Got some sun early this morning. Nothing visible on the surface, AR1005 seems to have faded from view.
Using the ED80 with the JMB solar filter, this gives a clean white image at about x50. There were hints of surface granulation and texture.
Put some coloured filters in the AE filter wheel to see if any of them made any difference to the view ( in terms of contrast or resolution). Couldn't focus with the TV diagonal! ended up going straight through and found I was at the opposite limit of travel! Needed to ease the eyepiece out by 10mm.
Results:
Yellow#15 , Blue#80a, Red#23a , Red#25 made no real difference
Green#56 - this filter seemed to make the surface granulations and texture more obvious. Worth re-trying when there's a bit more activity.
Also tried:
Meade Series 4000, Narrowband LPR - blueish image but no impact on resolution.
and
Baader 7nm Ha - expected improved contrast, but other than dimming the view, not much better detail seen ( if any!)
So the conclusion was, if working in white light maybe a Green filter may make the surface detail easier to see.
Thursday 16 October 2008
Sunday 12 October 2008
Impressive sun spot group - 11th Oct
Just set up to re-test the modded PST and a large sun spot group on the E side jumped out. Even in white light through the 7x50 finder it's easily visible.
11:02am Another even larger spot closer to the centre has just erupted in front of my eye's!!!!!! Very large with a bright eruption patch, changing as we speak.Both easily visible in White light with finder..............................
11:20 Second spot fading to a large distrubanceEven my long suffering wife was suitably impressed!!!Something is definately going on....
11:02am Another even larger spot closer to the centre has just erupted in front of my eye's!!!!!! Very large with a bright eruption patch, changing as we speak.Both easily visible in White light with finder..............................
11:20 Second spot fading to a large distrubanceEven my long suffering wife was suitably impressed!!!Something is definately going on....
Friday 10 October 2008
Modded PST - Success at last
Very windy with high cloud, but I just had to test out the PST black body on the cut-back Vixen 80.Even under these conditions the image came cleanly into focus and the tuning ring brought out the surface granulation and "hot spots" Not much in the way of proms but everything looks 100%.For anyone who still has some doubts about the PST mod; honestly you will not regret making the change; the images are far, far, superior than you get with the 40mm basic system.At a stopped down aperture of 60mm, an 1 1/4" #25 Red + UV-IR filter screwed into the german PST nosepiece works well with no obvious heat build up. A cheap way of starting the mod????Should have believed the calculations we did almost 6 months ago: the optimum position of the PST etalon is very close to the calculated 200mm inside focus. As I've found, other positions will give an image but certainly not as tight and clear as when it's positioned correctly.Using the PST black body is the fastest way of verifying the position. If it focusses, then you're pretty close!!I'll get some confirmation images with the DMK as soon as conditions improve.Also, I found the website for the Lumicon Prom Filter; states that the filter is a narrow band 1.5A, and MUST be used above f20 ( up to f60), with an ERF. I'll put a 45mm aperture mask on the Vixen and re-try.
Thursday 9 October 2008
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.
Monday 6 October 2008
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.
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.
Thursday 2 October 2008
Argos TSO ( Tin Shed Observatory)
During September I built a small observatory based on a 8' x6' tin shed kit from Argos.
The metal frame was very straight forward to erect and I used 50 x50mm framing to support a run-off track, used two sets of three 50mm castors; side seals were 5mm marine ply. Only took a couple of days and the results are great. Certainly NOT over kill ( it has to be a temporary construction as we are renting) but does the job.
Just big enough for the 12" LX200... an 8' x8' would be better!
First light for 200mm Littrow
Finally managed to the the 12" LX200 and the Littrow to actually image a star spectra ( Vega)
A series of 4 sec exposures as the drive was not working well ( see comments about balance below).
Found out quickly, even with the safety bracket in place that the metal dew shield ( 1200gms) at the front doesn't balance 1500gms of spectro hanging at the back!! The Dec bearings are so stiff ( the original nylon ones) it's very difficult to tell when the balance is correct. You only really find out when the Dec drive overloads and doesn't work!!
Must remember to re-set the grating micrometer to the ZERO position before trying to find a star image!! Must have wasted 15min before I realised the problem!
Also found difficulty in getting a focussed star image on the slit. I had the 32mm Pl in the beamsplitter with a diagonal; could n't get my head into position otherwise ( old age!) and found that when eventually I got a reasonably focussed image on the slit the eyepiece showed it well out of focus. Guessing an additional 25mm or so spacer needed between the beamsplitter and the spectro.
Two options:
Use the QHY5 guide camera only for aquisition and drop the diagonal. Need to try it out to see what the FOV is like. I did manage to position the star on the slit just by noting the star position on the finder cross wires, so may be doable.
