Lunt 50THa + IMX178-M = how?

I had a similar configuration when I started out in solar (LS50THa + ZWO ASI290MM).  You will have a lot easier time with the feather touch focuser. I upgraded to that to help with ease of focusing and to gain some backfocus.  In the meantime, one trick I recall is having to slide the B600 (or whichever Lunt blocking filter diagonal you have) out to increase the optical path.  Also, I typically shoot with a 2xbarlow and the way that worked for me was to connecting a detachable barlow lens to the nosepiece on the camera.  Hope this helps.  My current setup includes the feathertouch offered through Lunt which works great and the 290MM attached to a Televue 2.5x powermate via their T2 adapter.  See:  https://astrob.in/17kk9k/D/

Also, I found some great advice on the solar chat forum:  https://solarchatforum.com/ 


Good luck and hang in there, it can be done.

I've been able to capture full disk with the LS50Tha/B600/ASI290MM.  I had to attach a 0.5xfocal reducer via an adapter ring (ZWO 1.25" filter thread to M42 thread adapter ring) to the 290MM and thread the 290MM directly to the B600 via M42 threads (both the nosepiece on the 290MM and the corresponding receiving piece on the B600 removed).

Yes the helical focuser is a pain, but it will get you started and you'll really appreciate the feather touch when you get that setup!

I went back and checked some of my imaging calculations for the LS50 and while I needed a 0.5x FR in practice to get full disk with a 290MM, you wont with the 178 sensor.  The sun is about ~0.5 degrees diameter.  With the 290MM at the nominal focal length of 350 mm I can just get 0.5 degrees FOV, but in practice don't quite capture the full disk due to drift/jitter/etc plus I wanted to capture proms extending from the limb so needed more FOV.  With the 178 sensor I calculate a FOV of 0.8 degrees at nominal focal length.  My vague recollection is that I had the hardest time getting focus at nominal focal length with the LS50 (sorry cant remember how I made that work), it worked better with the barlow and standard nosepieces or the 0.5FR attached to the B600 M42 thread.

I have the Lunt 50Tha with the ZWO178mm.  I was able to achieve focus by inserting a ZWO 21mm spacer in the imaging train.

John

Unscrew the adapter on the top of the diagonal.  Screw in the 21mm spacer directly on the diagonal, then screw the Lunt adapter you took off on the other end of the 21mm adapter.  Insert your camera in the Lunt adapter.  With my ASI178mm, I get about half the solar disk.  I have also used an ASI224MC, in which case I do get the entire solar disk.

I have not set this up in awhile, and in looking back at my notes when using the ASI224MC, I removed the Lunt top piece from the diagonal, and  screwed on the 21mm spacer to the diagonal.  I then removed the nose piece from the camera and screwed the camera directly to the 21mm spacer and did not use the Lunt adapter at all.  

I had to experiment a while to get proper focus and it has been so long, I have forgotten which way works best, but in either case I used the ZWO 21 mm spacer that came with a ZWO cooled camera.

Sorry to be so confusing…

Hope that helps.

John

The difference may have been  because I used two different configurations for each camera.

It's been about 5 months since I have solar imaged, so I need to set it up again.

John

John Richards:
There have been several threads on Cloudy Nights about achieving focus with the Lunt 50 and a camera,  you may want to read.  Here is one https://www.cloudynights.com/topic/681443-cant-focus-my-lunt-ls50-using-zwo-asi178/  

It seems different configurations work for different people.

John

Shiet, no wonder I don't get any focus.
If the case is as the link mentions, that everyone's getting different back focus ranges, then there's some severe errors in the making of the telescope itself.

Gonna ask for all kinds of extension tubes, all from 2 mm to 40 mm just to be sure.

@John Richards thanks for the heads up and image. Can't wait to test mine.

I spoke with Lunt and according to them I should be able to just attach my camera directly to the diagonal to be able to use it for solar imaging. I prove them wrong, since I've tried the most of what to do except this method of yours. Awaiting for my adapters to arrive with the courier so I can start do some solar magic myself.

Just spoke with the store and I had to order anti-vibration pads for my mount's tripod, since I'm shooting from my balcony. But until that I'm going to give my SolarQuest a last chance to work since it had some struggle to stay on target. Also requested a lighter counterweight for the mount due to the Lunt's light weight. 5kg (11 lbs) is a bit overkill for such telescope, and super hard to find the perfect balance with.

