Finders on Dobson telescopes

[Piero]

I am not a Dobson user (yet! ), but I would be interested in knowing how do people find the straight magnifying finder on classic 1200mm focal length Dobson telescopes (e.g. 6" F8, 8" F6, or 10" F5). 

I assume that apart from children or very short people, most owners of these telescopes observe sitting on a chair. If so, is the straight finder comfortable? How about pointing at the zenith? 

Personally, I like straight finders as they allow me to point at the target area in an obvious matter. However, I have only experienced this with a newton on equatorial mount which raised the eyepiece position (and therefore the finder) at my height when standing up. I think I would struggle if I had to sit on a chair though.

And for those using a Right Angle Finder, do you always use it in combination with a Telrad or spot the target area 'by feel'? On my TV-60 I don't have a straight-finder or red dot or telrad, but I generally point making a broad proportional distance between the target location and the diagonal (e.g. left-diagonal-border : target location ~ right-diagonal-border : target location). Although this is very unprofessional, I can spot (for instance) M13 generally straightaway with eyepieces giving FOVs between 1.5 and 2.7 degrees.  

I would be very interested in reading your opinions. 

Thanks, 

Piero

[swamp thing]

I have a tetrad and RACI finder on my 10" scope. I find a 2" riser on the Tetrad helps to make it more comfortable in use.

[baggywrinkle]

I have a Rigel Quickfinder on mine.

It did come with a 9x50 straight through which I dislike intensely as it is awkward to use. The should use RACI types as trying to peer through a straight through near the zenith is a pain in the neck...pun intended.

The Rigel works well for me as it stands well off the tube and is easy to line up.

[estwing]

Raci and a telrad on mine

[faulksy]

red dot, raci and nexus on mine

red dot to get it near then the raci to fine tune

[Ju Piter]

red dot finder,RACI finder on my little heritage 130p

soon to be moved to my 130pds

[Stu]

I have a TelRad on my 10", and also a home built 80mm RACI if needed. I think the combination of a zero gain 'area' finder with a RACI works very well.

I too, often use your 'unprofessional' method of estimating the position of objects and placing the TelRad circles on it rather than star hopping all the time. I generally find it faster for objects I'm familiar with eg M13, M27, M57 etc

[Piero]

Interesting! It seems that the combination RACI+zero finder is a successful match for many, whereas nobody seems to use a straight finder.. 

I guess many people have an unused straight finder at home then as these are generally sold with telescopes 

[John]

Another one here who uses a Rigel Quikfinder and an 8x50 RACI optical finder with my 12" dob. I have had straight through finders on scopes and I have used them but not for very long before changing them for the RACI variety !

I've tended to sell any spare ones off once I got an RACI replacement although I still have the original straight through 6x30mm Vixen finder that came with my Vixen ED102SS refractor because it's the original Japanese made item.

[ronin]

Know one person that uses the straight through finder. Just puts his head on the tube, looks through finder and that's it.

People likely have 2 as it covers more options, just more items to keep aligned.

[astronymonkey]

I also use a red dot and a raci, I dont know why they supply straight through finders with dobs as they are a bit of pain.

Cheers

[Tinker1947]

My Finder that came with the Dob hasn't been out of its box, i use a Telrad on a 4" stand-off base....nothing else required....

[JeremyS]

I use a straight through finder on all my scopes, including Dob. Never had a problem. I sight along the finder to get the scope pointing roughly in the right direction, then move my head to position my eye behind the finder to align the finder cross hairs with the target. Not so easy to do with a right angle finder.

[John]

I find having the 50mm optical finder really useful for tracking down small and faint objects. Even though I can't actually see the object in the finder it shows stars down to around the faintest shown on the Uranometria star atlas and because it's an RACI finder I can match the star patterns in the FoV with those on the chart and, hopefully, pinpoint my target object when I look through the eyepiece. It worked, for example, when I was looking for the quasar 3C 273 which is magnitude 12.9. It's a point source which is below the threshold of my optical finder of course but I used the finder to get the scope on the correct grouping of 8th and 9th mag stars (as shown on the charts) and then was able to use the main scope to see the faint target object.

