Thursday, June 27, 2019

This is the reposting of  messages from ''60mmtelescopeclub'' Yahoo group regarding  a 60x500mm refractor built around a Swift 818 lens :

June 1 , 2019 

A while back Carol was so kind and donated to me a Swift 818 objective with an aperture of 60mm and 500mm focal length.

First I got a Celestron focuser for it ,it is plastic but don't wobble much.
The weak part is not the rack and pinion but the bushing where one insert the eyepiece.
I will change that one with a metal bushing because it could be unscrewed.

Next I got from a friend a very fine aluminium tube which was part of an English  spotting scope.
A  machinist made two adapters ,one for the threaded cell and the other for the focuser.
The outside diameter of the tube is 67mm.
Using two ''C'' shims or segments cut from plastic 3''  drain pipes is allowing to use my home-made clamshell for refractors with  3'' tubes.
I arrived to this stage last year but while checking on the sky I found myself with an issue.
The ergonomy of the telescope was not good because a finder was missing.
Balancing reasons are requesting the tube to be pushed upside so the focuser is next to clamshell ,no place for a finder.
One solution could be to put a finder close to the objective.
A simulation showed this well not work well.
I bought a bracket for an RDF but this cannot be monunted on a tube of such small diameter.
I found myself stuck.
One morning ,this week ,I waked up with a solution in my mind.

All I had to do was a wooden adapter between the tube and the bracket of the RDF.
Thursday I made the bracket.
I'm not very happy with it ,it is a bit slant but it allow the RDF to be colimated paralel with the telescope using the image of a distant chimney.
Today,with help from my Guardian Angel , I was allowed to see Arcturus through the clouds.
I pointed the telescope using the RDF and Arcturus was shining at 20x ,a bright,gold pin point amidst thick clouds.
Even more , looking around the sky, I noticed two stars somewhere close to Zenith.
In a hurry ,I pointed the telescope to one of those stars , of course using again the RDF.
Plain luck : there it was Alcor and Mizar , split in a brighter and a smaller companion.

Finally the telescope is working,as soon as weather will allow I will paint the new telescope.
I uploaded two pics of the Swift 818 Frankenscope.
However ,it is clear for me , I cannot  come close to the beautiful telescopes made by Carol.
But it will see a lot of starlight.
Thank you Carol !
June 3,2019 
Last night,Sunday June 2'nd ,I had the real first light with the Swift 818 lens.
This is the list of objects :
Algieba/Gamma Leonis -resolved 
54 Leo -resolved 
Regulus (distant but dim companion next to a very bright primary ) -resolved
Izar -resolved 
Rho Her -resolved 
Nu Dra -resolved 
Mu Dra -resolved 
16-17 Dra -resolved as a triple star
Epsilon Lyrae- wider pair fully resolved ,tight pair with touching Airy discs
Struve 2470-Struve 2474 : ''the other double-double star in Lyra '' resolved at 20x
Albireo -beautiful color contrast
All stars above were resolved with beautiful ,round Airy discs and thin ,bright diffraction rings.
The powers used were 20x/Plossl 25mm , 56x/Plossl Revelation 9mm and 100x /CircleV 5mm Ortho.

Two failures :Alkalurops/Mu Boo and OSigma 525 resolved only as double stars not triple stars.

DSO objects :

Mel 111-open cluster, did not fit completely in the 2.6 degrees at 20x ,but most of it + double star 17 Com
Steph -1 -open cluster , I counted 12 or 13 stars
M13 - globular cluster,bright , at 125x /Kasai 4mm ortho,I noticed a couple of stars resolved across the cluster but only with averted vision
M92 - globular cluster , small but well visible
M57 - planetary , already visble at 20x, at 100x seen as an oval fuzzy objects,central adrkening not noticed
M29 - open cluster , at 20x it have definitely a hazy aspect ,carefull inspection show some dim stars
M4 - globular cluster ,it was a round hazy patch ,feeble central condensation,visible at 20x but difficult ,no additional details at 100x
M5 - globular cluster ,well visible as a round bright object
M3 - as above , this two objects look very similar in this instrument
M51 - galaxy ,very faint but extended object ,not accepted higher power than 56x
M94 -galaxy , small,oval dim and hazy,slight central condensation
M60 -galaxy ,it was small and very faint

Other objects :

La Superba /YCVn -carbon star ,color index 3 , beautiful
Antares - I watched for a while the scintillation.I learned from ''Astronomie Populaire'' of Flammarion not all stars twinkle the same ,it depend on the spectral types.Something worth closer study.
ISS - at 20x I saw an oblong central body with two wings or extensions on the sides oposite to the direction of movement.

On Jupiter I saw only two belts ,all Galilean satellites were to the West , three forming a pretty triangle asterism very  close to the planet.

No other conclusion than I can't wait for another night with clear sky.
I spent about four hours under the stars of which three hours I was observing through the Swift 818 Frankenscope.
I can tell you ,this is a dangerous instrument because the user tend to develop a sort of addiction.
In the last hour I made observations with the 200mm F/6.16 Dobsonian.
I enjoyed a beautiful view of M13 resolved in many,many stars and I saw galaxy NGC 6207 located very close to the globular cluster.