RDF or finder-scope for a skywatcher 150PDS

[MG01]

Happy New Year you wonderful people!

SO...following a fun first light on Boxing Day with my Son's new scope, we're wondering what recommendations people have for replacing the rather wobbly finder-scope that it comes with.

I've a Baader Skysurfer on my imaging rig but don't really want to spend quite so much if possible.  Any other (budget) RDF's or finderscopes that people recommend?

ALSO...if anyone knows the size of the secondary collimation screws that would be great as I'm obviously too tight to pay for bob's knobs. 😆

[jock1958]

I have a Sky Surfer III on my small 60mm refractor and a combination of a Telrad and Skywatcher RACI finder on my 100mm refractor. All those finders are relatively inexpensive, the Telrad is my favourite as it does the job the best IMO, downside it’s a bit bulky and not that pretty! 
Another option is a Rigel Quickfinder, works similar to the Telrad 🤔

Edited January 1, 2023 by jock1958

[Guest]

I swear by a dual mount with a RACI in one position and a green laser pointer in the other.  I have no use for any of the red dot type stuff.  

Edited January 2, 2023 by Mike Q
Photo added

[Franklin]

I might be old fashioned but I much prefer an optical finder than an RDF, for visual anyway. RDF's are great for pointing at the big bright stuff but your lads 150 can go deeper and a 9x50 optical finder can really help in finding those objects that are just not quite visible to the naked eye.

[Carbon Brush]

What is 'sons new scope'? That (in my view) influences finder choice.

[jock1958]

2 minutes ago, Carbon Brush said:

What is 'sons new scope'? That (in my view) influences finder choice.

Skywatcher 150PDS I believe in the title 🤔

[Ricochet]

What eyepiece will he be using as a finder? If he's only using 1.25" eyepieces he will be limited to ~2.2° so the question is whether he thinks that is wide enough to find things with. If it isn't, which would be my initial assumption, he will want a RACI finder in conjunction with an RDF. If he can get a satisfactorily wide view through the eyepiece then the optical finder can be omitted and the RDF will suffice. 

For comparison with my dob my widest field is 1.8° and I use a 9x50 RACI and Telrad. At the other end of the scale with my 72ED I can get 3.9° (1.25") and so only need an RDF. 

[oldfruit]

Telrad all the way for me. There are a lot of free useful Telrad finder charts on the internet. Also if you are using Stellarium free software, there is the option to use a Telrad reticule.

Works every time for me.

[oldfruit]

Stellarium Astronomy Software

 

[Spile]

The thumb screws on the 200P are M4 25mm available from eBay.

 

[Ratlet]

Telrad or quickfinder.  I use a quickfinder myself.  I've got a 130pds and use a combination of it, a 32mm plossl and skysafari to starhop. Quite easy to find stuff with that.  The 150pds should have come with a 28mm ler eyepiece (great eyepiece btw) which will give about a 2° FOV which should be fine for star hopping and viewing.

Edited January 2, 2023 by Ratlet

[PeterStudz]

14 hours ago, Ricochet said:

What eyepiece will he be using as a finder? If he's only using 1.25" eyepieces he will be limited to ~2.2° so the question is whether he thinks that is wide enough to find things with. If it isn't, which would be my initial assumption, he will want a RACI finder in conjunction with an RDF. If he can get a satisfactorily wide view through the eyepiece then the optical finder can be omitted and the RDF will suffice. 

For comparison with my dob my widest field is 1.8° and I use a 9x50 RACI and Telrad. At the other end of the scale with my 72ED I can get 3.9° (1.25") and so only need an RDF. 

Ask 1001 people about finders and you’ll get 1001 different “must have” solutions 😀. They are very personal and there isn’t a right answer.

However, for me the above suggestion is sound advice. Eg I have a 114mm reflector and a 200mm Dob. My house is in an urban area with much light pollution and this might have an impact on what will work for you. 

On the small 114mm I use a cheap and light RDF plus a low power eyepiece as a finder. I’ll use the RDF in order to get in the right part of the sky. Because of light pollution more often than not that’s just a black part of sky - no stars in the RDF. Then I use a low power eyepiece as a finder in order to star hop. This effectively gives me a stable, comfortable “RACI” with a 114mm aperture. How on earth anyone star hops with a straight through finder I’ll never know!

