SM60 and PST

Back on the 6th October I finally got some time to look at the problems with the EC90. Found that the objective was still mis-aligned and causing focus problems! I can't do much with it unless I remove the SS objective and make up a new front end which will allow better control of the centering/ collimation.I've set up the old Vixen A80Mf to accept the front end adaptor plate and the SM60/BF15. Only had a few minutes before going away to check it out but it looked REALLY good.So why not try to fit the PST etalon as well??The first trial were with the Vixen stopped down to 60mm ( no ERF)Couldn't focus the PST "black body", although the etalon was well inside focus ( the new TS Crayford helped!) I thought I was 10-15mm too far out. Time to cut the tube?????What about re-configuring the adaptors and see what happens?Well, well, well at a back distance of 175mm (from the back face of the PST etalon body) everything came into focus.The set-up was: the German PST etalon front adaptor, PST etalon, 50mm to SCT thread adaptor, SCT to 2" adaptor, 2" to 1 1/4" reducer and then the BF15.The views very absolutely fantastic, The surface granulation and "hot spots" just jumped out. The best images I've ever viewed with the PST etalon. Wow!!!!!!!!!!!!!Unfortunately it clouded over before I could add the SM60 to the front end, but weather permitting tomorrow's the day.I feel that things are finally coming together!! Until I can find the time ( and now the inclination!) to re-work the EC90, I think the Vixen 80/ERF/PST/BF15 will be great fun; and when you add the SM60, double stack, I'm sure magic will happen!!

Trials with SM60/PST mod and Lumicon filter

Finally got enough prolonged sunshine to set up the 80mm Vixen and try some filters/ combinations on the Sun. Seeing wasn't the best but still.SM60/BF15 - as expected; good clear views, plenty of "hot spots", granulation, spiculae all around the edge and two sets of proms. Just does the job as advertised!!SM60/PST double stacked/ BF15 - disappointing! No more detail ( although the image is much darker) than with the SM60 alone; infact seemed a bit worse! ( See below)SM60/ Lumicon Prom Filter ( The Lumicon I gather (??) is supposed to be used with an ERF to show at about 1A, the proms - It states on the body " don't use with apertures above 4" " It's only a very narrow band 1 1/4" filter in a tilting housing)Surprising! Didn't do ANYTHING for the surface detail, but it certainly acted as a very efficient BF for the proms. Just took half a turn of the small adjusting screw to dramatically improve the visibility of the proms. They actually looked better than through the BF15! ( Must try the original IOM BF10 which is also adjustable). Hmmmmm.Pulled off the SM60 and fitted a C-ERF; tried the Lumicon filter.. wooow the image is FAR TOO BRIGHT!!!! grabbed an ND3 filter and put that in front of the Lumicon. Toned it down so at least the view was "pleasant". Nothing easily (is there anything?) visible on the surface, and in spite of many adjustments/ re-focuss etc etc I couldn't pick up the proms I'd seen earlier!!!!Ok, move on; in goes the PST etalon (with a back focus of about 180mm); Geez it's BRIGHT, out comes the ND3 again....Well I tried, I honestly tried, but what ever I did, never gave clear view of the granulation and I couldn't see any of the faint promsThe image was definately in focus????!!!! What's going on here???Pulled the etalon off the rear adaptors and re-fitted it to the PST Black Body, back in the Vixen.........Mmmmmmm No focus; it needs to go in further......So far SM60/BF15 10/10, SM60/ Lumicon 7/10 ( for great proms!), C-ERF Lumicon 0/10, PST mod 0/10At they say in the UK; time for a cuppa!!!Obviously the PST etalon wasn't getting to that design position of 200mm in-side focus with the Vixen....HmmmmTime to bite the bullet; off to the shed, out with the hacksaw and drill and 20 minutes later the Vixen tube is 40mm shorter (with a high squeaky voice!!)The clouds are beginning to roll in ( It is the UK, you know!).... quickly set up the PST black body without even the C-ERF ( the sun's getting low... yes I KNOW the safety assessment says.....) WELL, WELL, WELL before I even tune the etalon; the sun pops into focus and the surface granulations are easily visible, a quick turn of the tuning ring and out pop the proms... YES...YES...Clouded out before I could re-fit the SM60 to try the double pass.Executive summary:If you have the money left in your pension plan ; go for the SM60/ BF15 - fantastic!!Don't buy the Lumicon unless you already have a SM40/SM60 (or a modded PST!) and need an equivalent BF15 ( unfortunately for proms only)If modding a PST, the DISTANCE INSIDE FOCUS MUST BE CLOSE TO THE DESIGN 200mm, or you will be embarrassed and very disappointed.Who says the solar minimum is boring.

Solar telescopes- Part1

Over the last few months I've been lucky enough to collect together some interesting solar observing equipment. There's always been some passing interest in the Sun, probably due to the spectroscopic obsevations.
Oldfield ( Hong Kong), http://osastrolog.blogspot.com/2008_06_01_archive.html
impressed me with his steadfast observations under extreme hardship using PST and later a Solarmax SM40 set-up.
After much trial and tribulation with "rusty" objectives, I managed to aquire an Ha PST. The initial views were good and I saw Prominences for the first time. The surface detail was difficult and it took a bit of practise to see the granulations.
Trying to take photographs with the PST turned out easier than I thought, once a Barlow had been added! I quickly found the x5 Powermate gave "Newton Rings" - interference bands across the image, whereas the Klee x2.8 seemed to work very well. The Meade LPI and std webcam worked well.
Looking for more contrast and resolution I chased up and found a SM40/ T-max/BF5 filter combination which could be double stacked on the PST. This dramatically improved the detail and resolution. Faculae, granulation and Proms were very much easier to see although the image, with the reduced bandwidth ( around 0.5A) was much fainter.
Mounting the SM40/BF5 combo on the ED80 gave very good, clean and crisp views, generally ended up with the TV10.5Plossl. I've got to say, more impressive than the PST.
The field was limited by the BF5 filter aperture ( designed for a focal length less than 500mm, the ED80 being 750mm) and I managed to find a second hand original BF10 diagonal/ blocking filter.
When it arrived I was surprised to find it looked nothing like the Gold Coronado BF5 I had.
It had a black CNC machined body and also had a tilting screw to provide fine adjustment of the filter position thereby "tuneing" the centre pass position ( when solar flares and/or Proms are moving upwards and outwards from the Sun's surface their speed gives rise to a Doppler shift of the Ha wavelength; the faster they move the more the Ha is shifted towards the blue end of the spectrum). The combo of the SM40 and BF10 proved ideal. Good full disk views, easier full frame images and a clean bright image.

Projects in Progress

Here we are in Feb 2008, and still have some interesting projects on the go. The design of a cheap, effective ERF ( Energy Rejection Filter) to use on the Genesis 4" telescope is #1 at the moment. Based on a UV-IR filter from ROSCO, Sydney, Australia and a #25 Red from Surplus Shed. The etalon filter has been removed from a PST and adaptors made to fit the 2" focusser.