F50 Finder or Telrad

[coliea]

I'd like to get some kinda finder for my Stellarvue 102 but am not sure which way to go. Bearing in mind that I have fairly light polluted skys here in Worcester what would you guys recommend - a non-magnifying Telrad type or Stellarvue's own F50 finder?

I was leaning toward the Telrad, but am beginning to wonder if I can see enough naked eye stars to make star hopping doable. That's what has me considering the F50.

This CN review seems to rate the little Stellarvue and it was S&T's hot product of 07: http://www.cloudynights.com/item.php?item_id=1324 David Elossor's setup about a third of the way down would look very similar to mine if I decided on the F50. Or... should I forget about a finder and go with a wide 2" "finder" eyepiece in the SV102 instead.... although having said that the little F50 has a massive 5.75 deg TFOV with the supplied eyepiece.

Whatcha reckon?

1. Telrad

2. F50 finder

3. Widefield EP

Ta

Col

[philsail1]

Hello "coliea" - and welcome to stargazers lounge (if you are not already a member!).

You have a 102mm Refractor, and light polluted skies.

I would tend to go for a right angled optical finderscope with a decent aperture (to gather the light).

The Stellavue one seems to excellent - a quality "Nano" (as Cloudy night's review says) refractor in it's own right.

In my opinion "right angled (right way up image) optical finders are ideal for use with refractors and Maksutovs, as the scope's eyepiece is at the rear of the scope, so whereever you point the scope the eyepiece (and optical finder) are always on the same optical "train." (whereas in a Newtonion, the eyepiece some swivels to some quite awkward angles, taking the right angled optical scope's eyepiece with it. When you swivel the right angled finderscope to a more comfortable viewing position, it can lose it's alignment with the main scope).

I have used simple "red dot fiddler's" (oops! I mean finders!) but personally found them a bit difficult to pick up all but the brighter stars. Of course, much depends upon the make and quality of a red dot finder - and the users eyesight!

Best wishes for whatever you choose,

Regards,

philsail1

[paulastro]

One consideration may be if you intend looking for planets in the dawn or evening sky. An optical finder will allow you to search for the planet when the sky is quite light and not visible with the naked eye- with a red dot type finder of course you can't. Finding a planet before it is dark can give you some extra precious minutes observing time.

Regarding right angle/straight through finders, I've never been able to get on with the right angle variety, I have always found them very difficult to align with the object you are trying to find. Having said that, I know plenty of observers in both camps - which is presumably why manufacturers supply us with both!

Regards, Paul

[Ford Prefect]

Check this out

http://stargazerslounge.com/index.php/topic,33046.0.html

[coliea]

Thanks guys for the suggestions. That Telrad thread originally got me thinking of one as I like the idea of Telrad star hopping charts being freely available. I was also toying with the idea of mounting it on my UniStar instead of the scope - see this thread: http://tinyurl.com/abqy26

Telescope House has the Telrad currently for £31.80 delivered, so I might give it a go. If it doesn't work out I won't have wasted too much money and can always sell it on.

Col

[philsail1]

Hello again "coliea"

I use a simple Skywatcher 6x30 right angled optical finderscope on my 90mm Maksutov. This finder is rated as pretty poor by any standards, but I find it easy to use in quickly locating the planets, and most bright stars. (It is no good for deep sky obviously - but then again neither would any of the red dot type of finders be).

In use, the right angles finder is easy to use. (after ensuring that you have aligned the finderscope to the centre of the main scope (using a high power eyepiece and aligning scope and finder on a distant point - in the daylight).

All you do is roughly sight along the main scope's barrel until the object you want to look at is in line with the main scope's barrel, then look through the finderscope. The object should be somewhere in the finderscope's wide field of view. Just move the scope until the object is in the centre of the cross on the finderscope, and the object should be spot on in the centre of the field of view in the main scope.

However, a right angled finderscope is not so good when using a Reflector mounted on an Equatorial Mount, as the eyepiece (and finderscope) often assumes some unusual positions when the scope is moved between one Astronomical object and another. I would say a straight through finderscope is much more useful in this case as no matter what angle the main tube assumes on the mount, the finderscope will always be pointing parralel to the tube.

I would go for as large as optical finder as you can afford. The wider and brighter the field of view, the better. Magnification is not so important.

Well, that is only my personal viewpoint of course.

Best wishes for whichever finderscope you eventually choose.

Regards,

philsail1

[johninderby]

I've had a couple of the F-50 finders and can confirm that they are optically superb finders. The supplied eyepiece has such fine crosshairs though that it can be difficult to see them if an illuminator isn't used. However other reticule eyepieces also work so you can get around that problem easily enough. One other problem is that if you use an illuminator on the eyepiece the weight of it can cause the focuser to rotate by itself.

The Orion 9x50 Right Angle finder comes a very close second though (and at about half the price) and I find the thicker crosshairs easier to use although of course you can't use an illuminator. Surprisingly a lot of people seem to think that you can't focus this finder. You focus by turning the lens cell / dewshield at the front, once you have slackened off the locking ring of course.

John