With the 200p Dob it’s not easy to use an eyepiece in order to get the magnification low enough to use as a finder. For me the solution is to use a cheap RDF plus RACI. If I had a 150PDS I’d probably go down this route but you could try the other option and see if a cheap RDF plus low power eyepiece works for you. 

Edited January 2, 2023 by PeterStudz

[MG01]

Thanks for the feedback.

I guess I'm used to RDFs because for imaging (using a frac) I really just want to align to some bright stars, but even that isn't necessary now I'm getting into platesolving for polar alignment which then gives me good enough pointing and tracking accuracy to be able to locate most things with a slew and a bit of a spiral search if necessary.

The reason I dislike the include finder is that 6x30 has a pretty small eyepiece to try and get behind in a somewhat cramped position when pointing above the horizon.  When using an RDF you can actually be further away from the unit and still accurately position the dot in the sky.

But I do like the suggestions of a RA finder....That will certainly be easier to look through.  I guess I'm still getting used to being at the wrong end of the scope! 😛 

[MG01]

15 hours ago, Ricochet said:

What eyepiece will he be using as a finder? If he's only using 1.25" eyepieces he will be limited to ~2.2° so the question is whether he thinks that is wide enough to find things with. If it isn't, which would be my initial assumption, he will want a RACI finder in conjunction with an RDF. If he can get a satisfactorily wide view through the eyepiece then the optical finder can be omitted and the RDF will suffice. 

For comparison with my dob my widest field is 1.8° and I use a 9x50 RACI and Telrad. At the other end of the scale with my 72ED I can get 3.9° (1.25") and so only need an RDF. 

Primarily using the 2" 28mm that it came with for finding targets, so approx. 2°   I'm not ready to let him loose with our 35mm pan yet!

I'm torn between a rdf so he can quickly align and then use the handset for finding targets vs RACI that will possibly teach him better star hopping....but may frustrate him at first?

I can see merits in both so may come down to try one and see how we/he gets on.

[Franklin]

Right-angled 9x50 just forward of the focuser, if you keep it at the same point you won't breathe on your eyepiece when looking through the finder which can mist it up. Position depends on whether you or your son is left or right eye dominant. Telescope makers seem to put the finder shoe on their scopes in a not very ideal place.

[cajen2]

+1 for a RDF and  a RACI for a Newt. I use the RDF for getting the scope in approximately the right area and the RACI for centralising the target. One thing nobody's mentioned is how easily a slight touch can put finders out of alignment, so it's good having two.

A space-saving mod is to use a twin finder mount. Here's mine:

[MG01]

10 minutes ago, cajen2 said:

+1 for a RDF and  a RACI for a Newt. I use the RDF for getting the scope in approximately the right area and the RACI for centralising the target. One thing nobody's mentioned is how easily a slight touch can put finders out of alignment, so it's good having two.

A space-saving mod is to use a twin finder mount. Here's mine:

Nice setup there...Is that the Skywatcher RACI?  I think I'm going to get one of those...a bit more expensive than I was planning on spending this close to Christmas but  it almost feels like an necessity to get the most out of the scope. (at least I can plead to the budget holder that it's for the kids!!) 😆

[Franklin]

I have a spare, unused one if of interest, I'll PM you.

[cajen2]

55 minutes ago, MG01 said:

Nice setup there...Is that the Skywatcher RACI?  I think I'm going to get one of those...a bit more expensive than I was planning on spending this close to Christmas but  it almost feels like an necessity to get the most out of the scope. (at least I can plead to the budget holder that it's for the kids!!) 😆

It's a StellaLyra one (probably similar). It's slightly cheaper than the SW one. Astro Essentials do one which is cheaper still.

[PeterStudz]

I made a bracket for my RDF out of bits I had down the shed - a metal bracket, some scrap plywood, screws and bolts. It cost virtually nothing, is light and has the RDF and RACI as close together as possible. The RACI that I use is the Astro Essentials - works fine. 

Edited January 2, 2023 by PeterStudz