The blinking reticle is a standard feature in the Rigel Quick Finder. It is shorter and lighter than the Telrad, but since it stands on its base, it is actually taller when in operation.
The switches on the Telrad is larger and better placed, so it's easier to use and more accessible. The switches on the Rigel Quick Finder are located on the opposite side when it is in operation, however, I have to say, both are very easy to use.
The Telrad uses standard AA battery and the Rigel Quick Finder uses CR2320 Lithium battery. With the Telrad, you have to provide your own battery and with the Rigel Quick Finder, you have them included in the package.
There are three alignment switches for both of them for alignment.
The Rigel Quick Finder and the Telrad at work
Both works similarly, very easy to view through, with an infinite "eye-relief". Parallax are not a problem in both of them for any person, much better than a red dot finder.
Alignment to the main optics is easy for both units, with the Telrad even easier. It is easier than the Celestron Star Pointer and also a conventional finder in a 3/6 points adjustment bracket. The switches of the Rigel Quick Finder are a bit small, especially the one which control blinking of the reticle, the rest are okay. It's alright for the weather here in Hong Kong weather since it won't be too cold, but if you've to manipulate those switches with heavy gloves on, it would be difficult, if not impossible especially for the blinking switch, but all other switches are large enough, just not as comfortable with the Telrad. Alignment of both units is easier than an conventional optical finder.
The Telrad, having one more larger (4 degree) circle, which is nice for star hopping and it is missing on the Rigel Quick Finder. In a light polluted sky, landmark stars are not always available and so the extra 4 degree of the Telrad is nice, but under better sky, the 2 circles of the Rigel suffice.
The Telrad is larger and it would be awkward to use it on a smaller scope. The Telrad is also much heavier to a degree that the balance of the OTA might be upset. The footprint it casts on the OTA is long as well. Be careful that someone might find their tube rings are hindering the installation of the Telrad due to its long foot print.
To use an unit finder, as usual, you view through the reticle using one eye and see the sky with the other eye. It seems strange and difficult, but it is easy once you try to do so! The sky look exactly like in the star chart, you have more stars or better say, more context, to look for your target. At a light polluted sky, however, an optical finder would be nicer for it provides more light gathering than naked eyes, the magnification it gives also increase the constrast of the targets by darkening the sky background. Better yet, you can augment your Telrad or Rigel Quick Finder with a conventional optical finder. Objects invisible for the naked eyes will be invisible with the unit finders, but there's a chance to glimpse it with a conventional optical finder.
Both are fun and easy to use. I found blinking reticle is not that much useful since you can dim the reticle and it serves the same purpose rather well, in my opinion. However, I guess it will be useful in those truely dark sky which is absent here in Hong Kong, ANYWHERE. Each of them have their own pros and cons, so maybe it's fine to get both of them!
Both finder has adjustable brightness control and the range is wide enough that you can use it without affecting your night vision (not tested in truely dark sky) and you can use it to locate the moon.
Last but not least, you don't have to use optical finder and these nice unit finders exclusively, you can always use both of them. But in my opinion, if you are comparing any optical finder with less than or 30mm aperture, I believe it's better to go for a Telrad or Rigel.
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