November-December 2006 and up to May 2016
and recent developments
I have revived the rusted BF10 blocking filter with a KG3 filter from ebay as suggested by Mark Townley and it works quite well but with slightly reduced resolution, probably the optical quality of the filter is affecting the image.
After getting a B600 Lunt CaK module a while ago (2008) I have had some good results with that on the ED80 and ED100, close ups and full discs.Now trying double stacking Ha with the parts I have, to get better contrast with proms and surface in the same exposure. I would like to pursue this but my 75mm etalon doesn't have the best flat field. The LS75 turns out to be too far offband to work for full discs. It needs so much tilt that the sweet spot area is a narrow strip that does not cover the whole disc area. A better result was obtained by the SM40 which has a more even filter effect. It is also usable with the outer cover and ERF removed which gives better exposure times. The LS60 (October 2012) has an ERF which is all that is needed in the system and a nice evn filter effect which is good for full discs..
LS60 set up for full disk double stack imaging
PGR Chameleon, motor focus and Solar finder on LS60 and EQ5
Coronado SM40 without ERF double stacking the LS60
I modified the LS75 with pressure tuning by adding a port and sealing the etalon and ERF with O-rings. It was possible to tune it but the pressure was enough to bend the etalon glass and decontact it. It was easy to click it back as only one spacer detached. I did this a few times and then gave up with the experiment. I also managed to drop the ERF and break it.
I have done some animations using K3CCD2 on auto at 1 minute interval sometimes produces some interesting GIF files. IC capture is my normal camera software but it has no interval capture option. I have now got a PGR Chamelon to use USB in a new laptop, after failing to get the firewire adapter to work with my DMK31 and Win 7. I can do animations with Firecapture which has a simple option for this. I use Michael Buxton's method to align the images in Registax 5 and Imageready to make a gif file with a short delay at the end (0.2s usually). In general I am using Avistack2 for stacking except for occasional prominence shots which work better in Registax 6. For single images I now prefer AutoStakkert because it is simple and reliably effective for most shots.
I am following the developments on the SolarChat forum about iterative unsharp mask in Photoshop instead of wavelets in Registax or Avistack with interest and trying things out, I think it it better for most things, perhaps not for CaK full discs.
2014 to 2016
In order to get better Ha full discs I bought an LS60 (March 2014) filter to add to the LS60 pressure tuned scope which was giving me a good even filter effect. Now I can get a single exposure that records disc surface and prominences together, which I particularly like.
LS60 PT scope with LS60, motor focus and Coronado solar finder, UV/IR cut and Chameleon 3 with Rowan astronomy tilt adpater for full discs
I have also started using Firecapture which is very good for time lapse with a reticle and autorun features. New processing software has come along which helps automate things. imPPG and Stackistry help quick processing and aligning, and Autostakkert2 is very good for stacking AVI files in batches. This has all helped to get 30 second cadence animations for minutes at a time with automatic batch processing.
I also decided to get a camera with more pixels and a bigger chip which gets a full disc at prime focus with the LS60 and with a x0.5 reducer for the ED80 for CaK and white light. I chose the PGR Chameleon 3 (March 2016) with IMX265 chip, 2048x1535 pixels (3.45um) and it will run at 36fps or more in ROI mode on a USB3 express card on my laptop.
ED80 and Lunt CaK B600 module, x0.5 focal reducer, IR cut and Chameleon 3 for CaK full discs
ED80, Astrosolar ND3.8 film, x0.5 focal reducer, Baader continuum and IR cut filter for white light full discs
In order to improve things in this windy place I have bought a HEQ5 mount which is very much easier to use that the EQ5. I am hoping to get guided time lapse imaging at moderate magnification. I needed to get a Rowan astronomy tilting unit to reduce the Newton's rings in Ha with the new camera. This seems to be working well.
PST mod Celestron C6 150mm f8, Lunt B1200, Baader 110mm CERF inside the tube, UV/IR cut and Chameleon 3
Internal Baader CERF
The Celestron C6 PST mod has been improved with a more appropriate focal length lens in the PST part to match the f8 scope (rather than f10 of the PST).
New lens for the PST etalon to match the f8 scope better (not exact but nearest I could find)
The couplers have been improved with T coupling tubes so the sweet spot is more reliably central and with the new bigger camera chip it can be optimised by ROI selection, giving moderate magnification and 70 fps. I can also do 2x2 binning and get a shorter exposure time and faster frame rate, which with the use of a x2 Barlow lens gives a better image in Ha.
I still have the ED100 which can be used with the CaK module, Astrosolar film or the Lunt60 etalon for medium close up in three lights.