Taking The Plunge - RDF

[Guest]

I've taken the plunge and ordered a red dot finder from eBay, as I'm fed up with the terrible OEM finder scope.  I take it that it should be easy to set up?

[Floater]

A walk in the park ... 🤞

[Louis D]

If it's one of the ones that originated for rifles and pistols, they're really simple.  Once locked into the finder shoe, just center a star in the main scope, turn on the RDF to its lowest brightness, and then adjust the windage and elevation knobs like azimuth and altitude adjustments to place the red dot in the viewing window on the star.  They're actually simpler than the Telrad and QuikFinder adjustments that have three knobs and require a bit fiddling to fine tune.

[John]

2 hours ago, merlin100 said:

I've taken the plunge and ordered a red dot finder from eBay, as I'm fed up with the terrible OEM finder scope.  I take it that it should be easy to set up?

What scope is it for ?

 

[Alan White]

RDF or Telrad or Rigel, all a great step in quick finding in my book.
That said you can still get hopelessly lost though, I often do, but that's down to numpty, not the kit!

What have you bought?

Edited February 4, 2020 by Alan White

[Frank the Troll]

Easy peasy to set up and use, will take you longer to unwrap it

[Louis D]

I would get one of these and mount both the RDF and a (better quality, RACI?) finder scope at the same time.

I got one for my refractors to mount a finder scope, a laser sight, and a QuikFinder/RDF simultaneously.  It also helps get them farther away from the eyepiece so I tend to bump them less often.

[Guest]

1 hour ago, Alan White said:

RDF or Telrad or Rigel, all a great step in quick finding in my book.
That said you can still get hopelessly lost though, I often do, but that's down to numpty, not the kit!

What have you bought?

It's this one...

https://www.ebay.co.uk/itm/Red-Dot-Finder-Scope-for-telescope-two-hole-fixing/381663633332

[Guest]

2 hours ago, John said:

What scope is it for ?

 

The old Meade 114-900 EQ-1B.

[Guest]

1 hour ago, Louis D said:

I would get one of these and mount both the RDF and a (better quality, RACI?) finder scope at the same time.

I got one for my refractors to mount a finder scope, a laser sight, and a QuikFinder/RDF simultaneously.  It also helps get them farther away from the eyepiece so I tend to bump them less often.

A bit out of my league, at the moment!

[Alan White]

2 minutes ago, merlin100 said:

It's this one...

https://www.ebay.co.uk/itm/Red-Dot-Finder-Scope-for-telescope-two-hole-fixing/381663633332

Has that got the correct foot for you telescope?

Edited February 4, 2020 by Alan White

[Guest]

2 hours ago, Louis D said:

If it's one of the ones that originated for rifles and pistols, they're really simple.  Once locked into the finder shoe, just center a star in the main scope, turn on the RDF to its lowest brightness, and then adjust the windage and elevation knobs like azimuth and altitude adjustments to place the red dot in the viewing window on the star.  They're actually simpler than the Telrad and QuikFinder adjustments that have three knobs and require a bit fiddling to fine tune.

It's a two hole job, so no hotshoe/finder shoe type fitting.

[Guest]

Just now, Alan White said:

Has that got 5he correct foot for you telescope?

Should be, as I've measured several times and ordered once. 😉

[Louis D]

47 minutes ago, merlin100 said:

A bit out of my league, at the moment!

My bad.  I didn't realize it didn't have a vixen style finder shoe.  You can always add one quite easily:

I just swapped in this one for the single screw one that came with my Orion 127 Mak.  It holds dovetails much more securely with its two screws.  Of course, you'd have to either add a dovetail foot to your RDF or order one with the dovetail foot.

[JOC]

Ditto dual finders mounts being the best of both worlds - this is my setup: 

 

With it I can find anything I can see with the naked eye in the centre of the telescope in about 30 seconds flat.  In fact I find that the RDF doesn't even need to be spot on with the optical finder, esp. if I have a mental note of what the difference is.  If it's in the RDF it's usually in the optical path of the RACI and if the RACI is spot on with the telescope I just roughly use the RDF to find things then centre it into the RACI and then I'm in business.  I find there isn't quite sufficient adjustment in the RDF on that mount to get it spot on, so I live with it, but it isn't an issue as I can get the RACI spot on.  NB.  In the UK laser finders are somewhat frowned upon for good reason.

[Guest]

I'd never use a laser pointer, as a friend who used to live in a high rise kept getting a green laser shone at his 12th floor living room window. The police dealt with it and the said laser was confiscated from the youth! 

[Louis D]

6 hours ago, JOC said:

In the UK laser finders are somewhat frowned upon for good reason.

 

3 hours ago, merlin100 said:

I'd never use a laser pointer, as a friend who used to live in a high rise kept getting a green laser shone at his 12th floor living room window. The police dealt with it and the said laser was confiscated from the youth! 

They've become quite popular with American astronomers, especially those who can't crank their head around any more to use an RDF.  I have yet to hear or read of a single astronomer being approached, let alone arrested, by a police officer for using one.

[Alan White]

Louis, the UK being tiny compared to the US is overflown in most areas and laser pointers are a definite no no where planes fly, the CAA take a very dim view on skyward pointing lasers.

[Stu]

38 minutes ago, Alan White said:

Louis, the UK being tiny compared to the US is overflown in most areas and laser pointers are a definite no no where planes fly, the CAA take a very dim view on skyward pointing lasers.

Yep, I'm reasonably near Heathrow and it is not uncommon to count 15 planes in the sky at once!

[Guest]

I live in the flightpath of a local airport and we get international flights heading out over the Atlantic overhead. Unfortunately, there are a minority of idiots who use these devices for the wrong reasons. High powered versions can easily be bought from China over the Internet. I believe they are illegal due to the power levels. It's not something I have much knowledge about. 

[Louis D]

5 hours ago, merlin100 said:

I live in the flightpath of a local airport and we get international flights heading out over the Atlantic overhead. Unfortunately, there are a minority of idiots who use these devices for the wrong reasons. High powered versions can easily be bought from China over the Internet. I believe they are illegal due to the power levels. It's not something I have much knowledge about. 

The cheap green ones can pump out well over 5mW in the infrared due to a lack of IR filtering.  That, and many put out well over 5mW despite saying otherwise.  I'm of the opinion laser pointers shouldn't be used for outreach because little kids are always trying to relieve presenters of them to play with as light sabers.  It gets annoying having to keep reminding them to pay attention to what is being pointed out in the sky rather than the pointer itself.  I blame failed parenting and kids' generally short attention spans.  Laser pointers are fine when there are no kids around, but that's a rarity at outreach events.  I never mount the laser sight at outreach events, either, because kids have a tendency to look down the front of everything on the field, including laser sights.  So, that leaves using them alone in my backyard.

I'm 35 miles north of the nearest airport, and the planes are landing every 10 or 15 minutes and approaching miles east of my narrow viewing window to the south.  Since they're heading south, at worst, I'd hit their backsides if I somehow shot a beam through my trees at them.  They don't seem to take off to the north, possibly because that's where all the landings are coming from, so hitting the cockpit would be next to impossible.  We don't have much in the way of police, sheriff, or ambulance helicopters out my way either.  However, they're super easy to hear coming compared to a high flying airliner.

[Guest]

I fitted the RDF yesterday and aligned it today, when I had more time.  It's not perfect, but close enough for Government work!