Merlin66

https://www.meade.com/coronado-personal-solar-telescope-pst.html "news of my demise is premature".... The only comment I have - they said it uses a 30mm internal etalon, when the effective diameter is only 20mm!!!

Matt, The download link didn't work for me, but I found the site: https://ft.rognemedia.no/ I'm not sure how effective this process is on solar images which only show "some" NR - not extending across the whole image. Worth experimenting with???? (AstroArt also has a FFT filter, but it didn't work too well for me. I asked Fabio, and he said it (the FFT filter) only works where the fringes extend across the whole image. Bumma!)

Hmmm, an older thread.......... Just a comment about "dimmer views through a double stack" This is NOT due to having an ERF in both etalons - the transmission of an ERF at H alpha is around 90%, so a second ERF would only give an addition loss of 10% of the light. The impact of the double stack is to reduce the bandwidth of the "effective" etalon, from around 0.8A to 0.5A. This significantly reduces the light throughput. A reduction of around 40%. All things being equal, a single etalon with a bandwidth of 0.5A would give similar views to a DS with a 0.5A bandwidth.

When I first tried my SM60 double stack many years ago I was told the same thing - that they had to be matched.....this turned out as Trump would say to be "fake news". The real issue is where the design CWL (central wavelength) of each etalon is located. All tilt tuned etalons are designed to sit just above (towards the red wing) the H alpha wavelength, and require some degree of tilt to move the CWL to exactly the H alpha wavelength. In effect this means independently tilting each of the front etalons to bring them both to the same wavelength (where maximum brightness and contrast is achieved). Certainly tuning a DS is a little more complicated, but with patience a great result can be achieved. I've no comment on the air pressure v's tilt (or the "Richview" pressure ) tuning.

John, I thought the more recent Baader filters had solved this halo issue????

Jim, OK. Focusing the spectrograph on the telescope is a three stage process. 1. Set the guider to focus on the slit gap. This can be done in subdued lighting and should ensure the telescope is focused on the front of the slit gap (see #2) 2. Adjust the telescope focuser to bring the target star (or any star really) onto the slit in tight focus, as viewed from the guider. This should give you the thinnest spectral line only a few pixels in height. 3. Focus the imaging camera on a reference line close to your target wavelength. Aim for a minimum FWHM, around 3 pixel would be good. This means the imaging camera is well focused on the rear of the slit plate gap. Depending where you're targetting within the spectrum, you'll find you need to re-focus the imaging camera to account for chromatic/ field curvature. I always take a reference image immediately prior to taking a target image and measure the reference line (Bass Project/ Measurements) to determine the resolution R value. You'll need this reference image for wavelength calibration. The telescope (hopefully) should maintain focus onto the slit gap, so moving to different targets just means checking the imaging camera focus. Standardise on a sub exposure length, to suit your mount's capabilities (and your guider accuracy -PHD etc.) I generally use 240 sec subs. The total exposure will depend on the target magnitude, look at the sub's profile (I use AstroArt) to check the max ADU - shouldn't be saturated....go for as many subs as you can to improve SNR. I usually aim for 10 subs - total exposure 2400 sec ( 40 min) Any questions just ask.......

Yeah, I was lucky, the original SM60 had the external etalon...... I sold it and bought an other SM60 external etalon, then an other......to fit the ED80. It's worked very well for me. First image is today's arrangement....the second from 2010

No, you should be able to use the handcontroller to control your mount. for PHD just add the HEQ5 as the Aux mount.

Russ, Thanks for the kind comment. Now if I could persuade my wife to move from the coast to inland Australia I'm sure the seeing would be MUCH better......

PaintShopPro at a reasonable once of price handles layers and many of the PS plugins.....

I use a Starlight Lodestar for guiding my NEQ6pro mount and ST-4 connections and EQMod. The Aux in PHD needs to be set to "EQmod ASCOM HEQ5/6" - this then allows PHD to access the RA and Dec of the target object. Hope this helps.

It’s the same or worse in Australia..... I’ve been using a SM60 double stack on my ED80 for the past ten years....it would be great to upgrade but my pension budget doesn’t allow that.

To help identify variable stars and similar changing objects I use a solved image (astrometry.net). This provides a accurate reference frame for the image which can then be "blinked" against a detailed star map - I use the features of Cartes du Ciel. Any "new" star - asteroid or comet will show during the blink as having no matching star image on the underlying star chart. You can set the search limit magnitude to make things easier... Hope that helps.

Matt, When you say you used PS......was that the Photomerge option? (file/automate/photomerge) I found ICE and other programs didn't work too well for me, but that Photomerge did a pretty good job.

Yes, AstroArt punches well above it's weight. An under-rated piece of excellent software. Fabio, the developer, has given users unlimited support over the years.

Sean, Yes, that's the replacement filter you need.

Sean, The ITF in the bottom of the eyepiece holder is definitely gone to meet it's maker.....effectively dead! You can get a drop-in replacement from Maier Photonics in the US about $110. Could be the source of your problems......

The UCAC4 catalogue in CdC will get you down to 16mag, below that you need the GAIA catalogue which goes down I think to 20 mag!

Hmmmm Just in time for Cycle 25....

Sean, Still thinking about your problem...... It may be worthwhile unscrewing the eyepiece holder from the "black box" and checking the condition of the ITF filter (located at the bottom of the eyepiece holder tube) Any sign of "rattling" when you shake the PST (gently!) I've seen the collimation lens on the etalon assembly come loose......

John, Thanks for that.. Seems to confirm the CN solution "tweak the end of the tube to suit" Onwards and Upwards

Has anyone got info on how the SW ED80 objective is collimated? I've just removed the front cell, unscrews from the tube, and there are no obvious signs of adjustment screws.... Dr Google doesn't have much to say about collimating the SW ED80... The nearest I could find was the CN discussion: https://www.cloudynights.com/topic/4...on-of-my-80ed/ Is this as good as it gets???? Ken

Johan, That's a pretty good result from a PST. Shows the AR and the proms...... Well done! Ken

I use the Baader Hyperion x2.25 Barlow for solar imaging. It works very well, I’m impressed. The T thread connection is very helpful.