[FenlandPaul]

+1 for Jeremy's method with a straight-through Finder. I get pointing in roughly the right direction with both eyes open, but right eye lined up with the finder and my eyes about 6 inches back from the finder. This helps me to see both the wider area of sky and the finder view at the same time. Once I'm in the right ball park I press in to the finder to tweak position.

But that's on a 12" f/5 so not quite so back-breaking. It's the method I've always used and for reflectors it works for me.

However having recently acquired a couple of fracs I need to think about a RACI as it can get very uncomfortable trying my dob method.

For some reason I've never got on with zero magnification finders like red dots.

[laudropb]

Just could not get on with my straight through finder. Just not much good at limbo dancing. Got a RACI but struggled a bit to locate things with this. Like most of the others I solved this by adding a Rigel. Preferred this to the telrad because it was smaller.

[niallk]

Straight through stock finder on my 10", partnered with a Telrad. Keeps me flexible!

Argo Navis DSCs plus another Telrad only on my 15".

[kev100]

I use the straight through finder on my 10in. Don't normally have any problems with it except on the odd occasion when scanning at zenith when it can get a bit uncomfortable if finding the object takes more than a few minutes. If I start getting a bit stiff necked I move on to something else.

[Piero]

I use the straight through finder on my 10in. Don't normally have any problems with it except on the odd occasion when scanning at zenith when it can get a bit uncomfortable if finding the object takes more than a few minutes. If I start getting a bit stiff necked I move on to something else.

That was my thought about the difficulty at pointing at the zenith. 

As a curiosity, assuming you observe sitting on a chair, can you use the finder without the need of adjusting your sitting position? 

Thanks!

[Moonshane]

another vote for Telrad plus RACI.

the only scope I don't have both on is my 80mm f6 (just a red dot on that) as it's such a short scope/wide field that the object is usually in the field at low power with just the rdf.

[kev100]

Hi Piero,

I do take a garden chair with me' but it's not adjustable, so I only use it when I'm observing lower objects, and only once I've found the object, not when I'm using the finder.

I tend to avoid zenith generally, unless the object I'm after is easy to find. If there's something I want to see there, I'll just wait a month or two till its lower and easier to observe.

Kev

Sent from my iPad using Tapatalk

[Charic]

I prefer my straight through 9x50 finder with reticule,  when observing, seated from my garden observatory,  keeping  both eyes open when viewing. I  use the Telrad at a much darker sites.

If you fit a wide field eyepiece to the scope, you can negate the finders when the scope is pointed at Zenith, which alleviates  any neck twisting beneath the finders?

I have never used a RACI yet to correct the finder image. The telescopes  image  is still  inverted?   Practice  makes perfect,  I just find it natural to locate with the 9x50 then view  through the EP in use.

[John]

.....I have never used a RACI yet to correct the finder image. The telescopes  image  is still  inverted?   Practice  makes perfect,  I just find it natural to locate with the 9x50 then view  through the EP in use.

RACI = Right Angle Correct Image. It's the same as we see with our eyes.

I think whats more important though is to find something that works for you

I use a wide angle eyepiece as a finder sometimes as well. The more options the better when finding these pesky dim and distant objects that we astronomers insist are interesting

[faulksy]

I use a straight through finder on all my scopes, including Dob. Never had a problem. I sight along the finder to get the scope pointing roughly in the right direction, then move my head to position my eye behind the finder to align the finder cross hairs with the target. Not so easy to do with a right angle finder.

your right and best way but twisting my head at the zenith like a owl hurts after a while

[Piero]

It's interesting to read about different experiences with finders. 

Thankfully there are a few choices to match all users' tastes! 

As Kev100, I don't often observe targets at the zenith. No a real problem to find them, but rather to track them with an alt-azimuth mount. 

Thanks everyone for your answers.