Merlin66

Robin, The artefacts come from sharpening. I've extracted a few frames from a full solar disk, 9 sec scan, which show the "normal" cropped H alpha spectrum used to re-construct the SHG image. ( Cropped to 1150 x 170 for the GIF) You can see the "wiggles" in the Ha line caused by the surface features and a couple of sunspots tracking across. The wiggles do impact on all lines (?) but I accept the telluric should only show the seeing. The solar image shows the results from this full scan. Ken

The attached screen shot shows a few things: 1. The Baader 7nm Ha filter actually has peak transmission at 6580A. 2. The movements in the solar surface are clearly seen as "wiggles" in all the absorption lines. The measured resolution R=33529 and the dispersion 0.0635 A/pixel match up pretty well with the SimSpec results for the MiniSHG.

You’ve given me some new target wavelength for the MiniSHG.

I also have a set of those Man in flight cards. Brings back memories. We have a few cigarette card collections framed - wild flowers, Scottish Clans and aircraft from the 1930’s

Very neat and tidy! Jim, The angle is approx 3.15 deg for a 100 l/mm grating. The formula: sin B = n*N*L where B is the deviation angle, n, the number of lines (l/mm) N is the order of the spectra (usually one) and L the wavelength. for a 100 l/mm grating, 1st order at 550nm (green) sin B = 1*100*550*10^-6 B = 3.15 deg. Ken

Should be close to 105mm from the rear edge of the reducer body. As shown with your dimension "D" (the 85mm was for the x0.33 reducer - and a one off crap batch of x0.63 reducers)

+1 from me. The lodestar IS the guide camera.

The latest Astroart 8 has an animation feature. I extracted a series of images about 0.2A apart going from about +1A in the red wing to -1A in the blue. Based on a 9sec scan with the MiniSHG. Reduced to 50% for uploading. Enjoy!

Going from White Light solar observing to H alpha is a major step, both in costs and complexity. 1. No. Solar Ha needs a very narrow band (1A or better) this means using an etalon filter. 2. Generally yes. The common etalon filters LS60 etc mount at the front and use a secondary element "blocking filter" at the eyepiece end. https://davidastro.com/lunt-60mm-ha-etalon-filter/ 3. DSLR could be used but for best results a mono camera is the way to go ASI 178, ASI 174 etc. 4. Yes! One option would be the Daystar Quark https://www.daystarfilters.com/Quark.shtml Using the WO 73 with a suitable filter would probably be the way to go.

Yeah, Astroart punches well above its weight. A highly capable and versatile software package. Does everything from preprocessing, guiding, plate solving to final image processing. Now includes an animation feature. I use it for the solar images from the MiniSHG.

Nigella, Welcome back to the spectroscopic fold. Your ASI 178 mm would be much better than your DSLR. You would need to watch the spacing as the chip is only 5 x 7.4mm. We're here if you need us.

Nigel, That's a 600 l/mm replica transmission grating. It's normally used in a "school spectroscope" and it's of limited use in astronomy. You really would need to mount it in a basic slit spectrograph like the Watkin's design.

Check out Sylvain Weiller's page: http://sweiller.free.fr/PST/indexPST.html (about 1/2 down the page)

No, I haven't seen anything other than the S&T article, but it does look very "doable"

What about trying the Kelley-Alder Mirror Flex System?? https://skyandtelescope.org/wp-conte...MirrorFlex.pdf

Section 10.5 CALIBRATION on page 185 of the included manual may help. As long as the images are consistent - size wise, they should be able to be used. Flats...if they are again consistent I don't see an issue. You could always process each nights data and combine the resulting images???

I've been beta testing the V8 for some time...... A fantastic upgrade to an already excellent program. Punches well above its weight Fabio has sent this: Hello, a new major version of Astroart was released today: http://www.msb-astroart.com These are the new features: Image processing New DDP, deconvolution, gradient removal with mask, multiscale denoise and low pass, processing history, improved scripts and macros. Image analysis Seven views (stars, histogram, statistics, history, zoom, 3d, header) with several new features. Color processing New LRGB, trichromy, demosaic, white balance, attenuate channel, saturation, align planes. Preprocessing Image preview, report with graphs, several normalization and rejection methods, faster sigma stacking. Blink and animations Full-screen blink and animations with live annotations. Edit pixel Clone tool, blink, origin of coordinates, improved undo and zoom. Batch photometry User defined reports and graphs. Image browser Optimized for astronomical images, with single and grid layout. Instrumentation ASCOM switches and weather stations, temperature ramps, multicore plate solve. User interface Navigator panel, customizable image border, four themes, new controls. Other Scale marker. Orientation marker with custom color. Find stars with configurable aperture. Configurable fields for star list. Roundness and inclination for stars. Equalize visualization with preview. Deblooming with preview. Remove gradient with preview. Remove gradient with automatic points. Average and Merge with mask. Create mask from stars. Eyedropper tool for masks. Formulas with RGB components. More than 100 new script commands. Normalization via Add, Multiply or Scale. Automatic plate solve for camera images. Automatic plate solve for sequences. Software binning 3x3 for camera images. Telescope centering clicking on the image. Star atlas, CCD frame. Star atlas, bookmarks. Star atlas, mosaic planner. Star atlas, UCAC 5 catalog. Star atlas, faster calibration. Icons for quick flip and rotate. Shortcut for black window background. Options for FITS RowOrder and Creator. Improved Windows DPI scaling. New tutorials and documentation.

Apollo, Each scan takes only 9sec. If your SSD drive is big enough you could record 6 images/ minute or 360 per hour. The SER video file is about 4gb and each image is roughly 2500 x 2500 pixel and 12mb.

Yeah, I agree! Notice the filaproms..... I did a colourised version - just for fun. Enjoy

The usual CaK DIY image - the AR is almost gone and the disk is quiet. The MiniSHG - some interesting results. 1. The "usual" result of a 9sec scan tuned to the centre of Ha wavelength 2. Selecting a wavelength about 0.4A into the Ha wings 3. Selecting the Prom image from the scan (may be a little overexposed??!) All these results from a single 9sec scan. (much shorter than the conventional CaK exposure!!) 4. The results of a 4 image stack (AS3!) I have to say, very impressive! Compare this with #1 above. I think a stack of even more images would give a excellent result. Onwards and Upwards Enjoy..

Ico, I'm using an ED80 stopped to 60mm plus either a Baader Ha 7nm ERF or just an ND0.9 for other wavelengths. https://groups.io/g/astronomicalspectroscopy/topic/85342534?

I had a pair of cable controls fitted with "wheel handles". My mate had a set which hand " long narrow handles" We swapped one of each. This made it much easier in the dark to distinguish between them by feel. Worked for us!

Very nice collection, well presented. I'm testing a MiniSHG based loosely on Christian Buil's SolEx design (but without the 3D printing) The associated INTI software by Valerie Desnoux is exceptionally fast and can present the images (based on 16bit SER files) in seconds!! I didn't include H beta in my quick run of multi-wavelengths but did record all the rest. Using the ASI 178 with 9 sec scans in Declination.

Steve, Well done mate! A couple of points: We still tend to use Angstrom rather than nm for our spectra. Use the "Chart/Crop X axis range" to hide the ends of the profile say 3700A to 7500A Onwards and Upwards

Louise, Glad to see you're posting again. The last year or so living with Covid etc. has slowed many of us down. If it's any consolation, light pollution doesn't exist (well....), we can subtract the background nuisance light to allow the target data to shine through. My friend Valerie Desnoux does her spectroscopy work from the centre of Paris!!!