Second option is to add a spacer in front of the Spectro to accommodate the diagonal distance. This would mean the spectro would sit even higher on the back end ( BTW at the moment it's impossible to use the guide scope; not enough clearance at the back; either remove it and rely on the beamsplitter ( good option!!?) or relocate it further towards the front end....balance issues?) and making up a new safety bracket ( no big deal)
I'll try the QHY5 first... see how we go.
It's also difficult to see where the star is relative to the slit.... need some sort of back lighting (??) to illuminate the slit edges, and then should be able to see where the star image is sitting, maybe a small red LED in the body of the spectro which can be switched on briefly....
Other than that, the Canon 350D seemed to record a spectrum in a 4 sec exposure!!
I got about 10 exposures; now need to figure out how to combine them before applying Vspec for analysis. Didn't have the neon connected for these trials. I'll wait until I get the 3V supply sorted out.
The dew shield and heater kept the front end about 1.5 deg above ambient and the corrector seemed to be clear ( total observing time about 2 hours); the benefits of the Argos TSO ( Tin Shed Observatory) were appreciated!!!!
A series of 4 sec exposures as the drive was not working well ( see comments about balance below).
Found out quickly, even with the safety bracket in place that the metal dew shield ( 1200gms) at the front doesn't balance 1500gms of spectro hanging at the back!! The Dec bearings are so stiff ( the original nylon ones) it's very difficult to tell when the balance is correct. You only really find out when the Dec drive overloads and doesn't work!!
Must remember to re-set the grating micrometer to the ZERO position before trying to find a star image!! Must have wasted 15min before I realised the problem!
Also found difficulty in getting a focussed star image on the slit. I had the 32mm Pl in the beamsplitter with a diagonal; could n't get my head into position otherwise ( old age!) and found that when eventually I got a reasonably focussed image on the slit the eyepiece showed it well out of focus. Guessing an additional 25mm or so spacer needed between the beamsplitter and the spectro.
Two options:
Use the QHY5 guide camera only for aquisition and drop the diagonal. Need to try it out to see what the FOV is like. I did manage to position the star on the slit just by noting the star position on the finder cross wires, so may be doable.
Second option is to add a spacer in front of the Spectro to accommodate the diagonal distance. This would mean the spectro would sit even higher on the back end ( BTW at the moment it's impossible to use the guide scope; not enough clearance at the back; either remove it and rely on the beamsplitter ( good option!!?) or relocate it further towards the front end....balance issues?) and making up a new safety bracket ( no big deal)
I'll try the QHY5 first... see how we go.
It's also difficult to see where the star is relative to the slit.... need some sort of back lighting (??) to illuminate the slit edges, and then should be able to see where the star image is sitting, maybe a small red LED in the body of the spectro which can be switched on briefly....
Other than that, the Canon 350D seemed to record a spectrum in a 4 sec exposure!!
I got about 10 exposures; now need to figure out how to combine them before applying Vspec for analysis. Didn't have the neon connected for these trials. I'll wait until I get the 3V supply sorted out.
The dew shield and heater kept the front end about 1.5 deg above ambient and the corrector seemed to be clear ( total observing time about 2 hours); the benefits of the Argos TSO ( Tin Shed Observatory) were appreciated!!!!
Wednesday 1 October 2008
Near Disaster!!
While fitting the Littrow, with the Cube Beamsplitter to the 12" LX200, the 1 1/4" fittings rotated and dumped the spectroscope onto the floor, via a couple of bounces of the edge of the table!!!
You know that feeling you get when you cut yourself with a sharp knife??? Just like that!!
A lot of bad rattling noises from the spectroscope.....
That was on Friday, the 26th ( double the 13th!!)
Pulled the spectro apart and found the collimating lens had been knocked out of the holder and it had dropped forward onto the grating!! Some slight scratches on the grating, but not too bad.
The slit and prism etc seemed OK.
Took the best part of the day to re-set and re-glue the collimator, a mixture of using the laser beam and Cheshire eyepiece.
Today ( 1st Oct) finally got the chance to check the focus with the Canon 350D body.... looks OK.
So... I've already made up a holding bracket which will positively clamp the body of the spectro to the Meade scope. This MUST be used all the time!!
You know that feeling you get when you cut yourself with a sharp knife??? Just like that!!
A lot of bad rattling noises from the spectroscope.....
That was on Friday, the 26th ( double the 13th!!)
Pulled the spectro apart and found the collimating lens had been knocked out of the holder and it had dropped forward onto the grating!! Some slight scratches on the grating, but not too bad.
The slit and prism etc seemed OK.
Took the best part of the day to re-set and re-glue the collimator, a mixture of using the laser beam and Cheshire eyepiece.
Today ( 1st Oct) finally got the chance to check the focus with the Canon 350D body.... looks OK.
So... I've already made up a holding bracket which will positively clamp the body of the spectro to the Meade scope. This MUST be used all the time!!
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