Merlin66

IMHO double stacking the Continuum filter brings limited benefits. There are no defined emission/ absorption features in that region of the spectrum. A polarising filter is always useful to reduce excess light. Note: what ever solar filter system you use must have at least an ND5 reduction (for visual) Some polarising filters still pass some IR wavelengths - best to double check with the supplier.

Old time speak for "Object Glass" = refractor objective lens

I have a spreadsheet I downloaded (from someone - I think on SolarChat) which shows the result of stacking two Gaussian transmission curves. The peak transmission drops and the bandwidth tightens due to the multiplication of the transmission curves. Say if each curve has a peak of 90% transmission, the the combined peak would be (0.9 x 0.9) = 0.81% Likewise if you multiply each point "down the curve" the resultant bandwidth reduces. If each filter is identical, the bandwidth reduction will be around 30%. I'll upload the spreadsheet when I find it. Gausian curve addition.XLS

You've got about three years to save up for the double stack....by then Cycle 25 should have kicked in bringing some sunspots etc. In the meantime enjoy what you have. I have a DS SM60 but at the moment mostly use it SS to view and image the occasional proms. Single stack is much better for the proms, the wider bandwidth suppresses the Doppler shifts. The DS definitely improves surface contrast (when there's something to see )

It’s due to the atmosphere. Differential refraction of the atmosphere, most noticeable when viewing objects at lower altitude, acts like like a prism.

It's pretty well covered in the downloadable Synscan manual. Section 11.4 gives all the details. You can use the "SNAP" port on the mount, or the multi purpose port on the hand controller.

Carole, The online AstroArt Guide (part of the AA7 download) has some basic tutorials to get you started.

+1 from me.

Hmmm Don't know, never ever tried it that way....but you do need some means of re-focusing the optical beam emerging from the grating. Any camera (with lens) will work... (This example isn't mine but shows a Ronchi test set-up with compact camera) https://stellafane.org/tm/atm/test/ronchigrams.html http://www.mmresearch.com/articles/article1/

D, I use my Ronchi grating with various cameras and telescopes. My grating has a 1.25” nosepiece which fits to the focuser instead of an eyepiece. without using a camera, set up the grating and look through it at a star.... you should see an out of focus disk with numerous lines across it, use the telescope focuser, the closer the grating gets to focus, the less lines are seen. Its usual to work at a focus which gives around five or six lines visible. The job of the camera plus lens is to replace the eye. Position the camera/ lens combo behind the grating and focus the camera to give clear image of the lines. Hope that helps.

Unfortunately this is the situation. I've had bad experiences in the past with T thread adaptors. Yeah, all M42 x 0.75 threads.......but don't fit each other. I do agree that Baader's strategy seems to work. Never any issues with their threaded gear.

Added to that, I’d recommend starting with the 600 l/mm grating. You can use BASS Project to do all your spectral processing. Any issues/ concerns just let us know.

Just interested in your comment... I use plate solving and just open the wcs.fit image in CdC to display it.... What editing do you have to do??

Back in the 80's I did a similar overlay (for photographs) for the Tirion Sky Atlas. Still with me.....

Have a look at AstroArt. http://www.msb-astroart.com/ It punches well above it's weight. I use it for all my camera acquisition, pre-processing and final image processing. Recommended.

The attached images show the affect of the FULL mod on the Canon 1000D The first image shows the spectrum recorded with the FULL mod The second the spectrum through the front (#1 filter on the graph) anti-alias/ dust shake mirror. You'll see it's an effective UV/IR filter. The #1 filter assembly as removed and the transmission graphs for both filters.

What exactly were you using to take and process these granulation images??

+1 for AstroArt it does 99% of what you you need to do. Highly recommenced.

The full mod doesn't allow standard camera lenses to come to focus. I needed to add a clip in Astronomik clear filter to use my lenses.

Yeah, A six inch steel rule works well.

Yes, the laser needs to be checked before you start. I'm suggesting that the return spot from the objective replaces the Suiter "side illuminated Cheshire".

Just take your time....use the flat tips to unscrew the retainer.

Bruce, I would have to assume any “issues” (ie aberrations, mis-collimation) in the collimating scope would be transferred to the scope under test. A usual double pass set-up uses a master reflector to pass the light beam twice through the same optics.

Hmmmm, an extra 3 metres on 10 light years won’t make much difference..... try the reflected spot from the sun on a Xmas decoration ball to give a artificial star.....but you still need some distance....

I have used a very thin smear of boot polish on adapter threads to prevent jamming for many years. Works very well, but you need to take care.....