Did you capture AR 2974's activity anything? It had a huge eruption recently.

@Miska Saarikko ,  Just went to your website, my wife is a nature photographer and loved all your nature and aurora images.

John

Miska,

The way I have processed solar images is similar to how I process planetary images.  I start with a video taken in Sharpcap.  Then run it through PIPP (Planetary Imager Pre Processor) which pre processes the video, then I use either or both Autostakkert or RegiStax to break the video down into individual frames, pick the best and stack them into an image.  Registax also has tools to sharpen, adjust the wavelets, etc. on the final image.  I also have used an old version of LightRoom to adjust the image.  I do use Pixinsight for DSO images, but generally not for Solar images.   If you want to see how someone acquires and processes a solar image, here is a YouTube video from Chuck's Astrophotography   https://www.youtube.com/watch?v=h_SQe2MLOvw     PIPP, RegiStax and AutoStakkert are all free downloads.


I have really liked the Ioptron mounts.  I started with the Smart EQ Pro + which I used for wide field astrophotography for several years, though I recently sold it.  I also have a CEM25P, which I also really liked.  About a month ago I got the GEM45 with the Ipolar and just added the Iguider this week.  I added the Iguider when I realized if I used that, I could remove the 50mm guidescope mounted on top of my DSO refractor and replace it with the Lunt 50.   Installation of the Iguider was easy and it worked right away, in fact, it is running right now.

I passed your message to my wife 

John

@Miska Saarikko  Wow, yes your solar images were great!

To properly align your GEM28 for DSO imaging,  there are basically two steps, polar alignment and then GoTO alignment. For solar imaging, it's a bit simpler.  But first, you must make sure all of the settings are correct in the hand controller settings menu,  time, number of minutes difference from UTC, Lat, Long, etc.  If you are in Stockholm, I believe you are 2 hours ahead of UTC, so you would enter "+120" as your UTC offset.  Also, indicate if you are on daylight savings time (DST) , Y or N.  For GPS location, the easiest way is to get the optional GPS receiver for the GEM28, which will automatically enter the coordinates.  If you don't have that, you can use the GPS coordinates in your cell phone and enter them.

For Solar imaging, you will need to Polar align as close as you can, but it's not quite as critical as DSO imaging.  If nothing else, just set up the GEM28 using a compass and if you can correct for magnetic declamation for Sweden, that would help.  You obviously can't do a 1 or 2 star alignment, since you can't see any stars during the day, so skip that.  Once you have everything set up, use the hand controller to slew to the sun.  It should point pretty close to the Sun's position.  If it's way off or points to the ground, you probably don't have the settings correct in the setup menu.  It is unlikely it will be dead on target to the Sun, but should be at least in the general direction.  Use the arrow buttons on the hand controller to center it, you can also use the "sync to target" routine.  You may find it easier to use an eyepiece rather than the camera to center the Sun in the FOV.  The part were you center the Sun and find focus, may take you some time, don't get frustrated, just keep trying.  Once you have things centered and the camera focused, make sure you are tracking in "solar" not "Sidereal".  Start your video recording, you may find you have to use the arrow buttons on the hand controller occasionally to keep the sun in the FOV.

If you decide to do DSO astrophotography with the GEM 28, polar alignment becomes much more critical for accurate guiding and GOTO accuracy.  There is a "Polar Iterate Align" routine in the GEM28 hand controller that allows you to polar align, even if you can't see the celestial pole.  I have never used it, and don't know how it works.  Another option is just to setup somewhere where Polaris is visible and use the Ipolar or polarscope, which ever you have.  You will also have to follow the 1,2, or 3 star alignment procedures to calibrate your goto's.   Also, if you plan on doing DSO astrophotography, you can skip the star alignment routines and use a laptop, ASIAIR or other device connected to the GEM28  Then, once you Polar Align, you can use "Plate Solving" on a  device like the ZWO ASIAIR, or on laptop software such as SGP, Astrophotography Tool, NINA, etc. and this will put you dead on your target.

Setting up any equatorial mount the first time is always a learning experience and it will probably take several outings before you feel comfortable using it.

Hope this helps,

John