Merlin66
10-10-2008, 03:27 AM
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-focus 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 proms
The 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 0/10
At 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....Hmmmm
Time 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.
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-focus 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 proms
The 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 0/10
At 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....Hmmmm
Time 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.