Home made small rich field telescope

[Guest peepshow]

Some of the best WOW views are by using Rich field telescopes.

Way back in Vol 2 of "Amateur Telescope Maker," there was a chapter on these and for the money and ease of use a 4 inch Newtonion at f4 gave the best for the smaller sizes. 

 

Only about 500mm long it could be easily cradled in ones arms whilst sitting down.  No back bending, squinting or ladders required.    

 

Recently a 4 1/2 inch  f4.5 mirror came up for sale on ebay and with a very kind offer from Petesull for a suitable eyepiece I have started construction. 

 

The tube is a length of vent pipe.  The mirror housing is a round piece of thick plastic with sets of adjusting screws.  Sec mirror spider now being made from plastic etc.

  I might put a ring of resistors around the tube near the mirror if dew is a problem. ( Many R's in parallel fed from, say, 12v should do the trick.) 

But my body heat should keep the mirror end warm

 

A mono pod standing on the ground could be added for extra stability but as the magnification is low cradling it in ones arms should be OK.....don't tell the girl friend you are cradling in your arms

a WOWer

 

So I hope to be  sitting  down in an armchair in the garden soon  and getting the WOW.

RFT by predoodlebug, on Flickr

Edited August 31, 2013 by peepshow

[Brantuk]

Nice one Richard - very ambitious - be interesting to look through those when they're completed.

[+RonC]

Sounds good, keep up the photo's !!

[BAZ]

A great bit of work, I would like to know how many wow's per hour it's capable of when you have it finished! 

[philjay]

Excellent, I used to have a 6" f4 many years ago. Sweeping the milky way is a treat in these scopes

[Tweedledee]

Nice project Richard.

Looking forward to hearing about the views through it.

[Guest peepshow]

MY RFT now finished but not yet properly collimated.

 

Here's the spider made from  6BA studding to support the sec mirror.

 

It is very comfortable sitting and cradling the stars in one's arms.

Here's my Astronomer Royal in another pose.    Just sit in comfort and gaze.

4 1/2" dia. mirror.  1 inch eyepiece.  20 Inch focal length.

 

[dawson]

Wonderful.

 

James

[Guest peepshow]

Last night after the rain washed the skies clean  I had the best session with my little RFT.  Results as one would expect with a x20 4 1/2 inch, Androm neb was there in her oval  fuzziness.     Kemble's casacade too etc.

Because it is hand held, sitting down, it's difficult to find things, especially as I am not familiar with what is up there.

 

So I have made a low power viewer (using old lenses I have). this will be mounted alongside the RFT's 25mm eyepiece.  A small dentist's mirror positioned right next to the eyepiece as mock up photo shows.

 

In this way I can easily home onto objects through the low power, wider mirror view, then quickly transfer my eye to the eyepiece along side it which will be level with the mirror.   That's the theory anyway.

 

A kinda, "Open wider sir" as  my dentist would say.

 

 

Dentist mirror

Edited September 9, 2013 by peepshow

[Guest peepshow]

Using some pipe clips and a length of brass I have now this assembly.

 

The view via the dentist mirror is not as wide as if one's eye was right on the eyepiece

and the view is rotated but it does help to align the main mirror on objects.

The flimsy pipe clips are a bit bouncy so will need replacing with a sturdier construction.

 

(The angled dentist mirror is just above the eyepiece in the photo and is also held on with two more pipe clips)